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From: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
To: "Uwe Kleine-König"
	<u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Cc: linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Maxime Ripard
	<maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org>,
	briannorris-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
	dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
	Thierry Reding
	<thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org
Subject: Re: [PATCH v2 1/3] pwm: rockchip: Don't update the state for the caller of pwm_apply_state()
Date: Sat, 30 Mar 2019 10:17:42 +0100	[thread overview]
Message-ID: <1707507.TOMHpQGrZ7@phil> (raw)
In-Reply-To: <20190312214605.10223-2-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

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);
>  
> 

  parent reply	other threads:[~2019-03-30  9:17 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-12 21:46 [PATCH v2 0/3] pwm: ensure pwm_apply_state() doesn't modify the state argument Uwe Kleine-König
     [not found] ` <20190312214605.10223-1-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-03-12 21:46   ` [PATCH v2 1/3] pwm: rockchip: Don't update the state for the caller of pwm_apply_state() Uwe Kleine-König
     [not found]     ` <20190312214605.10223-2-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-03-30  9:17       ` Heiko Stuebner [this message]
2019-04-01 22:45         ` Doug Anderson
     [not found]           ` <CAD=FV=WZHouhGcxOgNG3006XajJQaAp0uq9WjeKRikQx1ru4TA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-04-08 14:39             ` Uwe Kleine-König
     [not found]               ` <20190408143914.uucb5dwafq3cnsmk-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-04-19  0:27                 ` Brian Norris
     [not found]                   ` <CA+ASDXO=szekU97iTDK9vqWjT+JtAKeCNTyoY=8aSi5d+v4mkA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-04-29  6:56                     ` Uwe Kleine-König
     [not found]                       ` <20190429065613.n52uwgys5eugmssd-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-04-29 11:18                         ` Thierry Reding
2019-04-29 13:11                           ` Uwe Kleine-König
     [not found]                             ` <20190429131127.x535uhhtputb7zwl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-04-29 16:28                               ` Thierry Reding
2019-04-30  9:14                                 ` Uwe Kleine-König
2019-04-29 18:04                         ` Doug Anderson
     [not found]                           ` <CAD=FV=U71u39ZHkBBfAXVAP=_hY-bAw3L7JdhC=36jkUVxPOmQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-04-30  9:28                             ` Uwe Kleine-König
     [not found]                               ` <20190430092824.ijtq3gfh6mqujvnk-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-04-30 14:38                                 ` Doug Anderson
     [not found]                                   ` <CAD=FV=WUi0NbsRDJA_4WeC62QYXjLNH2OygU1FOCx==W0SyqpQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-05-02  6:48                                     ` Uwe Kleine-König
2019-05-02  7:16                             ` Boris Brezillon
     [not found]                               ` <20190502091638.0f5a40b0-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2019-05-02  7:33                                 ` Uwe Kleine-König
     [not found]                                   ` <20190502073326.sgqgkiexjkipvi27-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-05-02  8:09                                     ` Boris Brezillon
     [not found]                                       ` <20190502100951.23ef9ed1-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2019-05-02  8:42                                         ` Uwe Kleine-König
     [not found]                                           ` <20190502084243.anz5myut63g4torn-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-05-03 10:59                                             ` Thierry Reding
2019-05-03 19:59                                               ` Uwe Kleine-König
2019-04-29 11:03                 ` Thierry Reding
2019-04-29 12:31                   ` Uwe Kleine-König
     [not found]                     ` <20190429123102.7wfcdqusn24g5rm7-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2019-04-29 16:17                       ` Thierry Reding
2019-04-29 21:08                         ` Uwe Kleine-König
2019-04-29 10:49             ` Thierry Reding
2019-03-12 21:46   ` [PATCH v2 2/3] pwm: sun4i: " Uwe Kleine-König
2019-03-12 21:46   ` [PATCH v2 3/3] pwm: ensure pwm_apply_state() doesn't modify the state argument Uwe Kleine-König

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