From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754160Ab3ADE0k (ORCPT ); Thu, 3 Jan 2013 23:26:40 -0500 Received: from hqemgate03.nvidia.com ([216.228.121.140]:1648 "EHLO hqemgate03.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753854Ab3ADE0i (ORCPT ); Thu, 3 Jan 2013 23:26:38 -0500 X-PGP-Universal: processed; by hqnvupgp05.nvidia.com on Thu, 03 Jan 2013 20:26:33 -0800 Message-ID: <50E659F4.7020009@nvidia.com> Date: Fri, 4 Jan 2013 09:56:28 +0530 From: Prashant Gaikwad User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Stephen Warren CC: "mturquette@linaro.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-tegra@vger.kernel.org" Subject: Re: [PATCH v2 05/11] ARM: dt: tegra30: Add device node for APB MISC References: <1356619644-18565-1-git-send-email-pgaikwad@nvidia.com> <1356619644-18565-6-git-send-email-pgaikwad@nvidia.com> <50E4AE19.1060503@wwwdotorg.org> <50E520FC.4070805@nvidia.com> <50E5ADA6.1070904@wwwdotorg.org> <50E634D0.6080702@nvidia.com> <50E6470E.8090206@wwwdotorg.org> <50E64B18.8060806@nvidia.com> <50E653E3.5060901@wwwdotorg.org> In-Reply-To: <50E653E3.5060901@wwwdotorg.org> X-NVConfidentiality: public Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 04 January 2013 09:30 AM, Stephen Warren wrote: > On 01/03/2013 08:23 PM, Prashant Gaikwad wrote: >> On Friday 04 January 2013 08:35 AM, Stephen Warren wrote: >>> On 01/03/2013 06:48 PM, Prashant Gaikwad wrote: >>>> On Thursday 03 January 2013 09:41 PM, Stephen Warren wrote: > ... >>>>> OK. It sounds like we need a true APB MISC driver then, to abstract the >>>>> differences; the clock driver really shouldn't be touching the APB MISC >>>>> registers in all likelihood, unless a subset of the sections you >>>>> mention >>>>> above are truly dedicated to clock functionality. >>>> I don't think it is a good idea to create a driver for APB MISC, all >>>> registers are used by different drivers. >>> Well, it's even worse to have a bunch of other drivers randomly trample >>> on a set of registers they don't own. >>> >>>> Only chip id revision registers are used in clock driver. >>> There are already global variables exposed by the Tegra fuse driver; can >>> you just read those? >> It is not about variables or some value, we have to read some apb >> register to flush the write operation in apb bus before we disable >> peripheral clock. >> We are using chip id revision register for this purpose. > Ah. That's definitely not something the clock driver should be doing > directly. It's probably OK to add a custom Tegra-specific function to > some file in arch/arm/mach-tegra to implement this. Even better would be > a full bus driver for the APB bus, but that's probably too much bloat > for now. tegra_init_fuse in arch/arm/mach-tegra/fuse.c is already reading chip id revision register, so I can implement one function to read this register in fuse.c, which will be used by clock driver and tegra_init_fuse. But then we need to add it to some header file in include/mach or include/linux, where? any suggestion?