summaryrefslogtreecommitdiffstats
path: root/include/asm-arm/hardware/clock.h
blob: 5c5689409a4b59ad3bb508fbcbdf35c83036da67 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/*
 *  linux/include/asm-arm/hardware/clock.h
 *
 *  Copyright (C) 2004 ARM Limited.
 *  Written by Deep Blue Solutions Limited.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef ASMARM_CLOCK_H
#define ASMARM_CLOCK_H

struct device;

/*
 * The base API.
 */


/*
 * struct clk - an machine class defined object / cookie.
 */
struct clk;

/**
 * clk_get - lookup and obtain a reference to a clock producer.
 * @dev: device for clock "consumer"
 * @id: clock comsumer ID
 *
 * Returns a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  (IOW, @id may be identical strings, but
 * clk_get may return different clock producers depending on @dev.)
 *
 * Drivers must assume that the clock source is not enabled.
 */
struct clk *clk_get(struct device *dev, const char *id);

/**
 * clk_enable - inform the system when the clock source should be running.
 * @clk: clock source
 *
 * If the clock can not be enabled/disabled, this should return success.
 *
 * Returns success (0) or negative errno.
 */
int clk_enable(struct clk *clk);

/**
 * clk_disable - inform the system when the clock source is no longer required.
 * @clk: clock source
 *
 * Inform the system that a clock source is no longer required by
 * a driver and may be shut down.
 *
 * Implementation detail: if the clock source is shared between
 * multiple drivers, clk_enable() calls must be balanced by the
 * same number of clk_disable() calls for the clock source to be
 * disabled.
 */
void clk_disable(struct clk *clk);

/**
 * clk_use - increment the use count
 * @clk: clock source
 *
 * Returns success (0) or negative errno.
 */
int clk_use(struct clk *clk);

/**
 * clk_unuse - decrement the use count
 * @clk: clock source
 */
void clk_unuse(struct clk *clk);

/**
 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
 *		  This is only valid once the clock source has been enabled.
 * @clk: clock source
 */
unsigned long clk_get_rate(struct clk *clk);

/**
 * clk_put	- "free" the clock source
 * @clk: clock source
 *
 * Note: drivers must ensure that all clk_enable calls made on this
 * clock source are balanced by clk_disable calls prior to calling
 * this function.
 */
void clk_put(struct clk *clk);


/*
 * The remaining APIs are optional for machine class support.
 */


/**
 * clk_round_rate - adjust a rate to the exact rate a clock can provide
 * @clk: clock source
 * @rate: desired clock rate in Hz
 *
 * Returns rounded clock rate in Hz, or negative errno.
 */
long clk_round_rate(struct clk *clk, unsigned long rate);
 
/**
 * clk_set_rate - set the clock rate for a clock source
 * @clk: clock source
 * @rate: desired clock rate in Hz
 *
 * Returns success (0) or negative errno.
 */
int clk_set_rate(struct clk *clk, unsigned long rate);
 
/**
 * clk_set_parent - set the parent clock source for this clock
 * @clk: clock source
 * @parent: parent clock source
 *
 * Returns success (0) or negative errno.
 */
int clk_set_parent(struct clk *clk, struct clk *parent);

/**
 * clk_get_parent - get the parent clock source for this clock
 * @clk: clock source
 *
 * Returns struct clk corresponding to parent clock source, or
 * valid IS_ERR() condition containing errno.
 */
struct clk *clk_get_parent(struct clk *clk);

#endif