[v3,1/2] iio: adc: mt6360: Add ADC driver for MT6360

Commit Message

Gene Chen Aug. 24, 2020, 9:06 a.m. UTC

From: Gene Chen <[e-mail]>

Add MT6360 ADC driver include Charger Current, Voltage, and
Temperature.

Signed-off-by: Gene Chen <[e-mail]>
---
 drivers/iio/adc/Kconfig      |  11 ++
 drivers/iio/adc/Makefile     |   1 +
 drivers/iio/adc/mt6360-adc.c | 366 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 378 insertions(+)
 create mode 100644 drivers/iio/adc/mt6360-adc.c

Comments

kernel test robot Aug. 27, 2020, 12:16 p.m. UTC | #1

Hi Gene,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on iio/togreg]
[also build test WARNING on v5.9-rc2 next-20200827]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Gene-Chen/iio-adc-mt6360-Add-ADC-driver-for-MT6360/20200824-170948
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
config: i386-randconfig-s031-20200827 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.2-191-g10164920-dirty
        # save the attached .config to linux build tree
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[e-mail]>


sparse warnings: (new ones prefixed by >>)

>> drivers/iio/adc/mt6360-adc.c:125:20: sparse: sparse: incorrect type in assignment (different base types) @@     expected unsigned short [assigned] [usertype] adc_enable @@     got restricted __be16 [usertype] @@
>> drivers/iio/adc/mt6360-adc.c:125:20: sparse:     expected unsigned short [assigned] [usertype] adc_enable
>> drivers/iio/adc/mt6360-adc.c:125:20: sparse:     got restricted __be16 [usertype]
>> drivers/iio/adc/mt6360-adc.c:179:20: sparse: sparse: incorrect type in assignment (different base types) @@     expected unsigned short [addressable] [assigned] [usertype] adc_enable @@     got restricted __be16 [usertype] @@
>> drivers/iio/adc/mt6360-adc.c:179:20: sparse:     expected unsigned short [addressable] [assigned] [usertype] adc_enable
   drivers/iio/adc/mt6360-adc.c:179:20: sparse:     got restricted __be16 [usertype]

# https://github.com/0day-ci/linux/commit/0e757f71bbdf50d4dad3b79e5f30c7f2386ae082
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Gene-Chen/iio-adc-mt6360-Add-ADC-driver-for-MT6360/20200824-170948
git checkout 0e757f71bbdf50d4dad3b79e5f30c7f2386ae082
vim +125 drivers/iio/adc/mt6360-adc.c

   106	
   107	static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
   108	{
   109		u16 adc_enable;
   110		u8 rpt[3];
   111		ktime_t start_t, predict_end_t;
   112		long timeout;
   113		int value, ret;
   114	
   115		mutex_lock(&mad->adc_lock);
   116	
   117		/* select preferred channel that we want */
   118		ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
   119					 channel << MT6360_PREFERCH_SHFT);
   120		if (ret)
   121			goto out_adc;
   122	
   123		/* enable adc channel we want and adc_en */
   124		adc_enable = MT6360_ADCEN_MASK | BIT(channel);
 > 125		adc_enable = cpu_to_be16(adc_enable);
   126		ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
   127		if (ret)
   128			goto out_adc;
   129	
   130		start_t = ktime_get();
   131		predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
   132	
   133		if (ktime_after(start_t, predict_end_t))
   134			predict_end_t = ktime_add_ms(start_t, 25);
   135		else
   136			predict_end_t = ktime_add_ms(start_t, 75);
   137	
   138		enable_irq(mad->irq);
   139	adc_retry:
   140		reinit_completion(&mad->adc_complete);
   141	
   142		/* wait for conversion to complete */
   143		timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
   144		if (timeout == 0) {
   145			ret = -ETIMEDOUT;
   146			goto out_adc_conv;
   147		} else if (timeout < 0) {
   148			ret = -EINTR;
   149			goto out_adc_conv;
   150		}
   151	
   152		ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
   153		if (ret)
   154			goto out_adc_conv;
   155	
   156		/* check the current reported channel */
   157		if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
   158			dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);
   159			goto adc_retry;
   160		}
   161	
   162		if (!ktime_after(ktime_get(), predict_end_t)) {
   163			dev_dbg(mad->dev, "time is not after one adc_conv_t\n");
   164			goto adc_retry;
   165		}
   166	
   167		value = (rpt[1] << 8) | rpt[2];
   168	
   169		ret = mt6360_adc_convert_processed_val(mad, channel, &value);
   170		if (ret)
   171			goto out_adc_conv;
   172	
   173		*val = value;
   174		ret = IIO_VAL_INT;
   175	
   176	out_adc_conv:
   177		disable_irq(mad->irq);
   178		adc_enable = MT6360_ADCEN_MASK;
 > 179		adc_enable = cpu_to_be16(adc_enable);
   180		regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
   181		mad->last_off_timestamps[channel] = ktime_get();
   182		/* set prefer channel to 0xf */
   183		regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
   184				   0xF << MT6360_PREFERCH_SHFT);
   185	out_adc:
   186		mutex_unlock(&mad->adc_lock);
   187	
   188		return ret;
   189	}
   190	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[e-mail]

Jonathan Cameron Aug. 29, 2020, 5:11 p.m. UTC | #2

On Mon, 24 Aug 2020 17:06:24 +0800
Gene Chen <[e-mail]> wrote:

> From: Gene Chen <[e-mail]>
> 
> Add MT6360 ADC driver include Charger Current, Voltage, and
> Temperature.
> 
> Signed-off-by: Gene Chen <[e-mail]>
Hi Gene,

A few comments inline.  The big one centres on why we can't
expose the channels as _raw, _offset and _scale?

Thanks,

Jonathan

> ---
>  drivers/iio/adc/Kconfig      |  11 ++
>  drivers/iio/adc/Makefile     |   1 +
>  drivers/iio/adc/mt6360-adc.c | 366 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 378 insertions(+)
>  create mode 100644 drivers/iio/adc/mt6360-adc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 66d9cc0..07dcea7 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -703,6 +703,17 @@ config MCP3911
>  	  This driver can also be built as a module. If so, the module will be
>  	  called mcp3911.
>  
> +config MEDIATEK_MT6360_ADC
> +	tristate "Mediatek MT6360 ADC Part"
> +	depends on MFD_MT6360
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
> +	help
> +	  Say Y here to enable MT6360 ADC Part.
> +	  Integrated for System Monitoring include
> +	  Charger and Battery Current, Voltage and
> +	  Temperature
> +
>  config MEDIATEK_MT6577_AUXADC
>  	tristate "MediaTek AUXADC driver"
>  	depends on ARCH_MEDIATEK || COMPILE_TEST
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 90f94ad..5fca90a 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -65,6 +65,7 @@ obj-$(CONFIG_MAX9611) += max9611.o
>  obj-$(CONFIG_MCP320X) += mcp320x.o
>  obj-$(CONFIG_MCP3422) += mcp3422.o
>  obj-$(CONFIG_MCP3911) += mcp3911.o
> +obj-$(CONFIG_MEDIATEK_MT6360_ADC) += mt6360-adc.o
>  obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o
>  obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
>  obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
> diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c
> new file mode 100644
> index 0000000..5eed812
> --- /dev/null
> +++ b/drivers/iio/adc/mt6360-adc.c
> @@ -0,0 +1,366 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020 MediaTek Inc.
> + *
> + * Author: Gene Chen <[e-mail]>
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/interrupt.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/irq.h>
> +#include <linux/kernel.h>
> +#include <linux/ktime.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define MT6360_REG_PMUCHGCTRL3	0x313
> +#define MT6360_REG_PMUADCCFG	0x356
> +#define MT6360_REG_PMUADCRPT1	0x35A
> +
> +/* PMUCHGCTRL3 0x313 */
> +#define MT6360_AICR_MASK	0xFC
> +#define MT6360_AICR_SHFT	2
> +#define MT6360_AICR_400MA	0x6
> +/* PMUADCCFG 0x356 */
> +#define MT6360_ADCEN_MASK	0x8000
> +/* PMUADCRPT1 0x35A */
> +#define MT6360_PREFERCH_MASK	0xF0
> +#define MT6360_PREFERCH_SHFT	4
> +#define MT6360_RPTCH_MASK	0x0F
> +
> +enum {
> +	MT6360_CHAN_USBID = 0,
> +	MT6360_CHAN_VBUSDIV5,
> +	MT6360_CHAN_VBUSDIV2,
> +	MT6360_CHAN_VSYS,
> +	MT6360_CHAN_VBAT,
> +	MT6360_CHAN_IBUS,
> +	MT6360_CHAN_IBAT,
> +	MT6360_CHAN_CHG_VDDP,
> +	MT6360_CHAN_TEMP_JC,
> +	MT6360_CHAN_VREF_TS,
> +	MT6360_CHAN_TS,
> +	MT6360_CHAN_MAX,
> +};
> +
> +struct mt6360_adc_data {
> +	struct device *dev;
> +	struct regmap *regmap;
> +	struct completion adc_complete;
> +	struct mutex adc_lock;
> +	ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> +	int irq;
> +};
> +
> +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> +{
> +	return ((val * multiplier) + offset) / divisor;

Why could we not report these values to userspace or consumer drivers and let
them deal with the conversion if they actually needed it?
Mapping this to

(val + new_offset) * multiplier would be a little messy, but not too bad.

The advantage would be that we would then be providing the data needed
to get real units for values read from the buffers without having to
do all the maths in kernel (without access to floating point).

 
> +}
> +
> +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> +{
> +	unsigned int regval = 0;
> +	const struct converter {
> +		int multiplier;
> +		int offset;
> +		int divisor;
> +	} adc_converter[MT6360_CHAN_MAX] = {
> +		{ 1250, 0, 1}, /* USBID */
> +		{ 6250, 0, 1}, /* VBUSDIV5 */
> +		{ 2500, 0, 1}, /* VBUSDIV2 */
> +		{ 1250, 0, 1}, /* VSYS */
> +		{ 1250, 0, 1}, /* VBAT */
> +		{ 2500, 0, 1}, /* IBUS */
> +		{ 2500, 0, 1}, /* IBAT */
> +		{ 1250, 0, 1}, /* CHG_VDDP */
> +		{ 105, -8000, 100}, /* TEMP_JC */
> +		{ 1250, 0, 1}, /* VREF_TS */
> +		{ 1250, 0, 1}, /* TS */
> +	}, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> +	int ret;
> +
> +	sel_converter = adc_converter + chan_idx;
> +	if (chan_idx == MT6360_CHAN_IBUS) {
> +		/* ibus chan will be affected by aicr config */
> +		/* if aicr < 400, apply the special ibus converter */
> +		ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> +		if (ret)
> +			return ret;
> +
> +		regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> +		if (regval < MT6360_AICR_400MA)
> +			sel_converter = &sp_ibus_adc_converter;
> +	}
> +
> +	*val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> +					sel_converter->divisor);
> +
> +	return 0;
> +}
> +
> +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> +{
> +	u16 adc_enable;
> +	u8 rpt[3];
> +	ktime_t start_t, predict_end_t;
> +	long timeout;
> +	int value, ret;
> +
> +	mutex_lock(&mad->adc_lock);
> +
> +	/* select preferred channel that we want */
> +	ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> +				 channel << MT6360_PREFERCH_SHFT);
> +	if (ret)
> +		goto out_adc;
> +
> +	/* enable adc channel we want and adc_en */
> +	adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> +	adc_enable = cpu_to_be16(adc_enable);

Use a local be16 to store that. It will make it a little clearer
that we are doing something 'unusual' here.  Perhaps a comment on
why this odd code exists would also help?

> +	ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> +	if (ret)
> +		goto out_adc;
> +
> +	start_t = ktime_get();
> +	predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> +
> +	if (ktime_after(start_t, predict_end_t))
> +		predict_end_t = ktime_add_ms(start_t, 25);
> +	else
> +		predict_end_t = ktime_add_ms(start_t, 75);
> +
> +	enable_irq(mad->irq);
> +adc_retry:
> +	reinit_completion(&mad->adc_complete);
> +
> +	/* wait for conversion to complete */
> +	timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> +	if (timeout == 0) {
> +		ret = -ETIMEDOUT;
> +		goto out_adc_conv;
> +	} else if (timeout < 0) {
> +		ret = -EINTR;
> +		goto out_adc_conv;
> +	}
> +
> +	ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> +	if (ret)
> +		goto out_adc_conv;
> +
> +	/* check the current reported channel */
> +	if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> +		dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);

This and the one below feel like error messages rather than debug ones.

> +		goto adc_retry;
> +	}
> +
> +	if (!ktime_after(ktime_get(), predict_end_t)) {
> +		dev_dbg(mad->dev, "time is not after one adc_conv_t\n");

Does this actually happen? If feels like we are being a bit over protective
here.  I'd definitely like to see a comment saying why this protection
might be needed.

> +		goto adc_retry;
> +	}
> +
> +	value = (rpt[1] << 8) | rpt[2];
> +
> +	ret = mt6360_adc_convert_processed_val(mad, channel, &value);
> +	if (ret)
> +		goto out_adc_conv;
> +
> +	*val = value;
> +	ret = IIO_VAL_INT;
> +
> +out_adc_conv:
> +	disable_irq(mad->irq);
> +	adc_enable = MT6360_ADCEN_MASK;
> +	adc_enable = cpu_to_be16(adc_enable);
> +	regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> +	mad->last_off_timestamps[channel] = ktime_get();
> +	/* set prefer channel to 0xf */
> +	regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> +			   0xF << MT6360_PREFERCH_SHFT);
> +out_adc:
> +	mutex_unlock(&mad->adc_lock);
> +
> +	return ret;
> +}
> +
> +static int mt6360_adc_read_raw(struct iio_dev *iio_dev, const struct iio_chan_spec *chan,
> +			       int *val, int *val2, long mask)
> +{
> +	struct mt6360_adc_data *mad = iio_priv(iio_dev);
> +
> +	if (mask == IIO_CHAN_INFO_PROCESSED)
> +		return mt6360_adc_read_processed(mad, chan->channel, val);
> +
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info mt6360_adc_iio_info = {
> +	.read_raw = mt6360_adc_read_raw,
> +};
> +
> +#define MT6360_ADC_CHAN(_idx, _type) {				\
> +	.type = _type,						\
> +	.channel = MT6360_CHAN_##_idx,				\
> +	.scan_index = MT6360_CHAN_##_idx,			\
> +	.extend_name = #_idx,					\
> +	.datasheet_name = #_idx,				\
> +	.scan_type =  {						\
> +		.sign = 's',					\
> +		.realbits = 32,					\
> +		.storagebits = 32,				\
> +		.endianness = IIO_CPU,				\
> +	},							\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),	\
> +	.indexed = 1,						\
> +}
> +
> +static const struct iio_chan_spec mt6360_adc_channels[] = {
> +	MT6360_ADC_CHAN(USBID, IIO_VOLTAGE),
> +	MT6360_ADC_CHAN(VBUSDIV5, IIO_VOLTAGE),
> +	MT6360_ADC_CHAN(VBUSDIV2, IIO_VOLTAGE),
> +	MT6360_ADC_CHAN(VSYS, IIO_VOLTAGE),
> +	MT6360_ADC_CHAN(VBAT, IIO_VOLTAGE),
> +	MT6360_ADC_CHAN(IBUS, IIO_CURRENT),
> +	MT6360_ADC_CHAN(IBAT, IIO_CURRENT),
> +	MT6360_ADC_CHAN(CHG_VDDP, IIO_VOLTAGE),
> +	MT6360_ADC_CHAN(TEMP_JC, IIO_TEMP),
> +	MT6360_ADC_CHAN(VREF_TS, IIO_VOLTAGE),
> +	MT6360_ADC_CHAN(TS, IIO_VOLTAGE),
> +	IIO_CHAN_SOFT_TIMESTAMP(MT6360_CHAN_MAX),
> +};
> +
> +static irqreturn_t mt6360_pmu_adc_donei_handler(int irq, void *data)
> +{
> +	struct mt6360_adc_data *mad = iio_priv(data);
> +
> +	complete(&mad->adc_complete);
> +	return IRQ_HANDLED;
> +}
> +
...

> +
> +static int mt6360_adc_probe(struct platform_device *pdev)
> +{
> +	struct mt6360_adc_data *mad;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*mad));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	mad = iio_priv(indio_dev);
> +	mad->dev = &pdev->dev;
> +	init_completion(&mad->adc_complete);
> +	mutex_init(&mad->adc_lock);
> +
> +	mad->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +	if (!mad->regmap) {
> +		dev_err(&pdev->dev, "Failed to get parent regmap\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = mt6360_adc_reset(mad);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to reset adc\n");
> +		return ret;
> +	}
> +
> +	mad->irq = platform_get_irq_byname(pdev, "adc_donei");
> +	if (mad->irq < 0) {
> +		dev_err(&pdev->dev, "Failed to get adc_done irq\n");
> +		return mad->irq;
> +	}
> +
> +	irq_set_status_flags(mad->irq, IRQ_NOAUTOEN);

As we are going to have a v5 anyway to clean up that endian warning,
please could you add a comment to explain the need for IRQ_NOAUTOEN?

> +	ret = devm_request_threaded_irq(&pdev->dev, mad->irq, NULL, mt6360_pmu_adc_donei_handler, 0,
> +					"adc_donei", indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to register adc_done irq\n");
> +		return ret;
> +	}
> +
> +	indio_dev->name = dev_name(&pdev->dev);
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->info = &mt6360_adc_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = mt6360_adc_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(mt6360_adc_channels);
> +
> +	ret = devm_iio_triggered_buffer_setup(&pdev->dev, indio_dev, NULL,
> +					      mt6360_adc_trigger_handler, NULL);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to allocate iio trigger buffer\n");
> +		return ret;
> +	}
> +
> +	ret = devm_iio_device_register(&pdev->dev, indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to register iio device\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
...

Andy Shevchenko Aug. 30, 2020, 5:39 p.m. UTC | #3

On Mon, Aug 24, 2020 at 12:07 PM Gene Chen <[e-mail]> wrote:
>
> Add MT6360 ADC driver include Charger Current, Voltage, and

include -> that includes

> Temperature.

