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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 | |
14 | struct device; |
15 | |
16 | /* |
17 | * The base API. |
18 | */ |
19 | |
20 | |
21 | /* |
22 | * struct clk - an machine class defined object / cookie. |
23 | */ |
24 | struct 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 | */ |
41 | struct 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 | */ |
51 | int 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 | */ |
65 | void 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 | */ |
72 | unsigned 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 | */ |
84 | void 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 | */ |
99 | long 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 | */ |
108 | int 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 | */ |
117 | int 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 | */ |
126 | struct 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 | */ |
143 | struct 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 | */ |
155 | int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, |
156 | struct device *dev); |
157 | |
158 | #endif |
159 |
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