On Wed, Aug 15, 2018 at 10:56:47PM -0700, Patong Yang wrote: > Greg, > > Please see my response inline below. > > Patong > > > But there is a bigger problem here: > > > > > + xrusb_tty_driver = alloc_tty_driver(XRUSB_TTY_MINORS); > > > + if (!xrusb_tty_driver) > > > + return -ENOMEM; > > > > Why are you not using the usb serial core here? You need to do that, > > not try to provide your own custom tty driver. That way userspace > > programs will "just work" with your new device, no changes needed as > > your major/minor number and device name would be custom only for your > > device, which is not acceptable. > > The MaxLinear/USB serial devices support the CDC-ACM commands. > Therefore, we used the cdc-acm driver instead of the usb serial driver > as the starting point for developing the driver. We replaced "ACM" > with "XRUSB" throughout the driver. Would it be better if we just used > the same major/minor number as the CDC-ACM driver since it was based on > the cdc-acm driver? No, just use the cdc-acm driver itself and add your product/device id to it and it should work just fine. Why do you need to write a whole new driver at all? thanks, greg k-h
