power: supply: ingenic: Fix some error handling paths in ingenic_battery_get_property()

[ 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.1719121781.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/power/supply/ingenic-battery.c b/drivers/power/supply/ingenic-battery.c
index 2e7fdfde47ece1cdd9de98b64572f99120a98ce8..0a40f425c27723ccec49985b8b5e14a737b6a7eb 100644 (file)
--- 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;