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authorSimon Glass <sjg@chromium.org>2016-01-20 19:43:02 -0700
committerSimon Glass <sjg@chromium.org>2016-01-21 19:47:29 -0700
commite70cc438311c753edc1f19214ffc090061e60880 (patch)
treef7ab2b660954da09ef3cbecd24fb3fa45fb8fe58
parentb21e20b255a02393727c93b1927a381ce3008fa4 (diff)
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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>
-rw-r--r--drivers/clk/clk-uclass.c28
-rw-r--r--include/clk.h24
2 files changed, 52 insertions, 0 deletions
diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 19f6f07..8a4c568 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 @@ ulong clk_set_periph_rate(struct udevice *dev, int periph, ulong rate)
return ops->set_periph_rate(dev, periph, rate);
}
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+int clk_get_by_index(struct udevice *dev, int index, struct udevice **clk_devp)
+{
+ struct fdtdec_phandle_args args;
+ int ret;
+
+ assert(*clk_devp);
+ 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;
+ }
+ return args.args_count > 0 ? args.args[0] : 0;
+}
+#endif
+
UCLASS_DRIVER(clk) = {
.id = UCLASS_CLK,
.name = "clk",
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_get_periph_rate(struct udevice *dev, int periph);
*/
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_ */