linux-kernel - [PATCH v2] arm64: dts: mediatek: mt8188: Assign apll1 clock as parent to avoid hang

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Message-Id: <20250207-mt8188-afe-fix-hang-disabled-apll1-clk-v2-1-a636d844c272@collabora.com>
Date: Fri, 07 Feb 2025 14:41:24 -0300
From: Nícolas F. R. A. Prado <nfraprado@...labora.com>
To: Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, 
 Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>, 
 Matthias Brugger <matthias.bgg@...il.com>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Fei Shao <fshao@...omium.org>
Cc: kernel@...labora.com, linux-sound@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-mediatek@...ts.infradead.org, 
 Trevor Wu (吳文良) <Trevor.Wu@...iatek.com>, 
 Chen-Yu Tsai <wenst@...omium.org>, devicetree@...r.kernel.org, 
 stable@...r.kernel.org, 
 Nícolas F. R. A. Prado <nfraprado@...labora.com>
Subject: [PATCH v2] arm64: dts: mediatek: mt8188: Assign apll1 clock as
 parent to avoid hang

Certain registers in the AFE IO space require the apll1 clock to be
enabled in order to be read, otherwise the machine hangs (registers like
0x280, 0x410 (AFE_GAIN1_CON0) and 0x830 (AFE_CONN0_5)). During AFE
driver probe, when initializing the regmap for the AFE IO space those
registers are read, resulting in a hang during boot.

This has been observed on the Genio 700 EVK, Genio 510 EVK and
MT8188-Geralt-Ciri Chromebook, all of which are based on the MT8188 SoC.

Assign CLK_TOP_APLL1_D4 as the parent for CLK_TOP_A1SYS_HP, which is
enabled during register read and write, to make sure the apll1 is
enabled during register operations and prevent the MT8188 machines from
hanging during boot.

Cc: stable@...r.kernel.org
Fixes: 4dbec3a59a71 ("arm64: dts: mediatek: mt8188: Add audio support")
Suggested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
---
Changes in v2:
- Changed patch from explicitly enabling apll1 clock in the driver to
  assigning apll1_d4 as the parent for the a1sys_hp clock in the
  mt8188.dtsi
- Link to v1: https://lore.kernel.org/r/20241203-mt8188-afe-fix-hang-disabled-apll1-clk-v1-1-07cdd7760834@collabora.com
---
 arch/arm64/boot/dts/mediatek/mt8188.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/mediatek/mt8188.dtsi b/arch/arm64/boot/dts/mediatek/mt8188.dtsi
index 5d78f51c6183c15018986df2c76e6fdc1f9f43b4..6352c9bd436550dce66435f23653ebcb43ccf0cd 100644
--- a/arch/arm64/boot/dts/mediatek/mt8188.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8188.dtsi
@@ -1392,7 +1392,7 @@ afe: audio-controller@...10000 {
 			compatible = "mediatek,mt8188-afe";
 			reg = <0 0x10b10000 0 0x10000>;
 			assigned-clocks = <&topckgen CLK_TOP_A1SYS_HP>;
-			assigned-clock-parents =  <&clk26m>;
+			assigned-clock-parents = <&topckgen CLK_TOP_APLL1_D4>;
 			clocks = <&clk26m>,
 				 <&apmixedsys CLK_APMIXED_APLL1>,
 				 <&apmixedsys CLK_APMIXED_APLL2>,

---
base-commit: ed58d103e6da15a442ff87567898768dc3a66987
change-id: 20241203-mt8188-afe-fix-hang-disabled-apll1-clk-b3c11782cbaf

Best regards,
-- 
Nícolas F. R. A. Prado <nfraprado@...labora.com>