On Wed, Mar 22, 2017 at 11:19:10AM +0100, Greg Kroah-Hartman wrote: > On Wed, Mar 22, 2017 at 02:26:52AM -0700, Greg Hazel wrote: > > Hi, > > > > I’m working with Greybus and I’m wondering if there’s any support or > > code for virtual USB devices. > > Yes, the USB virtual controller driver is in the kernel, but you need to > have it enabled in your firmware as well, as it passes USB commands from > the kernel down to the firmware and then USB device directly. The driver that's merged is far from complete I'm afraid. There was some development happening out of tree, but the effort was discontinued and the work in progress never merged back. > Note, there are some limits on the size of a USB transaction at the > moment, we never got the chance to fix them up, but small transactions > (like a keyboard), should work fine. Once you start to get up to 4kb in > a transaction, you might have firmware issues. That would even be 2k, and you'd still need the out-of-tree driver... > > On one side of Greybus I have a small nuttX environment with a UART > > connected device which I can write modules for, and on the other side > > of Greybus I’d like to provide a network interface. I can’t modify > > that side, so I have to work with the kernel modules it has available. > > I thought it might be possible to present a virtual USB CDC-EVM to > > Greybus, and my guess (hope) is that cdc_ether would pick it up on the > > other side. > > Ah, if this isn't really a network device, or modem, I wouldn't mess > with cdc-evm. If it is a modem, then it should "just work" with the > uart code today, just tell userspace this is a modem and all should be > fine. Indeed, that would be the way to go. Johan _______________________________________________ greybus-dev mailing list greybus-dev@xxxxxxxxxxxxxxxx https://lists.linaro.org/mailman/listinfo/greybus-dev
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