From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Christophe PLAGNIOL-VILLARD Subject: Re: [RFC 1/5] ARM: at91: add general purpose backup register (GPBR) support Date: Mon, 8 Apr 2013 12:04:17 +0200 Message-ID: <20130408100417.GT20693@game.jcrosoft.org> References: <20130407150938.GA25605@localhost> <1365347572-14972-1-git-send-email-jhovold@gmail.com> <20130408073329.GO20693@game.jcrosoft.org> <20130408084618.GB25605@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20130408084618.GB25605@localhost> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Johan Hovold Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Robert Nelson , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, dgilbert-qazKcTl6WRFWk0Htik3J/w@public.gmane.org List-Id: devicetree@vger.kernel.org On 10:46 Mon 08 Apr , Johan Hovold wrote: > 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. yes must as we used on SAMA5 to pass the boot source from the firstage of the boot loader to the other software