Messages in this thread |  | | Date | Thu, 21 Nov 2019 10:22:28 -0800 | From | Tony Lindgren <> | Subject | Re: [PATCH v10 5/6] dt-bindings: backlight: Add led-backlight binding |
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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
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