rk3568-pinctrl for LCD RGB666/RGB656

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

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

Re: rk3568-pinctrl for LCD RGB666/RGB656

[Andy Yan]

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?
>
> 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

G0~G5 map to D10~D15

B0~B4 map to D3~D7

> Thanks and regards,
> Michael
>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

Re: 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
>>
>> _______________________________________________
>> Linux-rockchip mailing list
>> Linux-rockchip@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-rockchip

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

Re: rk3568-pinctrl for LCD RGB666/RGB656

[Andy Yan]

Hi Michael:

On 6/2/22 14:41, Michael Riesch wrote:
> 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.


Yes, it is possible, you can do that.

>
>>> 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
>>>
>>> _______________________________________________
>>> Linux-rockchip mailing list
>>> Linux-rockchip@lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-rockchip

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

Re: rk3568-pinctrl for LCD RGB666/RGB656

[Michael Riesch]

Hi Andy,

On 6/2/22 12:53, Andy Yan wrote:
> [...]
>>>> 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.
> 
> 
> Yes, it is possible, you can do that.

Thanks for the clarification. I'll spin a patch some time after the
merge window.

Thanks and regards,
Michael

> [...]

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip