Re: [PATCH v2] power/supply: ingenic-battery: Don't change scale if there's only one

From: Artur Rojek
Date: Fri Nov 15 2019 - 12:39:44 EST


Hi Paul.
Comments inline.

On 2019-11-14 17:35, Paul Cercueil wrote:
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@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---

Notes:
v2: Rebased on v5.4-rc7

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

diff --git a/drivers/power/supply/ingenic-battery.c
b/drivers/power/supply/ingenic-battery.c
index 35816d4b3012..5a53057b4f64 100644
--- a/drivers/power/supply/ingenic-battery.c
+++ b/drivers/power/supply/ingenic-battery.c
@@ -80,6 +80,10 @@ static int ingenic_battery_set_scale(struct
ingenic_battery *bat)
if (ret != IIO_AVAIL_LIST || scale_type != IIO_VAL_FRACTIONAL_LOG2)
return -EINVAL;

+ /* Only one (fractional) entry - nothing to change */
+ if (scale_len == 2)
+ return 0;
+

This function also serves to validate that the maximum voltage is in range of available scales.
Please move your code down a bit so that the check for max_mV is still being done.

Thanks,
Artur

max_mV = bat->info.voltage_max_design_uv / 1000;

for (i = 0; i < scale_len; i += 2) {