diff mbox series

[v3,2/2] iio: adc: Add driver for ADS7128 / ADS7138

Message ID 20250206-adc_ml-v3-2-1d0bd3483aa2@softing.com (mailing list archive)
State Changes Requested
Headers show
Series Support for TI ADS7128 and ADS7138 ADCs | expand

Commit Message

Tobias Sperling via B4 Relay Feb. 6, 2025, 3:41 p.m. UTC
From: Tobias Sperling <tobias.sperling@softing.com>

Add driver for ADS7128 and ADS7138 12-bit, 8-channel analog-to-digital
converters. These ADCs have a wide operating range and a wide feature
set. Communication is based on the I2C interface.
ADS7128 differs in the addition of further hardware features, like a
root-mean-square (RMS) and a zero-crossing-detect (ZCD) module.

Signed-off-by: Tobias Sperling <tobias.sperling@softing.com>
---
 drivers/iio/adc/Kconfig      |  10 +
 drivers/iio/adc/Makefile     |   1 +
 drivers/iio/adc/ti-ads7138.c | 746 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 757 insertions(+)

Comments

Jonathan Cameron Feb. 8, 2025, 3:05 p.m. UTC | #1
On Thu, 06 Feb 2025 16:41:49 +0100
Tobias Sperling via B4 Relay <devnull+tobias.sperling.softing.com@kernel.org> wrote:

> From: Tobias Sperling <tobias.sperling@softing.com>
> 
> Add driver for ADS7128 and ADS7138 12-bit, 8-channel analog-to-digital
> converters. These ADCs have a wide operating range and a wide feature
> set. Communication is based on the I2C interface.
> ADS7128 differs in the addition of further hardware features, like a
> root-mean-square (RMS) and a zero-crossing-detect (ZCD) module.
> 
> Signed-off-by: Tobias Sperling <tobias.sperling@softing.com>

Hi Tobias,

Minor comments below and one question about power management

Thanks,

Jonathan


> diff --git a/drivers/iio/adc/ti-ads7138.c b/drivers/iio/adc/ti-ads7138.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..16d9ae7426522ddad62fd78ac6138aab6ab41101
> --- /dev/null
> +++ b/drivers/iio/adc/ti-ads7138.c
> @@ -0,0 +1,746 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * ADS7138 - Texas Instruments Analog-to-Digital Converter
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/cleanup.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/unaligned.h>
> +
> +#include <linux/iio/events.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/types.h>
> +
> +/* AVDD (VREF) operating range in millivolts */

Generally a bad idea to use wild cards.  They go wrong far too often
as manufacturers love to make other uses of the product codes they cover.
Just pick a device that these values apply to and use that name
throughout.  Given driver name I'd just call these all ADS7138
unless they don't apply to that chip.
We've been bitten by this wild card thing too often in the past!

> +#define ADS71x8_AVDD_MV_MIN		2350


Good perhaps to have a comment on what the two sides of this are
and why it is structure like this.

> +static const int ads71x8_samp_freqs_bits[2][26] = {
> +	{
> +		163, 244, 326, 488, 651, 977, 1302, 1953,
> +		2604, 3906, 5208, 7813, 10417, 15625, 20833, 31250,
> +		41667, 62500, 83333, 125000, 166667, 250000, 333333, 500000,
> +		666667, 1000000
> +	}, {
> +		0x1f, 0x1e, 0x1d, 0x1c, 0x1b, 0x1a, 0x19, 0x18,
> +		0x17, 0x16, 0x15, 0x14, 0x13, 0x12, 0x11, 0x10,
> +		/* Here is a hole, due to duplicate frequencies */
> +		0x09, 0x08, 0x07, 0x06, 0x05, 0x04, 0x03, 0x02,
> +		0x01, 0x00
> +	}
> +};


> +static int ads71x8_i2c_write(const struct i2c_client *client, u8 reg, u8 value)
> +{
> +	return ads71x8_i2c_write_block(client, reg, &value, sizeof(value));

Maybe this should use the single register write (figure 35) rather than bulk one?
It makes no real difference though other than different opcode.

> +}
> +
> +static int ads71x8_i2c_setclear_bit(const struct i2c_client *client, u8 reg,
> +				    u8 bits, u8 opcode)

> +{
> +	u8 buf[3] = { opcode, reg, bits };
> +	int ret;
> +
> +	ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
> +	if (ret < 0)
> +		return ret;
> +	if (ret != ARRAY_SIZE(buf))
> +		return -EIO;
> +
> +	return 0;
> +}

Whilst this is currently just used for setclear_bit, it is slightly more general
so maybe the name should reflect that it could be used for single register
writes for instance.  Naming is hard though and I can't immediately think
what name covers this combination.  

> +
> +static int ads71x8_read_event(struct iio_dev *indio_dev,
> +			      const struct iio_chan_spec *chan,
> +			      enum iio_event_type type,
> +			      enum iio_event_direction dir,
> +			      enum iio_event_info info, int *val, int *val2)
> +{
> +	struct ads71x8_data *data = iio_priv(indio_dev);
> +	u8 reg, values[2];
> +	int ret;
> +
> +	switch (info) {
> +	case IIO_EV_INFO_VALUE:
> +		reg = (dir == IIO_EV_DIR_RISING) ?
> +				ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel) :
> +				ADS71x8_REG_LOW_TH_CNT_CH(chan->channel);
> +		ret = ads71x8_i2c_read_block(data->client, reg, values,
> +					     ARRAY_SIZE(values));
> +		if (ret)
> +			return ret;
> +
> +		*val = ((values[1] << 4) | (values[0] >> 4));
> +		return IIO_VAL_INT;
> +	case IIO_EV_INFO_HYSTERESIS:
> +		ret = ads71x8_i2c_read(data->client,
> +				       ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel));
> +		if (ret < 0)
> +			return ret;
> +
> +		*val = (ret & ~ADS71x8_THRESHOLD_LSB_MASK);

Brackets don't add much, so drop them in cases like this.

