Patchwork rtc: rtc-twl: ensure IRQ is wakeup enabled

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Submitter Kevin Hilman
Date May 31, 2013, 10:37 p.m.
Message ID <1370039827-25033-1-git-send-email-khilman@linaro.org>
Download mbox | patch
Permalink /patch/248032/
State New
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Comments

Kevin Hilman - May 31, 2013, 10:37 p.m.
Currently, the RTC IRQ is never wakeup-enabled so is not capable of
bringing the system out of suspend.

On OMAP platforms, we have gotten by without this because the TWL RTC
is on an I2C-connected chip which is capable of waking up the OMAP via
the IO ring when the OMAP is in low-power states.

However, if the OMAP suspends without hitting the low-power states
(and the IO ring is not enabled), RTC wakeups will not work because
the IRQ is not wakeup enabled.

To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
set.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
---
 drivers/rtc/rtc-twl.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)
Andrew Morton - June 3, 2013, 11:13 p.m.
On Fri, 31 May 2013 15:37:07 -0700 Kevin Hilman <khilman@linaro.org> wrote:

> Currently, the RTC IRQ is never wakeup-enabled so is not capable of
> bringing the system out of suspend.
> 
> On OMAP platforms, we have gotten by without this because the TWL RTC
> is on an I2C-connected chip which is capable of waking up the OMAP via
> the IO ring when the OMAP is in low-power states.
> 
> However, if the OMAP suspends without hitting the low-power states
> (and the IO ring is not enabled), RTC wakeups will not work because
> the IRQ is not wakeup enabled.
> 
> To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
> set.
> 
> --- a/drivers/rtc/rtc-twl.c
> +++ b/drivers/rtc/rtc-twl.c
> @@ -213,12 +213,24 @@ static int mask_rtc_irq_bit(unsigned char bit)
>  
>  static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
>  {
> +	struct platform_device *pdev = to_platform_device(dev);
> +	int irq = platform_get_irq(pdev, 0);
> +	static bool twl_rtc_wake_enabled;
>  	int ret;
>  
> -	if (enabled)
> +	if (enabled) {
>  		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> -	else
> +		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
> +			enable_irq_wake(irq);
> +			twl_rtc_wake_enabled = true;
> +		}
> +	} else {
>  		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> +		if (twl_rtc_wake_enabled) {
> +			disable_irq_wake(irq);
> +			twl_rtc_wake_enabled = false;
> +		}
> +	}

Why do we need this (slightly racy) logic with twl_rtc_wake_enabled? 
Other drivers don't do this.

Should we test device_may_wakeup() befre running disable_irq_wake()? 
Most drivers seem to do this, but it's all a bit foggy.
Grygorii Strashko - June 4, 2013, 11:32 a.m.
Hi Kevin,

