clk: add of_clk_src_onecell_get() support

For those SoCs that have hundreds of clock outputs, their clock
DT bindings could reasonably define #clock-cells as 1 and require
the client device specify the index of the clock it consumes in the
cell of its "clocks" phandle.

Add a generic of_clk_src_onecell_get() function for this purpose.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

2 files changed, 19 insertions, 0 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index d9cbae06549..56e4495ebeb 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1587,6 +1587,20 @@ struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
 }
 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
 
+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
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 1b15307cd46..c1273158292 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -361,6 +361,11 @@ int of_clk_add_provider(struct device_node *np,
 void of_clk_del_provider(struct device_node *np);
 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
                                   void *data);
+struct clk_onecell_data {
+        struct clk **clks;
+        unsigned int clk_num;
+};
+struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data);
 const char *of_clk_get_parent_name(struct device_node *np, int index);
 void of_clk_init(const struct of_device_id *matches);