linux-kernel - Re: [patch 2.6.20-rc3 1/3] rtc-cmos driver

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Date:	Mon, 28 May 2007 19:35:14 +0100
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	David Brownell <david-b@...bell.net>
Cc:	Alessandro Zummo <alessandro.zummo@...ertech.it>,
	rtc-linux@...glegroups.com,
	Linux Kernel list <linux-kernel@...r.kernel.org>
Subject: Re: [patch 2.6.20-rc3 1/3] rtc-cmos driver

On Fri, Jan 05, 2007 at 10:01:57AM -0800, David Brownell wrote:
> This is an "RTC framework" driver for the "CMOS" RTCs which are standard
> on PCs and some other platforms.  That's MC146818 compatible silicon.
> Advantages of this vs. drivers/char/rtc.c (use one _or_ the other, only
> one will be able to claim the RTC irq) include:

Sorry for getting to this so late - I've only just started playing with 
this driver.

> +static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)

This is awkward. At the very least, year will be set to -1. This then 
gets passed through to rtc_tm_to_time, which results in reading 
wakealarm providing very odd feedback. I guess the "right" fix is for 
rtc_tm_to_time to use the current values for anything that's -1?

> +	rtc_control = CMOS_READ(RTC_CONTROL);
> +	rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);

Do you really want to clobber RTC_AIE on probe? If an alarm has been set 
by the BIOS, it seems a little unfair to disable it on boot.

-- 
Matthew Garrett | mjg59@...f.ucam.org
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