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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 | ||
86bcfa2e MT |
81 | /** |
82 | * clk_notifier_register: register a clock rate-change notifier callback | |
83 | * @clk: clock whose rate we are interested in | |
84 | * @nb: notifier block with callback function pointer | |
85 | * | |
86 | * ProTip: debugging across notifier chains can be frustrating. Make sure that | |
87 | * your notifier callback function prints a nice big warning in case of | |
88 | * failure. | |
89 | */ | |
b2476490 MT |
90 | int clk_notifier_register(struct clk *clk, struct notifier_block *nb); |
91 | ||
86bcfa2e MT |
92 | /** |
93 | * clk_notifier_unregister: unregister a clock rate-change notifier callback | |
94 | * @clk: clock whose rate we are no longer interested in | |
95 | * @nb: notifier block which will be unregistered | |
96 | */ | |
b2476490 MT |
97 | int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb); |
98 | ||
5279fc40 BB |
99 | /** |
100 | * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion) | |
101 | * for a clock source. | |
102 | * @clk: clock source | |
103 | * | |
104 | * This gets the clock source accuracy expressed in ppb. | |
105 | * A perfect clock returns 0. | |
106 | */ | |
107 | long clk_get_accuracy(struct clk *clk); | |
108 | ||
e59c5371 MT |
109 | /** |
110 | * clk_set_phase - adjust the phase shift of a clock signal | |
111 | * @clk: clock signal source | |
112 | * @degrees: number of degrees the signal is shifted | |
113 | * | |
114 | * Shifts the phase of a clock signal by the specified degrees. Returns 0 on | |
115 | * success, -EERROR otherwise. | |
116 | */ | |
117 | int clk_set_phase(struct clk *clk, int degrees); | |
118 | ||
119 | /** | |
120 | * clk_get_phase - return the phase shift of a clock signal | |
121 | * @clk: clock signal source | |
122 | * | |
123 | * Returns the phase shift of a clock node in degrees, otherwise returns | |
124 | * -EERROR. | |
125 | */ | |
126 | int clk_get_phase(struct clk *clk); | |
127 | ||
5279fc40 BB |
128 | #else |
129 | ||
130 | static inline long clk_get_accuracy(struct clk *clk) | |
131 | { | |
132 | return -ENOTSUPP; | |
133 | } | |
134 | ||
e59c5371 MT |
135 | static inline long clk_set_phase(struct clk *clk, int phase) |
136 | { | |
137 | return -ENOTSUPP; | |
138 | } | |
139 | ||
140 | static inline long clk_get_phase(struct clk *clk) | |
141 | { | |
142 | return -ENOTSUPP; | |
143 | } | |
144 | ||
7e87aed9 | 145 | #endif |
1da177e4 | 146 | |
93abe8e4 VK |
147 | /** |
148 | * clk_prepare - prepare a clock source | |
149 | * @clk: clock source | |
150 | * | |
151 | * This prepares the clock source for use. | |
152 | * | |
153 | * Must not be called from within atomic context. | |
154 | */ | |
155 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
156 | int clk_prepare(struct clk *clk); | |
157 | #else | |
158 | static inline int clk_prepare(struct clk *clk) | |
159 | { | |
160 | might_sleep(); | |
161 | return 0; | |
162 | } | |
163 | #endif | |
164 | ||
165 | /** | |
166 | * clk_unprepare - undo preparation of a clock source | |
167 | * @clk: clock source | |
168 | * | |
169 | * This undoes a previously prepared clock. The caller must balance | |
170 | * the number of prepare and unprepare calls. | |
171 | * | |
172 | * Must not be called from within atomic context. | |
173 | */ | |
174 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
175 | void clk_unprepare(struct clk *clk); | |
176 | #else | |
177 | static inline void clk_unprepare(struct clk *clk) | |
178 | { | |
179 | might_sleep(); | |
180 | } | |
181 | #endif | |
182 | ||
183 | #ifdef CONFIG_HAVE_CLK | |
1da177e4 LT |
184 | /** |
185 | * clk_get - lookup and obtain a reference to a clock producer. | |
186 | * @dev: device for clock "consumer" | |
a58b3a4a | 187 | * @id: clock consumer ID |
1da177e4 LT |
188 | * |
189 | * Returns a struct clk corresponding to the clock producer, or | |
ea3f4eac RK |
190 | * valid IS_ERR() condition containing errno. The implementation |
191 | * uses @dev and @id to determine the clock consumer, and thereby | |
192 | * the clock producer. (IOW, @id may be identical strings, but | |
193 | * clk_get may return different clock producers depending on @dev.) | |
f47fc0ac RK |
194 | * |
195 | * Drivers must assume that the clock source is not enabled. | |
f7ad160b AR |
196 | * |
197 | * clk_get should not be called from within interrupt context. | |
1da177e4 LT |
198 | */ |
199 | struct clk *clk_get(struct device *dev, const char *id); | |
