On 27/11/2023 08:09, Macpaul Lin wrote:
> On 11/25/23 18:37, Krzysztof Kozlowski and Chunfeng Yun wrote:
>>
>>
>> External email : Please do not click links or open attachments until you
>> have verified the sender or the content.
>>
>> On 25/11/2023 02:23, Chunfeng Yun wrote:
>>> Due to some old SoCs with shared t-phy only support force-mode switch, and
>>> can't use compatible to distinguish between shared and non-shared t-phy,
>>> add a property to supported it.
>>> But now prefer to use "mediatek,syscon-type" on new SoC as far as possible.
>>>
>>> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
>>> ---
>>> Documentation/devicetree/bindings/phy/mediatek,tphy.yaml | 6 ++++++
>>> 1 file changed, 6 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml b/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
>>> index 2bb91542e984..eedba5b7025e 100644
>>> --- a/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
>>> +++ b/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
>>> @@ -235,6 +235,12 @@ patternProperties:
>>> Specify the flag to enable BC1.2 if support it
>>> type: boolean
>>>
>>> + mediatek,force-mode:
>>> + description:
>>> + Use force mode to switch shared phy mode, perfer to use the bellow
>>
>> I still do not understand what is the "force mode" you want to use. What
>> modes do you have? What are the characteristics of force mode?
>>
>> Also, please run spellcheck.
>>
>> Best regards,
>> Krzysztof
>>
>
> Thanks!
>
> 1. I've tested this patch and it could solve the clock unstable for
> XHCI1 on mt8195 or mt8395 during system boot up or during
> unload/reload the phy driver.
>
> The error message has been listed as follows.
>
> [ 13.849936][ T72] xhci-mtk 11290000.usb: supply vbus not found,
> using dummy regulator
> [ 13.851300][ T72] xhci-mtk 11290000.usb: uwk - reg:0x400, version:104
> [ 13.852624][ T72] xhci-mtk 11290000.usb: xHCI Host Controller
> [ 13.853393][ T72] xhci-mtk 11290000.usb: new USB bus registered,
> assigned bus number 3
> [ 13.874490][ T72] xhci-mtk 11290000.usb: clocks are not stable (0x3d0f)
> [ 13.875369][ T72] xhci-mtk 11290000.usb: can't setup: -110
> [ 13.876091][ T72] xhci-mtk 11290000.usb: USB bus 3 deregistered
> [ 13.877081][ T72] xhci-mtk: probe of 11290000.usb failed with error
> -110
>
> 2. This is a fix patch to XHCI1 since MT8195 has been upstream.
> Please add "Fixes:" tags and "Cc: stable@xxxxxxxxxx" to back ward
> porting to previous stable trees.
>
> For example, add
> Fixes: 6b5ef194611e5 ("phy: mediatek: tphy: remove macros to prepare
> bitfield")
> is suggested since the force-mode was missing in the previous
> implementation which causes hardware function was abnormal.
> However, add
> Fixes: 33d18746fa514 ("phy: phy-mtk-tphy: use new io helpers to access
> register")
> will be better since the USB support for mt8195 is already enabled in
> late 2021.
>
> 3. How about we revise the description as follows for more precisely?
>
> mediatek,force-mode:
> description:
> The force mode is used to manually switch the shared PHY mode
> between USB and PCIe. When force-mode is set, the USB 3.0 mode
> will be selected. This is typically required for older SoCs
> that do not automatically manage PHY mode switching.
> For newer SoCs that support it, it is preferable to use the
> "mediatek,syscon-type" property instead.
> type: boolean
Again, what is force-mode? It looks like you wrote bindings for the
driver behavior. Bindings describe hardware, not how the driver should
behave. The property might be reasonable, but you must describe here
hardware characteristics/issue/etc.
Also, your driver change suggests this is compatible specific, so why it
cannot be deduced from compatible?
Best regards,
Krzysztof
