Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754196Ab1CKXkF (ORCPT ); Fri, 11 Mar 2011 18:40:05 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:38149 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752390Ab1CKXkA convert rfc822-to-8bit (ORCPT ); Fri, 11 Mar 2011 18:40:00 -0500 MIME-Version: 1.0 In-Reply-To: <4D7AA674.2050705@linaro.org> References: <4D79F068.2080009@linaro.org> <4D7AA674.2050705@linaro.org> From: Grant Likely Date: Fri, 11 Mar 2011 16:39:39 -0700 X-Google-Sender-Auth: pvwqnk_9WhFDn1HcCahHbIZLQO8 Message-ID: Subject: Re: RFC: Platform data for onboard USB assets To: andy.green@linaro.org Cc: Andy Green , Linux USB list , lkml , Benjamin Herrenschmidt , Arnd Bergmann , Greg Kroah-Hartman Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1480 Lines: 40 On Fri, Mar 11, 2011 at 3:47 PM, Andy Green wrote: > On 03/11/2011 10:45 PM, Somebody in the thread at some point said: >> >> On Fri, Mar 11, 2011 at 2:50 AM, Andy Green ?wrote: >>> >>> Hi - >>> >>> platform_data is a well established way in Linux to pass configuration >>> data >>> up to on-board assets from a machine file like mach-xyz.c. ?It's also >>> supported to pass platform_data up to devices that are probed >>> asynchronously >>> from busses like i2c as well, which is very handy. >>> >>> However AFAIK it's not possible to bind platform_data to probed USB >>> devices >>> as it stands. >> >> Oh, please no. >> >> platform_data is an ugly non-type-checked anonymous pointer. ?If you >> need to pass data to a driver, use something better designed. ?A >> device tree fragment would work, or provide some kind of query api. >> platform_data is definitely the wrong approach. > > $ grep platform_data drivers/* -R | wc -l > 2110 I'm not disputing that it is widely used; and it does make a certain amount of sense for static device registrations, but it is not a nice interface, and it is a horrible idea for dynamic devices. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. -- 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/