1 files changed, 164 insertions, 18 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 687b00d67c8a..c87fdd710560 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -16,6 +16,7 @@
 #include <linux/err.h>
 #include <linux/list.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 static DEFINE_SPINLOCK(enable_lock);
 static DEFINE_MUTEX(prepare_lock);
@@ -850,18 +851,21 @@ static void clk_change_rate(struct clk *clk)
 {
 	struct clk *child;
 	unsigned long old_rate;
+	unsigned long best_parent_rate = 0;
 	struct hlist_node *tmp;
 
 	old_rate = clk->rate;
 
+	if (clk->parent)
+		best_parent_rate = clk->parent->rate;
+
 	if (clk->ops->set_rate)
-		clk->ops->set_rate(clk->hw, clk->new_rate, clk->parent->rate);
+		clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
 
 	if (clk->ops->recalc_rate)
-		clk->rate = clk->ops->recalc_rate(clk->hw,
-				clk->parent->rate);
+		clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
 	else
-		clk->rate = clk->parent->rate;
+		clk->rate = best_parent_rate;
 
 	if (clk->notifier_count && old_rate != clk->rate)
 		__clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
@@ -999,7 +1003,7 @@ static struct clk *__clk_init_parent(struct clk *clk)
 
 	if (!clk->parents)
 		clk->parents =
-			kmalloc((sizeof(struct clk*) * clk->num_parents),
+			kzalloc((sizeof(struct clk*) * clk->num_parents),
 					GFP_KERNEL);
 
 	if (!clk->parents)
@@ -1064,21 +1068,24 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
 
 	old_parent = clk->parent;
 
-	/* find index of new parent clock using cached parent ptrs */
-	for (i = 0; i < clk->num_parents; i++)
-		if (clk->parents[i] == parent)
-			break;
+	if (!clk->parents)
+		clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
+								GFP_KERNEL);
 
 	/*
-	 * find index of new parent clock using string name comparison
-	 * also try to cache the parent to avoid future calls to __clk_lookup
+	 * find index of new parent clock using cached parent ptrs,
+	 * or if not yet cached, use string name comparison and cache
+	 * them now to avoid future calls to __clk_lookup.
 	 */
-	if (i == clk->num_parents)
-		for (i = 0; i < clk->num_parents; i++)
-			if (!strcmp(clk->parent_names[i], parent->name)) {
+	for (i = 0; i < clk->num_parents; i++) {
+		if (clk->parents && clk->parents[i] == parent)
+			break;
+		else if (!strcmp(clk->parent_names[i], parent->name)) {
+			if (clk->parents)
 				clk->parents[i] = __clk_lookup(parent->name);
-				break;
-			}
+			break;
+		}
+	}
 
 	if (i == clk->num_parents) {
 		pr_debug("%s: clock %s is not a possible parent of clock %s\n",
@@ -1229,8 +1236,8 @@ int __clk_init(struct device *dev, struct clk *clk)
 	 * If clk->parents is not NULL we skip this entire block.  This allows
 	 * for clock drivers to statically initialize clk->parents.
 	 */
-	if (clk->num_parents && !clk->parents) {
-		clk->parents = kmalloc((sizeof(struct clk*) * clk->num_parents),
+	if (clk->num_parents > 1 && !clk->parents) {
+		clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
 				GFP_KERNEL);
 		/*
 		 * __clk_lookup returns NULL for parents that have not been
@@ -1544,3 +1551,142 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
+
+#ifdef CONFIG_OF
+/**
+ * struct of_clk_provider - Clock provider registration structure
+ * @link: Entry in global list of clock providers
+ * @node: Pointer to device tree node of clock provider
+ * @get: Get clock callback.  Returns NULL or a struct clk for the
+ *       given clock specifier
+ * @data: context pointer to be passed into @get callback
+ */
+struct of_clk_provider {
+	struct list_head link;
+
+	struct device_node *node;
+	struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
+	void *data;
+};
+
+static LIST_HEAD(of_clk_providers);
+static DEFINE_MUTEX(of_clk_lock);
+
+struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
+				     void *data)
+{
+	return data;
+}
+EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
+
+/**
+ * of_clk_add_provider() - Register a clock provider for a node
+ * @np: Device node pointer associated with clock provider
+ * @clk_src_get: callback for decoding clock
+ * @data: context pointer for @clk_src_get callback.
+ */
+int of_clk_add_provider(struct device_node *np,
+			struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
+						   void *data),
+			void *data)
+{
+	struct of_clk_provider *cp;
+
+	cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
+	if (!cp)
+		return -ENOMEM;
+
+	cp->node = of_node_get(np);
+	cp->data = data;
+	cp->get = clk_src_get;
+
+	mutex_lock(&of_clk_lock);
+	list_add(&cp->link, &of_clk_providers);
+	mutex_unlock(&of_clk_lock);
+	pr_debug("Added clock from %s\n", np->full_name);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_clk_add_provider);
+
+/**
+ * of_clk_del_provider() - Remove a previously registered clock provider
+ * @np: Device node pointer associated with clock provider
+ */
+void of_clk_del_provider(struct device_node *np)
+{
+	struct of_clk_provider *cp;
+
+	mutex_lock(&of_clk_lock);
+	list_for_each_entry(cp, &of_clk_providers, link) {
+		if (cp->node == np) {
+			list_del(&cp->link);
+			of_node_put(cp->node);
+			kfree(cp);
+			break;
+		}
+	}
+	mutex_unlock(&of_clk_lock);
+}
+EXPORT_SYMBOL_GPL(of_clk_del_provider);
+
+struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
+{
+	struct of_clk_provider *provider;
+	struct clk *clk = ERR_PTR(-ENOENT);
+
+	/* Check if we have such a provider in our array */
+	mutex_lock(&of_clk_lock);
+	list_for_each_entry(provider, &of_clk_providers, link) {
+		if (provider->node == clkspec->np)
+			clk = provider->get(clkspec, provider->data);
+		if (!IS_ERR(clk))
+			break;
+	}
+	mutex_unlock(&of_clk_lock);
+
+	return clk;
+}
+
+const char *of_clk_get_parent_name(struct device_node *np, int index)
+{
+	struct of_phandle_args clkspec;
+	const char *clk_name;
+	int rc;
+
+	if (index < 0)
+		return NULL;
+
+	rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
+					&clkspec);
+	if (rc)
+		return NULL;
+
+	if (of_property_read_string_index(clkspec.np, "clock-output-names",
+					  clkspec.args_count ? clkspec.args[0] : 0,
+					  &clk_name) < 0)
+		clk_name = clkspec.np->name;
+
+	of_node_put(clkspec.np);
+	return clk_name;
+}
+EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
+
+/**
+ * of_clk_init() - Scan and init clock providers from the DT
+ * @matches: array of compatible values and init functions for providers.
+ *
+ * This function scans the device tree for matching clock providers and
+ * calls their initialization functions
+ */
+void __init of_clk_init(const struct of_device_id *matches)
+{
+	struct device_node *np;
+
+	for_each_matching_node(np, matches) {
+		const struct of_device_id *match = of_match_node(matches, np);
+		of_clk_init_cb_t clk_init_cb = match->data;
+		clk_init_cb(np);
+	}
+}
+#endif