6.10-stable review patch. If anyone has any objections, please let me know.
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From: Christophe JAILLET christophe.jaillet@wanadoo.fr
[ Upstream commit f8b6c1eb76f73ed721facd58d0cfb08513aad34c ]
If iio_read_channel_processed() fails, 'val->intval' is not updated, but it is still *1000 just after. So, in case of error, the *1000 accumulate and 'val->intval' becomes erroneous.
So instead of rescaling the value after the fact, use the dedicated scaling API. This way the result is updated only when needed. In case of error, the previous value is kept, unmodified.
This should also reduce any inaccuracies resulting from the scaling.
Finally, this is also slightly more efficient as it saves a function call and a multiplication.
Fixes: fb24ccfbe1e0 ("power: supply: add Ingenic JZ47xx battery driver.") Signed-off-by: Christophe JAILLET christophe.jaillet@wanadoo.fr Acked-by: Artur Rojek contact@artur-rojek.eu Link: https://lore.kernel.org/r/51e49c18574003db1e20c9299061a5ecd1661a3c.171912178... Signed-off-by: Sebastian Reichel sebastian.reichel@collabora.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/power/supply/ingenic-battery.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/power/supply/ingenic-battery.c b/drivers/power/supply/ingenic-battery.c index 2e7fdfde47ece..0a40f425c2772 100644 --- a/drivers/power/supply/ingenic-battery.c +++ b/drivers/power/supply/ingenic-battery.c @@ -31,8 +31,9 @@ static int ingenic_battery_get_property(struct power_supply *psy,
switch (psp) { case POWER_SUPPLY_PROP_HEALTH: - ret = iio_read_channel_processed(bat->channel, &val->intval); - val->intval *= 1000; + ret = iio_read_channel_processed_scale(bat->channel, + &val->intval, + 1000); if (val->intval < info->voltage_min_design_uv) val->intval = POWER_SUPPLY_HEALTH_DEAD; else if (val->intval > info->voltage_max_design_uv) @@ -41,8 +42,9 @@ static int ingenic_battery_get_property(struct power_supply *psy, val->intval = POWER_SUPPLY_HEALTH_GOOD; return ret; case POWER_SUPPLY_PROP_VOLTAGE_NOW: - ret = iio_read_channel_processed(bat->channel, &val->intval); - val->intval *= 1000; + ret = iio_read_channel_processed_scale(bat->channel, + &val->intval, + 1000); return ret; case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN: val->intval = info->voltage_min_design_uv;