From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH v2 1/2] i2c-mv64xxx: Fix timing issue on Armada XP (errata FE-8471889) Date: Wed, 19 Jun 2013 12:24:17 +0200 Message-ID: <20130619102416.GH2950@katana> References: <1371570024-11613-1-git-send-email-gregory.clement@free-electrons.com> <1371570024-11613-2-git-send-email-gregory.clement@free-electrons.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="l06SQqiZYCi8rTKz" Return-path: Content-Disposition: inline In-Reply-To: <1371570024-11613-2-git-send-email-gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Gregory CLEMENT Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jason Cooper , Andrew Lunn , Thomas Petazzoni , Ezequiel Garcia , Sebastian Hesselbarth , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Zbigniew Bodek List-Id: linux-i2c@vger.kernel.org --l06SQqiZYCi8rTKz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 18, 2013 at 05:40:23PM +0200, Gregory CLEMENT wrote: > From: Zbigniew Bodek >=20 > All the Armada XP (mv78230, mv78260 and mv78460) have a silicon issue > in the I2C controller which violate the i2c repeated start > timing. The I2C standard requires a minimum of 4.7us for the repeated > start condition whereas the I2C controller of the Armada XP this time > is 2.9us. >=20 > So this patch adds a 5us delay for the start case only if the > mv64xxx_i2c_errata_delay flag is set. You are correct that this does not need a seperate property since this is a flaw of this specific controller. So, it needs a new compatible entry ('mv78230-i2c' for example) and this entry should then have the workaround enabled. Thanks, Wolfram --l06SQqiZYCi8rTKz Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJRwYbQAAoJEBQN5MwUoCm2kQUP/jE/YTwnSPubM1CLW5vCJkvB CVDfBZzCcs2ZcIdeqfQSWLk+bALL0mNOFcgY5ex7JMRcxKTv7I+/ksCx8j/8GRHv osm/7HDwIdy4aErsaRCNkc9Z0+yaA0CNhlQn6NxIANRv9/S7q2mBdYqvMROclHdS LZtfDJhqyRBE/g6XubjRM4VjKVUyXxuogEpLxWxoViUZOSkt7oL+K2cGlUyy21tl fjtYBcuDZ/iXCtXl9KILPdUKMQVR7JsJYcao0LQNUNeWfLDNLyCV3EaHbzzEfQTc LmZ0cg6X6Ye952/8twN9hul+QpjFqHPut/s8Ow9xiT31riew26BgkadAKqfN2it8 nMWK5tPMRGUMGXS1skiC2IgUO53ZGzbnth11Uq2pDxv7983Uboo/o8fyK/5dvFBP DTwqxrTrv/pm8GFsNau3HDfk+iSQHENvM1mn+EZahtBmLwkzKg6zYz8YaJRPc/67 GSrtvSDdsFR5ztucuXn/ez4ZmxBoAKEQMaBH0NZaGiYOj3z4ns6IeB0YRsAwMzPA 8pNUL7k4dQcfUJJ0q7TVSG5ReMpC9ZHviDoA1FzLHZ+62+3c4wUz79xOh3xHiCa5 lNmJMNA+QtRjHZQJIIYDSS+04/R3GDIkVuGD7W2XuO2Plucb9JtEakct+aYkeTGe SFb0nCkyF+CdcStKZLwI =5O5+ -----END PGP SIGNATURE----- --l06SQqiZYCi8rTKz--