...

> +       help
> +         Say Y here to enable MT6360 ADC Part.
> +         Integrated for System Monitoring include
> +         Charger and Battery Current, Voltage and
> +         Temperature

We have a wider field for this text. Also, use proper punctuation.

...

> +#include <linux/completion.h>
> +#include <linux/interrupt.h>

> +#include <linux/iio/buffer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>

I would rather move this block after linux/* headers because it's
subsystem related (not so generic).

> +#include <linux/irq.h>

Are you sure about this?

> +#include <linux/kernel.h>
> +#include <linux/ktime.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>

...

> +#define MT6360_AICR_MASK       0xFC

GENMASK() (and include bits.h for that).

> +#define MT6360_ADCEN_MASK      0x8000

> +#define MT6360_PREFERCH_MASK   0xF0

> +#define MT6360_RPTCH_MASK      0x0F

Ditto for all above.

...

> +enum {
> +       MT6360_CHAN_USBID = 0,
> +       MT6360_CHAN_VBUSDIV5,
> +       MT6360_CHAN_VBUSDIV2,
> +       MT6360_CHAN_VSYS,
> +       MT6360_CHAN_VBAT,
> +       MT6360_CHAN_IBUS,
> +       MT6360_CHAN_IBAT,
> +       MT6360_CHAN_CHG_VDDP,
> +       MT6360_CHAN_TEMP_JC,
> +       MT6360_CHAN_VREF_TS,
> +       MT6360_CHAN_TS,

> +       MT6360_CHAN_MAX,

No comma for terminator.

> +};

...

> +       const struct converter {
> +               int multiplier;
> +               int offset;
> +               int divisor;
> +       } adc_converter[MT6360_CHAN_MAX] = {
> +               { 1250, 0, 1}, /* USBID */
> +               { 6250, 0, 1}, /* VBUSDIV5 */
> +               { 2500, 0, 1}, /* VBUSDIV2 */
> +               { 1250, 0, 1}, /* VSYS */
> +               { 1250, 0, 1}, /* VBAT */
> +               { 2500, 0, 1}, /* IBUS */
> +               { 2500, 0, 1}, /* IBAT */
> +               { 1250, 0, 1}, /* CHG_VDDP */
> +               { 105, -8000, 100}, /* TEMP_JC */
> +               { 1250, 0, 1}, /* VREF_TS */
> +               { 1250, 0, 1}, /* TS */
> +       }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;

This is quite hidden in the code. Better to move out from the function at least.

...

> +       start_t = ktime_get();
> +       predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> +
> +       if (ktime_after(start_t, predict_end_t))
> +               predict_end_t = ktime_add_ms(start_t, 25);
> +       else
> +               predict_end_t = ktime_add_ms(start_t, 75);
> +

> +       timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));

Above code full of magic numbers.

...

> +       value = (rpt[1] << 8) | rpt[2];

put_unaligned_be16() (or what is this?)

...

> +       /* set prefer channel to 0xf */

What 0x0f is?

> +       regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> +                          0xF << MT6360_PREFERCH_SHFT);

0xf should be GENMASK() and have its descriptive name.

> +out_adc:

The rule of thumb is to explain in the label what is going to do,
rather than some abstract words. Here, i.e.,
out_mutex_unlock:

> +       mutex_unlock(&mad->adc_lock);

...

> +       if (mask == IIO_CHAN_INFO_PROCESSED)
> +               return mt6360_adc_read_processed(mad, chan->channel, val);
> +
> +       return -EINVAL;

Usual pattern is
 if (err_condition)
  ...handle error...

...

> +       /* 11 ch s32 numbers + 1 s64 timestamp */
> +       s32 data[MT6360_CHAN_MAX + 2] __aligned(8);

We have a better approach now (with a struct being used).

...

> +       u8 configs[3] = {0x80, 0, 0};

Magic.

...

> +static int mt6360_adc_probe(struct platform_device *pdev)
> +{

> +       mad->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +       if (!mad->regmap) {
> +               dev_err(&pdev->dev, "Failed to get parent regmap\n");
> +               return -ENODEV;
> +       }

You may do this before allocation happens. Also consider to introduce
temporary variable to simplify below code, i.e.

struct device *dev = &pdev->dev;
struct regmap *regmap;

...

> +       mad->irq = platform_get_irq_byname(pdev, "adc_donei");
> +       if (mad->irq < 0) {

> +               dev_err(&pdev->dev, "Failed to get adc_done irq\n");

This duplicates the core message.

> +               return mad->irq;
> +       }

...

> +       irq_set_status_flags(mad->irq, IRQ_NOAUTOEN);

Why?


> +       ret = devm_iio_device_register(&pdev->dev, indio_dev);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to register iio device\n");

> +               return ret;
> +       }
> +
> +       return 0;

return ret; (At least, but I would go even further and do return
devm_iio_device_register(); directly)

> +}

...

> +static const struct of_device_id __maybe_unused mt6360_adc_of_id[] = {
> +       { .compatible = "mediatek,mt6360-adc", },
> +       {},

No comma for terminator line.

> +};

Gene Chen Sept. 8, 2020, 6:17 a.m. UTC | #4

Jonathan Cameron <[e-mail]> 於 2020年8月30日 週日 上午1:12寫道：
>
> On Mon, 24 Aug 2020 17:06:24 +0800
> Gene Chen <[e-mail]> wrote:
>
> > From: Gene Chen <[e-mail]>
> >
> > Add MT6360 ADC driver include Charger Current, Voltage, and
> > Temperature.
> >
> > Signed-off-by: Gene Chen <[e-mail]>
> Hi Gene,
>
> A few comments inline.  The big one centres on why we can't
> expose the channels as _raw, _offset and _scale?
>

I think i have 3 reason for use real value,
ADC is used to get real value rather than raw data which is not meaningful.
And I can decide which formula needs apply according to different condition.
Also the junction temperature channel _scale is floating point 1.05
which is not easy to express.

> Thanks,
>
> Jonathan
>
> > ---
> >  drivers/iio/adc/Kconfig      |  11 ++
> >  drivers/iio/adc/Makefile     |   1 +
> >  drivers/iio/adc/mt6360-adc.c | 366 +++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 378 insertions(+)
> >  create mode 100644 drivers/iio/adc/mt6360-adc.c
> >
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 66d9cc0..07dcea7 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -703,6 +703,17 @@ config MCP3911
> >         This driver can also be built as a module. If so, the module will be
> >         called mcp3911.
> >
> > +config MEDIATEK_MT6360_ADC
> > +     tristate "Mediatek MT6360 ADC Part"
> > +     depends on MFD_MT6360
> > +     select IIO_BUFFER
> > +     select IIO_TRIGGERED_BUFFER
> > +     help
> > +       Say Y here to enable MT6360 ADC Part.
> > +       Integrated for System Monitoring include
> > +       Charger and Battery Current, Voltage and
> > +       Temperature
> > +
> >  config MEDIATEK_MT6577_AUXADC
> >       tristate "MediaTek AUXADC driver"
> >       depends on ARCH_MEDIATEK || COMPILE_TEST
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index 90f94ad..5fca90a 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -65,6 +65,7 @@ obj-$(CONFIG_MAX9611) += max9611.o
> >  obj-$(CONFIG_MCP320X) += mcp320x.o
> >  obj-$(CONFIG_MCP3422) += mcp3422.o
> >  obj-$(CONFIG_MCP3911) += mcp3911.o
> > +obj-$(CONFIG_MEDIATEK_MT6360_ADC) += mt6360-adc.o
> >  obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o
> >  obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
> >  obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
> > diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c
> > new file mode 100644
> > index 0000000..5eed812
> > --- /dev/null
> > +++ b/drivers/iio/adc/mt6360-adc.c
> > @@ -0,0 +1,366 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2020 MediaTek Inc.
> > + *
> > + * Author: Gene Chen <[e-mail]>
> > + */
> > +
> > +#include <linux/completion.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/iio/buffer.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/trigger_consumer.h>
> > +#include <linux/iio/triggered_buffer.h>
> > +#include <linux/irq.h>
> > +#include <linux/kernel.h>
> > +#include <linux/ktime.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#define MT6360_REG_PMUCHGCTRL3       0x313
> > +#define MT6360_REG_PMUADCCFG 0x356
> > +#define MT6360_REG_PMUADCRPT1        0x35A
> > +
> > +/* PMUCHGCTRL3 0x313 */
> > +#define MT6360_AICR_MASK     0xFC
> > +#define MT6360_AICR_SHFT     2
> > +#define MT6360_AICR_400MA    0x6
> > +/* PMUADCCFG 0x356 */
> > +#define MT6360_ADCEN_MASK    0x8000
> > +/* PMUADCRPT1 0x35A */
> > +#define MT6360_PREFERCH_MASK 0xF0
> > +#define MT6360_PREFERCH_SHFT 4
> > +#define MT6360_RPTCH_MASK    0x0F
> > +
> > +enum {
> > +     MT6360_CHAN_USBID = 0,
> > +     MT6360_CHAN_VBUSDIV5,
> > +     MT6360_CHAN_VBUSDIV2,
> > +     MT6360_CHAN_VSYS,
> > +     MT6360_CHAN_VBAT,
> > +     MT6360_CHAN_IBUS,
> > +     MT6360_CHAN_IBAT,
> > +     MT6360_CHAN_CHG_VDDP,
> > +     MT6360_CHAN_TEMP_JC,
> > +     MT6360_CHAN_VREF_TS,
> > +     MT6360_CHAN_TS,
> > +     MT6360_CHAN_MAX,
> > +};
> > +
> > +struct mt6360_adc_data {
> > +     struct device *dev;
> > +     struct regmap *regmap;
> > +     struct completion adc_complete;
> > +     struct mutex adc_lock;
> > +     ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > +     int irq;
> > +};
> > +
> > +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> > +{
> > +     return ((val * multiplier) + offset) / divisor;
>
> Why could we not report these values to userspace or consumer drivers and let
> them deal with the conversion if they actually needed it?
> Mapping this to
>
> (val + new_offset) * multiplier would be a little messy, but not too bad.
>
> The advantage would be that we would then be providing the data needed
> to get real units for values read from the buffers without having to
> do all the maths in kernel (without access to floating point).
>
>

As above, if I use formula "(val + new_offset) * multiplier",
the junction temperature channel multiplier will be floating point
1.05, i don't know how to express.

> > +}
> > +
> > +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> > +{
> > +     unsigned int regval = 0;
> > +     const struct converter {
> > +             int multiplier;
> > +             int offset;
> > +             int divisor;
> > +     } adc_converter[MT6360_CHAN_MAX] = {
> > +             { 1250, 0, 1}, /* USBID */
> > +             { 6250, 0, 1}, /* VBUSDIV5 */
> > +             { 2500, 0, 1}, /* VBUSDIV2 */
> > +             { 1250, 0, 1}, /* VSYS */
> > +             { 1250, 0, 1}, /* VBAT */
> > +             { 2500, 0, 1}, /* IBUS */
> > +             { 2500, 0, 1}, /* IBAT */
> > +             { 1250, 0, 1}, /* CHG_VDDP */
> > +             { 105, -8000, 100}, /* TEMP_JC */
> > +             { 1250, 0, 1}, /* VREF_TS */
> > +             { 1250, 0, 1}, /* TS */
> > +     }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> > +     int ret;
> > +
> > +     sel_converter = adc_converter + chan_idx;
> > +     if (chan_idx == MT6360_CHAN_IBUS) {
> > +             /* ibus chan will be affected by aicr config */
> > +             /* if aicr < 400, apply the special ibus converter */
> > +             ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > +             if (ret)
> > +                     return ret;
> > +
> > +             regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > +             if (regval < MT6360_AICR_400MA)
> > +                     sel_converter = &sp_ibus_adc_converter;
> > +     }
> > +
> > +     *val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> > +                                     sel_converter->divisor);
> > +
> > +     return 0;
> > +}
> > +
> > +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> > +{
> > +     u16 adc_enable;
> > +     u8 rpt[3];
> > +     ktime_t start_t, predict_end_t;
> > +     long timeout;
> > +     int value, ret;
> > +
> > +     mutex_lock(&mad->adc_lock);
> > +
> > +     /* select preferred channel that we want */
> > +     ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > +                              channel << MT6360_PREFERCH_SHFT);
> > +     if (ret)
> > +             goto out_adc;
> > +
> > +     /* enable adc channel we want and adc_en */
> > +     adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> > +     adc_enable = cpu_to_be16(adc_enable);
>
> Use a local be16 to store that. It will make it a little clearer
> that we are doing something 'unusual' here.  Perhaps a comment on
> why this odd code exists would also help?
>

ACK

> > +     ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > +     if (ret)
> > +             goto out_adc;
> > +
> > +     start_t = ktime_get();
> > +     predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> > +
> > +     if (ktime_after(start_t, predict_end_t))
> > +             predict_end_t = ktime_add_ms(start_t, 25);
> > +     else
> > +             predict_end_t = ktime_add_ms(start_t, 75);
> > +
> > +     enable_irq(mad->irq);
> > +adc_retry:
> > +     reinit_completion(&mad->adc_complete);
> > +
> > +     /* wait for conversion to complete */
> > +     timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> > +     if (timeout == 0) {
> > +             ret = -ETIMEDOUT;
> > +             goto out_adc_conv;
> > +     } else if (timeout < 0) {
> > +             ret = -EINTR;
> > +             goto out_adc_conv;
> > +     }
> > +
> > +     ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > +     if (ret)
> > +             goto out_adc_conv;
> > +
> > +     /* check the current reported channel */
> > +     if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> > +             dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);
>
> This and the one below feel like error messages rather than debug ones.
>

We have two function "battery zero current voltage(ZCV)" and "TypeC
OTP" will auto run ADC at background.
ZCV_EN will run VBAT_ADC when TA plug in, TypeC OTP will run TS_ADC
when TypeC attach.
We need to check report channel for ADC report data match is our desire channel.

> > +             goto adc_retry;
> > +     }
> > +
> > +     if (!ktime_after(ktime_get(), predict_end_t)) {
> > +             dev_dbg(mad->dev, "time is not after one adc_conv_t\n");
>
> Does this actually happen? If feels like we are being a bit over protective
> here.  I'd definitely like to see a comment saying why this protection
> might be needed.
>

When ADC_EN and MT6360_CHANx_EN is enable, the channel x will keep
running again and again
I supposed to get immediate data which is generated after I start it.

When I disable ADC_CHANx_EN, the H/W logical ADC is still running.
If I run the same ADC immediately, I may get the old result about this channel.
MT6360 ADC typical conversation time is about 25ms.
So We need ignore which irq trigger below 25ms.

> > +             goto adc_retry;
> > +     }
> > +
> > +     value = (rpt[1] << 8) | rpt[2];
> > +
> > +     ret = mt6360_adc_convert_processed_val(mad, channel, &value);
> > +     if (ret)
> > +             goto out_adc_conv;
> > +
> > +     *val = value;
> > +     ret = IIO_VAL_INT;
> > +
> > +out_adc_conv:
> > +     disable_irq(mad->irq);
> > +     adc_enable = MT6360_ADCEN_MASK;
> > +     adc_enable = cpu_to_be16(adc_enable);
> > +     regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > +     mad->last_off_timestamps[channel] = ktime_get();
> > +     /* set prefer channel to 0xf */
> > +     regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > +                        0xF << MT6360_PREFERCH_SHFT);
> > +out_adc:
> > +     mutex_unlock(&mad->adc_lock);
> > +
> > +     return ret;
> > +}
> > +
> > +static int mt6360_adc_read_raw(struct iio_dev *iio_dev, const struct iio_chan_spec *chan,
> > +                            int *val, int *val2, long mask)
> > +{
> > +     struct mt6360_adc_data *mad = iio_priv(iio_dev);
> > +
> > +     if (mask == IIO_CHAN_INFO_PROCESSED)
> > +             return mt6360_adc_read_processed(mad, chan->channel, val);
> > +
> > +     return -EINVAL;
> > +}
> > +
> > +static const struct iio_info mt6360_adc_iio_info = {
> > +     .read_raw = mt6360_adc_read_raw,
> > +};
> > +
> > +#define MT6360_ADC_CHAN(_idx, _type) {                               \
> > +     .type = _type,                                          \
> > +     .channel = MT6360_CHAN_##_idx,                          \
> > +     .scan_index = MT6360_CHAN_##_idx,                       \
> > +     .extend_name = #_idx,                                   \
> > +     .datasheet_name = #_idx,                                \
> > +     .scan_type =  {                                         \
> > +             .sign = 's',                                    \
> > +             .realbits = 32,                                 \
> > +             .storagebits = 32,                              \
> > +             .endianness = IIO_CPU,                          \
> > +     },                                                      \
> > +     .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),     \
> > +     .indexed = 1,                                           \
> > +}
> > +
> > +static const struct iio_chan_spec mt6360_adc_channels[] = {
> > +     MT6360_ADC_CHAN(USBID, IIO_VOLTAGE),
> > +     MT6360_ADC_CHAN(VBUSDIV5, IIO_VOLTAGE),
> > +     MT6360_ADC_CHAN(VBUSDIV2, IIO_VOLTAGE),
> > +     MT6360_ADC_CHAN(VSYS, IIO_VOLTAGE),
> > +     MT6360_ADC_CHAN(VBAT, IIO_VOLTAGE),
> > +     MT6360_ADC_CHAN(IBUS, IIO_CURRENT),
> > +     MT6360_ADC_CHAN(IBAT, IIO_CURRENT),
> > +     MT6360_ADC_CHAN(CHG_VDDP, IIO_VOLTAGE),
> > +     MT6360_ADC_CHAN(TEMP_JC, IIO_TEMP),
> > +     MT6360_ADC_CHAN(VREF_TS, IIO_VOLTAGE),
> > +     MT6360_ADC_CHAN(TS, IIO_VOLTAGE),
> > +     IIO_CHAN_SOFT_TIMESTAMP(MT6360_CHAN_MAX),
> > +};
> > +
> > +static irqreturn_t mt6360_pmu_adc_donei_handler(int irq, void *data)
> > +{
> > +     struct mt6360_adc_data *mad = iio_priv(data);
> > +
> > +     complete(&mad->adc_complete);
> > +     return IRQ_HANDLED;
> > +}
> > +
> ...
>
> > +
> > +static int mt6360_adc_probe(struct platform_device *pdev)
> > +{
> > +     struct mt6360_adc_data *mad;
> > +     struct iio_dev *indio_dev;
> > +     int ret;
> > +
> > +     indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*mad));
> > +     if (!indio_dev)
> > +             return -ENOMEM;
> > +
> > +     mad = iio_priv(indio_dev);
> > +     mad->dev = &pdev->dev;
> > +     init_completion(&mad->adc_complete);
> > +     mutex_init(&mad->adc_lock);
> > +
> > +     mad->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> > +     if (!mad->regmap) {
> > +             dev_err(&pdev->dev, "Failed to get parent regmap\n");
> > +             return -ENODEV;
> > +     }
> > +
> > +     ret = mt6360_adc_reset(mad);
> > +     if (ret < 0) {
> > +             dev_err(&pdev->dev, "Failed to reset adc\n");
> > +             return ret;
> > +     }
> > +
> > +     mad->irq = platform_get_irq_byname(pdev, "adc_donei");
> > +     if (mad->irq < 0) {
> > +             dev_err(&pdev->dev, "Failed to get adc_done irq\n");
> > +             return mad->irq;
> > +     }
> > +
> > +     irq_set_status_flags(mad->irq, IRQ_NOAUTOEN);
>
> As we are going to have a v5 anyway to clean up that endian warning,
> please could you add a comment to explain the need for IRQ_NOAUTOEN?
>

Same as above "Enable ADC will run again and again until clear
ADC__CHANx_EN bit"
So After I get the ADC result, I disable irq in order to handle only
oneshot data.

> > +     ret = devm_request_threaded_irq(&pdev->dev, mad->irq, NULL, mt6360_pmu_adc_donei_handler, 0,
> > +                                     "adc_donei", indio_dev);
> > +     if (ret) {
> > +             dev_err(&pdev->dev, "Failed to register adc_done irq\n");
> > +             return ret;
> > +     }
> > +
> > +     indio_dev->name = dev_name(&pdev->dev);
> > +     indio_dev->dev.parent = &pdev->dev;
> > +     indio_dev->info = &mt6360_adc_iio_info;
> > +     indio_dev->modes = INDIO_DIRECT_MODE;
> > +     indio_dev->channels = mt6360_adc_channels;
> > +     indio_dev->num_channels = ARRAY_SIZE(mt6360_adc_channels);
> > +
> > +     ret = devm_iio_triggered_buffer_setup(&pdev->dev, indio_dev, NULL,
> > +                                           mt6360_adc_trigger_handler, NULL);
> > +     if (ret) {
> > +             dev_err(&pdev->dev, "Failed to allocate iio trigger buffer\n");
> > +             return ret;
> > +     }
> > +
> > +     ret = devm_iio_device_register(&pdev->dev, indio_dev);
> > +     if (ret) {
> > +             dev_err(&pdev->dev, "Failed to register iio device\n");
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> ...

Andy Shevchenko Sept. 8, 2020, 7:43 a.m. UTC | #5

On Tue, Sep 8, 2020 at 9:19 AM Gene Chen <[e-mail]> wrote:
> Jonathan Cameron <[e-mail]> 於 2020年8月30日 週日 上午1:12寫道：
> > On Mon, 24 Aug 2020 17:06:24 +0800
> > Gene Chen <[e-mail]> wrote:

> > A few comments inline.  The big one centres on why we can't
> > expose the channels as _raw, _offset and _scale?
> >
>
> I think i have 3 reason for use real value,
> ADC is used to get real value rather than raw data which is not meaningful.
> And I can decide which formula needs apply according to different condition.
> Also the junction temperature channel _scale is floating point 1.05
> which is not easy to express.

It's easy to express. Like other values in IIO subsystem which are float.

Jonathan Cameron Sept. 8, 2020, 9:07 a.m. UTC | #6

On Tue, 8 Sep 2020 14:17:42 +0800
Gene Chen <[e-mail]> wrote:

> Jonathan Cameron <[e-mail]> 於 2020年8月30日 週日 上午1:12寫道：
> >
> > On Mon, 24 Aug 2020 17:06:24 +0800
> > Gene Chen <[e-mail]> wrote:
> >  
> > > From: Gene Chen <[e-mail]>
> > >
> > > Add MT6360 ADC driver include Charger Current, Voltage, and
> > > Temperature.
> > >
> > > Signed-off-by: Gene Chen <[e-mail]>  
> > Hi Gene,
> >
> > A few comments inline.  The big one centres on why we can't
> > expose the channels as _raw, _offset and _scale?
> >  
> 
> I think i have 3 reason for use real value,
> ADC is used to get real value rather than raw data which is not meaningful.
> And I can decide which formula needs apply according to different condition.
> Also the junction temperature channel _scale is floating point 1.05
> which is not easy to express.

See below.

> 
> > Thanks,
> >
> > Jonathan
> >  
> > > ---
> > >  drivers/iio/adc/Kconfig      |  11 ++
> > >  drivers/iio/adc/Makefile     |   1 +
> > >  drivers/iio/adc/mt6360-adc.c | 366 +++++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 378 insertions(+)
> > >  create mode 100644 drivers/iio/adc/mt6360-adc.c
> > >
> > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > > index 66d9cc0..07dcea7 100644
> > > --- a/drivers/iio/adc/Kconfig
> > > +++ b/drivers/iio/adc/Kconfig
> > > @@ -703,6 +703,17 @@ config MCP3911
> > >         This driver can also be built as a module. If so, the module will be
> > >         called mcp3911.
> > >
> > > +config MEDIATEK_MT6360_ADC
> > > +     tristate "Mediatek MT6360 ADC Part"
> > > +     depends on MFD_MT6360
> > > +     select IIO_BUFFER
> > > +     select IIO_TRIGGERED_BUFFER
> > > +     help
> > > +       Say Y here to enable MT6360 ADC Part.
> > > +       Integrated for System Monitoring include
> > > +       Charger and Battery Current, Voltage and
> > > +       Temperature
> > > +
> > >  config MEDIATEK_MT6577_AUXADC
> > >       tristate "MediaTek AUXADC driver"
> > >       depends on ARCH_MEDIATEK || COMPILE_TEST
> > > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > > index 90f94ad..5fca90a 100644
> > > --- a/drivers/iio/adc/Makefile
> > > +++ b/drivers/iio/adc/Makefile
> > > @@ -65,6 +65,7 @@ obj-$(CONFIG_MAX9611) += max9611.o
> > >  obj-$(CONFIG_MCP320X) += mcp320x.o
> > >  obj-$(CONFIG_MCP3422) += mcp3422.o
> > >  obj-$(CONFIG_MCP3911) += mcp3911.o
> > > +obj-$(CONFIG_MEDIATEK_MT6360_ADC) += mt6360-adc.o
> > >  obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o
> > >  obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
> > >  obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
> > > diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c
> > > new file mode 100644
> > > index 0000000..5eed812
> > > --- /dev/null
> > > +++ b/drivers/iio/adc/mt6360-adc.c
> > > @@ -0,0 +1,366 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (c) 2020 MediaTek Inc.
> > > + *
> > > + * Author: Gene Chen <[e-mail]>
> > > + */
> > > +
> > > +#include <linux/completion.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/iio/buffer.h>
> > > +#include <linux/iio/iio.h>
> > > +#include <linux/iio/trigger_consumer.h>
> > > +#include <linux/iio/triggered_buffer.h>
> > > +#include <linux/irq.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/ktime.h>
> > > +#include <linux/module.h>
> > > +#include <linux/mutex.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#define MT6360_REG_PMUCHGCTRL3       0x313
> > > +#define MT6360_REG_PMUADCCFG 0x356
> > > +#define MT6360_REG_PMUADCRPT1        0x35A
> > > +
> > > +/* PMUCHGCTRL3 0x313 */
> > > +#define MT6360_AICR_MASK     0xFC
> > > +#define MT6360_AICR_SHFT     2
> > > +#define MT6360_AICR_400MA    0x6
> > > +/* PMUADCCFG 0x356 */
> > > +#define MT6360_ADCEN_MASK    0x8000
> > > +/* PMUADCRPT1 0x35A */
> > > +#define MT6360_PREFERCH_MASK 0xF0
> > > +#define MT6360_PREFERCH_SHFT 4
> > > +#define MT6360_RPTCH_MASK    0x0F
> > > +
> > > +enum {
> > > +     MT6360_CHAN_USBID = 0,
> > > +     MT6360_CHAN_VBUSDIV5,
> > > +     MT6360_CHAN_VBUSDIV2,
> > > +     MT6360_CHAN_VSYS,
> > > +     MT6360_CHAN_VBAT,
> > > +     MT6360_CHAN_IBUS,
> > > +     MT6360_CHAN_IBAT,
> > > +     MT6360_CHAN_CHG_VDDP,
> > > +     MT6360_CHAN_TEMP_JC,
> > > +     MT6360_CHAN_VREF_TS,
> > > +     MT6360_CHAN_TS,
> > > +     MT6360_CHAN_MAX,
> > > +};
> > > +
> > > +struct mt6360_adc_data {
> > > +     struct device *dev;
> > > +     struct regmap *regmap;
> > > +     struct completion adc_complete;
> > > +     struct mutex adc_lock;
> > > +     ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > > +     int irq;
> > > +};
> > > +
> > > +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> > > +{
> > > +     return ((val * multiplier) + offset) / divisor;  
> >
> > Why could we not report these values to userspace or consumer drivers and let
> > them deal with the conversion if they actually needed it?
> > Mapping this to
> >
> > (val + new_offset) * multiplier would be a little messy, but not too bad.
> >
> > The advantage would be that we would then be providing the data needed
> > to get real units for values read from the buffers without having to
> > do all the maths in kernel (without access to floating point).
> >
> >  
> 
> As above, if I use formula "(val + new_offset) * multiplier",
> the junction temperature channel multiplier will be floating point
> 1.05, i don't know how to express.

As Andy mentioned, we do this all over the place.
IIO_VAL_INT_PLUS_MICRO

The key is that we want to push the burden of doing this maths to the user
not the source.

Often what is actually of interest is whether a temperature passed a threshold.
In that case, you can transform the threshold into the units of the ADC (so the
reverse directly to you would do with processed data) and only have to do the
maths once per change of the threshold instead of for every sample.

There are helper functions to do the maths for you, should you actually
need SI units.

> 
> > > +}
> > > +
> > > +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> > > +{
> > > +     unsigned int regval = 0;
> > > +     const struct converter {
> > > +             int multiplier;
> > > +             int offset;
> > > +             int divisor;
> > > +     } adc_converter[MT6360_CHAN_MAX] = {
> > > +             { 1250, 0, 1}, /* USBID */
> > > +             { 6250, 0, 1}, /* VBUSDIV5 */
> > > +             { 2500, 0, 1}, /* VBUSDIV2 */
> > > +             { 1250, 0, 1}, /* VSYS */
> > > +             { 1250, 0, 1}, /* VBAT */
> > > +             { 2500, 0, 1}, /* IBUS */
> > > +             { 2500, 0, 1}, /* IBAT */
> > > +             { 1250, 0, 1}, /* CHG_VDDP */
> > > +             { 105, -8000, 100}, /* TEMP_JC */
> > > +             { 1250, 0, 1}, /* VREF_TS */
> > > +             { 1250, 0, 1}, /* TS */
> > > +     }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> > > +     int ret;
> > > +
> > > +     sel_converter = adc_converter + chan_idx;
> > > +     if (chan_idx == MT6360_CHAN_IBUS) {
> > > +             /* ibus chan will be affected by aicr config */
> > > +             /* if aicr < 400, apply the special ibus converter */
> > > +             ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > > +             if (ret)
> > > +                     return ret;
> > > +
> > > +             regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > > +             if (regval < MT6360_AICR_400MA)
> > > +                     sel_converter = &sp_ibus_adc_converter;
> > > +     }
> > > +
> > > +     *val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> > > +                                     sel_converter->divisor);
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> > > +{
> > > +     u16 adc_enable;
> > > +     u8 rpt[3];
> > > +     ktime_t start_t, predict_end_t;
> > > +     long timeout;
> > > +     int value, ret;
> > > +
> > > +     mutex_lock(&mad->adc_lock);
> > > +
> > > +     /* select preferred channel that we want */
> > > +     ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > +                              channel << MT6360_PREFERCH_SHFT);
> > > +     if (ret)
> > > +             goto out_adc;
> > > +
> > > +     /* enable adc channel we want and adc_en */
> > > +     adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> > > +     adc_enable = cpu_to_be16(adc_enable);  
> >
> > Use a local be16 to store that. It will make it a little clearer
> > that we are doing something 'unusual' here.  Perhaps a comment on
> > why this odd code exists would also help?
> >  
> 
> ACK
> 
> > > +     ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > +     if (ret)
> > > +             goto out_adc;
> > > +
> > > +     start_t = ktime_get();
> > > +     predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> > > +
> > > +     if (ktime_after(start_t, predict_end_t))
> > > +             predict_end_t = ktime_add_ms(start_t, 25);
> > > +     else
> > > +             predict_end_t = ktime_add_ms(start_t, 75);
> > > +
> > > +     enable_irq(mad->irq);
> > > +adc_retry:
> > > +     reinit_completion(&mad->adc_complete);
> > > +
> > > +     /* wait for conversion to complete */
> > > +     timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> > > +     if (timeout == 0) {
> > > +             ret = -ETIMEDOUT;
> > > +             goto out_adc_conv;
> > > +     } else if (timeout < 0) {
> > > +             ret = -EINTR;
> > > +             goto out_adc_conv;
> > > +     }
> > > +
> > > +     ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > > +     if (ret)
> > > +             goto out_adc_conv;
> > > +
> > > +     /* check the current reported channel */
> > > +     if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> > > +             dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);  
> >
> > This and the one below feel like error messages rather than debug ones.
> >  
> 
> We have two function "battery zero current voltage(ZCV)" and "TypeC
> OTP" will auto run ADC at background.
> ZCV_EN will run VBAT_ADC when TA plug in, TypeC OTP will run TS_ADC
> when TypeC attach.
> We need to check report channel for ADC report data match is our desire channel.

So there is firmware messing with it underneath?  Oh goody.
Add a comment explaining this.

> 
> > > +             goto adc_retry;
> > > +     }
> > > +
> > > +     if (!ktime_after(ktime_get(), predict_end_t)) {
> > > +             dev_dbg(mad->dev, "time is not after one adc_conv_t\n");  
> >
> > Does this actually happen? If feels like we are being a bit over protective
> > here.  I'd definitely like to see a comment saying why this protection
> > might be needed.
> >  
> 
> When ADC_EN and MT6360_CHANx_EN is enable, the channel x will keep
> running again and again
> I supposed to get immediate data which is generated after I start it.

Just to check my understanding.

This is an edge triggered interrupt and it triggers every time a new sample
is taken.  Those samples are taken on a fixed frequency irrespective of whether
we have read the previous one?

> 
> When I disable ADC_CHANx_EN, the H/W logical ADC is still running.
> If I run the same ADC immediately, I may get the old result about this channel.
> MT6360 ADC typical conversation time is about 25ms.
> So We need ignore which irq trigger below 25ms.

Normal trick for this sort of case is to just not use the interrupt.
Just read after 25+delta msecs and you are guaranteed to get the right answer.


