clk: add clock lookup from devicetree

Taken from the Linuxkernel with some small adjustments for barebox.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 97 insertions, 0 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 690a0c63da..7ec3d93787 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -16,6 +16,7 @@
  */
 #include <common.h>
 #include <errno.h>
+#include <malloc.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 
@@ -253,6 +254,102 @@ int clk_is_enabled_always(struct clk *clk)
 	return 1;
 }
 
+#if defined(CONFIG_OFTREE) && defined(CONFIG_COMMON_CLK_OF_PROVIDER)
+/**
+ * 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);
+
+struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
+{
+	struct clk_onecell_data *clk_data = data;
+	unsigned int idx = clkspec->args[0];
+
+	if (idx >= clk_data->clk_num) {
+		pr_err("%s: invalid clock index %d\n", __func__, idx);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return clk_data->clks[idx];
+}
+EXPORT_SYMBOL_GPL(of_clk_src_onecell_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 = np;
+	cp->data = data;
+	cp->get = clk_src_get;
+
+	list_add(&cp->link, &of_clk_providers);
+	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;
+
+	list_for_each_entry(cp, &of_clk_providers, link) {
+		if (cp->node == np) {
+			list_del(&cp->link);
+			kfree(cp);
+			break;
+		}
+	}
+}
+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 */
+	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;
+	}
+
+	return clk;
+}
+#endif
+
 static void dump_one(struct clk *clk, int verbose, int indent)
 {
 	struct clk *c;