Re: [RFC][PATCH V2 3/3] tegra: add pwm backlight device tree nodes
From: Simon Glass <hidden>
Date: 2012-07-12 09:37:37
Also in:
linux-devicetree, linux-fbdev, lkml
Hi Alex, On Mon, Jul 9, 2012 at 8:08 AM, Alexandre Courbot [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Signed-off-by: Alexandre Courbot <redacted> --- arch/arm/boot/dts/tegra20-ventana.dts | 31 +++++++++++++++++++++++++++++++ arch/arm/boot/dts/tegra20.dtsi | 2 +- 2 files changed, 32 insertions(+), 1 deletion(-)diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts index be90544..c67d9e1 100644 --- a/arch/arm/boot/dts/tegra20-ventana.dts +++ b/arch/arm/boot/dts/tegra20-ventana.dts@@ -317,6 +317,37 @@ bus-width = <8>; };
I would like to do something similar in U-Boot for Tegra, although perhaps not right away. For now I will go with something considerably simpler! But if this is merged into the kernel we will move to it in U-Boot. Anyway here are my comments:
+ backlight {
+ compatible = "pwm-backlight";
+ brightness-levels = <0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 255>;We seem to have a lot of these - should we move to a range and step size?
+ default-brightness-level = <12>; + + pwms = <&pwm 2 5000000>; + pwm-names = "backlight"; + power-supply = <&backlight_reg>; + enable-gpios = <&gpio 28 0>; + + power-on-sequence = "REGULATOR", "power", <1>, + "DELAY", <10>, + "PWM", "backlight", <1>, + "GPIO", "enable", <1>;
So the names REGULATOR, DELAY, etc. here are looked up through some
existing mechanism? In general I am not a big fan of mixing strings
and numbers in a property. Maybe something like:
power_on_sequence {
step@0 {
phandle = <&backlight_reg>;
enable = <1>;
post-delay = <10>;
}
step@1 {
phandle = <&pwm 2 5000000>;
}
step@2 {
phandle = <&gpio 28 0>;
enable = <1>;
}
quoted hunk ↗ jump to hunk
+ power-off-sequence = "GPIO", "enable", <0>, + "PWM", "backlight", <0>, + "DELAY", <10>, + "REGULATOR", "power", <0>; + }; + + backlight_reg: fixedregulator@176 { + compatible = "regulator-fixed"; + regulator-name = "backlight_regulator"; + regulator-min-microvolt = <1800000>; + regulator-max-microvolt = <1800000>; + gpio = <&gpio 176 0>; + startup-delay-us = <0>; + enable-active-high; + regulator-boot-off; + }; + sound { compatible = "nvidia,tegra-audio-wm8903-ventana", "nvidia,tegra-audio-wm8903";diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi index 405d167..67a6cd9 100644 --- a/arch/arm/boot/dts/tegra20.dtsi +++ b/arch/arm/boot/dts/tegra20.dtsi@@ -123,7 +123,7 @@ status = "disabled"; }; - pwm { + pwm: pwm { compatible = "nvidia,tegra20-pwm"; reg = <0x7000a000 0x100>; #pwm-cells = <2>; --1.7.11.1 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Regards, Simon