diff mbox

Revert "drivers/rtc/rtc-at91rm9200.c: use a variable for storing IMR"

Message ID 1364982862-19759-1-git-send-email-jhovold@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Johan Hovold April 3, 2013, 9:54 a.m. UTC
This reverts commit 0ef1594c017521ea89278e80fe3f80dafb17abde.

This patch introduced a few races which cannot be easily fixed with a
small follow-up patch. Furthermore, the SoC with the broken hardware
register, which this patch intended to add support for, can only be used
with device trees, which this driver currently does not support.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
---
 drivers/rtc/rtc-at91rm9200.c | 50 +++++++++++++++++---------------------------
 drivers/rtc/rtc-at91rm9200.h |  1 +
 2 files changed, 20 insertions(+), 31 deletions(-)

Comments

Nicolas Ferre April 3, 2013, 10:18 a.m. UTC | #1
On 04/03/2013 11:54 AM, Johan Hovold :
> This reverts commit 0ef1594c017521ea89278e80fe3f80dafb17abde.
> 
> This patch introduced a few races which cannot be easily fixed with a
> small follow-up patch. Furthermore, the SoC with the broken hardware
> register, which this patch intended to add support for, can only be used
> with device trees, which this driver currently does not support.
> 
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Johan Hovold <jhovold@gmail.com>

Fair enough, after fighting to find a solution that can makes us move
forward... your strong arguments convinced me.

So, Andrew, please can you take this "revert" patch for 3.9-rc ?
And sorry for the noise.

Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>

(Andrew, I figured out that you are not in copy of the original email:
do I need to send it back to you or can you pick it up in patchwork?
https://patchwork.kernel.org/patch/2385921/
)

