Inverted and horizontally mirrored display output on i.MX6 SoloX

I have updated my working Kernel 4.19.84 to the broken 5.4-rc8. With the new kernel, the display is horizontally mirrored and shows inverted colors.

I'm running a K&K Trizeps VII with a i.MX6 SoloX SoC. There's a 24-Bit RGB display connected to LCDIF 1 which is driven by this non-mainline panel driver: https://github.com/Tragetaschen/linux-stable-pconxs/blob/linux-p868-4.19.y/drivers/gpu/drm/panel/panel-ortustech-com32h3n89ulc.c

I have created a quick test image which is converted with convert color-test.png -depth 8 color-test.rgba and written directly to /dev/fb0 with dd if=color-test.rgba of=/dev/fb0 bs=1536000

The result is a display where the image is mirrored horizontally and all colors are inverted.

changed the description

This was due to a fix in the bitbanging GPIO SPI driver that resulted in the clock being inverted and thus wrongly configuring the display.

closed

mentioned in commit 4be9075f

mentioned in commit lyudess/linux@1c7b17cf