Re: [PATCH v2 1/3] watchdog: da9062: Initialize timeout during probe

[Guenter Roeck <linux@roeck-us.net>]

On Fri, Apr 03, 2020 at 03:07:26PM +0200, Stefan Riedmueller wrote:
> During probe try to set the timeout from device tree and fall back to
> either the pre-configured timeout set by e.g. the bootloader in case the
> watchdog is already running or the default value.
> 
> If the watchdog is already running make sure to update the timeout and
> tell the framework about the running state to make sure the watchdog is
> handled correctly until user space takes over. Updating the timeout also
> removes the need for an additional manual ping so we can remove that as
> well.
> 
> Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
> Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>

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

> ---
> Changes in v2:
>  - Reworked the patch to use the pre-configured timeout instead of the default
>    value as a fallback in case no DT value is present.
>  - To achieve the previous point watchdog_init_timeout was added to get the
>    DT value if present.
>  - Added a timeout update if the watchdog is running to set the desired
>    timeout and in this instance removed the manual ping at the end.
>  - Removed info message.
> ---
>  drivers/watchdog/da9062_wdt.c | 27 ++++++++++++++++++++++-----
>  1 file changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
> index 0ad15d55071c..10b37dd65bed 100644
> --- a/drivers/watchdog/da9062_wdt.c
> +++ b/drivers/watchdog/da9062_wdt.c
> @@ -35,6 +35,15 @@ struct da9062_watchdog {
>  	bool use_sw_pm;
>  };
>  
> +static unsigned int da9062_wdt_read_timeout(struct da9062_watchdog *wdt)
> +{
> +	unsigned int val;
> +
> +	regmap_read(wdt->hw->regmap, DA9062AA_CONTROL_D, &val);
> +
> +	return wdt_timeout[val & DA9062AA_TWDSCALE_MASK];
> +}
> +
>  static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
>  {
>  	unsigned int i;
> @@ -183,7 +192,7 @@ MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
>  static int da9062_wdt_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> -	int ret;
> +	unsigned int timeout;
>  	struct da9062 *chip;
>  	struct da9062_watchdog *wdt;
>  
> @@ -213,11 +222,19 @@ static int da9062_wdt_probe(struct platform_device *pdev)
>  	watchdog_set_drvdata(&wdt->wdtdev, wdt);
>  	dev_set_drvdata(dev, &wdt->wdtdev);
>  
> -	ret = devm_watchdog_register_device(dev, &wdt->wdtdev);
> -	if (ret < 0)
> -		return ret;
> +	timeout = da9062_wdt_read_timeout(wdt);
> +	if (timeout)
> +		wdt->wdtdev.timeout = timeout;
> +
> +	/* Set timeout from DT value if available */
> +	watchdog_init_timeout(&wdt->wdtdev, 0, dev);
> +
> +	if (timeout) {
> +		da9062_wdt_set_timeout(&wdt->wdtdev, wdt->wdtdev.timeout);
> +		set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
> +	}
>  
> -	return da9062_wdt_ping(&wdt->wdtdev);
> +	return devm_watchdog_register_device(dev, &wdt->wdtdev);
>  }
>  
>  static int __maybe_unused da9062_wdt_suspend(struct device *dev)