On 06/01/2013 01:37 AM, Kevin Hilman wrote:
> Currently, the RTC IRQ is never wakeup-enabled so is not capable of
> bringing the system out of suspend.
>
> On OMAP platforms, we have gotten by without this because the TWL RTC
> is on an I2C-connected chip which is capable of waking up the OMAP via
> the IO ring when the OMAP is in low-power states.
>
> However, if the OMAP suspends without hitting the low-power states
> (and the IO ring is not enabled), RTC wakeups will not work because
> the IRQ is not wakeup enabled.
As I understand, IRQ wake up capabilities are set/clear simultaneously with
IRQ unmasking/masking on OMAP4+ in omap-wakeupgen.c.
So, it should work without this patch on OMAP4+.
But if TWL is used on non OMAP4+ platform then it is needed.
(OMAP3: I haven't found the place where IRQ wakeup capabilities are 
configured,
would be appreciate if you can point me on)
>
> To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
> set.
>
> Cc: Alessandro Zummo <a.zummo@towertech.it>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Tony Lindgren <tony@atomide.com>
> Signed-off-by: Kevin Hilman <khilman@linaro.org>
> ---
>   drivers/rtc/rtc-twl.c | 16 ++++++++++++++--
>   1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
> index 8751a52..bbda0fd 100644
> --- a/drivers/rtc/rtc-twl.c
> +++ b/drivers/rtc/rtc-twl.c
> @@ -213,12 +213,24 @@ static int mask_rtc_irq_bit(unsigned char bit)
>   
>   static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
>   {
> +	struct platform_device *pdev = to_platform_device(dev);
> +	int irq = platform_get_irq(pdev, 0);
> +	static bool twl_rtc_wake_enabled;
>   	int ret;
>   
> -	if (enabled)
> +	if (enabled) {
>   		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> -	else
> +		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
> +			enable_irq_wake(irq);
> +			twl_rtc_wake_enabled = true;
> +		}
> +	} else {
>   		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> +		if (twl_rtc_wake_enabled) {
> +			disable_irq_wake(irq);
> +			twl_rtc_wake_enabled = false;
> +		}
> +	}
>   
>   	return ret;
>   }
twl-rtc has suspend/resume callbacks implemented, so I think it's the 
better place
for this code and twl_rtc_wake_enabled can be dropped.
Kevin Hilman - June 4, 2013, 5:46 p.m.
Grygorii Strashko <grygorii.strashko@ti.com> writes:

> Hi Kevin,
>
> On 06/01/2013 01:37 AM, Kevin Hilman wrote:
>> Currently, the RTC IRQ is never wakeup-enabled so is not capable of
>> bringing the system out of suspend.
>>
>> On OMAP platforms, we have gotten by without this because the TWL RTC
>> is on an I2C-connected chip which is capable of waking up the OMAP via
>> the IO ring when the OMAP is in low-power states.
>>
>> However, if the OMAP suspends without hitting the low-power states
>> (and the IO ring is not enabled), RTC wakeups will not work because
>> the IRQ is not wakeup enabled.
> As I understand, IRQ wake up capabilities are set/clear simultaneously with
> IRQ unmasking/masking on OMAP4+ in omap-wakeupgen.c.
> So, it should work without this patch on OMAP4+.

It might work on OMAP4 for wakeup from suspend, but without properly
declaring the IRQ as a wakeup source, it will not abort suspend if the
RTC fires during the suspend process.  To abort suspend, the IRQ must be
declared as a wakeup IRQ.

> But if TWL is used on non OMAP4+ platform then it is needed.  (OMAP3:
> I haven't found the place where IRQ wakeup capabilities are
> configured, would be appreciate if you can point me on)

IRQ wakeup is a genirq feature that trickles into the irq_chip (in OMAP3
case, it's the twl4030 irq_chip.)

On OMAP3, as mentioned in the changelog, RTC wake has been working fine
without this because we default to CORE retention, so wakeup happens via
the IO ring.  However, if you prevent retention during suspend, then
this IRQ will not wake the system.

Kevin

>>
>> To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
>> set.
>>
>> Cc: Alessandro Zummo <a.zummo@towertech.it>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Tony Lindgren <tony@atomide.com>
>> Signed-off-by: Kevin Hilman <khilman@linaro.org>
>> ---
>>   drivers/rtc/rtc-twl.c | 16 ++++++++++++++--
>>   1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
>> index 8751a52..bbda0fd 100644
>> --- a/drivers/rtc/rtc-twl.c
>> +++ b/drivers/rtc/rtc-twl.c
>> @@ -213,12 +213,24 @@ static int mask_rtc_irq_bit(unsigned char bit)
>>     static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned
>> enabled)
>>   {
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	int irq = platform_get_irq(pdev, 0);
>> +	static bool twl_rtc_wake_enabled;
>>   	int ret;
>>   -	if (enabled)
>> +	if (enabled) {
>>   		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>> -	else
>> +		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
>> +			enable_irq_wake(irq);
>> +			twl_rtc_wake_enabled = true;
>> +		}
>> +	} else {
>>   		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>> +		if (twl_rtc_wake_enabled) {
>> +			disable_irq_wake(irq);
>> +			twl_rtc_wake_enabled = false;
>> +		}
>> +	}
>>     	return ret;
>>   }
> twl-rtc has suspend/resume callbacks implemented, so I think it's the
> better place
> for this code and twl_rtc_wake_enabled can be dropped.

