[U-Boot] [PATCH 01/50] dm: clk: Add support for decoding clocks from the device tree

[Simon Glass]

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 at chromium.org>
---

 drivers/clk/clk-uclass.c | 28 ++++++++++++++++++++++++++++
 include/clk.h            | 15 +++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 8078b0f..a205b26 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -12,6 +12,8 @@
 #include <dm/lists.h>
 #include <dm/root.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 ulong clk_get_rate(struct udevice *dev)
 {
 	struct clk_ops *ops = clk_get_ops(dev);
@@ -62,6 +64,32 @@ int clk_get_id(struct udevice *dev, int args_count, uint32_t *args)
 	return ops->get_id(dev, args_count, args);
 }
 
+int clk_get_by_index(struct udevice *dev, int index, struct udevice **clk_devp,
+		     int *periphp)
+{
+	struct fdtdec_phandle_args args;
+	int ret;
+
+	ret = fdtdec_parse_phandle_with_args(gd->fdt_blob, dev->of_offset,
+					     "clocks", "#clock-cells", 0, index,
+					     &args);
+	if (ret) {
+		debug("%s: fdtdec_parse_phandle_with_args failed: err=%d\n",
+		      __func__, ret);
+		return ret;
+	}
+
+	ret = uclass_get_device_by_of_offset(UCLASS_CLK, args.node, clk_devp);
+	if (ret) {
+		debug("%s: uclass_get_device_by_of_offset failed: err=%d\n",
+		      __func__, ret);
+		return ret;
+	}
+	*periphp = args.args_count > 0 ? args.args[0] : -1;
+
+	return 0;
+}
+
 UCLASS_DRIVER(clk) = {
 	.id		= UCLASS_CLK,
 	.name		= "clk",
diff --git a/include/clk.h b/include/clk.h
index ce2db41..b77c788 100644
--- a/include/clk.h
+++ b/include/clk.h
@@ -150,4 +150,19 @@ static inline int fdt_clk_get(const void *fdt, int nodeoffset, int index,
 }
 #endif
 
+/**
+ * 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
+ * @periphp:	Returns peripheral ID for the device to control. This is the
+ *		first argument after the clock node phandle.
+ * @return 0 if OK, or -ve error code
+ */
+int clk_get_by_index(struct udevice *dev, int index, struct udevice **clk_devp,
+		     int *periphp);
 #endif /* _CLK_H_ */
-- 
2.6.0.rc2.230.g3dd15c0