From 07ee2d3bf91832cb3286898fba9155665a390a79 Mon Sep 17 00:00:00 2001
From: Tim Gover <tim.gover@raspberrypi.com>
Date: Thu, 31 Oct 2024 16:12:54 +0000
Subject: [PATCH] dtoverlay: Add a dtoverlay for pwm-gpio

Signed-off-by: Tim Gover <tim.gover@raspberrypi.com>
---
 arch/arm/boot/dts/overlays/Makefile           |  1 +
 arch/arm/boot/dts/overlays/README             |  6 +++
 .../boot/dts/overlays/pwm-gpio-overlay.dts    | 38 +++++++++++++++++++
 3 files changed, 45 insertions(+)
 create mode 100644 arch/arm/boot/dts/overlays/pwm-gpio-overlay.dts

diff --git a/arch/arm/boot/dts/overlays/Makefile b/arch/arm/boot/dts/overlays/Makefile
index b9530c339797c6..6b60068b125c15 100644
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -217,6 +217,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	proto-codec.dtbo \
 	pwm.dtbo \
 	pwm-2chan.dtbo \
+	pwm-gpio.dtbo \
 	pwm-ir-tx.dtbo \
 	pwm1.dtbo \
 	qca7000.dtbo \
diff --git a/arch/arm/boot/dts/overlays/README b/arch/arm/boot/dts/overlays/README
index e1df8b1ba3c77e..5c6344eb6f9870 100644
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -3903,6 +3903,12 @@ Params: pin                     Output pin (default 18) - see table
         clock                   PWM clock frequency (informational)
 
 
+Name:   pwm-gpio
+Info:   Configures the software PWM GPIO driver
+Load:   dtoverlay=pwm-gpio,<param>=<val>
+Params: gpio                    Output pin (default 4)
+
+
 Name:   pwm-ir-tx
 Info:   Use GPIO pin as pwm-assisted infrared transmitter output.
         This is an alternative to "gpio-ir-tx". pwm-ir-tx makes use
diff --git a/arch/arm/boot/dts/overlays/pwm-gpio-overlay.dts b/arch/arm/boot/dts/overlays/pwm-gpio-overlay.dts
new file mode 100644
index 00000000000000..f5a1fb38e2578e
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/pwm-gpio-overlay.dts
@@ -0,0 +1,38 @@
+// Device tree overlay for software GPIO PWM.
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835";
+
+	fragment@0 {
+		target = <&gpio>;
+		__overlay__ {
+			pwm_gpio_pins: pwm_gpio_pins@4 {
+				brcm,pins = <4>; /* gpio 4 */
+				brcm,function = <1>; /* output */
+				brcm,pull = <0>; /* pull-none */
+			};
+		};
+	};
+
+	fragment@1 {
+		target-path = "/";
+		__overlay__ {
+			pwm_gpio: pwm_gpio@4 {
+				  compatible = "pwm-gpio";
+				  pinctrl-names = "default";
+				  pinctrl-0 = <&pwm_gpio_pins>;
+				  gpios = <&gpio 4 0>;
+			};
+		};
+	};
+
+	__overrides__ {
+		gpio = <&pwm_gpio>,"gpios:4",
+		       <&pwm_gpio_pins>,"brcm,pins:0",
+		       /* modify reg values to allow multiple instantiation */
+		       <&pwm_gpio>,"reg:0",
+		       <&pwm_gpio_pins>,"reg:0";
+	};
+};