From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: [PATCH] Add a new-style driver for most I2C EEPROMs Date: Mon, 14 Apr 2008 08:57:33 -0700 Message-ID: <200804140857.33732.david-b@pacbell.net> References: <1207914198-8561-1-git-send-email-w.sang@pengutronix.de> <20080414072227.GU13814@pengutronix.de> <20080414143925.31b55b39@hyperion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080414143925.31b55b39-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Errors-To: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org To: Jean Delvare , Wolfram Sang Cc: i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Monday 14 April 2008, Jean Delvare wrote: > > > To support the X24645, it would be necessary to raise AT24_MAX_CLIENTS > > > to 32 (what a beast!). Then again, most eeproms will just need one > > > client, so this would cause quite some overhead in most use-cases. > > > Maybe it pays off to hande this dynamically? > > > > As eeproms are normally slow things anyway, would it be a big > > performance impact? > > I agree that going dynamic makes sense. Not that it has anything to do > with the speed of EEPROMs though - the memory allocation will be done > at device initialization time, and after that dynamic or not should > perform just the same. Right. X24645 looks a bit more bizarre than any EEPROMs I had come across; it'll need some changes in chip config data. You'd think they'd just use two byte addressing! I guess doing it that way lets them use SMBus-only hosts. Wolfram's at24_ee_address() cleanup looked fine. The header looks OK, but I'd add a comment *encouraging* folk to double check those params for their chips, in particular to check the page size. It's OK if their chip has a bigger page size than those "defaults" although they could get faster write performance by listing the right value ... but it's NOT OK if their chip has a smaller write size than what's listed there, they'll lose data. I'll be glad to see this go upstream. :) - Dave _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c