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Message-ID: <ff147ac913c8aa32a64aeeb2244c11fd04955c3c.camel@mediatek.com>
Date: Fri, 10 Feb 2023 05:45:35 +0000
From: Jian Yang (杨戬) <Jian.Yang@...iatek.com>
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Subject: Re: [PATCH 2/2] dt-bindings: PCI: mediatek-gen3: Add support for
controlling power and reset
Dear Krzysztof,
On Fri, 2023-02-03 at 13:32 +0100, Krzysztof Kozlowski wrote:
> On 03/02/2023 10:38, Jian Yang (杨戬) wrote:
> > > > + 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.
>
> OK
>
> > >
> > > > + 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.
>
> No, I don't think we want individual properties like that. There is
> ongoing discussion about this:
>
https://lore.kernel.org/all/20221214095342.937303-1-alexander.stein@ew.tq-group.com/
>
> Feedback is welcomed - there. Don't create your own half-baked delays
> for different hardware designs.
Thanks for your helpful suggestion. I will remove that property of
delay-time in V2 patch and let the work-in-progress "GPIO delay" driver
to handle this requirement.
Best regards,
Jian Yang
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