Re: watchdog's pm support preffered implementation

["Janusz Użycki" <j.uzycki@elproma.com.pl>]

Small fix below in the second implementation.

best regards
Janusz

W dniu 2014-09-18 23:40, Janusz Użycki pisze:
> Hi again,
>
> This is the second implementation. Which do you prefer?
>
> Subject: [PATCH] stmp3xxx_rtc_wdt: Add suspend/resume PM support
>
>
> Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
> ---
>  drivers/watchdog/stmp3xxx_rtc_wdt.c | 39 +++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>
> diff --git a/drivers/watchdog/stmp3xxx_rtc_wdt.c 
> b/drivers/watchdog/stmp3xxx_rtc_wdt.c
> index 3546f03..1946277 100644
> --- a/drivers/watchdog/stmp3xxx_rtc_wdt.c
> +++ b/drivers/watchdog/stmp3xxx_rtc_wdt.c
> @@ -95,9 +95,48 @@ static int stmp3xxx_wdt_remove(struct 
> platform_device *pdev)
>         return 0;
>  }
>
> +#ifdef CONFIG_PM_SLEEP
> +/* There is no conflict with rtc/rtc-stmp3xxx.c parent
> + * because modified registers in PM functions are different */
> +static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
> +{
> +       struct watchdog_device *wdd = dev_get_drvdata(dev);

drvdata is NULL, too fast,
+       struct watchdog_device *wdd = &stmp3xxx_wdd;

> +
> +       /* Is keep-on/ping timer suspended before?
> +        * or additional driver-specific flag must be added
> +        *  to block watchdog ping in the timer?
> +        * or disable WATCHDOG_KEEP_ON before wdt_stop
> +        *  and restore it in resume? */
> +       if (watchdog_active(wdd)) {
> +               dev_info(wdd->dev, "%s: wdt was active\n", __func__);
> +               return wdt_stop(wdd);
> +       }
> +       /* should we use pm_runtime like omap_wdt.c does? */
> +
> +       return 0;
> +}
> +
> +static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
> +{
> +       struct watchdog_device *wdd = dev_get_drvdata(dev);
+       struct watchdog_device *wdd = &stmp3xxx_wdd;

> +
> +       if (watchdog_active(wdd)) {
> +               dev_info(wdd->dev, "%s: wdt was active\n", __func__);
> +               return wdt_start(wdd);
> +       }
> +
> +       return 0;
> +}
> +#endif /* CONFIG_PM_SLEEP */
> +
> +static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
> +               stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
> +
>  static struct platform_driver stmp3xxx_wdt_driver = {
>         .driver = {
>                 .name = "stmp3xxx_rtc_wdt",
> +               .owner = THIS_MODULE,
> +               .pm = &stmp3xxx_wdt_pm_ops,
>         },
>         .probe = stmp3xxx_wdt_probe,
>         .remove = stmp3xxx_wdt_remove,
> -- 
> 1.7.11.3
>
>
> W dniu 2014-09-18 13:07, Janusz Użycki pisze:
>>
>> I work under suspend/resume PM support for stmp3xxx driver.
>>
>> Most of them use suspend() with struct platform_device and CONFIG_PM.
>> Only sp805, sirfsoc, s3c2410, dw drivers use suspend() with struct 
>> device
>> and SIMPLE_DEV_PM_OPS.
>> Which implementation is preffered today?
>>
>> best regards
>> Janusz
>>
>> P.S. Patch on the moment:
>> Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
>> ---
>>  drivers/watchdog/stmp3xxx_rtc_wdt.c | 41 +++++++++++++++++++++++
>>  1 file changed, 41 insertions(+)
>>
>> diff --git a/drivers/watchdog/stmp3xxx_rtc_wdt.c 
>> b/drivers/watchdog/stmp3xxx_rtc_wdt.c
>> index 3546f03..12060ab 100644
>> --- a/drivers/watchdog/stmp3xxx_rtc_wdt.c
>> +++ b/drivers/watchdog/stmp3xxx_rtc_wdt.c
>> @@ -74,6 +74,7 @@ static int stmp3xxx_wdt_probe(struct 
>> platform_device *pdev)
>>  {
>>         int ret;
>>
>> +       platform_set_drvdata(pdev, &stmp3xxx_wdd);
>>         watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev);
>>
>>         stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, 
>> STMP3XXX_MAX_TIMEOUT);
>> @@ -95,12 +96,52 @@ static int stmp3xxx_wdt_remove(struct 
>> platform_device *pdev)
>>         return 0;
>>  }
>>
>> +#ifdef CONFIG_PM
>> +/* There is no conflict with rtc/rtc-stmp3xxx.c parent
>> + * because modified registers in PM functions are different */
>> +static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
>> +                                       pm_message_t state)
>> +{
>> +       struct watchdog_device *wdd = platform_get_drvdata(pdev);
>> +
>> +       /* Is keep-on/ping timer suspended before?
>> +        * or additional driver-specific flag must be added
>> +        *  to block watchdog ping in the timer?
>> +        * or disable WATCHDOG_KEEP_ON before wdt_stop
>> +        *  and restore it in resume? */
>> +       if (watchdog_active(wdd)) {
>> +               dev_info(wdd->dev, "%s: wdt was active\n", __func__);
>> +               return wdt_stop(wdd);
>> +       }
>> +       /* should we use pm_runtime like omap_wdt.c does? */
>> +
>> +       return 0;
>> +}
>> +
>> +static int stmp3xxx_wdt_resume(struct platform_device *pdev)
>> +{
>> +       struct watchdog_device *wdd = platform_get_drvdata(pdev);
>> +
>> +       if (watchdog_active(wdd)) {
>> +               dev_info(wdd->dev, "%s: wdt was active\n", __func__);
>> +               return wdt_start(wdd);
>> +       }
>> +
>> +       return 0;
>> +}
>> +#else
>> +#define stmp3xxx_wdt_suspend   NULL
>> +#define stmp3xxx_wdt_resume    NULL
>> +#endif
>> +
>>  static struct platform_driver stmp3xxx_wdt_driver = {
>>         .driver = {
>>                 .name = "stmp3xxx_rtc_wdt",
>>         },
>>         .probe = stmp3xxx_wdt_probe,
>>         .remove = stmp3xxx_wdt_remove,
>> +       .suspend = stmp3xxx_wdt_suspend,
>> +       .resume = stmp3xxx_wdt_resume,
>>  };
>>  module_platform_driver(stmp3xxx_wdt_driver);
>>
>