On Thu, Jun 22, 2023 at 5:13 AM Rob Herring <r...@kernel.org> wrote: > > On Thu, Jun 22, 2023 at 12:54:56AM +0300, Alexandru Ardelean wrote: > > From: Yannick Fertre <yannick.fer...@foss.st.com> > > > > Add documentation for new default-brightness-level property. > > Why?
I'll admit, I liked the fact that the "default-brightness-level" is more uniform in the space of backlights. The "default-on" property is more specific to the gpio-backlight driver. And then there's gpio hogging that could also work. > > > > > Signed-off-by: Yannick Fertre <yannick.fer...@foss.st.com> > > Signed-off-by: Alexandru Ardelean <a...@shruggie.ro> > > --- > > > > Link to original patch: > > > > https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98 > > > > Changelog v1 -> v2: > > * https://lore.kernel.org/dri-devel/20230519200520.10657-2-a...@shruggie.ro/ > > * removed 'brightness-levels' reference > > * updated doc-text for 'default-brightness-level' > > * updated doc-text for 'default-on' > > * added 'minimum' & 'maximum' to 'default-brightness-level' property > > * removed 'Reviewed-by: Philippe CORNU <philippe.co...@foss.st.com>' as > > requested > > * patch is first in series of 2 patches (was second patch) > > > > .../bindings/leds/backlight/gpio-backlight.yaml | 14 +++++++++++++- > > 1 file changed, 13 insertions(+), 1 deletion(-) > > > > diff --git > > a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml > > b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml > > index 584030b6b0b9..2da6552a207c 100644 > > --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml > > +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml > > @@ -20,9 +20,21 @@ properties: > > maxItems: 1 > > > > default-on: > > - description: enable the backlight at boot. > > + description: > > + The default power state of the backlight at boot. > > type: boolean > > > > + default-brightness-level: > > + description: > > + The default brightness level on device init. The value can be 0 or 1. > > + If omitted, the value is 1. In the context of the "gpio-backlight" > > driver > > + the effect of this setting will be that the backlight is on/off. > > + The difference between this setting and "default-on" is that this > > handles > > + brightness, while "default-on" handles the power setting of the > > device. > > What power setting? You only have 1 GPIO to control here which is 2 > states. I fail to see why you need 6 possible states with all the > combinations of 2 properties. So, the "default-on" bool gets converted to backlight power settings, which eventually gets converted back to GPIO values (at some point). Which sounds quirky (when saying/writing it). But, yeah. That's one thing that also made me a bit undecided to send this. On the one hand I like the uniformity it brings. On the other hand, because there is the legacy behavior (the "default-on" property, and the fact that we can use the GPIO DT settings to control this) just explodes complexity/quirks. We can probably just drop this. I'll also admit that my doc-writing skills aren't too great. Thanks Alex > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + minimum: 0 > > + maximum: 1 > > + > > required: > > - compatible > > - gpios > > -- > > 2.40.1 > >
