linux-kernel - Re: [PATCH v2 1/3] ARM: dts: imx6qdl-apalis: Do not rely on DDC I2C bus bitbang for HDMI

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Message-ID: <20161022032559.GL30578@tiger>
Date:   Sat, 22 Oct 2016 11:25:59 +0800
From:   Shawn Guo <shawnguo@...nel.org>
To:     Sanchayan Maity <maitysanchayan@...il.com>
Cc:     marcel.ziswiler@...adex.com, stefan@...er.ch,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] ARM: dts: imx6qdl-apalis: Do not rely on DDC I2C
 bus bitbang for HDMI

On Mon, Sep 19, 2016 at 10:41:51AM +0530, Sanchayan Maity wrote:
> Remove the use of DDC I2C bus bitbang to support reading of EDID
> and rely on support from internal HDMI I2C master controller instead.
> As a result remove the device tree property ddc-i2c-bus.
> 
> Signed-off-by: Sanchayan Maity <maitysanchayan@...il.com>

I think that the dw-hdmi i2c support [1] is a prerequisite of this
patch.  I do not see it lands on v4.9-rc1.  Or am I missing something?

Shawn

[1] https://patchwork.kernel.org/patch/9296883/

> ---
> Changes since v1:
> 
> Change the ranking in i2c aliases
> 
> v1: https://lkml.org/lkml/2016/9/14/55
> ---
>  arch/arm/boot/dts/imx6q-apalis-ixora.dts | 12 +++---------
>  arch/arm/boot/dts/imx6qdl-apalis.dtsi    | 25 +++++++++----------------
>  2 files changed, 12 insertions(+), 25 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/imx6q-apalis-ixora.dts b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> index 207b85b..82b81e0 100644
> --- a/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> +++ b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> @@ -55,10 +55,9 @@
>  		     "fsl,imx6q";
>  
>  	aliases {
> -		i2c0 = &i2cddc;
> -		i2c1 = &i2c1;
> -		i2c2 = &i2c2;
> -		i2c3 = &i2c3;
> +		i2c0 = &i2c1;
> +		i2c1 = &i2c2;
> +		i2c2 = &i2c3;
>  	};
>  
>  	aliases {
> @@ -186,11 +185,6 @@
>  };
>  
>  &hdmi {
> -	ddc-i2c-bus = <&i2cddc>;
> -	status = "okay";
> -};
> -
> -&i2cddc {
>  	status = "okay";
>  };
>  
> diff --git a/arch/arm/boot/dts/imx6qdl-apalis.dtsi b/arch/arm/boot/dts/imx6qdl-apalis.dtsi
> index 99e323b..8c67dd8 100644
> --- a/arch/arm/boot/dts/imx6qdl-apalis.dtsi
> +++ b/arch/arm/boot/dts/imx6qdl-apalis.dtsi
> @@ -53,18 +53,6 @@
>  		status = "disabled";
>  	};
>  
> -	/* DDC_I2C: I2C2_SDA/SCL on MXM3 205/207 */
> -	i2cddc: i2c@0 {
> -		compatible = "i2c-gpio";
> -		pinctrl-names = "default";
> -		pinctrl-0 = <&pinctrl_i2c_ddc>;
> -		gpios = <&gpio3 16 GPIO_ACTIVE_HIGH /* sda */
> -			 &gpio2 30 GPIO_ACTIVE_HIGH /* scl */
> -			>;
> -		i2c-gpio,delay-us = <2>;	/* ~100 kHz */
> -		status = "disabled";
> -	};
> -
>  	reg_1p8v: regulator-1p8v {
>  		compatible = "regulator-fixed";
>  		regulator-name = "1P8V";
> @@ -209,6 +197,12 @@
>  	};
>  };
>  
> +&hdmi {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&pinctrl_hdmi_ddc>;
> +	status = "disabled";
> +};
> +
>  /*
>   * GEN1_I2C: I2C1_SDA/SCL on MXM3 209/211 (e.g. RTC on carrier
>   * board)
> @@ -633,11 +627,10 @@
>  		>;
>  	};
>  
> -	pinctrl_i2c_ddc: gpioi2cddcgrp {
> +	pinctrl_hdmi_ddc: hdmiddcgrp {
>  		fsl,pins = <
> -			/* DDC bitbang */
> -			MX6QDL_PAD_EIM_EB2__GPIO2_IO30 0x1b0b0
> -			MX6QDL_PAD_EIM_D16__GPIO3_IO16 0x1b0b0
> +			MX6QDL_PAD_EIM_EB2__HDMI_TX_DDC_SCL 0x4001b8b1
> +			MX6QDL_PAD_EIM_D16__HDMI_TX_DDC_SDA 0x4001b8b1
>  		>;
>  	};
>  
> -- 
> 2.9.3
>