Merge tag 'rpmsg-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/rpmsg
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / linux / clk.h
1 /*
2 * linux/include/linux/clk.h
3 *
4 * Copyright (C) 2004 ARM Limited.
5 * Written by Deep Blue Solutions Limited.
6 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
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 */
12 #ifndef __LINUX_CLK_H
13 #define __LINUX_CLK_H
14
15 #include <linux/err.h>
16 #include <linux/kernel.h>
17 #include <linux/notifier.h>
18
19 struct device;
20
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
31 * rate change. Callbacks may either return NOTIFY_DONE, NOTIFY_OK,
32 * NOTIFY_STOP or NOTIFY_BAD.
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
37 * always return NOTIFY_DONE or NOTIFY_OK.
38 *
39 * POST_RATE_CHANGE - called after the clk rate change has successfully
40 * completed. Callbacks must always return NOTIFY_DONE or NOTIFY_OK.
41 *
42 */
43 #define PRE_RATE_CHANGE BIT(0)
44 #define POST_RATE_CHANGE BIT(1)
45 #define ABORT_RATE_CHANGE BIT(2)
46
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 };
63
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).
74 */
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
85 #endif
86
87 /**
88 * clk_prepare - prepare a clock source
89 * @clk: clock source
90 *
91 * This prepares the clock source for use.
92 *
93 * Must not be called from within atomic context.
94 */
95 #ifdef CONFIG_HAVE_CLK_PREPARE
96 int clk_prepare(struct clk *clk);
97 #else
98 static inline int clk_prepare(struct clk *clk)
99 {
100 might_sleep();
101 return 0;
102 }
103 #endif
104
105 /**
106 * clk_unprepare - undo preparation of a clock source
107 * @clk: clock source
108 *
109 * This undoes a previously prepared clock. The caller must balance
110 * the number of prepare and unprepare calls.
111 *
112 * Must not be called from within atomic context.
113 */
114 #ifdef CONFIG_HAVE_CLK_PREPARE
115 void clk_unprepare(struct clk *clk);
116 #else
117 static inline void clk_unprepare(struct clk *clk)
118 {
119 might_sleep();
120 }
121 #endif
122
123 #ifdef CONFIG_HAVE_CLK
124 /**
125 * clk_get - lookup and obtain a reference to a clock producer.
126 * @dev: device for clock "consumer"
127 * @id: clock consumer ID
128 *
129 * Returns a struct clk corresponding to the clock producer, or
130 * valid IS_ERR() condition containing errno. The implementation
131 * uses @dev and @id to determine the clock consumer, and thereby
132 * the clock producer. (IOW, @id may be identical strings, but
133 * clk_get may return different clock producers depending on @dev.)
134 *
135 * Drivers must assume that the clock source is not enabled.
136 *
137 * clk_get should not be called from within interrupt context.
138 */
139 struct clk *clk_get(struct device *dev, const char *id);
140
141 /**
142 * devm_clk_get - lookup and obtain a managed reference to a clock producer.
143 * @dev: device for clock "consumer"
144 * @id: clock consumer ID
145 *
146 * Returns a struct clk corresponding to the clock producer, or
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.)
151 *
152 * Drivers must assume that the clock source is not enabled.
153 *
154 * devm_clk_get should not be called from within interrupt context.
155 *
156 * The clock will automatically be freed when the device is unbound
157 * from the bus.
158 */
159 struct clk *devm_clk_get(struct device *dev, const char *id);
160
161 /**
162 * clk_enable - inform the system when the clock source should be running.
163 * @clk: clock source
164 *
165 * If the clock can not be enabled/disabled, this should return success.
166 *
167 * May be called from atomic contexts.
168 *
169 * Returns success (0) or negative errno.
170 */
171 int clk_enable(struct clk *clk);
172
173 /**
174 * clk_disable - inform the system when the clock source is no longer required.
175 * @clk: clock source
176 *
177 * Inform the system that a clock source is no longer required by
178 * a driver and may be shut down.
179 *
180 * May be called from atomic contexts.
181 *
182 * Implementation detail: if the clock source is shared between
183 * multiple drivers, clk_enable() calls must be balanced by the
184 * same number of clk_disable() calls for the clock source to be
185 * disabled.
186 */
187 void clk_disable(struct clk *clk);
188
189 /**
190 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
191 * This is only valid once the clock source has been enabled.
192 * @clk: clock source
193 */
194 unsigned long clk_get_rate(struct clk *clk);
195
196 /**
197 * clk_put - "free" the clock source
198 * @clk: clock source
199 *
200 * Note: drivers must ensure that all clk_enable calls made on this
201 * clock source are balanced by clk_disable calls prior to calling
202 * this function.
203 *
204 * clk_put should not be called from within interrupt context.
