clkdev: add possibility to get a clock based on the device name

This adds clk_get_sys to get a clock without the associated struct
device.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/common/clkdev.c

@@ -62,9 +62,8 @@ static struct clk *clk_find(const char *dev_id, const char *con_id)
 	return clk;
 }
 
-struct clk *clk_get(struct device *dev, const char *con_id)
+struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 {
-	const char *dev_id = dev ? dev_name(dev) : NULL;
 	struct clk *clk;
 
 	mutex_lock(&clocks_mutex);
@@ -75,6 +74,14 @@ struct clk *clk_get(struct device *dev, const char *con_id)
 
 	return clk ? clk : ERR_PTR(-ENOENT);
 }
+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;
+
+	return clk_get_sys(dev_id, con_id);
+}
 EXPORT_SYMBOL(clk_get);
 
 void clk_put(struct clk *clk)

include/linux/clk.h

@@ -125,4 +125,21 @@ int clk_set_parent(struct clk *clk, struct clk *parent);
  */
 struct clk *clk_get_parent(struct clk *clk);
 
+/**
+ * clk_get_sys - get a clock based upon the device name
+ * @dev_id: device name
+ * @con_id: connection ID
+ *
+ * Returns a struct clk corresponding to the clock producer, or
+ * valid IS_ERR() condition containing errno.  The implementation
+ * uses @dev_id and @con_id to determine the clock consumer, and
+ * thereby the clock producer. In contrast to clk_get() this function
+ * takes the device name instead of the device itself for identification.
+ *
+ * Drivers must assume that the clock source is not enabled.
+ *
+ * clk_get_sys should not be called from within interrupt context.
+ */
+struct clk *clk_get_sys(const char *dev_id, const char *con_id);
+
 #endif