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

From: Haojian Zhuang
Date: Tue Dec 04 2012 - 02:01:40 EST

On Tuesday, December 4, 2012, Chao Xie wrote:
> On Mon, Dec 3, 2012 at 5:48 PM, Russell King - ARM Linux
> <linux@xxxxxxxxxxxxxxxx> 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.

Yes, clock shouldn't be controlled in open/close. Otherwise, RTC can't
work since
clock is already gated. I didn't find the issue since there're two RTC
enabled in my
board. The default one impacts the test.

I think that you need send the patch that only move clock operation
into probe().
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