[RESEND,v4,2/4] thermal: k3: Add support for bandgap sensors
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Message ID 20200318083028.9984-3-j-keerthy@ti.com
State New
Delegated to: Daniel Lezcano
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Series
  • thermal: k3: Add support for bandgap sensors
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Commit Message

J, KEERTHY March 18, 2020, 8:30 a.m. UTC
The bandgap provides current and voltage reference for its internal
circuits and other analog IP blocks. The analog-to-digital
converter (ADC) produces an output value that is proportional
to the silicon temperature.

Currently reading temperatures and creating work to periodically
read temperatures from the zones are supported.
There are no active/passive cooling agent supported.

Signed-off-by: Keerthy <j-keerthy@ti.com>
---

Changes in v4:

  * Fixed comments from Daniel to remove trend function.
  * Mostly cleaned up all the unused variables.
  * Driver from bool to tristate.

 drivers/thermal/Kconfig      |  11 ++
 drivers/thermal/Makefile     |   1 +
 drivers/thermal/k3_bandgap.c | 287 +++++++++++++++++++++++++++++++++++
 3 files changed, 299 insertions(+)
 create mode 100644 drivers/thermal/k3_bandgap.c

Comments

Daniel Lezcano March 19, 2020, 12:38 p.m. UTC | #1
On 18/03/2020 09:30, Keerthy wrote:
> The bandgap provides current and voltage reference for its internal
> circuits and other analog IP blocks. The analog-to-digital
> converter (ADC) produces an output value that is proportional
> to the silicon temperature.
> 
> Currently reading temperatures and creating work to periodically
> read temperatures from the zones are supported.
> There are no active/passive cooling agent supported.
> 
> Signed-off-by: Keerthy <j-keerthy@ti.com>
> ---
> 
> Changes in v4:
> 
>   * Fixed comments from Daniel to remove trend function.
>   * Mostly cleaned up all the unused variables.
>   * Driver from bool to tristate.
> 
>  drivers/thermal/Kconfig      |  11 ++
>  drivers/thermal/Makefile     |   1 +
>  drivers/thermal/k3_bandgap.c | 287 +++++++++++++++++++++++++++++++++++
>  3 files changed, 299 insertions(+)
>  create mode 100644 drivers/thermal/k3_bandgap.c
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 5a05db5438d6..d848d9a3c4f1 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -251,6 +251,17 @@ config IMX_THERMAL
>  	  cpufreq is used as the cooling device to throttle CPUs when the
>  	  passive trip is crossed.
>  
> +config K3_THERMAL
> +	tristate "Texas Instruments K3 thermal support"
> +	depends on ARCH_K3 || COMPILE_TEST
> +	help
> +	  If you say yes here you get thermal support for the Texas Instruments
> +	  K3 SoC family. The current chip supported is:
> +	   - AM654
> +
> +	  This includes temperature reading functionality and also trend
> +	  computation.

trend is now removed :)

>  config MAX77620_THERMAL
>  	tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
>  	depends on MFD_MAX77620
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 9fb88e26fb10..5ad6535139ae 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -28,6 +28,7 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL)	+= clock_cooling.o
>  # devfreq cooling
>  thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
>  
> +obj-$(CONFIG_K3_THERMAL)	+= k3_bandgap.o
>  # platform thermal drivers
>  obj-y				+= broadcom/
>  obj-$(CONFIG_THERMAL_MMIO)		+= thermal_mmio.o
> diff --git a/drivers/thermal/k3_bandgap.c b/drivers/thermal/k3_bandgap.c
> new file mode 100644
> index 000000000000..d16e60335721
> --- /dev/null
> +++ b/drivers/thermal/k3_bandgap.c
> @@ -0,0 +1,287 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * TI Bandgap temperature sensor driver for K3 SoC Family
> + *
> + * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/err.h>
> +#include <linux/types.h>
> +#include <linux/spinlock.h>
> +#include <linux/of_platform.h>
> +#include <linux/io.h>
> +#include <linux/workqueue.h>

Please check all the headers are needed, AFAICT workqueue.h and
spinlock.h are not.

> +#include <linux/thermal.h>
> +#include <linux/of.h>
> +
> +#define K3_VTM_DEVINFO_PWR0_OFFSET		0x4
> +#define K3_VTM_DEVINFO_PWR0_CVD_CT_MASK	0xf
> +#define K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK	0xf0
> +#define K3_VTM_TMPSENS0_CTRL_OFFSET	0x80
> +#define K3_VTM_REGS_PER_TS			0x10
> +#define K3_VTM_TS_STAT_DTEMP_MASK	0x3ff
> +#define K3_VTM_MAX_NUM_TS		8
> +#define K3_VTM_TMPSENS_CTRL_CBIASSEL	BIT(0)
> +#define K3_VTM_TMPSENS_CTRL_SOC		BIT(5)
> +#define K3_VTM_TMPSENS_CTRL_CLRZ		BIT(6)
> +#define K3_VTM_TMPSENS_CTRL_CLKON_REQ	BIT(7)
> +
> +#define K3_VTM_ADC_BEGIN_VAL		540
> +#define K3_VTM_ADC_END_VAL		944
> +
> +static const int k3_adc_to_temp[] = {
> +	-40000, -40000, -40000, -40000, -39800, -39400, -39000, -38600, -38200,
> +	-37800, -37400, -37000, -36600, -36200, -35800, -35300, -34700, -34200,
> +	-33800, -33400, -33000, -32600, -32200, -31800, -31400, -31000, -30600,
> +	-30200, -29800, -29400, -29000, -28600, -28200, -27700, -27100, -26600,
> +	-26200, -25800, -25400, -25000, -24600, -24200, -23800, -23400, -23000,
> +	-22600, -22200, -21800, -21400, -21000, -20500, -19900, -19400, -19000,
> +	-18600, -18200, -17800, -17400, -17000, -16600, -16200, -15800, -15400,
> +	-15000, -14600, -14200, -13800, -13400, -13000, -12500, -11900, -11400,
> +	-11000, -10600, -10200, -9800, -9400, -9000, -8600, -8200, -7800, -7400,
> +	-7000, -6600, -6200, -5800, -5400, -5000, -4500, -3900, -3400, -3000,
> +	-2600, -2200, -1800, -1400, -1000, -600, -200, 200, 600, 1000, 1400,
> +	1800, 2200, 2600, 3000, 3400, 3900, 4500, 5000, 5400, 5800, 6200, 6600,
> +	7000, 7400, 7800, 8200, 8600, 9000, 9400, 9800, 10200, 10600, 11000,
> +	11400, 11800, 12200, 12700, 13300, 13800, 14200, 14600, 15000, 15400,
> +	15800, 16200, 16600, 17000, 17400, 17800, 18200, 18600, 19000, 19400,
> +	19800, 20200, 20600, 21000, 21400, 21900, 22500, 23000, 23400, 23800,
> +	24200, 24600, 25000, 25400, 25800, 26200, 26600, 27000, 27400, 27800,
> +	28200, 28600, 29000, 29400, 29800, 30200, 30600, 31000, 31400, 31900,
> +	32500, 33000, 33400, 33800, 34200, 34600, 35000, 35400, 35800, 36200,
> +	36600, 37000, 37400, 37800, 38200, 38600, 39000, 39400, 39800, 40200,
> +	40600, 41000, 41400, 41800, 42200, 42600, 43100, 43700, 44200, 44600,
> +	45000, 45400, 45800, 46200, 46600, 47000, 47400, 47800, 48200, 48600,
> +	49000, 49400, 49800, 50200, 50600, 51000, 51400, 51800, 52200, 52600,
> +	53000, 53400, 53800, 54200, 54600, 55000, 55400, 55900, 56500, 57000,
> +	57400, 57800, 58200, 58600, 59000, 59400, 59800, 60200, 60600, 61000,
> +	61400, 61800, 62200, 62600, 63000, 63400, 63800, 64200, 64600, 65000,
> +	65400, 65800, 66200, 66600, 67000, 67400, 67800, 68200, 68600, 69000,
> +	69400, 69800, 70200, 70600, 71000, 71500, 72100, 72600, 73000, 73400,
> +	73800, 74200, 74600, 75000, 75400, 75800, 76200, 76600, 77000, 77400,
> +	77800, 78200, 78600, 79000, 79400, 79800, 80200, 80600, 81000, 81400,
> +	81800, 82200, 82600, 83000, 83400, 83800, 84200, 84600, 85000, 85400,
> +	85800, 86200, 86600, 87000, 87400, 87800, 88200, 88600, 89000, 89400,
> +	89800, 90200, 90600, 91000, 91400, 91800, 92200, 92600, 93000, 93400,
> +	93800, 94200, 94600, 95000, 95400, 95800, 96200, 96600, 97000, 97500,
> +	98100, 98600, 99000, 99400, 99800, 100200, 100600, 101000, 101400,
> +	101800, 102200, 102600, 103000, 103400, 103800, 104200, 104600, 105000,
> +	105400, 105800, 106200, 106600, 107000, 107400, 107800, 108200, 108600,
> +	109000, 109400, 109800, 110200, 110600, 111000, 111400, 111800, 112200,
> +	112600, 113000, 113400, 113800, 114200, 114600, 115000, 115400, 115800,
> +	116200, 116600, 117000, 117400, 117800, 118200, 118600, 119000, 119400,
> +	119800, 120200, 120600, 121000, 121400, 121800, 122200, 122600, 123000,
> +	123400, 123800, 124200, 124600, 124900, 125000,
> +};

Can be this array replaced by an initialization array with a formula?

Why do we have most of the time a step of 400 then suddenly 500 and 400
again? eg. 30600, 31000, 31400, 31900, 32500, 33000, 33400

> +struct k3_thermal_data;

forward declaration not needed.

> +struct k3_bandgap {
> +	void __iomem *base;
> +	const struct k3_bandgap_data *conf;
> +};
> +
> +/* common data structures */
> +struct k3_thermal_data {
> +	struct thermal_zone_device *ti_thermal;
> +	struct k3_bandgap *bgp;
> +	struct work_struct thermal_wq;
> +	int sensor_id;
> +	u32 ctrl_offset;
> +	u32 stat_offset;
> +	int prev_temp;

prev_temp is assigned but not used.

> +};
> +
> +static unsigned int vtm_get_best_value(unsigned int s0, unsigned int s1,
> +				       unsigned int s2)
> +{
> +	int d01 = abs(s0 - s1);
> +	int d02 = abs(s0 - s2);
> +	int d12 = abs(s1 - s2);
> +
> +	if (d01 <= d02 && d01 <= d12)
> +		return (s0 + s1) / 2;
> +
> +	if (d02 <= d01 && d02 <= d12)
> +		return (s0 + s2) / 2;
> +
> +	return (s1 + s2) / 2;
> +}
> +
> +static int k3_bgp_read_temp(struct k3_thermal_data *devdata,
> +			    int *temp)
> +{
> +	struct k3_bandgap *bgp;
> +	unsigned int dtemp, s0, s1, s2;
> +
> +	bgp = devdata->bgp;
> +
> +	/*
> +	 * Errata is applicable for am654 pg 1.0 silicon. There
> +	 * is a variation of the order for 8-10 degree centigrade.
> +	 * Work around that by getting the average of two closest
> +	 * readings out of three readings everytime we want to
> +	 * report temperatures.
> +	 *
> +	 * Errata workaround.
> +	 */
> +	s0 = readl(bgp->base + devdata->stat_offset) &
> +		K3_VTM_TS_STAT_DTEMP_MASK;
> +	s1 = readl(bgp->base + devdata->stat_offset) &
> +		K3_VTM_TS_STAT_DTEMP_MASK;
> +	s2 = readl(bgp->base + devdata->stat_offset) &
> +		K3_VTM_TS_STAT_DTEMP_MASK;
> +	dtemp = vtm_get_best_value(s0, s1, s2);
> +
> +	if (dtemp < K3_VTM_ADC_BEGIN_VAL || dtemp > K3_VTM_ADC_END_VAL)
> +		return -EINVAL;
> +
> +	*temp = k3_adc_to_temp[dtemp - K3_VTM_ADC_BEGIN_VAL];

To be sure there is not a subtle memory corruption, I would recommend to
check the consistency between K3_VTM_ADC_END_VAL - K3_VTM_ADC_BEGIN_VAL
and the array size at init time.

For example:

if (ARRAY_SIZE(k3_adc_to_temp) !=
	(K3_VTM_ADC_END_VAL - K3_VTM_ADC_BEGIN_VAL))

> +	return 0;
> +}
> +
> +static int k3_thermal_get_temp(void *devdata, int *temp)
> +{
> +	struct k3_thermal_data *data = devdata;
> +	int ret = 0;
> +
> +	ret = k3_bgp_read_temp(data, temp);
> +	if (ret)
> +		return ret;
> +
> +	data->prev_temp = *temp;
> +
> +	return ret;
> +}
> +
> +static const struct thermal_zone_of_device_ops k3_of_thermal_ops = {
> +	.get_temp = k3_thermal_get_temp,
> +};
> +
> +static void k3_thermal_work(struct work_struct *work)
> +{
> +	struct k3_thermal_data *data = container_of(work,
> +					struct k3_thermal_data, thermal_wq);
> +
> +	thermal_zone_device_update(data->ti_thermal, THERMAL_EVENT_UNSPECIFIED);
> +
> +	dev_dbg(&data->ti_thermal->device, "updated thermal zone %s\n",
> +		data->ti_thermal->type);
> +}
> +
> +static const struct of_device_id of_k3_bandgap_match[];
> +
> +static int k3_bandgap_probe(struct platform_device *pdev)
> +{
> +	int ret = 0, cnt, val, id, reg_cnt = 0;
> +	struct resource *res;
> +	struct device *dev = &pdev->dev;
> +	struct k3_bandgap *bgp;
> +	struct k3_thermal_data *data;
> +
> +	bgp = devm_kzalloc(&pdev->dev, sizeof(*bgp), GFP_KERNEL);
> +	if (!bgp)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	bgp->base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(bgp->base))
> +		return PTR_ERR(bgp->base);
> +
> +	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(dev);
> +		pm_runtime_disable(dev);
> +		return ret;
> +	}
> +
> +	/* Get the sensor count in the VTM */
> +	val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
> +	cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
> +	cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
> +
> +	data = devm_kcalloc(dev, cnt, sizeof(*data), GFP_KERNEL);
> +	if (!data) {
> +		ret = -ENOMEM;
> +		goto err_alloc;
> +	}
> +
> +	/* Register the thermal sensors */
> +	for (id = 0; id < cnt; id++) {
> +		data[id].sensor_id = id;
> +		data[id].bgp = bgp;
> +		data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET +
> +					id * K3_VTM_REGS_PER_TS;
> +		data[id].stat_offset = data[id].ctrl_offset + 0x8;
> +		INIT_WORK(&data[id].thermal_wq, k3_thermal_work);

		What is supposed to do ?

> +		val = readl(data[id].bgp->base + data[id].ctrl_offset);
> +		val |= (K3_VTM_TMPSENS_CTRL_SOC |
> +			K3_VTM_TMPSENS_CTRL_CLRZ |
> +			K3_VTM_TMPSENS_CTRL_CLKON_REQ);
> +		val &= ~K3_VTM_TMPSENS_CTRL_CBIASSEL;
> +		writel(val, data[id].bgp->base + data[id].ctrl_offset);
> +
> +		data[id].ti_thermal =
> +		devm_thermal_zone_of_sensor_register(dev, id,
> +						     &data[id],
> +						     &k3_of_thermal_ops);
> +		if (IS_ERR(data[id].ti_thermal)) {
> +			dev_err(dev, "thermal zone device is NULL\n");
> +			ret = PTR_ERR(data[id].ti_thermal);
> +			goto err_alloc;
> +		}
> +
> +		reg_cnt++;
> +
> +		/* Initialize Previous temp */
> +		k3_thermal_get_temp(&data[id], &data[id].prev_temp);
> +	}
> +
> +	platform_set_drvdata(pdev, bgp);
> +
> +	return 0;
> +
> +err_alloc:
> +	pm_runtime_put_sync(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +
> +	return ret;
> +}
> +
> +static int k3_bandgap_remove(struct platform_device *pdev)
> +{
> +	pm_runtime_put_sync(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id of_k3_bandgap_match[] = {
> +	{
> +		.compatible = "ti,am654-vtm",
> +	},
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, of_k3_bandgap_match);
> +
> +static struct platform_driver k3_bandgap_sensor_driver = {
> +	.probe = k3_bandgap_probe,
> +	.remove = k3_bandgap_remove,
> +	.driver = {
> +		.name = "k3-soc-thermal",
> +		.of_match_table	= of_k3_bandgap_match,
> +	},
> +};
> +
> +module_platform_driver(k3_bandgap_sensor_driver);
> +
> +MODULE_DESCRIPTION("K3 bandgap temperature sensor driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("J Keerthy <j-keerthy@ti.com>");
>
J, KEERTHY March 19, 2020, 12:52 p.m. UTC | #2
On 19/03/20 6:08 pm, Daniel Lezcano wrote:
> On 18/03/2020 09:30, Keerthy wrote:
>> The bandgap provides current and voltage reference for its internal
>> circuits and other analog IP blocks. The analog-to-digital
>> converter (ADC) produces an output value that is proportional
>> to the silicon temperature.
>>
>> Currently reading temperatures and creating work to periodically
>> read temperatures from the zones are supported.
>> There are no active/passive cooling agent supported.
>>
>> Signed-off-by: Keerthy <j-keerthy@ti.com>
>> ---
>>
>> Changes in v4:
>>
>>    * Fixed comments from Daniel to remove trend function.
>>    * Mostly cleaned up all the unused variables.
>>    * Driver from bool to tristate.
>>
>>   drivers/thermal/Kconfig      |  11 ++
>>   drivers/thermal/Makefile     |   1 +
>>   drivers/thermal/k3_bandgap.c | 287 +++++++++++++++++++++++++++++++++++
>>   3 files changed, 299 insertions(+)
>>   create mode 100644 drivers/thermal/k3_bandgap.c
>>
>> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
>> index 5a05db5438d6..d848d9a3c4f1 100644
>> --- a/drivers/thermal/Kconfig
>> +++ b/drivers/thermal/Kconfig
>> @@ -251,6 +251,17 @@ config IMX_THERMAL
>>   	  cpufreq is used as the cooling device to throttle CPUs when the
>>   	  passive trip is crossed.
>>   
>> +config K3_THERMAL
>> +	tristate "Texas Instruments K3 thermal support"
>> +	depends on ARCH_K3 || COMPILE_TEST
>> +	help
>> +	  If you say yes here you get thermal support for the Texas Instruments
>> +	  K3 SoC family. The current chip supported is:
>> +	   - AM654
>> +
>> +	  This includes temperature reading functionality and also trend
>> +	  computation.
> 
> trend is now removed :)

Oops missed this one here. I will remove.

> 
>>   config MAX77620_THERMAL
>>   	tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
>>   	depends on MFD_MAX77620
>> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
>> index 9fb88e26fb10..5ad6535139ae 100644
>> --- a/drivers/thermal/Makefile
>> +++ b/drivers/thermal/Makefile
>> @@ -28,6 +28,7 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL)	+= clock_cooling.o
>>   # devfreq cooling
>>   thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
>>   
>> +obj-$(CONFIG_K3_THERMAL)	+= k3_bandgap.o
>>   # platform thermal drivers
>>   obj-y				+= broadcom/
>>   obj-$(CONFIG_THERMAL_MMIO)		+= thermal_mmio.o
>> diff --git a/drivers/thermal/k3_bandgap.c b/drivers/thermal/k3_bandgap.c
>> new file mode 100644
>> index 000000000000..d16e60335721
>> --- /dev/null
>> +++ b/drivers/thermal/k3_bandgap.c
>> @@ -0,0 +1,287 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * TI Bandgap temperature sensor driver for K3 SoC Family
>> + *
>> + * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/err.h>
>> +#include <linux/types.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/io.h>
>> +#include <linux/workqueue.h>
> 
> Please check all the headers are needed, AFAICT workqueue.h and
> spinlock.h are not.

okay

> 
>> +#include <linux/thermal.h>
>> +#include <linux/of.h>
>> +
>> +#define K3_VTM_DEVINFO_PWR0_OFFSET		0x4
>> +#define K3_VTM_DEVINFO_PWR0_CVD_CT_MASK	0xf
>> +#define K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK	0xf0
>> +#define K3_VTM_TMPSENS0_CTRL_OFFSET	0x80
>> +#define K3_VTM_REGS_PER_TS			0x10
>> +#define K3_VTM_TS_STAT_DTEMP_MASK	0x3ff
>> +#define K3_VTM_MAX_NUM_TS		8
>> +#define K3_VTM_TMPSENS_CTRL_CBIASSEL	BIT(0)
>> +#define K3_VTM_TMPSENS_CTRL_SOC		BIT(5)
>> +#define K3_VTM_TMPSENS_CTRL_CLRZ		BIT(6)
>> +#define K3_VTM_TMPSENS_CTRL_CLKON_REQ	BIT(7)
>> +
>> +#define K3_VTM_ADC_BEGIN_VAL		540
>> +#define K3_VTM_ADC_END_VAL		944
>> +
>> +static const int k3_adc_to_temp[] = {
>> +	-40000, -40000, -40000, -40000, -39800, -39400, -39000, -38600, -38200,
>> +	-37800, -37400, -37000, -36600, -36200, -35800, -35300, -34700, -34200,
>> +	-33800, -33400, -33000, -32600, -32200, -31800, -31400, -31000, -30600,
>> +	-30200, -29800, -29400, -29000, -28600, -28200, -27700, -27100, -26600,
>> +	-26200, -25800, -25400, -25000, -24600, -24200, -23800, -23400, -23000,
>> +	-22600, -22200, -21800, -21400, -21000, -20500, -19900, -19400, -19000,
>> +	-18600, -18200, -17800, -17400, -17000, -16600, -16200, -15800, -15400,
>> +	-15000, -14600, -14200, -13800, -13400, -13000, -12500, -11900, -11400,
>> +	-11000, -10600, -10200, -9800, -9400, -9000, -8600, -8200, -7800, -7400,
>> +	-7000, -6600, -6200, -5800, -5400, -5000, -4500, -3900, -3400, -3000,
>> +	-2600, -2200, -1800, -1400, -1000, -600, -200, 200, 600, 1000, 1400,
>> +	1800, 2200, 2600, 3000, 3400, 3900, 4500, 5000, 5400, 5800, 6200, 6600,
>> +	7000, 7400, 7800, 8200, 8600, 9000, 9400, 9800, 10200, 10600, 11000,
>> +	11400, 11800, 12200, 12700, 13300, 13800, 14200, 14600, 15000, 15400,
>> +	15800, 16200, 16600, 17000, 17400, 17800, 18200, 18600, 19000, 19400,
>> +	19800, 20200, 20600, 21000, 21400, 21900, 22500, 23000, 23400, 23800,
>> +	24200, 24600, 25000, 25400, 25800, 26200, 26600, 27000, 27400, 27800,
>> +	28200, 28600, 29000, 29400, 29800, 30200, 30600, 31000, 31400, 31900,
>> +	32500, 33000, 33400, 33800, 34200, 34600, 35000, 35400, 35800, 36200,
>> +	36600, 37000, 37400, 37800, 38200, 38600, 39000, 39400, 39800, 40200,
>> +	40600, 41000, 41400, 41800, 42200, 42600, 43100, 43700, 44200, 44600,
>> +	45000, 45400, 45800, 46200, 46600, 47000, 47400, 47800, 48200, 48600,
>> +	49000, 49400, 49800, 50200, 50600, 51000, 51400, 51800, 52200, 52600,
>> +	53000, 53400, 53800, 54200, 54600, 55000, 55400, 55900, 56500, 57000,
>> +	57400, 57800, 58200, 58600, 59000, 59400, 59800, 60200, 60600, 61000,
>> +	61400, 61800, 62200, 62600, 63000, 63400, 63800, 64200, 64600, 65000,
>> +	65400, 65800, 66200, 66600, 67000, 67400, 67800, 68200, 68600, 69000,
>> +	69400, 69800, 70200, 70600, 71000, 71500, 72100, 72600, 73000, 73400,
>> +	73800, 74200, 74600, 75000, 75400, 75800, 76200, 76600, 77000, 77400,
>> +	77800, 78200, 78600, 79000, 79400, 79800, 80200, 80600, 81000, 81400,
>> +	81800, 82200, 82600, 83000, 83400, 83800, 84200, 84600, 85000, 85400,
>> +	85800, 86200, 86600, 87000, 87400, 87800, 88200, 88600, 89000, 89400,
>> +	89800, 90200, 90600, 91000, 91400, 91800, 92200, 92600, 93000, 93400,
>> +	93800, 94200, 94600, 95000, 95400, 95800, 96200, 96600, 97000, 97500,
>> +	98100, 98600, 99000, 99400, 99800, 100200, 100600, 101000, 101400,
>> +	101800, 102200, 102600, 103000, 103400, 103800, 104200, 104600, 105000,
>> +	105400, 105800, 106200, 106600, 107000, 107400, 107800, 108200, 108600,
>> +	109000, 109400, 109800, 110200, 110600, 111000, 111400, 111800, 112200,
>> +	112600, 113000, 113400, 113800, 114200, 114600, 115000, 115400, 115800,
>> +	116200, 116600, 117000, 117400, 117800, 118200, 118600, 119000, 119400,
>> +	119800, 120200, 120600, 121000, 121400, 121800, 122200, 122600, 123000,
>> +	123400, 123800, 124200, 124600, 124900, 125000,
>> +};
> 
> Can be this array replaced by an initialization array with a formula?
> 
> Why do we have most of the time a step of 400 then suddenly 500 and 400
> again? eg. 30600, 31000, 31400, 31900, 32500, 33000, 33400

This has come from a polynomial equation which i do not want to 
calculate every time we read the temperature. Hence prefer Look up table.

> 
>> +struct k3_thermal_data;
> 
> forward declaration not needed.

okay

> 
>> +struct k3_bandgap {
>> +	void __iomem *base;
>> +	const struct k3_bandgap_data *conf;
>> +};
>> +
>> +/* common data structures */
>> +struct k3_thermal_data {
>> +	struct thermal_zone_device *ti_thermal;
>> +	struct k3_bandgap *bgp;
>> +	struct work_struct thermal_wq;
>> +	int sensor_id;
>> +	u32 ctrl_offset;
>> +	u32 stat_offset;
>> +	int prev_temp;
> 
> prev_temp is assigned but not used.

Yes this can be removed.

