From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Ferre Subject: Re: [PATCH] rtc: rtc-at91sam9.c add DT support Date: Thu, 4 Apr 2013 16:08:04 +0200 Message-ID: <515D8944.2060308@atmel.com> References: <515CF985.6050009@interlog.com> <515D35C2.7050405@atmel.com> <515D7F56.90702@interlog.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <515D7F56.90702-qazKcTl6WRFWk0Htik3J/w@public.gmane.org> 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: dgilbert-qazKcTl6WRFWk0Htik3J/w@public.gmane.org, Johan Hovold Cc: devicetree-discuss , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Robert Nelson List-Id: devicetree@vger.kernel.org On 04/04/2013 03:25 PM, Douglas Gilbert : > On 13-04-04 04:11 AM, Nicolas Ferre wrote: >> On 04/04/2013 05:54 AM, Douglas Gilbert : >>> Some members of the at91 SoCs use the Real Time Timer (RTT) >>> and the General Purpose Backup Registers (GPBR) to implement >>> a real time clock (RTC). The AT91SAM9G20 is one example. >>> >>> Attached is a patch to add DT support to rtc-at91sam9.c . >>> The patch is against lk 3.9.0-rc5 . >>> >>> Below is a snippet of DT code for the 'G20 that was observed >>> to work with this patch: >>> >>> ahb { >>> apb { >>> >>> rtc { >>> compatible = "atmel,at91sam9-rtc"; >> >> The compatible string has to be formed by the name of the first SoC >> compatible with this IP. It turns to be the at91sam9260. >> The second part of the string should be a name that reflects the nature >> of the peripheral. For this binding, I would like to mention the "RTT" >> in the compatibility string (because other drivers can use other RTT >> with other uses). >> >> What do you think about: >> "atmel,at91sam9260-rtt-as-rtc"? or something shorter? > > Hi Nicolas, > Johan Hovold suggested: > atmel,at91sam9260-rtt Yes, but I fear this could bring confusion if someone is building a RTT driver that is not targeted at acting as a RTC... > I notice (in the G20 doco) that the acronym RTTC is also used The "C" at the end stands for "Controller" (not very useful convention in my opinion). > for the rtt registers. What do you want? I found xxx-rtt-as-rtc or xxx-rtt-rtc but not completely satisfied with any of them... >>> /* RTTC followed by GPBR (backup registers) */ >>> reg = <0xfffffd20 0x10>, <0xfffffd50 0x10>; >>> interrupts = <1 4 7>; >>> status = "okay"; >> >> Last, but not least, when we add a DT binding, it is a requirement to >> add the corresponding documentation in the >> Documentation/devicetree/bindings/rtc/ directory. > > I have been underwhelmed by the accuracy and the organisation > of information in that documentation. And the examples are > often misleading given the actual hierarchy of real dtsi/dts > config files. Oh, really? I will have a look one of those days... > Give me working examples any day. You could (and should) test > what I gave on a g20ek board. > > Also I note there is no "bindings" documentation for > rtc-at91rm9200.c :-) After you, sir .... Already submitted, my dear ;-) Here: http://ozlabs.org/~akpm/mmots/broken-out/drivers-rtc-rtc-at91rm9200c-add-dt-support.patch Bye, -- Nicolas Ferre