[2/5] iio: adc: break out common code from SPMI VADC

Message ID 20170318133415.22365-1-linus.walleij@linaro.org
State Superseded
Headers show
Series
  • Untitled series #773
Related show

Commit Message

Linus Walleij March 18, 2017, 1:34 p.m.
The SPMI VADC and the earlier XOADC share a subset of
common code, so to be able to use the same code in both
drivers, we break out a separate file with the common code,
prefix exported functions that are no longer static with
qcom_* and bake an object qcom-spmi-vadc.o that contains both
files: qcom-vadc-common.o and qcom-spmi-vadc-core.o.

As we need to follow the procedure for making a kernel module
or compiled in object from several files, but still want to
produce the same module name, rename the qcom-spmi-vadc.c
file to qcom-spmi-vadc-core.c so we can bake the two objects
into qcom-spmi-vadc.o

Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Cc: Ivan T. Ivanov <iivanov.xz@gmail.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Rama Krishna Phani A <rphani@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
ChangeLog v4->v5:
- Fix kernel build again. Give up and create a helper module
  with EXPORT_SYMBOL() functions. It works for allyes and allmod,
  finally. YES I TESTED IT THOROUGHLY:

  x86_64 allmodconfig:
  CC [M]  kernel/configs.o
  CC [M]  drivers/iio/adc/qcom-vadc-common.o
  CC [M]  drivers/iio/adc/qcom-spmi-vadc.o
  CC [M]  drivers/iio/adc/qcom-pm8xxx-xoadc.o
  Building modules, stage 2.
  MODPOST 6247 modules
  CC      drivers/iio/adc/qcom-pm8xxx-xoadc.mod.o
  CC      drivers/iio/adc/qcom-vadc-common.mod.o
  CC      drivers/iio/adc/qcom-spmi-vadc.mod.o
  CC      kernel/configs.mod.o
  LD [M]  drivers/iio/adc/qcom-pm8xxx-xoadc.ko
  LD [M]  drivers/iio/adc/qcom-spmi-vadc.ko
  LD [M]  drivers/iio/adc/qcom-vadc-common.ko
  LD [M]  kernel/configs.ko

  x86_64 allyesconfig:
  CC      drivers/iio/adc/qcom-vadc-common.o
  CC      drivers/iio/adc/qcom-spmi-vadc.o
  CC      drivers/iio/adc/qcom-pm8xxx-xoadc.o
  LD      drivers/iio/adc/built-in.o
  LD      drivers/iio/built-in.o
  LD      vmlinux.o
  MODPOST vmlinux.o
  KSYM    .tmp_kallsyms1.o
  KSYM    .tmp_kallsyms2.o
  LD      vmlinux

  So help me God. And sorry for wasting so much of your time with
  these build issues. :( :( :(

- Missing inclusion guard in the .h file.
ChangeLog v3->v4:
- Fix up the kernel build, tested with allyes and allmod.
ChangeLog v2->v3:
- Rewrite on top of Rama Krishna's changes. Now we use the
  generic channel properties, calibration graph and prescale
  settings in all VADC drivers. I did away with the vtable
  indirection which I just don't see the point of, it's
  better to just pass the type of conversion function around
  and have a switch case select the conversion. It was done like
  that in the vendor tree but it's not a good idea.
ChangeLog v1->v2:
- No changes just reposting
---
 drivers/iio/adc/Kconfig            |   4 +
 drivers/iio/adc/Makefile           |   1 +
 drivers/iio/adc/qcom-spmi-vadc.c   | 325 ++-----------------------------------
 drivers/iio/adc/qcom-vadc-common.c | 230 ++++++++++++++++++++++++++
 drivers/iio/adc/qcom-vadc-common.h | 108 ++++++++++++
 5 files changed, 358 insertions(+), 310 deletions(-)
 create mode 100644 drivers/iio/adc/qcom-vadc-common.c
 create mode 100644 drivers/iio/adc/qcom-vadc-common.h

-- 
2.9.3

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Comments

Jonathan Cameron March 19, 2017, 9:36 a.m. | #1
On 18/03/17 13:34, Linus Walleij wrote:
> The SPMI VADC and the earlier XOADC share a subset of

> common code, so to be able to use the same code in both

> drivers, we break out a separate file with the common code,

> prefix exported functions that are no longer static with

> qcom_* and bake an object qcom-spmi-vadc.o that contains both

> files: qcom-vadc-common.o and qcom-spmi-vadc-core.o.

> 

> As we need to follow the procedure for making a kernel module

> or compiled in object from several files, but still want to

> produce the same module name, rename the qcom-spmi-vadc.c

> file to qcom-spmi-vadc-core.c so we can bake the two objects

> into qcom-spmi-vadc.o

> 

> Cc: linux-arm-kernel@lists.infradead.org

> Cc: linux-arm-msm@vger.kernel.org

> Cc: Ivan T. Ivanov <iivanov.xz@gmail.com>

> Cc: Andy Gross <andy.gross@linaro.org>

> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>

> Cc: Stephen Boyd <sboyd@codeaurora.org>

> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

> Cc: Rama Krishna Phani A <rphani@codeaurora.org>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Looks fine to me (nearly was last time ;)  Will pickup once the
bindings discussion is complete.

Jonathan
> ---

> ChangeLog v4->v5:

> - Fix kernel build again. Give up and create a helper module

>   with EXPORT_SYMBOL() functions. It works for allyes and allmod,

>   finally. YES I TESTED IT THOROUGHLY:

:)
> 

>   x86_64 allmodconfig:

>   CC [M]  kernel/configs.o

>   CC [M]  drivers/iio/adc/qcom-vadc-common.o

>   CC [M]  drivers/iio/adc/qcom-spmi-vadc.o

>   CC [M]  drivers/iio/adc/qcom-pm8xxx-xoadc.o

>   Building modules, stage 2.

>   MODPOST 6247 modules

>   CC      drivers/iio/adc/qcom-pm8xxx-xoadc.mod.o

>   CC      drivers/iio/adc/qcom-vadc-common.mod.o

>   CC      drivers/iio/adc/qcom-spmi-vadc.mod.o

>   CC      kernel/configs.mod.o

>   LD [M]  drivers/iio/adc/qcom-pm8xxx-xoadc.ko

>   LD [M]  drivers/iio/adc/qcom-spmi-vadc.ko

>   LD [M]  drivers/iio/adc/qcom-vadc-common.ko

>   LD [M]  kernel/configs.ko

> 

>   x86_64 allyesconfig:

>   CC      drivers/iio/adc/qcom-vadc-common.o

>   CC      drivers/iio/adc/qcom-spmi-vadc.o

>   CC      drivers/iio/adc/qcom-pm8xxx-xoadc.o

>   LD      drivers/iio/adc/built-in.o

>   LD      drivers/iio/built-in.o

>   LD      vmlinux.o

>   MODPOST vmlinux.o

>   KSYM    .tmp_kallsyms1.o

>   KSYM    .tmp_kallsyms2.o

>   LD      vmlinux

> 

>   So help me God. And sorry for wasting so much of your time with

>   these build issues. :( :( :(

> 

> - Missing inclusion guard in the .h file.

> ChangeLog v3->v4:

> - Fix up the kernel build, tested with allyes and allmod.

> ChangeLog v2->v3:

> - Rewrite on top of Rama Krishna's changes. Now we use the

>   generic channel properties, calibration graph and prescale

>   settings in all VADC drivers. I did away with the vtable

>   indirection which I just don't see the point of, it's

>   better to just pass the type of conversion function around

>   and have a switch case select the conversion. It was done like

>   that in the vendor tree but it's not a good idea.

