linux-kernel - [PATCH AUTOSEL 5.18 26/49] arm64: dts: qcom: sc7280-qcard: Configure CTS pin to bias-bus-hold for bluetooth

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Message-Id: <20220601135214.2002647-26-sashal@kernel.org>
Date:   Wed,  1 Jun 2022 09:51:50 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>,
        Douglas Anderson <dianders@...omium.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Sasha Levin <sashal@...nel.org>, agross@...nel.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org
Subject: [PATCH AUTOSEL 5.18 26/49] arm64: dts: qcom: sc7280-qcard: Configure CTS pin to bias-bus-hold for bluetooth

From: Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>

[ Upstream commit 3d0e375bae55c2dfa6dd0762f45ad71f0b192f71 ]

WLAN rail was leaking power during RBSC/sleep even after turning BT off.
Change active and sleep pinctrl configurations to handle same.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
Reviewed-by: Douglas Anderson <dianders@...omium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
Link: https://lore.kernel.org/r/1650556567-4995-3-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi b/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi
index b833ba1e8f4a..98b5cd70bca5 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi
@@ -398,8 +398,14 @@ &qup_i2c13_data_clk {
 
 /* For mos_bt_uart */
 &qup_uart7_cts {
-	/* Configure a pull-down on CTS to match the pull of the Bluetooth module. */
-	bias-pull-down;
+	/*
+	 * Configure a bias-bus-hold on CTS to lower power
+	 * usage when Bluetooth is turned off. Bus hold will
+	 * maintain a low power state regardless of whether
+	 * the Bluetooth module drives the pin in either
+	 * direction or leaves the pin fully unpowered.
+	 */
+	bias-bus-hold;
 };
 
 /* For mos_bt_uart */
@@ -490,10 +496,13 @@ qup_uart7_sleep_cts: qup-uart7-sleep-cts {
 		pins = "gpio28";
 		function = "gpio";
 		/*
-		 * Configure a pull-down on CTS to match the pull of
-		 * the Bluetooth module.
+		 * Configure a bias-bus-hold on CTS to lower power
+		 * usage when Bluetooth is turned off. Bus hold will
+		 * maintain a low power state regardless of whether
+		 * the Bluetooth module drives the pin in either
+		 * direction or leaves the pin fully unpowered.
 		 */
-		bias-pull-down;
+		bias-bus-hold;
 	};
 
 	/* For mos_bt_uart */
-- 
2.35.1