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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 | |
9f1612d3 | 15 | #include <linux/err.h> |
40d3e0f4 | 16 | #include <linux/kernel.h> |
b2476490 | 17 | #include <linux/notifier.h> |
40d3e0f4 | 18 | |
1da177e4 LT |
19 | struct device; |
20 | ||
b2476490 MT |
21 | struct clk; |
22 | ||
23 | #ifdef CONFIG_COMMON_CLK | |
24 | ||
25 | /** | |
26 | * DOC: clk notifier callback types | |
27 | * | |
28 | * PRE_RATE_CHANGE - called immediately before the clk rate is changed, | |
29 | * to indicate that the rate change will proceed. Drivers must | |
30 | * immediately terminate any operations that will be affected by the | |
fb72a059 SB |
31 | * rate change. Callbacks may either return NOTIFY_DONE, NOTIFY_OK, |
32 | * NOTIFY_STOP or NOTIFY_BAD. | |
b2476490 MT |
33 | * |
34 | * ABORT_RATE_CHANGE: called if the rate change failed for some reason | |
35 | * after PRE_RATE_CHANGE. In this case, all registered notifiers on | |
36 | * the clk will be called with ABORT_RATE_CHANGE. Callbacks must | |
fb72a059 | 37 | * always return NOTIFY_DONE or NOTIFY_OK. |
b2476490 MT |
38 | * |
39 | * POST_RATE_CHANGE - called after the clk rate change has successfully | |
fb72a059 | 40 | * completed. Callbacks must always return NOTIFY_DONE or NOTIFY_OK. |
b2476490 | 41 | * |
1da177e4 | 42 | */ |
b2476490 MT |
43 | #define PRE_RATE_CHANGE BIT(0) |
44 | #define POST_RATE_CHANGE BIT(1) | |
45 | #define ABORT_RATE_CHANGE BIT(2) | |
1da177e4 | 46 | |
b2476490 MT |
47 | /** |
48 | * struct clk_notifier - associate a clk with a notifier | |
49 | * @clk: struct clk * to associate the notifier with | |
50 | * @notifier_head: a blocking_notifier_head for this clk | |
51 | * @node: linked list pointers | |
52 | * | |
53 | * A list of struct clk_notifier is maintained by the notifier code. | |
54 | * An entry is created whenever code registers the first notifier on a | |
55 | * particular @clk. Future notifiers on that @clk are added to the | |
56 | * @notifier_head. | |
57 | */ | |
58 | struct clk_notifier { | |
59 | struct clk *clk; | |
60 | struct srcu_notifier_head notifier_head; | |
61 | struct list_head node; | |
62 | }; | |
1da177e4 | 63 | |
b2476490 MT |
64 | /** |
65 | * struct clk_notifier_data - rate data to pass to the notifier callback | |
66 | * @clk: struct clk * being changed | |
67 | * @old_rate: previous rate of this clk | |
68 | * @new_rate: new rate of this clk | |
69 | * | |
70 | * For a pre-notifier, old_rate is the clk's rate before this rate | |
71 | * change, and new_rate is what the rate will be in the future. For a | |
72 | * post-notifier, old_rate and new_rate are both set to the clk's | |
73 | * current rate (this was done to optimize the implementation). | |
1da177e4 | 74 | */ |
b2476490 MT |
75 | struct clk_notifier_data { |
76 | struct clk *clk; | |
77 | unsigned long old_rate; | |
78 | unsigned long new_rate; | |
79 | }; | |
80 | ||
81 | int clk_notifier_register(struct clk *clk, struct notifier_block *nb); | |
82 | ||
83 | int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb); | |
84 | ||
5279fc40 BB |
85 | /** |
86 | * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion) | |
87 | * for a clock source. | |
88 | * @clk: clock source | |
89 | * | |
90 | * This gets the clock source accuracy expressed in ppb. | |
91 | * A perfect clock returns 0. | |
92 | */ | |
93 | long clk_get_accuracy(struct clk *clk); | |
94 | ||
95 | #else | |
96 | ||
97 | static inline long clk_get_accuracy(struct clk *clk) | |
98 | { | |
99 | return -ENOTSUPP; | |
100 | } | |
101 | ||
7e87aed9 | 102 | #endif |
1da177e4 | 103 | |
93abe8e4 VK |
104 | /** |
