Re: [PATCH 1/2] dt-bindings: phy: mediatek: tphy: add a property for force-mode switch

[Chunfeng Yun (云春峰)]

On Mon, 2023-11-27 at 14:37 +0100, AngeloGioacchino Del Regno wrote:
> Il 27/11/23 08:21, Krzysztof Kozlowski ha scritto:
> > 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.
> 
> Two questions:
> 1. Why is it *not* possible to use the compatible string to
> distinguish between
>     shared and non-shared T-PHYs?
There may be shared t-phy and non-shared t-phy at the same time on the
SoC.

> 2. If we really can't use compatibles, what's the reason why we can't
> use the
>     "mediatek,syscon-type" property?
It need hardware support it, it uses a top pericfg register to tell the
phy that the mode we want before power on the phy controller.


> 
> Regards,
> Angelo
> 
> > > > > 
> > > > > 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
> 
>