linux-kernel - Re: [PATCH 1/4] rtc: sa1100: enable/disable rtc when probe/remove the device

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Date:	Tue, 4 Dec 2012 10:51:50 +0800
From:	Chao Xie <xiechao.mail@...il.com>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
Cc:	Haojian Zhuang <haojian.zhuang@...il.com>,
	Chao Xie <chao.xie@...vell.com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	rtc-linux@...glegroups.com,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 1/4] rtc: sa1100: enable/disable rtc when probe/remove the device

On Mon, Dec 3, 2012 at 5:48 PM, Russell King - ARM Linux
<linux@....linux.org.uk> wrote:
> On Mon, Dec 03, 2012 at 10:53:07AM +0800, Chao Xie wrote:
>> I want to correct what i said. For the irq register/unregister i think
>> can be done at open/release. But for clock enable/disable, i do not
>> think so. If clock is disabled, as i think RTC will not work. User API
>> still use open->get_time->close for "date" command. It means that RTC
>> will not return correct date to user.
>
> "I think" is not good enough for patches like this.  Please test it.
>
> On SA11x0 and PXA platforms, the clock for the sa1100-rtc is a dummy
> clock; it has no effect.  For MMP, I don't have access to the TRMs so
> that's something you're going to have to find out.

I tested at pxa910 which uses rtc-sa1100 as driver.
the test procedure is simple
open->ioctl(RTC_RD_TIME)->close
With the original code, the rtc will not update, i always get the same value

remove clock disable/enable in release/open, and enable/disable clock
at probe/remove.
the rtc can update, and i can read the correct rtc value.
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