On Mon, Oct 14, 2019 at 03:53:03PM +0200, meg...@megous.com wrote:
> From: Ondrej Jirman <meg...@megous.com>
>
> Since 5.4-rc1, pwm_apply_state calls ->get_state after ->apply
> if available, and this revealed an issue with integer precision
> when calculating duty_cycle and period for the currently set
> state in ->get_state callback.
>
> This issue manifested in broken backlight on several Allwinner
> based devices.
>
> Previously this worked, because ->apply updated the passed state
> directly.
>
> Fixes: deb9c462f4e53 ("pwm: sun4i: Don't update the state for the caller of
> pwm_apply_state")
> Signed-off-by: Ondrej Jirman <meg...@megous.com>
> ---
> drivers/pwm/pwm-sun4i.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)Applied, thanks. Thierry > diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c > index 6f5840a1a82d..05273725a9ff 100644 > --- a/drivers/pwm/pwm-sun4i.c > +++ b/drivers/pwm/pwm-sun4i.c > @@ -137,10 +137,10 @@ static void sun4i_pwm_get_state(struct pwm_chip *chip, > > val = sun4i_pwm_readl(sun4i_pwm, PWM_CH_PRD(pwm->hwpwm)); > > - tmp = prescaler * NSEC_PER_SEC * PWM_REG_DTY(val); > + tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_DTY(val); > state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate); > > - tmp = prescaler * NSEC_PER_SEC * PWM_REG_PRD(val); > + tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_PRD(val); > state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate); > } > > -- > 2.23.0 >
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