> ChangeLog v1->v2:

> - No changes just reposting

> ---

>  drivers/iio/adc/Kconfig            |   4 +

>  drivers/iio/adc/Makefile           |   1 +

>  drivers/iio/adc/qcom-spmi-vadc.c   | 325 ++-----------------------------------

>  drivers/iio/adc/qcom-vadc-common.c | 230 ++++++++++++++++++++++++++

>  drivers/iio/adc/qcom-vadc-common.h | 108 ++++++++++++

>  5 files changed, 358 insertions(+), 310 deletions(-)

>  create mode 100644 drivers/iio/adc/qcom-vadc-common.c

>  create mode 100644 drivers/iio/adc/qcom-vadc-common.h

> 

> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig

> index dedae7adbce9..8720e1c706fe 100644

> --- a/drivers/iio/adc/Kconfig

> +++ b/drivers/iio/adc/Kconfig

> @@ -442,6 +442,9 @@ config PALMAS_GPADC

>  	  is used in smartphones and tablets and supports a 16 channel

>  	  general purpose ADC.

>  

> +config QCOM_VADC_COMMON

> +	tristate

> +

>  config QCOM_SPMI_IADC

>  	tristate "Qualcomm SPMI PMIC current ADC"

>  	depends on SPMI

> @@ -460,6 +463,7 @@ config QCOM_SPMI_VADC

>  	tristate "Qualcomm SPMI PMIC voltage ADC"

>  	depends on SPMI

>  	select REGMAP_SPMI

> +	select QCOM_VADC_COMMON

>  	help

>  	  This is the IIO Voltage ADC driver for Qualcomm QPNP VADC Chip.

>  

> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile

> index d0012620cd1c..8c2e294042ae 100644

> --- a/drivers/iio/adc/Makefile

> +++ b/drivers/iio/adc/Makefile

> @@ -43,6 +43,7 @@ obj-$(CONFIG_MXS_LRADC) += mxs-lradc.o

>  obj-$(CONFIG_NAU7802) += nau7802.o

>  obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o

>  obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o

> +obj-$(CONFIG_QCOM_VADC_COMMON) += qcom-vadc-common.o

>  obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o

>  obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o

>  obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o

> diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c

> index 0a19761d656c..9e600bfd1765 100644

> --- a/drivers/iio/adc/qcom-spmi-vadc.c

> +++ b/drivers/iio/adc/qcom-spmi-vadc.c

> @@ -28,6 +28,8 @@

>  

>  #include <dt-bindings/iio/qcom,spmi-vadc.h>

>  

> +#include "qcom-vadc-common.h"

> +

>  /* VADC register and bit definitions */

>  #define VADC_REVISION2				0x1

>  #define VADC_REVISION2_SUPPORTED_VADC		1

> @@ -75,84 +77,10 @@

>  

>  #define VADC_DATA				0x60	/* 16 bits */

>  

> -#define VADC_CONV_TIME_MIN_US			2000

> -#define VADC_CONV_TIME_MAX_US			2100

> -

> -/* Min ADC code represents 0V */

> -#define VADC_MIN_ADC_CODE			0x6000

> -/* Max ADC code represents full-scale range of 1.8V */

> -#define VADC_MAX_ADC_CODE			0xa800

> -

> -#define VADC_ABSOLUTE_RANGE_UV			625000

> -#define VADC_RATIOMETRIC_RANGE			1800

> -

> -#define VADC_DEF_PRESCALING			0 /* 1:1 */

> -#define VADC_DEF_DECIMATION			0 /* 512 */

> -#define VADC_DEF_HW_SETTLE_TIME			0 /* 0 us */

> -#define VADC_DEF_AVG_SAMPLES			0 /* 1 sample */

> -#define VADC_DEF_CALIB_TYPE			VADC_CALIB_ABSOLUTE

> -

> -#define VADC_DECIMATION_MIN			512

> -#define VADC_DECIMATION_MAX			4096

> -

> -#define VADC_HW_SETTLE_DELAY_MAX		10000

> -#define VADC_AVG_SAMPLES_MAX			512

> -

> -#define KELVINMIL_CELSIUSMIL			273150

> -

> -#define PMI_CHG_SCALE_1				-138890

> -#define PMI_CHG_SCALE_2				391750000000LL

> -

>  #define VADC_CHAN_MIN			VADC_USBIN

>  #define VADC_CHAN_MAX			VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM

>  

>  /**

> - * struct vadc_map_pt - Map the graph representation for ADC channel

> - * @x: Represent the ADC digitized code.

> - * @y: Represent the physical data which can be temperature, voltage,

> - *     resistance.

> - */

> -struct vadc_map_pt {

> -	s32 x;

> -	s32 y;

> -};

> -

> -/*

> - * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.

> - * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for

> - * calibration.

> - */

> -enum vadc_calibration {

> -	VADC_CALIB_ABSOLUTE = 0,

> -	VADC_CALIB_RATIOMETRIC

> -};

> -

> -/**

> - * struct vadc_linear_graph - Represent ADC characteristics.

> - * @dy: numerator slope to calculate the gain.

> - * @dx: denominator slope to calculate the gain.

> - * @gnd: A/D word of the ground reference used for the channel.

> - *

> - * Each ADC device has different offset and gain parameters which are

> - * computed to calibrate the device.

> - */

> -struct vadc_linear_graph {

> -	s32 dy;

> -	s32 dx;

> -	s32 gnd;

> -};

> -

> -/**

> - * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.

> - * @num: the inverse numerator of the gain applied to the input channel.

> - * @den: the inverse denominator of the gain applied to the input channel.

> - */

> -struct vadc_prescale_ratio {

> -	u32 num;

> -	u32 den;

> -};

> -

> -/**

>   * struct vadc_channel_prop - VADC channel property.

>   * @channel: channel number, refer to the channel list.

>   * @calibration: calibration type.

> @@ -162,9 +90,8 @@ struct vadc_prescale_ratio {

>   *	start of conversion.

>   * @avg_samples: ability to provide single result from the ADC

>   *	that is an average of multiple measurements.

> - * @scale_fn: Represents the scaling function to convert voltage

> + * @scale_fn_type: Represents the scaling function to convert voltage

>   *	physical units desired by the client for the channel.

> - *	Referenced from enum vadc_scale_fn_type.

>   */

>  struct vadc_channel_prop {

>  	unsigned int channel;

> @@ -173,7 +100,7 @@ struct vadc_channel_prop {

>  	unsigned int prescale;

>  	unsigned int hw_settle_time;

>  	unsigned int avg_samples;

> -	unsigned int scale_fn;

> +	enum vadc_scale_fn_type scale_fn_type;

>  };

>  

>  /**

> @@ -204,35 +131,6 @@ struct vadc_priv {

>  	struct mutex		 lock;

>  };

>  

> -/**

> - * struct vadc_scale_fn - Scaling function prototype

> - * @scale: Function pointer to one of the scaling functions

> - *	which takes the adc properties, channel properties,

> - *	and returns the physical result.

> - */

> -struct vadc_scale_fn {

> -	int (*scale)(struct vadc_priv *, const struct vadc_channel_prop *,

> -		     u16, int *);

> -};

> -

> -/**

> - * enum vadc_scale_fn_type - Scaling function to convert ADC code to

> - *				physical scaled units for the channel.

> - * SCALE_DEFAULT: Default scaling to convert raw adc code to voltage (uV).

> - * SCALE_THERM_100K_PULLUP: Returns temperature in millidegC.

> - *				 Uses a mapping table with 100K pullup.

> - * SCALE_PMIC_THERM: Returns result in milli degree's Centigrade.

> - * SCALE_XOTHERM: Returns XO thermistor voltage in millidegC.

