linux-kernel - Re: [RESEND PATCH v5 2/5] dt-bindings: pwm-backlight: add PWM delay proprieties.

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Message-ID: <20180219111136.jpv4wtcm6h2hfwac@oak.lan>
Date:   Mon, 19 Feb 2018 11:11:36 +0000
From:   Daniel Thompson <daniel.thompson@...aro.org>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Lee Jones <lee.jones@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Rob Herring <robh+dt@...nel.org>, Pavel Machek <pavel@....cz>,
        Heiko Stuebner <heiko@...ech.de>,
        Thierry Reding <thierry.reding@...il.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Richard Purdie <rpurdie@...ys.net>,
        Jacek Anaszewski <jacek.anaszewski@...il.com>,
        linux-pwm@...r.kernel.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, groeck@...omium.org,
        linux-rockchip@...ts.infradead.org, kernel@...labora.com
Subject: Re: [RESEND PATCH v5 2/5] dt-bindings: pwm-backlight: add PWM delay
 proprieties.

On Fri, Feb 16, 2018 at 06:40:31PM +0100, Enric Balletbo i Serra wrote:
> Hardware needs a delay between setting an initial (non-zero) PWM and
> enabling the backlight using GPIO. The post-pwm-on-delay-ms specifies
> this delay in milli seconds. Hardware also needs a delay between disabing
> the backlight using GPIO and setting PWM value to 0. The pwm-off-delay-ms
> is this delay in milli seconds.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> Acked-by: Pavel Machek <pavel@....cz>

Acked-by: Daniel Thompson <daniel.thompson@...aro.org>

> ---
> Based on the original Huang Lin <hl@...k-chips.com> work.
> 
> Changes since v4:
>  - Rebase on top of mainline.
> Changes since v3:
>  - Replace us for ms.
>  - Add Acked-by: Pavel Machek <pavel@....cz>
> Changes since v2:
>  - Use separate properties (Rob Herring)
> Changes since v1:
>  - As suggested by Daniel Thompson
>    - Do not assume power-on delay and power-off delay will be the same
> 
>  Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt
> index 764db86d441a..310810906613 100644
> --- a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt
> +++ b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt
> @@ -17,6 +17,10 @@ Optional properties:
>                 "pwms" property (see PWM binding[0])
>    - enable-gpios: contains a single GPIO specifier for the GPIO which enables
>                    and disables the backlight (see GPIO binding[1])
> +  - post-pwm-on-delay-ms: Delay in ms between setting an initial (non-zero) PWM
> +                          and enabling the backlight using GPIO.
> +  - pwm-off-delay-ms: Delay in ms between disabling the backlight using GPIO
> +                      and setting PWM value to 0.
>  
>  [0]: Documentation/devicetree/bindings/pwm/pwm.txt
>  [1]: Documentation/devicetree/bindings/gpio/gpio.txt
> @@ -32,4 +36,6 @@ Example:
>  
>  		power-supply = <&vdd_bl_reg>;
>  		enable-gpios = <&gpio 58 0>;
> +		post-pwm-on-delay-ms = <10>;
> +		pwm-off-delay-ms = <10>;
>  	};
> -- 
> 2.15.1
>