From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: status of i2c-cpm and ds2482 Date: Sat, 9 Jan 2010 09:12:25 +0100 Message-ID: <20100109091225.59746b62@hyperion.delvare> References: <20100108020253.GJ3388@radix50.net> <4B471647.8050806@scram.de> <20100108121723.GD4004@radix50.net> <20100108135222.49d7b834@hyperion.delvare> <20100108140111.GF4004@radix50.net> <4B473BCE.8060803@scram.de> <20100108231942.GA3699@radix50.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100108231942.GA3699-Y2X99Y6vBNTR7s880joybQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Baurzhan Ismagulov Cc: Jochen Friedrich , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hi Baurzhan, On Sat, 9 Jan 2010 00:19:43 +0100, Baurzhan Ismagulov wrote: > On Fri, Jan 08, 2010 at 03:06:06PM +0100, Jochen Friedrich wrote: > > I2C0: i2c@860 { > ... > > w1@aa { > > reg = <0xaa>; > > compatible = "dallas,ds2482"; > > }; > > }; > > This worked, thanks much Jochen and Jean! > > I had to use "reg = <18>;", it didn't build with "0x". > > FWIW, I've also tried restoring 0x18 in normal_i2c in ds2482.c, and > i2c-core complained about quick not being supported. Restoring? 0x18 has never been in ds2482's normal_i2c list. > Where can I read about what it is? As I2C doesn't offer any standard way to detect device presence at a given address, we (ab)use the SMBus "Quick command" (0-byte message) for this purpose. Not all adapters support this type of transaction. > Why is it now required, whereas this worked in 2.6.25.7? The i2c-cpm driver was not present in kernel 2.6.25.7, so you must have been using an out-of-tree driver. Maybe that driver had (possibly fake) support for the SMBus quick command. -- Jean Delvare http://khali.linux-fr.org/wishlist.html