From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rajeev kumar Subject: Re: About one i2c failure issue after system reset Date: Mon, 21 Nov 2011 15:49:49 +0530 Message-ID: <4ECA25C5.3010205@st.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Hui Cc: "ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org" , "khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org" , "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-i2c@vger.kernel.org Hello Jason On 11/21/2011 1:05 PM, Jason Hui wrote: > Hi, Ben, Jean, > > I have one issue about the i2c failure: there will be on-going i2c > transfer while system get reset. > At the time when the reset happens, the slave may pull the SDA to > LOW.After reset, the i2c master may reset, but > the slave may still pull the SDA to LOW since there is no reset pin > for the slave device to do i2c reset, thus > result in the further i2c access failure forever unless we completely > power off the system by pulling out > the battery. > This is not the only solution for this. Master can accomplishes error recovery by clocking Clock until Data is high and then issuing a Start followed by a Stop. Best Regards Rajeev ... > I know we have the shutdown member function, but as I know there is > very less i2c master has implemented this > function correctly. I think we need take seriously about this issue, > do you have any comments? Thanks, > > > Jason Liu > -- > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >