Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752920AbaAOSWP (ORCPT ); Wed, 15 Jan 2014 13:22:15 -0500 Received: from mail-oa0-f41.google.com ([209.85.219.41]:59810 "EHLO mail-oa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751754AbaAOSWL (ORCPT ); Wed, 15 Jan 2014 13:22:11 -0500 References: <1389743333-16741-1-git-send-email-marc.ceeeee@gmail.com> <1389743333-16741-8-git-send-email-marc.ceeeee@gmail.com> <201401151410.39112.arnd@arndb.de> Mime-Version: 1.0 (1.0) In-Reply-To: <201401151410.39112.arnd@arndb.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <61E0E2A7-F7FC-4397-8E92-06CC409912B9@gmail.com> Cc: Christian Daudt , Florian Fainelli , Matt Porter , Russell King , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" X-Mailer: iPhone Mail (11B554a) From: Marc Subject: Re: [PATCH v3 7/7] ARM: brcmstb: dts: add a reference DTS for Broadcom 7445 Date: Wed, 15 Jan 2014 10:22:07 -0800 To: Arnd Bergmann Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, Thank you for the suggestion - it's exactly what we were looking for! Regards, Marc Sent from my phone > On Jan 15, 2014, at 5:10 AM, Arnd Bergmann wrote: > >> On Wednesday 15 January 2014, Marc Carino wrote: >> + gen-ctrl { >> + compatible = "brcm,brcmstb-gen-ctrl-v1"; >> + reg = <0xf0404304 0x4 >> + 0xf0404308 0x4 >> + 0xf03e2578 0x4 >> + 0xf03e2488 0x10 >> + 0xf0452000 0x20>; >> + }; > > Sorry I didn't get back to you on this when we discussed the previous > version. I'm actually less happy with this DT representation than the > original. What I take from your description is that you have multiple > register ranges that basically combine more-or-less random registers > that belong into different Linux subsystems. > > I think the best way to deal with this is to have the "syscon" driver > handle the multiplexing between the various drivers that need access > to the registers. It would look something like (taking the numbers > from your previous patch): > > ahb { > ranges = <0 0xf0000000 0x1000000>; /* 16 MB remapped registers */ > > hif-cpubuictrl: syscon@3e2400 { > compatible = "brcm,7445-cpubioctrl", "syscon"; > reg = <0x3e2000, 0x1000>; > }; > > hif-continuation: syscon@45200 { > compatible = "brcm,7445-hif-continuation", "syscon"; > reg = <0x452000, 0x1000>; > }; > > sun-top-ctrl: ... > }; > > This lets the syscon driver find and map the three register areas. > Drivers that need access to the registers then do > > reset { > compatible = "brcm,7445-reset-ctrl"; > syscon = <&sun-top-ctrl 0x300 0x100>; > #reset-cells = <1>; > }; > > And then you can add a regular device driver to drivers/reset that provides > a device_reset() API to other drivers, or a system-reset function to be > registered as arm_pm_restart. This driver would use > syscon_regmap_lookup_by_phandle() to get access to a regmap pointer, > and then use either hardcoded offsets into the regmap, or get those > offsets from numbers in the devicetree, as provided in the example > above. > > Arnd -- 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/