From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCH] i2c: i2c_mxs: Set ACK_MODE bit Date: Thu, 15 Aug 2013 23:30:49 +0200 Message-ID: <201308152330.50058.marex@denx.de> References: <1372780860-12972-1-git-send-email-fabio.estevam@freescale.com> <20130815100809.GE2987@katana> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130815100809.GE2987@katana> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: Fabio Estevam , shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, cb-/RsSufbtIHM@public.gmane.org List-Id: linux-i2c@vger.kernel.org Dear Wolfram Sang, > On Tue, Jul 02, 2013 at 01:01:00PM -0300, Fabio Estevam wrote: > > According to mx23 erratum 2727: > > > > "2727 : I2C 9th Clock Pulse (ACK) not generated when RETAIN_CLOCK set. > > > > Description: > > > > When RETAIN_CLOCK is set, the ninth clock pulse (ACK) is not generated. > > However, the SDA line is read at the proper timing interval. If > > RETAIN_CLOCK is cleared, the ninth clock pulse is generated. > > Also, the HW_I2C_VERSION register incorrectly states the version is 1.2. > > It should be 1.3. > > > > Workaround: > > HW_I2C_CTRL1[ACK_MODE] has default value of 0. It should be set to 1 to > > enable the fix for this issue." > > > > It has also been noticed that mx28 needs to implement this fix in order > > to have SMBus to work properly. > > > > Reported-by: Christoph Baumann > > Signed-off-by: Fabio Estevam > > What's with this one? Bogus? Needed? Still needed after PIO rework? I dont think this is needed on MX28 as this is set by default. On MX23, I dont see any difference with this enabled/disabled. Best regards, Marek Vasut