[Intel-gfx] [PATCH 1/2] pinctrl: baytrail: Add GPIO lookup and pinctrl-map for i915 DSI panel ctrl

[Andy Shevchenko]

On Fri, Nov 29, 2019 at 07:58:35PM +0100, Hans de Goede wrote:
> On Bay Trail devices the MIPI power on/off sequences for DSI LCD panels
> do not control the LCD panel and backlight GPIOs. So far we have been
> relying on these GPIOs being configured as output and driven high by
> the Video BIOS (GOP) when it initializes the panel.
> 
> This does not work when the device is booted with a HDMI monitor connected
> as then the GOP will initialize the HDMI instead of the panel, leaving the
> panel black, even though the i915 driver tries to output an image to it.
> 
> Likewise on some device-models when the GOP does not initialize the DSI
> panel it also leaves the mux of the PWM0 pin in generic GPIO mode instead
> of muxing it to the PWM controller.
> 
> This commit adds GPIO lookups and a pinctrl-map which the i915 driver can
> use to get the panel- and backlight-enable GPIOs and to mux the PWM0 pin
> to the PWM controller.
> 
> Note it may seem a bit weird to add a pinctrl-map for the i915 driver,
> so that it can set the PWM0 pinmux. Doing this from the LPSS PWM driver
> would be more logical. But the only thing telling us that the pin should
> definitely be muxed to the PWM controller is the VBT to which the PWM
> driver does not have access.

My concern here, as one of Linus', is a pollution the driver with board code.
Aren't we able to split this to a separate file under PDx86 realm and do nasty
quirks there?

-- 
With Best Regards,
Andy Shevchenko