From: Dien Pham dien.pham.ry@renesas.com
[ Upstream commit 5f8f06425a0dcdad7bedbb77e67f5c65ab4dacfc ]
As description for DIV_ROUND_CLOSEST in file include/linux/kernel.h. "Result is undefined for negative divisors if the dividend variable type is unsigned and for negative dividends if the divisor variable type is unsigned."
In current code, the FIXPT_DIV uses DIV_ROUND_CLOSEST but has not checked sign of divisor before using. It makes undefined temperature value in case the value is negative.
This patch fixes to satisfy DIV_ROUND_CLOSEST description and fix bug too. Note that the variable name "reg" is not good because it should be the same type as rcar_gen3_thermal_read(). However, it's better to rename the "reg" in a further patch as cleanup.
Signed-off-by: Van Do van.do.xw@renesas.com Signed-off-by: Dien Pham dien.pham.ry@renesas.com [shimoda: minor fixes, add Fixes tag] Fixes: 564e73d283af ("thermal: rcar_gen3_thermal: Add R-Car Gen3 thermal driver") Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Reviewed-by: Niklas Soderlund niklas.soderlund+renesas@ragnatech.se Tested-by: Niklas Soderlund niklas.soderlund+renesas@ragnatech.se Reviewed-by: Amit Kucheria amit.kucheria@linaro.org Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org Link: https://lore.kernel.org/r/1593085099-2057-1-git-send-email-yoshihiro.shimoda... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/thermal/rcar_gen3_thermal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c index 755d2b5bd2c2b..1ab2ffff4e7c7 100644 --- a/drivers/thermal/rcar_gen3_thermal.c +++ b/drivers/thermal/rcar_gen3_thermal.c @@ -169,7 +169,7 @@ static int rcar_gen3_thermal_get_temp(void *devdata, int *temp) { struct rcar_gen3_thermal_tsc *tsc = devdata; int mcelsius, val; - u32 reg; + int reg;
/* Read register and convert to mili Celsius */ reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;