[PATCH] arm: mvebu: x240: Use i2c-gpio instead of built in controller
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@gmail.com --- This is dependent on a bug-fix for the i2c-gpio driver I just sent out[1] (sorry I should have sent them as a series but I thought this would take me longer to test than it did).
[1] - https://lore.kernel.org/u-boot/20230720023107.1184147-1-judge.packham@gmail....
arch/arm/dts/ac5-98dx35xx-atl-x240.dts | 30 ++++++++++++++++++++++---- configs/x240_defconfig | 1 + 2 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts index 820ec18b4355..d47220520b9e 100644 --- a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts +++ b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts @@ -71,8 +71,25 @@ };
&i2c0 { - status = "okay"; + status = "disabled"; +};
+&{/} { + 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"; + }; +}; + +&i2cgpio { mux@71 { #address-cells = <1>; #size-cells = <0>; @@ -177,8 +194,8 @@ * 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 +218,7 @@ /* 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 +226,9 @@ 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 6d25c5ae3fcf..e8589d636081 100644 --- a/configs/x240_defconfig +++ b/configs/x240_defconfig @@ -43,6 +43,7 @@ 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
Hi Me,
On Thu, Jul 20, 2023 at 3:03 PM Chris Packham judge.packham@gmail.com 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@gmail.com
This is dependent on a bug-fix for the i2c-gpio driver I just sent out[1] (sorry I should have sent them as a series but I thought this would take me longer to test than it did).
[1] - https://lore.kernel.org/u-boot/20230720023107.1184147-1-judge.packham@gmail....
arch/arm/dts/ac5-98dx35xx-atl-x240.dts | 30 ++++++++++++++++++++++---- configs/x240_defconfig | 1 + 2 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts index 820ec18b4355..d47220520b9e 100644 --- a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts +++ b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts @@ -71,8 +71,25 @@ };
&i2c0 {
status = "okay";
status = "disabled";+};
I'll remove this section completely. I did want to make it clear that we're using the same pins just as GPIOs instead of the dedicated I2C mode which has issues but that can be explained better in the commit message.
+&{/} {
I should probably move this part up to the root node rather than addressing it here.
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";};+};
+&i2cgpio { mux@71 { #address-cells = <1>; #size-cells = <0>; @@ -177,8 +194,8 @@ * 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 +218,7 @@ /* 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 +226,9 @@ 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 6d25c5ae3fcf..e8589d636081 100644 --- a/configs/x240_defconfig +++ b/configs/x240_defconfig @@ -43,6 +43,7 @@ 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 -- 2.41.0
Hi Chris,
On 7/20/23 23:01, Chris Packham wrote:
Hi Me,
On Thu, Jul 20, 2023 at 3:03 PM Chris Packham judge.packham@gmail.com 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@gmail.com
This is dependent on a bug-fix for the i2c-gpio driver I just sent out[1] (sorry I should have sent them as a series but I thought this would take me longer to test than it did).
[1] - https://lore.kernel.org/u-boot/20230720023107.1184147-1-judge.packham@gmail....
arch/arm/dts/ac5-98dx35xx-atl-x240.dts | 30 ++++++++++++++++++++++---- configs/x240_defconfig | 1 + 2 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts index 820ec18b4355..d47220520b9e 100644 --- a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts +++ b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts @@ -71,8 +71,25 @@ };
&i2c0 {
status = "okay";
status = "disabled";+};
I'll remove this section completely. I did want to make it clear that we're using the same pins just as GPIOs instead of the dedicated I2C mode which has issues but that can be explained better in the commit message.
+&{/} {
I should probably move this part up to the root node rather than addressing it here.
All these comments sound like a "good think" to do.
Feel free to add my:
Reviewed-by: Stefan Roese sr@denx.de
in the next version.
Thanks, Stefan
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";};+};
+&i2cgpio { mux@71 { #address-cells = <1>; #size-cells = <0>; @@ -177,8 +194,8 @@ * 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 +218,7 @@ /* 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 +226,9 @@ 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 6d25c5ae3fcf..e8589d636081 100644 --- a/configs/x240_defconfig +++ b/configs/x240_defconfig @@ -43,6 +43,7 @@ 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 -- 2.41.0
Viele Grüße, Stefan Roese
participants (2)
-
Chris Packham -
Stefan Roese