Re: [PATCH v2 1/3] pwm: rockchip: Don't update the state for the caller of pwm_apply_state()

Heiko Stuebner
2019-03-30T09:17:42Z

Hi,

[adding two chromeos people, because veyron and gru are quite
heavy users of the rockchip pwm for both backlight and regulators]

Doug, Brian: patchwork patch is here:
https://patchwork.kernel.org/patch/10851001/

Am Dienstag, 12. März 2019, 22:46:03 CET schrieb Uwe Kleine-König:
> The pwm-rockchip driver is one of only two PWM drivers which updates the
> state for the caller of pwm_apply_state(). This might have surprising
> results if the caller reuses the values expecting them to still
> represent the same state. Also note that this feedback was incomplete as
> the matching struct pwm_device::state wasn't updated and so
> pwm_get_state still returned the originally requested state.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

I've tested this on both veyron and gru with backlight and pwm regulator
and at least both still come up, so
Tested-by: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>

But hopefully Doug or Brian could also provide another test-point.

Heiko

> ---
> drivers/pwm/pwm-rockchip.c | 6 ------
> 1 file changed, 6 deletions(-)
>
> diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
> index 4d99d468df09..16186bcd99e0 100644
> --- a/drivers/pwm/pwm-rockchip.c
> +++ b/drivers/pwm/pwm-rockchip.c
> @@ -215,12 +215,6 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> goto out;
> }
>
> - /*
> - * Update the state with the real hardware, which can differ a bit
> - * because of period/duty_cycle approximation.
> - */
> - rockchip_pwm_get_state(chip, pwm, state);
> -
> out:
> clk_disable(pc->pclk);
>
>