(CC+ Bjorn) On Wed, Jun 29, 2022 at 4:55 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote: > > Quoting Prashant Malani (2022-06-29 15:55:10) > > On Wed, Jun 29, 2022 at 2:58 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote: > > > > > > My understanding is there are 4 DP lanes on it6505 and two lanes are > > > connected to one usb-c-connector and the other two lanes are connected > > > to a different usb-c-connector. The IT6505 driver will send DP out on > > > the associated two DP lanes depending on which usb-c-connector has DP > > > pins assigned by the typec manager. > [...] > > > > We can adopt this binding, but from what I gathered in this thread, that > > shouldn't be done, because IT6505 isn't meant to be aware of Type-C > > connections at all. > > How will the driver know which usb-c-connector to route DP to without > making the binding aware of typec connections? I agree with you; I'm saying my interpretation of the comments of this thread are that it's not the intended usage of the it6505 part, so the driver shouldn't be updated to support that. > > HPD can be signalled out of band, or not at all (no-hpd). I suspect it's > valid to ignore/disconnect the HPD pin here and start/stop DP when, for > example, the HPD pin toggles within a dp-connector. HPD could be > signaled directly to the kernel via an out of band gpio going from the > dp-connector to the SoC. In this case HPD for each dp-connector could be > a different gpio and the driver may be required to arbitrate between the > two dp-connectors with some 'first to signal wins' logic or something. Sure, it's possible. I just didn't see anything in the anx7625 datasheet to suggest it supported 2x1-lane DP outputs. For that matter I don't think even it6505 supports > 1 DP sink (based on my reading of the datasheet), but I don't have too much experience with these parts. > > My interpretation of the current mode-switch search code [1] is that > > a top level property of "mode-switch" is required. > > Yeah that's how it is right now, but does it have to stay that way? > Could the code search the graph and look for a matching node that's > registered with the typec framework? I'll have to get back to you on that after reading the code a bit more. Maybe Heikki or Bjorn have some comments about it. The ACPI Type-C ports do require a device handle labelled "mode-switch" which points to the switch device.
