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1da177e4 | 1 | /* |
f8ce2547 | 2 | * linux/include/linux/clk.h |
1da177e4 LT |
3 | * |
4 | * Copyright (C) 2004 ARM Limited. | |
5 | * Written by Deep Blue Solutions Limited. | |
b2476490 | 6 | * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> |
1da177e4 LT |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
686f8c5d TP |
12 | #ifndef __LINUX_CLK_H |
13 | #define __LINUX_CLK_H | |
1da177e4 | 14 | |
40d3e0f4 | 15 | #include <linux/kernel.h> |
b2476490 | 16 | #include <linux/notifier.h> |
40d3e0f4 | 17 | |
1da177e4 LT |
18 | struct device; |
19 | ||
b2476490 MT |
20 | struct clk; |
21 | ||
22 | #ifdef CONFIG_COMMON_CLK | |
23 | ||
24 | /** | |
25 | * DOC: clk notifier callback types | |
26 | * | |
27 | * PRE_RATE_CHANGE - called immediately before the clk rate is changed, | |
28 | * to indicate that the rate change will proceed. Drivers must | |
29 | * immediately terminate any operations that will be affected by the | |
30 | * rate change. Callbacks may either return NOTIFY_DONE or | |
31 | * NOTIFY_STOP. | |
32 | * | |
33 | * ABORT_RATE_CHANGE: called if the rate change failed for some reason | |
34 | * after PRE_RATE_CHANGE. In this case, all registered notifiers on | |
35 | * the clk will be called with ABORT_RATE_CHANGE. Callbacks must | |
36 | * always return NOTIFY_DONE. | |
37 | * | |
38 | * POST_RATE_CHANGE - called after the clk rate change has successfully | |
39 | * completed. Callbacks must always return NOTIFY_DONE. | |
40 | * | |
1da177e4 | 41 | */ |
b2476490 MT |
42 | #define PRE_RATE_CHANGE BIT(0) |
43 | #define POST_RATE_CHANGE BIT(1) | |
44 | #define ABORT_RATE_CHANGE BIT(2) | |
1da177e4 | 45 | |
b2476490 MT |
46 | /** |
47 | * struct clk_notifier - associate a clk with a notifier | |
48 | * @clk: struct clk * to associate the notifier with | |
49 | * @notifier_head: a blocking_notifier_head for this clk | |
50 | * @node: linked list pointers | |
51 | * | |
52 | * A list of struct clk_notifier is maintained by the notifier code. | |
53 | * An entry is created whenever code registers the first notifier on a | |
54 | * particular @clk. Future notifiers on that @clk are added to the | |
55 | * @notifier_head. | |
56 | */ | |
57 | struct clk_notifier { | |
58 | struct clk *clk; | |
59 | struct srcu_notifier_head notifier_head; | |
60 | struct list_head node; | |
61 | }; | |
1da177e4 | 62 | |
b2476490 MT |
63 | /** |
64 | * struct clk_notifier_data - rate data to pass to the notifier callback | |
65 | * @clk: struct clk * being changed | |
66 | * @old_rate: previous rate of this clk | |
67 | * @new_rate: new rate of this clk | |
68 | * | |
69 | * For a pre-notifier, old_rate is the clk's rate before this rate | |
70 | * change, and new_rate is what the rate will be in the future. For a | |
71 | * post-notifier, old_rate and new_rate are both set to the clk's | |
72 | * current rate (this was done to optimize the implementation). | |
1da177e4 | 73 | */ |
b2476490 MT |
74 | struct clk_notifier_data { |
75 | struct clk *clk; | |
76 | unsigned long old_rate; | |
77 | unsigned long new_rate; | |
78 | }; | |
79 | ||
80 | int clk_notifier_register(struct clk *clk, struct notifier_block *nb); | |
81 | ||
82 | int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb); | |
83 | ||
7e87aed9 | 84 | #endif |
1da177e4 LT |
85 | |
86 | /** | |
87 | * clk_get - lookup and obtain a reference to a clock producer. | |
88 | * @dev: device for clock "consumer" | |
ea3f4eac | 89 | * @id: clock comsumer ID |
1da177e4 LT |
