linux-kernel - [PATCH AUTOSEL 4.19 040/205] ARM: dts: exynos: Use i2c-gpio for HDMI-DDC on Arndale

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Date:   Fri,  8 Nov 2019 06:35:07 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Andrzej Hajda <a.hajda@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Sasha Levin <sashal@...nel.org>, devicetree@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 040/205] ARM: dts: exynos: Use i2c-gpio for HDMI-DDC on Arndale

From: Andrzej Hajda <a.hajda@...sung.com>

[ Upstream commit 620375c8fdf2f9f5110ed48d6c407cc4b7554f86 ]

HDMI-DDC for unknown reasons doesn't work with Exynos I2C controllers.
Fortunately i2c-gpio comes to the rescue.

Signed-off-by: Andrzej Hajda <a.hajda@...sung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/arm/boot/dts/exynos5250-arndale.dts  | 28 ++++++++++++++++-------
 arch/arm/boot/dts/exynos5250-pinctrl.dtsi |  6 +++++
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/arch/arm/boot/dts/exynos5250-arndale.dts b/arch/arm/boot/dts/exynos5250-arndale.dts
index 7a8a5c55701a8..bb3fcd652b5d7 100644
--- a/arch/arm/boot/dts/exynos5250-arndale.dts
+++ b/arch/arm/boot/dts/exynos5250-arndale.dts
@@ -150,7 +150,7 @@
 
 &hdmi {
 	status = "okay";
-	ddc = <&i2c_2>;
+	ddc = <&i2c_ddc>;
 	hpd-gpios = <&gpx3 7 GPIO_ACTIVE_LOW>;
 	vdd_osc-supply = <&ldo10_reg>;
 	vdd_pll-supply = <&ldo8_reg>;
@@ -452,13 +452,6 @@
 	};
 };
 
-&i2c_2 {
-	status = "okay";
-	/* used by HDMI DDC */
-	samsung,i2c-sda-delay = <100>;
-	samsung,i2c-max-bus-freq = <66000>;
-};
-
 &i2c_3 {
 	status = "okay";
 
@@ -547,3 +540,22 @@
 	status = "okay";
 	samsung,exynos-sataphy-i2c-phandle = <&sata_phy_i2c>;
 };
+
+&soc {
+	/*
+	 * For unknown reasons HDMI-DDC does not work with Exynos I2C
+	 * controllers. Lets use software I2C over GPIO pins as a workaround.
+	 */
+	i2c_ddc: i2c-gpio {
+		pinctrl-names = "default";
+		pinctrl-0 = <&i2c2_gpio_bus>;
+		status = "okay";
+		compatible = "i2c-gpio";
+		gpios = <&gpa0 6 0 /* sda */
+			 &gpa0 7 0 /* scl */
+			>;
+		i2c-gpio,delay-us = <2>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+};
diff --git a/arch/arm/boot/dts/exynos5250-pinctrl.dtsi b/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
index 6ff6dea29d449..b25d520393b8b 100644
--- a/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
+++ b/arch/arm/boot/dts/exynos5250-pinctrl.dtsi
@@ -225,6 +225,12 @@
 		samsung,pin-drv = <EXYNOS4_PIN_DRV_LV1>;
 	};
 
+	i2c2_gpio_bus: i2c2-gpio-bus {
+		samsung,pins = "gpa0-6", "gpa0-7";
+		samsung,pin-pud = <EXYNOS_PIN_PULL_NONE>;
+		samsung,pin-drv = <EXYNOS4_PIN_DRV_LV1>;
+	};
+
 	uart2_data: uart2-data {
 		samsung,pins = "gpa1-0", "gpa1-1";
 		samsung,pin-function = <EXYNOS_PIN_FUNC_2>;
-- 
2.20.1