In theory, that might be the better place (and that's where I put these
at first), but unfortunately, it doesn't work that way because the
twl6030-irq core enables/diables the parent IRQ wake feature using PM
notifiers (which was done to avoid potential lock recursion[1].)

During suspend, the notifier runs at suspend_prepare() time, which is
well before the driver's ->suspend() method is called.  The result is
that the parents IRQ wakeup capabilies are never set.

Kevin


[1]
commit ab2b9260df67e29d5bd69d989f2f84f8c2ed4238
Author: Todd Poynor <toddpoynor@google.com>
Date:   Tue Oct 4 11:52:29 2011 +0200

    mfd: Fix twl6030 lockdep recursion warning on setting wake IRQs
    
    LOCKDEP explicitly sets all irq_desc locks as a single lock-class,
    causing "possible recursive locking detected" when the TWL RTC
    driver calls through enable_irq_wake to twl6030_irq_set_wake,
    which recursively calls irq_set_irq_wake.  Although the
    irq_desc and lock are different, LOCKDEP treats these as
    equivalent, presumably due to problems that can be incurred
    when locking more than one irq_desc, so best to avoid this.
    
    Suspend/resume actions implemented as PM notifiers to avoid
    touch the TWL core for this.
    
    Signed-off-by: Todd Poynor <toddpoynor@google.com>
    Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
    Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Kevin Hilman - June 4, 2013, 5:54 p.m.
Andrew Morton <akpm@linux-foundation.org> writes:

> On Fri, 31 May 2013 15:37:07 -0700 Kevin Hilman <khilman@linaro.org> wrote:
>
>> Currently, the RTC IRQ is never wakeup-enabled so is not capable of
>> bringing the system out of suspend.
>> 
>> On OMAP platforms, we have gotten by without this because the TWL RTC
>> is on an I2C-connected chip which is capable of waking up the OMAP via
>> the IO ring when the OMAP is in low-power states.
>> 
>> However, if the OMAP suspends without hitting the low-power states
>> (and the IO ring is not enabled), RTC wakeups will not work because
>> the IRQ is not wakeup enabled.
>> 
>> To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
>> set.
>> 
>> --- a/drivers/rtc/rtc-twl.c
>> +++ b/drivers/rtc/rtc-twl.c
>> @@ -213,12 +213,24 @@ static int mask_rtc_irq_bit(unsigned char bit)
>>  
>>  static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
>>  {
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	int irq = platform_get_irq(pdev, 0);
>> +	static bool twl_rtc_wake_enabled;
>>  	int ret;
>>  
>> -	if (enabled)
>> +	if (enabled) {
>>  		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>> -	else
>> +		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
>> +			enable_irq_wake(irq);
>> +			twl_rtc_wake_enabled = true;
>> +		}
>> +	} else {
>>  		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>> +		if (twl_rtc_wake_enabled) {
>> +			disable_irq_wake(irq);
>> +			twl_rtc_wake_enabled = false;
>> +		}
>> +	}
>
> Why do we need this (slightly racy) logic with twl_rtc_wake_enabled? 
> Other drivers don't do this.

I suspect the other drivers don't do this because they're making these
calls in their suspend/resume callbacks and can make assumptions about 
the order and balance of the calls (e.g. the PM core will not call your
resume callback if your suspend callback hasn't been called.)  What's
being protected against is imbalanced calling of the IRQ wake calls
(e.g. calling disable_irq_wake() on an IRQ where enable_irq_wake() has
not been called.)

