From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Krufky Subject: Re: [PATCH 2/6]: i2c-pcf: Add adapter hooks around xfer begin and end. Date: Wed, 15 Oct 2008 17:37:41 -0400 Message-ID: <48F662A5.4050303@linuxtv.org> References: <20080821.024322.35962617.davem@davemloft.net> <20081015141914.7d6c3dd5@hyperion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081015141914.7d6c3dd5-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org> 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 Cc: David Miller , i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Jean Delvare wrote: > Hi David, > > On Thu, 21 Aug 2008 02:43:22 -0700 (PDT), David Miller wrote: > >> i2c-pcf: Add adapter hooks around xfer begin and end. >> >> Some I2C bus implementations need to synchronize with external >> entities, such as system firmware, which might also be programming the >> same I2C bus. >> >> In order to facilitate this add ->xfer_begin() and ->xfer_end() hooks >> which are invoked around pcf_xfer(). >> > > I get the idea, but I'm not sure about the implementation. I had a > request several months ago for something similar for the i2c-algo-bit > driver. I don't think we want to duplicate this mechanism in every > i2c-algo driver, so it would probably make sense to implement it > at the i2c-core level? > > Michael, do you still need this for i2c-algo-bit? We did not discuss > this again recently, so I admit I don't know what is the status of this > request. Jean, Yes, the problem still exists, and I still need a way to lock the i2c adapter during certain volitile operations at driver start-up. Right now I have an artificial delay in place as a workaround, but that's only because there currently is no other choice. Basically, I have a single piece of silicon that is capable of bringing down the entire i2c bus if somebody attempts to communicate with any other IC during initialization of this silicon. Regards, Mike _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c