> 
>> +};
>> +
>> +static unsigned int vtm_get_best_value(unsigned int s0, unsigned int s1,
>> +				       unsigned int s2)
>> +{
>> +	int d01 = abs(s0 - s1);
>> +	int d02 = abs(s0 - s2);
>> +	int d12 = abs(s1 - s2);
>> +
>> +	if (d01 <= d02 && d01 <= d12)
>> +		return (s0 + s1) / 2;
>> +
>> +	if (d02 <= d01 && d02 <= d12)
>> +		return (s0 + s2) / 2;
>> +
>> +	return (s1 + s2) / 2;
>> +}
>> +
>> +static int k3_bgp_read_temp(struct k3_thermal_data *devdata,
>> +			    int *temp)
>> +{
>> +	struct k3_bandgap *bgp;
>> +	unsigned int dtemp, s0, s1, s2;
>> +
>> +	bgp = devdata->bgp;
>> +
>> +	/*
>> +	 * Errata is applicable for am654 pg 1.0 silicon. There
>> +	 * is a variation of the order for 8-10 degree centigrade.
>> +	 * Work around that by getting the average of two closest
>> +	 * readings out of three readings everytime we want to
>> +	 * report temperatures.
>> +	 *
>> +	 * Errata workaround.
>> +	 */
>> +	s0 = readl(bgp->base + devdata->stat_offset) &
>> +		K3_VTM_TS_STAT_DTEMP_MASK;
>> +	s1 = readl(bgp->base + devdata->stat_offset) &
>> +		K3_VTM_TS_STAT_DTEMP_MASK;
>> +	s2 = readl(bgp->base + devdata->stat_offset) &
>> +		K3_VTM_TS_STAT_DTEMP_MASK;
>> +	dtemp = vtm_get_best_value(s0, s1, s2);
>> +
>> +	if (dtemp < K3_VTM_ADC_BEGIN_VAL || dtemp > K3_VTM_ADC_END_VAL)
>> +		return -EINVAL;
>> +
>> +	*temp = k3_adc_to_temp[dtemp - K3_VTM_ADC_BEGIN_VAL];
> 
> To be sure there is not a subtle memory corruption, I would recommend to
> check the consistency between K3_VTM_ADC_END_VAL - K3_VTM_ADC_BEGIN_VAL
> and the array size at init time.
> 
> For example:
> 
> if (ARRAY_SIZE(k3_adc_to_temp) !=
> 	(K3_VTM_ADC_END_VAL - K3_VTM_ADC_BEGIN_VAL))

okay

> 
>> +	return 0;
>> +}
>> +
>> +static int k3_thermal_get_temp(void *devdata, int *temp)
>> +{
>> +	struct k3_thermal_data *data = devdata;
>> +	int ret = 0;
>> +
>> +	ret = k3_bgp_read_temp(data, temp);
>> +	if (ret)
>> +		return ret;
>> +
>> +	data->prev_temp = *temp;
>> +
>> +	return ret;
>> +}
>> +
>> +static const struct thermal_zone_of_device_ops k3_of_thermal_ops = {
>> +	.get_temp = k3_thermal_get_temp,
>> +};
>> +
>> +static void k3_thermal_work(struct work_struct *work)
>> +{
>> +	struct k3_thermal_data *data = container_of(work,
>> +					struct k3_thermal_data, thermal_wq);
>> +
>> +	thermal_zone_device_update(data->ti_thermal, THERMAL_EVENT_UNSPECIFIED);
>> +
>> +	dev_dbg(&data->ti_thermal->device, "updated thermal zone %s\n",
>> +		data->ti_thermal->type);
>> +}
>> +
>> +static const struct of_device_id of_k3_bandgap_match[];
>> +
>> +static int k3_bandgap_probe(struct platform_device *pdev)
>> +{
>> +	int ret = 0, cnt, val, id, reg_cnt = 0;
>> +	struct resource *res;
>> +	struct device *dev = &pdev->dev;
>> +	struct k3_bandgap *bgp;
>> +	struct k3_thermal_data *data;
>> +
>> +	bgp = devm_kzalloc(&pdev->dev, sizeof(*bgp), GFP_KERNEL);
>> +	if (!bgp)
>> +		return -ENOMEM;
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	bgp->base = devm_ioremap_resource(dev, res);
>> +	if (IS_ERR(bgp->base))
>> +		return PTR_ERR(bgp->base);
>> +
>> +	pm_runtime_enable(dev);
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret < 0) {
>> +		pm_runtime_put_noidle(dev);
>> +		pm_runtime_disable(dev);
>> +		return ret;
>> +	}
>> +
>> +	/* Get the sensor count in the VTM */
>> +	val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
>> +	cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
>> +	cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
>> +
>> +	data = devm_kcalloc(dev, cnt, sizeof(*data), GFP_KERNEL);
>> +	if (!data) {
>> +		ret = -ENOMEM;
>> +		goto err_alloc;
>> +	}
>> +
>> +	/* Register the thermal sensors */
>> +	for (id = 0; id < cnt; id++) {
>> +		data[id].sensor_id = id;
>> +		data[id].bgp = bgp;
>> +		data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET +
>> +					id * K3_VTM_REGS_PER_TS;
>> +		data[id].stat_offset = data[id].ctrl_offset + 0x8;
>> +		INIT_WORK(&data[id].thermal_wq, k3_thermal_work);
> 
> 		What is supposed to do ?

Periodically poll temperature. I know there is no passive cooling agent
like cpufreq at the moment but i do have a critical trip do you 
recommend to remove that?

