From: nicolas.ferre@atmel•com (Nicolas Ferre)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] rtc: rtc-at91sam9.c add DT support
Date: Thu, 4 Apr 2013 16:08:04 +0200 [thread overview]
Message-ID: <515D8944.2060308@atmel.com> (raw)
In-Reply-To: <515D7F56.90702@interlog.com>
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
next prev parent reply other threads:[~2013-04-04 14:08 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-04 3:54 [PATCH] rtc: rtc-at91sam9.c add DT support Douglas Gilbert
2013-04-04 8:11 ` Nicolas Ferre
2013-04-04 13:25 ` Douglas Gilbert
2013-04-04 14:08 ` Nicolas Ferre [this message]
2013-04-04 19:14 ` Douglas Gilbert
2013-04-07 15:09 ` Johan Hovold
[not found] ` <1365347572-14972-1-git-send-email-jhovold@gmail.com>
2013-04-08 7:33 ` [RFC 1/5] ARM: at91: add general purpose backup register (GPBR) support Jean-Christophe PLAGNIOL-VILLARD
2013-04-08 8:46 ` Johan Hovold
2013-04-08 10:04 ` Jean-Christophe PLAGNIOL-VILLARD
2013-04-11 12:39 ` Johan Hovold
2013-04-11 14:53 ` Jean-Christophe PLAGNIOL-VILLARD
[not found] ` <1365347572-14972-2-git-send-email-jhovold@gmail.com>
2013-04-08 7:35 ` [RFC 2/5] ARM: at91/dts: " Jean-Christophe PLAGNIOL-VILLARD
[not found] ` <1365347572-14972-4-git-send-email-jhovold@gmail.com>
2013-04-08 7:38 ` [RFC 4/5] RTC: rtc-at91sam9: add device-tree support Jean-Christophe PLAGNIOL-VILLARD
2013-04-08 9:00 ` Johan Hovold
2013-04-08 9:57 ` Nicolas Ferre
2013-04-08 10:03 ` Jean-Christophe PLAGNIOL-VILLARD
2013-04-08 10:42 ` Nicolas Ferre
2013-04-08 11:02 ` Jean-Christophe PLAGNIOL-VILLARD
2013-04-08 10:48 ` Johan Hovold
2013-04-08 11:08 ` Jean-Christophe PLAGNIOL-VILLARD
2013-04-08 10:38 ` Johan Hovold
2013-04-08 11:11 ` Jean-Christophe PLAGNIOL-VILLARD
2013-04-11 12:57 ` Johan Hovold
2013-04-04 8:16 ` [PATCH] rtc: rtc-at91sam9.c add DT support Johan Hovold
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