> 
> > > +             goto adc_retry;
> > > +     }
> > > +
> > > +     value = (rpt[1] << 8) | rpt[2];
> > > +
> > > +     ret = mt6360_adc_convert_processed_val(mad, channel, &value);
> > > +     if (ret)
> > > +             goto out_adc_conv;
> > > +
> > > +     *val = value;
> > > +     ret = IIO_VAL_INT;
> > > +
> > > +out_adc_conv:
> > > +     disable_irq(mad->irq);
> > > +     adc_enable = MT6360_ADCEN_MASK;
> > > +     adc_enable = cpu_to_be16(adc_enable);
> > > +     regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > +     mad->last_off_timestamps[channel] = ktime_get();
> > > +     /* set prefer channel to 0xf */
> > > +     regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > +                        0xF << MT6360_PREFERCH_SHFT);
> > > +out_adc:
> > > +     mutex_unlock(&mad->adc_lock);
> > > +
> > > +     return ret;
> > > +}
> > > +
> > > +static int mt6360_adc_read_raw(struct iio_dev *iio_dev, const struct iio_chan_spec *chan,
> > > +                            int *val, int *val2, long mask)
> > > +{
> > > +     struct mt6360_adc_data *mad = iio_priv(iio_dev);
> > > +
> > > +     if (mask == IIO_CHAN_INFO_PROCESSED)
> > > +             return mt6360_adc_read_processed(mad, chan->channel, val);
> > > +
> > > +     return -EINVAL;
> > > +}
> > > +
> > > +static const struct iio_info mt6360_adc_iio_info = {
> > > +     .read_raw = mt6360_adc_read_raw,
> > > +};
> > > +
> > > +#define MT6360_ADC_CHAN(_idx, _type) {                               \
> > > +     .type = _type,                                          \
> > > +     .channel = MT6360_CHAN_##_idx,                          \
> > > +     .scan_index = MT6360_CHAN_##_idx,                       \
> > > +     .extend_name = #_idx,                                   \
> > > +     .datasheet_name = #_idx,                                \
> > > +     .scan_type =  {                                         \
> > > +             .sign = 's',                                    \
> > > +             .realbits = 32,                                 \
> > > +             .storagebits = 32,                              \
> > > +             .endianness = IIO_CPU,                          \
> > > +     },                                                      \
> > > +     .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),     \
> > > +     .indexed = 1,                                           \
> > > +}
> > > +
> > > +static const struct iio_chan_spec mt6360_adc_channels[] = {
> > > +     MT6360_ADC_CHAN(USBID, IIO_VOLTAGE),
> > > +     MT6360_ADC_CHAN(VBUSDIV5, IIO_VOLTAGE),
> > > +     MT6360_ADC_CHAN(VBUSDIV2, IIO_VOLTAGE),
> > > +     MT6360_ADC_CHAN(VSYS, IIO_VOLTAGE),
> > > +     MT6360_ADC_CHAN(VBAT, IIO_VOLTAGE),
> > > +     MT6360_ADC_CHAN(IBUS, IIO_CURRENT),
> > > +     MT6360_ADC_CHAN(IBAT, IIO_CURRENT),
> > > +     MT6360_ADC_CHAN(CHG_VDDP, IIO_VOLTAGE),
> > > +     MT6360_ADC_CHAN(TEMP_JC, IIO_TEMP),
> > > +     MT6360_ADC_CHAN(VREF_TS, IIO_VOLTAGE),
> > > +     MT6360_ADC_CHAN(TS, IIO_VOLTAGE),
> > > +     IIO_CHAN_SOFT_TIMESTAMP(MT6360_CHAN_MAX),
> > > +};
> > > +
> > > +static irqreturn_t mt6360_pmu_adc_donei_handler(int irq, void *data)
> > > +{
> > > +     struct mt6360_adc_data *mad = iio_priv(data);
> > > +
> > > +     complete(&mad->adc_complete);
> > > +     return IRQ_HANDLED;
> > > +}
> > > +  
> > ...
> >  
> > > +
> > > +static int mt6360_adc_probe(struct platform_device *pdev)
> > > +{
> > > +     struct mt6360_adc_data *mad;
> > > +     struct iio_dev *indio_dev;
> > > +     int ret;
> > > +
> > > +     indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*mad));
> > > +     if (!indio_dev)
> > > +             return -ENOMEM;
> > > +
> > > +     mad = iio_priv(indio_dev);
> > > +     mad->dev = &pdev->dev;
> > > +     init_completion(&mad->adc_complete);
> > > +     mutex_init(&mad->adc_lock);
> > > +
> > > +     mad->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> > > +     if (!mad->regmap) {
> > > +             dev_err(&pdev->dev, "Failed to get parent regmap\n");
> > > +             return -ENODEV;
> > > +     }
> > > +
> > > +     ret = mt6360_adc_reset(mad);
> > > +     if (ret < 0) {
> > > +             dev_err(&pdev->dev, "Failed to reset adc\n");
> > > +             return ret;
> > > +     }
> > > +
> > > +     mad->irq = platform_get_irq_byname(pdev, "adc_donei");
> > > +     if (mad->irq < 0) {
> > > +             dev_err(&pdev->dev, "Failed to get adc_done irq\n");
> > > +             return mad->irq;
> > > +     }
> > > +
> > > +     irq_set_status_flags(mad->irq, IRQ_NOAUTOEN);  
> >
> > As we are going to have a v5 anyway to clean up that endian warning,
> > please could you add a comment to explain the need for IRQ_NOAUTOEN?
> >  
> 
> Same as above "Enable ADC will run again and again until clear
> ADC__CHANx_EN bit"
> So After I get the ADC result, I disable irq in order to handle only
> oneshot data.

As mentioned a above I suspect you may be better off just not using
the interrupt at all.

> 
> > > +     ret = devm_request_threaded_irq(&pdev->dev, mad->irq, NULL, mt6360_pmu_adc_donei_handler, 0,
> > > +                                     "adc_donei", indio_dev);
> > > +     if (ret) {
> > > +             dev_err(&pdev->dev, "Failed to register adc_done irq\n");
> > > +             return ret;
> > > +     }
> > > +
> > > +     indio_dev->name = dev_name(&pdev->dev);
> > > +     indio_dev->dev.parent = &pdev->dev;
> > > +     indio_dev->info = &mt6360_adc_iio_info;
> > > +     indio_dev->modes = INDIO_DIRECT_MODE;
> > > +     indio_dev->channels = mt6360_adc_channels;
> > > +     indio_dev->num_channels = ARRAY_SIZE(mt6360_adc_channels);
> > > +
> > > +     ret = devm_iio_triggered_buffer_setup(&pdev->dev, indio_dev, NULL,
> > > +                                           mt6360_adc_trigger_handler, NULL);
> > > +     if (ret) {
> > > +             dev_err(&pdev->dev, "Failed to allocate iio trigger buffer\n");
> > > +             return ret;
> > > +     }
> > > +
> > > +     ret = devm_iio_device_register(&pdev->dev, indio_dev);
> > > +     if (ret) {
> > > +             dev_err(&pdev->dev, "Failed to register iio device\n");
> > > +             return ret;
> > > +     }
> > > +
> > > +     return 0;
> > > +}  
> > ...

Gene Chen Sept. 8, 2020, 11:08 a.m. UTC | #7

Jonathan Cameron <[e-mail]> 於 2020年9月8日 週二 下午5:08寫道：
>
> On Tue, 8 Sep 2020 14:17:42 +0800
> Gene Chen <[e-mail]> wrote:
>
> > Jonathan Cameron <[e-mail]> 於 2020年8月30日 週日 上午1:12寫道：
> > >
> > > On Mon, 24 Aug 2020 17:06:24 +0800
> > > Gene Chen <[e-mail]> wrote:
> > >
> > > > From: Gene Chen <[e-mail]>
> > > >
> > > > Add MT6360 ADC driver include Charger Current, Voltage, and
> > > > Temperature.
> > > >
> > > > Signed-off-by: Gene Chen <[e-mail]>
> > > Hi Gene,
> > >
> > > A few comments inline.  The big one centres on why we can't
> > > expose the channels as _raw, _offset and _scale?
> > >
> >
> > I think i have 3 reason for use real value,
> > ADC is used to get real value rather than raw data which is not meaningful.
> > And I can decide which formula needs apply according to different condition.
> > Also the junction temperature channel _scale is floating point 1.05
> > which is not easy to express.
>
> See below.
>
> >
> > > Thanks,
> > >
> > > Jonathan
> > >
> > > > ---
> > > >  drivers/iio/adc/Kconfig      |  11 ++
> > > >  drivers/iio/adc/Makefile     |   1 +
> > > >  drivers/iio/adc/mt6360-adc.c | 366 +++++++++++++++++++++++++++++++++++++++++++
> > > >  3 files changed, 378 insertions(+)
> > > >  create mode 100644 drivers/iio/adc/mt6360-adc.c
> > > >
> > > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > > > index 66d9cc0..07dcea7 100644
> > > > --- a/drivers/iio/adc/Kconfig
> > > > +++ b/drivers/iio/adc/Kconfig
> > > > @@ -703,6 +703,17 @@ config MCP3911
> > > >         This driver can also be built as a module. If so, the module will be
> > > >         called mcp3911.
> > > >
> > > > +config MEDIATEK_MT6360_ADC
> > > > +     tristate "Mediatek MT6360 ADC Part"
> > > > +     depends on MFD_MT6360
> > > > +     select IIO_BUFFER
> > > > +     select IIO_TRIGGERED_BUFFER
> > > > +     help
> > > > +       Say Y here to enable MT6360 ADC Part.
> > > > +       Integrated for System Monitoring include
> > > > +       Charger and Battery Current, Voltage and
> > > > +       Temperature
> > > > +
> > > >  config MEDIATEK_MT6577_AUXADC
> > > >       tristate "MediaTek AUXADC driver"
> > > >       depends on ARCH_MEDIATEK || COMPILE_TEST
> > > > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > > > index 90f94ad..5fca90a 100644
> > > > --- a/drivers/iio/adc/Makefile
> > > > +++ b/drivers/iio/adc/Makefile
> > > > @@ -65,6 +65,7 @@ obj-$(CONFIG_MAX9611) += max9611.o
> > > >  obj-$(CONFIG_MCP320X) += mcp320x.o
> > > >  obj-$(CONFIG_MCP3422) += mcp3422.o
> > > >  obj-$(CONFIG_MCP3911) += mcp3911.o
> > > > +obj-$(CONFIG_MEDIATEK_MT6360_ADC) += mt6360-adc.o
> > > >  obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o
> > > >  obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
> > > >  obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
> > > > diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c
> > > > new file mode 100644
> > > > index 0000000..5eed812
> > > > --- /dev/null
> > > > +++ b/drivers/iio/adc/mt6360-adc.c
> > > > @@ -0,0 +1,366 @@
> > > > +// SPDX-License-Identifier: GPL-2.0
> > > > +/*
> > > > + * Copyright (c) 2020 MediaTek Inc.
> > > > + *
> > > > + * Author: Gene Chen <[e-mail]>
> > > > + */
> > > > +
> > > > +#include <linux/completion.h>
> > > > +#include <linux/interrupt.h>
> > > > +#include <linux/iio/buffer.h>
> > > > +#include <linux/iio/iio.h>
> > > > +#include <linux/iio/trigger_consumer.h>
> > > > +#include <linux/iio/triggered_buffer.h>
> > > > +#include <linux/irq.h>
> > > > +#include <linux/kernel.h>
> > > > +#include <linux/ktime.h>
> > > > +#include <linux/module.h>
> > > > +#include <linux/mutex.h>
> > > > +#include <linux/platform_device.h>
> > > > +#include <linux/regmap.h>
> > > > +
> > > > +#define MT6360_REG_PMUCHGCTRL3       0x313
> > > > +#define MT6360_REG_PMUADCCFG 0x356
> > > > +#define MT6360_REG_PMUADCRPT1        0x35A
> > > > +
> > > > +/* PMUCHGCTRL3 0x313 */
> > > > +#define MT6360_AICR_MASK     0xFC
> > > > +#define MT6360_AICR_SHFT     2
> > > > +#define MT6360_AICR_400MA    0x6
> > > > +/* PMUADCCFG 0x356 */
> > > > +#define MT6360_ADCEN_MASK    0x8000
> > > > +/* PMUADCRPT1 0x35A */
> > > > +#define MT6360_PREFERCH_MASK 0xF0
> > > > +#define MT6360_PREFERCH_SHFT 4
> > > > +#define MT6360_RPTCH_MASK    0x0F
> > > > +
> > > > +enum {
> > > > +     MT6360_CHAN_USBID = 0,
> > > > +     MT6360_CHAN_VBUSDIV5,
> > > > +     MT6360_CHAN_VBUSDIV2,
> > > > +     MT6360_CHAN_VSYS,
> > > > +     MT6360_CHAN_VBAT,
> > > > +     MT6360_CHAN_IBUS,
> > > > +     MT6360_CHAN_IBAT,
> > > > +     MT6360_CHAN_CHG_VDDP,
> > > > +     MT6360_CHAN_TEMP_JC,
> > > > +     MT6360_CHAN_VREF_TS,
> > > > +     MT6360_CHAN_TS,
> > > > +     MT6360_CHAN_MAX,
> > > > +};
> > > > +
> > > > +struct mt6360_adc_data {
> > > > +     struct device *dev;
> > > > +     struct regmap *regmap;
> > > > +     struct completion adc_complete;
> > > > +     struct mutex adc_lock;
> > > > +     ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > > > +     int irq;
> > > > +};
> > > > +
> > > > +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> > > > +{
> > > > +     return ((val * multiplier) + offset) / divisor;
> > >
> > > Why could we not report these values to userspace or consumer drivers and let
> > > them deal with the conversion if they actually needed it?
> > > Mapping this to
> > >
> > > (val + new_offset) * multiplier would be a little messy, but not too bad.
> > >
> > > The advantage would be that we would then be providing the data needed
> > > to get real units for values read from the buffers without having to
> > > do all the maths in kernel (without access to floating point).
> > >
> > >
> >
> > As above, if I use formula "(val + new_offset) * multiplier",
> > the junction temperature channel multiplier will be floating point
> > 1.05, i don't know how to express.
>
> As Andy mentioned, we do this all over the place.
> IIO_VAL_INT_PLUS_MICRO
>
> The key is that we want to push the burden of doing this maths to the user
> not the source.

ACK.
Can I keep IIO_CHAN_INFO_PROCESSED function be reserved for user in
kernel space?

>
> Often what is actually of interest is whether a temperature passed a threshold.
> In that case, you can transform the threshold into the units of the ADC (so the
> reverse directly to you would do with processed data) and only have to do the
> maths once per change of the threshold instead of for every sample.
>
> There are helper functions to do the maths for you, should you actually
> need SI units.
>

ACK

> >
> > > > +}
> > > > +
> > > > +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> > > > +{
> > > > +     unsigned int regval = 0;
> > > > +     const struct converter {
> > > > +             int multiplier;
> > > > +             int offset;
> > > > +             int divisor;
> > > > +     } adc_converter[MT6360_CHAN_MAX] = {
> > > > +             { 1250, 0, 1}, /* USBID */
> > > > +             { 6250, 0, 1}, /* VBUSDIV5 */
> > > > +             { 2500, 0, 1}, /* VBUSDIV2 */
> > > > +             { 1250, 0, 1}, /* VSYS */
> > > > +             { 1250, 0, 1}, /* VBAT */
> > > > +             { 2500, 0, 1}, /* IBUS */
> > > > +             { 2500, 0, 1}, /* IBAT */
> > > > +             { 1250, 0, 1}, /* CHG_VDDP */
> > > > +             { 105, -8000, 100}, /* TEMP_JC */
> > > > +             { 1250, 0, 1}, /* VREF_TS */
> > > > +             { 1250, 0, 1}, /* TS */
> > > > +     }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> > > > +     int ret;
> > > > +
> > > > +     sel_converter = adc_converter + chan_idx;
> > > > +     if (chan_idx == MT6360_CHAN_IBUS) {
> > > > +             /* ibus chan will be affected by aicr config */
> > > > +             /* if aicr < 400, apply the special ibus converter */
> > > > +             ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > > > +             if (ret)
> > > > +                     return ret;
> > > > +
> > > > +             regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > > > +             if (regval < MT6360_AICR_400MA)
> > > > +                     sel_converter = &sp_ibus_adc_converter;
> > > > +     }
> > > > +
> > > > +     *val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> > > > +                                     sel_converter->divisor);
> > > > +
> > > > +     return 0;
> > > > +}
> > > > +
> > > > +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> > > > +{
> > > > +     u16 adc_enable;
> > > > +     u8 rpt[3];
> > > > +     ktime_t start_t, predict_end_t;
> > > > +     long timeout;
> > > > +     int value, ret;
> > > > +
> > > > +     mutex_lock(&mad->adc_lock);
> > > > +
> > > > +     /* select preferred channel that we want */
> > > > +     ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > > +                              channel << MT6360_PREFERCH_SHFT);
> > > > +     if (ret)
> > > > +             goto out_adc;
> > > > +
> > > > +     /* enable adc channel we want and adc_en */
> > > > +     adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> > > > +     adc_enable = cpu_to_be16(adc_enable);
> > >
> > > Use a local be16 to store that. It will make it a little clearer
> > > that we are doing something 'unusual' here.  Perhaps a comment on
> > > why this odd code exists would also help?
> > >
> >
> > ACK
> >
> > > > +     ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > > +     if (ret)
> > > > +             goto out_adc;
> > > > +
> > > > +     start_t = ktime_get();
> > > > +     predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> > > > +
> > > > +     if (ktime_after(start_t, predict_end_t))
> > > > +             predict_end_t = ktime_add_ms(start_t, 25);
> > > > +     else
> > > > +             predict_end_t = ktime_add_ms(start_t, 75);
> > > > +
> > > > +     enable_irq(mad->irq);
> > > > +adc_retry:
> > > > +     reinit_completion(&mad->adc_complete);
> > > > +
> > > > +     /* wait for conversion to complete */
> > > > +     timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> > > > +     if (timeout == 0) {
> > > > +             ret = -ETIMEDOUT;
> > > > +             goto out_adc_conv;
> > > > +     } else if (timeout < 0) {
> > > > +             ret = -EINTR;
> > > > +             goto out_adc_conv;
> > > > +     }
> > > > +
> > > > +     ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > > > +     if (ret)
> > > > +             goto out_adc_conv;
> > > > +
> > > > +     /* check the current reported channel */
> > > > +     if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> > > > +             dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);
> > >
> > > This and the one below feel like error messages rather than debug ones.
> > >
> >
> > We have two function "battery zero current voltage(ZCV)" and "TypeC
> > OTP" will auto run ADC at background.
> > ZCV_EN will run VBAT_ADC when TA plug in, TypeC OTP will run TS_ADC
> > when TypeC attach.
> > We need to check report channel for ADC report data match is our desire channel.
>
> So there is firmware messing with it underneath?  Oh goody.
> Add a comment explaining this.
>

ACK, I try to write a comment as below

        /*
         * There are two functions, ZCV and TypeC OTP, running ADC
VBAT and TS in background,
         * and ADC samples are taken on a fixed frequency no matter
read the previous one or not.
         * To avoid conflict need set minimum time threshold after
enable ADC and check report
         * channel is the same.
         * The worst case is run the same ADC twice and background
function is also running,
         * ADC conversion sequence is desire channel before start ADC,
background ADC, desire
         * channel after start ADC. So the minimum correct data is
three times of typical
         * conversion time.
         */

> >
> > > > +             goto adc_retry;
> > > > +     }
> > > > +
> > > > +     if (!ktime_after(ktime_get(), predict_end_t)) {
> > > > +             dev_dbg(mad->dev, "time is not after one adc_conv_t\n");
> > >
> > > Does this actually happen? If feels like we are being a bit over protective
> > > here.  I'd definitely like to see a comment saying why this protection
> > > might be needed.
> > >
> >
> > When ADC_EN and MT6360_CHANx_EN is enable, the channel x will keep
> > running again and again
> > I supposed to get immediate data which is generated after I start it.
>
> Just to check my understanding.
>
> This is an edge triggered interrupt and it triggers every time a new sample
> is taken.  Those samples are taken on a fixed frequency irrespective of whether
> we have read the previous one?
>

Yes.
I use LEVEL_LOW trigger in latest review MFD patch.