Thanks,
Keerthy

> 
>> +		val = readl(data[id].bgp->base + data[id].ctrl_offset);
>> +		val |= (K3_VTM_TMPSENS_CTRL_SOC |
>> +			K3_VTM_TMPSENS_CTRL_CLRZ |
>> +			K3_VTM_TMPSENS_CTRL_CLKON_REQ);
>> +		val &= ~K3_VTM_TMPSENS_CTRL_CBIASSEL;
>> +		writel(val, data[id].bgp->base + data[id].ctrl_offset);
>> +
>> +		data[id].ti_thermal =
>> +		devm_thermal_zone_of_sensor_register(dev, id,
>> +						     &data[id],
>> +						     &k3_of_thermal_ops);
>> +		if (IS_ERR(data[id].ti_thermal)) {
>> +			dev_err(dev, "thermal zone device is NULL\n");
>> +			ret = PTR_ERR(data[id].ti_thermal);
>> +			goto err_alloc;
>> +		}
>> +
>> +		reg_cnt++;
>> +
>> +		/* Initialize Previous temp */
>> +		k3_thermal_get_temp(&data[id], &data[id].prev_temp);
>> +	}
>> +
>> +	platform_set_drvdata(pdev, bgp);
>> +
>> +	return 0;
>> +
>> +err_alloc:
>> +	pm_runtime_put_sync(&pdev->dev);
>> +	pm_runtime_disable(&pdev->dev);
>> +
>> +	return ret;
>> +}
>> +
>> +static int k3_bandgap_remove(struct platform_device *pdev)
>> +{
>> +	pm_runtime_put_sync(&pdev->dev);
>> +	pm_runtime_disable(&pdev->dev);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id of_k3_bandgap_match[] = {
>> +	{
>> +		.compatible = "ti,am654-vtm",
>> +	},
>> +	{ /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, of_k3_bandgap_match);
>> +
>> +static struct platform_driver k3_bandgap_sensor_driver = {
>> +	.probe = k3_bandgap_probe,
>> +	.remove = k3_bandgap_remove,
>> +	.driver = {
>> +		.name = "k3-soc-thermal",
>> +		.of_match_table	= of_k3_bandgap_match,
>> +	},
>> +};
>> +
>> +module_platform_driver(k3_bandgap_sensor_driver);
>> +
>> +MODULE_DESCRIPTION("K3 bandgap temperature sensor driver");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR("J Keerthy <j-keerthy@ti.com>");
>>
> 
>
Daniel Lezcano March 19, 2020, 1:36 p.m. UTC | #3
On 19/03/2020 13:52, Keerthy wrote:
> 
> 
> On 19/03/20 6:08 pm, Daniel Lezcano wrote:
>> On 18/03/2020 09:30, Keerthy wrote:
>>> The bandgap provides current and voltage reference for its internal
>>> circuits and other analog IP blocks. The analog-to-digital
>>> converter (ADC) produces an output value that is proportional
>>> to the silicon temperature.
>>>
>>> Currently reading temperatures and creating work to periodically
>>> read temperatures from the zones are supported.
>>> There are no active/passive cooling agent supported.
>>>
>>> Signed-off-by: Keerthy <j-keerthy@ti.com>
>>> ---

[ ... ]

>>> +static const int k3_adc_to_temp[] = {
>>> +    -40000, -40000, -40000, -40000, -39800, -39400, -39000, -38600,

[ ... ]

>>> 123000,
>>> +    123400, 123800, 124200, 124600, 124900, 125000,
>>> +};
>>
>> Can be this array replaced by an initialization array with a formula?
>>
>> Why do we have most of the time a step of 400 then suddenly 500 and 400
>> again? eg. 30600, 31000, 31400, 31900, 32500, 33000, 33400
> 
> This has come from a polynomial equation which i do not want to
> calculate every time we read the temperature. Hence prefer Look up table.

Agree, it makes sense to not calculate every time the temperature is read.

I was suggesting to fill the array at init time with this polynomial
formula instead of hardcoding it.

[ ... ]

>>> +
>>> +    /* Get the sensor count in the VTM */
>>> +    val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
>>> +    cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
>>> +    cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
>>> +
>>> +    data = devm_kcalloc(dev, cnt, sizeof(*data), GFP_KERNEL);
>>> +    if (!data) {
>>> +        ret = -ENOMEM;
>>> +        goto err_alloc;
>>> +    }
>>> +
>>> +    /* Register the thermal sensors */
>>> +    for (id = 0; id < cnt; id++) {
>>> +        data[id].sensor_id = id;
>>> +        data[id].bgp = bgp;
>>> +        data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET +
>>> +                    id * K3_VTM_REGS_PER_TS;
>>> +        data[id].stat_offset = data[id].ctrl_offset + 0x8;
>>> +        INIT_WORK(&data[id].thermal_wq, k3_thermal_work);
>>
>>         What is supposed to do ?
> 
> Periodically poll temperature. I know there is no passive cooling agent
> like cpufreq at the moment but i do have a critical trip do you
> recommend to remove that?

Actually I was referring to the workq which is initialized, the callback
set but it is never called. It can be removed.

Please take also the opportunity to wrap the calls to the register with
an explicit helper function name.

And remove reg_cnt which is unused.

Thanks

  -- Daniel
J, KEERTHY March 23, 2020, 3:52 a.m. UTC | #4
On 3/19/2020 7:06 PM, Daniel Lezcano wrote:
> On 19/03/2020 13:52, Keerthy wrote:
>>
>>
>> On 19/03/20 6:08 pm, Daniel Lezcano wrote:
>>> On 18/03/2020 09:30, Keerthy wrote:
>>>> The bandgap provides current and voltage reference for its internal
>>>> circuits and other analog IP blocks. The analog-to-digital
>>>> converter (ADC) produces an output value that is proportional
>>>> to the silicon temperature.
>>>>
>>>> Currently reading temperatures and creating work to periodically
>>>> read temperatures from the zones are supported.
>>>> There are no active/passive cooling agent supported.
>>>>
>>>> Signed-off-by: Keerthy <j-keerthy@ti.com>
>>>> ---
> 
> [ ... ]
> 
>>>> +static const int k3_adc_to_temp[] = {
>>>> +    -40000, -40000, -40000, -40000, -39800, -39400, -39000, -38600,
> 
> [ ... ]
> 
>>>> 123000,
>>>> +    123400, 123800, 124200, 124600, 124900, 125000,
>>>> +};
>>>
>>> Can be this array replaced by an initialization array with a formula?
>>>
>>> Why do we have most of the time a step of 400 then suddenly 500 and 400
>>> again? eg. 30600, 31000, 31400, 31900, 32500, 33000, 33400
>>
>> This has come from a polynomial equation which i do not want to
>> calculate every time we read the temperature. Hence prefer Look up table.
> 
> Agree, it makes sense to not calculate every time the temperature is read.
> 
> I was suggesting to fill the array at init time with this polynomial
> formula instead of hardcoding it.

As in case of OMAP this is a standard polynomial equation that does not
change so i would prefer not calculating in the driver and having the 
look up table from TRM.

> 
> [ ... ]
> 
>>>> +
>>>> +    /* Get the sensor count in the VTM */
>>>> +    val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
>>>> +    cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
>>>> +    cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
>>>> +
>>>> +    data = devm_kcalloc(dev, cnt, sizeof(*data), GFP_KERNEL);
>>>> +    if (!data) {
>>>> +        ret = -ENOMEM;
>>>> +        goto err_alloc;
>>>> +    }
>>>> +
>>>> +    /* Register the thermal sensors */
>>>> +    for (id = 0; id < cnt; id++) {
>>>> +        data[id].sensor_id = id;
>>>> +        data[id].bgp = bgp;
>>>> +        data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET +
>>>> +                    id * K3_VTM_REGS_PER_TS;
>>>> +        data[id].stat_offset = data[id].ctrl_offset + 0x8;
>>>> +        INIT_WORK(&data[id].thermal_wq, k3_thermal_work);
>>>
>>>          What is supposed to do ?
>>
>> Periodically poll temperature. I know there is no passive cooling agent
>> like cpufreq at the moment but i do have a critical trip do you
>> recommend to remove that?
> 
> Actually I was referring to the workq which is initialized, the callback
> set but it is never called. It can be removed.