90 | * |
91 | * Returns a struct clk corresponding to the clock producer, or | |
ea3f4eac RK |
92 | * valid IS_ERR() condition containing errno. The implementation |
93 | * uses @dev and @id to determine the clock consumer, and thereby | |
94 | * the clock producer. (IOW, @id may be identical strings, but | |
95 | * clk_get may return different clock producers depending on @dev.) | |
f47fc0ac RK |
96 | * |
97 | * Drivers must assume that the clock source is not enabled. | |
f7ad160b AR |
98 | * |
99 | * clk_get should not be called from within interrupt context. | |
1da177e4 LT |
100 | */ |
101 | struct clk *clk_get(struct device *dev, const char *id); | |
102 | ||
40d3e0f4 RK |
103 | /** |
104 | * clk_prepare - prepare a clock source | |
105 | * @clk: clock source | |
106 | * | |
107 | * This prepares the clock source for use. | |
108 | * | |
109 | * Must not be called from within atomic context. | |
110 | */ | |
111 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
112 | int clk_prepare(struct clk *clk); | |
113 | #else | |
114 | static inline int clk_prepare(struct clk *clk) | |
115 | { | |
116 | might_sleep(); | |
117 | return 0; | |
118 | } | |
119 | #endif | |
120 | ||
1da177e4 LT |
121 | /** |
122 | * clk_enable - inform the system when the clock source should be running. | |
123 | * @clk: clock source | |
124 | * | |
125 | * If the clock can not be enabled/disabled, this should return success. | |
126 | * | |
40d3e0f4 RK |
127 | * May be called from atomic contexts. |
128 | * | |
1da177e4 LT |
129 | * Returns success (0) or negative errno. |
130 | */ | |
131 | int clk_enable(struct clk *clk); | |
132 | ||
133 | /** | |
134 | * clk_disable - inform the system when the clock source is no longer required. | |
135 | * @clk: clock source | |
f47fc0ac RK |
136 | * |
137 | * Inform the system that a clock source is no longer required by | |
138 | * a driver and may be shut down. | |
139 | * | |
40d3e0f4 RK |
140 | * May be called from atomic contexts. |
141 | * | |
f47fc0ac RK |
142 | * Implementation detail: if the clock source is shared between |
143 | * multiple drivers, clk_enable() calls must be balanced by the | |
144 | * same number of clk_disable() calls for the clock source to be | |
145 | * disabled. | |
1da177e4 LT |
146 | */ |
147 | void clk_disable(struct clk *clk); | |
148 | ||
40d3e0f4 RK |
149 | |
150 | /** | |
151 | * clk_unprepare - undo preparation of a clock source | |
152 | * @clk: clock source | |
153 | * | |
154 | * This undoes a previously prepared clock. The caller must balance | |
155 | * the number of prepare and unprepare calls. | |
156 | * | |
157 | * Must not be called from within atomic context. | |
158 | */ | |
159 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
160 | void clk_unprepare(struct clk *clk); | |
161 | #else | |
162 | static inline void clk_unprepare(struct clk *clk) | |
163 | { | |
164 | might_sleep(); | |
165 | } | |
166 | #endif | |
167 | ||
42c5d52f RZ |
168 | /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */ |
169 | static inline int clk_prepare_enable(struct clk *clk) | |
170 | { | |
171 | int ret; | |
172 | ||
173 | ret = clk_prepare(clk); | |
174 | if (ret) | |
175 | return ret; | |
176 | ret = clk_enable(clk); | |
177 | if (ret) | |
178 | clk_unprepare(clk); | |
179 | ||
180 | return ret; | |
181 | } | |
182 | ||
183 | /* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */ | |
184 | static inline void clk_disable_unprepare(struct clk *clk) | |
185 | { | |
186 | clk_disable(clk); | |
187 | clk_unprepare(clk); | |
