Re: watchdog's pm support preffered implementation

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

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);
+
+       /* 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);
+
+       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);
>