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

From: Guenter Roeck
Date: Sat Apr 25 2020 - 13:50:08 EST


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@xxxxxxxxx>
> Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

> ---
> 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)