> +		return IIO_VAL_INT;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int ads71x8_write_event(struct iio_dev *indio_dev,
> +			       const struct iio_chan_spec *chan,
> +			       enum iio_event_type type,
> +			       enum iio_event_direction dir,
> +			       enum iio_event_info info, int val, int val2)
> +{
> +	struct ads71x8_data *data = iio_priv(indio_dev);
> +	u8 reg, values[2];
> +	int ret;
> +
> +	switch (info) {
> +	case IIO_EV_INFO_VALUE: {
> +		if (val >= BIT(12) || val < 0)
> +			return -EINVAL;
> +
> +		reg = (dir == IIO_EV_DIR_RISING) ?
> +				ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel) :

For these cases indent by just one tab more than the line above.

> +				ADS71x8_REG_LOW_TH_CNT_CH(chan->channel);
> +
> +		guard(mutex)(&data->lock);
> +		ret = ads71x8_i2c_read(data->client, reg);
> +		if (ret < 0)
> +			return ret;
> +
> +		values[0] = ret & ~ADS71x8_THRESHOLD_LSB_MASK;
> +		values[0] |= FIELD_PREP(ADS71x8_THRESHOLD_LSB_MASK, val);
> +		values[1] = (val >> 4);
> +		return ads71x8_i2c_write_block(data->client, reg, values,
> +					       ARRAY_SIZE(values));
> +	}
> +	case IIO_EV_INFO_HYSTERESIS: {
> +		if (val >= BIT(4) || val < 0)
> +			return -EINVAL;
> +
> +		reg = ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel);
> +
> +		guard(mutex)(&data->lock);
> +		ret = ads71x8_i2c_read(data->client, reg);
> +		if (ret < 0)
> +			return ret;
> +
> +		values[0] = val & ~ADS71x8_THRESHOLD_LSB_MASK;
> +		values[0] |= FIELD_PREP(ADS71x8_THRESHOLD_LSB_MASK, ret >> 4);
> +		return ads71x8_i2c_write(data->client, reg, values[0]);
> +	}
> +	default:
> +		return -EINVAL;
> +	}
> +}



> +static irqreturn_t ads71x8_event_handler(int irq, void *priv)
> +{
> +	struct iio_dev *indio_dev = priv;
> +	struct ads71x8_data *data = iio_priv(indio_dev);
> +	u8 i, events_high, events_low;
> +	u64 code;
> +	int ret;
> +
> +	/* Check if interrupt was trigger by us */
> +	ret = ads71x8_i2c_read(data->client, ADS71x8_REG_EVENT_FLAG);
> +	if (ret <= 0)
> +		return IRQ_NONE;
> +
> +	ret = ads71x8_i2c_read(data->client, ADS71x8_REG_EVENT_HIGH_FLAG);
> +	if (ret < 0) {
> +		dev_warn(&data->client->dev,

I would add a local
	struct device *dev = &data->client->dev;
given it's used a few times.

> +			 "Failed to read event high flags: %d\n", ret);
> +		return IRQ_HANDLED;
> +	}
> +	events_high = ret;
> +
> +	ret = ads71x8_i2c_read(data->client, ADS71x8_REG_EVENT_LOW_FLAG);
> +	if (ret < 0) {
> +		dev_warn(&data->client->dev,
> +			 "Failed to read event low flags: %d\n", ret);
> +		return IRQ_HANDLED;
> +	}
> +	events_low = ret;
> +
> +	for (i = 0; i < data->chip_data->channel_num; i++) {
> +		if (events_high & BIT(i)) {
> +			code = IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
> +						    IIO_EV_TYPE_THRESH,
> +						    IIO_EV_DIR_RISING);
> +			iio_push_event(indio_dev, code,
> +				       iio_get_time_ns(indio_dev));
> +		}
> +		if (events_low & BIT(i)) {
> +			code = IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
> +						    IIO_EV_TYPE_THRESH,
> +						    IIO_EV_DIR_FALLING);
> +			iio_push_event(indio_dev, code,
> +				       iio_get_time_ns(indio_dev));
> +		}
> +	}
> +
> +	/* Try to clear all interrupt flags */
> +	ret = ads71x8_i2c_write(data->client, ADS71x8_REG_EVENT_HIGH_FLAG, 0xFF);
> +	if (ret)
> +		dev_warn(&data->client->dev,
> +			 "Failed to clear event high flags: %d\n", ret);
> +
> +	ret = ads71x8_i2c_write(data->client, ADS71x8_REG_EVENT_LOW_FLAG, 0xFF);
> +	if (ret)
> +		dev_warn(&data->client->dev,
> +			 "Failed to clear event low flags: %d\n", ret);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int ads71x8_set_conv_mode(struct ads71x8_data *data,
> +				 enum ads71x8_modes mode)
> +{
> +	if (mode == ADS71x8_MODE_AUTO)
> +		return ads71x8_i2c_set_bit(data->client, ADS71x8_REG_OPMODE_CFG,
> +					   ADS71x8_OPMODE_CFG_CONV_MODE);
> +	return ads71x8_i2c_clear_bit(data->client, ADS71x8_REG_OPMODE_CFG,
> +				     ADS71x8_OPMODE_CFG_CONV_MODE);
> +}
> +
> +static int ads7138_init_hw(struct ads71x8_data *data)
> +{
> +	int ret;
> +
> +	data->vref_regu = devm_regulator_get_optional(&data->client->dev, "avdd");

avdd isn't optional. We need the power!  As such I'd not paper over the lack
of it being available.  To avoid weird effects on reading the scale later,
you may want to do a read here so that we can error out if a stub regulator
has been provided.


> +	if (IS_ERR(data->vref_regu))
> +		data->vref_regu = NULL;
> +
> +	/* Reset the chip to get a defined starting configuration */
> +	ret = ads71x8_i2c_set_bit(data->client, ADS71x8_REG_GENERAL_CFG,
> +				  ADS71x8_GENERAL_CFG_RST);
> +	if (ret)
> +		return ret;
> +
> +	ret = ads71x8_set_conv_mode(data, ADS71x8_MODE_AUTO);
> +	if (ret)
> +		return ret;
> +
> +	/* Enable statistics and digital window comparator */
> +	ret = ads71x8_i2c_set_bit(data->client, ADS71x8_REG_GENERAL_CFG,
> +				  (ADS71x8_GENERAL_CFG_STATS_EN |
> +				   ADS71x8_GENERAL_CFG_DWC_EN));

The inner brackets don't add much to readability so I'd be tempted to drop them.

> +	if (ret)
> +		return ret;
> +
> +	/* Enable all channels for auto sequencing */
> +	ret = ads71x8_i2c_set_bit(data->client, ADS71x8_REG_AUTO_SEQ_CH_SEL, 0xFF);
> +	if (ret)
> +		return ret;
> +
> +	/* Set auto sequence mode and start sequencing */
> +	return ads71x8_i2c_set_bit(data->client, ADS71x8_REG_SEQUENCE_CFG,
> +				   (ADS71x8_SEQUENCE_CFG_SEQ_START |
> +				    ADS71x8_SEQUENCE_CFG_SEQ_MODE));
> +}
> +
> +static int ads71x8_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct iio_dev *indio_dev;
> +	struct ads71x8_data *data;
> +	int ret = 0;

Value not used so drop setting it here.

> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	data = iio_priv(indio_dev);
> +	data->client = client;
> +	data->chip_data = i2c_get_match_data(client);
> +	if (!data->chip_data)
> +		return -ENODEV;
> +
> +	ret = devm_mutex_init(dev, &data->lock);
> +	if (ret)
> +		return ret;
> +
> +	indio_dev->name = data->chip_data->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = ads71x8_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(ads71x8_channels);
> +	indio_dev->info = &ti_ads71x8_info;
> +
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	if (client->irq > 0) {
> +		ret = devm_request_threaded_irq(dev, client->irq,
> +						NULL, ads71x8_event_handler,
> +						IRQF_TRIGGER_LOW |
> +						IRQF_ONESHOT | IRQF_SHARED,
> +						client->name, indio_dev);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = ads7138_init_hw(data);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to initialize device\n");
> +
> +	ret = devm_iio_device_register(dev, indio_dev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to register iio device\n");
> +
> +	return 0;
> +}

> +
> +static const struct dev_pm_ops ads71x8_pm_ops = {
> +	RUNTIME_PM_OPS(ads71x8_runtime_suspend, ads71x8_runtime_resume, NULL)

Given it's likely that the runtime pm ops are better than nothing in
suspend and resume cases as well could we make this
DEFINE_RUNTIME_PM_OPS() which uses the runtime ops for those
cases as well?


> +};
Sperling, Tobias Feb. 12, 2025, 12:23 p.m. UTC | #2
Hi Jonathan,

I'll change the things you've mentioned. Just some comments inline.

Regards,
Tobias

> Von: Jonathan Cameron <jic23@kernel.org>
> Gesendet: Samstag, 8. Februar 2025 16:05
> 
> > From: Tobias Sperling <tobias.sperling@softing.com>
> >
> > Add driver for ADS7128 and ADS7138 12-bit, 8-channel analog-to-digital
> > converters. These ADCs have a wide operating range and a wide feature
> > set. Communication is based on the I2C interface.
> > ADS7128 differs in the addition of further hardware features, like a
> > root-mean-square (RMS) and a zero-crossing-detect (ZCD) module.
> >
> > Signed-off-by: Tobias Sperling <tobias.sperling@softing.com>
> 
> Hi Tobias,
> 
> Minor comments below and one question about power management
> 
> Thanks,
> 
> Jonathan
> 
> 
> > +static int ads71x8_i2c_write(const struct i2c_client *client, u8 reg, u8 value)
> > +{
> > +	return ads71x8_i2c_write_block(client, reg, &value, sizeof(value));
> 
> Maybe this should use the single register write (figure 35) rather than bulk one?
> It makes no real difference though other than different opcode.

Yeah can be done, but as there's no difference I didn't want to introduce yet
another function just for single writes. However, as you mentioned below,
ads71x8_i2c_setclear_bit() can be used for that, too. So I'll change that.

> > +}
> > +
> > +static int ads71x8_i2c_setclear_bit(const struct i2c_client *client, u8 reg,
> > +				    u8 bits, u8 opcode)
> 
> > +{
> > +	u8 buf[3] = { opcode, reg, bits };
> > +	int ret;
> > +
> > +	ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
> > +	if (ret < 0)
> > +		return ret;
> > +	if (ret != ARRAY_SIZE(buf))
> > +		return -EIO;
> > +
> > +	return 0;
> > +}
> 
> Whilst this is currently just used for setclear_bit, it is slightly more general
> so maybe the name should reflect that it could be used for single register
> writes for instance.  Naming is hard though and I can't immediately think
> what name covers this combination.

Having something like _write_single_reg_with_opcode() in mind.

> > +static int ads7138_init_hw(struct ads71x8_data *data)
> > +{
> > +	int ret;
> > +
> > +	data->vref_regu = devm_regulator_get_optional(&data->client->dev,
> "avdd");
> 
> avdd isn't optional. We need the power!  As such I'd not paper over the lack
> of it being available.  To avoid weird effects on reading the scale later,
> you may want to do a read here so that we can error out if a stub regulator
> has been provided.

Ok, just wanted to add flexibility for the enduser to not having to define it
in the DTS, but right, AVDD needs to be connected physically. Will change
accordingly.

> > +
> > +static const struct dev_pm_ops ads71x8_pm_ops = {
> > +	RUNTIME_PM_OPS(ads71x8_runtime_suspend,
> ads71x8_runtime_resume, NULL)
> 
> Given it's likely that the runtime pm ops are better than nothing in
> suspend and resume cases as well could we make this
> DEFINE_RUNTIME_PM_OPS() which uses the runtime ops for those
> cases as well?
> 

Yes, looks like DEFINE_RUNTIME_DEV_PM_OPS() can be used to use
these functions for the other cases, too.

