linux-kernel - Re: [PATCH 3/3] watchdog: da9062: add power management ops

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Message-ID: <20200123205132.GA13377@roeck-us.net>
Date:   Thu, 23 Jan 2020 12:51:32 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Marco Felsch <m.felsch@...gutronix.de>
Cc:     support.opensource@...semi.com, robh+dt@...nel.org,
        lee.jones@...aro.org, stwiss.opensource@...semi.com,
        Adam.Thomson.Opensource@...semi.com,
        linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel@...gutronix.de
Subject: Re: [PATCH 3/3] watchdog: da9062: add power management ops

On Wed, Jan 08, 2020 at 10:57:04AM +0100, Marco Felsch wrote:
> Disable the watchdog during suspend if it is enabled and re-enable it on
> resume. So we can sleep without the interruptions.
> 
> Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
> Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@...semi.com>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
> v2:
> - add dlg,use-sw-pm check to differentiate between automatic and manual
>   disabling/enabling.
> ---
>  drivers/watchdog/da9062_wdt.c | 37 +++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
> index e149e66a6ea9..c9b9d6394525 100644
> --- a/drivers/watchdog/da9062_wdt.c
> +++ b/drivers/watchdog/da9062_wdt.c
> @@ -15,6 +15,7 @@
>  #include <linux/jiffies.h>
>  #include <linux/mfd/da9062/registers.h>
>  #include <linux/mfd/da9062/core.h>
> +#include <linux/property.h>
>  #include <linux/regmap.h>
>  #include <linux/of.h>
>  
> @@ -30,6 +31,7 @@ static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
>  struct da9062_watchdog {
>  	struct da9062 *hw;
>  	struct watchdog_device wdtdev;
> +	bool use_sw_pm;
>  };
>  
>  static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
> @@ -198,6 +200,8 @@ static int da9062_wdt_probe(struct platform_device *pdev)
>  	if (!wdt)
>  		return -ENOMEM;
>  
> +	wdt->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
> +
>  	wdt->hw = chip;
>  
>  	wdt->wdtdev.info = &da9062_watchdog_info;
> @@ -212,6 +216,7 @@ static int da9062_wdt_probe(struct platform_device *pdev)
>  	watchdog_set_restart_priority(&wdt->wdtdev, 128);
>  
>  	watchdog_set_drvdata(&wdt->wdtdev, wdt);
> +	dev_set_drvdata(dev, &wdt->wdtdev);
>  
>  	ret = devm_watchdog_register_device(dev, &wdt->wdtdev);
>  	if (ret < 0)
> @@ -220,10 +225,42 @@ static int da9062_wdt_probe(struct platform_device *pdev)
>  	return da9062_wdt_ping(&wdt->wdtdev);
>  }
>  
> +static int __maybe_unused da9062_wdt_suspend(struct device *dev)
> +{
> +	struct watchdog_device *wdd = dev_get_drvdata(dev);
> +	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
> +
> +	if (!wdt->use_sw_pm)
> +		return 0;
> +
> +	if (watchdog_active(wdd))
> +		return da9062_wdt_stop(wdd);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused da9062_wdt_resume(struct device *dev)
> +{
> +	struct watchdog_device *wdd = dev_get_drvdata(dev);
> +	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
> +
> +	if (!wdt->use_sw_pm)
> +		return 0;
> +
> +	if (watchdog_active(wdd))
> +		return da9062_wdt_start(wdd);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(da9062_wdt_pm_ops,
> +			 da9062_wdt_suspend, da9062_wdt_resume);
> +
>  static struct platform_driver da9062_wdt_driver = {
>  	.probe = da9062_wdt_probe,
>  	.driver = {
>  		.name = "da9062-watchdog",
> +		.pm = &da9062_wdt_pm_ops,
>  		.of_match_table = da9062_compatible_id_table,
>  	},
>  };