Hi Rob, On 13/10/15 17:21, Rob Herring wrote: > On Wed, Sep 30, 2015 at 4:32 AM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote: >> Add DT binding for led-backlight. > > Please use get_maintainers.pl. At some point I got feedback that the DT maintainers don't have time to look at each individual driver binding, but rely on the subsystem maintainers to handle them. Maybe I misunderstood that. >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> >> Cc: devicetree@xxxxxxxxxxxxxxx >> --- >> .../bindings/video/backlight/led-backlight.txt | 30 ++++++++++++++++++++++ >> 1 file changed, 30 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/video/backlight/led-backlight.txt >> >> diff --git a/Documentation/devicetree/bindings/video/backlight/led-backlight.txt b/Documentation/devicetree/bindings/video/backlight/led-backlight.txt >> new file mode 100644 >> index 000000000000..d4621d7414bc >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/video/backlight/led-backlight.txt >> @@ -0,0 +1,30 @@ >> +led-backlight bindings >> + >> +Required properties: >> + - compatible: "led-backlight" >> + - leds: phandle to a led OF node [0] > > Why do we need 2 levels of LED nodes? Sorry, didn't get that. What do you mean with 2 levels? >> + - brightness-levels: Array of distinct LED brightness levels. These >> + are in the range from 0 to 255, passed to the LED class driver. >> + - default-brightness-level: the default brightness level (index into the >> + array defined by the "brightness-levels" property) >> + >> +Optional properties: >> + - power-supply: regulator for supply voltage >> + - enable-gpios: contains a single GPIO specifier for the GPIO which enables >> + and disables the backlight (see GPIO binding[1]) > > Why are all of these not part of the LED node pointed to by leds? These are for the backlight, not for the LED chip. So "LED" here is a chip that produces (most likely) a PWM signal, and "backlight" is the collection of components that use the PWM to produce the backlight itself, and use the power-supply and gpios. > Describe the h/w, not what you want for a driver. I think this describes the HW quite well. The LED chip works fine without any of the properties here, and these are specific to the backlight part of the board. Tomi
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