> - * SCALE_PMI_CHG_TEMP: Conversion for PMI CHG temp

> - */

> -enum vadc_scale_fn_type {

> -	SCALE_DEFAULT = 0,

> -	SCALE_THERM_100K_PULLUP,

> -	SCALE_PMIC_THERM,

> -	SCALE_XOTHERM,

> -	SCALE_PMI_CHG_TEMP,

> -};

> -

>  static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {

>  	{.num =  1, .den =  1},

>  	{.num =  1, .den =  3},

> @@ -244,44 +142,6 @@ static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {

>  	{.num =  1, .den = 10}

>  };

>  

> -/* Voltage to temperature */

> -static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {

> -	{1758,	-40},

> -	{1742,	-35},

> -	{1719,	-30},

> -	{1691,	-25},

> -	{1654,	-20},

> -	{1608,	-15},

> -	{1551,	-10},

> -	{1483,	-5},

> -	{1404,	0},

> -	{1315,	5},

> -	{1218,	10},

> -	{1114,	15},

> -	{1007,	20},

> -	{900,	25},

> -	{795,	30},

> -	{696,	35},

> -	{605,	40},

> -	{522,	45},

> -	{448,	50},

> -	{383,	55},

> -	{327,	60},

> -	{278,	65},

> -	{237,	70},

> -	{202,	75},

> -	{172,	80},

> -	{146,	85},

> -	{125,	90},

> -	{107,	95},

> -	{92,	100},

> -	{79,	105},

> -	{68,	110},

> -	{59,	115},

> -	{51,	120},

> -	{44,	125}

> -};

> -

>  static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)

>  {

>  	return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);

> @@ -553,159 +413,6 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc)

>  	return ret;

>  }

>  

> -static int vadc_map_voltage_temp(const struct vadc_map_pt *pts,

> -				 u32 tablesize, s32 input, s64 *output)

> -{

> -	bool descending = 1;

> -	u32 i = 0;

> -

> -	if (!pts)

> -		return -EINVAL;

> -

> -	/* Check if table is descending or ascending */

> -	if (tablesize > 1) {

> -		if (pts[0].x < pts[1].x)

> -			descending = 0;

> -	}

> -

> -	while (i < tablesize) {

> -		if ((descending) && (pts[i].x < input)) {

> -			/* table entry is less than measured*/

> -			 /* value and table is descending, stop */

> -			break;

> -		} else if ((!descending) &&

> -				(pts[i].x > input)) {

> -			/* table entry is greater than measured*/

> -			/*value and table is ascending, stop */

> -			break;

> -		}

> -		i++;

> -	}

> -

> -	if (i == 0) {

> -		*output = pts[0].y;

> -	} else if (i == tablesize) {

> -		*output = pts[tablesize - 1].y;

> -	} else {

> -		/* result is between search_index and search_index-1 */

> -		/* interpolate linearly */

> -		*output = (((s32)((pts[i].y - pts[i - 1].y) *

> -			(input - pts[i - 1].x)) /

> -			(pts[i].x - pts[i - 1].x)) +

> -			pts[i - 1].y);

> -	}

> -

> -	return 0;

> -}

> -

> -static void vadc_scale_calib(struct vadc_priv *vadc, u16 adc_code,

> -			     const struct vadc_channel_prop *prop,

> -			     s64 *scale_voltage)

> -{

> -	*scale_voltage = (adc_code -

> -		vadc->graph[prop->calibration].gnd);

> -	*scale_voltage *= vadc->graph[prop->calibration].dx;

> -	*scale_voltage = div64_s64(*scale_voltage,

> -		vadc->graph[prop->calibration].dy);

> -	if (prop->calibration == VADC_CALIB_ABSOLUTE)

> -		*scale_voltage +=

> -		vadc->graph[prop->calibration].dx;

> -

> -	if (*scale_voltage < 0)

> -		*scale_voltage = 0;

> -}

> -

> -static int vadc_scale_volt(struct vadc_priv *vadc,

> -			   const struct vadc_channel_prop *prop, u16 adc_code,

> -			   int *result_uv)

> -{

> -	const struct vadc_prescale_ratio *prescale;

> -	s64 voltage = 0, result = 0;

> -

> -	vadc_scale_calib(vadc, adc_code, prop, &voltage);

> -

> -	prescale = &vadc_prescale_ratios[prop->prescale];

> -	voltage = voltage * prescale->den;

> -	result = div64_s64(voltage, prescale->num);

> -	*result_uv = result;

> -

> -	return 0;

> -}

> -

> -static int vadc_scale_therm(struct vadc_priv *vadc,

> -			    const struct vadc_channel_prop *prop, u16 adc_code,

> -			    int *result_mdec)

> -{

> -	s64 voltage = 0, result = 0;

> -

> -	vadc_scale_calib(vadc, adc_code, prop, &voltage);

> -

> -	if (prop->calibration == VADC_CALIB_ABSOLUTE)

> -		voltage = div64_s64(voltage, 1000);

> -

> -	vadc_map_voltage_temp(adcmap_100k_104ef_104fb,

> -			      ARRAY_SIZE(adcmap_100k_104ef_104fb),

> -			      voltage, &result);

> -	result *= 1000;

> -	*result_mdec = result;

> -

> -	return 0;

> -}

> -

> -static int vadc_scale_die_temp(struct vadc_priv *vadc,

> -			       const struct vadc_channel_prop *prop,

> -			       u16 adc_code, int *result_mdec)

> -{

> -	const struct vadc_prescale_ratio *prescale;

> -	s64 voltage = 0;

> -	u64 temp; /* Temporary variable for do_div */

> -

> -	vadc_scale_calib(vadc, adc_code, prop, &voltage);

> -

> -	if (voltage > 0) {

> -		prescale = &vadc_prescale_ratios[prop->prescale];

> -		temp = voltage * prescale->den;

> -		do_div(temp, prescale->num * 2);

> -		voltage = temp;

> -	} else {

> -		voltage = 0;

> -	}

> -

> -	voltage -= KELVINMIL_CELSIUSMIL;

> -	*result_mdec = voltage;

> -

> -	return 0;

> -}

> -

> -static int vadc_scale_chg_temp(struct vadc_priv *vadc,

> -			       const struct vadc_channel_prop *prop,

> -			       u16 adc_code, int *result_mdec)

> -{

> -	const struct vadc_prescale_ratio *prescale;

> -	s64 voltage = 0, result = 0;

> -

> -	vadc_scale_calib(vadc, adc_code, prop, &voltage);

> -

> -	prescale = &vadc_prescale_ratios[prop->prescale];

> -	voltage = voltage * prescale->den;

> -	voltage = div64_s64(voltage, prescale->num);

> -	voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));

> -	voltage = (voltage + PMI_CHG_SCALE_2);

> -	result =  div64_s64(voltage, 1000000);

> -	*result_mdec = result;

> -

> -	return 0;

> -}

> -

> -static int vadc_decimation_from_dt(u32 value)

> -{

> -	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||

> -	    value > VADC_DECIMATION_MAX)

> -		return -EINVAL;

> -

> -	return __ffs64(value / VADC_DECIMATION_MIN);

> -}

> -

>  static int vadc_prescaling_from_dt(u32 num, u32 den)

>  {

>  	unsigned int pre;

> @@ -742,14 +449,6 @@ static int vadc_avg_samples_from_dt(u32 value)

>  	return __ffs64(value);

>  }

>  

> -static struct vadc_scale_fn scale_fn[] = {

> -	[SCALE_DEFAULT] = {vadc_scale_volt},

> -	[SCALE_THERM_100K_PULLUP] = {vadc_scale_therm},

> -	[SCALE_PMIC_THERM] = {vadc_scale_die_temp},

> -	[SCALE_XOTHERM] = {vadc_scale_therm},

> -	[SCALE_PMI_CHG_TEMP] = {vadc_scale_chg_temp},

> -};

> -

>  static int vadc_read_raw(struct iio_dev *indio_dev,

>  			 struct iio_chan_spec const *chan, int *val, int *val2,

>  			 long mask)

> @@ -766,7 +465,13 @@ static int vadc_read_raw(struct iio_dev *indio_dev,

>  		if (ret)

>  			break;

>  

> -		scale_fn[prop->scale_fn].scale(vadc, prop, adc_code, val);

> +		ret = qcom_vadc_scale(prop->scale_fn_type,

> +				&vadc->graph[prop->calibration],

> +				&vadc_prescale_ratios[prop->prescale],

> +				(prop->calibration == VADC_CALIB_ABSOLUTE),

> +				adc_code, val);

> +		if (ret)

> +			break;

>  

>  		return IIO_VAL_INT;

>  	case IIO_CHAN_INFO_RAW:

> @@ -809,7 +514,7 @@ struct vadc_channels {

>  	unsigned int prescale_index;

>  	enum iio_chan_type type;

>  	long info_mask;

> -	unsigned int scale_fn;

> +	enum vadc_scale_fn_type scale_fn_type;

>  };

>  

>  #define VADC_CHAN(_dname, _type, _mask, _pre, _scale)			\

> @@ -818,7 +523,7 @@ struct vadc_channels {

>  		.prescale_index = _pre,					\

>  		.type = _type,						\

>  		.info_mask = _mask,					\

> -		.scale_fn = _scale					\

> +		.scale_fn_type = _scale					\

>  	},								\

>  

>  #define VADC_NO_CHAN(_dname, _type, _mask, _pre)			\

> @@ -976,7 +681,7 @@ static int vadc_get_dt_channel_data(struct device *dev,

>  

>  	ret = of_property_read_u32(node, "qcom,decimation", &value);

>  	if (!ret) {

> -		ret = vadc_decimation_from_dt(value);

> +		ret = qcom_vadc_decimation_from_dt(value);

>  		if (ret < 0) {

>  			dev_err(dev, "%02x invalid decimation %d\n",

>  				chan, value);

> @@ -1068,7 +773,7 @@ static int vadc_get_dt_data(struct vadc_priv *vadc, struct device_node *node)

>  			return ret;

>  		}

>  

> -		prop.scale_fn = vadc_chans[prop.channel].scale_fn;

> +		prop.scale_fn_type = vadc_chans[prop.channel].scale_fn_type;

>  		vadc->chan_props[index] = prop;

>  

>  		vadc_chan = &vadc_chans[prop.channel];

> diff --git a/drivers/iio/adc/qcom-vadc-common.c b/drivers/iio/adc/qcom-vadc-common.c

> new file mode 100644

> index 000000000000..102fc51b10aa

> --- /dev/null

> +++ b/drivers/iio/adc/qcom-vadc-common.c

> @@ -0,0 +1,230 @@

> +#include <linux/bug.h>

> +#include <linux/kernel.h>

> +#include <linux/bitops.h>

> +#include <linux/math64.h>

> +#include <linux/log2.h>

> +#include <linux/err.h>

> +

> +#include "qcom-vadc-common.h"

> +

> +/* Voltage to temperature */

> +static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {

> +	{1758,	-40},

> +	{1742,	-35},

> +	{1719,	-30},

> +	{1691,	-25},

> +	{1654,	-20},

> +	{1608,	-15},

> +	{1551,	-10},

> +	{1483,	-5},

> +	{1404,	0},

> +	{1315,	5},

> +	{1218,	10},

> +	{1114,	15},

> +	{1007,	20},

> +	{900,	25},

> +	{795,	30},

> +	{696,	35},

> +	{605,	40},

> +	{522,	45},

> +	{448,	50},

> +	{383,	55},

> +	{327,	60},

> +	{278,	65},

> +	{237,	70},

> +	{202,	75},

> +	{172,	80},

> +	{146,	85},

> +	{125,	90},

> +	{107,	95},

> +	{92,	100},

> +	{79,	105},

> +	{68,	110},

> +	{59,	115},

> +	{51,	120},

> +	{44,	125}

> +};

> +

> +static int qcom_vadc_map_voltage_temp(const struct vadc_map_pt *pts,

> +				      u32 tablesize, s32 input, s64 *output)

> +{

> +	bool descending = 1;

> +	u32 i = 0;

> +

> +	if (!pts)

> +		return -EINVAL;

> +

> +	/* Check if table is descending or ascending */

> +	if (tablesize > 1) {

> +		if (pts[0].x < pts[1].x)

> +			descending = 0;

> +	}

> +

> +	while (i < tablesize) {

> +		if ((descending) && (pts[i].x < input)) {

> +			/* table entry is less than measured*/

> +			 /* value and table is descending, stop */

> +			break;

> +		} else if ((!descending) &&

> +				(pts[i].x > input)) {

> +			/* table entry is greater than measured*/

> +			/*value and table is ascending, stop */

> +			break;

> +		}

> +		i++;

> +	}

> +

> +	if (i == 0) {

> +		*output = pts[0].y;

> +	} else if (i == tablesize) {

> +		*output = pts[tablesize - 1].y;

> +	} else {

> +		/* result is between search_index and search_index-1 */

> +		/* interpolate linearly */

> +		*output = (((s32)((pts[i].y - pts[i - 1].y) *

> +			(input - pts[i - 1].x)) /

> +			(pts[i].x - pts[i - 1].x)) +

> +			pts[i - 1].y);

> +	}

> +

> +	return 0;

> +}

> +

> +static void qcom_vadc_scale_calib(const struct vadc_linear_graph *calib_graph,

> +				  u16 adc_code,

> +				  bool absolute,

> +				  s64 *scale_voltage)

> +{

> +	*scale_voltage = (adc_code - calib_graph->gnd);

> +	*scale_voltage *= calib_graph->dx;

> +	*scale_voltage = div64_s64(*scale_voltage, calib_graph->dy);

> +	if (absolute)

> +		*scale_voltage += calib_graph->dx;

> +

> +	if (*scale_voltage < 0)

> +		*scale_voltage = 0;

> +}

> +

> +static int qcom_vadc_scale_volt(const struct vadc_linear_graph *calib_graph,

> +				const struct vadc_prescale_ratio *prescale,

> +				bool absolute, u16 adc_code,

> +				int *result_uv)

> +{

> +	s64 voltage = 0, result = 0;

> +

> +	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);

> +

> +	voltage = voltage * prescale->den;

> +	result = div64_s64(voltage, prescale->num);

> +	*result_uv = result;

> +

> +	return 0;

> +}

> +

> +static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,

> +				 const struct vadc_prescale_ratio *prescale,

> +				 bool absolute, u16 adc_code,

> +				 int *result_mdec)

> +{

> +	s64 voltage = 0, result = 0;

> +	int ret;

> +

> +	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);

> +

> +	if (absolute)

> +		voltage = div64_s64(voltage, 1000);

> +

> +	ret = qcom_vadc_map_voltage_temp(adcmap_100k_104ef_104fb,

> +					 ARRAY_SIZE(adcmap_100k_104ef_104fb),

> +					 voltage, &result);

> +	if (ret)

> +		return ret;

> +

> +	result *= 1000;

> +	*result_mdec = result;

> +

> +	return 0;

> +}

> +

> +static int qcom_vadc_scale_die_temp(const struct vadc_linear_graph *calib_graph,

> +				    const struct vadc_prescale_ratio *prescale,

> +				    bool absolute,

> +				    u16 adc_code, int *result_mdec)

> +{

> +	s64 voltage = 0;

> +	u64 temp; /* Temporary variable for do_div */

> +

> +	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);

> +

> +	if (voltage > 0) {

> +		temp = voltage * prescale->den;

> +		do_div(temp, prescale->num * 2);

> +		voltage = temp;

> +	} else {

> +		voltage = 0;

> +	}

> +

> +	voltage -= KELVINMIL_CELSIUSMIL;

> +	*result_mdec = voltage;

> +

> +	return 0;

> +}

> +

> +static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,

> +				    const struct vadc_prescale_ratio *prescale,

> +				    bool absolute,

> +				    u16 adc_code, int *result_mdec)

> +{

> +	s64 voltage = 0, result = 0;

> +

> +	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);

> +

> +	voltage = voltage * prescale->den;

> +	voltage = div64_s64(voltage, prescale->num);

> +	voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));

> +	voltage = (voltage + PMI_CHG_SCALE_2);

> +	result =  div64_s64(voltage, 1000000);

> +	*result_mdec = result;

> +

> +	return 0;

> +}

> +

> +int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,

> +		    const struct vadc_linear_graph *calib_graph,

> +		    const struct vadc_prescale_ratio *prescale,

> +		    bool absolute,

> +		    u16 adc_code, int *result)

> +{

> +	switch (scaletype) {

> +	case SCALE_DEFAULT:

> +		return qcom_vadc_scale_volt(calib_graph, prescale,

> +					    absolute, adc_code,

> +					    result);

> +	case SCALE_THERM_100K_PULLUP:

> +	case SCALE_XOTHERM:

> +		return qcom_vadc_scale_therm(calib_graph, prescale,

> +					     absolute, adc_code,

> +					     result);

> +	case SCALE_PMIC_THERM:

> +		return qcom_vadc_scale_die_temp(calib_graph, prescale,

> +						absolute, adc_code,

> +						result);

