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Commit e932d4f0 authored by Linus Walleij's avatar Linus Walleij Committed by Jonathan Cameron
Browse files

iio: adc: break out common code from SPMI VADC



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: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 96b3c833
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+4 −0
Original line number Diff line number Diff line
@@ -496,6 +496,9 @@ 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
@@ -514,6 +517,7 @@ 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.

+1 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ 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
+15 −310
Original line number Diff line number Diff line
@@ -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
@@ -75,83 +77,9 @@

#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.
@@ -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];
+230 −0
Original line number Diff line number Diff line
#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);
+108 −0
Original line number Diff line number Diff line
/*
 * 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 */