[RFC PATCH v5 4/4] PM: domains: Add and set generic sync state callback

[Abel Vesa <abel.vesa@linaro.org>]

For every provider that doesn't register a sync_state callback,
register a generic one. This new generic sync_state callback queues up a
power off request.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
---
 drivers/base/power/domain.c | 23 +++++++++++++++++++++++
 include/linux/pm_domain.h   |  3 +++
 2 files changed, 26 insertions(+)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 5967ade160e2..ec16db0599ac 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -654,6 +654,27 @@ static void genpd_queue_power_off_work(struct generic_pm_domain *genpd)
 	queue_work(pm_wq, &genpd->power_off_work);
 }
 
+/**
+ * pm_genpd_power_off_unused_sync_state - Power off all domains for provider.
+ * @dev: Provider's device.
+ *
+ * Request power off for all unused domains of the provider.
+ * This should be used exclusively as sync state callback for genpd providers.
+ */
+void pm_genpd_power_off_unused_sync_state(struct device *dev)
+{
+	struct generic_pm_domain *genpd;
+
+	mutex_lock(&gpd_list_lock);
+
+	list_for_each_entry(genpd, &gpd_list, gpd_list_node)
+		if (genpd->provider && genpd->provider->dev == dev)
+			genpd_queue_power_off_work(genpd);
+
+	mutex_unlock(&gpd_list_lock);
+}
+EXPORT_SYMBOL_GPL(pm_genpd_power_off_unused_sync_state);
+
 /**
  * genpd_keep_on - Tells if the domain should skip the power 'off' request
  * @genpd: PM domain to be checked.
@@ -2329,6 +2350,8 @@ static int genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
 	cp->xlate = xlate;
 	fwnode_dev_initialized(&np->fwnode, true);
 
+	dev_set_drv_sync_state(np->fwnode.dev, pm_genpd_power_off_unused_sync_state);
+
 	mutex_lock(&of_genpd_mutex);
 	list_add(&cp->link, &of_genpd_providers);
 	mutex_unlock(&of_genpd_mutex);
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 3eb32c4b6d4f..78164244b89f 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -279,6 +279,9 @@ static inline int pm_genpd_remove(struct generic_pm_domain *genpd)
 	return -EOPNOTSUPP;
 }
 
+static inline void pm_genpd_power_off_unused_sync_state(struct device *dev)
+{ }
+
 static inline int dev_pm_genpd_set_performance_state(struct device *dev,
 						     unsigned int state)
 {
-- 
2.34.1