> 
> > +};
Jonathan Cameron Feb. 16, 2025, 2:14 p.m. UTC | #3
On Wed, 12 Feb 2025 12:23:15 +0000
"Sperling, Tobias" <Tobias.Sperling@Softing.com> wrote:

> Hi Jonathan,
> 
> I'll change the things you've mentioned. Just some comments inline.
> 
> Regards,
> Tobias
> 
> > Von: Jonathan Cameron <jic23@kernel.org>
> > Gesendet: Samstag, 8. Februar 2025 16:05
> >   
> > > From: Tobias Sperling <tobias.sperling@softing.com>
> > >
> > > Add driver for ADS7128 and ADS7138 12-bit, 8-channel analog-to-digital
> > > converters. These ADCs have a wide operating range and a wide feature
> > > set. Communication is based on the I2C interface.
> > > ADS7128 differs in the addition of further hardware features, like a
> > > root-mean-square (RMS) and a zero-crossing-detect (ZCD) module.
> > >
> > > Signed-off-by: Tobias Sperling <tobias.sperling@softing.com>  
> > 
> > Hi Tobias,
> > 
> > Minor comments below and one question about power management
> > 
> > Thanks,
> > 
> > Jonathan
> > 
> >   
> > > +static int ads71x8_i2c_write(const struct i2c_client *client, u8 reg, u8 value)
> > > +{
> > > +	return ads71x8_i2c_write_block(client, reg, &value, sizeof(value));  
> > 
> > Maybe this should use the single register write (figure 35) rather than bulk one?
> > It makes no real difference though other than different opcode.  
> 
> Yeah can be done, but as there's no difference I didn't want to introduce yet
> another function just for single writes. However, as you mentioned below,
> ads71x8_i2c_setclear_bit() can be used for that, too. So I'll change that.
> 
> > > +}
> > > +
> > > +static int ads71x8_i2c_setclear_bit(const struct i2c_client *client, u8 reg,
> > > +				    u8 bits, u8 opcode)  
> >   
> > > +{
> > > +	u8 buf[3] = { opcode, reg, bits };
> > > +	int ret;
> > > +
> > > +	ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
> > > +	if (ret < 0)
> > > +		return ret;
> > > +	if (ret != ARRAY_SIZE(buf))
> > > +		return -EIO;
> > > +
> > > +	return 0;
> > > +}  
> > 
> > Whilst this is currently just used for setclear_bit, it is slightly more general
> > so maybe the name should reflect that it could be used for single register
> > writes for instance.  Naming is hard though and I can't immediately think
> > what name covers this combination.  
> 
> Having something like _write_single_reg_with_opcode() in mind.
> 
> > > +static int ads7138_init_hw(struct ads71x8_data *data)
> > > +{
> > > +	int ret;
> > > +
> > > +	data->vref_regu = devm_regulator_get_optional(&data->client->dev,  
> > "avdd");
> > 
> > avdd isn't optional. We need the power!  As such I'd not paper over the lack
> > of it being available.  To avoid weird effects on reading the scale later,
> > you may want to do a read here so that we can error out if a stub regulator
> > has been provided.  
> 
> Ok, just wanted to add flexibility for the enduser to not having to define it
> in the DTS, but right, AVDD needs to be connected physically. Will change
> accordingly.

In most cases they will have that flexibility anyway.  It is normally
fine to not provide regulators.
The regulator core just provides a stub regulator instead that
represents an always on supply of unknown characteristics.

> 
> > > +
> > > +static const struct dev_pm_ops ads71x8_pm_ops = {
> > > +	RUNTIME_PM_OPS(ads71x8_runtime_suspend,  
> > ads71x8_runtime_resume, NULL)
> > 
> > Given it's likely that the runtime pm ops are better than nothing in
> > suspend and resume cases as well could we make this
> > DEFINE_RUNTIME_PM_OPS() which uses the runtime ops for those
> > cases as well?
> >   
> 
> Yes, looks like DEFINE_RUNTIME_DEV_PM_OPS() can be used to use
> these functions for the other cases, too.
> 
> >   
> > > +};
diff mbox series

Patch

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 849c90203071a77ec7d94cec06d4378ece44440b..c43277305a126c498f97e843c05747fddb705e9a 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1467,6 +1467,16 @@  config TI_ADS1119
          This driver can also be built as a module. If so, the module will be
          called ti-ads1119.
 
