From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCH] i2c: i2c_mxs: Set ACK_MODE bit Date: Wed, 3 Jul 2013 15:20:53 +0200 Message-ID: <201307031520.53637.marex@denx.de> References: <1372780860-12972-1-git-send-email-fabio.estevam@freescale.com> <20130702181115.GR27010@pengutronix.de> <51D31FD1.4080002@freescale.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <51D31FD1.4080002-KZfg59tc24xl57MIdRCFDg@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Fabio Estevam Cc: Uwe =?iso-8859-1?q?Kleine-K=F6nig?= , wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, 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, festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org List-Id: linux-i2c@vger.kernel.org Dear Fabio Estevam, > Hi Uwe, >=20 > On 07/02/2013 03:11 PM, Uwe Kleine-K=F6nig wrote: > > On Tue, Jul 02, 2013 at 01:01:00PM -0300, Fabio Estevam wrote: > >> According to mx23 erratum 2727: > >>=20 > >> "2727 : I2C 9th Clock Pulse (ACK) not generated when RETAIN_CLOCK = set. > >>=20 > >> Description: > >>=20 > >> When RETAIN_CLOCK is set, the ninth clock pulse (ACK) is not gener= ated. > >> 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 i= s 1.2. > >> It should be 1.3. > >>=20 > >> Workaround: > >> HW_I2C_CTRL1[ACK_MODE] has default value of 0. It should be set to= 1 to > >> enable the fix for this issue." > >>=20 > >> It has also been noticed that mx28 needs to implement this fix in = order > >> to have SMBus to work properly. > >>=20 > >> Reported-by: Christoph Baumann > >> Signed-off-by: Fabio Estevam > >=20 > > Did you see this making the driver handle some situations that caus= ed > > failure before? >=20 > No, I haven't. I saw the report from Christoph in the linux-arm-kerne= l > mailing list: > http://marc.info/?l=3Dlinux-arm-kernel&m=3D137277422127826&w=3D2 >=20 > And thought it could be nice if we could get it fixed for mx23 and mx= 28. How/when does this error manifest on the scope/LA? Best regards, Marek Vasut