> +	case SCALE_PMI_CHG_TEMP:

> +		return qcom_vadc_scale_chg_temp(calib_graph, prescale,

> +						absolute, adc_code,

> +						result);

> +	default:

> +		return -EINVAL;

> +	}

> +}

> +EXPORT_SYMBOL(qcom_vadc_scale);

> +

> +int qcom_vadc_decimation_from_dt(u32 value)

> +{

> +	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||

> +	    value > VADC_DECIMATION_MAX)

> +		return -EINVAL;

> +

> +	return __ffs64(value / VADC_DECIMATION_MIN);

> +}

> +EXPORT_SYMBOL(qcom_vadc_decimation_from_dt);

> diff --git a/drivers/iio/adc/qcom-vadc-common.h b/drivers/iio/adc/qcom-vadc-common.h

> new file mode 100644

> index 000000000000..63c872a70adc

> --- /dev/null

> +++ b/drivers/iio/adc/qcom-vadc-common.h

> @@ -0,0 +1,108 @@

> +/*

> + * Code shared between the different Qualcomm PMIC voltage ADCs

> + */

> +

> +#ifndef QCOM_VADC_COMMON_H

> +#define QCOM_VADC_COMMON_H

> +

> +#define VADC_CONV_TIME_MIN_US			2000

> +#define VADC_CONV_TIME_MAX_US			2100

> +

> +/* Min ADC code represents 0V */

> +#define VADC_MIN_ADC_CODE			0x6000

> +/* Max ADC code represents full-scale range of 1.8V */

> +#define VADC_MAX_ADC_CODE			0xa800

> +

> +#define VADC_ABSOLUTE_RANGE_UV			625000

> +#define VADC_RATIOMETRIC_RANGE			1800

> +

> +#define VADC_DEF_PRESCALING			0 /* 1:1 */

> +#define VADC_DEF_DECIMATION			0 /* 512 */

> +#define VADC_DEF_HW_SETTLE_TIME			0 /* 0 us */

> +#define VADC_DEF_AVG_SAMPLES			0 /* 1 sample */

> +#define VADC_DEF_CALIB_TYPE			VADC_CALIB_ABSOLUTE

> +

> +#define VADC_DECIMATION_MIN			512

> +#define VADC_DECIMATION_MAX			4096

> +

> +#define VADC_HW_SETTLE_DELAY_MAX		10000

> +#define VADC_AVG_SAMPLES_MAX			512

> +

> +#define KELVINMIL_CELSIUSMIL			273150

> +

> +#define PMI_CHG_SCALE_1				-138890

> +#define PMI_CHG_SCALE_2				391750000000LL

> +

> +/**

> + * struct vadc_map_pt - Map the graph representation for ADC channel

> + * @x: Represent the ADC digitized code.

> + * @y: Represent the physical data which can be temperature, voltage,

> + *     resistance.

> + */

> +struct vadc_map_pt {

> +	s32 x;

> +	s32 y;

> +};

> +

> +/*

> + * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.

> + * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for

> + * calibration.

> + */

> +enum vadc_calibration {

> +	VADC_CALIB_ABSOLUTE = 0,

> +	VADC_CALIB_RATIOMETRIC

> +};

> +

> +/**

> + * struct vadc_linear_graph - Represent ADC characteristics.

> + * @dy: numerator slope to calculate the gain.

> + * @dx: denominator slope to calculate the gain.

> + * @gnd: A/D word of the ground reference used for the channel.

> + *

> + * Each ADC device has different offset and gain parameters which are

> + * computed to calibrate the device.

> + */

> +struct vadc_linear_graph {

> +	s32 dy;

> +	s32 dx;

> +	s32 gnd;

> +};

> +

> +/**

> + * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.

> + * @num: the inverse numerator of the gain applied to the input channel.

> + * @den: the inverse denominator of the gain applied to the input channel.

> + */

> +struct vadc_prescale_ratio {

> +	u32 num;

> +	u32 den;

> +};

> +

> +/**

> + * enum vadc_scale_fn_type - Scaling function to convert ADC code to

> + *				physical scaled units for the channel.

> + * SCALE_DEFAULT: Default scaling to convert raw adc code to voltage (uV).

> + * SCALE_THERM_100K_PULLUP: Returns temperature in millidegC.

> + *				 Uses a mapping table with 100K pullup.

> + * SCALE_PMIC_THERM: Returns result in milli degree's Centigrade.

> + * SCALE_XOTHERM: Returns XO thermistor voltage in millidegC.

> + * SCALE_PMI_CHG_TEMP: Conversion for PMI CHG temp

> + */

> +enum vadc_scale_fn_type {

> +	SCALE_DEFAULT = 0,

> +	SCALE_THERM_100K_PULLUP,

> +	SCALE_PMIC_THERM,

> +	SCALE_XOTHERM,

> +	SCALE_PMI_CHG_TEMP,

> +};

> +

> +int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,

> +		    const struct vadc_linear_graph *calib_graph,

> +		    const struct vadc_prescale_ratio *prescale,

> +		    bool absolute,

> +		    u16 adc_code, int *result_mdec);

> +

> +int qcom_vadc_decimation_from_dt(u32 value);

> +

> +#endif /* QCOM_VADC_COMMON_H */

> 


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Linus Walleij April 4, 2017, 2:48 p.m. | #2
On Sun, Mar 19, 2017 at 10:36 AM, Jonathan Cameron <jic23@kernel.org> wrote:

> Looks fine to me (nearly was last time ;)  Will pickup once the

> bindings discussion is complete.


Rob ACKed the last incarnation so I've resent the three patches for
IIO in the patch set adding his ACK to the binding patch.

Yours,
Linus Walleij
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Patch hide | download patch | download mbox

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index dedae7adbce9..8720e1c706fe 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -442,6 +442,9 @@  config PALMAS_GPADC
 	  is used in smartphones and tablets and supports a 16 channel
 	  general purpose ADC.
 
+config QCOM_VADC_COMMON
+	tristate
+
 config QCOM_SPMI_IADC
 	tristate "Qualcomm SPMI PMIC current ADC"
 	depends on SPMI
@@ -460,6 +463,7 @@  config QCOM_SPMI_VADC
 	tristate "Qualcomm SPMI PMIC voltage ADC"
 	depends on SPMI
 	select REGMAP_SPMI
+	select QCOM_VADC_COMMON
 	help
 	  This is the IIO Voltage ADC driver for Qualcomm QPNP VADC Chip.
 
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index d0012620cd1c..8c2e294042ae 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -43,6 +43,7 @@  obj-$(CONFIG_MXS_LRADC) += mxs-lradc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
+obj-$(CONFIG_QCOM_VADC_COMMON) += qcom-vadc-common.o
 obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
 obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
index 0a19761d656c..9e600bfd1765 100644
--- a/drivers/iio/adc/qcom-spmi-vadc.c
+++ b/drivers/iio/adc/qcom-spmi-vadc.c
@@ -28,6 +28,8 @@ 
 
 #include <dt-bindings/iio/qcom,spmi-vadc.h>
 
+#include "qcom-vadc-common.h"
+
 /* VADC register and bit definitions */
 #define VADC_REVISION2				0x1
 #define VADC_REVISION2_SUPPORTED_VADC		1
@@ -75,84 +77,10 @@ 
 
 #define VADC_DATA				0x60	/* 16 bits */
 
-#define VADC_CONV_TIME_MIN_US			2000
-#define VADC_CONV_TIME_MAX_US			2100
-
-/* Min ADC code represents 0V */
-#define VADC_MIN_ADC_CODE			0x6000
-/* Max ADC code represents full-scale range of 1.8V */
-#define VADC_MAX_ADC_CODE			0xa800
-
-#define VADC_ABSOLUTE_RANGE_UV			625000
-#define VADC_RATIOMETRIC_RANGE			1800
-
-#define VADC_DEF_PRESCALING			0 /* 1:1 */
-#define VADC_DEF_DECIMATION			0 /* 512 */
-#define VADC_DEF_HW_SETTLE_TIME			0 /* 0 us */
-#define VADC_DEF_AVG_SAMPLES			0 /* 1 sample */
-#define VADC_DEF_CALIB_TYPE			VADC_CALIB_ABSOLUTE
-
-#define VADC_DECIMATION_MIN			512
-#define VADC_DECIMATION_MAX			4096
-
-#define VADC_HW_SETTLE_DELAY_MAX		10000
-#define VADC_AVG_SAMPLES_MAX			512
-
-#define KELVINMIL_CELSIUSMIL			273150
-
-#define PMI_CHG_SCALE_1				-138890
-#define PMI_CHG_SCALE_2				391750000000LL
-
 #define VADC_CHAN_MIN			VADC_USBIN
 #define VADC_CHAN_MAX			VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM
 
