Re: [PATCH v2] char: xillybus: Add driver for XillyUSB (Xillybus variant for USB)

From: Greg KH
Date: Mon Feb 01 2021 - 09:27:00 EST


On Mon, Feb 01, 2021 at 04:16:51PM +0200, eli.billauer@xxxxxxxxx wrote:
> From: Eli Billauer <eli.billauer@xxxxxxxxx>
>
> The XillyUSB driver is the USB variant for the Xillybus FPGA IP core.
> Even though it presents a nearly identical API on the FPGA and host,
> it's almost a complete rewrite of the driver: The framework for exchanging
> data on a USB bus is fundamentally different from doing the same with a
> PCIe interface, which leaves very little in common between the existing
> driver and the new one for XillyUSB.

As this has nothing to do with the existing XillyBus code, and you
aren't doing anything "fancy" with the character device nodes, why does
this need to be a kernel driver at all? Why can't you just use libusb
and talk to the device directly from userspace with no kernel driver
needed?

And always cc: linux-usb@xxxxxxxxxxxxxxx when submitting a USB driver so
that the developers there can review it.

thanks,

greg k-h