[PATCH AUTOSEL 4.9 09/66] power: supply: twl4030_charger: fix charging current out-of-bounds

Sasha Levin
2019-11-10T02:49:16Z

From: Andreas Kemnade <andreas@kemnade.info>

[ Upstream commit 8314c212f995bc0d06b54ad02ef0ab4089781540 ]

the charging current uses unsigned int variables, if we step back
if the current is still low, we would run into negative which
means setting the target to a huge value.
Better add checks here.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/power/supply/twl4030_charger.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/twl4030_charger.c b/drivers/power/supply/twl4030_charger.c
index bcd4dc304f270..14fed11e8f6e3 100644
--- a/drivers/power/supply/twl4030_charger.c
+++ b/drivers/power/supply/twl4030_charger.c
@@ -449,7 +449,8 @@ static void twl4030_current_worker(struct work_struct *data)

if (v < USB_MIN_VOLT) {
/* Back up and stop adjusting. */
- bci->usb_cur -= USB_CUR_STEP;
+ if (bci->usb_cur >= USB_CUR_STEP)
+ bci->usb_cur -= USB_CUR_STEP;
bci->usb_cur_target = bci->usb_cur;
} else if (bci->usb_cur >= bci->usb_cur_target ||
bci->usb_cur + USB_CUR_STEP > USB_MAX_CURRENT) {
--
2.20.1