On Thu, Jun 25, 2020 at 8:26 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
>
> From: Dien Pham <dien.pham.ry@xxxxxxxxxxx>
>
> 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, there is better to rename it in a further patch as
> cleanup.
>
> Signed-off-by: Van Do <van.do.xw@xxxxxxxxxxx>
> Signed-off-by: Dien Pham <dien.pham.ry@xxxxxxxxxxx>
> [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@xxxxxxxxxxx>
> Reviewed-by: Niklas Soderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> Tested-by: Niklas Soderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
Reviewed-by: Amit Kucheria <amit.kucheria@xxxxxxxxxx>
> ---
> Changes from v2:
> - Add Niklas-san's Reviewed-by and Tested-by.
> - Keep the variable name "reg" and revise the commit description for it.
> https://patchwork.kernel.org/patch/11595327/
>
> Changes from v1:
> - Use int instead of long.
> - Rename "reg" with "ctemp".
> https://patchwork.kernel.org/patch/11593051/
>
> 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 58fe7c1..c48c5e9 100644
> --- a/drivers/thermal/rcar_gen3_thermal.c
> +++ b/drivers/thermal/rcar_gen3_thermal.c
> @@ -167,7 +167,7 @@ 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;
> --
> 2.7.4
>
