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>
