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