Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751820AbaFFMhC (ORCPT ); Fri, 6 Jun 2014 08:37:02 -0400 Received: from mail-ig0-f175.google.com ([209.85.213.175]:46950 "EHLO mail-ig0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751434AbaFFMhA (ORCPT ); Fri, 6 Jun 2014 08:37:00 -0400 Date: Fri, 6 Jun 2014 13:36:53 +0100 From: Lee Jones To: Mark Brown Cc: Grant Likely , "linux-arm-kernel@lists.infradead.org" , Linux Kernel Mailing List , Wolfram Sang , Linux I2C , "devicetree@vger.kernel.org" , Linus Walleij Subject: Re: [PATCH 7/7] OF/ACPI/I2C: Add generic match function for the aforementioned systems Message-ID: <20140606123653.GP24240@lee--X1> References: <1401883796-17841-1-git-send-email-lee.jones@linaro.org> <1401883796-17841-8-git-send-email-lee.jones@linaro.org> <20140605103009.85BE4C40A4D@trevor.secretlab.ca> <20140605103709.GE19550@lee--X1> <20140605155509.GH24240@lee--X1> <20140606102446.GK2520@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20140606102446.GK2520@sirena.org.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 06 Jun 2014, Mark Brown wrote: > On Thu, Jun 05, 2014 at 04:55:09PM +0100, Lee Jones wrote: > > On Thu, 05 Jun 2014, Grant Likely wrote: > > > > I still think the way to do it is to emulate the missing i2c_device_id > > > when calling the drivers .probe() hook by having a temporary copy on > > > the stack and filling it with data from the OF or ACPI table.... > > > That's the opposite of what I'm trying to achieve. I'm trying to get > > rid of unused i2c_device_id tables, rather than reinforce their > > mandatory existence. I think an i2c_of_match_device() with knowledge > > of how to match via pure DT principles (of_node/compatible) and a > > fall-back, which is able to match on a provided of_device_id table > > alone i.e. without the requirement of an existing of_node. > > > I've also been mulling over the idea of removing the second probe() > > parameter, as suggested by Wolfram. However, this has quite deep > > ramifications which would require a great deal of driver adaptions. > > If you're going to do that another option is to refactor the probe() > function to take the driver_data as an argument and then have the core > pass that from whatever table it matched from rather than the entire > i2c_device_id structure. That way the driver just needs to supply all > the ID tables mapping binding information to whatever it needs and the > core can pass in the driver data from whatever table it matched against. Unfortunately this means we're back to the aforementioned typing issue. For struct {platform,i2c,spi,acpi,etc}_device_id the driver data is a kernel ulong but the of_device_id's driver data attribute is a void*. I've just started work on a migration over to a new probe(). I don't think it's all that much work, but if there are any objections I'd prefer to hear them now rather than waste any time. I propose to convert a couple of drivers, one which doesn't use the driver_data and one that does, but is DT only and send them for review. See if Wolfram et. al like the method. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- 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/