Thanks -- On Jul 21, 2011, at 3:18 PM, Michael wrote:
> Hello, > > On Thu, 21 Jul 2011 14:44:04 -0500 > Frank Zerangue <frank.zeran...@gmail.com> wrote: > >> /sys/device.h -- seems to indicate that a device driver can attach to >> multiple parent >> drivers (e.g. busses, controllers, ?) >> >> /* >> * Devices can have multiple configuration attachments if they attach >> * to different attributes (busses, or whatever), to allow specification >> * of multiple match and attach functions. There is only one configuration >> * driver per driver, so that things like unit numbers and the device >> * structure array will be shared. >> */ >> >> Does anyone know how this is done in practice? > > You split the driver in bus-dependent and bus-independent portions - the > former does stuff like match & attach, find and map registers etc., the > latter is the actual driver. There are plenty examples in the source tree: > - hme, gem exist as pci and sbus variants > - le, esp, com have lots of different bus backends ( Try to find a 1990s UNIX > workstation that has neither an le nor an esp. Suns used both as sbus > devices, others used their own buses or had them embedded in custom IO chips. > ) > - chipsfb and igsfb supports both pci and ofbus ( actually vlb with > OpenFirmware glue, see arch/shark/ofw/chipsfb_ofbus.c, igsfb_ofbus.c ) > > have fun > Michael > -- > Michael <macal...@netbsd.org>
