Re: [PATCH 2/2] dt-bindings: PCI: mediatek-gen3: Add support for controlling power and reset

[Jian Yang (杨戬)]

Dear Krzysztof,

Sorry for the late response and thanks for your comment.

On Wed, 2023-01-11 at 10:30 +0100, Krzysztof Kozlowski wrote:
> On 11/01/2023 04:28, Jian Yang wrote:
> > From: "jian.yang" <jian.yang@xxxxxxxxxxxx>
> > 
> > Add new properties to support control power supplies and reset pin
> > of
> > a downstream component.
> > 
> > Signed-off-by: jian.yang <jian.yang@xxxxxxxxxxxx>
> 
> Please use scripts/get_maintainers.pl to get a list of necessary
> people
> and lists to CC.  It might happen, that command when run on an older
> kernel, gives you outdated entries.  Therefore please be sure you
> base
> your patches on recent Linux kernel.
> 
> > ---
> >  .../bindings/pci/mediatek-pcie-gen3.yaml      | 23
> > +++++++++++++++++++
> >  1 file changed, 23 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/pci/mediatek-pcie-
> > gen3.yaml b/Documentation/devicetree/bindings/pci/mediatek-pcie-
> > gen3.yaml
> > index 7e8c7a2a5f9b..46149cc63989 100644
> > --- a/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
> > +++ b/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml
> > @@ -84,6 +84,29 @@ properties:
> >      items:
> >        enum: [ phy, mac ]
> >  
> > +  pcie1v8-supply:
> > +    description:
> > +      The regulator phandle that provides 1.8V power to downstream
> > component.
> > +
> > +  pcie3v3-supply:
> > +    description:
> > +      The regulator phandle that provides 3.3V power to downstream
> > component.
> > +
> > +  pcie12v-supply:
> > +    description:
> > +      The regulator phandle that provides 12V power to downstream
> > component.
> > +
> > +  dsc-reset-gpios:
> > +    description:
> > +      The reset GPIO of a downstream component.
> 
> Why you cannot use standard reset-gpios property?

The "dsc-reset-gpios" represents an extra reset pin other than PERST#
required by a PCIe downstream device. But the "reset-gpios", described
in "pci.txt", represents the PERST#. So I tend to add a new property to
meet this requirement.

> 
> > +    maxItems: 1
> > +
> > +  dsc-reset-msleep:
> 
> Wrong property unit/suffix.

Thanks for the correction. I will modify it in v2 patch.

> 
> > +    description:
> > +      The delay time between assertion and de-assertion of a
> > downstream
> > +      component's reset GPIO.
> 
> Why this should be a property of DT?

Same as the reason I described above. I suppose we need to add a
property to let user determine the delay time due to differences
in requirements between various devices.

> 
> > +    maxItems: 1
> 
> maxItems of what?

Seems unnecessary to add a "maxItems" here. Also I will remove it in v2
patch. Thanks a lot.

Best regards,
Jian Yang