rk3568-pinctrl for LCD RGB666/RGB656

[Michael Riesch]

Hello Liang,

According to the RK3568 TRM the Video Output Processor (VOP2) is able to
emit parallel RGB data to LCDs in 24-bit (888), 18-bit (666) and 16-bit
(565) format. Based on this I would have expected that
rk3568-pinctrl.dtsi specifies one group of control pins (clock, hsync,
vsync, data enable) and three groups of data pins (with 24, 18, 16 pins,
respectively). Does this sound reasonable?

However, there is only one group with the control pins and the data pins
D0 - D23. I cannot tell which pins have to be assigned to the different
groups. They are mapped 1:1 to Rockchip pin names (e.g., D0 is mapped to
GPIO2_PD0) but it is not clear which function (channel, bit) each pin
has in this context. Could you please elaborate on the mapping of the D0
- D23 pins in the different operating modes?

Thanks and regards,
Michael