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power: supply: ab8500_fg: Safeguard compensated voltage 

In some cases when the platform is dissapating more than
500mA the voltage measurements and compensation will become
instable. Add a parameter to bail out of the voltage
measurement if this happens.

This code was found in a Samsung vendor tree.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
This commit is contained in:
Linus Walleij 2022-01-29 01:49:20 +01:00 committed by Sebastian Reichel
parent 673b50322b
commit 965a990427
1 changed files with 13 additions and 2 deletions
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15
drivers/power/supply/ab8500_fg.c
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@ -46,6 +46,8 @@
#define NBR_AVG_SAMPLES 20
#define WAIT_FOR_INST_CURRENT_MAX 70
/* Currents higher than -500mA (dissipating) will make compensation unstable */
#define IGNORE_VBAT_HIGHCUR -500000
#define LOW_BAT_CHECK_INTERVAL (HZ / 16) /* 62.5 ms */
@ -911,12 +913,13 @@ static int ab8500_fg_battery_resistance(struct ab8500_fg *di)
/**
* ab8500_load_comp_fg_bat_voltage() - get load compensated battery voltage
* @di: pointer to the ab8500_fg structure
* @always: always return a voltage, also uncompensated
*
* Returns compensated battery voltage (on success) else error code.
* If always is specified, we always return a voltage but it may be
* uncompensated.
*/
static int ab8500_load_comp_fg_bat_voltage(struct ab8500_fg *di)
static int ab8500_load_comp_fg_bat_voltage(struct ab8500_fg *di, bool always)
{
int i = 0;
int vbat_uv = 0;
@ -941,6 +944,14 @@ static int ab8500_load_comp_fg_bat_voltage(struct ab8500_fg *di)
ab8500_fg_inst_curr_finalize(di, &di->inst_curr_ua);
/*
* If there is too high current dissipation, the compensation cannot be
* trusted so return an error unless we must return something here, as
* enforced by the "always" parameter.
*/
if (!always && di->inst_curr_ua < IGNORE_VBAT_HIGHCUR)
return -EINVAL;
vbat_uv = vbat_uv / i;
/* Next we apply voltage compensation from internal resistance */
@ -964,7 +975,7 @@ static int ab8500_fg_load_comp_volt_to_capacity(struct ab8500_fg *di)
{
int vbat_comp_uv;
vbat_comp_uv = ab8500_load_comp_fg_bat_voltage(di);
vbat_comp_uv = ab8500_load_comp_fg_bat_voltage(di, true);
return ab8500_fg_volt_to_capacity(di, vbat_comp_uv);
}