 /**
- * struct vadc_map_pt - Map the graph representation for ADC channel
- * @x: Represent the ADC digitized code.
- * @y: Represent the physical data which can be temperature, voltage,
- *     resistance.
- */
-struct vadc_map_pt {
-	s32 x;
-	s32 y;
-};
-
-/*
- * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
- * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for
- * calibration.
- */
-enum vadc_calibration {
-	VADC_CALIB_ABSOLUTE = 0,
-	VADC_CALIB_RATIOMETRIC
-};
-
-/**
- * struct vadc_linear_graph - Represent ADC characteristics.
- * @dy: numerator slope to calculate the gain.
- * @dx: denominator slope to calculate the gain.
- * @gnd: A/D word of the ground reference used for the channel.
- *
- * Each ADC device has different offset and gain parameters which are
- * computed to calibrate the device.
- */
-struct vadc_linear_graph {
-	s32 dy;
-	s32 dx;
-	s32 gnd;
-};
-
-/**
- * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.
- * @num: the inverse numerator of the gain applied to the input channel.
- * @den: the inverse denominator of the gain applied to the input channel.
- */
-struct vadc_prescale_ratio {
-	u32 num;
-	u32 den;
-};
-
-/**
  * struct vadc_channel_prop - VADC channel property.
  * @channel: channel number, refer to the channel list.
  * @calibration: calibration type.
@@ -162,9 +90,8 @@  struct vadc_prescale_ratio {
  *	start of conversion.
  * @avg_samples: ability to provide single result from the ADC
  *	that is an average of multiple measurements.
- * @scale_fn: Represents the scaling function to convert voltage
+ * @scale_fn_type: Represents the scaling function to convert voltage
  *	physical units desired by the client for the channel.
- *	Referenced from enum vadc_scale_fn_type.
  */
 struct vadc_channel_prop {
 	unsigned int channel;
@@ -173,7 +100,7 @@  struct vadc_channel_prop {
 	unsigned int prescale;
 	unsigned int hw_settle_time;
 	unsigned int avg_samples;
-	unsigned int scale_fn;
+	enum vadc_scale_fn_type scale_fn_type;
 };
 
 /**
@@ -204,35 +131,6 @@  struct vadc_priv {
 	struct mutex		 lock;
 };
 
-/**
- * struct vadc_scale_fn - Scaling function prototype
- * @scale: Function pointer to one of the scaling functions
- *	which takes the adc properties, channel properties,
- *	and returns the physical result.
- */
-struct vadc_scale_fn {
-	int (*scale)(struct vadc_priv *, const struct vadc_channel_prop *,
-		     u16, int *);
-};
-
-/**
- * enum vadc_scale_fn_type - Scaling function to convert ADC code to
- *				physical scaled units for the channel.
- * SCALE_DEFAULT: Default scaling to convert raw adc code to voltage (uV).
- * SCALE_THERM_100K_PULLUP: Returns temperature in millidegC.
- *				 Uses a mapping table with 100K pullup.
- * SCALE_PMIC_THERM: Returns result in milli degree's Centigrade.
- * SCALE_XOTHERM: Returns XO thermistor voltage in millidegC.
- * SCALE_PMI_CHG_TEMP: Conversion for PMI CHG temp
- */
-enum vadc_scale_fn_type {
-	SCALE_DEFAULT = 0,
-	SCALE_THERM_100K_PULLUP,
-	SCALE_PMIC_THERM,
-	SCALE_XOTHERM,
-	SCALE_PMI_CHG_TEMP,
-};
-
 static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {
 	{.num =  1, .den =  1},
 	{.num =  1, .den =  3},
@@ -244,44 +142,6 @@  static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {
 	{.num =  1, .den = 10}
 };
 
-/* Voltage to temperature */
-static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {
-	{1758,	-40},
-	{1742,	-35},
-	{1719,	-30},
-	{1691,	-25},
-	{1654,	-20},
-	{1608,	-15},
-	{1551,	-10},
-	{1483,	-5},
-	{1404,	0},
-	{1315,	5},
-	{1218,	10},
-	{1114,	15},
-	{1007,	20},
-	{900,	25},
-	{795,	30},
-	{696,	35},
-	{605,	40},
-	{522,	45},
-	{448,	50},
-	{383,	55},
-	{327,	60},
-	{278,	65},
-	{237,	70},
-	{202,	75},
-	{172,	80},
-	{146,	85},
-	{125,	90},
-	{107,	95},
-	{92,	100},
-	{79,	105},
-	{68,	110},
-	{59,	115},
-	{51,	120},
-	{44,	125}
-};
-
 static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)
 {
 	return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);
@@ -553,159 +413,6 @@  static int vadc_measure_ref_points(struct vadc_priv *vadc)
 	return ret;
 }
 
-static int vadc_map_voltage_temp(const struct vadc_map_pt *pts,
-				 u32 tablesize, s32 input, s64 *output)
-{
-	bool descending = 1;
-	u32 i = 0;
-
-	if (!pts)
-		return -EINVAL;
-
-	/* Check if table is descending or ascending */
-	if (tablesize > 1) {
-		if (pts[0].x < pts[1].x)
-			descending = 0;
-	}
-
-	while (i < tablesize) {
-		if ((descending) && (pts[i].x < input)) {
-			/* table entry is less than measured*/
-			 /* value and table is descending, stop */
-			break;
-		} else if ((!descending) &&
-				(pts[i].x > input)) {
-			/* table entry is greater than measured*/
-			/*value and table is ascending, stop */
-			break;
-		}
-		i++;
-	}
-
-	if (i == 0) {
-		*output = pts[0].y;
-	} else if (i == tablesize) {
-		*output = pts[tablesize - 1].y;
-	} else {
-		/* result is between search_index and search_index-1 */
-		/* interpolate linearly */
-		*output = (((s32)((pts[i].y - pts[i - 1].y) *
-			(input - pts[i - 1].x)) /
-			(pts[i].x - pts[i - 1].x)) +
-			pts[i - 1].y);
-	}
-
-	return 0;
-}
-
-static void vadc_scale_calib(struct vadc_priv *vadc, u16 adc_code,
-			     const struct vadc_channel_prop *prop,
-			     s64 *scale_voltage)
-{
-	*scale_voltage = (adc_code -
-		vadc->graph[prop->calibration].gnd);
-	*scale_voltage *= vadc->graph[prop->calibration].dx;
-	*scale_voltage = div64_s64(*scale_voltage,
-		vadc->graph[prop->calibration].dy);
-	if (prop->calibration == VADC_CALIB_ABSOLUTE)
-		*scale_voltage +=
-		vadc->graph[prop->calibration].dx;
-
-	if (*scale_voltage < 0)
-		*scale_voltage = 0;
-}
-
-static int vadc_scale_volt(struct vadc_priv *vadc,
-			   const struct vadc_channel_prop *prop, u16 adc_code,
-			   int *result_uv)
-{
-	const struct vadc_prescale_ratio *prescale;
-	s64 voltage = 0, result = 0;
-
-	vadc_scale_calib(vadc, adc_code, prop, &voltage);
-
-	prescale = &vadc_prescale_ratios[prop->prescale];
-	voltage = voltage * prescale->den;
-	result = div64_s64(voltage, prescale->num);
-	*result_uv = result;
-
-	return 0;
-}
-
-static int vadc_scale_therm(struct vadc_priv *vadc,
-			    const struct vadc_channel_prop *prop, u16 adc_code,
-			    int *result_mdec)
-{
-	s64 voltage = 0, result = 0;
-
-	vadc_scale_calib(vadc, adc_code, prop, &voltage);
-
-	if (prop->calibration == VADC_CALIB_ABSOLUTE)
-		voltage = div64_s64(voltage, 1000);
-
-	vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
-			      ARRAY_SIZE(adcmap_100k_104ef_104fb),
-			      voltage, &result);
-	result *= 1000;
-	*result_mdec = result;
-
-	return 0;
-}
-
-static int vadc_scale_die_temp(struct vadc_priv *vadc,
-			       const struct vadc_channel_prop *prop,
-			       u16 adc_code, int *result_mdec)
-{
-	const struct vadc_prescale_ratio *prescale;
-	s64 voltage = 0;
-	u64 temp; /* Temporary variable for do_div */
-
-	vadc_scale_calib(vadc, adc_code, prop, &voltage);
-
-	if (voltage > 0) {
-		prescale = &vadc_prescale_ratios[prop->prescale];
-		temp = voltage * prescale->den;
-		do_div(temp, prescale->num * 2);
-		voltage = temp;
-	} else {
-		voltage = 0;
-	}
-
-	voltage -= KELVINMIL_CELSIUSMIL;
-	*result_mdec = voltage;
-
-	return 0;
-}
-
-static int vadc_scale_chg_temp(struct vadc_priv *vadc,
-			       const struct vadc_channel_prop *prop,
-			       u16 adc_code, int *result_mdec)
-{
-	const struct vadc_prescale_ratio *prescale;
-	s64 voltage = 0, result = 0;
-
-	vadc_scale_calib(vadc, adc_code, prop, &voltage);
-
-	prescale = &vadc_prescale_ratios[prop->prescale];
-	voltage = voltage * prescale->den;
-	voltage = div64_s64(voltage, prescale->num);
-	voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));
-	voltage = (voltage + PMI_CHG_SCALE_2);
-	result =  div64_s64(voltage, 1000000);
-	*result_mdec = result;
-
-	return 0;
-}
-
-static int vadc_decimation_from_dt(u32 value)
-{
-	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||
-	    value > VADC_DECIMATION_MAX)
-		return -EINVAL;
-
-	return __ffs64(value / VADC_DECIMATION_MIN);
-}
-
 static int vadc_prescaling_from_dt(u32 num, u32 den)
 {
 	unsigned int pre;
@@ -742,14 +449,6 @@  static int vadc_avg_samples_from_dt(u32 value)
 	return __ffs64(value);
 }
 