> ---
>  drivers/rtc/rtc-at91rm9200.c | 50 +++++++++++++++++---------------------------
>  drivers/rtc/rtc-at91rm9200.h |  1 +
>  2 files changed, 20 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
> index 0a9f27e..434ebc3 100644
> --- a/drivers/rtc/rtc-at91rm9200.c
> +++ b/drivers/rtc/rtc-at91rm9200.c
> @@ -44,7 +44,6 @@ static DECLARE_COMPLETION(at91_rtc_updated);
>  static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
>  static void __iomem *at91_rtc_regs;
>  static int irq;
> -static u32 at91_rtc_imr;
>  
>  /*
>   * Decode time/date into rtc_time structure
> @@ -109,11 +108,9 @@ static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
>  	cr = at91_rtc_read(AT91_RTC_CR);
>  	at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
>  
> -	at91_rtc_imr |= AT91_RTC_ACKUPD;
>  	at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
>  	wait_for_completion(&at91_rtc_updated);	/* wait for ACKUPD interrupt */
>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
> -	at91_rtc_imr &= ~AT91_RTC_ACKUPD;
>  
>  	at91_rtc_write(AT91_RTC_TIMR,
>  			  bin2bcd(tm->tm_sec) << 0
> @@ -145,7 +142,7 @@ static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
>  	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
>  	tm->tm_year = at91_alarm_year - 1900;
>  
> -	alrm->enabled = (at91_rtc_imr & AT91_RTC_ALARM)
> +	alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
>  			? 1 : 0;
>  
>  	dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
> @@ -171,7 +168,6 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
>  	tm.tm_sec = alrm->time.tm_sec;
>  
>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
> -	at91_rtc_imr &= ~AT91_RTC_ALARM;
>  	at91_rtc_write(AT91_RTC_TIMALR,
>  		  bin2bcd(tm.tm_sec) << 0
>  		| bin2bcd(tm.tm_min) << 8
> @@ -184,7 +180,6 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
>  
>  	if (alrm->enabled) {
>  		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
> -		at91_rtc_imr |= AT91_RTC_ALARM;
>  		at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
>  	}
>  
> @@ -201,12 +196,9 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
>  
>  	if (enabled) {
>  		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
> -		at91_rtc_imr |= AT91_RTC_ALARM;
>  		at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
> -	} else {
> +	} else
>  		at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
> -		at91_rtc_imr &= ~AT91_RTC_ALARM;
> -	}
>  
>  	return 0;
>  }
> @@ -215,10 +207,12 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
>   */
>  static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
>  {
> +	unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
> +
>  	seq_printf(seq, "update_IRQ\t: %s\n",
> -			(at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no");
> +			(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
>  	seq_printf(seq, "periodic_IRQ\t: %s\n",
> -			(at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no");
> +			(imr & AT91_RTC_SECEV) ? "yes" : "no");
>  
>  	return 0;
>  }
> @@ -233,7 +227,7 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
>  	unsigned int rtsr;
>  	unsigned long events = 0;
>  
> -	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_imr;
> +	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
>  	if (rtsr) {		/* this interrupt is shared!  Is it ours? */
>  		if (rtsr & AT91_RTC_ALARM)
>  			events |= (RTC_AF | RTC_IRQF);
> @@ -297,7 +291,6 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
>  					AT91_RTC_SECEV | AT91_RTC_TIMEV |
>  					AT91_RTC_CALEV);
> -	at91_rtc_imr = 0;
>  
>  	ret = request_irq(irq, at91_rtc_interrupt,
>  				IRQF_SHARED,
> @@ -336,7 +329,6 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
>  					AT91_RTC_SECEV | AT91_RTC_TIMEV |
>  					AT91_RTC_CALEV);
> -	at91_rtc_imr = 0;
>  	free_irq(irq, pdev);
>  
>  	rtc_device_unregister(rtc);
> @@ -349,35 +341,31 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
>  
>  /* AT91RM9200 RTC Power management control */
>  
> -static u32 at91_rtc_bkpimr;
> -
> +static u32 at91_rtc_imr;
>  
>  static int at91_rtc_suspend(struct device *dev)
>  {
>  	/* this IRQ is shared with DBGU and other hardware which isn't
>  	 * necessarily doing PM like we are...
>  	 */
> -	at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV);
> -	if (at91_rtc_bkpimr) {
> -		if (device_may_wakeup(dev)) {
> +	at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
> +			& (AT91_RTC_ALARM|AT91_RTC_SECEV);
> +	if (at91_rtc_imr) {
> +		if (device_may_wakeup(dev))
>  			enable_irq_wake(irq);
> -		} else {
> -			at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr);
> -			at91_rtc_imr &= ~at91_rtc_bkpimr;
> -		}
> -}
> +		else
> +			at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
> +	}
>  	return 0;
>  }
>  
>  static int at91_rtc_resume(struct device *dev)
>  {
> -	if (at91_rtc_bkpimr) {
> -		if (device_may_wakeup(dev)) {
> +	if (at91_rtc_imr) {
> +		if (device_may_wakeup(dev))
>  			disable_irq_wake(irq);
> -		} else {
> -			at91_rtc_imr |= at91_rtc_bkpimr;
> -			at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr);
> -		}
> +		else
> +			at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
>  	}
>  	return 0;
>  }
> diff --git a/drivers/rtc/rtc-at91rm9200.h b/drivers/rtc/rtc-at91rm9200.h
> index 5f940b6..da1945e 100644
> --- a/drivers/rtc/rtc-at91rm9200.h
> +++ b/drivers/rtc/rtc-at91rm9200.h
> @@ -64,6 +64,7 @@
>  #define	AT91_RTC_SCCR		0x1c			/* Status Clear Command Register */
>  #define	AT91_RTC_IER		0x20			/* Interrupt Enable Register */
>  #define	AT91_RTC_IDR		0x24			/* Interrupt Disable Register */
> +#define	AT91_RTC_IMR		0x28			/* Interrupt Mask Register */
>  
>  #define	AT91_RTC_VER		0x2c			/* Valid Entry Register */
>  #define		AT91_RTC_NVTIM		(1 <<  0)		/* Non valid Time */
>
Nicolas Ferre April 5, 2013, 2:14 p.m. UTC | #2
On 04/03/2013 12:18 PM, Nicolas Ferre :
> On 04/03/2013 11:54 AM, Johan Hovold :
>> This reverts commit 0ef1594c017521ea89278e80fe3f80dafb17abde.
>>
>> This patch introduced a few races which cannot be easily fixed with a
>> small follow-up patch. Furthermore, the SoC with the broken hardware
>> register, which this patch intended to add support for, can only be used
>> with device trees, which this driver currently does not support.
>>
>> Cc: stable <stable@vger.kernel.org>
>> Signed-off-by: Johan Hovold <jhovold@gmail.com>
> 
> Fair enough, after fighting to find a solution that can makes us move
> forward... your strong arguments convinced me.
> 
> So, Andrew, please can you take this "revert" patch for 3.9-rc ?
> And sorry for the noise.
> 
> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> 
> (Andrew, I figured out that you are not in copy of the original email:
> do I need to send it back to you or can you pick it up in patchwork?
> https://patchwork.kernel.org/patch/2385921/
> )

Andrew, ping?