188 | } | |
189 | ||
1da177e4 LT |
190 | /** |
191 | * clk_get_rate - obtain the current clock rate (in Hz) for a clock source. | |
192 | * This is only valid once the clock source has been enabled. | |
193 | * @clk: clock source | |
194 | */ | |
195 | unsigned long clk_get_rate(struct clk *clk); | |
196 | ||
197 | /** | |
198 | * clk_put - "free" the clock source | |
199 | * @clk: clock source | |
f47fc0ac RK |
200 | * |
201 | * Note: drivers must ensure that all clk_enable calls made on this | |
202 | * clock source are balanced by clk_disable calls prior to calling | |
203 | * this function. | |
f7ad160b AR |
204 | * |
205 | * clk_put should not be called from within interrupt context. | |
1da177e4 LT |
206 | */ |
207 | void clk_put(struct clk *clk); | |
208 | ||
209 | ||
210 | /* | |
211 | * The remaining APIs are optional for machine class support. | |
212 | */ | |
213 | ||
214 | ||
215 | /** | |
216 | * clk_round_rate - adjust a rate to the exact rate a clock can provide | |
217 | * @clk: clock source | |
218 | * @rate: desired clock rate in Hz | |
219 | * | |
220 | * Returns rounded clock rate in Hz, or negative errno. | |
221 | */ | |
222 | long clk_round_rate(struct clk *clk, unsigned long rate); | |
223 | ||
224 | /** | |
225 | * clk_set_rate - set the clock rate for a clock source | |
226 | * @clk: clock source | |
227 | * @rate: desired clock rate in Hz | |
228 | * | |
229 | * Returns success (0) or negative errno. | |
230 | */ | |
231 | int clk_set_rate(struct clk *clk, unsigned long rate); | |
232 | ||
233 | /** | |
234 | * clk_set_parent - set the parent clock source for this clock | |
235 | * @clk: clock source | |
236 | * @parent: parent clock source | |
237 | * | |
238 | * Returns success (0) or negative errno. | |
239 | */ | |
240 | int clk_set_parent(struct clk *clk, struct clk *parent); | |
241 | ||
242 | /** | |
243 | * clk_get_parent - get the parent clock source for this clock | |
244 | * @clk: clock source | |
245 | * | |
246 | * Returns struct clk corresponding to parent clock source, or | |
247 | * valid IS_ERR() condition containing errno. | |
248 | */ | |
249 | struct clk *clk_get_parent(struct clk *clk); | |
250 | ||
05fd8e73 SH |
251 | /** |
252 | * clk_get_sys - get a clock based upon the device name | |
253 | * @dev_id: device name | |
254 | * @con_id: connection ID | |
255 | * | |
256 | * Returns a struct clk corresponding to the clock producer, or | |
257 | * valid IS_ERR() condition containing errno. The implementation | |
258 | * uses @dev_id and @con_id to determine the clock consumer, and | |
259 | * thereby the clock producer. In contrast to clk_get() this function | |
260 | * takes the device name instead of the device itself for identification. | |
261 | * | |
262 | * Drivers must assume that the clock source is not enabled. | |
263 | * | |
264 | * clk_get_sys should not be called from within interrupt context. | |
265 | */ | |
266 | struct clk *clk_get_sys(const char *dev_id, const char *con_id); | |
267 | ||
c0683039 TL |
268 | /** |
269 | * clk_add_alias - add a new clock alias | |
270 | * @alias: name for clock alias | |
271 | * @alias_dev_name: device name | |
272 | * @id: platform specific clock name | |
273 | * @dev: device | |
274 | * | |
275 | * Allows using generic clock names for drivers by adding a new alias. | |
276 | * Assumes clkdev, see clkdev.h for more info. | |
277 | */ | |
278 | int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, | |
279 | struct device *dev); | |
280 | ||
1da177e4 | 281 | #endif |