Re: [PATCH] dt-bindings: backlight: Convert common backlight bindings to DT schema

Hi Rob.

Good to have these converted. A few comments in the following. One comment is for the backlight people as you copied the original text.

Sam

On Thu, Jun 18, 2020 at 04:44:13PM -0600, Rob Herring wrote:

Convert the common GPIO, LED, and PWM backlight bindings to DT schema format.

Given there's only 2 common properties and the descriptions are slightly different, I opted to not create a common backlight schema.

Cc: Lee Jones lee.jones@linaro.org Cc: Daniel Thompson daniel.thompson@linaro.org Cc: Jingoo Han jingoohan1@gmail.com Signed-off-by: Rob Herring robh@kernel.org

---

.../leds/backlight/gpio-backlight.txt | 16 --- .../leds/backlight/gpio-backlight.yaml | 41 ++++++++ .../bindings/leds/backlight/led-backlight.txt | 28 ------ .../leds/backlight/led-backlight.yaml | 58 +++++++++++ .../bindings/leds/backlight/pwm-backlight.txt | 61 ------------ .../leds/backlight/pwm-backlight.yaml | 98 +++++++++++++++++++ 6 files changed, 197 insertions(+), 105 deletions(-) delete mode 100644 Documentation/devicetree/bindings/leds/backlight/gpio-backlight.txt create mode 100644 Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml delete mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml delete mode 100644 Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt create mode 100644 Documentation/devicetree/bindings/leds/backlight/pwm-backlight.yaml

diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.txt deleted file mode 100644 index 321be6640533..000000000000 --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.txt +++ /dev/null @@ -1,16 +0,0 @@ -gpio-backlight bindings

-Required properties:

• • compatible: "gpio-backlight"
• • gpios: describes the gpio that is used for enabling/disabling the backlight.
• refer to bindings/gpio/gpio.txt for more details.

-Optional properties:

• • default-on: enable the backlight at boot.

-Example:

• backlight {

• compatible = "gpio-backlight";
  

• gpios = <&gpio3 4 GPIO_ACTIVE_HIGH>;
  

• default-on;
  

• };

diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml new file mode 100644 index 000000000000..75cc569b9c55 --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml @@ -0,0 +1,41 @@ +# SPDX-License-Identifier: GPL-2.0-only +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/leds/backlight/gpio-backlight.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: gpio-backlight bindings

+maintainers:

• • Lee Jones lee.jones@linaro.org
• • Daniel Thompson daniel.thompson@linaro.org
• • Jingoo Han jingoohan1@gmail.com

+properties:

• compatible:
• const: gpio-backlight
• gpios:
• description: The gpio that is used for enabling/disabling the backlight.
• maxItems: 1
• default-on:
• description: enable the backlight at boot.
• type: boolean

+required:

• • compatible
• • gpios

+additionalProperties: false

+examples:

• • |
• #include <dt-bindings/gpio/gpio.h>
• backlight {

•    compatible = "gpio-backlight";
  

•    gpios = <&gpio3 4 GPIO_ACTIVE_HIGH>;
  

•    default-on;
  

• };

+... diff --git a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt deleted file mode 100644 index 4c7dfbe7f67a..000000000000 --- a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt +++ /dev/null @@ -1,28 +0,0 @@ -led-backlight bindings

-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.

-Required properties:

• • compatible: "led-backlight"
• • leds: a list of LEDs

-Optional properties:

• • brightness-levels: 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.
  

• • default-brightness-level: The default brightness level.

-Example:

• backlight {

• compatible = "led-backlight";
  

• leds = <&led1>, <&led2>;
  

• brightness-levels = <0 4 8 16 32 64 128 255>;
  

• default-brightness-level = <6>;
  

• };

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..ae50945d2798 --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/led-backlight.yaml @@ -0,0 +1,58 @@ +# SPDX-License-Identifier: GPL-2.0-only +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/leds/backlight/led-backlight.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: led-backlight bindings

+maintainers:

• • Lee Jones lee.jones@linaro.org
• • Daniel Thompson daniel.thompson@linaro.org
• • Jingoo Han jingoohan1@gmail.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:
• description: A list of LED nodes
• $ref: /schemas/types.yaml#/definitions/phandle-array
• brightness-levels:
• 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.
  

• $ref: /schemas/types.yaml#/definitions/uint32-array

bike-shedding. To me it is a tad easier to read when multi-line descriptions are on a separate line. So "description:" on one line, and the text on following lines. example-schema.yaml does both - so both are official acceptable.

• default-brightness-level:
• description: The default brightness level (index into the array defined

•  by the "brightness-levels" property).
  

This description does not match my understading. The description says "index into", but in reality this is a value that matches somewhere in the range specified by brightness-levels. So it is not an index.

Maybe I just read it wrong and the description is fine. But when I read index the when it says 6 I would look for brightness-levels[6] equals 128 in the example below. And this is not how it is coded.

• $ref: /schemas/types.yaml#/definitions/uint32

+dependencies:

• default-brightness-level: [brightness-levels]

So if we have efault-brightness-level then we must have brightness-levels. Sounds right.

