PM / Domains: Add new helper functions for device-tree

Ideally, if we are returning a reference to a PM domain via a call to
of_genpd_get_from_provider(), then we should keep track of such
references via a reference count. The reference count could then be used
to determine if a PM domain can be safely removed. Alternatively, it is
possible to avoid such external references by providing APIs to access
the PM domain and hence, eliminate any calls to
of_genpd_get_from_provider().

Add new helper functions for adding a device and a subdomain to a PM
domain when using device-tree, so that external calls to
of_genpd_get_from_provider() can be removed.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 058c8b6..e12d3a8 100644 (file)
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1502,6 +1502,52 @@ struct generic_pm_domain *of_genpd_get_from_provider(
 EXPORT_SYMBOL_GPL(of_genpd_get_from_provider);
 
 /**
+ * of_genpd_add_device() - Add a device to an I/O PM domain
+ * @genpdspec: OF phandle args to use for look-up PM domain
+ * @dev: Device to be added.
+ *
+ * Looks-up an I/O PM domain based upon phandle args provided and adds
+ * the device to the PM domain. Returns a negative error code on failure.
+ */
+int of_genpd_add_device(struct of_phandle_args *genpdspec, struct device *dev)
+{
+       struct generic_pm_domain *genpd;
+
+       genpd = of_genpd_get_from_provider(genpdspec);
+       if (IS_ERR(genpd))
+               return PTR_ERR(genpd);
+
+       return pm_genpd_add_device(genpd, dev);
+}
+EXPORT_SYMBOL_GPL(of_genpd_add_device);
+
+/**
+ * of_genpd_add_subdomain - Add a subdomain to an I/O PM domain.
+ * @parent_spec: OF phandle args to use for parent PM domain look-up
+ * @subdomain_spec: OF phandle args to use for subdomain look-up
+ *
+ * Looks-up a parent PM domain and subdomain based upon phandle args
+ * provided and adds the subdomain to the parent PM domain. Returns a
+ * negative error code on failure.
+ */
+int of_genpd_add_subdomain(struct of_phandle_args *parent_spec,
+                          struct of_phandle_args *subdomain_spec)
+{
+       struct generic_pm_domain *parent, *subdomain;
+
+       parent = of_genpd_get_from_provider(parent_spec);
+       if (IS_ERR(parent))
+               return PTR_ERR(parent);
+
+       subdomain = of_genpd_get_from_provider(subdomain_spec);
+       if (IS_ERR(subdomain))
+               return PTR_ERR(subdomain);
+
+       return pm_genpd_add_subdomain(parent, subdomain);
+}
+EXPORT_SYMBOL_GPL(of_genpd_add_subdomain);
+
+/**
  * genpd_dev_pm_detach - Detach a device from its PM domain.
  * @dev: Device to detach.
  * @power_off: Currently not used

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 31fec85..e1964a2 100644 (file)
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -208,6 +208,10 @@ struct generic_pm_domain *__of_genpd_xlate_simple(
 struct generic_pm_domain *__of_genpd_xlate_onecell(
                                        struct of_phandle_args *genpdspec,
                                        void *data);
+extern int of_genpd_add_device(struct of_phandle_args *args,
+                              struct device *dev);
+extern int of_genpd_add_subdomain(struct of_phandle_args *parent,
+                                 struct of_phandle_args *new_subdomain);
 
 int genpd_dev_pm_attach(struct device *dev);
 #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
@@ -227,6 +231,18 @@ static inline struct generic_pm_domain *of_genpd_get_from_provider(
 #define __of_genpd_xlate_simple                NULL
 #define __of_genpd_xlate_onecell       NULL
 
+static inline int of_genpd_add_device(struct of_phandle_args *args,
+                                     struct device *dev)
+{
+       return -ENODEV;
+}
+
+static inline int of_genpd_add_subdomain(struct of_phandle_args *parent,
+                                        struct of_phandle_args *new_subdomain)
+{
+       return -ENODEV;
+}
+
 static inline int genpd_dev_pm_attach(struct device *dev)
 {
        return -ENODEV;