105 | * clk_prepare - prepare a clock source | |
106 | * @clk: clock source | |
107 | * | |
108 | * This prepares the clock source for use. | |
109 | * | |
110 | * Must not be called from within atomic context. | |
111 | */ | |
112 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
113 | int clk_prepare(struct clk *clk); | |
114 | #else | |
115 | static inline int clk_prepare(struct clk *clk) | |
116 | { | |
117 | might_sleep(); | |
118 | return 0; | |
119 | } | |
120 | #endif | |
121 | ||
122 | /** | |
123 | * clk_unprepare - undo preparation of a clock source | |
124 | * @clk: clock source | |
125 | * | |
126 | * This undoes a previously prepared clock. The caller must balance | |
127 | * the number of prepare and unprepare calls. | |
128 | * | |
129 | * Must not be called from within atomic context. | |
130 | */ | |
131 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
132 | void clk_unprepare(struct clk *clk); | |
133 | #else | |
134 | static inline void clk_unprepare(struct clk *clk) | |
135 | { | |
136 | might_sleep(); | |
137 | } | |
138 | #endif | |
139 | ||
140 | #ifdef CONFIG_HAVE_CLK | |
1da177e4 LT |
141 | /** |
142 | * clk_get - lookup and obtain a reference to a clock producer. | |
143 | * @dev: device for clock "consumer" | |
a58b3a4a | 144 | * @id: clock consumer ID |
1da177e4 LT |
145 | * |
146 | * Returns a struct clk corresponding to the clock producer, or | |
ea3f4eac RK |
147 | * valid IS_ERR() condition containing errno. The implementation |
148 | * uses @dev and @id to determine the clock consumer, and thereby | |
149 | * the clock producer. (IOW, @id may be identical strings, but | |
150 | * clk_get may return different clock producers depending on @dev.) | |
f47fc0ac RK |
151 | * |
152 | * Drivers must assume that the clock source is not enabled. | |
f7ad160b AR |
153 | * |
154 | * clk_get should not be called from within interrupt context. | |
1da177e4 LT |
155 | */ |
156 | struct clk *clk_get(struct device *dev, const char *id); | |
157 | ||
a8a97db9 MB |
158 | /** |
159 | * devm_clk_get - lookup and obtain a managed reference to a clock producer. | |
160 | * @dev: device for clock "consumer" | |
a58b3a4a | 161 | * @id: clock consumer ID |
a8a97db9 MB |
162 | * |
163 | * Returns a struct clk corresponding to the clock producer, or | |
164 | * valid IS_ERR() condition containing errno. The implementation | |
165 | * uses @dev and @id to determine the clock consumer, and thereby | |
166 | * the clock producer. (IOW, @id may be identical strings, but | |
167 | * clk_get may return different clock producers depending on @dev.) | |
168 | * | |
169 | * Drivers must assume that the clock source is not enabled. | |
170 | * | |
171 | * devm_clk_get should not be called from within interrupt context. | |
172 | * | |
173 | * The clock will automatically be freed when the device is unbound | |
174 | * from the bus. | |
175 | */ | |
176 | struct clk *devm_clk_get(struct device *dev, const char *id); | |
177 | ||
1da177e4 LT |
178 | /** |
179 | * clk_enable - inform the system when the clock source should be running. | |
180 | * @clk: clock source | |
181 | * | |
182 | * If the clock can not be enabled/disabled, this should return success. | |
183 | * | |
40d3e0f4 RK |
184 | * May be called from atomic contexts. |
185 | * | |
1da177e4 LT |
186 | * Returns success (0) or negative errno. |
187 | */ | |
188 | int clk_enable(struct clk *clk); | |
189 | ||
190 | /** | |
191 | * clk_disable - inform the system when the clock source is no longer required. | |
192 | * @clk: clock source | |
f47fc0ac RK |
193 | * |
194 | * Inform the system that a clock source is no longer required by | |
