Re: [PATCH 11/13] ARM: dts: stm32: fix LTDC port node on STM32 MCU ad MPU

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 4/15/21 4:35 PM, Alexandre TORGUE wrote:


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 @@
  };
  &ltdc {
-    status = "okay";
-
      port {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ltdc_ep0_out: endpoint@0 {
+            reg = <0>;
+            remote-endpoint = <&sii9022_in>;
+        };
+
          ltdc_ep1_out: endpoint@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@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
&ltdc {
   ...
   ports {
     ltdc_ep0_out: endpoint@0 {
       remote-endpoint = <&adv7513_in>;
     };
   };
};

board-with-display.dts or board-overlay.dts
&ltdc {
   ports {
     endpoint@1 { // just add another endpoint@1, no problem
       remote-endpoint = <&display>;
     };
   };
};

With your patch, the DTS would have to modify the "endpoint" node to be "endpoint@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@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)

That looks OK. Or even better, if the checker warned only on IPs which cannot have more than one endpoint, but have endpoint@N in DT (where N in 0..+inf) . On IPs which can have one or more endpoints, the warning should not be emitted.



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux