From 8529728f25d620d82c118bd683fcd7bcf2b18ac5 Mon Sep 17 00:00:00 2001
From: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Date: Mon, 21 Oct 2019 09:19:21 -0700
Subject: [PATCH] arm64: dts: qcom: msm8998: Fixup uart3 gpio config for
 bluetooth

It turns out that the wcn3990 can float the gpio lines during bootup, etc
which will result in the uart core thinking there is incoming data.  This
results in the bluetooth stack getting garbage.  By applying a bias to
match what wcn3990 would drive, the issue is corrected.

Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Link: https://lore.kernel.org/r/20191021161921.31825-1-jeffrey.l.hugo@gmail.com
[bjorn: Moved board specific pinctrl states to the end]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 .../boot/dts/qcom/msm8998-clamshell.dtsi      | 23 +++++++++++++++++
 arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi     | 23 +++++++++++++++++
 arch/arm64/boot/dts/qcom/msm8998-pins.dtsi    | 25 ++++++++++++++++---
 3 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi b/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi
index 0f84fa0894a4..b3cf263f4a00 100644
--- a/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi
@@ -301,3 +301,26 @@
 	vdd-1.3-rfa-supply = <&vreg_l17a_1p3>;
 	vdd-3.3-ch0-supply = <&vreg_l25a_3p3>;
 };
+
+/* PINCTRL - board-specific pinctrl */
+&blsp1_uart3_on {
+	rx {
+		/delete-property/ bias-disable;
+		/*
+		 * Configure a pull-up on 45 (RX). This is needed to
+		 * avoid garbage data when the TX pin of the Bluetooth
+		 * module is in tri-state (module powered off or not
+		 * driving the signal yet).
+		 */
+		bias-pull-up;
+	};
+
+	cts {
+		/delete-property/ bias-disable;
+		/*
+		 * Configure a pull-down on 47 (CTS) to match the pull
+		 * of the Bluetooth module.
+		 */
+		bias-pull-down;
+	};
+};
diff --git a/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi b/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi
index 1220756fb5b3..6835fbd9636e 100644
--- a/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi
@@ -373,3 +373,26 @@
 	vdd-1.3-rfa-supply = <&vreg_l17a_1p3>;
 	vdd-3.3-ch0-supply = <&vreg_l25a_3p3>;
 };
+
+/* PINCTRL - board-specific pinctrl */
+&blsp1_uart3_on {
+	rx {
+		/delete-property/ bias-disable;
+		/*
+		 * Configure a pull-up on 45 (RX). This is needed to
+		 * avoid garbage data when the TX pin of the Bluetooth
+		 * module is in tri-state (module powered off or not
+		 * driving the signal yet).
+		 */
+		bias-pull-up;
+	};
+
+	cts {
+		/delete-property/ bias-disable;
+		/*
+		 * Configure a pull-down on 47 (CTS) to match the pull
+		 * of the Bluetooth module.
+		 */
+		bias-pull-down;
+	};
+};
diff --git a/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi b/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi
index e32d3ab395ea..7c222cbf19d9 100644
--- a/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi
@@ -77,13 +77,30 @@
 	};
 
 	blsp1_uart3_on: blsp1_uart3_on {
-		mux {
-			pins = "gpio45", "gpio46", "gpio47", "gpio48";
+		tx {
+			pins = "gpio45";
 			function = "blsp_uart3_a";
+			drive-strength = <2>;
+			bias-disable;
 		};
 
-		config {
-			pins = "gpio45", "gpio46", "gpio47", "gpio48";
+		rx {
+			pins = "gpio46";
+			function = "blsp_uart3_a";
+			drive-strength = <2>;
+			bias-disable;
+		};
+
+		cts {
+			pins = "gpio47";
+			function = "blsp_uart3_a";
+			drive-strength = <2>;
+			bias-disable;
+		};
+
+		rfr {
+			pins = "gpio48";
+			function = "blsp_uart3_a";
 			drive-strength = <2>;
 			bias-disable;
 		};