On 06.07.2017 18:11, Thierry Reding wrote: > On Thu, Jul 06, 2017 at 01:04:40PM +0000, Marcel Ziswiler wrote: >> On Thu, 2017-07-06 at 14:03 +0200, Thierry Reding wrote: >>> On Thu, Jul 06, 2017 at 02:20:04AM +0300, Dmitry Osipenko wrote: >>>> On 06.07.2017 01:54, Stephen Warren wrote: >>>>> On 07/05/2017 04:13 PM, Dmitry Osipenko wrote: >>>>>> On 05.07.2017 23:31, Stephen Warren wrote: >>>>>>> On 07/05/2017 11:19 AM, Dmitry Osipenko wrote: >>>>>>>> Some time ago Thierry Reding sent out patches that enabled >>>>>>>> UDC on NVIDIA >>>>>>>> Tegra, unfortunately they haven't got enough traction to >>>>>>>> get into the >>>>>>>> kernel. I've rebased those patches and added a fix for the >>>>>>>> Ethernet USB >>>>>>>> Gadget on Tegra20, Marc Dietrich tested UDC driver on AC100 >>>>>>>> and Nicolas >>>>>>>> Chauvet on TK1. Like an original patchset, this series adds >>>>>>>> support for >>>>>>>> the peripheral mode only. >>>>>>> >>>>>>> Does this mean that the relevant ports no longer support host >>>>>>> mode? That's going >>>>>>> to be a user-visible regression, which doesn't sound like a >>>>>>> good idea. Isn't OTG >>>>>>> possible instead? >>>>>> >>>>>> We are going to switch only AC100 and TrimSlice to use the UDC >>>>>> driver. >>>>> >>>>> Really? I saw patches in the series for Beaver, Dalmore, and >>>>> Jetson TK1 too. >>>>> >>>> >>>> Yes, the "PHY" and "EHCI" nodes are disabled on those boards in DT. >>>> >>>>>> Do you >>>>>> know whether that port is working in a host mode with the >>>>>> tegra-ehci driver on >>>>>> these devices? >>>>> >>>>> If any USB port is enabled in the DT, it was certainly validated >>>>> at some point. >>>>> IIRC, we only have host mode enabled at present. So, yes, I'd >>>>> expect this port >>>>> to work in host mode currently without any issue. >>>>> >>>> >>>> Okay, so we have to decide whether it's reasonable to switch AC100 >>>> and TrimSlice >>>> to the peripheral mode. I think realistically chances that someone >>>> uses that >>>> port in a host mode are quite low, while it works fine and probably >>>> more useful >>>> in a device mode. >>> >>> Judging by this: >>> >>> http://trimslice.com/download/documentation/trim-slice-man.pdf >>> >>> at least TrimSlice doesn't seem to implement OTG, so we'd have to >>> make a >>> choice to support either host or peripheral mode. I guess technically >>> it >>> would need to be peripheral mode because pin 4 is not connected. >>> >>> Does a similar document exist for AC100? >> >> Judging by the Compal PAZ00 schematics it does indeed have an ID pin >> which is connected to the mini USB socket. >> >> USB1_ID1: From Connector >> >> USB1_ID2: From EC >> >> So an alternative possibility to switch device/host mode would be from >> the EC (;-p). > > According to the TRM, there's a USB PHY register that can be used to > query the ID/VBUS pins. They can optionally also be connected to a pair > of GPIO lines. Apparently it's even possible to hook them up to the PMU > and use a PMU specific mechanism. Most of that information can be found > in downstream kernel code. > > Using U-Boot I can monitor the USB1_IF_USB_PHY_VBUS_WAKEUP_ID_0 register > (address 0x7d000408) and I see that bit ID_STS changes, and can > presumably trigger an interrupt when ID_INT_EN is set. > > According to the downstream kernel this isn't supposed to work on the > Jetson TK1 up to and including the D revision, but it seems to work in > U-Boot at least on the C revision that I have. For earlier revisions > there is a sysfs attribute that can be used to force the port into the > desired mode. > > Can anyone check whether or not the above register (on Tegra20, the > physical address of the register should be 0xc5000408) changes when > switching between micro A and micro B cables on TrimSlice and/or > PAZ00? Note that I wasn't able to see a difference after unplugging a > micro B cable. It only toggles after plugging in the micro A or after > unplugging the micro B, which I think really only means that by default > the port will be in peripheral mode. This can probably also be > influenced by setting or clearing the ID_PU field (pull-up on ID pin). > > If this works reliably, we may be able to implement a very simple form > of detecting host/peripheral mode. According to the doc, the primary function of USB1 controller on TrimSlice is for USB-to-SATA. So I think micro USB there is intended for recovery mode only, in that case we should drop TrimSlice from the patchset. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
