From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752803AbbCEWKJ (ORCPT ); Thu, 5 Mar 2015 17:10:09 -0500 Received: from down.free-electrons.com ([37.187.137.238]:33346 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751378AbbCEWKE (ORCPT ); Thu, 5 Mar 2015 17:10:04 -0500 Date: Thu, 5 Mar 2015 23:08:01 +0100 From: Maxime Ripard To: Wolfram Sang Cc: Chen-Yu Tsai , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-sunxi@googlegroups.com, Hans de Goede , Arnd Bergmann Subject: Re: [PATCH v2 1/4] i2c: sunxi: Add Reduced Serial Bus (RSB) support Message-ID: <20150305220801.GE4522@lukather> References: <1425284686-5116-1-git-send-email-wens@csie.org> <1425284686-5116-2-git-send-email-wens@csie.org> <20150304172710.GA884@katana> <20150305182817.GB4911@lukather> <20150305184044.GA881@katana> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vv4Sf/kQfcwinyKX" Content-Disposition: inline In-Reply-To: <20150305184044.GA881@katana> 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 --vv4Sf/kQfcwinyKX Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 05, 2015 at 07:40:44PM +0100, Wolfram Sang wrote: >=20 > > > I don't have the bandwidth for a full review right now. However, I > > > already wanted to tell you guys that my gut feeling is that this > > > protocol is quite far away from I2C. P2WI was already at the edge. > > > Maybe there is a better place for such custom stuff? I dunno yet. > >=20 > > That's unfortunate, especially since it looks closer to SPI than what > > P2WI even was. >=20 > SPI? I assume you mean I2C. Can you elaborate your reasoning? Yeah, I obviously meant I2C, sorry. P2WI had no address. It was a single-device bus. However, the way it communicated with the device was very close to I2C, apart from a parity bit instead of the ACK. =46rom that regard, RSB is a multiple device bus, using addresses, just like I2C. The way it communicates is basically the one used by P2WI. So really, it just is more I2C-alike than P2WI has ever been. > > What would be your suggestion? >=20 > Let me quote: >=20 > "I don't have the bandwidth for a full review right now... I dunno > yet." Good thing that we are not talking about a full review then, but more a philosophical discussion. Thanks! Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --vv4Sf/kQfcwinyKX Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJU+NPBAAoJEBx+YmzsjxAgwQsP/0qHvSFthd6lON8KruXB0x7w 0P7aRcsx0wWCnOEpsNdOBWDNZuaJ42oxYjrwxcgzYCfGx+bJqNjvajtYLlu0vWnZ t0QofweIhpO/eRSN2puMRETvJJDNVfwy0lQkObdlsITqxWE4tYSfy6yhTp7onSnP hhLfpl2p4qaE3IGaFt2pRANlI+cktxcBSIaKWlKRDig9xZehNn/hBiNPVqcM5Ybg FWDJTkjuJqxwEevZmxzL5Wn17+MewGzUPPDiA2epQDmXnPGXHP3ZRwEGltN4wr6S H1jLQozWAzfeIqGKO+HY6gyxlJO7da3ECzOXmp2CMPzkrRWKW9B8HXvEfxazSkc0 X9WD7HxSR73Iln1UFFZpyj5lFCXh45hP8zAWC0meHz/BA4aPj9gimyEjaMv1BI3g WEBAWLTzKSBk57bwQFC0Wv/82jEuPad/rOMyAWG/Uf1QWoVgX6MxXG0Tsu5MwRg9 ypEfXzpLIbpb7PU6U1MmuHhyUve20YYjecrDPNhpSVnDSAszpSn10tUZz7krJBuZ drYNY4JaHbsYHgQF+XHdhUNfL/QiWv4Vb6NSkQdDBqBmwdRZAkh/PC4brsdqVmW6 18vJ6/4NV/c/Z+e/7ajbNvzIRcUszWrMFm+LQuNtGlGwWwMvLGzbzoL7jrduDeKd Gm9Sa9Syya7cwt7+yc2p =b22k -----END PGP SIGNATURE----- --vv4Sf/kQfcwinyKX--