On Thu, Sep 21, 2017 at 4:25 AM, Sakari Ailus <sakari.ai...@linux.intel.com> wrote: > Hi Rob, > > Thanks for the reply. > > On Wed, Sep 20, 2017 at 03:53:13PM -0500, Rob Herring wrote: >> On Mon, Sep 18, 2017 at 11:25:04AM +0300, Sakari Ailus wrote: >> > A lot of devices do not need and do not document port or endpoint >> > numbering at all, e.g. in case where there's just a single port and a >> > single endpoint. Whereas this is just common sense, document it to make it >> > explicit. >> > >> > Signed-off-by: Sakari Ailus <sakari.ai...@linux.intel.com> >> > --- >> > Documentation/devicetree/bindings/media/video-interfaces.txt | 12 >> > ++++++++++++ >> > 1 file changed, 12 insertions(+) >> >> This is fine, but bindings should still be explicit. Otherwise, I'm >> wondering if it's a single port/endpoint or they just forgot to document >> it. And I shouldn't have to look at the example to infer that. >> >> Acked-by: Rob Herring <r...@kernel.org> > > The purpose of the patch was to actually document port and endpoint > numbering for devices for which it is not documented, not to suggest that > this would be omitted in in binding documentation. The fact is that I > couldn't find documentation for endpoint numbering for a single device > under Documentation/devicetree/bindings/media/ . Yet I haven't come across > DT source where other than zero would have been used. And the drivers > (mostly?) have ignored endpoint numbers so far.
That's surprising. I know there are some for display controllers and it's a common review comment I give. > > Some bindings have been omitted on the grounds that they're documented in > video-interfaces.txt. > > What would you think of the following? I'm not sure it'd really belong > there, but it'd be a small piece of documentation one can easily refer to. Looks good. > > > From e735979005244eb10597fe5333130b93e41d5a38 Mon Sep 17 00:00:00 2001 > From: Sakari Ailus <sakari.ai...@linux.intel.com> > Date: Mon, 18 Sep 2017 11:15:53 +0300 > Subject: [PATCH 1/1] dt: bindings: media: Document practices for DT bindings, > ports, endpoints > > Port and endpoint numbering has been omitted in DT binding documentation > for a large number of devices. Also common properties the device uses have > been missed in binding documentation. Make it explicit that these things > need to be documented. > > Signed-off-by: Sakari Ailus <sakari.ai...@linux.intel.com> > --- > .../devicetree/bindings/media/video-interfaces.txt | 15 > +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt > b/Documentation/devicetree/bindings/media/video-interfaces.txt > index 852041a..3c5382f 100644 > --- a/Documentation/devicetree/bindings/media/video-interfaces.txt > +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt > @@ -55,6 +55,21 @@ divided into two separate ITU-R BT.656 8-bit busses. In > such case bus-width > and data-shift properties can be used to assign physical data lines to each > endpoint node (logical bus). > > +Documenting bindings for devices > +-------------------------------- > + > +All required and optional bindings the device supports shall be explicitly > +documented in device DT binding documentation. This also includes port and > +endpoint numbering for the device. > + > +Port and endpoint numbering > +--------------------------- > + > +Old binding documentation may have omitted explicitly specifying port and > +endpoint numbers. This often applies to devices that have a single port and a > +single endpoint in that port. In this case, the only valid port number for > such > +a device is zero. The same applies for devices for which bindings do not > +document endpoint numbering: only zero is a valid endpoint. > > Required properties > ------------------- > -- > 2.7.4 > > -- > Sakari Ailus > sakari.ai...@linux.intel.com
