From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH 2/3 V4] i2c: mxs: Rework the PIO mode operation Date: Sun, 6 Oct 2013 15:51:35 +0200 Message-ID: <20131006135135.GB4173@katana> References: <20131004052052.GA3194@katana> <1381060933-11111-1-git-send-email-marex@denx.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="MfFXiAuoTsnnDAfZ" Return-path: Content-Disposition: inline In-Reply-To: <1381060933-11111-1-git-send-email-marex-ynQEQJNshbs@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Marek Vasut Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Alexandre Belloni , Christoph Baumann , Fabio Estevam , Shawn Guo , Torsten Fleischer List-Id: linux-i2c@vger.kernel.org --MfFXiAuoTsnnDAfZ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Oct 06, 2013 at 02:02:13PM +0200, Marek Vasut wrote: > Analyze and rework the PIO mode operation. The PIO mode operation > was unreliable on MX28, by analyzing the bus with LA, the checks > for when data were available or were to be sent were wrong. >=20 > The PIO WRITE has to be completely reworked as it multiple problems. > The MX23 datasheet helped here, see comments in the code for details. > The problems boil down to: > - RUN bit in CTRL0 must be set after DATA register was written > - The PIO transfer must be 4 bytes long tops, otherwise use > clock stretching. > Both of these fixes are implemented. >=20 > The PIO READ operation can only be done for up to four bytes as > we are unable to read out the data from the DATA register fast > enough. >=20 > This patch also tries to document the investigation within the > code. >=20 > Signed-off-by: Marek Vasut Applied the series to for-next, thanks! > (and fixed my local pre-commit hook) Yay :) --MfFXiAuoTsnnDAfZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJSUWrnAAoJEBQN5MwUoCm2VYgP/0mQE9sjxUCWRCuC9PiO+zi7 8aaeq8li5FNALo+xO7maVAUVgpcfVNXiWjgFSQamTo+BE0LRmzOciWIFcP7munAB lhb9GpBTQ103979NcLigiAu4BLsxPWyrX3EdTTtxLqRMKVGdXClHW0LVUBwApL8/ VLko+gXMb4BgJRKizOoybkCYIjhJS9ftQpg5MH38hLWsERCxZkGopRgSpJ84Azvu WuWnoAPyVk399W80IW7YnWlwpFVZryADv9KOIxD5QsI4moTmS9XF+KbHtZSjtaPJ GqjcCKw0v34Tjoen9ffUQ6E23ntXGL9F+6vv5IDoCoSrByROTlXyct+tsMo6+SFZ 1+rgv+jxQ5wDaHqqGssbZaU4fYuAP2DmNUzYFyJdwDIZGVFH78Ti3UYtGOiom6vU LP8TlCBHWj31z8wXdD5oezlFff5kxVsqGa8S6VUUgcdJ9Aw0mvPhIeSUOhuKLCtJ luENAZakyVZexe5VRBEAft7im7AkEEai2cAcoVAgFj/e35d/hGcYoercUI/DdqKp xaVj3n1dW+XDvFpW3E+BoR70DbfHtP9e99Qb34VuKm8yhva3lWy6wtpVzqG2+EFR /2dxlxXhlpr4+6A+/4nb0dIS9ADcjyNx8BaxwA0aWiGnBIE4zfiqYtmY+3x2RBin qtUZ9nOIXB+LxxxIIuUO =VXKl -----END PGP SIGNATURE----- --MfFXiAuoTsnnDAfZ--