rk3568-pinctrl for LCD RGB666/RGB656

[Michael Riesch]

Hi Andy,

Thanks a lot for providing the pin mappings.

On 6/2/22 03:38, Andy Yan wrote:
> Hi Michael:
> 
> On 5/27/22 20:46, Michael Riesch wrote:
>> 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?

Just for clarification: Can the data pins which are not used by the LCD
in the respective operating mode be configured independently to their
alternative function? For example, can the pins D16 and D17 be used as
GPIOs or UART4_{TX,RX} in RGB666 mode?

If yes, it would probably make sense to reflect this in the
rk3568-pinctrl.dtsi by adding different groups of data pins.

>> 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?
> 
> 
> For 18-bit(RGB666),
> 
> R0~R5 map to D18~D23
> 
> G0~G5 map to D10~D15
> 
> B0~B5 map to D2~D7
> 
> 
> for 16-bit(RGB565)
> 
> R0~R4 map to D17~D23

D17 -> D19, right?

Thanks and best regards,
Michael

> 
> G0~G5 map to D10~D15
> 
> B0~B4 map to D3~D7
> 
>> Thanks and regards,
>> Michael
>>
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