> >
> > When I disable ADC_CHANx_EN, the H/W logical ADC is still running.
> > If I run the same ADC immediately, I may get the old result about this channel.
> > MT6360 ADC typical conversation time is about 25ms.
> > So We need ignore which irq trigger below 25ms.
>
> Normal trick for this sort of case is to just not use the interrupt.
> Just read after 25+delta msecs and you are guaranteed to get the right answer.
>
>

ACK, I will try to use polling
Is the pseudocode correct?

mdelay(predict_end_t);
while (true) {
    read adc event is occured
    check report channel is the same
    if the same, read report ADC data and break while loop
    else msleep(per ADC conversion time)
}

> >
> > > > +             goto adc_retry;
> > > > +     }
> > > > +
> > > > +     value = (rpt[1] << 8) | rpt[2];
> > > > +
> > > > +     ret = mt6360_adc_convert_processed_val(mad, channel, &value);
> > > > +     if (ret)
> > > > +             goto out_adc_conv;
> > > > +
> > > > +     *val = value;
> > > > +     ret = IIO_VAL_INT;
> > > > +
> > > > +out_adc_conv:
> > > > +     disable_irq(mad->irq);
> > > > +     adc_enable = MT6360_ADCEN_MASK;
> > > > +     adc_enable = cpu_to_be16(adc_enable);
> > > > +     regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > > +     mad->last_off_timestamps[channel] = ktime_get();
> > > > +     /* set prefer channel to 0xf */
> > > > +     regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > > +                        0xF << MT6360_PREFERCH_SHFT);
> > > > +out_adc:
> > > > +     mutex_unlock(&mad->adc_lock);
> > > > +
> > > > +     return ret;
> > > > +}
> > > > +
> > > > +static int mt6360_adc_read_raw(struct iio_dev *iio_dev, const struct iio_chan_spec *chan,
> > > > +                            int *val, int *val2, long mask)
> > > > +{
> > > > +     struct mt6360_adc_data *mad = iio_priv(iio_dev);
> > > > +
> > > > +     if (mask == IIO_CHAN_INFO_PROCESSED)
> > > > +             return mt6360_adc_read_processed(mad, chan->channel, val);
> > > > +
> > > > +     return -EINVAL;
> > > > +}
> > > > +
> > > > +static const struct iio_info mt6360_adc_iio_info = {
> > > > +     .read_raw = mt6360_adc_read_raw,
> > > > +};
> > > > +
> > > > +#define MT6360_ADC_CHAN(_idx, _type) {                               \
> > > > +     .type = _type,                                          \
> > > > +     .channel = MT6360_CHAN_##_idx,                          \
> > > > +     .scan_index = MT6360_CHAN_##_idx,                       \
> > > > +     .extend_name = #_idx,                                   \
> > > > +     .datasheet_name = #_idx,                                \
> > > > +     .scan_type =  {                                         \
> > > > +             .sign = 's',                                    \
> > > > +             .realbits = 32,                                 \
> > > > +             .storagebits = 32,                              \
> > > > +             .endianness = IIO_CPU,                          \
> > > > +     },                                                      \
> > > > +     .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),     \
> > > > +     .indexed = 1,                                           \
> > > > +}
> > > > +
> > > > +static const struct iio_chan_spec mt6360_adc_channels[] = {
> > > > +     MT6360_ADC_CHAN(USBID, IIO_VOLTAGE),
> > > > +     MT6360_ADC_CHAN(VBUSDIV5, IIO_VOLTAGE),
> > > > +     MT6360_ADC_CHAN(VBUSDIV2, IIO_VOLTAGE),
> > > > +     MT6360_ADC_CHAN(VSYS, IIO_VOLTAGE),
> > > > +     MT6360_ADC_CHAN(VBAT, IIO_VOLTAGE),
> > > > +     MT6360_ADC_CHAN(IBUS, IIO_CURRENT),
> > > > +     MT6360_ADC_CHAN(IBAT, IIO_CURRENT),
> > > > +     MT6360_ADC_CHAN(CHG_VDDP, IIO_VOLTAGE),
> > > > +     MT6360_ADC_CHAN(TEMP_JC, IIO_TEMP),
> > > > +     MT6360_ADC_CHAN(VREF_TS, IIO_VOLTAGE),
> > > > +     MT6360_ADC_CHAN(TS, IIO_VOLTAGE),
> > > > +     IIO_CHAN_SOFT_TIMESTAMP(MT6360_CHAN_MAX),
> > > > +};
> > > > +
> > > > +static irqreturn_t mt6360_pmu_adc_donei_handler(int irq, void *data)
> > > > +{
> > > > +     struct mt6360_adc_data *mad = iio_priv(data);
> > > > +
> > > > +     complete(&mad->adc_complete);
> > > > +     return IRQ_HANDLED;
> > > > +}
> > > > +
> > > ...
> > >
> > > > +
> > > > +static int mt6360_adc_probe(struct platform_device *pdev)
> > > > +{
> > > > +     struct mt6360_adc_data *mad;
> > > > +     struct iio_dev *indio_dev;
> > > > +     int ret;
> > > > +
> > > > +     indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*mad));
> > > > +     if (!indio_dev)
> > > > +             return -ENOMEM;
> > > > +
> > > > +     mad = iio_priv(indio_dev);
> > > > +     mad->dev = &pdev->dev;
> > > > +     init_completion(&mad->adc_complete);
> > > > +     mutex_init(&mad->adc_lock);
> > > > +
> > > > +     mad->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> > > > +     if (!mad->regmap) {
> > > > +             dev_err(&pdev->dev, "Failed to get parent regmap\n");
> > > > +             return -ENODEV;
> > > > +     }
> > > > +
> > > > +     ret = mt6360_adc_reset(mad);
> > > > +     if (ret < 0) {
> > > > +             dev_err(&pdev->dev, "Failed to reset adc\n");
> > > > +             return ret;
> > > > +     }
> > > > +
> > > > +     mad->irq = platform_get_irq_byname(pdev, "adc_donei");
> > > > +     if (mad->irq < 0) {
> > > > +             dev_err(&pdev->dev, "Failed to get adc_done irq\n");
> > > > +             return mad->irq;
> > > > +     }
> > > > +
> > > > +     irq_set_status_flags(mad->irq, IRQ_NOAUTOEN);
> > >
> > > As we are going to have a v5 anyway to clean up that endian warning,
> > > please could you add a comment to explain the need for IRQ_NOAUTOEN?
> > >
> >
> > Same as above "Enable ADC will run again and again until clear
> > ADC__CHANx_EN bit"
> > So After I get the ADC result, I disable irq in order to handle only
> > oneshot data.
>
> As mentioned a above I suspect you may be better off just not using
> the interrupt at all.
>

ACK, I try to fixed by polling ADC event.

> >
> > > > +     ret = devm_request_threaded_irq(&pdev->dev, mad->irq, NULL, mt6360_pmu_adc_donei_handler, 0,
> > > > +                                     "adc_donei", indio_dev);
> > > > +     if (ret) {
> > > > +             dev_err(&pdev->dev, "Failed to register adc_done irq\n");
> > > > +             return ret;
> > > > +     }
> > > > +
> > > > +     indio_dev->name = dev_name(&pdev->dev);
> > > > +     indio_dev->dev.parent = &pdev->dev;
> > > > +     indio_dev->info = &mt6360_adc_iio_info;
> > > > +     indio_dev->modes = INDIO_DIRECT_MODE;
> > > > +     indio_dev->channels = mt6360_adc_channels;
> > > > +     indio_dev->num_channels = ARRAY_SIZE(mt6360_adc_channels);
> > > > +
> > > > +     ret = devm_iio_triggered_buffer_setup(&pdev->dev, indio_dev, NULL,
> > > > +                                           mt6360_adc_trigger_handler, NULL);
> > > > +     if (ret) {
> > > > +             dev_err(&pdev->dev, "Failed to allocate iio trigger buffer\n");
> > > > +             return ret;
> > > > +     }
> > > > +
> > > > +     ret = devm_iio_device_register(&pdev->dev, indio_dev);
> > > > +     if (ret) {
> > > > +             dev_err(&pdev->dev, "Failed to register iio device\n");
> > > > +             return ret;
> > > > +     }
> > > > +
> > > > +     return 0;
> > > > +}
> > > ...
>
>

Jonathan Cameron Sept. 8, 2020, 12:58 p.m. UTC | #8

...

> > > > > +#include <linux/completion.h>
> > > > > +#include <linux/interrupt.h>
> > > > > +#include <linux/iio/buffer.h>
> > > > > +#include <linux/iio/iio.h>
> > > > > +#include <linux/iio/trigger_consumer.h>
> > > > > +#include <linux/iio/triggered_buffer.h>
> > > > > +#include <linux/irq.h>
> > > > > +#include <linux/kernel.h>
> > > > > +#include <linux/ktime.h>
> > > > > +#include <linux/module.h>
> > > > > +#include <linux/mutex.h>
> > > > > +#include <linux/platform_device.h>
> > > > > +#include <linux/regmap.h>
> > > > > +
> > > > > +#define MT6360_REG_PMUCHGCTRL3       0x313
> > > > > +#define MT6360_REG_PMUADCCFG 0x356
> > > > > +#define MT6360_REG_PMUADCRPT1        0x35A
> > > > > +
> > > > > +/* PMUCHGCTRL3 0x313 */
> > > > > +#define MT6360_AICR_MASK     0xFC
> > > > > +#define MT6360_AICR_SHFT     2
> > > > > +#define MT6360_AICR_400MA    0x6
> > > > > +/* PMUADCCFG 0x356 */
> > > > > +#define MT6360_ADCEN_MASK    0x8000
> > > > > +/* PMUADCRPT1 0x35A */
> > > > > +#define MT6360_PREFERCH_MASK 0xF0
> > > > > +#define MT6360_PREFERCH_SHFT 4
> > > > > +#define MT6360_RPTCH_MASK    0x0F
> > > > > +
> > > > > +enum {
> > > > > +     MT6360_CHAN_USBID = 0,
> > > > > +     MT6360_CHAN_VBUSDIV5,
> > > > > +     MT6360_CHAN_VBUSDIV2,
> > > > > +     MT6360_CHAN_VSYS,
> > > > > +     MT6360_CHAN_VBAT,
> > > > > +     MT6360_CHAN_IBUS,
> > > > > +     MT6360_CHAN_IBAT,
> > > > > +     MT6360_CHAN_CHG_VDDP,
> > > > > +     MT6360_CHAN_TEMP_JC,
> > > > > +     MT6360_CHAN_VREF_TS,
> > > > > +     MT6360_CHAN_TS,
> > > > > +     MT6360_CHAN_MAX,
> > > > > +};
> > > > > +
> > > > > +struct mt6360_adc_data {
> > > > > +     struct device *dev;
> > > > > +     struct regmap *regmap;
> > > > > +     struct completion adc_complete;
> > > > > +     struct mutex adc_lock;
> > > > > +     ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > > > > +     int irq;
> > > > > +};
> > > > > +
> > > > > +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> > > > > +{
> > > > > +     return ((val * multiplier) + offset) / divisor;  
> > > >
> > > > Why could we not report these values to userspace or consumer drivers and let
> > > > them deal with the conversion if they actually needed it?
> > > > Mapping this to
> > > >
> > > > (val + new_offset) * multiplier would be a little messy, but not too bad.
> > > >
> > > > The advantage would be that we would then be providing the data needed
> > > > to get real units for values read from the buffers without having to
> > > > do all the maths in kernel (without access to floating point).
> > > >
> > > >  
> > >
> > > As above, if I use formula "(val + new_offset) * multiplier",
> > > the junction temperature channel multiplier will be floating point
> > > 1.05, i don't know how to express.  
> >
> > As Andy mentioned, we do this all over the place.
> > IIO_VAL_INT_PLUS_MICRO
> >
> > The key is that we want to push the burden of doing this maths to the user
> > not the source.  
> 
> ACK.
> Can I keep IIO_CHAN_INFO_PROCESSED function be reserved for user in
> kernel space?
> 

No. We have utility functions that will apply the multiplier as needed so
there is no significant advantage in doing this and it won't be consistent
with the majority of other drivers. 

> >
> > Often what is actually of interest is whether a temperature passed a threshold.
> > In that case, you can transform the threshold into the units of the ADC (so the
> > reverse directly to you would do with processed data) and only have to do the
> > maths once per change of the threshold instead of for every sample.
> >
> > There are helper functions to do the maths for you, should you actually
> > need SI units.
> >  
> 
> ACK
> 
> > >  
> > > > > +}
> > > > > +
> > > > > +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> > > > > +{
> > > > > +     unsigned int regval = 0;
> > > > > +     const struct converter {
> > > > > +             int multiplier;
> > > > > +             int offset;
> > > > > +             int divisor;
> > > > > +     } adc_converter[MT6360_CHAN_MAX] = {
> > > > > +             { 1250, 0, 1}, /* USBID */
> > > > > +             { 6250, 0, 1}, /* VBUSDIV5 */
> > > > > +             { 2500, 0, 1}, /* VBUSDIV2 */
> > > > > +             { 1250, 0, 1}, /* VSYS */
> > > > > +             { 1250, 0, 1}, /* VBAT */
> > > > > +             { 2500, 0, 1}, /* IBUS */
> > > > > +             { 2500, 0, 1}, /* IBAT */
> > > > > +             { 1250, 0, 1}, /* CHG_VDDP */
> > > > > +             { 105, -8000, 100}, /* TEMP_JC */
> > > > > +             { 1250, 0, 1}, /* VREF_TS */
> > > > > +             { 1250, 0, 1}, /* TS */
> > > > > +     }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> > > > > +     int ret;
> > > > > +
> > > > > +     sel_converter = adc_converter + chan_idx;
> > > > > +     if (chan_idx == MT6360_CHAN_IBUS) {
> > > > > +             /* ibus chan will be affected by aicr config */
> > > > > +             /* if aicr < 400, apply the special ibus converter */
> > > > > +             ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > > > > +             if (ret)
> > > > > +                     return ret;
> > > > > +
> > > > > +             regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > > > > +             if (regval < MT6360_AICR_400MA)
> > > > > +                     sel_converter = &sp_ibus_adc_converter;
> > > > > +     }
> > > > > +
> > > > > +     *val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> > > > > +                                     sel_converter->divisor);
> > > > > +
> > > > > +     return 0;
> > > > > +}
> > > > > +
> > > > > +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> > > > > +{
> > > > > +     u16 adc_enable;
> > > > > +     u8 rpt[3];
> > > > > +     ktime_t start_t, predict_end_t;
> > > > > +     long timeout;
> > > > > +     int value, ret;
> > > > > +
> > > > > +     mutex_lock(&mad->adc_lock);
> > > > > +
> > > > > +     /* select preferred channel that we want */
> > > > > +     ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > > > +                              channel << MT6360_PREFERCH_SHFT);
> > > > > +     if (ret)
> > > > > +             goto out_adc;
> > > > > +
> > > > > +     /* enable adc channel we want and adc_en */
> > > > > +     adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> > > > > +     adc_enable = cpu_to_be16(adc_enable);  
> > > >
> > > > Use a local be16 to store that. It will make it a little clearer
> > > > that we are doing something 'unusual' here.  Perhaps a comment on
> > > > why this odd code exists would also help?
> > > >  
> > >
> > > ACK
> > >  
> > > > > +     ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > > > +     if (ret)
> > > > > +             goto out_adc;
> > > > > +
> > > > > +     start_t = ktime_get();
> > > > > +     predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> > > > > +
> > > > > +     if (ktime_after(start_t, predict_end_t))
> > > > > +             predict_end_t = ktime_add_ms(start_t, 25);
> > > > > +     else
> > > > > +             predict_end_t = ktime_add_ms(start_t, 75);
> > > > > +
> > > > > +     enable_irq(mad->irq);
> > > > > +adc_retry:
> > > > > +     reinit_completion(&mad->adc_complete);
> > > > > +
> > > > > +     /* wait for conversion to complete */
> > > > > +     timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> > > > > +     if (timeout == 0) {
> > > > > +             ret = -ETIMEDOUT;
> > > > > +             goto out_adc_conv;
> > > > > +     } else if (timeout < 0) {
> > > > > +             ret = -EINTR;
> > > > > +             goto out_adc_conv;
> > > > > +     }
> > > > > +
> > > > > +     ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > > > > +     if (ret)
> > > > > +             goto out_adc_conv;
> > > > > +
> > > > > +     /* check the current reported channel */
> > > > > +     if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> > > > > +             dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);  
> > > >
> > > > This and the one below feel like error messages rather than debug ones.
> > > >  
> > >
> > > We have two function "battery zero current voltage(ZCV)" and "TypeC
> > > OTP" will auto run ADC at background.
> > > ZCV_EN will run VBAT_ADC when TA plug in, TypeC OTP will run TS_ADC
> > > when TypeC attach.
> > > We need to check report channel for ADC report data match is our desire channel.  
> >
> > So there is firmware messing with it underneath?  Oh goody.
> > Add a comment explaining this.
> >  
> 
> ACK, I try to write a comment as below
> 
>         /*
>          * There are two functions, ZCV and TypeC OTP, running ADC
> VBAT and TS in background,
>          * and ADC samples are taken on a fixed frequency no matter
> read the previous one or not.
>          * To avoid conflict need set minimum time threshold after
> enable ADC and check report
>          * channel is the same.
>          * The worst case is run the same ADC twice and background
> function is also running,
>          * ADC conversion sequence is desire channel before start ADC,
> background ADC, desire
>          * channel after start ADC. So the minimum correct data is
> three times of typical
>          * conversion time.
>          */

Looks good.

> 
> > >  
> > > > > +             goto adc_retry;
> > > > > +     }
> > > > > +
> > > > > +     if (!ktime_after(ktime_get(), predict_end_t)) {
> > > > > +             dev_dbg(mad->dev, "time is not after one adc_conv_t\n");  
> > > >
> > > > Does this actually happen? If feels like we are being a bit over protective
> > > > here.  I'd definitely like to see a comment saying why this protection
> > > > might be needed.
> > > >  
> > >
> > > When ADC_EN and MT6360_CHANx_EN is enable, the channel x will keep
> > > running again and again
> > > I supposed to get immediate data which is generated after I start it.  
> >
> > Just to check my understanding.
> >
> > This is an edge triggered interrupt and it triggers every time a new sample
> > is taken.  Those samples are taken on a fixed frequency irrespective of whether
> > we have read the previous one?
> >  
> 
> Yes.
> I use LEVEL_LOW trigger in latest review MFD patch.

