linux-kernel - Re: [PATCH] watchdog: apple: Deactivate on suspend

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Message-ID: <e0a6f9f3-b472-4fda-829c-5d8f29234a4f@roeck-us.net>
Date:   Sat, 30 Sep 2023 04:58:15 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     j@...nau.net
Cc:     Hector Martin <marcan@...can.st>, Sven Peter <sven@...npeter.dev>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        asahi@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
        linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] watchdog: apple: Deactivate on suspend

On Sat, Sep 30, 2023 at 10:19:26AM +0200, Janne Grunau via B4 Relay wrote:
> From: Janne Grunau <j@...nau.net>
> 
> The watchdog remains active after putting the system into suspend. Add
> PM callbacks to deactivate the watchdog on suspend an re-activate it on
> resume.
> 
> Signed-off-by: Janne Grunau <j@...nau.net>
> ---
>  drivers/watchdog/apple_wdt.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c
> index eddeb0fede89..2167e0ba705e 100644
> --- a/drivers/watchdog/apple_wdt.c
> +++ b/drivers/watchdog/apple_wdt.c
> @@ -173,6 +173,8 @@ static int apple_wdt_probe(struct platform_device *pdev)
>  	if (!wdt->clk_rate)
>  		return -EINVAL;
>  
> +	platform_set_drvdata(pdev, wdt);
> +
>  	wdt->wdd.ops = &apple_wdt_ops;
>  	wdt->wdd.info = &apple_wdt_info;
>  	wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate;
> @@ -190,6 +192,28 @@ static int apple_wdt_probe(struct platform_device *pdev)
>  	return devm_watchdog_register_device(dev, &wdt->wdd);
>  }
>  
> +static int __maybe_unused apple_wdt_resume(struct device *dev)
> +{
> +	struct apple_wdt *wdt = dev_get_drvdata(dev);
> +
> +	if (watchdog_active(&wdt->wdd) || watchdog_hw_running(&wdt->wdd))
> +		apple_wdt_start(&wdt->wdd);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused apple_wdt_suspend(struct device *dev)
> +{
> +	struct apple_wdt *wdt = dev_get_drvdata(dev);
> +
> +	if (watchdog_active(&wdt->wdd) || watchdog_hw_running(&wdt->wdd))
> +		apple_wdt_stop(&wdt->wdd);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(apple_wdt_pm_ops, apple_wdt_suspend, apple_wdt_resume);

Comments above that define say

/* Deprecated. Use DEFINE_SIMPLE_DEV_PM_OPS() instead. */

and with that the __maybe_unused is no longer necessary.

> +
>  static const struct of_device_id apple_wdt_of_match[] = {
>  	{ .compatible = "apple,wdt" },
>  	{},
> @@ -200,6 +224,7 @@ static struct platform_driver apple_wdt_driver = {
>  	.driver = {
>  		.name = "apple-watchdog",
>  		.of_match_table = apple_wdt_of_match,
> +		.pm = pm_sleep_ptr(&apple_wdt_pm_ops),
>  	},
>  	.probe = apple_wdt_probe,
>  };
> 
> ---
> base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d
> change-id: 20230930-apple-watchdog-suspend-7f73831130fb
> 
> Best regards,
> -- 
> Janne Grunau <j@...nau.net>
>