On Wed, Mar 20, 2013 at 11:04:14AM -0400, Alan Stern wrote: > On Wed, 20 Mar 2013, Sergei Organov wrote: > > > > > >> What is recomended driver to use for a USB device that provides just > > >> 2 bulk end-points, in and out, to create a TTY to talk to it? Exact > > >> data formats that are used are application-specific, so only generic IO > > >> TTY-alike device (with no control) is required from the kernel. > > >> Searching through the lists and Internet uncovered multiple posts of > > >> why "usbserial" is a wrong driver for this purpose, but nowhere did I > > >> find what the right alternative is. > > > > > what shows lsusb (e.g. what is TTY PID)? What is chip inside? Usually > > > the chips are either FTDI or something similar, and then ftdi driver > > > should work (coupled with right parameters for "unsuported" IDs - you > > > can then propose patch once you will see the device working). > > > > Thanks, but this is _not_ FTDI or any other widely-known device. It's not > > usb-to-serial converter or modem of any kind at all. Just a device to > > which one can talk over 2 USB bulk end-points, and I want to get a TTY > > to talk to it. Maybe some user-space alternative? > > For something like this, usb-serial may indeed be the best solution, > even though it has relatively low throughput. I don't think any of the > more specific drivers are suited to this protocol. Just for the record, there's really nothing wrong with the usb-serial throughput. The days of a single read and write urb are long gone (2.6.32 if I remember correctly). The reason why one shouldn't use the generic driver for a "real" usb-serial device is that you cannot control baudrates, etc, and of course that the device-driver matching isn't automatic. For a simple device without any control commands you could use the generic driver. However, if this is a device which is others may be interested in using, adding a simple wrapper with the device is the way to go. Have a look at drivers/usb/serial/zio.c driver for an example. Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
