Re: [PATCH 1/2] dt-bindings: usb: generic-ehci: document ignore-oc flag

From: Alan Stern
Date: Tue Feb 23 2021 - 11:10:27 EST


On Tue, Feb 23, 2021 at 05:04:57PM +0100, Álvaro Fernández Rojas wrote:
> Hi Alan,
>
> > El 23 feb 2021, a las 16:54, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> escribió:
> >
> > On Tue, Feb 23, 2021 at 04:50:04PM +0100, Álvaro Fernández Rojas wrote:
> >> Over-current reporting isn't supported on some platforms such as bcm63xx.
> >> These devices will incorrectly report over-current if this flag isn't properly
> >> activated.
> >>
> >> Signed-off-by: Álvaro Fernández Rojas <noltari@xxxxxxxxx>
> >> ---
> >> Documentation/devicetree/bindings/usb/generic-ehci.yaml | 5 +++++
> >> 1 file changed, 5 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/usb/generic-ehci.yaml b/Documentation/devicetree/bindings/usb/generic-ehci.yaml
> >> index cf83f2d9afac..294bbf02399e 100644
> >> --- a/Documentation/devicetree/bindings/usb/generic-ehci.yaml
> >> +++ b/Documentation/devicetree/bindings/usb/generic-ehci.yaml
> >> @@ -117,6 +117,11 @@ properties:
> >> Set this flag if EHCI has a Transaction Translator built into
> >> the root hub.
> >>
> >> + ignore-oc:
> >> + $ref: /schemas/types.yaml#/definitions/flag
> >> + description:
> >> + Set this flag for HCDs without over-current reporting support.
> >
> > This is not a good description of a device property. DT entries are
> > supposed to described the hardware, not talk about how to use it.
>
> Any suggestions on a proper description?
>
> >
> > When you say that the bcm63xx doesn't support over-current reporting,
> > what exactly do you mean? Do you mean that sometimes the hardware turns
> > on the over-current bit when an over-current isn't actually present? Or
> > do you mean something else?
>
> Yes, the hardware turns on the over-current bit with no over-current present.

Okay, in that case the property should be named something like
"spurious_oc", and the description should say something like:

Set this flag to indicate that the hardware sometimes turns on
the OC bit when an over-current isn't actually present.

Alan Stern