From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752650Ab1HPNik (ORCPT ); Tue, 16 Aug 2011 09:38:40 -0400 Received: from moutng.kundenserver.de ([212.227.17.9]:63968 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752343Ab1HPNii convert rfc822-to-8bit (ORCPT ); Tue, 16 Aug 2011 09:38:38 -0400 From: Arnd Bergmann To: Mark Brown Subject: Re: [RFC PATCH] slimbus: Linux driver framework for SLIMbus. Date: Tue, 16 Aug 2011 15:37:28 +0200 User-Agent: KMail/1.12.2 (Linux/2.6.35-22-generic; KDE/4.3.2; x86_64; ; ) Cc: Kenneth Heitke , davidb@codeaurora.org, bryanh@codeaurora.org, linux-arm-msm@vger.kernel.org, Sagar Dharia , rdunlap@xenotime.net, rmk+kernel@arm.linux.org.uk, john.stultz@linaro.org, akpm@linux-foundation.org, ohad@wizery.com, gregkh@suse.de, stefanr@s5r6.in-berlin.de, lethal@linux-sh.org, linville@tuxdriver.com, zajec5@gmail.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <1313019091-15354-1-git-send-email-kheitke@codeaurora.org> <201108111455.56319.arnd@arndb.de> <20110812164608.GC28150@sirena.org.uk> In-Reply-To: <20110812164608.GC28150@sirena.org.uk> MIME-Version: 1.0 Content-Type: Text/Plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Message-Id: <201108161537.28612.arnd@arndb.de> X-Provags-ID: V02:K0:Z1ewSDEFV34FxCBm+HS2VZHAvQmvlE8e0NkiW5V7V5g Of2V9oesx7+hNqkQTFIQEMxEPe38ZrMvSCeUx8dyROqIWQPh0I kFcPU0eViV38EFrnrk4WeL9eLA9FFT5Y0UamIfzi/URHAbYzeh d38X1b0MnxPmWLZQfHQJ7us9pCg0lJjpVGHDxWVEU5TPhBG+QK yfQay8885sKwV4pnQ0xDA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 12 August 2011, Mark Brown wrote: > On Thu, Aug 11, 2011 at 02:55:55PM +0200, Arnd Bergmann wrote: > > On Thursday 11 August 2011, Kenneth Heitke wrote: > > > > +EXPORT_SYMBOL_GPL(slim_add_device); > > > I don't think this should be exported: AFAICT, the set of slim_devices > > is a property of the platform, so I don't see how any other device driver > > would add another device. > > The platform may be comprised of multiple hardwaare modules with > functionality on daughtercards which can be probed at runtime. You may > also find someone constructing a PCI card or something with a slimbus > controller on it at some point. This is theoretically true, but IIRC David mentioned that the bus is only present on few SoCs and has since been abandoned in favor of standard busses for new devices. > > > +EXPORT_SYMBOL_GPL(slim_register_board_info); > > > We are trying to gradually convert platforms that have hardcoded device > > lists and cannot probe devices by looking at the hardware over to using > > device tree files that list all the devices. > > > I think that this would work well for slimbus and should be done > > right from the start. This means however that you should not > > register a "board_info" but instead change the slim_register_controller > > function so that it adds all devices listed as children of the > > controller in the device tree. > > It seems a bit extreme to prevent anyone implementing a subsystem for > their platform until they've converted it into device tree. Though with > slimbus it should be at least somewhat probeable IIRC? >>From what I've heard (and seen in the code), there is no support for probing, just like in I2C. The platform is in the process of getting converted to device tree already, the first patches were posted on Saturday. I don't know what the timeline is for this, or how many board with slimbus are supported in mainline or still waiting to get merged, but my guess is that the bulk is still out of tree. If that's true, it's definitely cleaner to convert it over to device tree before merging, instead of having to change all the board files again when doing the conversion. Arnd