Re: [PATCH v3 4/5] arm64: dts: sun50i-a64-pinephone: Enable LCD support on PinePhone

From: Pavel Machek
Date: Fri May 29 2020 - 12:27:33 EST


Hi!

> PinePhone uses PWM backlight and a XBD599 LCD panel over DSI for
> display.
>
> Backlight levels curve was optimized by Martijn Braam using a
> lux meter.

If it was possible to preserve lux values for individual settings in
the comment somewhere... that would be nice :-).

One day, it would be nice to have brightness settings in lux, so I
could easily set matching levels on multiple devices, for example...

Best regards,

Pavel

> +
> +&backlight {
> + power-supply = <&reg_ldo_io0>;
> + /*
> + * PWM backlight circuit on this PinePhone revision was changed since
> + * 1.0, and the lowest PWM duty cycle that doesn't lead to backlight
> + * being off is around 20%. Duty cycle for the lowest brightness level
> + * also varries quite a bit between individual boards, so the lowest
> + * value here was chosen as a safe default.
> + */
> + brightness-levels = <
> + 774 793 814 842
> + 882 935 1003 1088
> + 1192 1316 1462 1633
> + 1830 2054 2309 2596
> + 2916 3271 3664 4096>;
> + num-interpolated-steps = <50>;
> + default-brightness-level = <400>;

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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