Commit 2b0e7ac0 authored by Linus Walleij's avatar Linus Walleij Committed by Sebastian Reichel
Browse files

power: supply: ab8500: Integrate thermal zone 



Instead of providing our own homebrewn thermal measurement
code for an NTC and passing tables, we put the NTC thermistor
into the device tree, create a passive thermal zone, and poll
this thermal zone for the temperature.

Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.com>
parent d662a7df

drivers/power/supply/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -728,6 +728,8 @@ config BATTERY_GAUGE_LTC2941 
config AB8500_BM

	bool "AB8500 Battery Management Driver"

	depends on AB8500_CORE && AB8500_GPADC && (IIO = y) && OF

	select THERMAL

	select THERMAL_OF

	help

	  Say Y to include support for AB8500 battery management.

drivers/power/supply/ab8500-bm.h

+0 −33
Original line number Diff line number Diff line
@@ -260,18 +260,6 @@ enum bup_vch_sel { 
#define BUS_PP_PRECHG_CURRENT_MASK		0x0E

#define BUS_POWER_PATH_PRECHG_ENA		0x01



/**

 * struct ab8500_res_to_temp - defines one point in a temp to res curve. To

 * be used in battery packs that combines the identification resistor with a

 * NTC resistor.

 * @temp:			battery pack temperature in Celsius

 * @resist:			NTC resistor net total resistance

 */

struct ab8500_res_to_temp {

	int temp;

	int resist;

};



/* Forward declaration */

struct ab8500_fg;
@@ -351,8 +339,6 @@ struct ab8500_maxim_parameters { 
 * @maint_b_chg_timer_h:	charge time in maintenance B state

 * @low_high_cur_lvl:		charger current in temp low/high state in mA

 * @low_high_vol_lvl:		charger voltage in temp low/high state in mV'

 * @n_r_t_tbl_elements:		number of elements in r_to_t_tbl

 * @r_to_t_tbl:			table containing resistance to temp points

 */

struct ab8500_battery_type {

	int resis_high;
@@ -365,8 +351,6 @@ struct ab8500_battery_type { 
	int maint_b_chg_timer_h;

	int low_high_cur_lvl;

	int low_high_vol_lvl;

	int n_temp_tbl_elements;

	const struct ab8500_res_to_temp *r_to_t_tbl;

};



/**
@@ -449,23 +433,6 @@ struct ab8500_bm_data { 
	const struct ab8500_fg_parameters *fg_params;

};



enum {

	NTC_EXTERNAL = 0,

	NTC_INTERNAL,

};



/**

 * struct res_to_temp - defines one point in a temp to res curve. To

 * be used in battery packs that combines the identification resistor with a

 * NTC resistor.

 * @temp:			battery pack temperature in Celsius

 * @resist:			NTC resistor net total resistance

 */

struct res_to_temp {

	int temp;

	int resist;

};



/* Forward declaration */

struct ab8500_fg;

drivers/power/supply/ab8500_bmdata.c

+0 −24
Original line number Diff line number Diff line
@@ -43,28 +43,6 @@ static struct power_supply_battery_ocv_table ocv_cap_tbl[] = { 
	{ .ocv = 3094000, .capacity = 0},

};



/*

 * Note that the res_to_temp table must be strictly sorted by falling

 * resistance values to work.

 */

static const struct ab8500_res_to_temp temp_tbl[] = {

	{-5, 214834},

	{ 0, 162943},

	{ 5, 124820},

	{10,  96520},

	{15,  75306},

	{20,  59254},

	{25,  47000},

	{30,  37566},

	{35,  30245},

	{40,  24520},

	{45,  20010},

	{50,  16432},

	{55,  13576},

	{60,  11280},

	{65,   9425},

};



/*

 * Note that the batres_vs_temp table must be strictly sorted by falling

 * temperature values to work. Factory resistance is 300 mOhm and the
@@ -92,8 +70,6 @@ static struct ab8500_battery_type bat_type_thermistor_unknown = { 
	.maint_b_chg_timer_h = 200,

	.low_high_cur_lvl = 300,

	.low_high_vol_lvl = 4000,

	.n_temp_tbl_elements = ARRAY_SIZE(temp_tbl),

	.r_to_t_tbl = temp_tbl,

};



static const struct ab8500_bm_capacity_levels cap_levels = {

drivers/power/supply/ab8500_btemp.c

+22 −81
Original line number Diff line number Diff line
@@ -26,13 +26,12 @@ 
#include <linux/mfd/core.h>

#include <linux/mfd/abx500.h>

#include <linux/mfd/abx500/ab8500.h>

#include <linux/thermal.h>

#include <linux/iio/consumer.h>

#include <linux/fixp-arith.h>



#include "ab8500-bm.h"



#define VTVOUT_V			1800



#define BTEMP_THERMAL_LOW_LIMIT		-10

#define BTEMP_THERMAL_MED_LIMIT		0

#define BTEMP_THERMAL_HIGH_LIMIT_52	52
@@ -82,7 +81,7 @@ struct ab8500_btemp_ranges { 
 * @bat_temp:		Dispatched battery temperature in degree Celsius

