From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: [RFC 1/5] ARM: at91: add general purpose backup register (GPBR) support Date: Mon, 8 Apr 2013 10:46:18 +0200 Message-ID: <20130408084618.GB25605@localhost> References: <20130407150938.GA25605@localhost> <1365347572-14972-1-git-send-email-jhovold@gmail.com> <20130408073329.GO20693@game.jcrosoft.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20130408073329.GO20693@game.jcrosoft.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Jean-Christophe PLAGNIOL-VILLARD Cc: Johan Hovold , dgilbert@interlog.com, Nicolas Ferre , Robert Nelson , devicetree-discuss@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Mon, Apr 08, 2013 at 09:33:29AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > On 17:12 Sun 07 Apr , Johan Hovold wrote: > > > > Add General Purpose Backup Register (GPBR) support. > > > > Most at91 SoCs have at least four 32-bit General Purpose Backup > > Registers (GPBR) powered by backup-power (VDDBU). One such register is > > currently used by rtc-at91sam9 driver to store the RTC time base. > > > > Make sure the registers are mapped by arch setup code and add generic > > accessors for in-kernel use. > > > > This is a step in adding device-tree support to the rtc-at91sam9 driver. > > > This is a regression > > we loose the tracking of what request and use the GPBR Implementing the GPBR accessors using a simple global resource was one quick way forward to decouple and generalise the GPBR. Of course, this could be turned into a more elaborate framework or driver where registers are requested and released by other drivers and possibly also by user-space. Thanks, Johan