On 26.07.2018 12:23, Krzysztof Kozlowski wrote:
On 26 July 2018 at 12:12, Andrzej Hajda a.hajda@samsung.com wrote:
HDMI-DDC for unknown reasons doesn't work with Exynos I2C controllers. Fortunately i2c-gpio comes to the rescue.
Wait... what? The I2C controller on SoC (or its driver) is buggy in some way and we need to use these pins as GPIO to run i2c-gpio driver there? It looks like workaround not a proper solution...
But at least working one :) Better solutions are welcome. This seems to be not uncommon issue, if you for example look into odroid vendor kernel you can even find hardcoded EDIDs :)
Regards Andrzej
Best regards, Krzysztof
Signed-off-by: Andrzej Hajda a.hajda@samsung.com
arch/arm/boot/dts/exynos5250-arndale.dts | 24 +++++++++++++++-------- arch/arm/boot/dts/exynos5250-pinctrl.dtsi | 6 ++++++ 2 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/arch/arm/boot/dts/exynos5250-arndale.dts b/arch/arm/boot/dts/exynos5250-arndale.dts index 816d89d4cefd..591023391f7d 100644 --- a/arch/arm/boot/dts/exynos5250-arndale.dts +++ b/arch/arm/boot/dts/exynos5250-arndale.dts @@ -211,7 +211,7 @@
&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>;@@ -513,13 +513,6 @@ }; };
-&i2c_2 {
status = "okay";/* used by HDMI DDC */samsung,i2c-sda-delay = <100>;samsung,i2c-max-bus-freq = <66000>;-};
&i2c_3 { status = "okay";
@@ -608,3 +601,18 @@ status = "okay"; samsung,exynos-sataphy-i2c-phandle = <&sata_phy_i2c>; };
+&soc {
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 6ff6dea29d44..b25d520393b8 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>;-- 2.18.0
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