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power: supply: bq27xxx: Retrieve again when busy

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[ Upstream commit f16d9fb6cf03fdbdefa41a8b32ba1e57afb7ae3d ]

Multiple applications may access the battery gauge at the same time, so
the gauge may be busy and EBUSY will be returned. The driver will set a
flag to record the EBUSY state, and this flag will be kept until the next
periodic update. When this flag is set, bq27xxx_battery_get_property()
will just return ENODEV until the flag is updated.

Even if the gauge was busy during the last accessing attempt, returning
ENODEV is not ideal, and can cause confusion in the applications layer.

Instead, retry accessing the I2C to update the flag is as expected, for
the gauge typically recovers from busy state within a few milliseconds.
If still failed to access the gauge, the real error code would be returned
instead of ENODEV (as suggested by Pali Rohár).

Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Jerry Lv <Jerry.Lv@axis.com>
Link: https://lore.kernel.org/r/20250415-foo-fix-v2-1-5b45a395e4cc@axis.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jerry Lv
2025-04-15 11:40:47 +08:00
committed by Greg Kroah-Hartman
parent 1fee4324b5
commit 558ba4afdf
2 changed files with 13 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/power/supply/bq27xxx_battery.c
View File

@@ -2044,7 +2044,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
mutex_unlock(&di->lock);
if (psp != POWER_SUPPLY_PROP_PRESENT && di->cache.flags < 0)
return -ENODEV;
return di->cache.flags;
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:

13
drivers/power/supply/bq27xxx_battery_i2c.c
View File

@@ -6,6 +6,7 @@
* Andrew F. Davis <afd@ti.com>
*/
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/module.h>
@@ -32,6 +33,7 @@ static int bq27xxx_battery_i2c_read(struct bq27xxx_device_info *di, u8 reg,
struct i2c_msg msg[2];
u8 data[2];
int ret;
int retry = 0;
if (!client->adapter)
return -ENODEV;
@@ -48,7 +50,16 @@ static int bq27xxx_battery_i2c_read(struct bq27xxx_device_info *di, u8 reg,
else
msg[1].len = 2;
ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
do {
ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
if (ret == -EBUSY && ++retry < 3) {
/* sleep 10 milliseconds when busy */
usleep_range(10000, 11000);
continue;
}
break;
} while (1);
if (ret < 0)
return ret;