200 | ||
a8a97db9 MB |
201 | /** |
202 | * devm_clk_get - lookup and obtain a managed reference to a clock producer. | |
203 | * @dev: device for clock "consumer" | |
a58b3a4a | 204 | * @id: clock consumer ID |
a8a97db9 MB |
205 | * |
206 | * Returns a struct clk corresponding to the clock producer, or | |
207 | * valid IS_ERR() condition containing errno. The implementation | |
208 | * uses @dev and @id to determine the clock consumer, and thereby | |
209 | * the clock producer. (IOW, @id may be identical strings, but | |
210 | * clk_get may return different clock producers depending on @dev.) | |
211 | * | |
212 | * Drivers must assume that the clock source is not enabled. | |
213 | * | |
214 | * devm_clk_get should not be called from within interrupt context. | |
215 | * | |
216 | * The clock will automatically be freed when the device is unbound | |
217 | * from the bus. | |
218 | */ | |
219 | struct clk *devm_clk_get(struct device *dev, const char *id); | |
220 | ||
1da177e4 LT |
221 | /** |
222 | * clk_enable - inform the system when the clock source should be running. | |
223 | * @clk: clock source | |
224 | * | |
225 | * If the clock can not be enabled/disabled, this should return success. | |
226 | * | |
40d3e0f4 RK |
227 | * May be called from atomic contexts. |
228 | * | |
1da177e4 LT |
229 | * Returns success (0) or negative errno. |
230 | */ | |
231 | int clk_enable(struct clk *clk); | |
232 | ||
233 | /** | |
234 | * clk_disable - inform the system when the clock source is no longer required. | |
235 | * @clk: clock source | |
f47fc0ac RK |
236 | * |
237 | * Inform the system that a clock source is no longer required by | |
238 | * a driver and may be shut down. | |
239 | * | |
40d3e0f4 RK |
240 | * May be called from atomic contexts. |
241 | * | |
f47fc0ac RK |
242 | * Implementation detail: if the clock source is shared between |
243 | * multiple drivers, clk_enable() calls must be balanced by the | |
244 | * same number of clk_disable() calls for the clock source to be | |
245 | * disabled. | |
1da177e4 LT |
246 | */ |
247 | void clk_disable(struct clk *clk); | |
248 | ||
1da177e4 LT |
249 | /** |
250 | * clk_get_rate - obtain the current clock rate (in Hz) for a clock source. | |
251 | * This is only valid once the clock source has been enabled. | |
252 | * @clk: clock source | |
253 | */ | |
254 | unsigned long clk_get_rate(struct clk *clk); | |
255 | ||
256 | /** | |
257 | * clk_put - "free" the clock source | |
258 | * @clk: clock source | |
f47fc0ac RK |
259 | * |
260 | * Note: drivers must ensure that all clk_enable calls made on this | |
261 | * clock source are balanced by clk_disable calls prior to calling | |
262 | * this function. | |
f7ad160b AR |
263 | * |
264 | * clk_put should not be called from within interrupt context. | |
1da177e4 LT |
265 | */ |
266 | void clk_put(struct clk *clk); | |
267 | ||
a8a97db9 MB |
268 | /** |
269 | * devm_clk_put - "free" a managed clock source | |
da3dae54 | 270 | * @dev: device used to acquire the clock |
a8a97db9 MB |
271 | * @clk: clock source acquired with devm_clk_get() |
272 | * | |
273 | * Note: drivers must ensure that all clk_enable calls made on this | |
274 | * clock source are balanced by clk_disable calls prior to calling | |
275 | * this function. | |
276 | * | |
277 | * clk_put should not be called from within interrupt context. | |
278 | */ | |
279 | void devm_clk_put(struct device *dev, struct clk *clk); | |
1da177e4 LT |
280 | |
281 | /* | |
282 | * The remaining APIs are optional for machine class support. | |
283 | */ | |
284 | ||
285 | ||
286 | /** | |
287 | * clk_round_rate - adjust a rate to the exact rate a clock can provide | |
288 | * @clk: clock source | |
289 | * @rate: desired clock rate in Hz | |
290 | * | |
291 | * Returns rounded clock rate in Hz, or negative errno. | |
292 | */ | |
293 | long clk_round_rate(struct clk *clk, unsigned long rate); | |
8b7730dd | 294 | |
1da177e4 LT |
295 | /** |
296 | * clk_set_rate - set the clock rate for a clock source | |
297 | * @clk: clock source | |
298 | * @rate: desired clock rate in Hz | |
299 | * | |
300 | * Returns success (0) or negative errno. | |
301 | */ | |
302 | int clk_set_rate(struct clk *clk, unsigned long rate); | |
8b7730dd | 303 | |
1da177e4 LT |
304 | /** |
305 | * clk_set_parent - set the parent clock source for this clock | |
306 | * @clk: clock source | |
307 | * @parent: parent clock source | |
308 | * | |
309 | * Returns success (0) or negative errno. | |