+config TI_ADS7138
+	tristate "Texas Instruments ADS7128 and ADS7138 ADC driver"
+	depends on I2C
+	help
+	  If you say yes here you get support for Texas Instruments ADS7128 and
+	  ADS7138 8-channel A/D converters with 12-bit resolution.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called ti-ads7138.
+
 config TI_ADS7924
 	tristate "Texas Instruments ADS7924 ADC"
 	depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index ee19afba62b7fe0a68309c16f3581d98c5b8f653..1e71d8eb6406b92e5d8e99d556c38858a8b9b640 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -133,6 +133,7 @@  obj-$(CONFIG_TI_ADS1119) += ti-ads1119.o
 obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
 obj-$(CONFIG_TI_ADS1298) += ti-ads1298.o
 obj-$(CONFIG_TI_ADS131E08) += ti-ads131e08.o
+obj-$(CONFIG_TI_ADS7138) += ti-ads7138.o
 obj-$(CONFIG_TI_ADS7924) += ti-ads7924.o
 obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
 obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o
diff --git a/drivers/iio/adc/ti-ads7138.c b/drivers/iio/adc/ti-ads7138.c
new file mode 100644
index 0000000000000000000000000000000000000000..16d9ae7426522ddad62fd78ac6138aab6ab41101
--- /dev/null
+++ b/drivers/iio/adc/ti-ads7138.c
@@ -0,0 +1,746 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ADS7138 - Texas Instruments Analog-to-Digital Converter
+ */
+
+#include <linux/bitfield.h>
+#include <linux/cleanup.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/unaligned.h>
+
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+
+/* AVDD (VREF) operating range in millivolts */
+#define ADS71x8_AVDD_MV_MIN		2350
+#define ADS71x8_AVDD_MV_MAX		5500
+
+/*
+ * Always assume 16 bits resolution as HW registers are aligned like that and
+ * with enabled oversampling/averaging it actually corresponds to 16 bits.
+ */
+#define ADS71x8_RES_BITS		16
+
+/* ADS71x8 operation codes */
+#define ADS71x8_OPCODE_SET_BIT		0x18
+#define ADS71x8_OPCODE_CLEAR_BIT	0x20
+#define ADS71x8_OPCODE_BLOCK_WRITE	0x28
+#define ADS71x8_OPCODE_BLOCK_READ	0x30
+
+/* ADS71x8 registers */
+#define ADS71x8_REG_GENERAL_CFG		0x01
+#define ADS71x8_REG_OSR_CFG		0x03
+#define ADS71x8_REG_OPMODE_CFG		0x04
+#define ADS71x8_REG_SEQUENCE_CFG	0x10
+#define ADS71x8_REG_AUTO_SEQ_CH_SEL	0x12
+#define ADS71x8_REG_ALERT_CH_SEL	0x14
+#define ADS71x8_REG_EVENT_FLAG		0x18
+#define ADS71x8_REG_EVENT_HIGH_FLAG	0x1A
+#define ADS71x8_REG_EVENT_LOW_FLAG	0x1C
+#define ADS71x8_REG_HIGH_TH_HYS_CH(x)	((x) * 4 + 0x20)
+#define ADS71x8_REG_LOW_TH_CNT_CH(x)	((x) * 4 + 0x22)
+#define ADS71x8_REG_MAX_LSB_CH(x)	((x) * 2 + 0x60)
+#define ADS71x8_REG_MIN_LSB_CH(x)	((x) * 2 + 0x80)
+#define ADS71x8_REG_RECENT_LSB_CH(x)	((x) * 2 + 0xA0)
+
+#define ADS71x8_GENERAL_CFG_RST		BIT(0)
+#define ADS71x8_GENERAL_CFG_DWC_EN	BIT(4)
+#define ADS71x8_GENERAL_CFG_STATS_EN	BIT(5)
+#define ADS71x8_OSR_CFG_MASK		GENMASK(2, 0)
+#define ADS71x8_OPMODE_CFG_CONV_MODE	BIT(5)
+#define ADS71x8_OPMODE_CFG_FREQ_MASK	GENMASK(4, 0)
+#define ADS71x8_SEQUENCE_CFG_SEQ_MODE	BIT(0)
+#define ADS71x8_SEQUENCE_CFG_SEQ_START	BIT(4)
+#define ADS71x8_THRESHOLD_LSB_MASK	GENMASK(7, 4)
+
+enum ads71x8_modes {
+	ADS71x8_MODE_MANUAL,
+	ADS71x8_MODE_AUTO,
+};
+
+struct ads71x8_chip_data {
+	const char *name;
+	const int channel_num;
+};
+
+struct ads71x8_data {
+	/* Protects RMW access to the I2C interface */
+	struct mutex lock;
+	struct i2c_client *client;
+	struct regulator *vref_regu;
+	const struct ads71x8_chip_data *chip_data;
+};
+
+static const int ads71x8_samp_freqs_bits[2][26] = {
+	{
+		163, 244, 326, 488, 651, 977, 1302, 1953,
+		2604, 3906, 5208, 7813, 10417, 15625, 20833, 31250,
+		41667, 62500, 83333, 125000, 166667, 250000, 333333, 500000,
+		666667, 1000000
+	}, {
+		0x1f, 0x1e, 0x1d, 0x1c, 0x1b, 0x1a, 0x19, 0x18,
+		0x17, 0x16, 0x15, 0x14, 0x13, 0x12, 0x11, 0x10,
+		/* Here is a hole, due to duplicate frequencies */
+		0x09, 0x08, 0x07, 0x06, 0x05, 0x04, 0x03, 0x02,
+		0x01, 0x00
+	}
+};
+
+static const int ads71x8_oversampling_ratios[] = {
+	1, 2, 4, 8, 16, 32, 64, 128
+};
+
+static int ads71x8_i2c_write_block(const struct i2c_client *client, u8 reg,
+				   u8 *values, u8 length)
+{
+	int ret;
+	int len = length + 2; /* "+ 2" for OPCODE and reg */
+
+	u8 *buf __free(kfree) = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	buf[0] = ADS71x8_OPCODE_BLOCK_WRITE;
+	buf[1] = reg;
+	memcpy(&buf[2], values, length);
+
+	ret = i2c_master_send(client, buf, len);
+	if (ret < 0)
+		return ret;
+	if (ret != len)
+		return -EIO;
+
+	return 0;
+}
+
+static int ads71x8_i2c_write(const struct i2c_client *client, u8 reg, u8 value)
+{
+	return ads71x8_i2c_write_block(client, reg, &value, sizeof(value));
+}
+
+static int ads71x8_i2c_setclear_bit(const struct i2c_client *client, u8 reg,
+				    u8 bits, u8 opcode)
+{
+	u8 buf[3] = { opcode, reg, bits };
+	int ret;
+
+	ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
+	if (ret < 0)
+		return ret;
+	if (ret != ARRAY_SIZE(buf))
+		return -EIO;
+
+	return 0;
+}
+
+static int ads71x8_i2c_set_bit(const struct i2c_client *client, u8 reg, u8 bits)
+{
+	return ads71x8_i2c_setclear_bit(client, reg, bits,
