From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967067AbbBDRra (ORCPT ); Wed, 4 Feb 2015 12:47:30 -0500 Received: from sauhun.de ([89.238.76.85]:33682 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966657AbbBDRr0 (ORCPT ); Wed, 4 Feb 2015 12:47:26 -0500 Date: Wed, 4 Feb 2015 18:47:23 +0100 From: Wolfram Sang To: Guenter Roeck Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] eeprom: at24: Add support for large EEPROMs connected to SMBus adapters Message-ID: <20150204174723.GB30930@katana> References: <1423067017-27607-1-git-send-email-linux@roeck-us.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="0ntfKIWw70PvrIHh" Content-Disposition: inline In-Reply-To: <1423067017-27607-1-git-send-email-linux@roeck-us.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --0ntfKIWw70PvrIHh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Feb 04, 2015 at 08:23:37AM -0800, Guenter Roeck wrote: > Large EEPROMS (24c32 and larger) require a two-byte data address > instead of just a single byte. Implement support for such EEPROMs > with SMBus commands. >=20 > Support has limitations (reads are not multi-master safe) and is slow, > but it works. Practical use is for a system with 24c32 connected to > Intel 82801I (ICH9). Can't you simply use i2c-dev to access the EEPROM? In multi-master environments, things can really go wrong, so I wouldn't like to add something dangerous by default. Maybe with a module parameter named "allow-multimaster-unsafe-access-to-large-eeproms-with-smbus" which is default off. But I'd really prefer the i2c-dev solution. Hooking a 16bit EEPROM to SMBus is daring, after all. SMBus is multi-master, too. --0ntfKIWw70PvrIHh Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJU0lsrAAoJEBQN5MwUoCm2VuYP/2DurOnQypsERp/NDUc2/0cB sR0xi/dPtFHP60ynTVJ3rmyJ1rlLAprDpSvdOLZm7AyeRqLa9BE0EDoILABwWADO zUDJd7OhfNsGRNWiFmXSxjPsSbU1ASHbjF3Np53Q8ISjZkogI+R0wjqXiW0P0/yk SHcmBu11r0Kj2W6iXToZxe0PP74QbDH4pT4nv5quIRJe6udJHkGaA/eI4K8/iUj9 KH8SvPZDfCb25bd/0ibMD6WlIMegmORpEjLUmiK9nZIVKA06Zv+LRNw2L59Q5lyf NosY6jFpI7b3WA/iGOvI1tABknCC5mIyO6E/kkNdPwEkec5qwra7OdPj1mysSY6N UH52QgQQ96AXPX60A4m8rKO1aLMlxjEuptnsEVqvcXBkntVMvEh6tcj49RW5CKMU JpiWfz3GM8BilmjYbW6uJVc1mz4qfXz+s3lfr8FoAmh6WseONDY2Gk3try95xQeH xoD91iSYhpnssgnwnfi0LX9mgsDzCvjkdcaVlt3rsvZs0Eb36IOVR/2Y7HCXCmLq TLkK61jyjSjFyhgvGDVv5+jHkiPTzMZ+BStciecELUBG+h0tFjXPybfscozR+HWp d3KuU8Bp6PrAFINrY75BeQfwfr/AQl+fKDKQaseSMLew5mMdPT4g/HKuRFu7otFb F0xqgB83m8dBH8Zua6S2 =3Y4M -----END PGP SIGNATURE----- --0ntfKIWw70PvrIHh--