linux-kernel - Re: [PATCH v1 1/3] ARM: dts: imx6qdl-apalis: Do not rely on DDC I2C bus bitbang for HDMI

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Message-ID: <1474033114.3103.25.camel@toradex.com>
Date:   Fri, 16 Sep 2016 13:38:35 +0000
From:   Marcel Ziswiler <marcel.ziswiler@...adex.com>
To:     "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "maitysanchayan@...il.com" <maitysanchayan@...il.com>
CC:     "stefan@...er.ch" <stefan@...er.ch>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v1 1/3] ARM: dts: imx6qdl-apalis: Do not rely on DDC I2C
 bus bitbang for HDMI

On Wed, 2016-09-14 at 12:05 +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>
> ---
> Hello,
> 
> This patch is tested with the following patch applied
> https://patchwork.kernel.org/patch/9296883/
> 
> and is based on the suggestions from Vladimir
> https://lkml.org/lkml/2016/8/29/322
> 
> This and following two patches are based on top of shawn's
> for-next branch.
> 
> Regards,
> Sanchayan.
> ---
>  arch/arm/boot/dts/imx6q-apalis-ixora.dts |  6 ------
>  arch/arm/boot/dts/imx6qdl-apalis.dtsi    | 25 +++++++++-------------
> ---
>  2 files changed, 9 insertions(+), 22 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> index 207b85b..d99979e 100644
> --- a/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> +++ b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> @@ -55,7 +55,6 @@
>  		     "fsl,imx6q";
>  
>  	aliases {
> -		i2c0 = &i2cddc;
>  		i2c1 = &i2c1;
>  		i2c2 = &i2c2;
>  		i2c3 = &i2c3;

I would suggest rising them up in rank.

> @@ -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
>  		>;
>  	};
 
Rest looks fine and tested working fine on top of 4.8.0-rc6-next-20160916.