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1/*
2 * linux/include/asm-arm/hardware/clock.h
3 *
4 * Copyright (C) 2004 ARM Limited.
5 * Written by Deep Blue Solutions Limited.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11#ifndef ASMARM_CLOCK_H
12#define ASMARM_CLOCK_H
13
14struct device;
15
16/*
17 * The base API.
18 */
19
20
21/*
22 * struct clk - an machine class defined object / cookie.
23 */
24struct clk;
25
26/**
27 * clk_get - lookup and obtain a reference to a clock producer.
28 * @dev: device for clock "consumer"
29 * @id: clock comsumer ID
30 *
31 * Returns a struct clk corresponding to the clock producer, or
32 * valid IS_ERR() condition containing errno. The implementation
33 * uses @dev and @id to determine the clock consumer, and thereby
34 * the clock producer. (IOW, @id may be identical strings, but
35 * clk_get may return different clock producers depending on @dev.)
36 */
37struct clk *clk_get(struct device *dev, const char *id);
38
39/**
40 * clk_enable - inform the system when the clock source should be running.
41 * @clk: clock source
42 *
43 * If the clock can not be enabled/disabled, this should return success.
44 *
45 * Returns success (0) or negative errno.
46 */
47int clk_enable(struct clk *clk);
48
49/**
50 * clk_disable - inform the system when the clock source is no longer required.
51 * @clk: clock source
52 */
53void clk_disable(struct clk *clk);
54
55/**
56 * clk_use - increment the use count
57 * @clk: clock source
58 *
59 * Returns success (0) or negative errno.
60 */
61int clk_use(struct clk *clk);
62
63/**
64 * clk_unuse - decrement the use count
65 * @clk: clock source
66 */
67void clk_unuse(struct clk *clk);
68
69/**
70 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
71 * This is only valid once the clock source has been enabled.
72 * @clk: clock source
73 */
74unsigned long clk_get_rate(struct clk *clk);
75
76/**
77 * clk_put - "free" the clock source
78 * @clk: clock source
79 */
80void clk_put(struct clk *clk);
81
82
83/*
84 * The remaining APIs are optional for machine class support.
85 */
86
87
88/**
89 * clk_round_rate - adjust a rate to the exact rate a clock can provide
90 * @clk: clock source
91 * @rate: desired clock rate in Hz
92 *
93 * Returns rounded clock rate in Hz, or negative errno.
94 */
95long clk_round_rate(struct clk *clk, unsigned long rate);
96
97/**
98 * clk_set_rate - set the clock rate for a clock source
99 * @clk: clock source
100 * @rate: desired clock rate in Hz
101 *
102 * Returns success (0) or negative errno.
103 */
104int clk_set_rate(struct clk *clk, unsigned long rate);
105
106/**
107 * clk_set_parent - set the parent clock source for this clock
108 * @clk: clock source
109 * @parent: parent clock source
110 *
111 * Returns success (0) or negative errno.
112 */
113int clk_set_parent(struct clk *clk, struct clk *parent);
114
115/**
116 * clk_get_parent - get the parent clock source for this clock
117 * @clk: clock source
118 *
119 * Returns struct clk corresponding to parent clock source, or
120 * valid IS_ERR() condition containing errno.
121 */
122struct clk *clk_get_parent(struct clk *clk);
123
124#endif