linux-kernel - Re: [PATCH v3 2/2] backlight: pwm_bl: Check the pwm state for initial backlight power state

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Date:   Mon, 21 Nov 2016 09:13:35 +0100
From:   Thierry Reding <thierry.reding@...il.com>
To:     Peter Ujfalusi <peter.ujfalusi@...com>
Cc:     lee.jones@...aro.org, tomi.valkeinen@...com,
        linux-pwm@...r.kernel.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, p.zabel@...gutronix.de
Subject: Re: [PATCH v3 2/2] backlight: pwm_bl: Check the pwm state for
 initial backlight power state

On Tue, Nov 01, 2016 at 02:59:33PM +0200, Peter Ujfalusi wrote:
> If the pwm is not enabled the backlight initially should not be enabled
> either if we have booted with DT and there is a phandle pointing to the
> backlight node.
> 
> The patch extends the checks to decide if we should keep the backlight off
> initially.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
> ---
>  drivers/video/backlight/pwm_bl.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 4b07da278b4f..f680f7b033b2 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -215,6 +215,10 @@ static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb)
>  	if (!regulator_is_enabled(pb->power_supply))
>  		return FB_BLANK_POWERDOWN;
>  
> +	/* The pwm is disabled, keep it like this */
> +	if (!pwm_is_enabled(pb->pwm))
> +		return FB_BLANK_POWERDOWN;
> +
>  	return FB_BLANK_UNBLANK;
>  }

I prefer "PWM" instead of "pwm" in prose (comments and commit message)
because it's an abbreviation.

Otherwise this looks correct:

Reviewed-by: Thierry Reding <treding@...dia.com>

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