Linux kernel mirror (for testing)
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1/*
2 * linux/include/linux/clk.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 __LINUX_CLK_H
12#define __LINUX_CLK_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 *
37 * Drivers must assume that the clock source is not enabled.
38 *
39 * clk_get should not be called from within interrupt context.
40 */
41struct clk *clk_get(struct device *dev, const char *id);
42
43/**
44 * clk_enable - inform the system when the clock source should be running.
45 * @clk: clock source
46 *
47 * If the clock can not be enabled/disabled, this should return success.
48 *
49 * Returns success (0) or negative errno.
50 */
51int clk_enable(struct clk *clk);
52
53/**
54 * clk_disable - inform the system when the clock source is no longer required.
55 * @clk: clock source
56 *
57 * Inform the system that a clock source is no longer required by
58 * a driver and may be shut down.
59 *
60 * Implementation detail: if the clock source is shared between
61 * multiple drivers, clk_enable() calls must be balanced by the
62 * same number of clk_disable() calls for the clock source to be
63 * disabled.
64 */
65void clk_disable(struct clk *clk);
66
67/**
68 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
69 * This is only valid once the clock source has been enabled.
70 * @clk: clock source
71 */
72unsigned long clk_get_rate(struct clk *clk);
73
74/**
75 * clk_put - "free" the clock source
76 * @clk: clock source
77 *
78 * Note: drivers must ensure that all clk_enable calls made on this
79 * clock source are balanced by clk_disable calls prior to calling
80 * this function.
81 *
82 * clk_put should not be called from within interrupt context.
83 */
84void clk_put(struct clk *clk);
85
86
87/*
88 * The remaining APIs are optional for machine class support.
89 */
90
91
92/**
93 * clk_round_rate - adjust a rate to the exact rate a clock can provide
94 * @clk: clock source
95 * @rate: desired clock rate in Hz
96 *
97 * Returns rounded clock rate in Hz, or negative errno.
98 */
99long clk_round_rate(struct clk *clk, unsigned long rate);
100
101/**
102 * clk_set_rate - set the clock rate for a clock source
103 * @clk: clock source
104 * @rate: desired clock rate in Hz
105 *
106 * Returns success (0) or negative errno.
107 */
108int clk_set_rate(struct clk *clk, unsigned long rate);
109
110/**
111 * clk_set_parent - set the parent clock source for this clock
112 * @clk: clock source
113 * @parent: parent clock source
114 *
115 * Returns success (0) or negative errno.
116 */
117int clk_set_parent(struct clk *clk, struct clk *parent);
118
119/**
120 * clk_get_parent - get the parent clock source for this clock
121 * @clk: clock source
122 *
123 * Returns struct clk corresponding to parent clock source, or
124 * valid IS_ERR() condition containing errno.
125 */
126struct clk *clk_get_parent(struct clk *clk);
127
128/**
129 * clk_get_sys - get a clock based upon the device name
130 * @dev_id: device name
131 * @con_id: connection ID
132 *
133 * Returns a struct clk corresponding to the clock producer, or
134 * valid IS_ERR() condition containing errno. The implementation
135 * uses @dev_id and @con_id to determine the clock consumer, and
136 * thereby the clock producer. In contrast to clk_get() this function
137 * takes the device name instead of the device itself for identification.
138 *
139 * Drivers must assume that the clock source is not enabled.
140 *
141 * clk_get_sys should not be called from within interrupt context.
142 */
143struct clk *clk_get_sys(const char *dev_id, const char *con_id);
144
145/**
146 * clk_add_alias - add a new clock alias
147 * @alias: name for clock alias
148 * @alias_dev_name: device name
149 * @id: platform specific clock name
150 * @dev: device
151 *
152 * Allows using generic clock names for drivers by adding a new alias.
153 * Assumes clkdev, see clkdev.h for more info.
154 */
155int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
156 struct device *dev);
157
158#endif