pmdomain: core: Default to use of_genpd_sync_state() for genpd providers

Unless the typical platform driver that act as genpd provider, has its own
->sync_state() callback implemented let's default to use
of_genpd_sync_state().

More precisely, while adding a genpd OF provider let's assign the
->sync_state() callback, in case the fwnode has a device and its driver
doesn't have the ->sync_state() set already. In this way the typical
platform driver doesn't need to assign ->sync_state(), unless it has some
additional things to manage beyond genpds.

Suggested-by: Saravana Kannan <saravanak@google.com>
Tested-by: Hiago De Franco <hiago.franco@toradex.com> # Colibri iMX8X
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> # TI AM62A,Xilinx ZynqMP ZCU106
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20250701114733.636510-21-ulf.hansson@linaro.org

drivers/pmdomain/core.c

@@ -2600,6 +2600,11 @@ static bool genpd_present(const struct generic_pm_domain *genpd)
 	return ret;
 }
 
+static void genpd_sync_state(struct device *dev)
+{
+	return of_genpd_sync_state(dev->of_node);
+}
+
 /**
  * of_genpd_add_provider_simple() - Register a simple PM domain provider
  * @np: Device node pointer associated with the PM domain provider.
@@ -2628,6 +2633,8 @@ int of_genpd_add_provider_simple(struct device_node *np,
 	if (!dev && !genpd_is_no_sync_state(genpd)) {
 		genpd->sync_state = GENPD_SYNC_STATE_SIMPLE;
 		device_set_node(&genpd->dev, fwnode);
+	} else {
+		dev_set_drv_sync_state(dev, genpd_sync_state);
 	}
 
 	put_device(dev);
@@ -2700,6 +2707,8 @@ int of_genpd_add_provider_onecell(struct device_node *np,
 	dev = get_dev_from_fwnode(fwnode);
 	if (!dev)
 		sync_state = true;
+	else
+		dev_set_drv_sync_state(dev, genpd_sync_state);
 
 	put_device(dev);