clk: fix clk_get on of_clk_get_by_name return check

[mirror_ubuntu-bionic-kernel.git] / drivers / clk / clkdev.c

diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index c535cf8c5770f2bd154f391ade6fcd9f7fa888d2..69085e02bd58f3ea067ef45af84f0e6be08e16f0 100644 (file)
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -19,10 +19,80 @@
 #include <linux/mutex.h>
 #include <linux/clk.h>
 #include <linux/clkdev.h>
+#include <linux/of.h>
 
 static LIST_HEAD(clocks);
 static DEFINE_MUTEX(clocks_mutex);
 
+#ifdef CONFIG_OF
+struct clk *of_clk_get(struct device_node *np, int index)
+{
+       struct of_phandle_args clkspec;
+       struct clk *clk;
+       int rc;
+
+       if (index < 0)
+               return ERR_PTR(-EINVAL);
+
+       rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
+                                       &clkspec);
+       if (rc)
+               return ERR_PTR(rc);
+
+       clk = of_clk_get_from_provider(&clkspec);
+       of_node_put(clkspec.np);
+       return clk;
+}
+EXPORT_SYMBOL(of_clk_get);
+
+/**
+ * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
+ * @np: pointer to clock consumer node
+ * @name: name of consumer's clock input, or NULL for the first clock reference
+ *
+ * This function parses the clocks and clock-names properties,
+ * and uses them to look up the struct clk from the registered list of clock
+ * providers.
+ */
+struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
+{
+       struct clk *clk = ERR_PTR(-ENOENT);
+
+       /* Walk up the tree of devices looking for a clock that matches */
+       while (np) {
+               int index = 0;
+
+               /*
+                * For named clocks, first look up the name in the
+                * "clock-names" property.  If it cannot be found, then
+                * index will be an error code, and of_clk_get() will fail.
+                */
+               if (name)
+                       index = of_property_match_string(np, "clock-names", name);
+               clk = of_clk_get(np, index);
+               if (!IS_ERR(clk))
+                       break;
+               else if (name && index >= 0) {
+                       pr_err("ERROR: could not get clock %s:%s(%i)\n",
+                               np->full_name, name ? name : "", index);
+                       return clk;
+               }
+
+               /*
+                * No matching clock found on this node.  If the parent node
+                * has a "clock-ranges" property, then we can try one of its
+                * clocks.
+                */
+               np = np->parent;
+               if (np && !of_get_property(np, "clock-ranges", NULL))
+                       break;
+       }
+
+       return clk;
+}
+EXPORT_SYMBOL(of_clk_get_by_name);
+#endif
+
 /*
  * Find the correct struct clk for the device and connection ID.
  * We do slightly fuzzy matching here:
@@ -83,6 +153,13 @@ EXPORT_SYMBOL(clk_get_sys);
 struct clk *clk_get(struct device *dev, const char *con_id)
 {
        const char *dev_id = dev ? dev_name(dev) : NULL;
+       struct clk *clk;
+
+       if (dev) {
+               clk = of_clk_get_by_name(dev->of_node, con_id);
+               if (!IS_ERR(clk) && __clk_get(clk))
+                       return clk;
+       }
 
        return clk_get_sys(dev_id, con_id);
 }