I'm not sure I follow that comment.  How can you do that if it's a repeating
edge trigger? 

> 
> > >
> > > When I disable ADC_CHANx_EN, the H/W logical ADC is still running.
> > > If I run the same ADC immediately, I may get the old result about this channel.
> > > MT6360 ADC typical conversation time is about 25ms.
> > > So We need ignore which irq trigger below 25ms.  
> >
> > Normal trick for this sort of case is to just not use the interrupt.
> > Just read after 25+delta msecs and you are guaranteed to get the right answer.
> >
> >  
> 
> ACK, I will try to use polling
> Is the pseudocode correct?
> 
> mdelay(predict_end_t);
> while (true) {
>     read adc event is occured
>     check report channel is the same
>     if the same, read report ADC data and break while loop
>     else msleep(per ADC conversion time)
> }

Looks correct to me.  We should 'know' the event has happened but
still need to check the channel is the expected one.

...

Gene Chen Sept. 8, 2020, 11:39 p.m. UTC | #9

Jonathan Cameron <[e-mail]> 於 2020年9月8日 週二 下午9:00寫道：
>
> ...
>
> > > > > > +#include <linux/completion.h>
> > > > > > +#include <linux/interrupt.h>
> > > > > > +#include <linux/iio/buffer.h>
> > > > > > +#include <linux/iio/iio.h>
> > > > > > +#include <linux/iio/trigger_consumer.h>
> > > > > > +#include <linux/iio/triggered_buffer.h>
> > > > > > +#include <linux/irq.h>
> > > > > > +#include <linux/kernel.h>
> > > > > > +#include <linux/ktime.h>
> > > > > > +#include <linux/module.h>
> > > > > > +#include <linux/mutex.h>
> > > > > > +#include <linux/platform_device.h>
> > > > > > +#include <linux/regmap.h>
> > > > > > +
> > > > > > +#define MT6360_REG_PMUCHGCTRL3       0x313
> > > > > > +#define MT6360_REG_PMUADCCFG 0x356
> > > > > > +#define MT6360_REG_PMUADCRPT1        0x35A
> > > > > > +
> > > > > > +/* PMUCHGCTRL3 0x313 */
> > > > > > +#define MT6360_AICR_MASK     0xFC
> > > > > > +#define MT6360_AICR_SHFT     2
> > > > > > +#define MT6360_AICR_400MA    0x6
> > > > > > +/* PMUADCCFG 0x356 */
> > > > > > +#define MT6360_ADCEN_MASK    0x8000
> > > > > > +/* PMUADCRPT1 0x35A */
> > > > > > +#define MT6360_PREFERCH_MASK 0xF0
> > > > > > +#define MT6360_PREFERCH_SHFT 4
> > > > > > +#define MT6360_RPTCH_MASK    0x0F
> > > > > > +
> > > > > > +enum {
> > > > > > +     MT6360_CHAN_USBID = 0,
> > > > > > +     MT6360_CHAN_VBUSDIV5,
> > > > > > +     MT6360_CHAN_VBUSDIV2,
> > > > > > +     MT6360_CHAN_VSYS,
> > > > > > +     MT6360_CHAN_VBAT,
> > > > > > +     MT6360_CHAN_IBUS,
> > > > > > +     MT6360_CHAN_IBAT,
> > > > > > +     MT6360_CHAN_CHG_VDDP,
> > > > > > +     MT6360_CHAN_TEMP_JC,
> > > > > > +     MT6360_CHAN_VREF_TS,
> > > > > > +     MT6360_CHAN_TS,
> > > > > > +     MT6360_CHAN_MAX,
> > > > > > +};
> > > > > > +
> > > > > > +struct mt6360_adc_data {
> > > > > > +     struct device *dev;
> > > > > > +     struct regmap *regmap;
> > > > > > +     struct completion adc_complete;
> > > > > > +     struct mutex adc_lock;
> > > > > > +     ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > > > > > +     int irq;
> > > > > > +};
> > > > > > +
> > > > > > +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> > > > > > +{
> > > > > > +     return ((val * multiplier) + offset) / divisor;
> > > > >
> > > > > Why could we not report these values to userspace or consumer drivers and let
> > > > > them deal with the conversion if they actually needed it?
> > > > > Mapping this to
> > > > >
> > > > > (val + new_offset) * multiplier would be a little messy, but not too bad.
> > > > >
> > > > > The advantage would be that we would then be providing the data needed
> > > > > to get real units for values read from the buffers without having to
> > > > > do all the maths in kernel (without access to floating point).
> > > > >
> > > > >
> > > >
> > > > As above, if I use formula "(val + new_offset) * multiplier",
> > > > the junction temperature channel multiplier will be floating point
> > > > 1.05, i don't know how to express.
> > >
> > > As Andy mentioned, we do this all over the place.
> > > IIO_VAL_INT_PLUS_MICRO
> > >
> > > The key is that we want to push the burden of doing this maths to the user
> > > not the source.
> >
> > ACK.
> > Can I keep IIO_CHAN_INFO_PROCESSED function be reserved for user in
> > kernel space?
> >
>
> No. We have utility functions that will apply the multiplier as needed so
> there is no significant advantage in doing this and it won't be consistent
> with the majority of other drivers.
>

ACK, I will remove IIO_CHAN_INFO_PROCESSED.

> > >
> > > Often what is actually of interest is whether a temperature passed a threshold.
> > > In that case, you can transform the threshold into the units of the ADC (so the
> > > reverse directly to you would do with processed data) and only have to do the
> > > maths once per change of the threshold instead of for every sample.
> > >
> > > There are helper functions to do the maths for you, should you actually
> > > need SI units.
> > >
> >
> > ACK
> >
> > > >
> > > > > > +}
> > > > > > +
> > > > > > +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> > > > > > +{
> > > > > > +     unsigned int regval = 0;
> > > > > > +     const struct converter {
> > > > > > +             int multiplier;
> > > > > > +             int offset;
> > > > > > +             int divisor;
> > > > > > +     } adc_converter[MT6360_CHAN_MAX] = {
> > > > > > +             { 1250, 0, 1}, /* USBID */
> > > > > > +             { 6250, 0, 1}, /* VBUSDIV5 */
> > > > > > +             { 2500, 0, 1}, /* VBUSDIV2 */
> > > > > > +             { 1250, 0, 1}, /* VSYS */
> > > > > > +             { 1250, 0, 1}, /* VBAT */
> > > > > > +             { 2500, 0, 1}, /* IBUS */
> > > > > > +             { 2500, 0, 1}, /* IBAT */
> > > > > > +             { 1250, 0, 1}, /* CHG_VDDP */
> > > > > > +             { 105, -8000, 100}, /* TEMP_JC */
> > > > > > +             { 1250, 0, 1}, /* VREF_TS */
> > > > > > +             { 1250, 0, 1}, /* TS */
> > > > > > +     }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> > > > > > +     int ret;
> > > > > > +
> > > > > > +     sel_converter = adc_converter + chan_idx;
> > > > > > +     if (chan_idx == MT6360_CHAN_IBUS) {
> > > > > > +             /* ibus chan will be affected by aicr config */
> > > > > > +             /* if aicr < 400, apply the special ibus converter */
> > > > > > +             ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > > > > > +             if (ret)
> > > > > > +                     return ret;
> > > > > > +
> > > > > > +             regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > > > > > +             if (regval < MT6360_AICR_400MA)
> > > > > > +                     sel_converter = &sp_ibus_adc_converter;
> > > > > > +     }
> > > > > > +
> > > > > > +     *val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> > > > > > +                                     sel_converter->divisor);
> > > > > > +
> > > > > > +     return 0;
> > > > > > +}
> > > > > > +
> > > > > > +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> > > > > > +{
> > > > > > +     u16 adc_enable;
> > > > > > +     u8 rpt[3];
> > > > > > +     ktime_t start_t, predict_end_t;
> > > > > > +     long timeout;
> > > > > > +     int value, ret;
> > > > > > +
> > > > > > +     mutex_lock(&mad->adc_lock);
> > > > > > +
> > > > > > +     /* select preferred channel that we want */
> > > > > > +     ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > > > > +                              channel << MT6360_PREFERCH_SHFT);
> > > > > > +     if (ret)
> > > > > > +             goto out_adc;
> > > > > > +
> > > > > > +     /* enable adc channel we want and adc_en */
> > > > > > +     adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> > > > > > +     adc_enable = cpu_to_be16(adc_enable);
> > > > >
> > > > > Use a local be16 to store that. It will make it a little clearer
> > > > > that we are doing something 'unusual' here.  Perhaps a comment on
> > > > > why this odd code exists would also help?
> > > > >
> > > >
> > > > ACK
> > > >
> > > > > > +     ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > > > > +     if (ret)
> > > > > > +             goto out_adc;
> > > > > > +
> > > > > > +     start_t = ktime_get();
> > > > > > +     predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> > > > > > +
> > > > > > +     if (ktime_after(start_t, predict_end_t))
> > > > > > +             predict_end_t = ktime_add_ms(start_t, 25);
> > > > > > +     else
> > > > > > +             predict_end_t = ktime_add_ms(start_t, 75);
> > > > > > +
> > > > > > +     enable_irq(mad->irq);
> > > > > > +adc_retry:
> > > > > > +     reinit_completion(&mad->adc_complete);
> > > > > > +
> > > > > > +     /* wait for conversion to complete */
> > > > > > +     timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> > > > > > +     if (timeout == 0) {
> > > > > > +             ret = -ETIMEDOUT;
> > > > > > +             goto out_adc_conv;
> > > > > > +     } else if (timeout < 0) {
> > > > > > +             ret = -EINTR;
> > > > > > +             goto out_adc_conv;
> > > > > > +     }
> > > > > > +
> > > > > > +     ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > > > > > +     if (ret)
> > > > > > +             goto out_adc_conv;
> > > > > > +
> > > > > > +     /* check the current reported channel */
> > > > > > +     if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> > > > > > +             dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);
> > > > >
> > > > > This and the one below feel like error messages rather than debug ones.
> > > > >
> > > >
> > > > We have two function "battery zero current voltage(ZCV)" and "TypeC
> > > > OTP" will auto run ADC at background.
> > > > ZCV_EN will run VBAT_ADC when TA plug in, TypeC OTP will run TS_ADC
> > > > when TypeC attach.
> > > > We need to check report channel for ADC report data match is our desire channel.
> > >
> > > So there is firmware messing with it underneath?  Oh goody.
> > > Add a comment explaining this.
> > >
> >
> > ACK, I try to write a comment as below
> >
> >         /*
> >          * There are two functions, ZCV and TypeC OTP, running ADC
> > VBAT and TS in background,
> >          * and ADC samples are taken on a fixed frequency no matter
> > read the previous one or not.
> >          * To avoid conflict need set minimum time threshold after
> > enable ADC and check report
> >          * channel is the same.
> >          * The worst case is run the same ADC twice and background
> > function is also running,
> >          * ADC conversion sequence is desire channel before start ADC,
> > background ADC, desire
> >          * channel after start ADC. So the minimum correct data is
> > three times of typical
> >          * conversion time.
> >          */
>
> Looks good.
>

ACK

> >
> > > >
> > > > > > +             goto adc_retry;
> > > > > > +     }
> > > > > > +
> > > > > > +     if (!ktime_after(ktime_get(), predict_end_t)) {
> > > > > > +             dev_dbg(mad->dev, "time is not after one adc_conv_t\n");
> > > > >
> > > > > Does this actually happen? If feels like we are being a bit over protective
> > > > > here.  I'd definitely like to see a comment saying why this protection
> > > > > might be needed.
> > > > >
> > > >
> > > > When ADC_EN and MT6360_CHANx_EN is enable, the channel x will keep
> > > > running again and again
> > > > I supposed to get immediate data which is generated after I start it.
> > >
> > > Just to check my understanding.
> > >
> > > This is an edge triggered interrupt and it triggers every time a new sample
> > > is taken.  Those samples are taken on a fixed frequency irrespective of whether
> > > we have read the previous one?
> > >
> >
> > Yes.
> > I use LEVEL_LOW trigger in latest review MFD patch.
>
> I'm not sure I follow that comment.  How can you do that if it's a repeating
> edge trigger?
>

I implement "struct regmap_irq_chip" handle_post_irq ops,
In the end of handle irq, I set the re-trigger bit which will pull irq
high to low again if irq pin is low.

-static int mt6360_pmu_handle_post_irq(void *irq_drv_data)
-{
-       struct mt6360_pmu_info *mpi = irq_drv_data;
-
-       return regmap_update_bits(mpi->regmap,
-               MT6360_PMU_IRQ_SET, MT6360_IRQ_RETRIG, MT6360_IRQ_RETRIG);
-}
-

> >
> > > >
> > > > When I disable ADC_CHANx_EN, the H/W logical ADC is still running.
> > > > If I run the same ADC immediately, I may get the old result about this channel.
> > > > MT6360 ADC typical conversation time is about 25ms.
> > > > So We need ignore which irq trigger below 25ms.
> > >
> > > Normal trick for this sort of case is to just not use the interrupt.
> > > Just read after 25+delta msecs and you are guaranteed to get the right answer.
> > >
> > >
> >
> > ACK, I will try to use polling
> > Is the pseudocode correct?
> >
> > mdelay(predict_end_t);
> > while (true) {
> >     read adc event is occured
> >     check report channel is the same
> >     if the same, read report ADC data and break while loop
> >     else msleep(per ADC conversion time)
> > }
>
> Looks correct to me.  We should 'know' the event has happened but
> still need to check the channel is the expected one.
>

There is a comment in our internal discuss.
If I use msleep as polling interval, the worst case will cause
additional wait time nearly one polling interval.
Can I keep using interrupt for saving time?

> ...
>

Jonathan Cameron Sept. 9, 2020, 9:34 a.m. UTC | #10

On Wed, 9 Sep 2020 07:39:14 +0800
Gene Chen <[e-mail]> wrote:

> Jonathan Cameron <[e-mail]> 於 2020年9月8日 週二 下午9:00寫道：
> >
> > ...
> >  
> > > > > > > +#include <linux/completion.h>
> > > > > > > +#include <linux/interrupt.h>
> > > > > > > +#include <linux/iio/buffer.h>
> > > > > > > +#include <linux/iio/iio.h>
> > > > > > > +#include <linux/iio/trigger_consumer.h>
> > > > > > > +#include <linux/iio/triggered_buffer.h>
> > > > > > > +#include <linux/irq.h>
> > > > > > > +#include <linux/kernel.h>
> > > > > > > +#include <linux/ktime.h>
> > > > > > > +#include <linux/module.h>
> > > > > > > +#include <linux/mutex.h>
> > > > > > > +#include <linux/platform_device.h>
> > > > > > > +#include <linux/regmap.h>
> > > > > > > +
> > > > > > > +#define MT6360_REG_PMUCHGCTRL3       0x313
> > > > > > > +#define MT6360_REG_PMUADCCFG 0x356
> > > > > > > +#define MT6360_REG_PMUADCRPT1        0x35A
> > > > > > > +
> > > > > > > +/* PMUCHGCTRL3 0x313 */
> > > > > > > +#define MT6360_AICR_MASK     0xFC
> > > > > > > +#define MT6360_AICR_SHFT     2
> > > > > > > +#define MT6360_AICR_400MA    0x6
> > > > > > > +/* PMUADCCFG 0x356 */
> > > > > > > +#define MT6360_ADCEN_MASK    0x8000
> > > > > > > +/* PMUADCRPT1 0x35A */
> > > > > > > +#define MT6360_PREFERCH_MASK 0xF0
> > > > > > > +#define MT6360_PREFERCH_SHFT 4
> > > > > > > +#define MT6360_RPTCH_MASK    0x0F
> > > > > > > +
> > > > > > > +enum {
> > > > > > > +     MT6360_CHAN_USBID = 0,
> > > > > > > +     MT6360_CHAN_VBUSDIV5,
> > > > > > > +     MT6360_CHAN_VBUSDIV2,
> > > > > > > +     MT6360_CHAN_VSYS,
> > > > > > > +     MT6360_CHAN_VBAT,
> > > > > > > +     MT6360_CHAN_IBUS,
> > > > > > > +     MT6360_CHAN_IBAT,
> > > > > > > +     MT6360_CHAN_CHG_VDDP,
> > > > > > > +     MT6360_CHAN_TEMP_JC,
> > > > > > > +     MT6360_CHAN_VREF_TS,
> > > > > > > +     MT6360_CHAN_TS,
> > > > > > > +     MT6360_CHAN_MAX,
> > > > > > > +};
> > > > > > > +
> > > > > > > +struct mt6360_adc_data {
> > > > > > > +     struct device *dev;
> > > > > > > +     struct regmap *regmap;
> > > > > > > +     struct completion adc_complete;
> > > > > > > +     struct mutex adc_lock;
> > > > > > > +     ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > > > > > > +     int irq;
> > > > > > > +};
> > > > > > > +
> > > > > > > +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> > > > > > > +{
> > > > > > > +     return ((val * multiplier) + offset) / divisor;  
> > > > > >
> > > > > > Why could we not report these values to userspace or consumer drivers and let
> > > > > > them deal with the conversion if they actually needed it?
> > > > > > Mapping this to
> > > > > >
> > > > > > (val + new_offset) * multiplier would be a little messy, but not too bad.
> > > > > >
> > > > > > The advantage would be that we would then be providing the data needed
> > > > > > to get real units for values read from the buffers without having to
> > > > > > do all the maths in kernel (without access to floating point).
> > > > > >
> > > > > >  
> > > > >
> > > > > As above, if I use formula "(val + new_offset) * multiplier",
> > > > > the junction temperature channel multiplier will be floating point
> > > > > 1.05, i don't know how to express.  
> > > >
> > > > As Andy mentioned, we do this all over the place.
> > > > IIO_VAL_INT_PLUS_MICRO
> > > >
> > > > The key is that we want to push the burden of doing this maths to the user
> > > > not the source.  
> > >
> > > ACK.
> > > Can I keep IIO_CHAN_INFO_PROCESSED function be reserved for user in
> > > kernel space?
> > >  
> >
> > No. We have utility functions that will apply the multiplier as needed so
> > there is no significant advantage in doing this and it won't be consistent
> > with the majority of other drivers.
> >  
> 
> ACK, I will remove IIO_CHAN_INFO_PROCESSED.
> 
> > > >
> > > > Often what is actually of interest is whether a temperature passed a threshold.
> > > > In that case, you can transform the threshold into the units of the ADC (so the
> > > > reverse directly to you would do with processed data) and only have to do the
> > > > maths once per change of the threshold instead of for every sample.
> > > >
> > > > There are helper functions to do the maths for you, should you actually
> > > > need SI units.
> > > >  
> > >
> > > ACK
> > >  
> > > > >  
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> > > > > > > +{
> > > > > > > +     unsigned int regval = 0;
> > > > > > > +     const struct converter {
> > > > > > > +             int multiplier;
> > > > > > > +             int offset;
> > > > > > > +             int divisor;
> > > > > > > +     } adc_converter[MT6360_CHAN_MAX] = {
> > > > > > > +             { 1250, 0, 1}, /* USBID */
> > > > > > > +             { 6250, 0, 1}, /* VBUSDIV5 */
> > > > > > > +             { 2500, 0, 1}, /* VBUSDIV2 */
> > > > > > > +             { 1250, 0, 1}, /* VSYS */
> > > > > > > +             { 1250, 0, 1}, /* VBAT */
> > > > > > > +             { 2500, 0, 1}, /* IBUS */
> > > > > > > +             { 2500, 0, 1}, /* IBAT */
> > > > > > > +             { 1250, 0, 1}, /* CHG_VDDP */
> > > > > > > +             { 105, -8000, 100}, /* TEMP_JC */
> > > > > > > +             { 1250, 0, 1}, /* VREF_TS */
> > > > > > > +             { 1250, 0, 1}, /* TS */
> > > > > > > +     }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> > > > > > > +     int ret;
> > > > > > > +
> > > > > > > +     sel_converter = adc_converter + chan_idx;
> > > > > > > +     if (chan_idx == MT6360_CHAN_IBUS) {
> > > > > > > +             /* ibus chan will be affected by aicr config */
> > > > > > > +             /* if aicr < 400, apply the special ibus converter */
> > > > > > > +             ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > > > > > > +             if (ret)
> > > > > > > +                     return ret;
> > > > > > > +
> > > > > > > +             regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > > > > > > +             if (regval < MT6360_AICR_400MA)
> > > > > > > +                     sel_converter = &sp_ibus_adc_converter;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     *val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> > > > > > > +                                     sel_converter->divisor);
> > > > > > > +
> > > > > > > +     return 0;
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> > > > > > > +{
> > > > > > > +     u16 adc_enable;
> > > > > > > +     u8 rpt[3];
> > > > > > > +     ktime_t start_t, predict_end_t;
> > > > > > > +     long timeout;
> > > > > > > +     int value, ret;
> > > > > > > +
> > > > > > > +     mutex_lock(&mad->adc_lock);
> > > > > > > +
> > > > > > > +     /* select preferred channel that we want */
> > > > > > > +     ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > > > > > +                              channel << MT6360_PREFERCH_SHFT);
> > > > > > > +     if (ret)
> > > > > > > +             goto out_adc;
> > > > > > > +
> > > > > > > +     /* enable adc channel we want and adc_en */
> > > > > > > +     adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> > > > > > > +     adc_enable = cpu_to_be16(adc_enable);  
> > > > > >
> > > > > > Use a local be16 to store that. It will make it a little clearer
> > > > > > that we are doing something 'unusual' here.  Perhaps a comment on
> > > > > > why this odd code exists would also help?
> > > > > >  
> > > > >
> > > > > ACK
> > > > >  
> > > > > > > +     ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > > > > > +     if (ret)
> > > > > > > +             goto out_adc;
> > > > > > > +
> > > > > > > +     start_t = ktime_get();
> > > > > > > +     predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> > > > > > > +
> > > > > > > +     if (ktime_after(start_t, predict_end_t))
> > > > > > > +             predict_end_t = ktime_add_ms(start_t, 25);
> > > > > > > +     else
> > > > > > > +             predict_end_t = ktime_add_ms(start_t, 75);
> > > > > > > +
> > > > > > > +     enable_irq(mad->irq);
> > > > > > > +adc_retry:
> > > > > > > +     reinit_completion(&mad->adc_complete);
> > > > > > > +
> > > > > > > +     /* wait for conversion to complete */
> > > > > > > +     timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> > > > > > > +     if (timeout == 0) {
> > > > > > > +             ret = -ETIMEDOUT;
> > > > > > > +             goto out_adc_conv;
> > > > > > > +     } else if (timeout < 0) {
> > > > > > > +             ret = -EINTR;
> > > > > > > +             goto out_adc_conv;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > > > > > > +     if (ret)
> > > > > > > +             goto out_adc_conv;
> > > > > > > +
> > > > > > > +     /* check the current reported channel */
> > > > > > > +     if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> > > > > > > +             dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);  
> > > > > >
> > > > > > This and the one below feel like error messages rather than debug ones.
> > > > > >  
> > > > >
> > > > > We have two function "battery zero current voltage(ZCV)" and "TypeC
> > > > > OTP" will auto run ADC at background.
> > > > > ZCV_EN will run VBAT_ADC when TA plug in, TypeC OTP will run TS_ADC
> > > > > when TypeC attach.
> > > > > We need to check report channel for ADC report data match is our desire channel.  
> > > >
> > > > So there is firmware messing with it underneath?  Oh goody.
> > > > Add a comment explaining this.
> > > >  
> > >
> > > ACK, I try to write a comment as below
> > >
> > >         /*
> > >          * There are two functions, ZCV and TypeC OTP, running ADC
> > > VBAT and TS in background,
> > >          * and ADC samples are taken on a fixed frequency no matter
> > > read the previous one or not.
> > >          * To avoid conflict need set minimum time threshold after
> > > enable ADC and check report
> > >          * channel is the same.
> > >          * The worst case is run the same ADC twice and background
> > > function is also running,
> > >          * ADC conversion sequence is desire channel before start ADC,
> > > background ADC, desire
> > >          * channel after start ADC. So the minimum correct data is
> > > three times of typical
> > >          * conversion time.
> > >          */  
> >
> > Looks good.
> >  
> 
> ACK
> 
> > >  
> > > > >  
> > > > > > > +             goto adc_retry;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     if (!ktime_after(ktime_get(), predict_end_t)) {
> > > > > > > +             dev_dbg(mad->dev, "time is not after one adc_conv_t\n");  
> > > > > >
> > > > > > Does this actually happen? If feels like we are being a bit over protective
> > > > > > here.  I'd definitely like to see a comment saying why this protection
> > > > > > might be needed.
> > > > > >  
> > > > >
> > > > > When ADC_EN and MT6360_CHANx_EN is enable, the channel x will keep
> > > > > running again and again
> > > > > I supposed to get immediate data which is generated after I start it.  
> > > >
> > > > Just to check my understanding.
> > > >
> > > > This is an edge triggered interrupt and it triggers every time a new sample
> > > > is taken.  Those samples are taken on a fixed frequency irrespective of whether
> > > > we have read the previous one?
> > > >  
> > >
> > > Yes.
> > > I use LEVEL_LOW trigger in latest review MFD patch.  
> >
> > I'm not sure I follow that comment.  How can you do that if it's a repeating
> > edge trigger?
> >  
> 
> I implement "struct regmap_irq_chip" handle_post_irq ops,
> In the end of handle irq, I set the re-trigger bit which will pull irq
> high to low again if irq pin is low.
> 
> -static int mt6360_pmu_handle_post_irq(void *irq_drv_data)
> -{
> -       struct mt6360_pmu_info *mpi = irq_drv_data;
> -
> -       return regmap_update_bits(mpi->regmap,
> -               MT6360_PMU_IRQ_SET, MT6360_IRQ_RETRIG, MT6360_IRQ_RETRIG);
> -}
> -

Ah understood I think.

> 
> > >  
> > > > >
> > > > > When I disable ADC_CHANx_EN, the H/W logical ADC is still running.
> > > > > If I run the same ADC immediately, I may get the old result about this channel.
> > > > > MT6360 ADC typical conversation time is about 25ms.
> > > > > So We need ignore which irq trigger below 25ms.  
> > > >
> > > > Normal trick for this sort of case is to just not use the interrupt.
> > > > Just read after 25+delta msecs and you are guaranteed to get the right answer.
> > > >
> > > >  
> > >
> > > ACK, I will try to use polling
> > > Is the pseudocode correct?
> > >
> > > mdelay(predict_end_t);
> > > while (true) {
> > >     read adc event is occured
> > >     check report channel is the same
> > >     if the same, read report ADC data and break while loop
> > >     else msleep(per ADC conversion time)
> > > }  
> >
> > Looks correct to me.  We should 'know' the event has happened but
> > still need to check the channel is the expected one.
> >  
> 
> There is a comment in our internal discuss.
> If I use msleep as polling interval, the worst case will cause
> additional wait time nearly one polling interval.
> Can I keep using interrupt for saving time?

You could but it is complicating the code to deal with frankly stupid
hardware design which I'm not that keen on.

If it ends up clean enough with a lot comments on why the odd parts
are there, then maybe it will be fine.

Jonathan

> 
> > ...
> >

Gene Chen Sept. 10, 2020, 12:14 a.m. UTC | #11

Gene Chen <[e-mail]> 於 2020年9月9日 週三 上午7:39寫道：
>
> Jonathan Cameron <[e-mail]> 於 2020年9月8日 週二 下午9:00寫道：
> >
> > ...
> >
> > > > > > > +#include <linux/completion.h>
> > > > > > > +#include <linux/interrupt.h>
> > > > > > > +#include <linux/iio/buffer.h>
> > > > > > > +#include <linux/iio/iio.h>
> > > > > > > +#include <linux/iio/trigger_consumer.h>
> > > > > > > +#include <linux/iio/triggered_buffer.h>
> > > > > > > +#include <linux/irq.h>
> > > > > > > +#include <linux/kernel.h>
> > > > > > > +#include <linux/ktime.h>
> > > > > > > +#include <linux/module.h>
> > > > > > > +#include <linux/mutex.h>
> > > > > > > +#include <linux/platform_device.h>
> > > > > > > +#include <linux/regmap.h>
> > > > > > > +
> > > > > > > +#define MT6360_REG_PMUCHGCTRL3       0x313
> > > > > > > +#define MT6360_REG_PMUADCCFG 0x356
> > > > > > > +#define MT6360_REG_PMUADCRPT1        0x35A
> > > > > > > +
> > > > > > > +/* PMUCHGCTRL3 0x313 */
> > > > > > > +#define MT6360_AICR_MASK     0xFC
> > > > > > > +#define MT6360_AICR_SHFT     2
> > > > > > > +#define MT6360_AICR_400MA    0x6
> > > > > > > +/* PMUADCCFG 0x356 */
> > > > > > > +#define MT6360_ADCEN_MASK    0x8000
> > > > > > > +/* PMUADCRPT1 0x35A */
> > > > > > > +#define MT6360_PREFERCH_MASK 0xF0
> > > > > > > +#define MT6360_PREFERCH_SHFT 4
> > > > > > > +#define MT6360_RPTCH_MASK    0x0F
> > > > > > > +
> > > > > > > +enum {
> > > > > > > +     MT6360_CHAN_USBID = 0,
> > > > > > > +     MT6360_CHAN_VBUSDIV5,
> > > > > > > +     MT6360_CHAN_VBUSDIV2,
> > > > > > > +     MT6360_CHAN_VSYS,
> > > > > > > +     MT6360_CHAN_VBAT,
> > > > > > > +     MT6360_CHAN_IBUS,
> > > > > > > +     MT6360_CHAN_IBAT,
> > > > > > > +     MT6360_CHAN_CHG_VDDP,
> > > > > > > +     MT6360_CHAN_TEMP_JC,
> > > > > > > +     MT6360_CHAN_VREF_TS,
> > > > > > > +     MT6360_CHAN_TS,
> > > > > > > +     MT6360_CHAN_MAX,
> > > > > > > +};
> > > > > > > +
> > > > > > > +struct mt6360_adc_data {
> > > > > > > +     struct device *dev;
> > > > > > > +     struct regmap *regmap;
> > > > > > > +     struct completion adc_complete;
> > > > > > > +     struct mutex adc_lock;
> > > > > > > +     ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > > > > > > +     int irq;
> > > > > > > +};
> > > > > > > +
> > > > > > > +static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
> > > > > > > +{
> > > > > > > +     return ((val * multiplier) + offset) / divisor;
> > > > > >
> > > > > > Why could we not report these values to userspace or consumer drivers and let
> > > > > > them deal with the conversion if they actually needed it?
> > > > > > Mapping this to
> > > > > >
> > > > > > (val + new_offset) * multiplier would be a little messy, but not too bad.
> > > > > >
> > > > > > The advantage would be that we would then be providing the data needed
> > > > > > to get real units for values read from the buffers without having to
> > > > > > do all the maths in kernel (without access to floating point).
> > > > > >
> > > > > >
> > > > >
> > > > > As above, if I use formula "(val + new_offset) * multiplier",
> > > > > the junction temperature channel multiplier will be floating point
> > > > > 1.05, i don't know how to express.
> > > >
> > > > As Andy mentioned, we do this all over the place.
> > > > IIO_VAL_INT_PLUS_MICRO
> > > >
> > > > The key is that we want to push the burden of doing this maths to the user
> > > > not the source.
> > >
> > > ACK.
> > > Can I keep IIO_CHAN_INFO_PROCESSED function be reserved for user in
> > > kernel space?
> > >
> >
> > No. We have utility functions that will apply the multiplier as needed so
> > there is no significant advantage in doing this and it won't be consistent
> > with the majority of other drivers.
> >
>
> ACK, I will remove IIO_CHAN_INFO_PROCESSED.
>
> > > >
> > > > Often what is actually of interest is whether a temperature passed a threshold.
> > > > In that case, you can transform the threshold into the units of the ADC (so the
> > > > reverse directly to you would do with processed data) and only have to do the
> > > > maths once per change of the threshold instead of for every sample.
> > > >
> > > > There are helper functions to do the maths for you, should you actually
> > > > need SI units.
> > > >
> > >
> > > ACK
> > >
> > > > >
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
> > > > > > > +{
> > > > > > > +     unsigned int regval = 0;
> > > > > > > +     const struct converter {
> > > > > > > +             int multiplier;
> > > > > > > +             int offset;
> > > > > > > +             int divisor;
> > > > > > > +     } adc_converter[MT6360_CHAN_MAX] = {
> > > > > > > +             { 1250, 0, 1}, /* USBID */
> > > > > > > +             { 6250, 0, 1}, /* VBUSDIV5 */
> > > > > > > +             { 2500, 0, 1}, /* VBUSDIV2 */
> > > > > > > +             { 1250, 0, 1}, /* VSYS */
> > > > > > > +             { 1250, 0, 1}, /* VBAT */
> > > > > > > +             { 2500, 0, 1}, /* IBUS */
> > > > > > > +             { 2500, 0, 1}, /* IBAT */
> > > > > > > +             { 1250, 0, 1}, /* CHG_VDDP */
> > > > > > > +             { 105, -8000, 100}, /* TEMP_JC */
> > > > > > > +             { 1250, 0, 1}, /* VREF_TS */
> > > > > > > +             { 1250, 0, 1}, /* TS */
> > > > > > > +     }, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
> > > > > > > +     int ret;
> > > > > > > +
> > > > > > > +     sel_converter = adc_converter + chan_idx;
> > > > > > > +     if (chan_idx == MT6360_CHAN_IBUS) {
> > > > > > > +             /* ibus chan will be affected by aicr config */
> > > > > > > +             /* if aicr < 400, apply the special ibus converter */
> > > > > > > +             ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > > > > > > +             if (ret)
> > > > > > > +                     return ret;
> > > > > > > +
> > > > > > > +             regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > > > > > > +             if (regval < MT6360_AICR_400MA)
> > > > > > > +                     sel_converter = &sp_ibus_adc_converter;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     *val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
> > > > > > > +                                     sel_converter->divisor);
> > > > > > > +
> > > > > > > +     return 0;
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
> > > > > > > +{
> > > > > > > +     u16 adc_enable;
> > > > > > > +     u8 rpt[3];
> > > > > > > +     ktime_t start_t, predict_end_t;
> > > > > > > +     long timeout;
> > > > > > > +     int value, ret;
> > > > > > > +
> > > > > > > +     mutex_lock(&mad->adc_lock);
> > > > > > > +
> > > > > > > +     /* select preferred channel that we want */
> > > > > > > +     ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > > > > > > +                              channel << MT6360_PREFERCH_SHFT);
> > > > > > > +     if (ret)
> > > > > > > +             goto out_adc;
> > > > > > > +
> > > > > > > +     /* enable adc channel we want and adc_en */
> > > > > > > +     adc_enable = MT6360_ADCEN_MASK | BIT(channel);
> > > > > > > +     adc_enable = cpu_to_be16(adc_enable);
> > > > > >
> > > > > > Use a local be16 to store that. It will make it a little clearer
> > > > > > that we are doing something 'unusual' here.  Perhaps a comment on
> > > > > > why this odd code exists would also help?
> > > > > >
> > > > >
> > > > > ACK
> > > > >
> > > > > > > +     ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
> > > > > > > +     if (ret)
> > > > > > > +             goto out_adc;
> > > > > > > +
> > > > > > > +     start_t = ktime_get();
> > > > > > > +     predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
> > > > > > > +
> > > > > > > +     if (ktime_after(start_t, predict_end_t))
> > > > > > > +             predict_end_t = ktime_add_ms(start_t, 25);
> > > > > > > +     else
> > > > > > > +             predict_end_t = ktime_add_ms(start_t, 75);
> > > > > > > +
> > > > > > > +     enable_irq(mad->irq);
> > > > > > > +adc_retry:
> > > > > > > +     reinit_completion(&mad->adc_complete);
> > > > > > > +
> > > > > > > +     /* wait for conversion to complete */
> > > > > > > +     timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
> > > > > > > +     if (timeout == 0) {
> > > > > > > +             ret = -ETIMEDOUT;
> > > > > > > +             goto out_adc_conv;
> > > > > > > +     } else if (timeout < 0) {
> > > > > > > +             ret = -EINTR;
> > > > > > > +             goto out_adc_conv;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > > > > > > +     if (ret)
> > > > > > > +             goto out_adc_conv;
> > > > > > > +
> > > > > > > +     /* check the current reported channel */
> > > > > > > +     if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
> > > > > > > +             dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);
> > > > > >
> > > > > > This and the one below feel like error messages rather than debug ones.
> > > > > >
> > > > >
> > > > > We have two function "battery zero current voltage(ZCV)" and "TypeC
> > > > > OTP" will auto run ADC at background.
> > > > > ZCV_EN will run VBAT_ADC when TA plug in, TypeC OTP will run TS_ADC
> > > > > when TypeC attach.
> > > > > We need to check report channel for ADC report data match is our desire channel.
> > > >
> > > > So there is firmware messing with it underneath?  Oh goody.
> > > > Add a comment explaining this.
> > > >
> > >
> > > ACK, I try to write a comment as below
> > >
> > >         /*
> > >          * There are two functions, ZCV and TypeC OTP, running ADC
> > > VBAT and TS in background,
> > >          * and ADC samples are taken on a fixed frequency no matter
> > > read the previous one or not.
> > >          * To avoid conflict need set minimum time threshold after
> > > enable ADC and check report
> > >          * channel is the same.
> > >          * The worst case is run the same ADC twice and background
> > > function is also running,
> > >          * ADC conversion sequence is desire channel before start ADC,
> > > background ADC, desire
> > >          * channel after start ADC. So the minimum correct data is
> > > three times of typical
> > >          * conversion time.
> > >          */
> >
> > Looks good.
> >
>
> ACK
>
> > >
> > > > >
> > > > > > > +             goto adc_retry;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     if (!ktime_after(ktime_get(), predict_end_t)) {
> > > > > > > +             dev_dbg(mad->dev, "time is not after one adc_conv_t\n");
> > > > > >
> > > > > > Does this actually happen? If feels like we are being a bit over protective
> > > > > > here.  I'd definitely like to see a comment saying why this protection
> > > > > > might be needed.
> > > > > >
> > > > >
> > > > > When ADC_EN and MT6360_CHANx_EN is enable, the channel x will keep
> > > > > running again and again
> > > > > I supposed to get immediate data which is generated after I start it.
> > > >
> > > > Just to check my understanding.
> > > >
> > > > This is an edge triggered interrupt and it triggers every time a new sample
> > > > is taken.  Those samples are taken on a fixed frequency irrespective of whether
> > > > we have read the previous one?
> > > >
> > >
> > > Yes.
> > > I use LEVEL_LOW trigger in latest review MFD patch.
> >
> > I'm not sure I follow that comment.  How can you do that if it's a repeating
> > edge trigger?
> >
>
> I implement "struct regmap_irq_chip" handle_post_irq ops,
> In the end of handle irq, I set the re-trigger bit which will pull irq
> high to low again if irq pin is low.
>
> -static int mt6360_pmu_handle_post_irq(void *irq_drv_data)
> -{
> -       struct mt6360_pmu_info *mpi = irq_drv_data;
> -
> -       return regmap_update_bits(mpi->regmap,
> -               MT6360_PMU_IRQ_SET, MT6360_IRQ_RETRIG, MT6360_IRQ_RETRIG);
> -}
> -
>
> > >
> > > > >
> > > > > When I disable ADC_CHANx_EN, the H/W logical ADC is still running.
> > > > > If I run the same ADC immediately, I may get the old result about this channel.
> > > > > MT6360 ADC typical conversation time is about 25ms.
> > > > > So We need ignore which irq trigger below 25ms.
> > > >
> > > > Normal trick for this sort of case is to just not use the interrupt.
> > > > Just read after 25+delta msecs and you are guaranteed to get the right answer.
> > > >
> > > >
> > >
> > > ACK, I will try to use polling
> > > Is the pseudocode correct?
> > >
> > > mdelay(predict_end_t);
> > > while (true) {
> > >     read adc event is occured
> > >     check report channel is the same
> > >     if the same, read report ADC data and break while loop
> > >     else msleep(per ADC conversion time)
> > > }
> >
> > Looks correct to me.  We should 'know' the event has happened but
> > still need to check the channel is the expected one.
> >
>
> There is a comment in our internal discuss.
> If I use msleep as polling interval, the worst case will cause
> additional wait time nearly one polling interval.
> Can I keep using interrupt for saving time?
>

