[v6,2/5] dt-bindings: pwm-backlight: add PWM delay proprieties.

Message ID 20180326095213.18362-2-enric.balletbo@collabora.com
State New
Headers show
Series
  • [v6,1/5] pwm-backlight: enable/disable the PWM before/after LCD enable toggle.
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Commit Message

Enric Balletbo i Serra March 26, 2018, 9:52 a.m.
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@collabora.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
---
Based on the original Huang Lin <hl@rock-chips.com> work.
Changes since v5:
 - Add Acked-by: Thierry Reding <thierry.reding@gmail.com>
 - CC DT mainling list (for some reason dropped at some point, my
   fault)
Changes since v4:
 - Rebase on top of mainline.
Changes since v3:
 - Replace us for ms.
 - Add Acked-by: Pavel Machek <pavel@ucw.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(+)

Comments

Daniel Thompson March 26, 2018, 3:07 p.m. | #1
On Mon, Mar 26, 2018 at 11:52:10AM +0200, 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@collabora.com>
> Acked-by: Pavel Machek <pavel@ucw.cz>
> Acked-by: Thierry Reding <thierry.reding@gmail.com>

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

> ---
> Based on the original Huang Lin <hl@rock-chips.com> work.
> Changes since v5:
>  - Add Acked-by: Thierry Reding <thierry.reding@gmail.com>
>  - CC DT mainling list (for some reason dropped at some point, my
>    fault)
> Changes since v4:
>  - Rebase on top of mainline.
> Changes since v3:
>  - Replace us for ms.
>  - Add Acked-by: Pavel Machek <pavel@ucw.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>;
>  	};
> -- 
> 2.16.2
> 
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Rob Herring March 27, 2018, 3:08 p.m. | #2
On Mon, Mar 26, 2018 at 11:52:10AM +0200, 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@collabora.com>
> Acked-by: Pavel Machek <pavel@ucw.cz>
> Acked-by: Thierry Reding <thierry.reding@gmail.com>
> ---
> Based on the original Huang Lin <hl@rock-chips.com> work.
> Changes since v5:
>  - Add Acked-by: Thierry Reding <thierry.reding@gmail.com>
>  - CC DT mainling list (for some reason dropped at some point, my
>    fault)
> Changes since v4:
>  - Rebase on top of mainline.
> Changes since v3:
>  - Replace us for ms.
>  - Add Acked-by: Pavel Machek <pavel@ucw.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(+)

Reviewed-by: Rob Herring <robh@kernel.org> 
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Patch

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>;
 	};