[PATCH 11/13] ARM: dts: stm32: fix LTDC port node on STM32 MCU ad MPU
Alexandre TORGUE
alexandre.torgue at foss.st.com
Thu Apr 15 15:35:25 BST 2021
On 4/15/21 4:30 PM, Marek Vasut wrote:
> On 4/15/21 3:34 PM, Alexandre TORGUE wrote:
>> Hi Marek
>
> Hello Alexandre,
>
>>>> diff --git a/arch/arm/boot/dts/stm32mp157c-dk2.dts
>>>> b/arch/arm/boot/dts/stm32mp157c-dk2.dts
>>>> index 2bc92ef3aeb9..19ef475a48fc 100644
>>>> --- a/arch/arm/boot/dts/stm32mp157c-dk2.dts
>>>> +++ b/arch/arm/boot/dts/stm32mp157c-dk2.dts
>>>> @@ -82,9 +82,15 @@
>>>> };
>>>> <dc {
>>>> - status = "okay";
>>>> -
>>>> port {
>>>> + #address-cells = <1>;
>>>> + #size-cells = <0>;
>>>> +
>>>> + ltdc_ep0_out: endpoint at 0 {
>>>> + reg = <0>;
>>>> + remote-endpoint = <&sii9022_in>;
>>>> + };
>>>> +
>>>> ltdc_ep1_out: endpoint at 1 {
>>>> reg = <1>;
>>>> remote-endpoint = <&dsi_in>;
>>>
>>> [...]
>>>
>>>> diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-avenger96.dtsi
>>>> b/arch/arm/boot/dts/stm32mp15xx-dhcor-avenger96.dtsi
>>>> index 64dca5b7f748..e7f10975cacf 100644
>>>> --- a/arch/arm/boot/dts/stm32mp15xx-dhcor-avenger96.dtsi
>>>> +++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-avenger96.dtsi
>>>> @@ -277,11 +277,7 @@
>>>> status = "okay";
>>>> port {
>>>> - #address-cells = <1>;
>>>> - #size-cells = <0>;
>>>> -
>>>> - ltdc_ep0_out: endpoint at 0 {
>>>> - reg = <0>;
>>>> + ltdc_ep0_out: endpoint {
>>>> remote-endpoint = <&adv7513_in>;
>>>> };
>>>> };
>>>
>>> I think this is wrong, the AV96 can have two displays connected to
>>> two ports of the LTDC, just like DK2 for example.
>>
>> As for dk2 address/size cells are added only if there are 2 endpoints.
>> It is for this reason I moved endpoint0 definition from
>> stm32mp15xx-dkx to stm32mp151a-dk1.dts (dk1 has only one endpoint).
>>
>> Here it's the same, if you have second endpoint then adress/size will
>> have to be added.
>
> That's a bit problematic. Consider either the use case of DTO which adds
> the other display, or even a custom board DTS. Without your patch, this
> works:
>
> arch/arm/boot/dts/stm32mp15xx-dhcor-avenger96.dtsi
> <dc {
> ...
> ports {
> ltdc_ep0_out: endpoint at 0 {
> remote-endpoint = <&adv7513_in>;
> };
> };
> };
>
> board-with-display.dts or board-overlay.dts
> <dc {
> ports {
> endpoint at 1 { // just add another endpoint at 1, no problem
> remote-endpoint = <&display>;
> };
> };
> };
>
> With your patch, the DTS would have to modify the "endpoint" node to be
> "endpoint at 0" probably with a whole lot of /detele-node/ etc. magic (DTO
> cannot do that, so that's a problem, and I do use DTOs on AV96
> extensively for the various expansion cards) and then add the
> endpoint at 1. That becomes real complicated in custom board DT, and
> impossible with DTO.
Yes I agree that it'll be problematic. So maybe so solution would be to
not detect a warning for the initial case (only one endpoint with a reg)
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