Messages in this thread | | | Date | Sun, 14 Aug 2011 21:32:01 +0200 | Subject | Re: Driver framework: binding a driver to two devices? | From | Geert Uytterhoeven <> |
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On Sun, Aug 14, 2011 at 19:38, Greg KH <greg@kroah.com> wrote: > On Sat, Aug 13, 2011 at 10:44:42PM +0200, Geert Uytterhoeven wrote: >> As Amiga Zorro expansion boards have only one BAR (unlike PCI, which has >> multiple BARs), several Amiga graphics cards show up as two Zorro devices: >> one for the graphics memory and one for the graphics controller's registers. >> >> Traditionally, a driver for such a device used >> >> dev1 = zorro_find_device(id1, ...) >> dev2 = zorro_find_device(id2, ...) >> >> to find the two devices and match them. >> >> With the "new" driver framework, the matching with device id1 is now >> done using a >> struct zorro_driver with a table of IDs, while the matching with device id2 is >> still done by calling zorro_find_device(id2, ...). >> >> Recently (with cirrusfb) it turned out that the call to >> zorro_find_device(id2, ...) >> may fail to find the second device. I suspect this happens due to the second >> device haven't been probed for at the time the zorro_driver for the >> first device is >> initialized. >> >> I expect this can be fixed by delaying all calls to device_register() in >> amiga_zorro_probe() until all devices have been detected and added to the array >> used by zorro_find_device(). But I was wondering whether there's a more generic >> way in the driver framework to bind a driver to two devices? > > What you really want is the same "driver instance" bound to two devices, > right? That way the device would operate "knowing" about both physical > devices so as to properly control the thing.
Yes, that's what I want.
> Right now, no, there's not a simple way to do this with the driver > model. USB does this on its own for some devices that need to have > multiple "interfaces" (the USB equalivant for a "device") controlled at > the same time, so you might want to look at how that happens (in the > indivdual drivers, not in the USB core.)
Thanks, I'll have a look at the USB drivers. Do you know which examples to look at?
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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