+					ADS71x8_OPCODE_SET_BIT);
+}
+
+static int ads71x8_i2c_clear_bit(const struct i2c_client *client, u8 reg, u8 bits)
+{
+	return ads71x8_i2c_setclear_bit(client, reg, bits,
+					ADS71x8_OPCODE_CLEAR_BIT);
+}
+
+static int ads71x8_i2c_read_block(const struct i2c_client *client, u8 reg,
+				  u8 *out_values, u8 length)
+{
+	u8 buf[2] = { ADS71x8_OPCODE_BLOCK_READ, reg };
+	int ret;
+	struct i2c_msg msgs[] = {
+		{
+			.addr = client->addr,
+			.len = ARRAY_SIZE(buf),
+			.buf = buf,
+		},
+		{
+			.addr = client->addr,
+			.flags = I2C_M_RD,
+			.len = length,
+			.buf = out_values,
+		},
+	};
+
+	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return ret;
+	if (ret != ARRAY_SIZE(msgs))
+		return -EIO;
+
+	return 0;
+}
+
+static int ads71x8_i2c_read(const struct i2c_client *client, u8 reg)
+{
+	u8 value;
+	int ret;
+
+	ret = ads71x8_i2c_read_block(client, reg, &value, sizeof(value));
+	if (ret)
+		return ret;
+	return value;
+}
+
+static int ads71x8_freq_to_bits(int freq)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ads71x8_samp_freqs_bits[0]); i++)
+		if (freq == ads71x8_samp_freqs_bits[0][i])
+			return ads71x8_samp_freqs_bits[1][i];
+
+	return -EINVAL;
+}
+
+static int ads71x8_bits_to_freq(int bits)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ads71x8_samp_freqs_bits[1]); i++)
+		if (bits == ads71x8_samp_freqs_bits[1][i])
+			return ads71x8_samp_freqs_bits[0][i];
+
+	return -EINVAL;
+}
+
+static int ads71x8_osr_to_bits(int osr)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ads71x8_oversampling_ratios); i++)
+		if (osr == ads71x8_oversampling_ratios[i])
+			return i;
+
+	return -EINVAL;
+}
+
+static int ads71x8_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	struct ads71x8_data *data = iio_priv(indio_dev);
+	int ret, vref, bits;
+	u8 values[2];
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = ads71x8_i2c_read_block(data->client,
+					     ADS71x8_REG_RECENT_LSB_CH(chan->channel),
+					     values, ARRAY_SIZE(values));
+		if (ret)
+			return ret;
+
+		*val = get_unaligned_le16(values);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_PEAK:
+		ret = ads71x8_i2c_read_block(data->client,
+					     ADS71x8_REG_MAX_LSB_CH(chan->channel),
+					     values, ARRAY_SIZE(values));
+		if (ret)
+			return ret;
+
+		*val = get_unaligned_le16(values);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_TROUGH:
+		ret = ads71x8_i2c_read_block(data->client,
+					     ADS71x8_REG_MIN_LSB_CH(chan->channel),
+					     values, ARRAY_SIZE(values));
+		if (ret)
+			return ret;
+
+		*val = get_unaligned_le16(values);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = ads71x8_i2c_read(data->client, ADS71x8_REG_OPMODE_CFG);
+		if (ret < 0)
+			return ret;
+
+		bits = FIELD_GET(ADS71x8_OPMODE_CFG_FREQ_MASK, ret);
+		*val = ads71x8_bits_to_freq(bits);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		if (data->vref_regu) {
+			vref = regulator_get_voltage(data->vref_regu);
+			if (vref < 0)
+				return vref;
+			*val = vref / 1000;
+		} else {
+			*val = ADS71x8_AVDD_MV_MIN;
+		}
+		*val2 = ADS71x8_RES_BITS;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		ret = ads71x8_i2c_read(data->client, ADS71x8_REG_OSR_CFG);
+		if (ret < 0)
+			return ret;
+
+		bits = FIELD_GET(ADS71x8_OSR_CFG_MASK, ret);
+		*val = ads71x8_oversampling_ratios[bits];
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ads71x8_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int val,
+			     int val2, long mask)
+{
+	struct ads71x8_data *data = iio_priv(indio_dev);
+	int bits, ret;
+	u8 value;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ: {
+		bits = ads71x8_freq_to_bits(val);
+		if (bits < 0)
+			return bits;
+
+		guard(mutex)(&data->lock);
+		ret = ads71x8_i2c_read(data->client, ADS71x8_REG_OPMODE_CFG);
+		if (ret < 0)
+			return ret;
+
+		value = ret & ~ADS71x8_OPMODE_CFG_FREQ_MASK;
+		value |= FIELD_PREP(ADS71x8_OPMODE_CFG_FREQ_MASK, bits);
+		return ads71x8_i2c_write(data->client, ADS71x8_REG_OPMODE_CFG,
+					 value);
+	}
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		bits = ads71x8_osr_to_bits(val);
+		if (bits < 0)
+			return bits;
+
+		return ads71x8_i2c_write(data->client, ADS71x8_REG_OSR_CFG,
+					 bits);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ads71x8_read_event(struct iio_dev *indio_dev,
+			      const struct iio_chan_spec *chan,
+			      enum iio_event_type type,
+			      enum iio_event_direction dir,
+			      enum iio_event_info info, int *val, int *val2)
+{
+	struct ads71x8_data *data = iio_priv(indio_dev);
+	u8 reg, values[2];
+	int ret;
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		reg = (dir == IIO_EV_DIR_RISING) ?
+				ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel) :
+				ADS71x8_REG_LOW_TH_CNT_CH(chan->channel);
+		ret = ads71x8_i2c_read_block(data->client, reg, values,
+					     ARRAY_SIZE(values));
+		if (ret)
+			return ret;
+
+		*val = ((values[1] << 4) | (values[0] >> 4));
+		return IIO_VAL_INT;
+	case IIO_EV_INFO_HYSTERESIS:
+		ret = ads71x8_i2c_read(data->client,