195 | * a driver and may be shut down. | |
196 | * | |
40d3e0f4 RK |
197 | * May be called from atomic contexts. |
198 | * | |
f47fc0ac RK |
199 | * Implementation detail: if the clock source is shared between |
200 | * multiple drivers, clk_enable() calls must be balanced by the | |
201 | * same number of clk_disable() calls for the clock source to be | |
202 | * disabled. | |
1da177e4 LT |
203 | */ |
204 | void clk_disable(struct clk *clk); | |
205 | ||
1da177e4 LT |
206 | /** |
207 | * clk_get_rate - obtain the current clock rate (in Hz) for a clock source. | |
208 | * This is only valid once the clock source has been enabled. | |
209 | * @clk: clock source | |
210 | */ | |
211 | unsigned long clk_get_rate(struct clk *clk); | |
212 | ||
213 | /** | |
214 | * clk_put - "free" the clock source | |
215 | * @clk: clock source | |
f47fc0ac RK |
216 | * |
217 | * Note: drivers must ensure that all clk_enable calls made on this | |
218 | * clock source are balanced by clk_disable calls prior to calling | |
219 | * this function. | |
f7ad160b AR |
220 | * |
221 | * clk_put should not be called from within interrupt context. | |
1da177e4 LT |
222 | */ |
223 | void clk_put(struct clk *clk); | |
224 | ||
a8a97db9 MB |
225 | /** |
226 | * devm_clk_put - "free" a managed clock source | |
227 | * @dev: device used to acuqire the clock | |
228 | * @clk: clock source acquired with devm_clk_get() | |
229 | * | |
230 | * Note: drivers must ensure that all clk_enable calls made on this | |
231 | * clock source are balanced by clk_disable calls prior to calling | |
232 | * this function. | |
233 | * | |
234 | * clk_put should not be called from within interrupt context. | |
235 | */ | |
236 | void devm_clk_put(struct device *dev, struct clk *clk); | |
1da177e4 LT |
237 | |
238 | /* | |
239 | * The remaining APIs are optional for machine class support. | |
240 | */ | |
241 | ||
242 | ||
243 | /** | |
244 | * clk_round_rate - adjust a rate to the exact rate a clock can provide | |
245 | * @clk: clock source | |
246 | * @rate: desired clock rate in Hz | |
247 | * | |
248 | * Returns rounded clock rate in Hz, or negative errno. | |
249 | */ | |
250 | long clk_round_rate(struct clk *clk, unsigned long rate); | |
8b7730dd | 251 | |
1da177e4 LT |
252 | /** |
253 | * clk_set_rate - set the clock rate for a clock source | |
254 | * @clk: clock source | |
255 | * @rate: desired clock rate in Hz | |
256 | * | |
257 | * Returns success (0) or negative errno. | |
258 | */ | |
259 | int clk_set_rate(struct clk *clk, unsigned long rate); | |
8b7730dd | 260 | |
1da177e4 LT |
261 | /** |
262 | * clk_set_parent - set the parent clock source for this clock | |
263 | * @clk: clock source | |
264 | * @parent: parent clock source | |
265 | * | |
266 | * Returns success (0) or negative errno. | |
267 | */ | |
268 | int clk_set_parent(struct clk *clk, struct clk *parent); | |
269 | ||
270 | /** | |
271 | * clk_get_parent - get the parent clock source for this clock | |
272 | * @clk: clock source | |
273 | * | |
274 | * Returns struct clk corresponding to parent clock source, or | |
275 | * valid IS_ERR() condition containing errno. | |
276 | */ | |
277 | struct clk *clk_get_parent(struct clk *clk); | |
278 | ||
05fd8e73 SH |
279 | /** |
280 | * clk_get_sys - get a clock based upon the device name | |
281 | * @dev_id: device name | |
282 | * @con_id: connection ID | |
283 | * | |
284 | * Returns a struct clk corresponding to the clock producer, or | |
285 | * valid IS_ERR() condition containing errno. The implementation | |
286 | * uses @dev_id and @con_id to determine the clock consumer, and | |
