[PATCH v4 2/5] dt-bindings: pwm-backlight: add PWM delay proprieties.

[Enric Balletbo i Serra]

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 at collabora.com>
Acked-by: Pavel Machek <pavel at ucw.cz>
---
Based on the original Huang Lin <hl at rock-chips.com> work.

Changes since v3:
 - Replace us for ms.
 - Add Acked-by: Pavel Machek <pavel at 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 764db86..3108109 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>;
 	};
-- 
2.9.3