-static struct vadc_scale_fn scale_fn[] = {
-	[SCALE_DEFAULT] = {vadc_scale_volt},
-	[SCALE_THERM_100K_PULLUP] = {vadc_scale_therm},
-	[SCALE_PMIC_THERM] = {vadc_scale_die_temp},
-	[SCALE_XOTHERM] = {vadc_scale_therm},
-	[SCALE_PMI_CHG_TEMP] = {vadc_scale_chg_temp},
-};
-
 static int vadc_read_raw(struct iio_dev *indio_dev,
 			 struct iio_chan_spec const *chan, int *val, int *val2,
 			 long mask)
@@ -766,7 +465,13 @@  static int vadc_read_raw(struct iio_dev *indio_dev,
 		if (ret)
 			break;
 
-		scale_fn[prop->scale_fn].scale(vadc, prop, adc_code, val);
+		ret = qcom_vadc_scale(prop->scale_fn_type,
+				&vadc->graph[prop->calibration],
+				&vadc_prescale_ratios[prop->prescale],
+				(prop->calibration == VADC_CALIB_ABSOLUTE),
+				adc_code, val);
+		if (ret)
+			break;
 
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_RAW:
@@ -809,7 +514,7 @@  struct vadc_channels {
 	unsigned int prescale_index;
 	enum iio_chan_type type;
 	long info_mask;
-	unsigned int scale_fn;
+	enum vadc_scale_fn_type scale_fn_type;
 };
 
 #define VADC_CHAN(_dname, _type, _mask, _pre, _scale)			\
@@ -818,7 +523,7 @@  struct vadc_channels {
 		.prescale_index = _pre,					\
 		.type = _type,						\
 		.info_mask = _mask,					\
-		.scale_fn = _scale					\
+		.scale_fn_type = _scale					\
 	},								\
 
 #define VADC_NO_CHAN(_dname, _type, _mask, _pre)			\
@@ -976,7 +681,7 @@  static int vadc_get_dt_channel_data(struct device *dev,
 
 	ret = of_property_read_u32(node, "qcom,decimation", &value);
 	if (!ret) {
-		ret = vadc_decimation_from_dt(value);
+		ret = qcom_vadc_decimation_from_dt(value);
 		if (ret < 0) {
 			dev_err(dev, "%02x invalid decimation %d\n",
 				chan, value);
@@ -1068,7 +773,7 @@  static int vadc_get_dt_data(struct vadc_priv *vadc, struct device_node *node)
 			return ret;
 		}
 
-		prop.scale_fn = vadc_chans[prop.channel].scale_fn;
+		prop.scale_fn_type = vadc_chans[prop.channel].scale_fn_type;
 		vadc->chan_props[index] = prop;
 
