HI Rob,

On Mon, Jul 20, 2020 at 7:26 PM Rob Herring [off-list ref] wrote:

On Tue, Jul 14, 2020 at 01:36:14PM +0200, Hans de Goede wrote:

quoted

This commit adds the minimum bindings required to allow describing which
altmodes a port supports. Currently this is limited to just specifying:

1. The svid, which is the id of the altmode, e.g. displayport altmode has
a svid of 0xff01.

2. The vdo, a 32 bit integer, typically used as a bitmask describing the
capabilities of the altmode, the bits in the vdo are specified in the
specification of the altmode, the dt-binding simply refers to the
specification as that is the canonical source of the meaning of the bits.

What if this information should be derived from information already in
DT (or would be there if alt mode connections are described)?

quoted

Later on we may want to extend the binding with extra properties specific
to some altmode, but for now this is sufficient to e.g. hook up
displayport alternate-mode.

I don't think this is sufficient as it doesn't describe how alternate
modes are connected to various components. This has been discussed some
here[1] with the CrOS folks. Maybe this is orthogonal, IDK, but I really
need something that is somewhat complete and not sprinkle a few new
properties at a time.

Just thought I'd add a link[2] to some amendments which were made to
the "switch"
proposal in the thread you added a link to (it has many responses, so
not sure if my
responses got lost in the thread). I also wrote a short summary[3].

Please ignore these if you've already taken a look at them :)

Best regards,

-Prashant

[2] https://lkml.org/lkml/2020/6/12/602
[3] https://lkml.org/lkml/2020/7/10/234

quoted

Signed-off-by: Hans de Goede <redacted>
---
Note I hope I got the yaml correct, this is my first time writing a
dt-binding in the new yaml style. I did run:
make dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/connector/usb-connector.yaml
and that was happy.

That aspect of it looks fine.

Rob

[1] https://lkml.org/lkml/2020/4/22/1819