Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932102Ab3IOMsQ (ORCPT ); Sun, 15 Sep 2013 08:48:16 -0400 Received: from cassiel.sirena.org.uk ([80.68.93.111]:38517 "EHLO cassiel.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755914Ab3IOMsM (ORCPT ); Sun, 15 Sep 2013 08:48:12 -0400 Date: Sun, 15 Sep 2013 13:47:44 +0100 From: Mark Brown To: Mika Westerberg Cc: Kevin Hilman , linux-i2c@vger.kernel.org, Wolfram Sang , "Rafael J. Wysocki" , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Lv Zheng , Aaron Lu , linux-arm-kernel@lists.infradead.org, Dmitry Torokhov , Mauro Carvalho Chehab , Samuel Ortiz , Lee Jones , Arnd Bergmann , Greg Kroah-Hartman , Liam Girdwood , Kyungmin Park Message-ID: <20130915124744.GW29403@sirena.org.uk> References: <1378913560-2752-1-git-send-email-mika.westerberg@linux.intel.com> <1378913560-2752-2-git-send-email-mika.westerberg@linux.intel.com> <87vc25pvvm.fsf@linaro.org> <20130913065434.GZ7393@intel.com> <87bo3whjz4.fsf@linaro.org> <20130913145022.GC7393@intel.com> <20130913173149.GE7393@intel.com> <87ioy4e8bw.fsf@linaro.org> <20130915064139.GJ7393@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="6lwf1fPv9TmaSLgy" Content-Disposition: inline In-Reply-To: <20130915064139.GJ7393@intel.com> X-Cookie: Your present plans will be successful. User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 94.175.92.69 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH v2 1/9] i2c: prepare runtime PM support for I2C client devices X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:57:07 +0000) X-SA-Exim-Scanned: Yes (on cassiel.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2534 Lines: 65 --6lwf1fPv9TmaSLgy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sun, Sep 15, 2013 at 09:41:39AM +0300, Mika Westerberg wrote: > There's also a less intrusive way of fixing the problem we see with ACPI > enabled I2C devices: > 1. In I2C core i2c_device_probe() we power on the I2C controller > and attach the client device to the ACPI power domain. Just like in > this patch but we don't touch the I2C client device runtime PM. > -> This should allow the existing drivers to keep using whatever > runtime PM strategy they have chosen. There should be no explicit need to power on the I2C controller if it's implemented the same way the existing ones are - just have it power itself on when it is doing a transfer. > 2. For ACPI enumerated I2C client devices drivers we need to > implement the runtime PM in order to save power (otherwise the > devices will be left powered on). > and do the same for SPI devices as well. > Then only thing that changes for non-ACPI devices is that the controller > will be powered on during the client device probe (well, and during > remove). > Thoughts? This is definitely less intrusive than the current proposal, there's one ACPI I2C device binding queued for -next after the merge window (rt5640) which will need an update. --6lwf1fPv9TmaSLgy Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.21 (GNU/Linux) iQIcBAEBAgAGBQJSNaxtAAoJELSic+t+oim9iGIP+gJNvCGQL2nGQa0PWny5Bj4Z omeCY4D3U/+1ClYHr5UfzoOMRhzlCsYwkLSYMz2Q8U+ce9zQq7SZjGxDdp6wKwfD NdtU6RUMoF/uQ31A20bhjnDIAjLi45ZHXICRnlzmlTCopD7bqhyvyaglKOQlJLp7 Xm4Yt8+j5GlLbDLNZXxqoS6rRDUzYFuuF77RBibI8e38iJi6IKCIQFTvlHWO1nI/ dbQJPjXBStreCcF74o8mBWxO9advbVZ3VBcsNiSkHJmnLJovcJbDNWC8Y4RebPL6 UDUj+jxPPVHRCCDBdNWKoSXl6yspTI30hKfO/RhwrbL0k+31Elx7orwwuYlf1715 LPGooEkJgjWANsZ3cqbm7fvVr7COC6ITBdErM78VKx6FkMJmMP2BeKV41o8FYpyh P0kt8IskoM/3HPOQFYR1Bpi4z6IEJkKLJ0hleclG9YFb4HHRAw99C5ITJz93wtpw kU7cyucXdhmH7IQFw2/3cwMnFYmcdOYKnneynMzi5wSe8sCx46ymgGiRkuf9yflW zNsDomePdmFNMGQ3uJCsRYjeFQkV0+2kl4J4KwQtV8SnZeukrokjZEQrbPm0Ckqt 8luGt9Kv6GoIhaLuwFGZd+0KyDyAYtZwUQA7GtWDDNs0Eb5rwLv+z9LlNC24cTZj jXKX948f8uDI8ctALQ0O =drge -----END PGP SIGNATURE----- --6lwf1fPv9TmaSLgy-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/