Date: Wed, 6 Aug 2003 12:40:01 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: ticso@cicely.de Subject: Re: How to get a device_t Message-ID: <20030806104001.GD32228@cicely12.cicely.de> In-Reply-To: <40313.1060165108@critter.freebsd.dk> References: <20030806101148.GC32228@cicely12.cicely.de> <40313.1060165108@critter.freebsd.dk>
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On Wed, Aug 06, 2003 at 12:18:28PM +0200, Poul-Henning Kamp wrote: > In message <20030806101148.GC32228@cicely12.cicely.de>, Bernd Walter writes: > >I need to add I2C support for a Elan520 based soekris system. > >The system has the required GPIO pins and there is the iicbb driver > >to handle generic bitbang code - just needing a simple layer driver to > >enable, disable and read pins. > >But unlike normal isa/pci hardware probing the existence of the GPIO > >line is a bit difficult. > >The current elan-mmcr.c gets started from i386/pci/pci_bus.c at > >host bridge probing, because that's seems to be the only place to > >safely detect this special CPU. > > That's my doing, based on my reading of the datasheet from AMD. > > It would be better if we could detect the Elan in the normal CPU > identification stuff, but I couldn't seem to find a reliable way. I could reread the datasheet, but don't give it much hope if you hadn't find anything usefull. > >>From the logicaly standpoint the extensions had to be attached to > >nexus, but nowhere is the current code path there is a handle for > >nexus or any other device_t. > > In fact what you may want to do is hang the entire MMCR off the nexus > as a bus, and hang the various drivers off that bus. What needs to be in *_probe() to conditionalize on elan existence? -- B.Walter BWCT http://www.bwct.de ticso@bwct.de info@bwct.de
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