[PATCH 2/3] pmdomain: core: add support for subdomains via power-domain-map

[Kevin Hilman]

---
 drivers/pmdomain/core.c   | 60 +++++++++++++++++++++++++++++++++++++++
 include/linux/pm_domain.h | 11 +++++++
 2 files changed, 71 insertions(+)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 88819659df83..a0dc60d4160d 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -3100,6 +3100,66 @@ struct device *genpd_dev_pm_attach_by_name(struct device *dev, const char *name)
 	return genpd_dev_pm_attach_by_id(dev, index);
 }
 
+/**
+ * genpd_dev_pm_attach_subdomain - Associate a PM domain with its parent domain
+ * @domain: The PM domain to lookup whether it has any parent
+ * @dev: The device being attached to the PM domain.
+ *
+ * Check if @domain has a power-domain-map.  If present, use that map
+ * to determine the parent PM domain, and attach @domain as a
+ * subdomain to the parent PM domain.
+ *
+ * Intended to called from a PM domain provider's ->attach_dev()
+ * callback, where &gpd_list_lock will already be held by the genpd
+ * add_device() path.
+ */
+struct generic_pm_domain *
+genpd_dev_pm_attach_subdomain(struct generic_pm_domain *domain,
+			      struct device *dev)
+{
+	struct of_phandle_args parent_args;
+	struct generic_pm_domain *parent_pd = NULL;
+	int ret;
+
+	/*
+	 * Check for power-domain-map, which implies the primary
+	 * power-doamin is a subdomain of the parent found in the map.
+	 */
+	ret = of_parse_phandle_with_args_map(dev->of_node, "power-domains",
+					     "power-domain", 0, &parent_args);
+	if (!ret && parent_args.np) {
+		parent_pd = genpd_get_from_provider(&parent_args);
+		of_node_put(parent_args.np);
+
+		ret = genpd_add_subdomain(parent_pd, domain);
+		if (!ret) {
+			dev_dbg(dev, "adding PM domain %s as subdomain of %s\n",
+				domain->name, parent_pd->name);
+			return parent_pd;
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(genpd_dev_pm_attach_subdomain);
+
+/**
+ * genpd_dev_pm_detach_subdomain - Detatch a PM domain from its parent domain
+ * @domain: The PM subdomain to detach
+ * @parent: The parent PM domain
+ * @dev: The device being attached to the PM subdomain.
+ *
+ * Remove @domain from @parent.
+ * Intended to cleanup after genpd_dev_pm_attach_subdomain()
+ */
+int genpd_dev_pm_detach_subdomain(struct generic_pm_domain *domain,
+				  struct generic_pm_domain *parent,
+				  struct device *dev)
+{
+	return pm_genpd_remove_subdomain(parent, domain);
+}
+EXPORT_SYMBOL_GPL(genpd_dev_pm_detach_subdomain);
+
 static const struct of_device_id idle_state_match[] = {
 	{ .compatible = "domain-idle-state", },
 	{ }
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index cf4b11be3709..5d7eb3ae59dd 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -410,6 +410,11 @@ struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 					 unsigned int index);
 struct device *genpd_dev_pm_attach_by_name(struct device *dev,
 					   const char *name);
+struct generic_pm_domain *genpd_dev_pm_attach_subdomain(struct generic_pm_domain *domain,
+							struct device *dev);
+int genpd_dev_pm_detach_subdomain(struct generic_pm_domain *domain,
+				  struct generic_pm_domain *parent,
+				  struct device *dev);
 #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
 static inline int of_genpd_add_provider_simple(struct device_node *np,
 					struct generic_pm_domain *genpd)
@@ -466,6 +471,12 @@ static inline struct device *genpd_dev_pm_attach_by_name(struct device *dev,
 	return NULL;
 }
 
+static inline
+struct generic_pm_domain *genpd_dev_pm_attach_subdomain(struct generic_pm_domain *domain,
+							struct device *dev)
+{
+	return NULL;
+}
 static inline
 struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
 {
-- 
2.49.0