Messages in this thread | | | Date | Thu, 18 Nov 2010 12:02:30 -0800 | From | Greg KH <> | Subject | Re: How do I choose an arbitrary minor number for my tty device? |
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On Thu, Nov 18, 2010 at 01:35:33PM -0600, Timur Tabi wrote: > Greg KH wrote: > >> I just booted a Linux kernel with the driver I just emailed you, and there's no > >> > /dev/serial/ directory. The only directories under /dev/ are 'shm' and 'pts', > >> > both of which are empty. > > > Then plug in a serial port device and see what happens. You didn't hook > > everything up in your driver correctly it seems, do your devices show up > > under /sys/class/tty? > > If I delete the call to device_create() in ehv_bc_init() (so that it creates the > TTY devices only, and not the character devices), I get this: > > # ls -l /sys/class/tty/ttyEHV* > lrwxrwxrwx 1 root root 0 Jan 1 00:04 /sys/class/tty/ttyEHV0 > -> ../../devices/virtual/tty/ttyEHV0 > lrwxrwxrwx 1 root root 0 Jan 1 00:04 /sys/class/tty/ttyEHV1 > -> ../../devices/virtual/tty/ttyEHV1 > lrwxrwxrwx 1 root root 0 Jan 1 00:04 /sys/class/tty/ttyEHV2 > -> ../../devices/virtual/tty/ttyEHV2 > > >> > I'm also running a Fedora 13 x86 system, just to see if I need a full modern OS > >> > to see these files. Again, there is no /dev/serial/, even though I have serial > >> > ports. > > Dynamic ones like a usb to serial device? > > No, not dynamic ones. > > >> > Also not that since I'm not registering the byte channels as serial devices, I > >> > wouldn't expect anything in /dev/serial/ to reference them. > >> > > >> > What does my driver need to do in order for these /dev/xxxx/ entries to contain > >> > that information? > > > See the udev rules for details. > > udev rules still need some way for the driver to tell user-space that > /dev/ttyEHV0 is associated with byte channel handle 73. I still don't know what > mechanism my driver is supposed to use to make that information available to > user space. > > I could fake it by doing this: > > for (i = 0; i < num_byte_channels; i++) { > bc->handle = get_the_byte_channel_handle(i); > ehv_bc_driver->name_base = bc->handle - i; > tty_register_device(ehv_bc_driver, i, NULL);
Why are you not setting up a parent device of your tty device? That should be essencial.
> } > > This actually works and does what I want, but I seriously doubt it's acceptable. > When I do this, I get: > > # ls -l /dev/ttyEH* > crw-rw---- 1 root uucp 253, 0 Jan 1 00:00 /dev/ttyEHV73 > crw-rw---- 1 root uucp 253, 1 Jan 1 00:00 /dev/ttyEHV76 > crw-rw---- 1 root uucp 253, 2 Jan 1 00:00 /dev/ttyEHV79
Does that work for you? Looks fine to me :)
But again, you really should get the driver model portion right...
thanks,
greg k-h
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