Re: [PATCH v4 4/4] arm64: dts: imx8mn: Add ifm VHIP4 EvalBoard v1 and v2

On 1/6/26 3:37 PM, Peng Fan wrote:

Hello Peng,

Sorry for jumping in at V4.

Thank you for the review.

On Tue, Dec 30, 2025 at 10:32:34PM +0100, Marek Vasut wrote:

quoted

From: Fedor Ross <redacted>

...

quoted

+
+&ecspi1 {
+	pinctrl-names = "default", "cs";
+	pinctrl-0 = <&pinctrl_ecspi1>;
+	pinctrl-1 = <&pinctrl_ecspi1_cs>;

Not get the point of using a separate pinctrl for "cs",
I not see driver using it, or I may miss someting.

That's a good find, I believe it should be this way, because the 
pinctrl_ecspi1 is common and pinctrl_ecspi1_cs differs between v1 and v2 
boards. I'll include this in V5, I hope that looks better ?

  &ecspi1 {
-	pinctrl-names = "default", "cs";
-	pinctrl-0 = <&pinctrl_ecspi1>;
-	pinctrl-1 = <&pinctrl_ecspi1_cs>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_ecspi1>, <&pinctrl_ecspi1_cs>;
  	/delete-property/ dmas;
  	/delete-property/ dma-names;
  };

  &ecspi3 {
-	pinctrl-names = "default", "cs";
-	pinctrl-0 = <&pinctrl_ecspi3>;
-	pinctrl-1 = <&pinctrl_ecspi3_cs>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_ecspi3>, <&pinctrl_ecspi3_cs>;
  	/delete-property/ dmas;
  	/delete-property/ dma-names;
  };

quoted

+	/delete-property/ dmas;
+	/delete-property/ dma-names;

Why disable DMA here?

The devices on this SPI bus are slow and do only short register IO, so 
setting up a DMA for that would make the register IO slower, hence PIO only.