linux-kernel - [PATCH 1/2] TSD: arm64: dts: rockchip: use codec as clock master

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Message-Id: <20230823122000.585787-1-jakob.unterwurzacher@theobroma-systems.com>
Date:   Wed, 23 Aug 2023 14:19:59 +0200
From:   Jakob Unterwurzacher <jakobunt@...il.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Heiko Stuebner <heiko@...ech.de>
Cc:     jakob.unterwurzacher@...obroma-systems.com,
        Ermin Sunj <ermin.sunj@...obroma-systems.com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] TSD: arm64: dts: rockchip: use codec as clock master

From: Ermin Sunj <ermin.sunj@...obroma-systems.com>

If the codec is not the clock master, the MCLK needs to be
synchronous to both I2S_SCL ans I2S_LRCLK. We do not have that
on Haikou, causing distorted audio.

Before:

 Running audioloopback.py script on Ringneck, 1kHz
 output sine wave is not stable and shows distortion.

After:

 10h stress tests audioloopback.py failed only one time.
 That is 0.00014% failure rate.

Signed-off-by: Ermin Sunj <ermin.sunj@...obroma-systems.com>
---
 arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
index 3a447d03e2a8..dafeef0c2dab 100644
--- a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
+++ b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
@@ -68,8 +68,10 @@ i2s0-sound {
 		simple-audio-card,format = "i2s";
 		simple-audio-card,name = "Haikou,I2S-codec";
 		simple-audio-card,mclk-fs = <512>;
+		simple-audio-card,frame-master = <&sgtl5000_codec>;
+		simple-audio-card,bitclock-master = <&sgtl5000_codec>;
 
-		simple-audio-card,codec {
+		sgtl5000_codec: simple-audio-card,codec {
 			clocks = <&sgtl5000_clk>;
 			sound-dai = <&sgtl5000>;
 		};
-- 
2.39.2