From b40d412787cf6e47a9acb632da22a2ca7d99a483 Mon Sep 17 00:00:00 2001
From: Lorenzo Stoakes <ljs@kernel.org>
Date: Wed, 19 Aug 2026 17:27:29 +0100
Subject: [PATCH] arm64: dts: apple: t8112-j493: Enable SIO for DP audio

On bootup, an Apple MacBook Pro (13-inch, M2, 2022) dmesg shows:

	dcp-dp-audio 238334000.audio-controller: No DMA device

And:

	$ cat /proc/device-tree/soc/sio@236400000/status
	disabled

This model's t8112-j493 hardware is able to encode this data through its
SIO coprocessor, but the device tree doesn't configure it to be able to.

Similar to t8112-j473, enable the node and assign the sio alias so m1n1
injects the correct firmware.

With this applied the sink is available:

	 ~ cat /proc/asound/cards
	 0 [DisplayPort    ]: apple_dcp - Apple DisplayPort
	                      Apple DisplayPort
	...

And audio works correctly over DP and is stable.

Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
---
 arch/arm64/boot/dts/apple/t8112-j493.dts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/apple/t8112-j493.dts b/arch/arm64/boot/dts/apple/t8112-j493.dts
index 8ec34e61f48432..3c316f0c97c3d0 100644
--- a/arch/arm64/boot/dts/apple/t8112-j493.dts
+++ b/arch/arm64/boot/dts/apple/t8112-j493.dts
@@ -27,6 +27,7 @@
 	aliases {
 		bluetooth0 = &bluetooth0;
 		keyboard = &keyboard;
+		sio = &sio;
 		touchbar0 = &touchbar0;
 		wifi0 = &wifi0;
 	};
@@ -333,5 +334,10 @@
 	status = "okay";
 };
 
+/* remove once m1n1 enables sio nodes after setup */
+&sio {
+	status = "okay";
+};
+
 #include "hwmon-fan.dtsi"
 #include "hwmon-laptop.dtsi"