dm: clk: Add support for decoding clocks from the device tree
Add a method which can locate a clock for a device, given its index. This
uses the normal device tree bindings to return the clock device and the
first argument which is normally used as a peripheral ID in U-Boot.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/include/clk.h b/include/clk.h
index 941808a..ca20c3d 100644
--- a/include/clk.h
+++ b/include/clk.h
@@ -8,6 +8,7 @@
#ifndef _CLK_H_
#define _CLK_H_
+#include <errno.h>
#include <linux/types.h>
struct udevice;
@@ -105,4 +106,27 @@
*/
ulong clk_set_periph_rate(struct udevice *dev, int periph, ulong rate);
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+/**
+ * clk_get_by_index() - look up a clock referenced by a device
+ *
+ * Parse a device's 'clocks' list, returning information on the indexed clock,
+ * ensuring that it is activated.
+ *
+ * @dev: Device containing the clock reference
+ * @index: Clock index to return (0 = first)
+ * @clk_devp: Returns clock device
+ * @return: Peripheral ID for the device to control. This is the first
+ * argument after the clock node phandle. If there is no arguemnt,
+ * returns 0. Return -ve error code on any error
+ */
+int clk_get_by_index(struct udevice *dev, int index, struct udevice **clk_devp);
+#else
+static inline int clk_get_by_index(struct udevice *dev, int index,
+ struct udevice **clk_devp)
+{
+ return -ENOSYS;
+}
+#endif
+
#endif /* _CLK_H_ */