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

[Stefan Roese]

On 10/5/23 09:54, Stefan Roese wrote:
> On 10/3/23 05:57, Chris Packham wrote:
>> This reverts commit 5c1c6b7306f2b4c0fd50c7cb5d757e245b93606e. The reason
>> for switching to i2c-gpio was due to an issue we were seeing in the
>> Linux kernel where the CPU would lock up on certain adverse I2C bus
>> conditions. We were never able to reproduce the lockup in U-Boot but
>> assumed that was probably just luck.
>>
>> Since then we have discovered that the lock up was due to the I2C
>> transaction offload engine in the I2C controller not coping with the
>> adverse bus conditions (basically it thinks there's another master and
>> waits for a STOP condition that never comes). U-Boot doesn't use the I2C
>> offload feature so is not susceptible to the lockup.
>>
>> We can therefore safely return to using the built-in I2C controller.
>>
>> 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


> Thanks,
> Stefan
> 
>> ---
>>
>>   arch/arm/dts/ac5-98dx35xx-atl-x240.dts | 30 ++++++--------------------
>>   configs/x240_defconfig                 |  1 -
>>   2 files changed, 7 insertions(+), 24 deletions(-)
>>
>> diff --git a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts 
>> b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts
>> index c19b25925ba2..820ec18b4355 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 = &i2cgpio;
>> +        i2c0 = &i2c0;
>>           usb0 = &usb0;
>>           pinctrl0 = &pinctrl0;
>>       };
>> @@ -40,19 +40,6 @@
>>               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 {
>> @@ -83,7 +70,9 @@
>>       status = "okay";
>>   };
>> -&i2cgpio {
>> +&i2c0 {
>> +    status = "okay";
>> +
>>       mux at 71 {
>>           #address-cells = <1>;
>>           #size-cells = <0>;
>> @@ -188,8 +177,8 @@
>>        * LED_OE_N              [23]
>>        * USB_PWR_FLT_N         [24]
>>        * SFP_INT_N             [25]
>> -     * I2C0_SCL              [26] (GPIO)
>> -     * I2C0_SDA              [27] (GPIO)
>> +     * I2C0_SCL              [26]
>> +     * I2C0_SDA              [27]
>>        * USB_EN                [28]
>>        * MONITOR_INT_N         [29]
>>        * XM1_MDC               [30]
>> @@ -212,7 +201,7 @@
>>       /*         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    0xff 0xff 0    0
>> +             0    0    0    0    0    0    1    1    0    0
>>                1    1    1    1    0    0    0    0    0    0
>>                0    0    0    1    1    1    >;
>> @@ -220,9 +209,4 @@
>>           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 0d5a19df25aa..4b1a761a9086 100644
>> --- a/configs/x240_defconfig
>> +++ b/configs/x240_defconfig
>> @@ -42,7 +42,6 @@ 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
> 

Viele Grüße,
Stefan Roese

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