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gt510wifi: Turn off backlight IC when turning off display #40

Minecrell opened this issue Nov 4, 2019 · 0 comments


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@Minecrell Minecrell commented Nov 4, 2019

We discussed this for #33, but it seemed a bit complicated to implement for the moment:

  • The backlight IC does not remember its configuration when turned off, so it cannot be modeled as simple GPIO or regulator-fixed.
  • There is an existing driver for lp588x, but it does not integrate very well with the way the LP8558 is used on gt510wifi:
    • lp855x supports setting the brightness either through a register or through a PWM signal
    • on gt510wifi that PWM signal is generated by the panel controller and only controllable via the MIPI DCS brightness commands, therefore there is no pure PWM driver for it

So we would need to find a good way to integrate this into the kernel abstractions.

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