linux/drivers/iio/adc/qcom-vadc-common.c

// SPDX-License-Identifier: GPL-2.0
#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 <linux/module.h>
#include <linux/units.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}
};

/*
 * Voltage to temperature table for 100k pull up for NTCG104EF104 with
 * 1.875V reference.
 */
static const struct vadc_map_pt adcmap_100k_104ef_104fb_1875_vref[] = {
	{ 1831,	-40000 },
	{ 1814,	-35000 },
	{ 1791,	-30000 },
	{ 1761,	-25000 },
	{ 1723,	-20000 },
	{ 1675,	-15000 },
	{ 1616,	-10000 },
	{ 1545,	-5000 },
	{ 1463,	0 },
	{ 1370,	5000 },
	{ 1268,	10000 },
	{ 1160,	15000 },
	{ 1049,	20000 },
	{ 937,	25000 },
	{ 828,	30000 },
	{ 726,	35000 },
	{ 630,	40000 },
	{ 544,	45000 },
	{ 467,	50000 },
	{ 399,	55000 },
	{ 340,	60000 },
	{ 290,	65000 },
	{ 247,	70000 },
	{ 209,	75000 },
	{ 179,	80000 },
	{ 153,	85000 },
	{ 130,	90000 },
	{ 112,	95000 },
	{ 96,	100000 },
	{ 82,	105000 },
	{ 71,	110000 },
	{ 62,	115000 },
	{ 53,	120000 },
	{ 46,	125000 },
};

static int qcom_vadc_scale_hw_calib_volt(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_uv);
static int qcom_vadc_scale_hw_calib_therm(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec);
static int qcom_vadc_scale_hw_smb_temp(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec);
static int qcom_vadc_scale_hw_chg5_temp(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec);
static int qcom_vadc_scale_hw_calib_die_temp(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec);

static struct qcom_adc5_scale_type scale_adc5_fn[] = {
	[SCALE_HW_CALIB_DEFAULT] = {qcom_vadc_scale_hw_calib_volt},
	[SCALE_HW_CALIB_THERM_100K_PULLUP] = {qcom_vadc_scale_hw_calib_therm},
	[SCALE_HW_CALIB_XOTHERM] = {qcom_vadc_scale_hw_calib_therm},
	[SCALE_HW_CALIB_PMIC_THERM] = {qcom_vadc_scale_hw_calib_die_temp},
	[SCALE_HW_CALIB_PM5_CHG_TEMP] = {qcom_vadc_scale_hw_chg5_temp},
	[SCALE_HW_CALIB_PM5_SMB_TEMP] = {qcom_vadc_scale_hw_smb_temp},
};

static int qcom_vadc_map_voltage_temp(const struct vadc_map_pt *pts,
				      u32 tablesize, s32 input, int *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;
	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_mdec);
	if (ret)
		return ret;

	*result_mdec *= 1000;

	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;
	}

	*result_mdec = milli_kelvin_to_millicelsius(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;
}

static int qcom_vadc_scale_code_voltage_factor(u16 adc_code,
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				unsigned int factor)
{
	s64 voltage, temp, adc_vdd_ref_mv = 1875;

	/*
	 * The normal data range is between 0V to 1.875V. On cases where
	 * we read low voltage values, the ADC code can go beyond the
	 * range and the scale result is incorrect so we clamp the values
	 * for the cases where the code represents a value below 0V
	 */
	if (adc_code > VADC5_MAX_CODE)
		adc_code = 0;

	/* (ADC code * vref_vadc (1.875V)) / full_scale_code */
	voltage = (s64) adc_code * adc_vdd_ref_mv * 1000;
	voltage = div64_s64(voltage, data->full_scale_code_volt);
	if (voltage > 0) {
		voltage *= prescale->den;
		temp = prescale->num * factor;
		voltage = div64_s64(voltage, temp);
	} else {
		voltage = 0;
	}

	return (int) voltage;
}

static int qcom_vadc_scale_hw_calib_volt(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_uv)
{
	*result_uv = qcom_vadc_scale_code_voltage_factor(adc_code,
				prescale, data, 1);

	return 0;
}

static int qcom_vadc_scale_hw_calib_therm(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec)
{
	int voltage;

	voltage = qcom_vadc_scale_code_voltage_factor(adc_code,
				prescale, data, 1000);

	/* Map voltage to temperature from look-up table */
	return qcom_vadc_map_voltage_temp(adcmap_100k_104ef_104fb_1875_vref,
				 ARRAY_SIZE(adcmap_100k_104ef_104fb_1875_vref),
				 voltage, result_mdec);
}

static int qcom_vadc_scale_hw_calib_die_temp(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec)
{
	*result_mdec = qcom_vadc_scale_code_voltage_factor(adc_code,
				prescale, data, 2);
	*result_mdec = milli_kelvin_to_millicelsius(*result_mdec);

	return 0;
}

static int qcom_vadc_scale_hw_smb_temp(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec)
{
	*result_mdec = qcom_vadc_scale_code_voltage_factor(adc_code * 100,
				prescale, data, PMIC5_SMB_TEMP_SCALE_FACTOR);
	*result_mdec = PMIC5_SMB_TEMP_CONSTANT - *result_mdec;

	return 0;
}

static int qcom_vadc_scale_hw_chg5_temp(
				const struct vadc_prescale_ratio *prescale,
				const struct adc5_data *data,
				u16 adc_code, int *result_mdec)
{
	*result_mdec = qcom_vadc_scale_code_voltage_factor(adc_code,
				prescale, data, 4);
	*result_mdec = PMIC5_CHG_TEMP_SCALE_FACTOR - *result_mdec;

	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_adc5_hw_scale(enum vadc_scale_fn_type scaletype,
		    const struct vadc_prescale_ratio *prescale,
		    const struct adc5_data *data,
		    u16 adc_code, int *result)
{
	if (!(scaletype >= SCALE_HW_CALIB_DEFAULT &&
		scaletype < SCALE_HW_CALIB_INVALID)) {
		pr_err("Invalid scale type %d\n", scaletype);
		return -EINVAL;
	}

	return scale_adc5_fn[scaletype].scale_fn(prescale, data,
					adc_code, result);
}
EXPORT_SYMBOL(qcom_adc5_hw_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);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Qualcomm ADC common functionality");