[v2,2/2] ARM: dts: am335x-bone-common: Add GPIO PHY reset on revision C3 board

Commit Message

Shengyu Qu Aug. 6, 2023, 8:50 a.m. UTC

This patch adds ethernet PHY reset GPIO config for Beaglebone Black
series boards with revision C3. This fixes a random phy startup failure
bug discussed at [1]. The GPIO pin used for reset is not used on older
revisions, so it is ok to apply to all board revisions. The reset timing
was discussed and tested at [2].

[1] https://forum.digikey.com/t/ethernet-device-is-not-detecting-on-ubuntu-20-04-lts-on-bbg/19948
[2] https://forum.beagleboard.org/t/recognizing-a-beaglebone-black-rev-c3-board/31249/

Signed-off-by: Robert Nelson <[e-mail]>
Signed-off-by: Shengyu Qu <[e-mail]>
---
Changes since v1:
 - Using /**/ rather than // to comment
---
 arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Tony Lindgren Aug. 9, 2023, 7:28 a.m. UTC | #1

* Shengyu Qu <[e-mail]> [230806 11:51]:
> This patch adds ethernet PHY reset GPIO config for Beaglebone Black
> series boards with revision C3. This fixes a random phy startup failure
> bug discussed at [1]. The GPIO pin used for reset is not used on older
> revisions, so it is ok to apply to all board revisions. The reset timing
> was discussed and tested at [2].

Nice, should we add some Fixes tag for this so it gets applied to
the stable kernels automatically?

Regards,

Tony

Shengyu Qu Aug. 9, 2023, 11:33 a.m. UTC | #2

Hello Tony,

I think that's OK. What should I do?

Best regards,

Shengyu

> * Shengyu Qu <[e-mail]> [230806 11:51]:
>> This patch adds ethernet PHY reset GPIO config for Beaglebone Black
>> series boards with revision C3. This fixes a random phy startup failure
>> bug discussed at [1]. The GPIO pin used for reset is not used on older
>> revisions, so it is ok to apply to all board revisions. The reset timing
>> was discussed and tested at [2].
> Nice, should we add some Fixes tag for this so it gets applied to
> the stable kernels automatically?
>
> Regards,
>
> Tony

Tony Lindgren Aug. 10, 2023, 6:27 a.m. UTC | #3

* Shengyu Qu <[e-mail]> [230809 11:33]:
> I think that's OK. What should I do?

Can you check if there is maybe some earlier Linux kernel commit
that this fixes?

If so we can have a Fixes tag and it will be applied automatically
to the stable kernels.

If it's adding new feature and no Fixes tag can be set, I can just
add Cc: stable for it.

Regards,

Tony

Shengyu Qu Aug. 10, 2023, 1:47 p.m. UTC | #4

Hi Tony,

No commit is fixed by this, since this is a hardware design problem on

older revision board.  :(

Best regards,

Shengyu

> * Shengyu Qu <[e-mail]> [230809 11:33]:
>> I think that's OK. What should I do?
> Can you check if there is maybe some earlier Linux kernel commit
> that this fixes?
>
> If so we can have a Fixes tag and it will be applied automatically
> to the stable kernels.
>
> If it's adding new feature and no Fixes tag can be set, I can just
> add Cc: stable for it.
>
> Regards,
>
> Tony

Tony Lindgren Aug. 14, 2023, 10:50 a.m. UTC | #5

* Shengyu Qu <[e-mail]> [230810 13:48]:
> Hi Tony,
> 
> No commit is fixed by this, since this is a hardware design problem on
> 
> older revision board.  :(

OK no worries, I'll add both to omap-for-v6.5/fixes. Depending how the
current -rc cycle goes, it may not get merged until for v6.6-rc1 FYI.

Thanks,

Tony

Patch

diff --git a/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi b/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
index 7b784a87efc6..96451c8a815c 100644
--- a/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
+++ b/arch/arm/boot/dts/ti/omap/am335x-bone-common.dtsi
@@ -145,6 +145,8 @@  davinci_mdio_default: davinci-mdio-default-pins {
 			/* MDIO */
 			AM33XX_PADCONF(AM335X_PIN_MDIO, PIN_INPUT_PULLUP | SLEWCTRL_FAST, MUX_MODE0)
 			AM33XX_PADCONF(AM335X_PIN_MDC, PIN_OUTPUT_PULLUP, MUX_MODE0)
+			/* Added to support GPIO controlled PHY reset */
+			AM33XX_PADCONF(AM335X_PIN_UART0_CTSN, PIN_OUTPUT_PULLUP, MUX_MODE7)
 		>;
 	};
 
@@ -153,6 +155,8 @@  davinci_mdio_sleep: davinci-mdio-sleep-pins {
 			/* MDIO reset value */
 			AM33XX_PADCONF(AM335X_PIN_MDIO, PIN_INPUT_PULLDOWN, MUX_MODE7)
 			AM33XX_PADCONF(AM335X_PIN_MDC, PIN_INPUT_PULLDOWN, MUX_MODE7)
+			/* Added to support GPIO controlled PHY reset */
+			AM33XX_PADCONF(AM335X_PIN_UART0_CTSN, PIN_INPUT_PULLDOWN, MUX_MODE7)
 		>;
 	};
 
@@ -378,6 +382,10 @@  &davinci_mdio_sw {
 
 	ethphy0: ethernet-phy@0 {
 		reg = <0>;
+		/* Support GPIO reset on revision C3 boards */
+		reset-gpios = <&gpio1 8 GPIO_ACTIVE_LOW>;
+		reset-assert-us = <300>;
+		reset-deassert-us = <6500>;
 	};
 };