rtc: ds1374: wdt:support suspend/resume for watchdog

When enable CONFIG_RTC_DRV_DS1374_WDT use as watchdog,
in suspend mode, watchdog is still working but no daemon
patting the watchdog. The system will reboot if timeout.
So disable watchdog in suspend  and recover it in resume.

Signed-off-by: winton.liu <18502523564@163.com>
---
 drivers/rtc/rtc-ds1374.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(+Cc wdt maintainers)

On 26/09/2017 at 09:56:32 +0800, 18502523564 wrote:
> Hi Alexandre,
> 
> Thanks for your reply.
> Do you think is this a issue when using as a watchdog in suspend?
> I takes the drivers/watchdog/ subsystem for reference, some drivers in suspend
> also call disable_watchdog.Or do you have any  better suggestion?

I guess this is a question for the watchdog subsystem maintainers.
However, I think that everything can be handled properly from userspace
as I know some atmel based devices have their watchdog enabled while
the platform is suspended.

> Thank you.
> 
> 
> 
> 
> ------------------ Original ------------------
> From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> Date: 周一,9月 25,2017 20:07
> To: winton.liu <18502523564@163.com>
> Cc: a.zummo <a.zummo@towertech.it>, linux-rtc <linux-rtc@vger.kernel.org>,
> linux-kernel <linux-kernel@vger.kernel.org>
> Subject: Re: [PATCH] rtc: ds1374: wdt:support suspend/resume for watchdog
> 
> 
> Hi,
> 
> On 25/09/2017 at 19:58:44 +0800, winton.liu wrote:
> > When enable CONFIG_RTC_DRV_DS1374_WDT use as watchdog,
> > in suspend mode, watchdog is still working but no daemon
> > patting the watchdog. The system will reboot if timeout.
> > So disable watchdog in suspend  and recover it in resume.
> >
> 
> That is definitively not what we want. Many people will want to still
> have the watchdog running when the platform is suspended. Your options
> are to either disable the watchdog before going to suspend or wake up
> the platform just in time to ping the watchdog.
> 
> > Signed-off-by: winton.liu <18502523564@163.com>
> > ---
> >  drivers/rtc/rtc-ds1374.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c
> > index 38a2e9e..e990773 100644
> > --- a/drivers/rtc/rtc-ds1374.c
> > +++ b/drivers/rtc/rtc-ds1374.c
> > @@ -690,6 +690,10 @@ static int ds1374_suspend(struct device *dev)
> >  {
> >       struct i2c_client *client = to_i2c_client(dev);
> >
> > +#ifdef CONFIG_RTC_DRV_DS1374_WDT
> > +     ds1374_wdt_disable();
> > +#endif
> > +
> >       if (client->irq > 0 && device_may_wakeup(&client->dev))
> >               enable_irq_wake(client->irq);
> >       return 0;
> > @@ -699,6 +703,10 @@ static int ds1374_resume(struct device *dev)
> >  {
> >       struct i2c_client *client = to_i2c_client(dev);
> >
> > +#ifdef CONFIG_RTC_DRV_DS1374_WDT
> > +     ds1374_wdt_settimeout(131072);
> > +#endif
> > +
> >       if (client->irq > 0 && device_may_wakeup(&client->dev))
> >               disable_irq_wake(client->irq);
> >       return 0;
> > --
> > 1.9.1
> >
> >
> 
> --
> Alexandre Belloni, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com
>

On 09/26/2017 03:22 AM, Alexandre Belloni wrote:
> (+Cc wdt maintainers)
> 
> On 26/09/2017 at 09:56:32 +0800, 18502523564 wrote:
>> Hi Alexandre,
>>
>> Thanks for your reply.
>> Do you think is this a issue when using as a watchdog in suspend?
>> I takes the drivers/watchdog/ subsystem for reference, some drivers in suspend
>> also call disable_watchdog.Or do you have any  better suggestion?
> 
> I guess this is a question for the watchdog subsystem maintainers.
> However, I think that everything can be handled properly from userspace
> as I know some atmel based devices have their watchdog enabled while
> the platform is suspended.
> 

Depends on the driver, really. There is one thing wrong below, though:
It appears that on resume, the watchdog is unconditionally enabled.