310 | */ | |
311 | int clk_set_parent(struct clk *clk, struct clk *parent); | |
312 | ||
313 | /** | |
314 | * clk_get_parent - get the parent clock source for this clock | |
315 | * @clk: clock source | |
316 | * | |
317 | * Returns struct clk corresponding to parent clock source, or | |
318 | * valid IS_ERR() condition containing errno. | |
319 | */ | |
320 | struct clk *clk_get_parent(struct clk *clk); | |
321 | ||
05fd8e73 SH |
322 | /** |
323 | * clk_get_sys - get a clock based upon the device name | |
324 | * @dev_id: device name | |
325 | * @con_id: connection ID | |
326 | * | |
327 | * Returns a struct clk corresponding to the clock producer, or | |
328 | * valid IS_ERR() condition containing errno. The implementation | |
329 | * uses @dev_id and @con_id to determine the clock consumer, and | |
330 | * thereby the clock producer. In contrast to clk_get() this function | |
331 | * takes the device name instead of the device itself for identification. | |
332 | * | |
333 | * Drivers must assume that the clock source is not enabled. | |
334 | * | |
335 | * clk_get_sys should not be called from within interrupt context. | |
336 | */ | |
337 | struct clk *clk_get_sys(const char *dev_id, const char *con_id); | |
338 | ||
93abe8e4 VK |
339 | #else /* !CONFIG_HAVE_CLK */ |
340 | ||
341 | static inline struct clk *clk_get(struct device *dev, const char *id) | |
342 | { | |
343 | return NULL; | |
344 | } | |
345 | ||
346 | static inline struct clk *devm_clk_get(struct device *dev, const char *id) | |
347 | { | |
348 | return NULL; | |
349 | } | |
350 | ||
351 | static inline void clk_put(struct clk *clk) {} | |
352 | ||
353 | static inline void devm_clk_put(struct device *dev, struct clk *clk) {} | |
354 | ||
355 | static inline int clk_enable(struct clk *clk) | |
356 | { | |
357 | return 0; | |
358 | } | |
359 | ||
360 | static inline void clk_disable(struct clk *clk) {} | |
361 | ||
362 | static inline unsigned long clk_get_rate(struct clk *clk) | |
363 | { | |
364 | return 0; | |
365 | } | |
366 | ||
367 | static inline int clk_set_rate(struct clk *clk, unsigned long rate) | |
368 | { | |
369 | return 0; | |
370 | } | |
371 | ||
372 | static inline long clk_round_rate(struct clk *clk, unsigned long rate) | |
373 | { | |
374 | return 0; | |
375 | } | |
376 | ||
377 | static inline int clk_set_parent(struct clk *clk, struct clk *parent) | |
378 | { | |
379 | return 0; | |
380 | } | |
381 | ||
382 | static inline struct clk *clk_get_parent(struct clk *clk) | |
383 | { | |
384 | return NULL; | |
385 | } | |
386 | ||
387 | #endif | |
388 | ||
389 | /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */ | |
390 | static inline int clk_prepare_enable(struct clk *clk) | |
391 | { | |
392 | int ret; | |
393 | ||
394 | ret = clk_prepare(clk); | |
395 | if (ret) | |
396 | return ret; | |
397 | ret = clk_enable(clk); | |
398 | if (ret) | |
399 | clk_unprepare(clk); | |
400 | ||
401 | return ret; | |
402 | } | |
403 | ||
404 | /* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */ | |
405 | static inline void clk_disable_unprepare(struct clk *clk) | |
406 | { | |
407 | clk_disable(clk); | |
408 | clk_unprepare(clk); | |
409 | } | |
410 | ||
c0683039 TL |
411 | /** |
412 | * clk_add_alias - add a new clock alias | |
413 | * @alias: name for clock alias | |
414 | * @alias_dev_name: device name | |
415 | * @id: platform specific clock name | |
416 | * @dev: device | |
417 | * | |
418 | * Allows using generic clock names for drivers by adding a new alias. | |
419 | * Assumes clkdev, see clkdev.h for more info. | |
420 | */ | |
421 | int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, | |
422 | struct device *dev); | |
423 | ||
766e6a4e GL |
424 | struct device_node; |
425 | struct of_phandle_args; | |
426 | ||
137f8a72 | 427 | #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) |
766e6a4e GL |
428 | struct clk *of_clk_get(struct device_node *np, int index); |
429 | struct clk *of_clk_get_by_name(struct device_node *np, const char *name); | |
430 | struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec); | |
431 | #else | |
432 | static inline struct clk *of_clk_get(struct device_node *np, int index) | |
433 | { | |
9f1612d3 | 434 | return ERR_PTR(-ENOENT); |
766e6a4e GL |
435 | } |
436 | static inline struct clk *of_clk_get_by_name(struct device_node *np, | |
437 | const char *name) | |
438 | { | |
9f1612d3 | 439 | return ERR_PTR(-ENOENT); |
766e6a4e GL |
440 | } |
441 | #endif | |
442 | ||
1da177e4 | 443 | #endif |