[PATCH v2 04/21] pmdomain: core: Export a common ->sync_state() helper for genpd providers

[Ulf Hansson]

In some cases the typical platform driver that act as genpd provider, may
need its own ->sync_state() callback to manage various things. In this
regards, the provider most likely wants to allow its corresponding genpds
to be powered-off.

For this reason, let's introduce a new genpd helper function,
of_genpd_sync_state() that helps genpd provider drivers to achieve this.

Suggested-by: Saravana Kannan <saravanak at google.com>
Reviewed-by: Abel Vesa <abel.vesa at linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
---

Changes in v2:
	- Changed the in-parameter from a struct device* to a stuct device_node*

---
 drivers/pmdomain/core.c   | 27 +++++++++++++++++++++++++++
 include/linux/pm_domain.h |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 8d5dca22e35e..4047af5a275d 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -3408,6 +3408,33 @@ int of_genpd_parse_idle_states(struct device_node *dn,
 }
 EXPORT_SYMBOL_GPL(of_genpd_parse_idle_states);
 
+/**
+ * of_genpd_sync_state() - A common sync_state function for genpd providers
+ * @np: The device node the genpd provider is associated with.
+ *
+ * The @np that corresponds to a genpd provider may provide one or multiple
+ * genpds. This function makes use @np to find the genpds that belongs to the
+ * provider. For each genpd we try a power-off.
+ */
+void of_genpd_sync_state(struct device_node *np)
+{
+	struct generic_pm_domain *genpd;
+
+	if (!np)
+		return;
+
+	mutex_lock(&gpd_list_lock);
+	list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
+		if (genpd->provider == of_fwnode_handle(np)) {
+			genpd_lock(genpd);
+			genpd_power_off(genpd, false, 0);
+			genpd_unlock(genpd);
+		}
+	}
+	mutex_unlock(&gpd_list_lock);
+}
+EXPORT_SYMBOL_GPL(of_genpd_sync_state);
+
 static int genpd_provider_probe(struct device *dev)
 {
 	return 0;
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 0b18160901a2..3578196e6626 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -431,6 +431,7 @@ int of_genpd_remove_subdomain(const struct of_phandle_args *parent_spec,
 struct generic_pm_domain *of_genpd_remove_last(struct device_node *np);
 int of_genpd_parse_idle_states(struct device_node *dn,
 			       struct genpd_power_state **states, int *n);
+void of_genpd_sync_state(struct device_node *np);
 
 int genpd_dev_pm_attach(struct device *dev);
 struct device *genpd_dev_pm_attach_by_id(struct device *dev,
@@ -476,6 +477,8 @@ static inline int of_genpd_parse_idle_states(struct device_node *dn,
 	return -ENODEV;
 }
 
+static inline void of_genpd_sync_state(struct device_node *np) {}
+
 static inline int genpd_dev_pm_attach(struct device *dev)
 {
 	return 0;
-- 
2.43.0