Thanks - that's just what I was looking for.  I just wasn't sure if it was
"OK" to traverse the dv_parent link...

On Mon, 11 Aug 1997, Martin Husemann wrote:

> Paul Goyette wrote:
> 
> > So, given a pointer to the grf_softc for a particular grf, how can I
> > determine, in a supported way, if there is an ite attached to that grf?
> > Keeping in mind, of course, that an ite might be attached to any of
> > several grfs...
> 
> I'm no expert on this and don't know the Mac port, so just a few tries:
> 
> For frequent use: cast the "struct device *parent" passed to ite_attach
> to grf_softc and fill in a pointer to the ite_softc (initialized to NULL
> by grp_attach before)? Not good, if there's any chance of an ite attaching
> to something completely different. Not good information hidding, no clean
> encapsulation.
> 
> Do something like scsi device drivers do with scsibusses: the bus passes
> the address of a struct scsi_link to the attaching device, which fills in
> his adress?
> 
> For infrequent use (like yours sound) something like this?
> 
> static struct device *
> find_ite_at_grf(grf)
> 	struct device *grf;
> {
> 	struct device *dev;
> 	for (dev = alldevs.tqh_first; dev; dev = dev->dv_list.tqe_next)
> 		if (strcmp(dev->dv_cfdata->cf_driver->cd_name, "ite") == 0)
> 			if (dev->dv_parent == grf)
> 				return dev;
> 	return NULL;
> }
> 
> I hope this is OK, as I've just done something similar in my code over the
> weekend ;-)
> 
> 
> Martin
> 

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