Date: Mon, 24 Nov 2008 09:52:36 +0100 From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> To: =?utf-8?Q?Rafa=C5=82?= Jaworowski <raj@semihalf.com> Cc: Nathan Whitehorn <nwhitehorn@freebsd.org>, freebsd-arch@freebsd.org Subject: Re: Enumerable I2C busses Message-ID: <86od054iaz.fsf@ds4.des.no> In-Reply-To: <C1917DFE-AA7F-4042-8A8F-088599FCDBB4@semihalf.com> (=?utf-8?Q?=22Rafa=C5=82?= Jaworowski"'s message of "Sun, 23 Nov 2008 21:18:54 %2B0100") References: <4929877B.6060307@freebsd.org> <86myfq9uha.fsf@ds4.des.no> <C1917DFE-AA7F-4042-8A8F-088599FCDBB4@semihalf.com>
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Rafa=C5=82 Jaworowski <raj@semihalf.com> writes: > Well, hard-coded addresses and conflicting assignments between vendors > do not technically prevent from scanning the bus; actually, our > current iicbus code can do bus scaning when compiled with a diag > define. I haven't looked at how that is implemented, but - I2C version 3 describes device enumeration and identification, but AFAIK very few devices actually support it. This is really stupid, BTW. Philips could easily have required the first few bytes of the device address space to contain a vendor / device ID, along the lines of PCI and USB, from the start. I wonder: did it not occur to them, or did they intentionally leave it out to save a few microcents per chip? DES --=20 Dag-Erling Sm=C3=B8rgrav - des@des.no
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