On Wed, Aug 25, 2021 at 10:01:05AM +0300, Heikki Krogerus wrote:

On Wed, Aug 25, 2021 at 08:55:41AM +0300, Felipe Balbi wrote:

quoted

Hi,

Nehal Bakulchandra Shah [off-list ref] writes:

quoted

For AMD platform there is a requirement to enable user space role
switch from host to device and device to host as customer platform is not
completely capable of OTG i.e. with type C controller it does not have PD
to support role switching. Hence, based ACPI/EC interrupt role switch is
triggered by the usemode script running in background.

                   usermode ?

Couldn't you capture that ACPI/EC interrupt in kernel?

quoted

quoted

Signed-off-by: Nehal Bakulchandra Shah <redacted>

I'm okay with this, just wondering if we need to Document the property
somewhere.

@Heikki, is there a place to document these private properties that's
not on DT binding document?

The build-in properties are not documented separately. I've always
tried to supply DT bindings for all new properties I've proposed.

In this case though, do we need the new property at all? Why not just
register a normal USB role switch on this platform? It can be either a
dummy role switch that only passes the user space input to dwc3, or,
perhaps ideally, it would also be a driver that captures that ACPI/EC
event/notification and then passes the information from it to dwc3.

Please ignore the above question. Sorry. Let me try again...

The question is: why not just capture that ACPI/EC "interrupt" in
kernel and then just use that information to set the dwc3 role switch?
No extra properties needed.


thanks,

-- 
heikki