287 | * thereby the clock producer. In contrast to clk_get() this function | |
288 | * takes the device name instead of the device itself for identification. | |
289 | * | |
290 | * Drivers must assume that the clock source is not enabled. | |
291 | * | |
292 | * clk_get_sys should not be called from within interrupt context. | |
293 | */ | |
294 | struct clk *clk_get_sys(const char *dev_id, const char *con_id); | |
295 | ||
93abe8e4 VK |
296 | #else /* !CONFIG_HAVE_CLK */ |
297 | ||
298 | static inline struct clk *clk_get(struct device *dev, const char *id) | |
299 | { | |
300 | return NULL; | |
301 | } | |
302 | ||
303 | static inline struct clk *devm_clk_get(struct device *dev, const char *id) | |
304 | { | |
305 | return NULL; | |
306 | } | |
307 | ||
308 | static inline void clk_put(struct clk *clk) {} | |
309 | ||
310 | static inline void devm_clk_put(struct device *dev, struct clk *clk) {} | |
311 | ||
312 | static inline int clk_enable(struct clk *clk) | |
313 | { | |
314 | return 0; | |
315 | } | |
316 | ||
317 | static inline void clk_disable(struct clk *clk) {} | |
318 | ||
319 | static inline unsigned long clk_get_rate(struct clk *clk) | |
320 | { | |
321 | return 0; | |
322 | } | |
323 | ||
324 | static inline int clk_set_rate(struct clk *clk, unsigned long rate) | |
325 | { | |
326 | return 0; | |
327 | } | |
328 | ||
329 | static inline long clk_round_rate(struct clk *clk, unsigned long rate) | |
330 | { | |
331 | return 0; | |
332 | } | |
333 | ||
334 | static inline int clk_set_parent(struct clk *clk, struct clk *parent) | |
335 | { | |
336 | return 0; | |
337 | } | |
338 | ||
339 | static inline struct clk *clk_get_parent(struct clk *clk) | |
340 | { | |
341 | return NULL; | |
342 | } | |
343 | ||
344 | #endif | |
345 | ||
346 | /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */ | |
347 | static inline int clk_prepare_enable(struct clk *clk) | |
348 | { | |
349 | int ret; | |
350 | ||
351 | ret = clk_prepare(clk); | |
352 | if (ret) | |
353 | return ret; | |
354 | ret = clk_enable(clk); | |
355 | if (ret) | |
356 | clk_unprepare(clk); | |
357 | ||
358 | return ret; | |
359 | } | |
360 | ||
361 | /* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */ | |
362 | static inline void clk_disable_unprepare(struct clk *clk) | |
363 | { | |
364 | clk_disable(clk); | |
365 | clk_unprepare(clk); | |
366 | } | |
367 | ||
c0683039 TL |
368 | /** |
369 | * clk_add_alias - add a new clock alias | |
370 | * @alias: name for clock alias | |
371 | * @alias_dev_name: device name | |
372 | * @id: platform specific clock name | |
373 | * @dev: device | |
374 | * | |
375 | * Allows using generic clock names for drivers by adding a new alias. | |
376 | * Assumes clkdev, see clkdev.h for more info. | |
377 | */ | |
378 | int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, | |
379 | struct device *dev); | |
380 | ||
766e6a4e GL |
381 | struct device_node; |
382 | struct of_phandle_args; | |
383 | ||
137f8a72 | 384 | #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) |
766e6a4e GL |
385 | struct clk *of_clk_get(struct device_node *np, int index); |
386 | struct clk *of_clk_get_by_name(struct device_node *np, const char *name); | |
387 | struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec); | |
388 | #else | |
389 | static inline struct clk *of_clk_get(struct device_node *np, int index) | |
390 | { | |
9f1612d3 | 391 | return ERR_PTR(-ENOENT); |
766e6a4e GL |
392 | } |
393 | static inline struct clk *of_clk_get_by_name(struct device_node *np, | |
394 | const char *name) | |
395 | { | |
9f1612d3 | 396 | return ERR_PTR(-ENOENT); |
766e6a4e GL |
397 | } |
398 | #endif | |
399 | ||
1da177e4 | 400 | #endif |