+				       ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel));
+		if (ret < 0)
+			return ret;
+
+		*val = (ret & ~ADS71x8_THRESHOLD_LSB_MASK);
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ads71x8_write_event(struct iio_dev *indio_dev,
+			       const struct iio_chan_spec *chan,
+			       enum iio_event_type type,
+			       enum iio_event_direction dir,
+			       enum iio_event_info info, int val, int val2)
+{
+	struct ads71x8_data *data = iio_priv(indio_dev);
+	u8 reg, values[2];
+	int ret;
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE: {
+		if (val >= BIT(12) || val < 0)
+			return -EINVAL;
+
+		reg = (dir == IIO_EV_DIR_RISING) ?
+				ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel) :
+				ADS71x8_REG_LOW_TH_CNT_CH(chan->channel);
+
+		guard(mutex)(&data->lock);
+		ret = ads71x8_i2c_read(data->client, reg);
+		if (ret < 0)
+			return ret;
+
+		values[0] = ret & ~ADS71x8_THRESHOLD_LSB_MASK;
+		values[0] |= FIELD_PREP(ADS71x8_THRESHOLD_LSB_MASK, val);
+		values[1] = (val >> 4);
+		return ads71x8_i2c_write_block(data->client, reg, values,
+					       ARRAY_SIZE(values));
+	}
+	case IIO_EV_INFO_HYSTERESIS: {
+		if (val >= BIT(4) || val < 0)
+			return -EINVAL;
+
+		reg = ADS71x8_REG_HIGH_TH_HYS_CH(chan->channel);
+
+		guard(mutex)(&data->lock);
+		ret = ads71x8_i2c_read(data->client, reg);
+		if (ret < 0)
+			return ret;
+
+		values[0] = val & ~ADS71x8_THRESHOLD_LSB_MASK;
+		values[0] |= FIELD_PREP(ADS71x8_THRESHOLD_LSB_MASK, ret >> 4);
+		return ads71x8_i2c_write(data->client, reg, values[0]);
+	}
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ads71x8_read_event_config(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir)
+{
+	struct ads71x8_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (dir != IIO_EV_DIR_EITHER)
+		return -EINVAL;
+
+	ret = ads71x8_i2c_read(data->client, ADS71x8_REG_ALERT_CH_SEL);
+	if (ret < 0)
+		return ret;
+
+	return (ret & BIT(chan->channel)) ? 1 : 0;
+}
+
+static int ads71x8_write_event_config(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan,
+				      enum iio_event_type type,
+				      enum iio_event_direction dir, bool state)
+{
+	struct ads71x8_data *data = iio_priv(indio_dev);
+
+	if (dir != IIO_EV_DIR_EITHER)
+		return -EINVAL;
+
+	if (state)
+		return ads71x8_i2c_set_bit(data->client,
+					   ADS71x8_REG_ALERT_CH_SEL,
+					   BIT(chan->channel));
+	else
+		return ads71x8_i2c_clear_bit(data->client,
+					     ADS71x8_REG_ALERT_CH_SEL,
+					     BIT(chan->channel));
+}
+
+static int ads71x8_read_avail(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      const int **vals, int *type, int *length,
+			      long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*vals = ads71x8_samp_freqs_bits[0];
+		*length = ARRAY_SIZE(ads71x8_samp_freqs_bits[0]);
+		*type = IIO_VAL_INT;
+
+		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*vals = ads71x8_oversampling_ratios;
+		*length = ARRAY_SIZE(ads71x8_oversampling_ratios);
+		*type = IIO_VAL_INT;
+
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ti_ads71x8_info = {
+	.read_raw = &ads71x8_read_raw,
+	.read_avail = &ads71x8_read_avail,
+	.write_raw = &ads71x8_write_raw,
+	.read_event_value = &ads71x8_read_event,
+	.write_event_value = &ads71x8_write_event,
+	.read_event_config = &ads71x8_read_event_config,
+	.write_event_config = &ads71x8_write_event_config,
+};
+
+static const struct iio_event_spec ads71x8_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE)
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_HYSTERESIS) |
+				 BIT(IIO_EV_INFO_ENABLE),
+	},
+};
+
+#define ADS71x8_V_CHAN(_chan) {						\
+	.type = IIO_VOLTAGE,						\
+	.indexed = 1,							\
+	.channel = _chan,						\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
+			      BIT(IIO_CHAN_INFO_PEAK) |			\
+			      BIT(IIO_CHAN_INFO_TROUGH),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) |	\
+				    BIT(IIO_CHAN_INFO_SCALE) |		\
+				    BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
+	.info_mask_shared_by_type_available =				\
+				BIT(IIO_CHAN_INFO_SAMP_FREQ) |		\
+				BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),	\
+	.datasheet_name = "AIN"#_chan,					\
+	.event_spec = ads71x8_events,					\
+	.num_event_specs = ARRAY_SIZE(ads71x8_events),			\
+}
+
+static const struct iio_chan_spec ads71x8_channels[] = {
+	ADS71x8_V_CHAN(0),
+	ADS71x8_V_CHAN(1),
+	ADS71x8_V_CHAN(2),
+	ADS71x8_V_CHAN(3),
+	ADS71x8_V_CHAN(4),
+	ADS71x8_V_CHAN(5),
+	ADS71x8_V_CHAN(6),
+	ADS71x8_V_CHAN(7),
+};
+
+static irqreturn_t ads71x8_event_handler(int irq, void *priv)
+{
+	struct iio_dev *indio_dev = priv;
+	struct ads71x8_data *data = iio_priv(indio_dev);
+	u8 i, events_high, events_low;
+	u64 code;
+	int ret;
+
+	/* Check if interrupt was trigger by us */
+	ret = ads71x8_i2c_read(data->client, ADS71x8_REG_EVENT_FLAG);
+	if (ret <= 0)
+		return IRQ_NONE;
+
+	ret = ads71x8_i2c_read(data->client, ADS71x8_REG_EVENT_HIGH_FLAG);
+	if (ret < 0) {
+		dev_warn(&data->client->dev,
+			 "Failed to read event high flags: %d\n", ret);
+		return IRQ_HANDLED;
+	}
+	events_high = ret;
+