Okay got it.

> 
> Please take also the opportunity to wrap the calls to the register with
> an explicit helper function name.

IIUC the comment asks me to define a separate function that takes care 
of the body of the for loop.

> 
> And remove reg_cnt which is unused.

Sure

Thanks,
Keerthy
> 
> Thanks
> 
>    -- Daniel
>

Patch
diff mbox series

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 5a05db5438d6..d848d9a3c4f1 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -251,6 +251,17 @@  config IMX_THERMAL
 	  cpufreq is used as the cooling device to throttle CPUs when the
 	  passive trip is crossed.
 
+config K3_THERMAL
+	tristate "Texas Instruments K3 thermal support"
+	depends on ARCH_K3 || COMPILE_TEST
+	help
+	  If you say yes here you get thermal support for the Texas Instruments
+	  K3 SoC family. The current chip supported is:
+	   - AM654
+
+	  This includes temperature reading functionality and also trend
+	  computation.
+
 config MAX77620_THERMAL
 	tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
 	depends on MFD_MAX77620
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 9fb88e26fb10..5ad6535139ae 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -28,6 +28,7 @@  thermal_sys-$(CONFIG_CLOCK_THERMAL)	+= clock_cooling.o
 # devfreq cooling
 thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
 
+obj-$(CONFIG_K3_THERMAL)	+= k3_bandgap.o
 # platform thermal drivers
 obj-y				+= broadcom/
 obj-$(CONFIG_THERMAL_MMIO)		+= thermal_mmio.o
diff --git a/drivers/thermal/k3_bandgap.c b/drivers/thermal/k3_bandgap.c
new file mode 100644
index 000000000000..d16e60335721
--- /dev/null
+++ b/drivers/thermal/k3_bandgap.c
@@ -0,0 +1,287 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * TI Bandgap temperature sensor driver for K3 SoC Family
+ *
+ * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/pm_runtime.h>
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+#include <linux/workqueue.h>
+#include <linux/thermal.h>
+#include <linux/of.h>
+
+#define K3_VTM_DEVINFO_PWR0_OFFSET		0x4
+#define K3_VTM_DEVINFO_PWR0_CVD_CT_MASK	0xf
+#define K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK	0xf0
+#define K3_VTM_TMPSENS0_CTRL_OFFSET	0x80
+#define K3_VTM_REGS_PER_TS			0x10
+#define K3_VTM_TS_STAT_DTEMP_MASK	0x3ff
+#define K3_VTM_MAX_NUM_TS		8
+#define K3_VTM_TMPSENS_CTRL_CBIASSEL	BIT(0)
+#define K3_VTM_TMPSENS_CTRL_SOC		BIT(5)
+#define K3_VTM_TMPSENS_CTRL_CLRZ		BIT(6)
+#define K3_VTM_TMPSENS_CTRL_CLKON_REQ	BIT(7)
+
+#define K3_VTM_ADC_BEGIN_VAL		540
+#define K3_VTM_ADC_END_VAL		944
+
+static const int k3_adc_to_temp[] = {
+	-40000, -40000, -40000, -40000, -39800, -39400, -39000, -38600, -38200,
+	-37800, -37400, -37000, -36600, -36200, -35800, -35300, -34700, -34200,
+	-33800, -33400, -33000, -32600, -32200, -31800, -31400, -31000, -30600,
+	-30200, -29800, -29400, -29000, -28600, -28200, -27700, -27100, -26600,
+	-26200, -25800, -25400, -25000, -24600, -24200, -23800, -23400, -23000,
+	-22600, -22200, -21800, -21400, -21000, -20500, -19900, -19400, -19000,
+	-18600, -18200, -17800, -17400, -17000, -16600, -16200, -15800, -15400,
+	-15000, -14600, -14200, -13800, -13400, -13000, -12500, -11900, -11400,
+	-11000, -10600, -10200, -9800, -9400, -9000, -8600, -8200, -7800, -7400,
+	-7000, -6600, -6200, -5800, -5400, -5000, -4500, -3900, -3400, -3000,
+	-2600, -2200, -1800, -1400, -1000, -600, -200, 200, 600, 1000, 1400,
+	1800, 2200, 2600, 3000, 3400, 3900, 4500, 5000, 5400, 5800, 6200, 6600,
+	7000, 7400, 7800, 8200, 8600, 9000, 9400, 9800, 10200, 10600, 11000,
+	11400, 11800, 12200, 12700, 13300, 13800, 14200, 14600, 15000, 15400,
+	15800, 16200, 16600, 17000, 17400, 17800, 18200, 18600, 19000, 19400,
+	19800, 20200, 20600, 21000, 21400, 21900, 22500, 23000, 23400, 23800,
+	24200, 24600, 25000, 25400, 25800, 26200, 26600, 27000, 27400, 27800,
+	28200, 28600, 29000, 29400, 29800, 30200, 30600, 31000, 31400, 31900,
+	32500, 33000, 33400, 33800, 34200, 34600, 35000, 35400, 35800, 36200,
+	36600, 37000, 37400, 37800, 38200, 38600, 39000, 39400, 39800, 40200,
+	40600, 41000, 41400, 41800, 42200, 42600, 43100, 43700, 44200, 44600,
+	45000, 45400, 45800, 46200, 46600, 47000, 47400, 47800, 48200, 48600,
+	49000, 49400, 49800, 50200, 50600, 51000, 51400, 51800, 52200, 52600,
+	53000, 53400, 53800, 54200, 54600, 55000, 55400, 55900, 56500, 57000,
+	57400, 57800, 58200, 58600, 59000, 59400, 59800, 60200, 60600, 61000,
+	61400, 61800, 62200, 62600, 63000, 63400, 63800, 64200, 64600, 65000,
+	65400, 65800, 66200, 66600, 67000, 67400, 67800, 68200, 68600, 69000,
+	69400, 69800, 70200, 70600, 71000, 71500, 72100, 72600, 73000, 73400,
+	73800, 74200, 74600, 75000, 75400, 75800, 76200, 76600, 77000, 77400,
+	77800, 78200, 78600, 79000, 79400, 79800, 80200, 80600, 81000, 81400,
+	81800, 82200, 82600, 83000, 83400, 83800, 84200, 84600, 85000, 85400,
+	85800, 86200, 86600, 87000, 87400, 87800, 88200, 88600, 89000, 89400,
+	89800, 90200, 90600, 91000, 91400, 91800, 92200, 92600, 93000, 93400,
+	93800, 94200, 94600, 95000, 95400, 95800, 96200, 96600, 97000, 97500,
+	98100, 98600, 99000, 99400, 99800, 100200, 100600, 101000, 101400,
+	101800, 102200, 102600, 103000, 103400, 103800, 104200, 104600, 105000,
+	105400, 105800, 106200, 106600, 107000, 107400, 107800, 108200, 108600,
+	109000, 109400, 109800, 110200, 110600, 111000, 111400, 111800, 112200,
