On Tue, Oct 03, 2023 at 09:43:15AM +0000, Flavio Suligoi wrote:

Hi Daniel,

...

quoted

quoted

+required:
+  - compatible
+  - reg
+  - max-brightness

Why is this mandatory?

There's no point in setting max-brightness when running in I2C mode (max-
brightness should default to 31 in that case).

quoted

+  - default-brightness

Again. I'm not clear why this needs to be mandatory.

Ok, you are right, I'll remove max-brightness and default-brightness
from required properties list. I think to change these properties,
for the pwm dimming, into a clearer:

- brightness-levels (uint32)
- default-brightness-levels (uint32).

For example:

  brightness-levels:
    description:
      Number of brightness levels. The actual brightness
      level (PWM duty cycle) will be interpolated from 0 to this value.
      0 means a  0% duty cycle (darkest/off), while the brightness-levels represents
      a 100% duty cycle (brightest).
    $ref: /schemas/types.yaml#/definitions/uint32

  default-brightness-level:
    description:
      The default brightness level (from 0 to brightness-levels)
    $ref: /schemas/types.yaml#/definitions/uint32

Example:
brightness-levels = <10>;
default-brightness-level = <6>;

What do you think about this solution?

If you want to introduce a brightness-levels property then I would
expect it to be defined with the same meaning as pwm-backlight (it's not
relevant to the bindings but ideally it would be implemented by
refactoring and reusing the code from pwm_bl.c).

Same with default-brightness-level although I'm not sure why one
wouldn't just use default-brightness for new bindings (doesn't
default-brightness-level simply do exactly the same thing as
default-brightness).


Daniel.