[PATCH 5.4 110/110] power/supply: ingenic-battery: Dont change scale if theres only one

Greg Kroah-Hartman
2020-01-30T18:46:28Z

From: Paul Cercueil <paul@crapouillou.net>

commit 86b9182df8bb12610d4d6feac45a69f3ed57bfd2 upstream.

The ADC in the JZ4740 can work either in high-precision mode with a 2.5V
range, or in low-precision mode with a 7.5V range. The code in place in
this driver will select the proper scale according to the maximum
voltage of the battery.

The JZ4770 however only has one mode, with a 6.6V range. If only one
scale is available, there's no need to change it (and nothing to change
it to), and trying to do so will fail with -EINVAL.

Fixes: fb24ccfbe1e0 ("power: supply: add Ingenic JZ47xx battery driver.")

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Artur Rojek <contact@artur-rojek.eu>
Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/power/supply/ingenic-battery.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

--- a/drivers/power/supply/ingenic-battery.c
+++ b/drivers/power/supply/ingenic-battery.c
@@ -100,10 +100,17 @@ static int ingenic_battery_set_scale(str
return -EINVAL;
}

- return iio_write_channel_attribute(bat->channel,
- scale_raw[best_idx],
- scale_raw[best_idx + 1],
- IIO_CHAN_INFO_SCALE);
+ /* Only set scale if there is more than one (fractional) entry */
+ if (scale_len > 2) {
+ ret = iio_write_channel_attribute(bat->channel,
+ scale_raw[best_idx],
+ scale_raw[best_idx + 1],
+ IIO_CHAN_INFO_SCALE);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
}

static enum power_supply_property ingenic_battery_properties[] = {