ACK, I will use polling only.
This is our IC limitation which will be fixed in next generation.

> > ...
> >

Patch

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 66d9cc0..07dcea7 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -703,6 +703,17 @@  config MCP3911
 	  This driver can also be built as a module. If so, the module will be
 	  called mcp3911.
 
+config MEDIATEK_MT6360_ADC
+	tristate "Mediatek MT6360 ADC Part"
+	depends on MFD_MT6360
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say Y here to enable MT6360 ADC Part.
+	  Integrated for System Monitoring include
+	  Charger and Battery Current, Voltage and
+	  Temperature
+
 config MEDIATEK_MT6577_AUXADC
 	tristate "MediaTek AUXADC driver"
 	depends on ARCH_MEDIATEK || COMPILE_TEST
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 90f94ad..5fca90a 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -65,6 +65,7 @@  obj-$(CONFIG_MAX9611) += max9611.o
 obj-$(CONFIG_MCP320X) += mcp320x.o
 obj-$(CONFIG_MCP3422) += mcp3422.o
 obj-$(CONFIG_MCP3911) += mcp3911.o
+obj-$(CONFIG_MEDIATEK_MT6360_ADC) += mt6360-adc.o
 obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o
 obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
 obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c
new file mode 100644
index 0000000..5eed812
--- /dev/null
+++ b/drivers/iio/adc/mt6360-adc.c
@@ -0,0 +1,366 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020 MediaTek Inc.
+ *
+ * Author: Gene Chen <[e-mail]>
+ */
+
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define MT6360_REG_PMUCHGCTRL3	0x313
+#define MT6360_REG_PMUADCCFG	0x356
+#define MT6360_REG_PMUADCRPT1	0x35A
+
+/* PMUCHGCTRL3 0x313 */
+#define MT6360_AICR_MASK	0xFC
+#define MT6360_AICR_SHFT	2
+#define MT6360_AICR_400MA	0x6
+/* PMUADCCFG 0x356 */
+#define MT6360_ADCEN_MASK	0x8000
+/* PMUADCRPT1 0x35A */
+#define MT6360_PREFERCH_MASK	0xF0
+#define MT6360_PREFERCH_SHFT	4
+#define MT6360_RPTCH_MASK	0x0F
+
+enum {
+	MT6360_CHAN_USBID = 0,
+	MT6360_CHAN_VBUSDIV5,
+	MT6360_CHAN_VBUSDIV2,
+	MT6360_CHAN_VSYS,
+	MT6360_CHAN_VBAT,
+	MT6360_CHAN_IBUS,
+	MT6360_CHAN_IBAT,
+	MT6360_CHAN_CHG_VDDP,
+	MT6360_CHAN_TEMP_JC,
+	MT6360_CHAN_VREF_TS,
+	MT6360_CHAN_TS,
+	MT6360_CHAN_MAX,
+};
+
+struct mt6360_adc_data {
+	struct device *dev;
+	struct regmap *regmap;
+	struct completion adc_complete;
+	struct mutex adc_lock;
+	ktime_t last_off_timestamps[MT6360_CHAN_MAX];
+	int irq;
+};
+
+static inline int mt6360_adc_val_converter(int val, int multiplier, int offset, int divisor)
+{
+	return ((val * multiplier) + offset) / divisor;
+}
+
+static int mt6360_adc_convert_processed_val(struct mt6360_adc_data *info, int chan_idx, int *val)
+{
+	unsigned int regval = 0;
+	const struct converter {
+		int multiplier;
+		int offset;
+		int divisor;
+	} adc_converter[MT6360_CHAN_MAX] = {
+		{ 1250, 0, 1}, /* USBID */
+		{ 6250, 0, 1}, /* VBUSDIV5 */
+		{ 2500, 0, 1}, /* VBUSDIV2 */
+		{ 1250, 0, 1}, /* VSYS */
+		{ 1250, 0, 1}, /* VBAT */
+		{ 2500, 0, 1}, /* IBUS */
+		{ 2500, 0, 1}, /* IBAT */
+		{ 1250, 0, 1}, /* CHG_VDDP */
+		{ 105, -8000, 100}, /* TEMP_JC */
+		{ 1250, 0, 1}, /* VREF_TS */
+		{ 1250, 0, 1}, /* TS */
+	}, sp_ibus_adc_converter = { 1900, 0, 1 }, *sel_converter;
+	int ret;
+
+	sel_converter = adc_converter + chan_idx;
+	if (chan_idx == MT6360_CHAN_IBUS) {
+		/* ibus chan will be affected by aicr config */
+		/* if aicr < 400, apply the special ibus converter */
+		ret = regmap_read(info->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
+		if (ret)
+			return ret;
+
+		regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
+		if (regval < MT6360_AICR_400MA)
+			sel_converter = &sp_ibus_adc_converter;
+	}
+
+	*val = mt6360_adc_val_converter(*val, sel_converter->multiplier, sel_converter->offset,
+					sel_converter->divisor);
+
+	return 0;
+}
+
+static int mt6360_adc_read_processed(struct mt6360_adc_data *mad, int channel, int *val)
+{
+	u16 adc_enable;
+	u8 rpt[3];
+	ktime_t start_t, predict_end_t;
+	long timeout;
+	int value, ret;
+
+	mutex_lock(&mad->adc_lock);
+
+	/* select preferred channel that we want */
+	ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
+				 channel << MT6360_PREFERCH_SHFT);
+	if (ret)
+		goto out_adc;
+
+	/* enable adc channel we want and adc_en */
+	adc_enable = MT6360_ADCEN_MASK | BIT(channel);
+	adc_enable = cpu_to_be16(adc_enable);
+	ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
+	if (ret)
+		goto out_adc;
+
+	start_t = ktime_get();
+	predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 50);
+
+	if (ktime_after(start_t, predict_end_t))
+		predict_end_t = ktime_add_ms(start_t, 25);
+	else
+		predict_end_t = ktime_add_ms(start_t, 75);
+
+	enable_irq(mad->irq);
+adc_retry:
+	reinit_completion(&mad->adc_complete);
+
+	/* wait for conversion to complete */
+	timeout = wait_for_completion_timeout(&mad->adc_complete, msecs_to_jiffies(200));
+	if (timeout == 0) {
+		ret = -ETIMEDOUT;
+		goto out_adc_conv;
+	} else if (timeout < 0) {
+		ret = -EINTR;
+		goto out_adc_conv;
+	}
+
+	ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
+	if (ret)
+		goto out_adc_conv;
+
+	/* check the current reported channel */
+	if ((rpt[0] & MT6360_RPTCH_MASK) != channel) {
+		dev_dbg(mad->dev, "not wanted channel report [%02x]\n", rpt[0]);
+		goto adc_retry;
+	}
+
+	if (!ktime_after(ktime_get(), predict_end_t)) {
+		dev_dbg(mad->dev, "time is not after one adc_conv_t\n");
+		goto adc_retry;
+	}
+
+	value = (rpt[1] << 8) | rpt[2];
+
+	ret = mt6360_adc_convert_processed_val(mad, channel, &value);
+	if (ret)
+		goto out_adc_conv;
+
+	*val = value;
+	ret = IIO_VAL_INT;
+
+out_adc_conv:
+	disable_irq(mad->irq);
+	adc_enable = MT6360_ADCEN_MASK;
+	adc_enable = cpu_to_be16(adc_enable);
+	regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(u16));
+	mad->last_off_timestamps[channel] = ktime_get();
+	/* set prefer channel to 0xf */
+	regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
+			   0xF << MT6360_PREFERCH_SHFT);
+out_adc:
+	mutex_unlock(&mad->adc_lock);
+
+	return ret;
+}
+
+static int mt6360_adc_read_raw(struct iio_dev *iio_dev, const struct iio_chan_spec *chan,
+			       int *val, int *val2, long mask)
+{
+	struct mt6360_adc_data *mad = iio_priv(iio_dev);
+
+	if (mask == IIO_CHAN_INFO_PROCESSED)
+		return mt6360_adc_read_processed(mad, chan->channel, val);
+
+	return -EINVAL;
+}
+
+static const struct iio_info mt6360_adc_iio_info = {
+	.read_raw = mt6360_adc_read_raw,
+};
+
+#define MT6360_ADC_CHAN(_idx, _type) {				\
+	.type = _type,						\
+	.channel = MT6360_CHAN_##_idx,				\
+	.scan_index = MT6360_CHAN_##_idx,			\
+	.extend_name = #_idx,					\
+	.datasheet_name = #_idx,				\
+	.scan_type =  {						\
+		.sign = 's',					\
+		.realbits = 32,					\
+		.storagebits = 32,				\
+		.endianness = IIO_CPU,				\
+	},							\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),	\
+	.indexed = 1,						\
+}
+
+static const struct iio_chan_spec mt6360_adc_channels[] = {
+	MT6360_ADC_CHAN(USBID, IIO_VOLTAGE),
+	MT6360_ADC_CHAN(VBUSDIV5, IIO_VOLTAGE),
+	MT6360_ADC_CHAN(VBUSDIV2, IIO_VOLTAGE),
+	MT6360_ADC_CHAN(VSYS, IIO_VOLTAGE),
+	MT6360_ADC_CHAN(VBAT, IIO_VOLTAGE),
+	MT6360_ADC_CHAN(IBUS, IIO_CURRENT),
+	MT6360_ADC_CHAN(IBAT, IIO_CURRENT),
+	MT6360_ADC_CHAN(CHG_VDDP, IIO_VOLTAGE),
+	MT6360_ADC_CHAN(TEMP_JC, IIO_TEMP),
+	MT6360_ADC_CHAN(VREF_TS, IIO_VOLTAGE),
+	MT6360_ADC_CHAN(TS, IIO_VOLTAGE),
+	IIO_CHAN_SOFT_TIMESTAMP(MT6360_CHAN_MAX),
+};
+
+static irqreturn_t mt6360_pmu_adc_donei_handler(int irq, void *data)
+{
+	struct mt6360_adc_data *mad = iio_priv(data);
+
+	complete(&mad->adc_complete);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mt6360_adc_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	/* 11 ch s32 numbers + 1 s64 timestamp */
+	s32 data[MT6360_CHAN_MAX + 2] __aligned(8);
+	int i = 0, bit, val, ret;
+
+	for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) {
+		const struct iio_chan_spec *chan = indio_dev->channels + bit;
+
+		ret = mt6360_adc_read_raw(indio_dev, chan, &val, NULL, IIO_CHAN_INFO_PROCESSED);
+		if (ret != IIO_VAL_INT) {
+			dev_warn(&indio_dev->dev, "Failed to get %d conversion val\n", bit);
+			goto out;
+		}
+
+		data[i++] = val;
+	}
+	iio_push_to_buffers_with_timestamp(indio_dev, data, iio_get_time_ns(indio_dev));
+out:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static inline int mt6360_adc_reset(struct mt6360_adc_data *info)
+{
+	u8 configs[3] = {0x80, 0, 0};
+	ktime_t all_off_time;
+	int i;
+
+	all_off_time = ktime_get();
+	for (i = 0; i < MT6360_CHAN_MAX; i++)
+		info->last_off_timestamps[i] = all_off_time;
+
+	/* enable adc_en, clear adc_chn_en/zcv_en/adc_wait_t/adc_idle_t */
+	return regmap_raw_write(info->regmap, MT6360_REG_PMUADCCFG, configs, sizeof(configs));
+}
+
+static int mt6360_adc_probe(struct platform_device *pdev)
+{
+	struct mt6360_adc_data *mad;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*mad));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	mad = iio_priv(indio_dev);
+	mad->dev = &pdev->dev;
+	init_completion(&mad->adc_complete);
+	mutex_init(&mad->adc_lock);
+
+	mad->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!mad->regmap) {
+		dev_err(&pdev->dev, "Failed to get parent regmap\n");
+		return -ENODEV;
+	}
+
+	ret = mt6360_adc_reset(mad);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to reset adc\n");
+		return ret;
+	}
+
+	mad->irq = platform_get_irq_byname(pdev, "adc_donei");
+	if (mad->irq < 0) {
+		dev_err(&pdev->dev, "Failed to get adc_done irq\n");
+		return mad->irq;
+	}
+
+	irq_set_status_flags(mad->irq, IRQ_NOAUTOEN);
+	ret = devm_request_threaded_irq(&pdev->dev, mad->irq, NULL, mt6360_pmu_adc_donei_handler, 0,
+					"adc_donei", indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register adc_done irq\n");
+		return ret;
+	}
+
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &mt6360_adc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = mt6360_adc_channels;
+	indio_dev->num_channels = ARRAY_SIZE(mt6360_adc_channels);
+
+	ret = devm_iio_triggered_buffer_setup(&pdev->dev, indio_dev, NULL,
+					      mt6360_adc_trigger_handler, NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to allocate iio trigger buffer\n");
+		return ret;
+	}
+
+	ret = devm_iio_device_register(&pdev->dev, indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register iio device\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id __maybe_unused mt6360_adc_of_id[] = {
+	{ .compatible = "mediatek,mt6360-adc", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mt6360_adc_of_id);
+
+static struct platform_driver mt6360_adc_driver = {
+	.driver = {
+		.name = "mt6360-adc",
+		.of_match_table = mt6360_adc_of_id,
+	},
+	.probe = mt6360_adc_probe,
+};
+module_platform_driver(mt6360_adc_driver);
+
+MODULE_AUTHOR("Gene Chen <[e-mail]>");
+MODULE_DESCRIPTION("MT6360 ADC Driver");
+MODULE_LICENSE("GPL v2");