linux-kernel - pdm360ng and touchscreen set up

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Date: Mon, 1 Jul 2024 17:17:50 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Anatolij Gustschin <agust@...x.de>,
	Michael Ellerman <mpe@...erman.id.au>
Cc: linuxppc-dev@...abs.org, linux-kernel@...r.kernel.org
Subject: pdm360ng and touchscreen set up

Hi Anatolij, Michael,

I hope you can shed some light for me: why does pdm360ng have very
elaborate set up for the "pendown" GPIO of the touchscreen? Can we
simply fix the DTS in arch/powerpc/boot/dts/pdm360ng.dts and specify
correct pendown GPIO there, as well as correct interrupt trigger,
and remove most of arch/powerpc/platforms/512x/pdm360ng.c ?

Something like this:

diff --git a/arch/powerpc/boot/dts/pdm360ng.dts b/arch/powerpc/boot/dts/pdm360ng.dts
index 67c3b9db75d7..5651bd9d9db3 100644
--- a/arch/powerpc/boot/dts/pdm360ng.dts
+++ b/arch/powerpc/boot/dts/pdm360ng.dts
@@ -176,11 +176,12 @@ psc@...00 {

 			/* ADS7845 touch screen controller */
 			ts@0 {
-				compatible = "ti,ads7846";
+				compatible = "ti,ads7845";
 				reg = <0x0>;
 				spi-max-frequency = <3000000>;
 				/* pen irq is GPIO25 */
-				interrupts = <78 0x8>;
+				interrupts = <78 IRQ_TYPE_LEVEL_LOW>;
+				pendown-gpios = <&gpio 25 GPIO_ACTIVE_LOW>;
 			};
 		};

The reason I'm asking is that I want to remove support for platform
data in ads7846 driver and pdm360ng is one of the last 3 users of it in
the kernel.

Thanks.

-- 
Dmitry