Thread (4 messages) 4 messages, 1 author, 4d ago
COOLING4d

[PATCH v2 2/3] powerpc/dts: pdm360ng: Convert ADS7845 touchscreen to DT bindings

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2026-07-20 05:37:25
Also in: linux-devicetree, lkml
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Michael Ellerman, Linus Torvalds

The PDM360NG board is equipped with an ADS7845 touchscreen controller.
Previously, pdm360ng.dts used "ti,ads7846" as a placeholder and relied
on platform data in pdm360ng.c to override the model to 7845.

Update the ts@0 touchscreen node in pdm360ng.dts to use the correct
"ti,ads7845" compatible string along with pendown-gpio (using
GPIO_ACTIVE_LOW) and interrupt-parent properties referencing gpio_pic.

Note that changing the compatible string to "ti,ads7845" causes the
legacy platform data notifier in pdm360ng.c to skip injecting platform
data, allowing ads7846 to parse DT properties natively. Although
pdm360ng_penirq_init() in pdm360ng.c still runs on boot prior to removing
pdm360ng.c, its direct GPIO register writes are harmless because the
gpio-mpc8xxx driver resets and re-unmasks pin 25 on demand when the
ads7846 driver requests its interrupt.

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 arch/powerpc/boot/dts/pdm360ng.dts | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/boot/dts/pdm360ng.dts b/arch/powerpc/boot/dts/pdm360ng.dts
index 67c3b9db75d7..05e93ca294ee 100644
--- a/arch/powerpc/boot/dts/pdm360ng.dts
+++ b/arch/powerpc/boot/dts/pdm360ng.dts
@@ -9,6 +9,7 @@
  * Copyright 2008 Freescale Semiconductor Inc.
  */
 
+#include <dt-bindings/gpio/gpio.h>
 #include "mpc5121.dtsi"
 
 / {
@@ -176,11 +177,12 @@ psc@11900 {
 
 			/* 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>;
+				interrupt-parent = <&gpio_pic>;
+				interrupts = <25 0x8>;
+				pendown-gpio = <&gpio_pic 25 GPIO_ACTIVE_LOW>;
 			};
 		};
 
-- 
2.55.0.229.g6434b31f56-goog

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