commit b1fdcfbdb93cc899d19091a2385edb40a07420e3
author Andreas Kemnade <andreas@kemnade.info> Mon Sep 17 07:20:35 2018 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Wed Nov 20 18:00:14 2019 +0100
tree cef0c510df37832161aca47e954323e68a33e41f
parent dcd758c0346d1f03fca83ac4f5b8b1f589a3cda1

power: supply: twl4030_charger: fix charging current out-of-bounds

[ 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

diff --git a/drivers/power/supply/twl4030_charger.c b/drivers/power/supply/twl4030_charger.c
index 0cc12bf..d3cba95 100644
--- a/drivers/power/supply/twl4030_charger.c
+++ b/drivers/power/supply/twl4030_charger.c
@@ -420,7 +420,8 @@
 
 	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) {