Guenter

>> Thank you.
>>
>>
>>
>>
>> ------------------ Original ------------------
>> From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
>> Date: 周一,9月 25,2017 20:07
>> To: winton.liu <18502523564@163.com>
>> Cc: a.zummo <a.zummo@towertech.it>, linux-rtc <linux-rtc@vger.kernel.org>,
>> linux-kernel <linux-kernel@vger.kernel.org>
>> Subject: Re: [PATCH] rtc: ds1374: wdt:support suspend/resume for watchdog
>>
>>
>> Hi,
>>
>> On 25/09/2017 at 19:58:44 +0800, winton.liu wrote:
>>> When enable CONFIG_RTC_DRV_DS1374_WDT use as watchdog,
>>> in suspend mode, watchdog is still working but no daemon
>>> patting the watchdog. The system will reboot if timeout.
>>> So disable watchdog in suspend  and recover it in resume.
>>>
>>
>> That is definitively not what we want. Many people will want to still
>> have the watchdog running when the platform is suspended. Your options
>> are to either disable the watchdog before going to suspend or wake up
>> the platform just in time to ping the watchdog.
>>
>>> Signed-off-by: winton.liu <18502523564@163.com>
>>> ---
>>>   drivers/rtc/rtc-ds1374.c | 8 ++++++++
>>>   1 file changed, 8 insertions(+)
>>>
>>> diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c
>>> index 38a2e9e..e990773 100644
>>> --- a/drivers/rtc/rtc-ds1374.c
>>> +++ b/drivers/rtc/rtc-ds1374.c
>>> @@ -690,6 +690,10 @@ static int ds1374_suspend(struct device *dev)
>>>   {
>>>        struct i2c_client *client = to_i2c_client(dev);
>>>
>>> +#ifdef CONFIG_RTC_DRV_DS1374_WDT
>>> +     ds1374_wdt_disable();
>>> +#endif
>>> +
>>>        if (client->irq > 0 && device_may_wakeup(&client->dev))
>>>                enable_irq_wake(client->irq);
>>>        return 0;
>>> @@ -699,6 +703,10 @@ static int ds1374_resume(struct device *dev)
>>>   {
>>>        struct i2c_client *client = to_i2c_client(dev);
>>>
>>> +#ifdef CONFIG_RTC_DRV_DS1374_WDT
>>> +     ds1374_wdt_settimeout(131072);
>>> +#endif
>>> +
>>>        if (client->irq > 0 && device_may_wakeup(&client->dev))
>>>                disable_irq_wake(client->irq);
>>>        return 0;
>>> --
>>> 1.9.1
>>>
>>>
>>
>> --
>> Alexandre Belloni, Free Electrons
>> Embedded Linux and Kernel engineering
>> http://free-electrons.com
>>
>

Hi Guenter & Alexander,

Sorry for late update. I have modified the resume function.
    resume: disable existing watchdog, reload watchdog timer, enable watchdog
Could you help to review attached patch ?
Thanks a lot.

Winton.Liu









At 2017-09-26 21:52:24, "Guenter Roeck" <linux@roeck-us.net> wrote:
>On 09/26/2017 03:22 AM, Alexandre Belloni wrote:
>> (+Cc wdt maintainers)
>> 
>> On 26/09/2017 at 09:56:32 +0800, 18502523564 wrote:
>>> Hi Alexandre,
>>>
>>> Thanks for your reply.
>>> Do you think is this a issue when using as a watchdog in suspend?
>>> I takes the drivers/watchdog/ subsystem for reference, some drivers in suspend
>>> also call disable_watchdog.Or do you have any  better suggestion?
>> 
>> I guess this is a question for the watchdog subsystem maintainers.
>> However, I think that everything can be handled properly from userspace
>> as I know some atmel based devices have their watchdog enabled while
>> the platform is suspended.
>> 
>
>Depends on the driver, really. There is one thing wrong below, though:
>It appears that on resume, the watchdog is unconditionally enabled.
>
>Guenter
>
>>> Thank you.
>>>
>>>
>>>
>>>
>>> ------------------ Original ------------------
>>> From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
>>> Date: 周一,9月 25,2017 20:07
>>> To: winton.liu <18502523564@163.com>
>>> Cc: a.zummo <a.zummo@towertech.it>, linux-rtc <linux-rtc@vger.kernel.org>,
>>> linux-kernel <linux-kernel@vger.kernel.org>
>>> Subject: Re: [PATCH] rtc: ds1374: wdt:support suspend/resume for watchdog
>>>
>>>
>>> Hi,
>>>
>>> On 25/09/2017 at 19:58:44 +0800, winton.liu wrote:
>>>> When enable CONFIG_RTC_DRV_DS1374_WDT use as watchdog,
>>>> in suspend mode, watchdog is still working but no daemon
>>>> patting the watchdog. The system will reboot if timeout.
>>>> So disable watchdog in suspend  and recover it in resume.
>>>>
>>>
>>> That is definitively not what we want. Many people will want to still
>>> have the watchdog running when the platform is suspended. Your options
>>> are to either disable the watchdog before going to suspend or wake up
>>> the platform just in time to ping the watchdog.
>>>
>>>> Signed-off-by: winton.liu <18502523564@163.com>
>>>> ---
>>>>   drivers/rtc/rtc-ds1374.c | 8 ++++++++
>>>>   1 file changed, 8 insertions(+)
>>>>
>>>> diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c
>>>> index 38a2e9e..e990773 100644
>>>> --- a/drivers/rtc/rtc-ds1374.c
>>>> +++ b/drivers/rtc/rtc-ds1374.c
>>>> @@ -690,6 +690,10 @@ static int ds1374_suspend(struct device *dev)
>>>>   {
>>>>        struct i2c_client *client = to_i2c_client(dev);
>>>>
>>>> +#ifdef CONFIG_RTC_DRV_DS1374_WDT
>>>> +     ds1374_wdt_disable();
>>>> +#endif
>>>> +
>>>>        if (client->irq > 0 && device_may_wakeup(&client->dev))
>>>>                enable_irq_wake(client->irq);
>>>>        return 0;
>>>> @@ -699,6 +703,10 @@ static int ds1374_resume(struct device *dev)
>>>>   {
>>>>        struct i2c_client *client = to_i2c_client(dev);
>>>>
>>>> +#ifdef CONFIG_RTC_DRV_DS1374_WDT
>>>> +     ds1374_wdt_settimeout(131072);
>>>> +#endif
>>>> +
>>>>        if (client->irq > 0 && device_may_wakeup(&client->dev))
>>>>                disable_irq_wake(client->irq);
>>>>        return 0;
>>>> --
>>>> 1.9.1
>>>>
>>>>
>>>
>>> --
>>> Alexandre Belloni, Free Electrons
>>> Embedded Linux and Kernel engineering
>>> http://free-electrons.com
>>>
>> 
>