[PATCH v2 2/2] arm: mvebu: x240: Use i2c-gpio instead of built in controller

[Stefan Roese]

On 7/26/23 01:13, Chris Packham wrote:
> There is an Errata with the built-in I2C controller where various I2C
> hardware errors cause a complete lockup of the CPU (which eventually
> results in an watchdog reset).
> 
> Put the I2C MPP pins into GPIO mode and use the i2c-gpio driver instead.
> This uses a bit-banged implementation of an I2C controller and avoids
> triggering the Errata.
> 
> Signed-off-by: Chris Packham <judge.packham at gmail.com>
> Reviewed-by: Stefan Roese <sr at denx.de>

Applied to u-boot-marvell/master

Thanks,
Stefan

> ---
> 
> Changes in v2:
> - Update i2c0 alias
> - Move i2c-gpio definition to root of device tree
> - Remove &i2c0 instead of just disabling it
> - Add r-by from Stefan
> 
>   arch/arm/dts/ac5-98dx35xx-atl-x240.dts | 30 ++++++++++++++++++++------
>   configs/x240_defconfig                 |  1 +
>   2 files changed, 24 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts
> index 820ec18b4355..c19b25925ba2 100644
> --- a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts
> +++ b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts
> @@ -16,7 +16,7 @@
>   		gpio0 = &gpio0;
>   		gpio1 = &gpio1;
>   		spi0 = &spi0;
> -		i2c0 = &i2c0;
> +		i2c0 = &i2cgpio;
>   		usb0 = &usb0;
>   		pinctrl0 = &pinctrl0;
>   	};
> @@ -40,6 +40,19 @@
>   			default-state = "on";
>   		};
>   	};
> +
> +	i2cgpio: i2c-gpio-0 {
> +			compatible = "i2c-gpio";
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +
> +			pinctrl-names = "default";
> +			pinctrl-0 =  <&i2c0_gpio>;
> +			scl-gpios = <&gpio0 26 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
> +			sda-gpios = <&gpio0 27 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
> +			i2c-gpio,delay-us = <2>;
> +			status = "okay";
> +		 };
>   };
>   
>   &nand {
> @@ -70,9 +83,7 @@
>   	status = "okay";
>   };
>   
> -&i2c0 {
> -	status = "okay";
> -
> +&i2cgpio {
>   	mux at 71 {
>   		#address-cells = <1>;
>   		#size-cells = <0>;
> @@ -177,8 +188,8 @@
>   	 * LED_OE_N              [23]
>   	 * USB_PWR_FLT_N         [24]
>   	 * SFP_INT_N             [25]
> -	 * I2C0_SCL              [26]
> -	 * I2C0_SDA              [27]
> +	 * I2C0_SCL              [26] (GPIO)
> +	 * I2C0_SDA              [27] (GPIO)
>   	 * USB_EN                [28]
>   	 * MONITOR_INT_N         [29]
>   	 * XM1_MDC               [30]
> @@ -201,7 +212,7 @@
>   	/*	     0    1    2    3    4    5    6    7    8    9 */
>   	pin-func = < 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff
>   		     0xff 0xff 1    1    1    1    0xff 0xff 0    0
> -		     0    0    0    0    0    0    1    1    0    0
> +		     0    0    0    0    0    0    0xff 0xff 0    0
>   		     1    1    1    1    0    0    0    0    0    0
>   		     0    0    0    1    1    1    >;
>   
> @@ -209,4 +220,9 @@
>   		marvell,pins = <0 1 2 3 4 5 6 7 8 9 10 11 16 17>;
>   		marvell,function = <2>;
>   	};
> +
> +	i2c0_gpio: i2c0-gpio-pins {
> +		marvell,pins = <26 27>;
> +		marvell,function = <0>;
> +	};
>   };
> diff --git a/configs/x240_defconfig b/configs/x240_defconfig
> index a78cb3ce6cbf..7d2b8603e6f4 100644
> --- a/configs/x240_defconfig
> +++ b/configs/x240_defconfig
> @@ -42,6 +42,7 @@ CONFIG_CLK_MVEBU=y
>   CONFIG_GPIO_HOG=y
>   CONFIG_DM_PCA953X=y
>   CONFIG_DM_I2C=y
> +CONFIG_DM_I2C_GPIO=y
>   CONFIG_SYS_I2C_MVTWSI=y
>   CONFIG_I2C_MUX=y
>   CONFIG_I2C_MUX_PCA954x=y

Viele Grüße,
Stefan Roese

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