+	ret = ads71x8_i2c_read(data->client, ADS71x8_REG_EVENT_LOW_FLAG);
+	if (ret < 0) {
+		dev_warn(&data->client->dev,
+			 "Failed to read event low flags: %d\n", ret);
+		return IRQ_HANDLED;
+	}
+	events_low = ret;
+
+	for (i = 0; i < data->chip_data->channel_num; i++) {
+		if (events_high & BIT(i)) {
+			code = IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_RISING);
+			iio_push_event(indio_dev, code,
+				       iio_get_time_ns(indio_dev));
+		}
+		if (events_low & BIT(i)) {
+			code = IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_FALLING);
+			iio_push_event(indio_dev, code,
+				       iio_get_time_ns(indio_dev));
+		}
+	}
+
+	/* Try to clear all interrupt flags */
+	ret = ads71x8_i2c_write(data->client, ADS71x8_REG_EVENT_HIGH_FLAG, 0xFF);
+	if (ret)
+		dev_warn(&data->client->dev,
+			 "Failed to clear event high flags: %d\n", ret);
+
+	ret = ads71x8_i2c_write(data->client, ADS71x8_REG_EVENT_LOW_FLAG, 0xFF);
+	if (ret)
+		dev_warn(&data->client->dev,
+			 "Failed to clear event low flags: %d\n", ret);
+
+	return IRQ_HANDLED;
+}
+
+static int ads71x8_set_conv_mode(struct ads71x8_data *data,
+				 enum ads71x8_modes mode)
+{
+	if (mode == ADS71x8_MODE_AUTO)
+		return ads71x8_i2c_set_bit(data->client, ADS71x8_REG_OPMODE_CFG,
+					   ADS71x8_OPMODE_CFG_CONV_MODE);
+	return ads71x8_i2c_clear_bit(data->client, ADS71x8_REG_OPMODE_CFG,
+				     ADS71x8_OPMODE_CFG_CONV_MODE);
+}
+
+static int ads7138_init_hw(struct ads71x8_data *data)
+{
+	int ret;
+
+	data->vref_regu = devm_regulator_get_optional(&data->client->dev, "avdd");
+	if (IS_ERR(data->vref_regu))
+		data->vref_regu = NULL;
+
+	/* Reset the chip to get a defined starting configuration */
+	ret = ads71x8_i2c_set_bit(data->client, ADS71x8_REG_GENERAL_CFG,
+				  ADS71x8_GENERAL_CFG_RST);
+	if (ret)
+		return ret;
+
+	ret = ads71x8_set_conv_mode(data, ADS71x8_MODE_AUTO);
+	if (ret)
+		return ret;
+
+	/* Enable statistics and digital window comparator */
+	ret = ads71x8_i2c_set_bit(data->client, ADS71x8_REG_GENERAL_CFG,
+				  (ADS71x8_GENERAL_CFG_STATS_EN |
+				   ADS71x8_GENERAL_CFG_DWC_EN));
+	if (ret)
+		return ret;
+
+	/* Enable all channels for auto sequencing */
+	ret = ads71x8_i2c_set_bit(data->client, ADS71x8_REG_AUTO_SEQ_CH_SEL, 0xFF);
+	if (ret)
+		return ret;
+
+	/* Set auto sequence mode and start sequencing */
+	return ads71x8_i2c_set_bit(data->client, ADS71x8_REG_SEQUENCE_CFG,
+				   (ADS71x8_SEQUENCE_CFG_SEQ_START |
+				    ADS71x8_SEQUENCE_CFG_SEQ_MODE));
+}
+
+static int ads71x8_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct iio_dev *indio_dev;
+	struct ads71x8_data *data;
+	int ret = 0;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	data->chip_data = i2c_get_match_data(client);
+	if (!data->chip_data)
+		return -ENODEV;
+
+	ret = devm_mutex_init(dev, &data->lock);
+	if (ret)
+		return ret;
+
+	indio_dev->name = data->chip_data->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ads71x8_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ads71x8_channels);
+	indio_dev->info = &ti_ads71x8_info;
+
+	i2c_set_clientdata(client, indio_dev);
+
+	if (client->irq > 0) {
+		ret = devm_request_threaded_irq(dev, client->irq,
+						NULL, ads71x8_event_handler,
+						IRQF_TRIGGER_LOW |
+						IRQF_ONESHOT | IRQF_SHARED,
+						client->name, indio_dev);
+		if (ret)
+			return ret;
+	}
+
+	ret = ads7138_init_hw(data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to initialize device\n");
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register iio device\n");
+
+	return 0;
+}
+
+static int ads71x8_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ads71x8_data *data = iio_priv(indio_dev);
+
+	return ads71x8_set_conv_mode(data, ADS71x8_MODE_MANUAL);
+}
+
+static int ads71x8_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ads71x8_data *data = iio_priv(indio_dev);
+
+	return ads71x8_set_conv_mode(data, ADS71x8_MODE_AUTO);
+}
+
+static const struct dev_pm_ops ads71x8_pm_ops = {
+	RUNTIME_PM_OPS(ads71x8_runtime_suspend, ads71x8_runtime_resume, NULL)
+};
+
+static const struct ads71x8_chip_data ads7128_data = {
+	.name = "ads7128",
+	.channel_num = 8,
+};
+
+static const struct ads71x8_chip_data ads7138_data = {
+	.name = "ads7138",
+	.channel_num = 8,
+};
+
+static const struct of_device_id ads71x8_of_match[] = {
+	{ .compatible = "ti,ads7128", .data = &ads7128_data },
+	{ .compatible = "ti,ads7138", .data = &ads7138_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ads71x8_of_match);
+
+static const struct i2c_device_id ads71x8_device_ids[] = {
+	{ "ads7128", (kernel_ulong_t)&ads7128_data },
+	{ "ads7138", (kernel_ulong_t)&ads7138_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ads71x8_device_ids);
+
+static struct i2c_driver ads71x8_driver = {
+	.driver = {
+		.name = "ads7138",
+		.of_match_table = ads71x8_of_match,
+		.pm = pm_ptr(&ads71x8_pm_ops),
+	},
+	.id_table = ads71x8_device_ids,
+	.probe = ads71x8_probe,
+};
+module_i2c_driver(ads71x8_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tobias Sperling <tobias.sperling@softing.com>");
+MODULE_DESCRIPTION("Driver for TI ADS71x8 ADCs");