Re: [PATCH 1/2] scsi: ufs: drockchip,rk3576-ufshc: dt-bindings: Add new mphy reset item

[Krzysztof Kozlowski <krzk@kernel.org>]

On 11/03/2026 14:29, Shawn Lin wrote:
> Hi Krzysztof
> 
> 在 2026/03/11 星期三 21:10, Krzysztof Kozlowski 写道:
>> On Wed, Mar 11, 2026 at 09:40:17AM +0800, Shawn Lin wrote:
>>> Add the mphy reset property to the devicetree bindings for the Rockchip
>>> RK3576 UFS host controller. The mphy reset signal is used to reset the
>>> physical adapter. Resetting other components while leaving the mphy
>>> unreset may occasionally prevent the UFS controller from successfully
>>> linking up with the device.
>>>
>>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>>> ---
>>>
>>>   Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml | 7 ++++---
>>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml b/Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml
>>> index c7d17cf4..e738153 100644
>>> --- a/Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml
>>> +++ b/Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml
>>> @@ -41,7 +41,7 @@ properties:
>>>       maxItems: 1
>>>   
>>>     resets:
>>> -    maxItems: 4
>>> +    maxItems: 5
>>>   
>>>     reset-names:
>>>       items:
>>> @@ -49,6 +49,7 @@ properties:
>>>         - const: sys
>>>         - const: ufs
>>>         - const: grf
>>> +      - const: mphy
>>
>> ABI break here and in the driver. Considering this was merged year ago,
>> so for sure it was tested and was working. Otherwise commit msg would
>> explain the actual bug affecting users.
>>
> 
> Thanks for your review.
> 
> You are absolutely right that this change technically breaks the ABI in
> the device tree bindings by increasing maxItems and adding a new entry.
> Although the driver is using devm_reset_control_array_get_exclusive(),
> so the old DTB and new DTB should both work.

Ah, I missed that. Please mention it briefly in commit msg to indicate
that Linux is not affected.

> 
> The issue this series fixes (UFS link-up failure when mphy is not
> explicitly reset) is an intermittent hardware bug that is difficult to
> reproduce. It only occurs under specific timing conditions with certain
> chips. We recently encountered this issue consistently in our downstream
> testing and identified the root cause. We are syncing this critical fix
> to upstream immediately to prevent stability issues for users. I will
> update the commit message to explicitly describe this hard-to-reproduce
> bug and the specific failure mode, and probably add a fixes tag.
> 
> Does the above sound the right approach to you?

Yes, please include parts of above, that it is hard to reproduce but it
does happen, in the commit msg.


Best regards,
Krzysztof