From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH 2/3 V3] i2c: mxs: Rework the PIO mode operation Date: Fri, 4 Oct 2013 07:20:52 +0200 Message-ID: <20131004052052.GA3194@katana> References: <1380497035-7457-1-git-send-email-marex@denx.de> <1380497035-7457-2-git-send-email-marex@denx.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="OgqxwSJOaUobr8KG" Return-path: Content-Disposition: inline In-Reply-To: <1380497035-7457-2-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 --OgqxwSJOaUobr8KG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Sep 30, 2013 at 01:23:54AM +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 Please fix the checkpatch errors and build warning. --OgqxwSJOaUobr8KG Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJSTlA0AAoJEBQN5MwUoCm2k0oP/AmVjJ0Uk2rAkGd/s5smyEu8 G1eoXg0La9IvRQeqxYVtzo7ncKx5StA6MZm2s3nSbJzN8KhuloL8YhCj4F1QUYYs R3mZksRxdbb/HHmh2sb25H0hj5iAgX1RpLaNfdrGR2XnMtLVMYB4nktS5MAXvKfJ Qd3c1T6N5td+hZ00z+zS07PFUql/h/avkD008tOwTuc0vCiN5Mx/h5p9gtYUTDqS MYgdMc8AqwtZmP0FcAW/AioRtAQTAJRl01gNXxAptDSET4UJ/LZF0tqkMkKxsvik P0CoR0jlOxQPcMg0yXCS6t1ENK13okOSgjqqtvvSLMTE3TkcxAmdU1t/cpYIi3Uk 9XrpgrJDspAmQYKIlPd09NcrUdqhbDp8xQraXd3MueUlhtwf6p2u7Nnnupa8PnMe ZypD9bIwhOKrvodX/cvmHEyjYrfKqkny9Z8iDTehdHOzc6ElQ3/3kbG8j85CidhF fS66qSgfJfWpuPD77owZE1pUDmq67uoddgEZ/y8jhwh8m1yR9AULmlmDHos6ZPya v+H/I3g7lxm9Km74KJ3hr9KlcfLdb3/9YJuL1+NruAdYZ10s1KfKQsp46MoZpU7g gL6+GUQv0zFWXwOqrWaxBURLEsAwyiUaRwJFfL+gH7pQ7uWcBSL6xV6t6dlMiuGv oI4Ul6+yEJX+M3M2nS5e =IqXu -----END PGP SIGNATURE----- --OgqxwSJOaUobr8KG--