Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
[sfrench/cifs-2.6.git] / drivers / of / base.c
index 8d173fb3552a11174c490522dfd53bbce8e04e58..ae03b1218b06e5f5da9111fecf09cd30ca3d8691 100644 (file)
@@ -415,6 +415,42 @@ int of_cpu_node_to_id(struct device_node *cpu_node)
 }
 EXPORT_SYMBOL(of_cpu_node_to_id);
 
+/**
+ * of_get_cpu_state_node - Get CPU's idle state node at the given index
+ *
+ * @cpu_node: The device node for the CPU
+ * @index: The index in the list of the idle states
+ *
+ * Two generic methods can be used to describe a CPU's idle states, either via
+ * a flattened description through the "cpu-idle-states" binding or via the
+ * hierarchical layout, using the "power-domains" and the "domain-idle-states"
+ * bindings. This function check for both and returns the idle state node for
+ * the requested index.
+ *
+ * In case an idle state node is found at @index, the refcount is incremented
+ * for it, so call of_node_put() on it when done. Returns NULL if not found.
+ */
+struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
+                                         int index)
+{
+       struct of_phandle_args args;
+       int err;
+
+       err = of_parse_phandle_with_args(cpu_node, "power-domains",
+                                       "#power-domain-cells", 0, &args);
+       if (!err) {
+               struct device_node *state_node =
+                       of_parse_phandle(args.np, "domain-idle-states", index);
+
+               of_node_put(args.np);
+               if (state_node)
+                       return state_node;
+       }
+
+       return of_parse_phandle(cpu_node, "cpu-idle-states", index);
+}
+EXPORT_SYMBOL(of_get_cpu_state_node);
+
 /**
  * __of_device_is_compatible() - Check if the node matches given constraints
  * @device: pointer to node