In this patch, I'm using the rtc_alarm_irq_enable() function instead of
the suspend/resume functions because of some limitations of parent
device of this one (I described that at the end of a previous reponse to
this thread[1].)  Because of that, I cannot make the same assumptions
about the ordering of enable/disable calls to this function.

> Should we test device_may_wakeup() befre running disable_irq_wake()? 
> Most drivers seem to do this, but it's all a bit foggy.

I suppose I could've added that check too for symmetry, but it would be
redundant because the twl_rtc_wake_enabled flag can only be set when
device_can_wakeup() == true.

Kevin

[1] http://marc.info/?l=linux-omap&m=137036801320665&w=2
Grygorii Strashko - June 5, 2013, 2:32 p.m.
On 06/04/2013 08:46 PM, Kevin Hilman wrote:
> Grygorii Strashko <grygorii.strashko@ti.com> writes:
>
>> Hi Kevin,
>>
>> On 06/01/2013 01:37 AM, Kevin Hilman wrote:
>>> Currently, the RTC IRQ is never wakeup-enabled so is not capable of
>>> bringing the system out of suspend.
>>>
>>> On OMAP platforms, we have gotten by without this because the TWL RTC
>>> is on an I2C-connected chip which is capable of waking up the OMAP via
>>> the IO ring when the OMAP is in low-power states.
>>>
>>> However, if the OMAP suspends without hitting the low-power states
>>> (and the IO ring is not enabled), RTC wakeups will not work because
>>> the IRQ is not wakeup enabled.
>> As I understand, IRQ wake up capabilities are set/clear simultaneously with
>> IRQ unmasking/masking on OMAP4+ in omap-wakeupgen.c.
>> So, it should work without this patch on OMAP4+.
> It might work on OMAP4 for wakeup from suspend, but without properly
> declaring the IRQ as a wakeup source, it will not abort suspend if the
> RTC fires during the suspend process.  To abort suspend, the IRQ must be
> declared as a wakeup IRQ.
>
>> But if TWL is used on non OMAP4+ platform then it is needed.  (OMAP3:
>> I haven't found the place where IRQ wakeup capabilities are
>> configured, would be appreciate if you can point me on)
> IRQ wakeup is a genirq feature that trickles into the irq_chip (in OMAP3
> case, it's the twl4030 irq_chip.)
>
> On OMAP3, as mentioned in the changelog, RTC wake has been working fine
> without this because we default to CORE retention, so wakeup happens via
> the IO ring.  However, if you prevent retention during suspend, then
> this IRQ will not wake the system.
>
> Kevin
>
>>> To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
>>> set.
>>>
>>> Cc: Alessandro Zummo <a.zummo@towertech.it>
>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>> Cc: Tony Lindgren <tony@atomide.com>
>>> Signed-off-by: Kevin Hilman <khilman@linaro.org>
>>> ---
>>>    drivers/rtc/rtc-twl.c | 16 ++++++++++++++--
>>>    1 file changed, 14 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
>>> index 8751a52..bbda0fd 100644
>>> --- a/drivers/rtc/rtc-twl.c
>>> +++ b/drivers/rtc/rtc-twl.c
>>> @@ -213,12 +213,24 @@ static int mask_rtc_irq_bit(unsigned char bit)
>>>      static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned
>>> enabled)
>>>    {
>>> +	struct platform_device *pdev = to_platform_device(dev);
>>> +	int irq = platform_get_irq(pdev, 0);
>>> +	static bool twl_rtc_wake_enabled;
>>>    	int ret;
>>>    -	if (enabled)
>>> +	if (enabled) {
>>>    		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>>> -	else
>>> +		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
>>> +			enable_irq_wake(irq);
>>> +			twl_rtc_wake_enabled = true;
>>> +		}
>>> +	} else {
>>>    		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>>> +		if (twl_rtc_wake_enabled) {
>>> +			disable_irq_wake(irq);
>>> +			twl_rtc_wake_enabled = false;
>>> +		}
>>> +	}
>>>      	return ret;
>>>    }
>> twl-rtc has suspend/resume callbacks implemented, so I think it's the
>> better place
>> for this code and twl_rtc_wake_enabled can be dropped.
> In theory, that might be the better place (and that's where I put these
> at first), but unfortunately, it doesn't work that way because the
> twl6030-irq core enables/diables the parent IRQ wake feature using PM
> notifiers (which was done to avoid potential lock recursion[1].)
>
> During suspend, the notifier runs at suspend_prepare() time, which is
> well before the driver's ->suspend() method is called.  The result is
> that the parents IRQ wakeup capabilies are never set.
Sorry, forget about this patch - have no questions for this patch anymore.

