Commit bc5d4a24 authored by Linus Walleij's avatar Linus Walleij Committed by Sebastian Reichel
Browse files

power: supply: ab8500_fg: Use VBAT-to-Ri if possible 



Augment the AB8500 fuel gauge to use the VBAT-to-Ri method of
estimating the internal resistance if possible. Else fall back
to using the temperature-to-Ri or just the default Ri.

Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.com>
parent e9e7d165

drivers/power/supply/ab8500_fg.c

+21 −10
Original line number Diff line number Diff line
@@ -877,27 +877,38 @@ static int ab8500_fg_uncomp_volt_to_capacity(struct ab8500_fg *di) 
/**

 * ab8500_fg_battery_resistance() - Returns the battery inner resistance

 * @di:		pointer to the ab8500_fg structure

 * @vbat_uncomp_uv: Uncompensated VBAT voltage

 *

 * Returns battery inner resistance added with the fuel gauge resistor value

 * to get the total resistance in the whole link from gnd to bat+ node

 * in milliohm.

 */

static int ab8500_fg_battery_resistance(struct ab8500_fg *di)

static int ab8500_fg_battery_resistance(struct ab8500_fg *di, int vbat_uncomp_uv)

{

	struct power_supply_battery_info *bi = di->bm->bi;

	int resistance_percent = 0;

	int resistance;



	/*

	 * Determine the resistance at this voltage. First try VBAT-to-Ri else

	 * just infer it from the surrounding temperature, if nothing works just

	 * use the internal resistance.

	 */

	if (power_supply_supports_vbat2ri(bi)) {

		resistance = power_supply_vbat2ri(bi, vbat_uncomp_uv, di->flags.charging);

		/* Convert to milliohm */

		resistance = resistance / 1000;

	} else if (power_supply_supports_temp2ri(bi)) {

		resistance_percent = power_supply_temp2resist_simple(bi->resist_table,

								     bi->resist_table_size,

								     di->bat_temp / 10);

	/*

	 * We get a percentage of factory resistance here so first get

	 * the factory resistance in milliohms then calculate how much

	 * resistance we have at this temperature.

	 */

	resistance = (bi->factory_internal_resistance_uohm / 1000);

		/* Convert to milliohm */

		resistance = bi->factory_internal_resistance_uohm / 1000;

		resistance = resistance * resistance_percent / 100;

	} else {

		/* Last fallback */

		resistance = bi->factory_internal_resistance_uohm / 1000;

	}



	dev_dbg(di->dev, "%s Temp: %d battery internal resistance: %d"

	    " fg resistance %d, total: %d (mOhm)\n",
@@ -955,7 +966,7 @@ static int ab8500_load_comp_fg_bat_voltage(struct ab8500_fg *di, bool always) 
	vbat_uv = vbat_uv / i;



	/* Next we apply voltage compensation from internal resistance */

	rcomp = ab8500_fg_battery_resistance(di);

	rcomp = ab8500_fg_battery_resistance(di, vbat_uv);

	vbat_uv = vbat_uv - (di->inst_curr_ua * rcomp) / 1000;



	/* Always keep this state at latest measurement */