Thanks, best regards,

>> ---
>>  drivers/rtc/rtc-at91rm9200.c | 50 +++++++++++++++++---------------------------
>>  drivers/rtc/rtc-at91rm9200.h |  1 +
>>  2 files changed, 20 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
>> index 0a9f27e..434ebc3 100644
>> --- a/drivers/rtc/rtc-at91rm9200.c
>> +++ b/drivers/rtc/rtc-at91rm9200.c
>> @@ -44,7 +44,6 @@ static DECLARE_COMPLETION(at91_rtc_updated);
>>  static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
>>  static void __iomem *at91_rtc_regs;
>>  static int irq;
>> -static u32 at91_rtc_imr;
>>  
>>  /*
>>   * Decode time/date into rtc_time structure
>> @@ -109,11 +108,9 @@ static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
>>  	cr = at91_rtc_read(AT91_RTC_CR);
>>  	at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
>>  
>> -	at91_rtc_imr |= AT91_RTC_ACKUPD;
>>  	at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
>>  	wait_for_completion(&at91_rtc_updated);	/* wait for ACKUPD interrupt */
>>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
>> -	at91_rtc_imr &= ~AT91_RTC_ACKUPD;
>>  
>>  	at91_rtc_write(AT91_RTC_TIMR,
>>  			  bin2bcd(tm->tm_sec) << 0
>> @@ -145,7 +142,7 @@ static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
>>  	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
>>  	tm->tm_year = at91_alarm_year - 1900;
>>  
>> -	alrm->enabled = (at91_rtc_imr & AT91_RTC_ALARM)
>> +	alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
>>  			? 1 : 0;
>>  
>>  	dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
>> @@ -171,7 +168,6 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
>>  	tm.tm_sec = alrm->time.tm_sec;
>>  
>>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
>> -	at91_rtc_imr &= ~AT91_RTC_ALARM;
>>  	at91_rtc_write(AT91_RTC_TIMALR,
>>  		  bin2bcd(tm.tm_sec) << 0
>>  		| bin2bcd(tm.tm_min) << 8
>> @@ -184,7 +180,6 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
>>  
>>  	if (alrm->enabled) {
>>  		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
>> -		at91_rtc_imr |= AT91_RTC_ALARM;
>>  		at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
>>  	}
>>  
>> @@ -201,12 +196,9 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
>>  
>>  	if (enabled) {
>>  		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
>> -		at91_rtc_imr |= AT91_RTC_ALARM;
>>  		at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
>> -	} else {
>> +	} else
>>  		at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
>> -		at91_rtc_imr &= ~AT91_RTC_ALARM;
>> -	}
>>  
>>  	return 0;
>>  }
>> @@ -215,10 +207,12 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
>>   */
>>  static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
>>  {
>> +	unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
>> +
>>  	seq_printf(seq, "update_IRQ\t: %s\n",
>> -			(at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no");
>> +			(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
>>  	seq_printf(seq, "periodic_IRQ\t: %s\n",
>> -			(at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no");
>> +			(imr & AT91_RTC_SECEV) ? "yes" : "no");
>>  
>>  	return 0;
>>  }
>> @@ -233,7 +227,7 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
>>  	unsigned int rtsr;
>>  	unsigned long events = 0;
>>  
>> -	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_imr;
>> +	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
>>  	if (rtsr) {		/* this interrupt is shared!  Is it ours? */
>>  		if (rtsr & AT91_RTC_ALARM)
>>  			events |= (RTC_AF | RTC_IRQF);
>> @@ -297,7 +291,6 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
>>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
>>  					AT91_RTC_SECEV | AT91_RTC_TIMEV |
>>  					AT91_RTC_CALEV);
>> -	at91_rtc_imr = 0;
>>  
>>  	ret = request_irq(irq, at91_rtc_interrupt,
>>  				IRQF_SHARED,
>> @@ -336,7 +329,6 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
>>  	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
>>  					AT91_RTC_SECEV | AT91_RTC_TIMEV |
>>  					AT91_RTC_CALEV);
>> -	at91_rtc_imr = 0;
>>  	free_irq(irq, pdev);
>>  
>>  	rtc_device_unregister(rtc);
>> @@ -349,35 +341,31 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
>>  
>>  /* AT91RM9200 RTC Power management control */
>>  
>> -static u32 at91_rtc_bkpimr;
>> -
>> +static u32 at91_rtc_imr;
>>  
>>  static int at91_rtc_suspend(struct device *dev)
>>  {
>>  	/* this IRQ is shared with DBGU and other hardware which isn't
>>  	 * necessarily doing PM like we are...
>>  	 */
>> -	at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV);
>> -	if (at91_rtc_bkpimr) {
>> -		if (device_may_wakeup(dev)) {
>> +	at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
>> +			& (AT91_RTC_ALARM|AT91_RTC_SECEV);
>> +	if (at91_rtc_imr) {
>> +		if (device_may_wakeup(dev))
>>  			enable_irq_wake(irq);
>> -		} else {
>> -			at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr);
>> -			at91_rtc_imr &= ~at91_rtc_bkpimr;
>> -		}
>> -}
>> +		else
>> +			at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
>> +	}
>>  	return 0;
>>  }
>>  
>>  static int at91_rtc_resume(struct device *dev)
>>  {
>> -	if (at91_rtc_bkpimr) {
>> -		if (device_may_wakeup(dev)) {
>> +	if (at91_rtc_imr) {
>> +		if (device_may_wakeup(dev))
>>  			disable_irq_wake(irq);
>> -		} else {
>> -			at91_rtc_imr |= at91_rtc_bkpimr;
>> -			at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr);
>> -		}
>> +		else
>> +			at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
>>  	}
>>  	return 0;
>>  }
>> diff --git a/drivers/rtc/rtc-at91rm9200.h b/drivers/rtc/rtc-at91rm9200.h
>> index 5f940b6..da1945e 100644
>> --- a/drivers/rtc/rtc-at91rm9200.h
>> +++ b/drivers/rtc/rtc-at91rm9200.h
>> @@ -64,6 +64,7 @@
>>  #define	AT91_RTC_SCCR		0x1c			/* Status Clear Command Register */
>>  #define	AT91_RTC_IER		0x20			/* Interrupt Enable Register */
>>  #define	AT91_RTC_IDR		0x24			/* Interrupt Disable Register */
>> +#define	AT91_RTC_IMR		0x28			/* Interrupt Mask Register */
>>  
>>  #define	AT91_RTC_VER		0x2c			/* Valid Entry Register */
>>  #define		AT91_RTC_NVTIM		(1 <<  0)		/* Non valid Time */
>>
> 
>
Greg KH April 5, 2013, 3:35 p.m. UTC | #3
On Fri, Apr 05, 2013 at 04:14:35PM +0200, Nicolas Ferre wrote:
> On 04/03/2013 12:18 PM, Nicolas Ferre :
> > On 04/03/2013 11:54 AM, Johan Hovold :
> >> This reverts commit 0ef1594c017521ea89278e80fe3f80dafb17abde.
> >>
> >> This patch introduced a few races which cannot be easily fixed with a
> >> small follow-up patch. Furthermore, the SoC with the broken hardware
> >> register, which this patch intended to add support for, can only be used
> >> with device trees, which this driver currently does not support.
> >>
> >> Cc: stable <stable@vger.kernel.org>
> >> Signed-off-by: Johan Hovold <jhovold@gmail.com>
> > 
> > Fair enough, after fighting to find a solution that can makes us move
> > forward... your strong arguments convinced me.
> > 
> > So, Andrew, please can you take this "revert" patch for 3.9-rc ?
> > And sorry for the noise.
> > 
> > Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> > 
> > (Andrew, I figured out that you are not in copy of the original email:
> > do I need to send it back to you or can you pick it up in patchwork?
> > https://patchwork.kernel.org/patch/2385921/
> > )
> 
> Andrew, ping?

