From: Ondrej Jirman <megous@xxxxxxxxxx> [ Upstream commit a43ab30dcd4a1abcdd0d2461bf1cf7c0817f6cd3 ] When doing a 16-bit read that returns data in the MSB byte, the RSB_DATA register will keep the MSB byte unchanged when doing the following 8-bit read. sunxi_rsb_read() will then return a result that contains high byte from 16-bit read mixed with the 8-bit result. The consequence is that after this happens the PMIC's regmap will look like this: (0x33 is the high byte from the 16-bit read) % cat /sys/kernel/debug/regmap/sunxi-rsb-3a3/registers 00: 33 01: 33 02: 33 03: 33 04: 33 05: 33 06: 33 07: 33 08: 33 09: 33 0a: 33 0b: 33 0c: 33 0d: 33 0e: 33 [snip] Fix this by masking the result of the read with the correct mask based on the size of the read. There are no 16-bit users in the mainline kernel, so this doesn't need to get into the stable tree. Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx> Acked-by: Chen-Yu Tsai <wens@xxxxxxxx> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/bus/sunxi-rsb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c index 1b76d95859027..2ca2cc56bcef6 100644 --- a/drivers/bus/sunxi-rsb.c +++ b/drivers/bus/sunxi-rsb.c @@ -345,7 +345,7 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr, if (ret) goto unlock; - *buf = readl(rsb->regs + RSB_DATA); + *buf = readl(rsb->regs + RSB_DATA) & GENMASK(len * 8 - 1, 0); unlock: mutex_unlock(&rsb->lock); -- 2.20.1
