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

[Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxx
Fixes: 4dbec3a59a71 ("arm64: dts: mediatek: mt8188: Add audio support")
Suggested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxx
---
 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@10b10000 {
 			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@xxxxxxxxxxxxx>