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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>
This commit is contained in:
Simon Glass 2016-01-20 19:43:02 -07:00
parent b21e20b255
commit e70cc43831
2 changed files with 52 additions and 0 deletions
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28
drivers/clk/clk-uclass.c
View File

@ -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",

24
include/clk.h
View File

@ -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_ */