thermal/drivers/rcar_gen3: Fix undefined temperature if negative

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

Signed-off-by: Van Do <>
Signed-off-by: Dien Pham <>
[shimoda: minor fixes, add Fixes tag]
Fixes: 564e73d283af ("thermal: rcar_gen3_thermal: Add R-Car Gen3 thermal driver")
Signed-off-by: Yoshihiro Shimoda <>
Reviewed-by: Niklas Soderlund <>
Tested-by: Niklas Soderlund <>
Reviewed-by: Amit Kucheria <>
Signed-off-by: Daniel Lezcano <>
1 file changed