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power: supply: sbs-battery: Prevent CAPACITY_MODE races 

A subset of smart battery commands return charge or energy depending on
the CAPACITY_MODE bit setting of BatteryMode(). In order to
unambiguously read a charge or energy value, it is necessary to ensure
that CAPACITY_MODE is set as desired, and not changed for the duration
of the attribute read.

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
This commit is contained in:
Shawn Nematbakhsh 2017-06-13 10:53:25 -07:00 committed by Sebastian Reichel
parent 48f680c0a9
commit fe8a653439
1 changed files with 8 additions and 0 deletions
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8
drivers/power/supply/sbs-battery.c
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@ -171,6 +171,7 @@ struct sbs_info {
u32 i2c_retry_count;
u32 poll_retry_count;
struct delayed_work work;
struct mutex mode_lock;
};
static char model_name[I2C_SMBUS_BLOCK_MAX + 1];
@ -622,7 +623,13 @@ static int sbs_get_property(struct power_supply *psy,
if (ret < 0)
break;
/* sbs_get_battery_capacity() will change the battery mode
* temporarily to read the requested attribute. Ensure we stay
* in the desired mode for the duration of the attribute read.
*/
mutex_lock(&chip->mode_lock);
ret = sbs_get_battery_capacity(client, ret, psp, val);
mutex_unlock(&chip->mode_lock);
break;
case POWER_SUPPLY_PROP_SERIAL_NUMBER:
@ -807,6 +814,7 @@ static int sbs_probe(struct i2c_client *client,
psy_cfg.of_node = client->dev.of_node;
psy_cfg.drv_data = chip;
chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
mutex_init(&chip->mode_lock);
/* use pdata if available, fall back to DT properties,
* or hardcoded defaults if not