Re: usb typec not doing handling in-kernel

[Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>]

Hi Guenter,

Am Montag, 13. August 2018, 14:29:15 CEST schrieb Guenter Roeck:
> On 08/13/2018 03:36 AM, Heiko Stuebner wrote:
> > Hi,
> > 
> > I'm currently trying to wrap my head around the new typec subsystem and
> > also how to do it correctly on Rockchip rk3399 devices.
> > 
> > The issue (and Guenter might know quite a bit about that) is that on
> > ChromeOS devices the embedded controller hides the whole tcpm/vdm
> > logic from the operating system and just provides a custom interface to
> > query things like cable state, display-port hotplug status and so on.
> > 
> > So right now the rk3399-typec-phy uses that extcon-based interface to
> > get all status changes but that of course leaves out all systems directly
> > talking to a fusb302. I did a small drawing to showcase that:
> > 
> > -------------    ------------------
> > | typec-phy |----| extcon-cros-ec |\
> > -------------    ------------------ \
> >       |        \                      \
> > -------------  \ ------------------   \ -----------
> > |  cdn-dp   |   \|     ?????      |-----| fusb302 |
> > -------------    ------------------     -----------
> > 
> > So to bring everything on the same page, I guess the cros-ec extcon
> > (drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec
> > functions instead of implementing an extcon? But from reading into the
> > typec code, it somehow looks like the typec framework expects to be in
> > control of things like altmode negotiations, or am I misreading something?
> > 
> I used to have a patch for the cros-ec extcon driver which ties it into the
> typec subsystem. Let me see if I can dig it up.

were your archeological skills working in finding said old patch?

Thanks
Heiko