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

[Krzysztof Kozlowski]

On 26 July 2018 at 12:12, Andrzej Hajda <a.hajda at 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 at 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
>