| Message ID | 20191009085127.22843-6-jjhiblot@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add a generic driver for LED-based backlight | expand |
On Wed, Oct 09, 2019 at 10:51:26AM +0200, Jean-Jacques Hiblot wrote: > Add DT binding for led-backlight. > > Cc: devicetree@vger.kernel.org > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> > > --- > > .../leds/backlight/led-backlight.yaml | 55 +++++++++++++++++++ > 1 file changed, 55 insertions(+) > create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml > > diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml > new file mode 100644 > index 000000000000..47ae3d6b4f31 > --- /dev/null > +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml > @@ -0,0 +1,55 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/leds/backlight/led-backlight.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: LED-based Backlight Device Tree Bindings > + > +maintainers: > + - Jean-Jacques Hiblot <jjhiblot@ti.com> > + > +description: | > + This binding is used to describe a basic backlight device made of LEDs. > + It can also be used to describe a backlight device controlled by the > + output of a LED driver. > + > +properties: > + compatible: > + const: led-backlight > + > + leds: > + $ref: /schemas/types.yaml#/definitions/phandle-array > + description: List of LEDs constitutive of the backlight. > + > + default-brightness: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: Default brightness level on boot. It's not clear that this is an index when 'brightness-levels' is present and absolute level when not. I wonder if we've been consistent on that? > + minimum: 0 Implied by being a uint32. > + > + brightness-levels: > + $ref: /schemas/types.yaml#/definitions/uint32-array > + description: Array of distinct brightness levels. The levels must be in > + the range accepted by the underlying LED devices. This is used to > + translate a backlight brightness level into a LED brightness level. If > + it is not provided, the identity mapping is used. > + > +required: > + - compatible > + - backlight-leds leds? Add 'additionalProperties: false' here. > + > +examples: > + - | > + backlight { Please also define $nodename is 'backlight'. > + compatible = "led-backlight"; > + backlight-leds = <&led1>; leds? > + brightness-levels = <0 4 8 16 32 64 128 255>; > + default-brightness = <6>; /*6th level => brightness of the LEDs is 128*/ > + }; > + - | > + backlight { > + compatible = "led-backlight"; > + backlight-leds = <&led1>, <&led2>; > + default-brightness = <255>; > + }; > +... > -- > 2.17.1 >
Hi, * Rob Herring <robh@kernel.org> [700101 00:00]: > On Wed, Oct 09, 2019 at 10:51:26AM +0200, Jean-Jacques Hiblot wrote: > > Add DT binding for led-backlight. ... > > new file mode 100644 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml ... > > + default-brightness: > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + description: Default brightness level on boot. > > It's not clear that this is an index when 'brightness-levels' is present > and absolute level when not. I wonder if we've been consistent on that? Yeah.. And should we use "default-brightness-level" here like we do in the kernel now? Sorry if I've missed some discussion on this before.. > > + brightness-levels = <0 4 8 16 32 64 128 255>; What we're using for droid4 with an earlier version of this patch set for the brightness-levels is generated backwards with: $ for i in 0 1 2 3 4 5 6 7; do echo "255 - ${i} * (256 / 8)" | bc; done This produces the following range that seem to behave nicely: brightness-levels = <31 63 95 127 159 191 223 255>; Of course depends on the backing hardware, this is with leds_lm3532 on droid4. But I think also the current example in the binding might be from Pavel also for droid4? If so, you might want to update the range :) Regards, Tony
diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml new file mode 100644 index 000000000000..47ae3d6b4f31 --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml @@ -0,0 +1,55 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/leds/backlight/led-backlight.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: LED-based Backlight Device Tree Bindings + +maintainers: + - Jean-Jacques Hiblot <jjhiblot@ti.com> + +description: | + This binding is used to describe a basic backlight device made of LEDs. + It can also be used to describe a backlight device controlled by the + output of a LED driver. + +properties: + compatible: + const: led-backlight + + leds: + $ref: /schemas/types.yaml#/definitions/phandle-array + description: List of LEDs constitutive of the backlight. + + default-brightness: + $ref: /schemas/types.yaml#/definitions/uint32 + description: Default brightness level on boot. + minimum: 0 + + brightness-levels: + $ref: /schemas/types.yaml#/definitions/uint32-array + description: Array of distinct brightness levels. The levels must be in + the range accepted by the underlying LED devices. This is used to + translate a backlight brightness level into a LED brightness level. If + it is not provided, the identity mapping is used. + +required: + - compatible + - backlight-leds + +examples: + - | + backlight { + compatible = "led-backlight"; + backlight-leds = <&led1>; + brightness-levels = <0 4 8 16 32 64 128 255>; + default-brightness = <6>; /*6th level => brightness of the LEDs is 128*/ + }; + - | + backlight { + compatible = "led-backlight"; + backlight-leds = <&led1>, <&led2>; + default-brightness = <255>; + }; +...
Add DT binding for led-backlight. Cc: devicetree@vger.kernel.org Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> --- .../leds/backlight/led-backlight.yaml | 55 +++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml