From d7a810374597774f0e01eedfc30074772f4e9f85 Mon Sep 17 00:00:00 2001
From: Christoph <c.orth@ugreen.eu>
Date: Wed, 28 Apr 2021 20:30:44 +0200
Subject: [PATCH] overlays: Add ugreen-dabboard overlay

This is a simple overlay based on the simple-audio-card and the dmic
codec. It has the speciality that it is configured to use the codec
as a master I2S device. It works for example with the Si468x DAB
receiver on the uGreen DABBoard.

See: https://github.com/raspberrypi/linux/issues/4304

Signed-off-by: Christoph Orth <c.orth@ugreen.eu>
---
 arch/arm/boot/dts/overlays/Makefile           |  1 +
 arch/arm/boot/dts/overlays/README             | 10 ++++
 .../dts/overlays/ugreen-dabboard-overlay.dts  | 49 +++++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 arch/arm/boot/dts/overlays/ugreen-dabboard-overlay.dts

--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -209,6 +209,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	uart4.dtbo \
 	uart5.dtbo \
 	udrc.dtbo \
+	ugreen-dabboard.dtbo \
 	upstream.dtbo \
 	upstream-pi4.dtbo \
 	vc4-fkms-v3d.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -3130,6 +3130,16 @@ Load:   dtoverlay=udrc,<param>=<val>
 Params: alsaname                Name of the ALSA audio device (default "udrc")
 
 
+Name:   ugreen-dabboard
+Info:   Configures the ugreen-dabboard I2S overlay
+        This is a simple overlay based on the simple-audio-card and the dmic
+        codec. It has the speciality that it is configured to use the codec
+        as a master I2S device. It works for example with the Si468x DAB
+        receiver on the uGreen DABBoard.
+Load:   dtoverlay=ugreen-dabboard,<param>=<val>
+Params: card-name               Override the default, "dabboard", card name.
+
+
 Name:   upstream
 Info:   Allow usage of downstream .dtb with upstream kernel. Comprises the
         vc4-kms-v3d and dwc2 overlays.
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/ugreen-dabboard-overlay.dts
@@ -0,0 +1,49 @@
+// Definitions for the ugreen dabboard I2S
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835";
+
+	fragment@0 {
+		target = <&i2s>;
+		__overlay__ {
+			status = "okay";
+		};
+	};
+
+	fragment@1 {
+		target-path = "/";
+		__overlay__ {
+			dmic_codec: dmic-codec {
+				#sound-dai-cells = <0>;
+				compatible = "dmic-codec";
+				status = "okay";
+			};
+		};
+	};
+
+	fragment@2 {
+		target = <&sound>;
+		sound_overlay: __overlay__ {
+			compatible = "simple-audio-card";
+			simple-audio-card,format = "i2s";
+			simple-audio-card,name = "dabboard";
+			simple-audio-card,bitclock-master = <&dailink0_slave>;
+			simple-audio-card,frame-master = <&dailink0_slave>;
+			simple-audio-card,widgets = "Microphone", "Microphone Jack";
+			status = "okay";
+			simple-audio-card,cpu {
+				sound-dai = <&i2s>;
+			};
+			dailink0_slave: simple-audio-card,codec {
+				#sound-dai-cells = <0>;
+				sound-dai = <&dmic_codec>;
+			};
+		};
+	};
+
+	__overrides__ {
+		card-name = <&sound_overlay>,"simple-audio-card,name";
+	};
+};