Re: [PATCH v17 2/3] usb: USB Type-C connector class

[Mats Karrman]

On 2017-03-03 13:59, Heikki Krogerus wrote:

> On Fri, Mar 03, 2017 at 08:29:18AM +0100, Mats Karrman wrote:
> ....

> How would something like that sound to you guys?

Complicated... Need to marinate on that for a while ;)

> > My system is a bit different. It's an i.MX6 SoC with the typec phy and DP controller connected
> > directly to the SoC and it's using DTB/OF.
> Is this "DP controller" a controller that is capable of taking care of
> the USB Power Delivery communication with the partner regarding
> DisplayPort alternate mode?

No, the "DP controller" just talks DP and knows nothing about Type-C or USB PD.
It takes a video stream from the SoC and turns it into a DP link, set up and orchestrated
by the corresponding driver. And all the driver needs from Type-C is the plugged in / interrupt /
plugged out events.

The analog switching between USB / safe / DP signal levels in the Type-C connector is, I think,
best handled by the software doing the USB PD negotiation / Altmode handling (using some GPIOs).

> > Do we need to further standardize attributes under (each) specific alternate mode to
> > include things such as HPD for the DP mode?
> I'm not completely sure what kind of system you have, but I would
> imagine that if we had the bus, your DP controller driver would be the
> port (and partner) alternate mode driver. The bus would bind you to
> the typec phy.

So, both the DP controller and the USB PD phy are I2C devices, and now I have to make them both
attach to the AM bus as well?

BR,
Mats