linux-kernel - [PATCH] ARM: dts: imx6qdl-wandboard: add scl/sda gpios definitions for i2c bus recovery

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Date:   Sun, 31 Jan 2021 13:54:25 +0300
From:   Dima Azarkin <azdmg@...dex.ru>
To:     Rob Herring <robh+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     Christian Hewitt <christianshewitt@...il.com>,
        Dima Azarkin <azdmg@...dex.ru>
Subject: [PATCH] ARM: dts: imx6qdl-wandboard: add scl/sda gpios definitions for i2c bus recovery

The i2c bus on imx6qdl-wandboard has intermittent issues where SDA can freeze
on low level at the end of transaction so the bus can no longer work. This
impacts reading of EDID data leading to incorrect TV resolution and no audio.

This scenario is improved by adding scl/sda gpios definitions to implement the
i2c bus recovery mechanism.

Signed-off-by: Dima Azarkin <azdmg@...dex.ru>
---
 arch/arm/boot/dts/imx6qdl-wandboard.dtsi | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/arch/arm/boot/dts/imx6qdl-wandboard.dtsi b/arch/arm/boot/dts/imx6qdl-wandboard.dtsi
index c070893c509e..b62a0dbb033f 100644
--- a/arch/arm/boot/dts/imx6qdl-wandboard.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-wandboard.dtsi
@@ -97,15 +97,21 @@
 
 &i2c1 {
 	clock-frequency = <100000>;
-	pinctrl-names = "default";
+	pinctrl-names = "default", "gpio";
 	pinctrl-0 = <&pinctrl_i2c1>;
+	pinctrl-1 = <&pinctrl_i2c1_gpio>;
+	scl-gpios = <&gpio3 21 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+	sda-gpios = <&gpio3 28 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 	status = "okay";
 };
 
 &i2c2 {
 	clock-frequency = <100000>;
-	pinctrl-names = "default";
+	pinctrl-names = "default", "gpio";
 	pinctrl-0 = <&pinctrl_i2c2>;
+	pinctrl-1 = <&pinctrl_i2c2_gpio>;
+	scl-gpios = <&gpio4 12 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+	sda-gpios = <&gpio4 13 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 	status = "okay";
 
 	codec: sgtl5000@a {
@@ -185,6 +191,13 @@
 			>;
 		};
 
+		pinctrl_i2c1_gpio: i2c1gpiogrp {
+			fsl,pins = <
+				MX6QDL_PAD_EIM_D21__GPIO3_IO21		0x4001b8b0
+				MX6QDL_PAD_EIM_D28__GPIO3_IO28		0x4001b8b0
+			>;
+		};
+
 		pinctrl_i2c2: i2c2grp {
 			fsl,pins = <
 				MX6QDL_PAD_KEY_COL3__I2C2_SCL		0x4001b8b1
@@ -192,6 +205,13 @@
 			>;
 		};
 
+		pinctrl_i2c2_gpio: i2c2gpiogrp {
+			fsl,pins = <
+				MX6QDL_PAD_KEY_COL3__GPIO4_IO12		0x4001b8b0
+				MX6QDL_PAD_KEY_ROW3__GPIO4_IO13		0x4001b8b0
+			>;
+		};
+
 		pinctrl_mclk: mclkgrp {
 			fsl,pins = <
 				MX6QDL_PAD_GPIO_0__CCM_CLKO1		0x130b0
-- 
2.17.1