Re: [PATCH 1/2] ARM: dts: exynos: arndale: use i2c-gpio for HDMI-DDC

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...

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