Re: [RFC PATCH 2/3] dt-bindings: gpio: Add binding documentation for Etron EJ168/EJ188/EJ198

[Martin Blumenstingl]

Hi Linus,

On Wed, Oct 14, 2020 at 2:43 PM Rob Herring <robh+dt@xxxxxxxxxx> wrote:
>
> On Tue, Oct 13, 2020 at 8:27 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> >
> > On Wed, Oct 7, 2020 at 9:58 PM Martin Blumenstingl
> > <martin.blumenstingl@xxxxxxxxxxxxxx> wrote:
> > > On Wed, Oct 7, 2020 at 11:19 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> > > > On Sun, Oct 4, 2020 at 8:00 PM Martin Blumenstingl
> > > > <martin.blumenstingl@xxxxxxxxxxxxxx> wrote:
> > > >
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    enum:
> > > > > +      - pci1b6f,7023
> > > > > +      - pci1b6f,7052
> > > >
> > > > I think it is better to let the PCI driver for the whole hardware in
> > > > drivers/usb/host/xhci-pci.c probe from the PCI configuration space
> > > > numbers, and then add a gpio_chip to xhci-pci.c.
> > >
> > > to have everything consistent I will move the binding to
> > > Documentation/devicetree/bindings/usb
> >
> > I do not understand why a PCI device would need a DT binding
> > at all. They just probe from the magic number in the PCI
> > config space, they spawn struct pci_dev PCI devices, not the
> > type of platform devices coming out of the DT parser code.
> > No DT compatible needed.
>
> Same reason for all the discoverable buses need bindings. There can be
> parts that are not discoverable or connections with non-discoverable
> nodes. There's also cases where the discoverable device has to be
> powered, reset deasserted, clocks enabled, etc. first to be
> discovered.
>
> If the GPIOs here had connections elsewhere in the DT, then we have to
> describe the provider in DT.
this is exactly what I need it for: that platform has hand-written
.dts files and I need to wire up a GPIO LED


Best regards,
Martin