USB multifunction

[Kay Sievers]

On Fri, 2004-08-13 at 20:32 +0200, David Zeuthen wrote:
> On Fri, 2004-08-13 at 19:30 +0200, Kay Sievers wrote:
> > What attributes we want for these devices besides the sysfs path and the
> > udev device node?
> > 
> 
> Well, just like we do for other class devices in the kernel, we want
> export properties about these on the hal device object representing the
> USB interface. So, I guess you need to look at what Linux driver gets
> bound to each USB interface

I can find 8 serial devices in sysfs, even when I don't have any. No
properties are exported. I can try to open the devices, to see if they
exist, hmm...

There are a few things for parallel ports in proc:
[kay at pim ~]$ tree /proc/sys/dev/parport/
  /proc/sys/dev/parport/
  |-- default
  |   |-- spintime
  |   `-- timeslice
  `-- parport0
      |-- autoprobe
      |-- autoprobe0
      |-- autoprobe1
      |-- autoprobe2
      |-- autoprobe3
      |-- base-addr
      |-- devices
      |   |-- active
      |   `-- lp
      |       `-- timeslice
      |-- dma
      |-- irq
      |-- modes
      `-- spintime

> write code to merge the properties you want
> (like e.g. serial_port.device), add the capability 'serial_port' and
> document this in the spec.

Yes, we can merge the sysfs links for the usb-adapter. The legacy
devices don't have anything.

> I would guess, looking from the picture of the device (there's a printer
> icon right next to the female DSUB25 connector) and your screenshot (it
> says USB Printing Interface which means that it's USB device class
> 0x07), that the usblp driver gets bound if you hotplug the adapter with
> a parallel port printer attached to the DSUB25 connector. Ideally, what
> we want is this hal device object to look no different that another USB
> printer.

Why should we merge the printer into the parallel interface? Isn't it a
system device by its own? Why not create a child for the printer, if we
find one? You can connect a lot of different devices to a parallel port.

Should we try to open all legacy devices (ttyS[0-7] par[0]) and put in
into the Computer if we get it opened?

Kay

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