 * @prev_bat_temp	Last measured battery temperature in degree Celsius

 * @parent:		Pointer to the struct ab8500

 * @adc_btemp_ball:	ADC channel for the battery ball temperature

 * @tz:			Thermal zone for the battery

 * @adc_bat_ctrl:	ADC channel for the battery control

 * @fg:			Pointer to the struct fg

 * @bm:           	Platform specific battery management information
@@ -100,7 +99,7 @@ struct ab8500_btemp { 
	int bat_temp;

	int prev_bat_temp;

	struct ab8500 *parent;

	struct iio_channel *btemp_ball;

	struct thermal_zone_device *tz;

	struct iio_channel *bat_ctrl;

	struct ab8500_fg *fg;

	struct ab8500_bm_data *bm;
@@ -228,76 +227,6 @@ static int ab8500_btemp_get_batctrl_res(struct ab8500_btemp *di) 
	return res;

}



/**

 * ab8500_btemp_res_to_temp() - resistance to temperature

 * @di:		pointer to the ab8500_btemp structure

 * @tbl:	pointer to the resiatance to temperature table

 * @tbl_size:	size of the resistance to temperature table

 * @res:	resistance to calculate the temperature from

 *

 * This function returns the battery temperature in degrees Celsius

 * based on the NTC resistance.

 */

static int ab8500_btemp_res_to_temp(struct ab8500_btemp *di,

	const struct ab8500_res_to_temp *tbl, int tbl_size, int res)

{

	int i;

	/*

	 * Calculate the formula for the straight line

	 * Simple interpolation if we are within

	 * the resistance table limits, extrapolate

	 * if resistance is outside the limits.

	 */

	if (res > tbl[0].resist)

		i = 0;

	else if (res <= tbl[tbl_size - 1].resist)

		i = tbl_size - 2;

	else {

		i = 0;

		while (!(res <= tbl[i].resist &&

			res > tbl[i + 1].resist))

			i++;

	}



	return fixp_linear_interpolate(tbl[i].resist, tbl[i].temp,

				       tbl[i + 1].resist, tbl[i + 1].temp,

				       res);

}



/**

 * ab8500_btemp_measure_temp() - measure battery temperature

 * @di:		pointer to the ab8500_btemp structure

 *

 * Returns battery temperature (on success) else the previous temperature

 */

static int ab8500_btemp_measure_temp(struct ab8500_btemp *di)

{

	int temp, ret;

	static int prev;

	int rntc, vntc;



	ret = iio_read_channel_processed(di->btemp_ball, &vntc);

	if (ret < 0) {

		dev_err(di->dev,

			"%s ADC conversion failed,"

			" using previous value\n", __func__);

		return prev;

	}

	/*

	 * The PCB NTC is sourced from VTVOUT via a 230kOhm

	 * resistor.

	 */

	rntc = 230000 * vntc / (VTVOUT_V - vntc);



	temp = ab8500_btemp_res_to_temp(di,

		di->bm->bat_type->r_to_t_tbl,

		di->bm->bat_type->n_temp_tbl_elements, rntc);

	prev = temp;



	dev_dbg(di->dev, "Battery temperature is %d\n", temp);

	return temp;

}



/**

 * ab8500_btemp_id() - Identify the connected battery

 * @di:		pointer to the ab8500_btemp structure
@@ -347,6 +276,9 @@ static void ab8500_btemp_periodic_work(struct work_struct *work) 
	int bat_temp;

	struct ab8500_btemp *di = container_of(work,

		struct ab8500_btemp, btemp_periodic_work.work);

	/* Assume 25 degrees celsius as start temperature */

	static int prev = 25;

	int ret;



	if (!di->initialized) {

		/* Identify the battery */
@@ -354,7 +286,17 @@ static void ab8500_btemp_periodic_work(struct work_struct *work) 
			dev_warn(di->dev, "failed to identify the battery\n");

	}



	bat_temp = ab8500_btemp_measure_temp(di);

	/* Failover if a reading is erroneous, use last meausurement */

	ret = thermal_zone_get_temp(di->tz, &bat_temp);

	if (ret) {

		dev_err(di->dev, "error reading temperature\n");

		bat_temp = prev;

	} else {

		/* Convert from millicentigrades to centigrades */

		bat_temp /= 1000;

		prev = bat_temp;

	}



	/*

	 * Filter battery temperature.

	 * Allow direct updates on temperature only if two samples result in
@@ -783,12 +725,11 @@ static int ab8500_btemp_probe(struct platform_device *pdev) 
	di->dev = dev;

	di->parent = dev_get_drvdata(pdev->dev.parent);



	/* Get ADC channels */

	di->btemp_ball = devm_iio_channel_get(dev, "btemp_ball");

	if (IS_ERR(di->btemp_ball)) {

		ret = dev_err_probe(dev, PTR_ERR(di->btemp_ball),

				    "failed to get BTEMP BALL ADC channel\n");

		return ret;

	/* Get thermal zone and ADC */

	di->tz = thermal_zone_get_zone_by_name("battery-thermal");

	if (IS_ERR(di->tz)) {

		return dev_err_probe(dev, PTR_ERR(di->tz),

				     "failed to get battery thermal zone\n");

	}

	di->bat_ctrl = devm_iio_channel_get(dev, "bat_ctrl");

	if (IS_ERR(di->bat_ctrl)) {