+required:

• • compatible
• • leds

+additionalProperties: false

+examples:

• • |
• backlight {

•    compatible = "led-backlight";
  

•    leds = <&led1>, <&led2>;
  

•    brightness-levels = <0 4 8 16 32 64 128 255>;
  

•    default-brightness-level = <6>;
  

• };

+... diff --git a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt deleted file mode 100644 index 64fa2fbd98c9..000000000000 --- a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt +++ /dev/null @@ -1,61 +0,0 @@ -pwm-backlight bindings

-Required properties:

• • compatible: "pwm-backlight"
• • pwms: OF device-tree PWM specification (see PWM binding[0])
• • power-supply: regulator for supply voltage

-Optional properties:

• • pwm-names: a list of names for the PWM devices specified in the

•           "pwms" property (see PWM binding[0])
  

• • enable-gpios: contains a single GPIO specifier for the GPIO which enables

•              and disables the backlight (see GPIO binding[1])
  

• • post-pwm-on-delay-ms: Delay in ms between setting an initial (non-zero) PWM

•                      and enabling the backlight using GPIO.
  

• • pwm-off-delay-ms: Delay in ms between disabling the backlight using GPIO

•                  and setting PWM value to 0.
  

• • brightness-levels: Array of distinct brightness levels. Typically these

•                   are in the range from 0 to 255, but any range starting at
  

•                   0 will do. The actual brightness level (PWM duty cycle)
  

•                   will be interpolated from these values. 0 means a 0% duty
  

•                   cycle (darkest/off), while the last value in the array
  

•                   represents a 100% duty cycle (brightest).
  

• • default-brightness-level: The default brightness level (index into the

•                          array defined by the "brightness-levels" property).
  

• • num-interpolated-steps: Number of interpolated steps between each value

•                        of brightness-levels table. This way a high
  

•                        resolution pwm duty cycle can be used without
  

•                        having to list out every possible value in the
  

•                        brightness-level array.
  

-[0]: Documentation/devicetree/bindings/pwm/pwm.txt -[1]: Documentation/devicetree/bindings/gpio/gpio.txt

-Example:

• backlight {

• compatible = "pwm-backlight";
  

• pwms = <&pwm 0 5000000>;
  

• brightness-levels = <0 4 8 16 32 64 128 255>;
  

• default-brightness-level = <6>;
  

• power-supply = <&vdd_bl_reg>;
  

• enable-gpios = <&gpio 58 0>;
  

• post-pwm-on-delay-ms = <10>;
  

• pwm-off-delay-ms = <10>;
  

• };

-Example using num-interpolation-steps:

• backlight {

• compatible = "pwm-backlight";
  

• pwms = <&pwm 0 5000000>;
  

• brightness-levels = <0 2048 4096 8192 16384 65535>;
  

• num-interpolated-steps = <2048>;
  

• default-brightness-level = <4096>;
  

• power-supply = <&vdd_bl_reg>;
  

• enable-gpios = <&gpio 58 0>;
  

• };

diff --git a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.yaml new file mode 100644 index 000000000000..7e1f109a38a4 --- /dev/null +++ b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.yaml @@ -0,0 +1,98 @@ +# SPDX-License-Identifier: GPL-2.0-only +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/leds/backlight/pwm-backlight.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: pwm-backlight bindings

+maintainers:

• • Lee Jones lee.jones@linaro.org
• • Daniel Thompson daniel.thompson@linaro.org
• • Jingoo Han jingoohan1@gmail.com

+properties:

• compatible:
• const: pwm-backlight
• pwms:
• maxItems: 1
• pwm-names: true
• power-supply:
• description: regulator for supply voltage
• enable-gpios:
• description: Contains a single GPIO specifier for the GPIO which enables

•  and disables the backlight
  

• maxItems: 1
• post-pwm-on-delay-ms:
• description: Delay in ms between setting an initial (non-zero) PWM and

•  enabling the backlight using GPIO.
  

• pwm-off-delay-ms:
• description: Delay in ms between disabling the backlight using GPIO

•  and setting PWM value to 0.
  

• brightness-levels:
• description: Array of distinct brightness levels. Typically these are

•  in the range from 0 to 255, but any range starting at 0 will do. The
  

•  actual brightness level (PWM duty cycle) will be interpolated from
  

•  these values. 0 means a 0% duty cycle (darkest/off), while the last
  

•  value in the array represents a 100% duty cycle (brightest).
  

• $ref: /schemas/types.yaml#/definitions/uint32-array
• default-brightness-level:
• description: The default brightness level (index into the array defined

•  by the "brightness-levels" property).
  

• $ref: /schemas/types.yaml#/definitions/uint32

Same comment as before...

• num-interpolated-steps:
• description: Number of interpolated steps between each value of brightness-levels

•  table. This way a high resolution pwm duty cycle can be used without
  

•  having to list out every possible value in the brightness-level array.
  

• $ref: /schemas/types.yaml#/definitions/uint32

+dependencies:

• default-brightness-level: [brightness-levels]
• num-interpolated-steps: [brightness-levels]

+required:

• • compatible
• • pwms
• • power-supply

+additionalProperties: false

+examples:

• • |
• backlight {

•    compatible = "pwm-backlight";
  

•    pwms = <&pwm 0 5000000>;
  

•    brightness-levels = <0 4 8 16 32 64 128 255>;
  

•    default-brightness-level = <6>;
  

•    power-supply = <&vdd_bl_reg>;
  

•    enable-gpios = <&gpio 58 0>;
  

•    post-pwm-on-delay-ms = <10>;
  

•    pwm-off-delay-ms = <10>;
  

• };
• • |
• // Example using num-interpolation-steps:
• backlight {

•    compatible = "pwm-backlight";
  

•    pwms = <&pwm 0 5000000>;
  

•    brightness-levels = <0 2048 4096 8192 16384 65535>;
  

•    num-interpolated-steps = <2048>;
  

•    default-brightness-level = <4096>;
  

•    power-supply = <&vdd_bl_reg>;
  

•    enable-gpios = <&gpio 58 0>;
  

• };

+...

2.25.1

---

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