Andrew is on vacation for a few weeks, sorry.

Perhaps you should send this yourself?

greg k-h
diff mbox

Patch

diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index 0a9f27e..434ebc3 100644
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -44,7 +44,6 @@  static DECLARE_COMPLETION(at91_rtc_updated);
 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
 static void __iomem *at91_rtc_regs;
 static int irq;
-static u32 at91_rtc_imr;
 
 /*
  * Decode time/date into rtc_time structure
@@ -109,11 +108,9 @@  static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 	cr = at91_rtc_read(AT91_RTC_CR);
 	at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 
-	at91_rtc_imr |= AT91_RTC_ACKUPD;
 	at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
 	wait_for_completion(&at91_rtc_updated);	/* wait for ACKUPD interrupt */
 	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
-	at91_rtc_imr &= ~AT91_RTC_ACKUPD;
 
 	at91_rtc_write(AT91_RTC_TIMR,
 			  bin2bcd(tm->tm_sec) << 0
@@ -145,7 +142,7 @@  static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 	tm->tm_year = at91_alarm_year - 1900;
 
-	alrm->enabled = (at91_rtc_imr & AT91_RTC_ALARM)
+	alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
 			? 1 : 0;
 
 	dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
@@ -171,7 +168,6 @@  static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	tm.tm_sec = alrm->time.tm_sec;
 
 	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
-	at91_rtc_imr &= ~AT91_RTC_ALARM;
 	at91_rtc_write(AT91_RTC_TIMALR,
 		  bin2bcd(tm.tm_sec) << 0
 		| bin2bcd(tm.tm_min) << 8
@@ -184,7 +180,6 @@  static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 
 	if (alrm->enabled) {
 		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
-		at91_rtc_imr |= AT91_RTC_ALARM;
 		at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
 	}
 
@@ -201,12 +196,9 @@  static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 
 	if (enabled) {
 		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
-		at91_rtc_imr |= AT91_RTC_ALARM;
 		at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
-	} else {
+	} else
 		at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
-		at91_rtc_imr &= ~AT91_RTC_ALARM;
-	}
 
 	return 0;
 }
@@ -215,10 +207,12 @@  static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  */
 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 {
+	unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
+
 	seq_printf(seq, "update_IRQ\t: %s\n",
-			(at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no");
+			(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 	seq_printf(seq, "periodic_IRQ\t: %s\n",
-			(at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no");
+			(imr & AT91_RTC_SECEV) ? "yes" : "no");
 
 	return 0;
 }
@@ -233,7 +227,7 @@  static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 	unsigned int rtsr;
 	unsigned long events = 0;
 
-	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_imr;
+	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
 	if (rtsr) {		/* this interrupt is shared!  Is it ours? */
 		if (rtsr & AT91_RTC_ALARM)
 			events |= (RTC_AF | RTC_IRQF);
@@ -297,7 +291,6 @@  static int __init at91_rtc_probe(struct platform_device *pdev)
 	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 					AT91_RTC_SECEV | AT91_RTC_TIMEV |
 					AT91_RTC_CALEV);
-	at91_rtc_imr = 0;
 
 	ret = request_irq(irq, at91_rtc_interrupt,
 				IRQF_SHARED,
@@ -336,7 +329,6 @@  static int __exit at91_rtc_remove(struct platform_device *pdev)
 	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 					AT91_RTC_SECEV | AT91_RTC_TIMEV |
 					AT91_RTC_CALEV);
-	at91_rtc_imr = 0;
 	free_irq(irq, pdev);
 
 	rtc_device_unregister(rtc);
@@ -349,35 +341,31 @@  static int __exit at91_rtc_remove(struct platform_device *pdev)
 
 /* AT91RM9200 RTC Power management control */
 
-static u32 at91_rtc_bkpimr;
-
+static u32 at91_rtc_imr;
 
 static int at91_rtc_suspend(struct device *dev)
 {
 	/* this IRQ is shared with DBGU and other hardware which isn't
 	 * necessarily doing PM like we are...
 	 */
-	at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV);
-	if (at91_rtc_bkpimr) {
-		if (device_may_wakeup(dev)) {
+	at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
+			& (AT91_RTC_ALARM|AT91_RTC_SECEV);
+	if (at91_rtc_imr) {
+		if (device_may_wakeup(dev))
 			enable_irq_wake(irq);
-		} else {
-			at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr);
-			at91_rtc_imr &= ~at91_rtc_bkpimr;
-		}
-}
+		else
+			at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
+	}
 	return 0;
 }
 
 static int at91_rtc_resume(struct device *dev)
 {
-	if (at91_rtc_bkpimr) {
-		if (device_may_wakeup(dev)) {
+	if (at91_rtc_imr) {
+		if (device_may_wakeup(dev))
 			disable_irq_wake(irq);
-		} else {
-			at91_rtc_imr |= at91_rtc_bkpimr;
-			at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr);
-		}
+		else
+			at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
 	}
 	return 0;
 }
diff --git a/drivers/rtc/rtc-at91rm9200.h b/drivers/rtc/rtc-at91rm9200.h
index 5f940b6..da1945e 100644
--- a/drivers/rtc/rtc-at91rm9200.h
+++ b/drivers/rtc/rtc-at91rm9200.h
@@ -64,6 +64,7 @@ 
 #define	AT91_RTC_SCCR		0x1c			/* Status Clear Command Register */
 #define	AT91_RTC_IER		0x20			/* Interrupt Enable Register */
 #define	AT91_RTC_IDR		0x24			/* Interrupt Disable Register */
+#define	AT91_RTC_IMR		0x28			/* Interrupt Mask Register */
 
 #define	AT91_RTC_VER		0x2c			/* Valid Entry Register */
 #define		AT91_RTC_NVTIM		(1 <<  0)		/* Non valid Time */