 		vadc_chan = &vadc_chans[prop.channel];
diff --git a/drivers/iio/adc/qcom-vadc-common.c b/drivers/iio/adc/qcom-vadc-common.c
new file mode 100644
index 000000000000..102fc51b10aa
--- /dev/null
+++ b/drivers/iio/adc/qcom-vadc-common.c
@@ -0,0 +1,230 @@ 
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/math64.h>
+#include <linux/log2.h>
+#include <linux/err.h>
+
+#include "qcom-vadc-common.h"
+
+/* Voltage to temperature */
+static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {
+	{1758,	-40},
+	{1742,	-35},
+	{1719,	-30},
+	{1691,	-25},
+	{1654,	-20},
+	{1608,	-15},
+	{1551,	-10},
+	{1483,	-5},
+	{1404,	0},
+	{1315,	5},
+	{1218,	10},
+	{1114,	15},
+	{1007,	20},
+	{900,	25},
+	{795,	30},
+	{696,	35},
+	{605,	40},
+	{522,	45},
+	{448,	50},
+	{383,	55},
+	{327,	60},
+	{278,	65},
+	{237,	70},
+	{202,	75},
+	{172,	80},
+	{146,	85},
+	{125,	90},
+	{107,	95},
+	{92,	100},
+	{79,	105},
+	{68,	110},
+	{59,	115},
+	{51,	120},
+	{44,	125}
+};
+
+static int qcom_vadc_map_voltage_temp(const struct vadc_map_pt *pts,
+				      u32 tablesize, s32 input, s64 *output)
+{
+	bool descending = 1;
+	u32 i = 0;
+
+	if (!pts)
+		return -EINVAL;
+
+	/* Check if table is descending or ascending */
+	if (tablesize > 1) {
+		if (pts[0].x < pts[1].x)
+			descending = 0;
+	}
+
+	while (i < tablesize) {
+		if ((descending) && (pts[i].x < input)) {
+			/* table entry is less than measured*/
+			 /* value and table is descending, stop */
+			break;
+		} else if ((!descending) &&
+				(pts[i].x > input)) {
+			/* table entry is greater than measured*/
+			/*value and table is ascending, stop */
+			break;
+		}
+		i++;
+	}
+
+	if (i == 0) {
+		*output = pts[0].y;
+	} else if (i == tablesize) {
+		*output = pts[tablesize - 1].y;
+	} else {
+		/* result is between search_index and search_index-1 */
+		/* interpolate linearly */
+		*output = (((s32)((pts[i].y - pts[i - 1].y) *
+			(input - pts[i - 1].x)) /
+			(pts[i].x - pts[i - 1].x)) +
+			pts[i - 1].y);
+	}
+
+	return 0;
+}
+
+static void qcom_vadc_scale_calib(const struct vadc_linear_graph *calib_graph,
+				  u16 adc_code,
+				  bool absolute,
+				  s64 *scale_voltage)
+{
+	*scale_voltage = (adc_code - calib_graph->gnd);
+	*scale_voltage *= calib_graph->dx;
+	*scale_voltage = div64_s64(*scale_voltage, calib_graph->dy);
+	if (absolute)
+		*scale_voltage += calib_graph->dx;
+
+	if (*scale_voltage < 0)
+		*scale_voltage = 0;
+}
+
+static int qcom_vadc_scale_volt(const struct vadc_linear_graph *calib_graph,
+				const struct vadc_prescale_ratio *prescale,
+				bool absolute, u16 adc_code,
+				int *result_uv)
+{
+	s64 voltage = 0, result = 0;
+
+	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
+
+	voltage = voltage * prescale->den;
+	result = div64_s64(voltage, prescale->num);
+	*result_uv = result;
+
+	return 0;
+}
+
+static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,
+				 const struct vadc_prescale_ratio *prescale,
+				 bool absolute, u16 adc_code,
+				 int *result_mdec)
+{
+	s64 voltage = 0, result = 0;
+	int ret;
+
+	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
+
+	if (absolute)
+		voltage = div64_s64(voltage, 1000);
+
+	ret = qcom_vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
+					 ARRAY_SIZE(adcmap_100k_104ef_104fb),
+					 voltage, &result);
+	if (ret)
+		return ret;
+
+	result *= 1000;
+	*result_mdec = result;
+
+	return 0;
+}
+
+static int qcom_vadc_scale_die_temp(const struct vadc_linear_graph *calib_graph,
+				    const struct vadc_prescale_ratio *prescale,
+				    bool absolute,
+				    u16 adc_code, int *result_mdec)
+{
+	s64 voltage = 0;
+	u64 temp; /* Temporary variable for do_div */
+
+	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
+
+	if (voltage > 0) {
+		temp = voltage * prescale->den;
+		do_div(temp, prescale->num * 2);
+		voltage = temp;
+	} else {
+		voltage = 0;
+	}
+
+	voltage -= KELVINMIL_CELSIUSMIL;
+	*result_mdec = voltage;
+
+	return 0;
+}
+
+static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,
+				    const struct vadc_prescale_ratio *prescale,
+				    bool absolute,
+				    u16 adc_code, int *result_mdec)
+{
+	s64 voltage = 0, result = 0;
+
+	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
+
+	voltage = voltage * prescale->den;
+	voltage = div64_s64(voltage, prescale->num);
+	voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));
+	voltage = (voltage + PMI_CHG_SCALE_2);
+	result =  div64_s64(voltage, 1000000);
+	*result_mdec = result;
+
+	return 0;
+}
+
+int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
+		    const struct vadc_linear_graph *calib_graph,
+		    const struct vadc_prescale_ratio *prescale,
+		    bool absolute,
+		    u16 adc_code, int *result)
+{
+	switch (scaletype) {
+	case SCALE_DEFAULT:
+		return qcom_vadc_scale_volt(calib_graph, prescale,
+					    absolute, adc_code,
+					    result);
+	case SCALE_THERM_100K_PULLUP:
+	case SCALE_XOTHERM:
+		return qcom_vadc_scale_therm(calib_graph, prescale,
+					     absolute, adc_code,
+					     result);
+	case SCALE_PMIC_THERM:
+		return qcom_vadc_scale_die_temp(calib_graph, prescale,
+						absolute, adc_code,
+						result);
+	case SCALE_PMI_CHG_TEMP:
+		return qcom_vadc_scale_chg_temp(calib_graph, prescale,
+						absolute, adc_code,
+						result);
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL(qcom_vadc_scale);
+
+int qcom_vadc_decimation_from_dt(u32 value)
+{
+	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||
+	    value > VADC_DECIMATION_MAX)
+		return -EINVAL;
+
+	return __ffs64(value / VADC_DECIMATION_MIN);
+}
+EXPORT_SYMBOL(qcom_vadc_decimation_from_dt);
diff --git a/drivers/iio/adc/qcom-vadc-common.h b/drivers/iio/adc/qcom-vadc-common.h
new file mode 100644
index 000000000000..63c872a70adc
--- /dev/null
+++ b/drivers/iio/adc/qcom-vadc-common.h
@@ -0,0 +1,108 @@ 
+/*
+ * Code shared between the different Qualcomm PMIC voltage ADCs
+ */
+
+#ifndef QCOM_VADC_COMMON_H
+#define QCOM_VADC_COMMON_H
+
+#define VADC_CONV_TIME_MIN_US			2000
+#define VADC_CONV_TIME_MAX_US			2100
+
+/* Min ADC code represents 0V */
+#define VADC_MIN_ADC_CODE			0x6000
+/* Max ADC code represents full-scale range of 1.8V */
+#define VADC_MAX_ADC_CODE			0xa800
+
+#define VADC_ABSOLUTE_RANGE_UV			625000
+#define VADC_RATIOMETRIC_RANGE			1800
+
+#define VADC_DEF_PRESCALING			0 /* 1:1 */
+#define VADC_DEF_DECIMATION			0 /* 512 */
+#define VADC_DEF_HW_SETTLE_TIME			0 /* 0 us */
+#define VADC_DEF_AVG_SAMPLES			0 /* 1 sample */
+#define VADC_DEF_CALIB_TYPE			VADC_CALIB_ABSOLUTE
+
+#define VADC_DECIMATION_MIN			512
+#define VADC_DECIMATION_MAX			4096
+
+#define VADC_HW_SETTLE_DELAY_MAX		10000
+#define VADC_AVG_SAMPLES_MAX			512
+
+#define KELVINMIL_CELSIUSMIL			273150
+
+#define PMI_CHG_SCALE_1				-138890
+#define PMI_CHG_SCALE_2				391750000000LL
+
+/**
+ * struct vadc_map_pt - Map the graph representation for ADC channel
+ * @x: Represent the ADC digitized code.
+ * @y: Represent the physical data which can be temperature, voltage,
+ *     resistance.
+ */
+struct vadc_map_pt {
+	s32 x;
+	s32 y;
+};
+
+/*
+ * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
+ * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for
+ * calibration.
+ */
+enum vadc_calibration {
+	VADC_CALIB_ABSOLUTE = 0,
+	VADC_CALIB_RATIOMETRIC
+};
+
+/**
+ * struct vadc_linear_graph - Represent ADC characteristics.
+ * @dy: numerator slope to calculate the gain.
+ * @dx: denominator slope to calculate the gain.
+ * @gnd: A/D word of the ground reference used for the channel.
+ *
+ * Each ADC device has different offset and gain parameters which are
+ * computed to calibrate the device.
+ */
+struct vadc_linear_graph {
+	s32 dy;
+	s32 dx;
+	s32 gnd;
+};
+
+/**
+ * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.
+ * @num: the inverse numerator of the gain applied to the input channel.
+ * @den: the inverse denominator of the gain applied to the input channel.
+ */
+struct vadc_prescale_ratio {
+	u32 num;
+	u32 den;
+};
+
+/**
+ * enum vadc_scale_fn_type - Scaling function to convert ADC code to
+ *				physical scaled units for the channel.
+ * SCALE_DEFAULT: Default scaling to convert raw adc code to voltage (uV).
+ * SCALE_THERM_100K_PULLUP: Returns temperature in millidegC.
+ *				 Uses a mapping table with 100K pullup.
+ * SCALE_PMIC_THERM: Returns result in milli degree's Centigrade.
+ * SCALE_XOTHERM: Returns XO thermistor voltage in millidegC.
+ * SCALE_PMI_CHG_TEMP: Conversion for PMI CHG temp
+ */
+enum vadc_scale_fn_type {
+	SCALE_DEFAULT = 0,
+	SCALE_THERM_100K_PULLUP,
+	SCALE_PMIC_THERM,
+	SCALE_XOTHERM,
+	SCALE_PMI_CHG_TEMP,
+};
+
+int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
+		    const struct vadc_linear_graph *calib_graph,
+		    const struct vadc_prescale_ratio *prescale,
+		    bool absolute,
+		    u16 adc_code, int *result_mdec);
+
+int qcom_vadc_decimation_from_dt(u32 value);
+
+#endif /* QCOM_VADC_COMMON_H */