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

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Message-Id: <20180326095213.18362-2-enric.balletbo@collabora.com>
Date:   Mon, 26 Mar 2018 11:52:10 +0200
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Rob Herring <robh+dt@...nel.org>, Pavel Machek <pavel@....cz>,
        Heiko Stuebner <heiko@...ech.de>
Cc:     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, linux-leds@...r.kernel.org,
        devicetree@...r.kernel.org, kernel@...labora.com
Subject: [PATCH v6 2/5] dt-bindings: pwm-backlight: add PWM delay proprieties.

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: Thierry Reding <thierry.reding@...il.com>
---
Based on the original Huang Lin <hl@...k-chips.com> work.
Changes since v5:
 - Add Acked-by: Thierry Reding <thierry.reding@...il.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@....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