duty_ns * (1 << PWM_DUTY_WIDTH) could overflow in integer calculation
when the PWM rate is low. Hence do all calculation on unsigned long long
to avoid overflow.
Signed-off-by: NHyong Bin Kim <hyongbink@nvidia.com>
Signed-off-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>