[1/2] dt-bindings: leds: Add DT binding for Richtek RT8515

Add a YAML devicetree binding for the Richtek RT8515
dual channel flash/torch LED driver.

Cc: newbytee@protonmail.com
Cc: Stephan Gerhold <stephan@gerhold.net>
Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 .../bindings/leds/richtek,rt8515.yaml         | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/richtek,rt8515.yaml

Hi Linus,

On 8/12/20 11:07 AM, Linus Walleij wrote:
> Add a YAML devicetree binding for the Richtek RT8515
> dual channel flash/torch LED driver.
> 
> Cc: newbytee@protonmail.com
> Cc: Stephan Gerhold <stephan@gerhold.net>
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>   .../bindings/leds/richtek,rt8515.yaml         | 54 +++++++++++++++++++
>   1 file changed, 54 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
> new file mode 100644
> index 000000000000..579ef8a2e40a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
> @@ -0,0 +1,54 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/richtek,rt8515.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Richtek RT8515 1.5A dual channel LED driver
> +
> +maintainers:
> +  - Linus Walleij <linus.walleij@linaro.org>
> +
> +description: |
> +  The Richtek RT8515 is a dual channel (two mode) LED driver that
> +  supports driving a white LED in flash or torch mode.
> +
> +properties:
> +  compatible:
> +    const: richtek,rt8515
> +
> +  enf-gpios:
> +    maxItems: 1
> +    description: A connection to the 'ENF' (enable flash) pin.
> +
> +  ent-gpios:
> +    maxItems: 1
> +    description: A connection to the 'ENT' (enable torch) pin.
> +
> +  led:
> +    type: object
> +    $ref: common.yaml#
> +
> +required:
> +  - compatible
> +  - ent-gpios
> +  - enf-gpios
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/leds/common.h>
> +
> +    led-controller {
> +        compatible = "richtek,rt8515";
> +        enf-gpios = <&gpio4 12 GPIO_ACTIVE_HIGH>;
> +        ent-gpios = <&gpio4 13 GPIO_ACTIVE_HIGH>;
> +
> +        led {
> +            function = LED_FUNCTION_FLASH;
> +            color = <LED_COLOR_ID_WHITE>;
> +            flash-max-timeout-us = <250000>;

Constraints for this property are needed above.

> +        };
> +    };
>

On Thu, Aug 13, 2020 at 11:06 PM Jacek Anaszewski
<jacek.anaszewski@gmail.com> wrote:

> > +  led:
> > +    type: object
> > +    $ref: common.yaml#
(...)
> > +        led {
> > +            function = LED_FUNCTION_FLASH;
> > +            color = <LED_COLOR_ID_WHITE>;
> > +            flash-max-timeout-us = <250000>;
>
> Constraints for this property are needed above.

Can you elaborate on what you expect this to look like?
The property is from common.yaml, so should that be
extended with a constraint?

Yours,
Linus Walleij

On 8/19/20 11:05 PM, Linus Walleij wrote:
> On Thu, Aug 13, 2020 at 11:06 PM Jacek Anaszewski
> <jacek.anaszewski@gmail.com> wrote:
> 
>>> +  led:
>>> +    type: object
>>> +    $ref: common.yaml#
> (...)
>>> +        led {
>>> +            function = LED_FUNCTION_FLASH;
>>> +            color = <LED_COLOR_ID_WHITE>;
>>> +            flash-max-timeout-us = <250000>;
>>
>> Constraints for this property are needed above.
> 
> Can you elaborate on what you expect this to look like?
> The property is from common.yaml, so should that be
> extended with a constraint?

Constraints are specific to the hardware, so those should
be provided in the related bindings.
Generally it is customary in similar cases to give min, max
and step values.

I don't have json-schema example, but see old txt DT bindings:

- Documentation/devicetree/bindings/leds/leds-lm3601x.txt
- Documentation/devicetree/bindings/mfd/max77693.txt

Hi!

> >>>+        led {
> >>>+            function = LED_FUNCTION_FLASH;
> >>>+            color = <LED_COLOR_ID_WHITE>;
> >>>+            flash-max-timeout-us = <250000>;
> >>
> >>Constraints for this property are needed above.
> >
> >Can you elaborate on what you expect this to look like?
> >The property is from common.yaml, so should that be
> >extended with a constraint?
> 
> Constraints are specific to the hardware, so those should
> be provided in the related bindings.
> Generally it is customary in similar cases to give min, max
> and step values.

This looks okay to me.

Driver already knows what the step is, so there's no need to specify
it in the device tree. I was always wondering why minimum is useful. I
guess most hardware can just use first step as a minimum, again no
need to specify that.

Best regards,
								Pavel