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 name "reg" is not good because it should
be the same type as rcar_gen3_thermal_read(). So, rename it with "ctemp".
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>
---
Changes from v1:
- Use int instead of long.
- Rename "reg" with "ctemp".
https://patchwork.kernel.org/patch/11593051/
drivers/thermal/rcar_gen3_thermal.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c
index 58fe7c1..49ea330 100644
--- a/drivers/thermal/rcar_gen3_thermal.c
+++ b/drivers/thermal/rcar_gen3_thermal.c
@@ -167,16 +167,16 @@ static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
{
struct rcar_gen3_thermal_tsc *tsc = devdata;
int mcelsius, val;
- u32 reg;
+ int ctemp;
/* Read register and convert to mili Celsius */
- reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
+ ctemp = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
- if (reg <= thcode[tsc->id][1])
- val = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1,
+ if (ctemp <= thcode[tsc->id][1])
+ val = FIXPT_DIV(FIXPT_INT(ctemp) - tsc->coef.b1,
tsc->coef.a1);
else
- val = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2,
+ val = FIXPT_DIV(FIXPT_INT(ctemp) - tsc->coef.b2,
tsc->coef.a2);
mcelsius = FIXPT_TO_MCELSIUS(val);
--
2.7.4
