From 602553073892c18f723f8aa090153a23b1312a16 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Fri, 10 Jun 2016 12:39:57 -0700 Subject: backlight: lp855x: Add enable regulator The LP8556 datasheet describes an EN/VDDIO input, which serves "both as a chip enable and as a power supply reference for PWM, SDA, and SCL inputs." The LP8556 that I'm testing doesn't respond properly if I try to talk I2C to it too quickly after enabling VDDIO, and the LP8555 datasheet mentions a t_RESPONSE delay of up to 1 millisecond. Support this EN/VDDIO by adding a regulator property to the binding; enabling this regulator at probe time; and sleeping for 1 to 2ms, if the EN/VDDIO regulator was provided. Signed-off-by: Brian Norris Acked-by: Rob Herring Acked-by: Milo Kim Reviewed-by: Stephen Barber Signed-off-by: Lee Jones --- Documentation/devicetree/bindings/leds/backlight/lp855x.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation/devicetree/bindings/leds') diff --git a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt index 0a3ecbc3a1b9..88f56641fc28 100644 --- a/Documentation/devicetree/bindings/leds/backlight/lp855x.txt +++ b/Documentation/devicetree/bindings/leds/backlight/lp855x.txt @@ -13,6 +13,7 @@ Optional properties: - rom-addr: Register address of ROM area to be updated (u8) - rom-val: Register value to be updated (u8) - power-supply: Regulator which controls the 3V rail + - enable-supply: Regulator which controls the EN/VDDIO input Example: @@ -57,6 +58,7 @@ Example: backlight@2c { compatible = "ti,lp8557"; reg = <0x2c>; + enable-supply = <&backlight_vddio>; power-supply = <&backlight_vdd>; dev-ctrl = /bits/ 8 <0x41>; -- cgit v1.2.3-59-g8ed1b