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    SubjectRe: [PATCH v17 2/3] usb: USB Type-C connector class
    Hi Mats,

    On Fri, Mar 03, 2017 at 08:27:08PM +0100, Mats Karrman wrote:
    > 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 ;)

    Sorry about the bad explanation :-). Let me try again.. I'm simply
    looking for a method that is as scalable as possible to handle the
    alternate modes, basically how to couple the different components
    involved. Bus would feel like the best approach at the moment.

    > > > 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.

    Got it.

    > 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?

    The DP controller would provide the driver and the USB PD phy
    (actually, the typec class) the device.

    Would it be a problem to register these I2C devices with some other
    subsystem, was it extcon or something like AM bus? It really would not
    be that uncommon. Or have I misunderstood your question?


    Thanks,

    --
    heikki

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