2019-07-01 15:50:07

by Jean-Jacques Hiblot

Subject: [PATCH 4/4] devicetree: Add led-backlight binding

From: Tomi Valkeinen <[email protected]>

Add DT binding for led-backlight.

Signed-off-by: Tomi Valkeinen <[email protected]>
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
Cc: [email protected]
---
.../video/backlight/led-backlight.txt | 39 +++++++++++++++++++
1 file changed, 39 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..216cd52d624a
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/backlight/led-backlight.txt
@@ -0,0 +1,39 @@
+led-backlight bindings
+
+The node of the backlight driver IS the node of the LED.
+
+Required properties:
+ - compatible: "led-backlight"
+ - 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[0])
+
+[0]: Documentation/devicetree/bindings/gpio/gpio.txt
+
+Example:
+
+led_ctrl {
+ red_led@1 {
+ label = "red";
+ reg = <1>;
+ }
+
+ backlight_led@2 {
+ function = LED_FUNCTION_BACKLIGHT;
+ reg = <2>;
+
+ compatible = "led-backlight";
+
+ brightness-levels = <0 4 8 16 32 64 128 255>;
+ default-brightness-level = <6>;
+
+ power-supply = <&vdd_bl_reg>;
+ enable-gpios = <&gpio 58 0>;
+ };
+};
--
2.17.1

2019-07-02 09:59:58

by Daniel Thompson

Subject: Re: [PATCH 4/4] devicetree: Add led-backlight binding

On Mon, Jul 01, 2019 at 05:14:23PM +0200, Jean-Jacques Hiblot wrote:
> From: Tomi Valkeinen <[email protected]>
>
> Add DT binding for led-backlight.

I think the patchset is in the wrong order; the DT bindings
documentation should appear *before* the binding is
implemented (amoung other things this prevent transient checkpatch
warnings as the patchset is applied).


>
> Signed-off-by: Tomi Valkeinen <[email protected]>
> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
> Cc: [email protected]
> ---
> .../video/backlight/led-backlight.txt | 39 +++++++++++++++++++
> 1 file changed, 39 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..216cd52d624a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/video/backlight/led-backlight.txt
> @@ -0,0 +1,39 @@
> +led-backlight bindings
> +
> +The node of the backlight driver IS the node of the LED.
> +
> +Required properties:
> + - compatible: "led-backlight"
> + - 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)

I think brightness-levels and default-brightness-level could be
optional properties since a default 1:1 mapping seems reasonable given
how constrained the LED brightness values are.


Daniel.


> +
> +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[0])
> +
> +[0]: Documentation/devicetree/bindings/gpio/gpio.txt
> +
> +Example:
> +
> +led_ctrl {
> + red_led@1 {
> + label = "red";
> + reg = <1>;
> + }
> +
> + backlight_led@2 {
> + function = LED_FUNCTION_BACKLIGHT;
> + reg = <2>;
> +
> + compatible = "led-backlight";
> +
> + brightness-levels = <0 4 8 16 32 64 128 255>;
> + default-brightness-level = <6>;
> +
> + power-supply = <&vdd_bl_reg>;
> + enable-gpios = <&gpio 58 0>;
> + };
> +};
> --
> 2.17.1
>

2019-07-02 11:12:55

by Jean-Jacques Hiblot

Subject: Re: [PATCH 4/4] devicetree: Add led-backlight binding

Daniel,

On 02/07/2019 11:58, Daniel Thompson wrote:
> On Mon, Jul 01, 2019 at 05:14:23PM +0200, Jean-Jacques Hiblot wrote:
>> From: Tomi Valkeinen <[email protected]>
>>
>> Add DT binding for led-backlight.
> I think the patchset is in the wrong order; the DT bindings
> documentation should appear *before* the binding is
> implemented (amoung other things this prevent transient checkpatch
> warnings as the patchset is applied).
>
ok
>> Signed-off-by: Tomi Valkeinen <[email protected]>
>> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
>> Cc: [email protected]
>> ---
>> .../video/backlight/led-backlight.txt | 39 +++++++++++++++++++
>> 1 file changed, 39 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..216cd52d624a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/video/backlight/led-backlight.txt
>> @@ -0,0 +1,39 @@
>> +led-backlight bindings
>> +
>> +The node of the backlight driver IS the node of the LED.
>> +
>> +Required properties:
>> + - compatible: "led-backlight"
>> + - 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)
> I think brightness-levels and default-brightness-level could be
> optional properties since a default 1:1 mapping seems reasonable given
> how constrained the LED brightness values are.

That is probably a good idea. Expect it in v2

Thanks,

JJ

>
>
> Daniel.
>
>
>> +
>> +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[0])
>> +
>> +[0]: Documentation/devicetree/bindings/gpio/gpio.txt
>> +
>> +Example:
>> +
>> +led_ctrl {
>> + red_led@1 {
>> + label = "red";
>> + reg = <1>;
>> + }
>> +
>> + backlight_led@2 {
>> + function = LED_FUNCTION_BACKLIGHT;
>> + reg = <2>;
>> +
>> + compatible = "led-backlight";
>> +
>> + brightness-levels = <0 4 8 16 32 64 128 255>;
>> + default-brightness-level = <6>;
>> +
>> + power-supply = <&vdd_bl_reg>;
>> + enable-gpios = <&gpio 58 0>;
>> + };
>> +};
>> --
>> 2.17.1
>>

2019-07-05 10:12:42

by Pavel Machek

Subject: Re: [PATCH 4/4] devicetree: Add led-backlight binding

Hi!

> Add DT binding for led-backlight.
>
> Signed-off-by: Tomi Valkeinen <[email protected]>
> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
> Cc: [email protected]
> ---

> +Required properties:
> + - compatible: "led-backlight"
> + - brightness-levels: Array of distinct LED brightness levels. These
> + are in the range from 0 to 255, passed to the LED class driver.

These days, we support more (or less) than 256 brightness levels for LED.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html