linux-kernel - [PATCH 2/2] arm64: dts: qcom: x1e80100-crd: Drop duplicate DMIC supplies

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Message-Id: <20241203-x1e80100-va-mic-bias-v1-2-0dfd4d9b492c@linaro.org>
Date: Tue, 03 Dec 2024 18:44:03 +0100
From: Stephan Gerhold <stephan.gerhold@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>
Cc: Rob Herring <robh@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
 Srinivas Kandagatla <srinivas.kandagatla@...aro.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>, 
 linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Abel Vesa <abel.vesa@...aro.org>, 
 Johan Hovold <johan@...nel.org>
Subject: [PATCH 2/2] arm64: dts: qcom: x1e80100-crd: Drop duplicate DMIC
 supplies

The WCD938x codec provides two controls for each of the MIC_BIASn outputs:

 - "MIC BIASn" enables an internal regulator to generate the output
   with a configurable voltage (qcom,micbiasN-microvolt).

 - "VA MIC BIASn" enables "pull-up mode" that bypasses the internal
   regulator and directly outputs fixed 1.8V from the VDD_PX pin.
   This is intended for low-power VA (voice activation) use cases.

The audio-routing setup for the X1E80100 CRD currently specifies both
as power supplies for the DMICs, but only one of them can be active
at the same time. In practice, only the internal regulator is used
with the current setup because the driver prefers it over pull-up mode.

Make this more clear by dropping the redundant routes to the pull-up
"VA MIC BIASn" supply. There is no functional difference except that we
skip briefly switching to pull-up mode when shutting down the microphone.

Fixes: 4442a67eedc1 ("arm64: dts: qcom: x1e80100-crd: add sound card")
Signed-off-by: Stephan Gerhold <stephan.gerhold@...aro.org>
---
 arch/arm64/boot/dts/qcom/x1e80100-crd.dts | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/x1e80100-crd.dts b/arch/arm64/boot/dts/qcom/x1e80100-crd.dts
index 39f9d9cdc10d8e79824b72288e2529536144fa9e..a4d8da81bb4468e03ba8a9d37efaae10f7a6b53e 100644
--- a/arch/arm64/boot/dts/qcom/x1e80100-crd.dts
+++ b/arch/arm64/boot/dts/qcom/x1e80100-crd.dts
@@ -188,10 +188,6 @@ sound {
 				"VA DMIC1", "MIC BIAS3",
 				"VA DMIC2", "MIC BIAS1",
 				"VA DMIC3", "MIC BIAS1",
-				"VA DMIC0", "VA MIC BIAS3",
-				"VA DMIC1", "VA MIC BIAS3",
-				"VA DMIC2", "VA MIC BIAS1",
-				"VA DMIC3", "VA MIC BIAS1",
 				"TX SWR_INPUT1", "ADC2_OUTPUT";
 
 		wcd-playback-dai-link {

-- 
2.47.0