+	112600, 113000, 113400, 113800, 114200, 114600, 115000, 115400, 115800,
+	116200, 116600, 117000, 117400, 117800, 118200, 118600, 119000, 119400,
+	119800, 120200, 120600, 121000, 121400, 121800, 122200, 122600, 123000,
+	123400, 123800, 124200, 124600, 124900, 125000,
+};
+
+struct k3_thermal_data;
+
+struct k3_bandgap {
+	void __iomem *base;
+	const struct k3_bandgap_data *conf;
+};
+
+/* common data structures */
+struct k3_thermal_data {
+	struct thermal_zone_device *ti_thermal;
+	struct k3_bandgap *bgp;
+	struct work_struct thermal_wq;
+	int sensor_id;
+	u32 ctrl_offset;
+	u32 stat_offset;
+	int prev_temp;
+};
+
+static unsigned int vtm_get_best_value(unsigned int s0, unsigned int s1,
+				       unsigned int s2)
+{
+	int d01 = abs(s0 - s1);
+	int d02 = abs(s0 - s2);
+	int d12 = abs(s1 - s2);
+
+	if (d01 <= d02 && d01 <= d12)
+		return (s0 + s1) / 2;
+
+	if (d02 <= d01 && d02 <= d12)
+		return (s0 + s2) / 2;
+
+	return (s1 + s2) / 2;
+}
+
+static int k3_bgp_read_temp(struct k3_thermal_data *devdata,
+			    int *temp)
+{
+	struct k3_bandgap *bgp;
+	unsigned int dtemp, s0, s1, s2;
+
+	bgp = devdata->bgp;
+
+	/*
+	 * Errata is applicable for am654 pg 1.0 silicon. There
+	 * is a variation of the order for 8-10 degree centigrade.
+	 * Work around that by getting the average of two closest
+	 * readings out of three readings everytime we want to
+	 * report temperatures.
+	 *
+	 * Errata workaround.
+	 */
+	s0 = readl(bgp->base + devdata->stat_offset) &
+		K3_VTM_TS_STAT_DTEMP_MASK;
+	s1 = readl(bgp->base + devdata->stat_offset) &
+		K3_VTM_TS_STAT_DTEMP_MASK;
+	s2 = readl(bgp->base + devdata->stat_offset) &
+		K3_VTM_TS_STAT_DTEMP_MASK;
+	dtemp = vtm_get_best_value(s0, s1, s2);
+
+	if (dtemp < K3_VTM_ADC_BEGIN_VAL || dtemp > K3_VTM_ADC_END_VAL)
+		return -EINVAL;
+
+	*temp = k3_adc_to_temp[dtemp - K3_VTM_ADC_BEGIN_VAL];
+
+	return 0;
+}
+
+static int k3_thermal_get_temp(void *devdata, int *temp)
+{
+	struct k3_thermal_data *data = devdata;
+	int ret = 0;
+
+	ret = k3_bgp_read_temp(data, temp);
+	if (ret)
+		return ret;
+
+	data->prev_temp = *temp;
+
+	return ret;
+}
+
+static const struct thermal_zone_of_device_ops k3_of_thermal_ops = {
+	.get_temp = k3_thermal_get_temp,
+};
+
+static void k3_thermal_work(struct work_struct *work)
+{
+	struct k3_thermal_data *data = container_of(work,
+					struct k3_thermal_data, thermal_wq);
+
+	thermal_zone_device_update(data->ti_thermal, THERMAL_EVENT_UNSPECIFIED);
+
+	dev_dbg(&data->ti_thermal->device, "updated thermal zone %s\n",
+		data->ti_thermal->type);
+}
+
+static const struct of_device_id of_k3_bandgap_match[];
+
+static int k3_bandgap_probe(struct platform_device *pdev)
+{
+	int ret = 0, cnt, val, id, reg_cnt = 0;
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	struct k3_bandgap *bgp;
+	struct k3_thermal_data *data;
+
+	bgp = devm_kzalloc(&pdev->dev, sizeof(*bgp), GFP_KERNEL);
+	if (!bgp)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	bgp->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(bgp->base))
+		return PTR_ERR(bgp->base);
+
+	pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		pm_runtime_disable(dev);
+		return ret;
+	}
+
+	/* Get the sensor count in the VTM */
+	val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
+	cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
+	cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
+
+	data = devm_kcalloc(dev, cnt, sizeof(*data), GFP_KERNEL);
+	if (!data) {
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	/* Register the thermal sensors */
+	for (id = 0; id < cnt; id++) {
+		data[id].sensor_id = id;
+		data[id].bgp = bgp;
+		data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET +
+					id * K3_VTM_REGS_PER_TS;
+		data[id].stat_offset = data[id].ctrl_offset + 0x8;
+		INIT_WORK(&data[id].thermal_wq, k3_thermal_work);
+
+		val = readl(data[id].bgp->base + data[id].ctrl_offset);
+		val |= (K3_VTM_TMPSENS_CTRL_SOC |
+			K3_VTM_TMPSENS_CTRL_CLRZ |
+			K3_VTM_TMPSENS_CTRL_CLKON_REQ);
+		val &= ~K3_VTM_TMPSENS_CTRL_CBIASSEL;
+		writel(val, data[id].bgp->base + data[id].ctrl_offset);
+
+		data[id].ti_thermal =
+		devm_thermal_zone_of_sensor_register(dev, id,
+						     &data[id],
+						     &k3_of_thermal_ops);
+		if (IS_ERR(data[id].ti_thermal)) {
+			dev_err(dev, "thermal zone device is NULL\n");
+			ret = PTR_ERR(data[id].ti_thermal);
+			goto err_alloc;
+		}
+
+		reg_cnt++;
+
+		/* Initialize Previous temp */
+		k3_thermal_get_temp(&data[id], &data[id].prev_temp);
+	}
+
+	platform_set_drvdata(pdev, bgp);
+
+	return 0;
+
+err_alloc:
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static int k3_bandgap_remove(struct platform_device *pdev)
+{
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static const struct of_device_id of_k3_bandgap_match[] = {
+	{
+		.compatible = "ti,am654-vtm",
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, of_k3_bandgap_match);
+
+static struct platform_driver k3_bandgap_sensor_driver = {
+	.probe = k3_bandgap_probe,
+	.remove = k3_bandgap_remove,
+	.driver = {
+		.name = "k3-soc-thermal",
+		.of_match_table	= of_k3_bandgap_match,
+	},
+};
+
+module_platform_driver(k3_bandgap_sensor_driver);
+
+MODULE_DESCRIPTION("K3 bandgap temperature sensor driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("J Keerthy <j-keerthy@ti.com>");