Thanks.

Just FYI. It seems, The suspend will never be aborted on OMAP4 by SYSN_IRQ
because of these two patches:
782baa2 mfd: Disable twl6030 IRQ during suspend
9c6079a genirq: Do not consider disabled wakeup irqs

-grygorii
>
> Kevin
>
>
> [1]
> commit ab2b9260df67e29d5bd69d989f2f84f8c2ed4238
> Author: Todd Poynor <toddpoynor@google.com>
> Date:   Tue Oct 4 11:52:29 2011 +0200
>
>      mfd: Fix twl6030 lockdep recursion warning on setting wake IRQs
>      
>      LOCKDEP explicitly sets all irq_desc locks as a single lock-class,
>      causing "possible recursive locking detected" when the TWL RTC
>      driver calls through enable_irq_wake to twl6030_irq_set_wake,
>      which recursively calls irq_set_irq_wake.  Although the
>      irq_desc and lock are different, LOCKDEP treats these as
>      equivalent, presumably due to problems that can be incurred
>      when locking more than one irq_desc, so best to avoid this.
>      
>      Suspend/resume actions implemented as PM notifiers to avoid
>      touch the TWL core for this.
>      
>      Signed-off-by: Todd Poynor <toddpoynor@google.com>
>      Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
>      Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Kevin Hilman - June 5, 2013, 3:32 p.m.
Grygorii Strashko <grygorii.strashko@ti.com> writes:

> On 06/04/2013 08:46 PM, Kevin Hilman wrote:
>> Grygorii Strashko <grygorii.strashko@ti.com> writes:
>>
>>> Hi Kevin,
>>>
>>> On 06/01/2013 01:37 AM, Kevin Hilman wrote:
>>>> Currently, the RTC IRQ is never wakeup-enabled so is not capable of
>>>> bringing the system out of suspend.
>>>>
>>>> On OMAP platforms, we have gotten by without this because the TWL RTC
>>>> is on an I2C-connected chip which is capable of waking up the OMAP via
>>>> the IO ring when the OMAP is in low-power states.
>>>>
>>>> However, if the OMAP suspends without hitting the low-power states
>>>> (and the IO ring is not enabled), RTC wakeups will not work because
>>>> the IRQ is not wakeup enabled.
>>> As I understand, IRQ wake up capabilities are set/clear simultaneously with
>>> IRQ unmasking/masking on OMAP4+ in omap-wakeupgen.c.
>>> So, it should work without this patch on OMAP4+.
>> It might work on OMAP4 for wakeup from suspend, but without properly
>> declaring the IRQ as a wakeup source, it will not abort suspend if the
>> RTC fires during the suspend process.  To abort suspend, the IRQ must be
>> declared as a wakeup IRQ.
>>
>>> But if TWL is used on non OMAP4+ platform then it is needed.  (OMAP3:
>>> I haven't found the place where IRQ wakeup capabilities are
>>> configured, would be appreciate if you can point me on)
>> IRQ wakeup is a genirq feature that trickles into the irq_chip (in OMAP3
>> case, it's the twl4030 irq_chip.)
>>
>> On OMAP3, as mentioned in the changelog, RTC wake has been working fine
>> without this because we default to CORE retention, so wakeup happens via
>> the IO ring.  However, if you prevent retention during suspend, then
>> this IRQ will not wake the system.
>>
>> Kevin
>>
>>>> To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
>>>> set.
>>>>
>>>> Cc: Alessandro Zummo <a.zummo@towertech.it>
>>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>>> Cc: Tony Lindgren <tony@atomide.com>
>>>> Signed-off-by: Kevin Hilman <khilman@linaro.org>
>>>> ---
>>>>    drivers/rtc/rtc-twl.c | 16 ++++++++++++++--
>>>>    1 file changed, 14 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
>>>> index 8751a52..bbda0fd 100644
>>>> --- a/drivers/rtc/rtc-twl.c
>>>> +++ b/drivers/rtc/rtc-twl.c
>>>> @@ -213,12 +213,24 @@ static int mask_rtc_irq_bit(unsigned char bit)
>>>>      static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned
>>>> enabled)
>>>>    {
>>>> +	struct platform_device *pdev = to_platform_device(dev);
>>>> +	int irq = platform_get_irq(pdev, 0);
>>>> +	static bool twl_rtc_wake_enabled;
>>>>    	int ret;
>>>>    -	if (enabled)
>>>> +	if (enabled) {
>>>>    		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>>>> -	else
>>>> +		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
>>>> +			enable_irq_wake(irq);
>>>> +			twl_rtc_wake_enabled = true;
>>>> +		}
>>>> +	} else {
>>>>    		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
>>>> +		if (twl_rtc_wake_enabled) {
>>>> +			disable_irq_wake(irq);
>>>> +			twl_rtc_wake_enabled = false;
>>>> +		}
>>>> +	}
>>>>      	return ret;
>>>>    }
>>> twl-rtc has suspend/resume callbacks implemented, so I think it's the
>>> better place
>>> for this code and twl_rtc_wake_enabled can be dropped.
>> In theory, that might be the better place (and that's where I put these
>> at first), but unfortunately, it doesn't work that way because the
>> twl6030-irq core enables/diables the parent IRQ wake feature using PM
>> notifiers (which was done to avoid potential lock recursion[1].)
>>
>> During suspend, the notifier runs at suspend_prepare() time, which is
>> well before the driver's ->suspend() method is called.  The result is
>> that the parents IRQ wakeup capabilies are never set.
> Sorry, forget about this patch - have no questions for this patch anymore.
>
> Thanks.
>
> Just FYI. It seems, The suspend will never be aborted on OMAP4 by SYSN_IRQ
> because of these two patches:
> 782baa2 mfd: Disable twl6030 IRQ during suspend
> 9c6079a genirq: Do not consider disabled wakeup irqs

You're right for the parent TWL IRQ, but the child interrupts (e.g. RTC)
would still abort suspend if wakeup enabled.

Kevin

Patch

diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
index 8751a52..bbda0fd 100644
--- a/drivers/rtc/rtc-twl.c
+++ b/drivers/rtc/rtc-twl.c
@@ -213,12 +213,24 @@  static int mask_rtc_irq_bit(unsigned char bit)
 
 static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
 {
+	struct platform_device *pdev = to_platform_device(dev);
+	int irq = platform_get_irq(pdev, 0);
+	static bool twl_rtc_wake_enabled;
 	int ret;
 
-	if (enabled)
+	if (enabled) {
 		ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
-	else
+		if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
+			enable_irq_wake(irq);
+			twl_rtc_wake_enabled = true;
+		}
+	} else {
 		ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
+		if (twl_rtc_wake_enabled) {
+			disable_irq_wake(irq);
+			twl_rtc_wake_enabled = false;
+		}
+	}
 
 	return ret;
 }