On Thu, May 26, 2016 at 05:40:00PM +0200, Thierry Reding wrote: > From: Thierry Reding <treding@xxxxxxxxxx> > > All Tegra SoC generations from Tegra20 through Tegra124 have a ChipIdea > USB device controller. This set of patches adds very rudimentary support > for it to the existing ChipIdea driver and enables them on the set of > boards that I could easily test on. > > I'm sending this out as RFC because I'm not sure yet how to merge this. > While the driver seems to work fine (tested by exporting a USB driver or > eMMC via the mass storage function) I don't yet understand how to make > the driver switch between host and device modes dynamically. It might be > useful to get this merged before, but I'd like to have some feedback on > this, because doing so would mean that we need to use device mode on the > devices where it's enabled and can't use the USBD port in host mode. > Chipidea driver supports many ways to switch between host and device mode. It can support switching with/without disconnecting cable. Most of cases need to disconnect cable (Micro-AB) to switch between host and device mode, I just take this as an example: Using ID pin which is at Micro-B receptacle on the board to determine host (ID = 0) or device (ID = 1 )mode. - ID pin connects to CPU, and ID interrupt and value can be get through register OTGSC. - ID pin does not connect to CPU, and there is a dedicated GPIO for ID. -- Best Regards, Peter Chen -- 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
