rtc: sun6i: Allow RTC wakeup after shutdown

Only IRQs that have enable_irq_wake() called on them can wake the system
from sleep or after it has been shut down. Currently, the RTC alarm can
only wake the system from sleep. Run the suspend callback to arm the IRQ
during the shutdown process, so the RTC alarm also works after shutdown.

Signed-off-by: Samuel Holland <samuel@sholland.org>

drivers/rtc/rtc-sun6i.c

@@ -679,7 +679,6 @@ static const struct rtc_class_ops sun6i_rtc_ops = {
 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
 };
 
-#ifdef CONFIG_PM_SLEEP
 /* Enable IRQ wake on suspend, to wake up from RTC. */
 static int sun6i_rtc_suspend(struct device *dev)
 {
@@ -692,7 +691,7 @@ static int sun6i_rtc_suspend(struct device *dev)
 }
 
 /* Disable IRQ wake on resume. */
-static int sun6i_rtc_resume(struct device *dev)
+static int __maybe_unused sun6i_rtc_resume(struct device *dev)
 {
 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
 
@@ -701,7 +700,6 @@ static int sun6i_rtc_resume(struct device *dev)
 
 	return 0;
 }
-#endif
 
 static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
 	sun6i_rtc_suspend, sun6i_rtc_resume);
@@ -817,6 +815,11 @@ static int sun6i_rtc_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static void sun6i_rtc_shutdown(struct platform_device *pdev)
+{
+	sun6i_rtc_suspend(&pdev->dev);
+}
+
 /*
  * As far as RTC functionality goes, all models are the same. The
  * datasheets claim that different models have different number of
@@ -839,6 +842,7 @@ MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
 
 static struct platform_driver sun6i_rtc_driver = {
 	.probe		= sun6i_rtc_probe,
+	.shutdown	= sun6i_rtc_shutdown,
 	.driver		= {
 		.name		= "sun6i-rtc",
 		.of_match_table = sun6i_rtc_dt_ids,