On 22.01.2024 19:39, Guenter Roeck wrote:
> On 1/22/24 03:11, Claudiu wrote:
>> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
>>
>> The RZ/G3S supports deep sleep states where power to most of the IP blocks
>> is cut off. To ensure proper working of the watchdog when resuming from
>> such states, the suspend function is stopping the watchdog and the resume
>> function is starting it. There is no need to configure the watchdog
>> in case the watchdog was stopped prior to starting suspend.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
>> ---
>> drivers/watchdog/rzg2l_wdt.c | 26 ++++++++++++++++++++++++++
>> 1 file changed, 26 insertions(+)
>>
>> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
>> index 9333dc1a75ab..186796b739f7 100644
>> --- a/drivers/watchdog/rzg2l_wdt.c
>> +++ b/drivers/watchdog/rzg2l_wdt.c
>> @@ -279,6 +279,7 @@ static int rzg2l_wdt_probe(struct platform_device *pdev)
>> priv->wdev.timeout = WDT_DEFAULT_TIMEOUT;
>> watchdog_set_drvdata(&priv->wdev, priv);
>> + dev_set_drvdata(dev, priv);
>> ret = devm_add_action_or_reset(&pdev->dev, rzg2l_wdt_pm_disable,
>> &priv->wdev);
>> if (ret)
>> return ret;
>> @@ -300,10 +301,35 @@ static const struct of_device_id rzg2l_wdt_ids[] = {
>> };
>> MODULE_DEVICE_TABLE(of, rzg2l_wdt_ids);
>> +static int rzg2l_wdt_suspend_late(struct device *dev)
>> +{
>> + struct rzg2l_wdt_priv *priv = dev_get_drvdata(dev);
>> +
>> + if (!watchdog_active(&priv->wdev))
>> + return 0;
>> +
>> + return rzg2l_wdt_stop(&priv->wdev);
>> +}
>> +
>> +static int rzg2l_wdt_resume_early(struct device *dev)
>> +{
>> + struct rzg2l_wdt_priv *priv = dev_get_drvdata(dev);
>> +
>> + if (!watchdog_active(&priv->wdev))
>> + return 0;
>> +
>> + return rzg2l_wdt_start(&priv->wdev);
>> +}
>> +
>> +static const struct dev_pm_ops rzg2l_wdt_pm_ops = {
>> + LATE_SYSTEM_SLEEP_PM_OPS(rzg2l_wdt_suspend_late,
>> rzg2l_wdt_resume_early)
>> +};
>> +
>> static struct platform_driver rzg2l_wdt_driver = {
>> .driver = {
>> .name = "rzg2l_wdt",
>> .of_match_table = rzg2l_wdt_ids,
>> + .pm = pm_ptr(&rzg2l_wdt_pm_ops),
>
> I think this will create a build error if CONFIG_PM=n because rzg2l_wdt_pm_ops
> will be unused but is not marked with __maybe_unused.
The necessity of __maybe_unused has been removed along with the
introduction of LATE_SYSTEM_SLEEP_PM_OPS() and friends (and
*SET_*LATE_SYSTEM_SLEEP_PM_OPS along with the other helpers were marked
deprecated for that) and we can use pm_ptr() along with
LATE_SYSTEM_SLEEP_PM_OPS() to avoid build errors you mentioned.
FYI, I just build the driver with CONFIG_PM=n and all good.
> But then the driver
> won't be
> operational with CONFIG_PM=n, so I really wonder if it makes sense to
> include any
> such conditional code instead of making the driver depend on CONFIG_PM.
That's true. The driver wouldn't work if the CONFIG_PM=n but then it
depends on COMPILE_TEST which is exactly for this (just to compile test it
for platforms that don't support it). I see many watchdog drivers depends
on COMPILE_TEST.
Give this, please let me know would you like me to proceed with it.
Thank you,
Claudiu Beznea
>
> I really don't think it is desirable to suggest that the driver would work
> with
> CONFIG_PM=n if that isn't really true.
>
> Guenter
>
>> },
>> .probe = rzg2l_wdt_probe,
>> };
>
