vc4-kms-dsi-waveshare-panel overlay with 7_0_inchC about linux

[pelwell]

Any comments, @waveshare?

[6by9]

Display and touch resolutions can differ - see the 7.9" panel where touch has to be defined as 4096x4096.

https://github.com/raspberrypi/linux/blob/rpi-6.1.y/arch/arm/boot/dts/overlays/vc4-kms-dsi-waveshare-panel-overlay.dts#L93-L94 sets the touch resolution.
https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/gpu/drm/panel/panel-waveshare-dsi.c#L80-L93 defines the panel resolution.

I don't have the 7.0" C panel to test with.
Do you have one and are observing issues, or is this purely a code review comment?

[Romain-Donze]

So after tinkering a bit, I found out that my problem was due to the fact that I did'nt set correct params to i2c1 so after adding

dtoverlay=vc4-kms-dsi-waveshare-panel,7_0_inchC,i2c1 to config.txt it works ok with With Raspberry Pi OS Lite. I now have some issue making it work with a custom yocto build so I created an issue in meta-raspberrypi instead

agherzan/meta-raspberrypi#1260

So I guess that if it is intended to write:

7_0_inchC = <&panel>, "compatible=waveshare,7.0inch-c-panel",
<&touch>, "touchscreen-size-x:0=800",
<&touch>, "touchscreen-size-y:0=480";

Then we can close this issue

[pelwell]

If it's working for you, i.e. the display looks correct with no scaling artifacts, and the touchscreen is behaving itself, then I think we're done.