[PATCH] arm64: dts: meson: fix PHY deassert timing requirements

[Neil Armstrong]

On 07/04/2021 16:21, Stefan Agner wrote:
> On 2021-04-07 15:31, Neil Armstrong wrote:
>> Hi,
>>
>> On 06/04/2021 19:47, Stefan Agner wrote:
>>> The sync of the device tree and dt-bindings from Linux v5.6-rc2
>>> 11a48a5a18c6 ("Linux 5.6-rc2") causes Ethernet to break on some
>>> ODROID-C2.
>>>
>>> Meanwhile a fix to increase the reset timing has been added to Linux.
>>> Instead of reverting the offending commit, use the new reset timing
>>> from upstream Linux commit c183c406c432 ("arm64: dts: meson: fix PHY
>>> deassert timing requirements").
>>>
>>> Fixes: dd5f2351e99a ("arm64: dts: meson: sync dt and bindings from v5.6-rc2")
>>> Signed-off-by: Stefan Agner <stefan at agner.ch>
>>> ---
>>>  arch/arm/dts/meson-g12b-odroid-n2.dtsi | 2 +-
>>>  arch/arm/dts/meson-gxbb-nanopi-k2.dts  | 2 +-
>>>  arch/arm/dts/meson-gxbb-odroidc2.dts   | 2 +-
>>>  arch/arm/dts/meson-gxm-khadas-vim2.dts | 2 +-
>>>  4 files changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/arm/dts/meson-g12b-odroid-n2.dtsi b/arch/arm/dts/meson-g12b-odroid-n2.dtsi
>>> index 6982632ae6..39a09661c5 100644
>>> --- a/arch/arm/dts/meson-g12b-odroid-n2.dtsi
>>> +++ b/arch/arm/dts/meson-g12b-odroid-n2.dtsi
>>> @@ -413,7 +413,7 @@
>>>  		max-speed = <1000>;
>>>
>>>  		reset-assert-us = <10000>;
>>> -		reset-deassert-us = <30000>;
>>> +		reset-deassert-us = <80000>;
>>
>> In fact, these are not used by current U-boot, support for
>> reset/deassert in PHY node
>> is not yet supported in U-Boot. This first step was to switch to
>> DM_MDIO and use the
>> proper Designware glue, the second step is to find how to make use of
>> these properties.
> 
> Hm, that is strange, I have users reporting that this patch fixes the
> issue on their devices. I guess it might be that the problem does not
> always appear and it was just (bad) luck.
> 
>>
>> Concerning the patch, I'll prefer you sync the DT with v5.11 instead.
> 
> We have multiple reports of non-working ODROID-C2 which worked in
> previous U-Boot releases:
> https://github.com/home-assistant/operating-system/issues/1202
> 
> Similar reports exist in Armbian Forums as well.
> 
> Until we have proper PHY reset/deassert support, I'd suggest to revert
> dd5f2351e99a ("arm64: dts: meson: sync dt and bindings from v5.6-rc2")
> partially then...

Reverting this is clearly not a solution, the intermediate solution is to
put back the previous reset properties like it was done for multiple boards
like in arch/arm/dts/meson-sm1-odroid-c4-u-boot.dtsi :

==========================================================================
diff --git a/arch/arm/dts/meson-gxbb-odroidc2-u-boot.dtsi b/arch/arm/dts/meson-gxbb-odroidc2-u-boot.dtsi
index 90087b00db..f1e6914351 100644
--- a/arch/arm/dts/meson-gxbb-odroidc2-u-boot.dtsi
+++ b/arch/arm/dts/meson-gxbb-odroidc2-u-boot.dtsi
@@ -29,6 +29,12 @@
        };
 };

+&ethmac {
+        snps,reset-gpio = <&gpio GPIOZ_14 0>;
+        snps,reset-delays-us = <0 10000 1000000>;
+        snps,reset-active-low;
+};
+
 &usb0 {
        status = "disabled";
 };
==========================================================================

Neil
> 
> --
> Stefan
> 
> 
>>
>> Neil
>>
>>>  		reset-gpios = <&gpio GPIOZ_15 (GPIO_ACTIVE_LOW | GPIO_OPEN_DRAIN)>;
>>>
>>>  		interrupt-parent = <&gpio_intc>;
>>> diff --git a/arch/arm/dts/meson-gxbb-nanopi-k2.dts b/arch/arm/dts/meson-gxbb-nanopi-k2.dts
>>> index 7be3e35409..de27beafe9 100644
>>> --- a/arch/arm/dts/meson-gxbb-nanopi-k2.dts
>>> +++ b/arch/arm/dts/meson-gxbb-nanopi-k2.dts
>>> @@ -165,7 +165,7 @@
>>>  			reg = <0>;
>>>
>>>  			reset-assert-us = <10000>;
>>> -			reset-deassert-us = <30000>;
>>> +			reset-deassert-us = <80000>;
>>>  			reset-gpios = <&gpio GPIOZ_14 GPIO_ACTIVE_LOW>;
>>>
>>>  			interrupt-parent = <&gpio_intc>;
>>> diff --git a/arch/arm/dts/meson-gxbb-odroidc2.dts b/arch/arm/dts/meson-gxbb-odroidc2.dts
>>> index 70fcfb7b06..50de1d01e5 100644
>>> --- a/arch/arm/dts/meson-gxbb-odroidc2.dts
>>> +++ b/arch/arm/dts/meson-gxbb-odroidc2.dts
>>> @@ -200,7 +200,7 @@
>>>  			reg = <0>;
>>>
>>>  			reset-assert-us = <10000>;
>>> -			reset-deassert-us = <30000>;
>>> +			reset-deassert-us = <80000>;
>>>  			reset-gpios = <&gpio GPIOZ_14 GPIO_ACTIVE_LOW>;
>>>
>>>  			interrupt-parent = <&gpio_intc>;
>>> diff --git a/arch/arm/dts/meson-gxm-khadas-vim2.dts b/arch/arm/dts/meson-gxm-khadas-vim2.dts
>>> index bff8ec2c1c..e38d9e50ca 100644
>>> --- a/arch/arm/dts/meson-gxm-khadas-vim2.dts
>>> +++ b/arch/arm/dts/meson-gxm-khadas-vim2.dts
>>> @@ -194,7 +194,7 @@
>>>  		reg = <0>;
>>>
>>>  		reset-assert-us = <10000>;
>>> -		reset-deassert-us = <30000>;
>>> +		reset-deassert-us = <80000>;
>>>  		reset-gpios = <&gpio GPIOZ_14 GPIO_ACTIVE_LOW>;
>>>
>>>  		interrupt-parent = <&gpio_intc>;
>>>