205 */
206 void clk_put(struct clk *clk);
207
208 /**
209 * devm_clk_put - "free" a managed clock source
210 * @dev: device used to acuqire the clock
211 * @clk: clock source acquired with devm_clk_get()
212 *
213 * Note: drivers must ensure that all clk_enable calls made on this
214 * clock source are balanced by clk_disable calls prior to calling
215 * this function.
216 *
217 * clk_put should not be called from within interrupt context.
218 */
219 void devm_clk_put(struct device *dev, struct clk *clk);
220
221 /*
222 * The remaining APIs are optional for machine class support.
223 */
224
225
226 /**
227 * clk_round_rate - adjust a rate to the exact rate a clock can provide
228 * @clk: clock source
229 * @rate: desired clock rate in Hz
230 *
231 * Returns rounded clock rate in Hz, or negative errno.
232 */
233 long clk_round_rate(struct clk *clk, unsigned long rate);
234
235 /**
236 * clk_set_rate - set the clock rate for a clock source
237 * @clk: clock source
238 * @rate: desired clock rate in Hz
239 *
240 * Returns success (0) or negative errno.
241 */
242 int clk_set_rate(struct clk *clk, unsigned long rate);
243
244 /**
245 * clk_set_parent - set the parent clock source for this clock
246 * @clk: clock source
247 * @parent: parent clock source
248 *
249 * Returns success (0) or negative errno.
250 */
251 int clk_set_parent(struct clk *clk, struct clk *parent);
252
253 /**
254 * clk_get_parent - get the parent clock source for this clock
255 * @clk: clock source
256 *
257 * Returns struct clk corresponding to parent clock source, or
258 * valid IS_ERR() condition containing errno.
259 */
260 struct clk *clk_get_parent(struct clk *clk);
261
262 /**
263 * clk_get_sys - get a clock based upon the device name
264 * @dev_id: device name
265 * @con_id: connection ID
266 *
267 * Returns a struct clk corresponding to the clock producer, or
268 * valid IS_ERR() condition containing errno. The implementation
269 * uses @dev_id and @con_id to determine the clock consumer, and
270 * thereby the clock producer. In contrast to clk_get() this function
271 * takes the device name instead of the device itself for identification.
272 *
273 * Drivers must assume that the clock source is not enabled.
274 *
275 * clk_get_sys should not be called from within interrupt context.
276 */
277 struct clk *clk_get_sys(const char *dev_id, const char *con_id);
278
279 #else /* !CONFIG_HAVE_CLK */
280
281 static inline struct clk *clk_get(struct device *dev, const char *id)
282 {
283 return NULL;
284 }
285
286 static inline struct clk *devm_clk_get(struct device *dev, const char *id)
287 {
288 return NULL;
289 }
290
291 static inline void clk_put(struct clk *clk) {}
292
293 static inline void devm_clk_put(struct device *dev, struct clk *clk) {}
294
295 static inline int clk_enable(struct clk *clk)
296 {
297 return 0;
298 }
299
300 static inline void clk_disable(struct clk *clk) {}
301
302 static inline unsigned long clk_get_rate(struct clk *clk)
303 {
304 return 0;
305 }
306
307 static inline int clk_set_rate(struct clk *clk, unsigned long rate)
308 {
309 return 0;
310 }
311
312 static inline long clk_round_rate(struct clk *clk, unsigned long rate)
313 {
314 return 0;
315 }
316
317 static inline int clk_set_parent(struct clk *clk, struct clk *parent)
318 {
319 return 0;
320 }
321
322 static inline struct clk *clk_get_parent(struct clk *clk)
323 {
324 return NULL;
325 }
326
327 #endif
328
329 /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
330 static inline int clk_prepare_enable(struct clk *clk)
331 {
332 int ret;
333
334 ret = clk_prepare(clk);
335 if (ret)
336 return ret;
337 ret = clk_enable(clk);
338 if (ret)
339 clk_unprepare(clk);
340
341 return ret;
342 }
343
344 /* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
345 static inline void clk_disable_unprepare(struct clk *clk)
346 {
347 clk_disable(clk);
348 clk_unprepare(clk);
349 }
350
351 /**
352 * clk_add_alias - add a new clock alias
353 * @alias: name for clock alias
354 * @alias_dev_name: device name
355 * @id: platform specific clock name
356 * @dev: device
357 *
358 * Allows using generic clock names for drivers by adding a new alias.
359 * Assumes clkdev, see clkdev.h for more info.
360 */
361 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
362 struct device *dev);
363
364 struct device_node;
365 struct of_phandle_args;
366
367 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
368 struct clk *of_clk_get(struct device_node *np, int index);
369 struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
370 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
371 #else
372 static inline struct clk *of_clk_get(struct device_node *np, int index)
373 {
374 return ERR_PTR(-ENOENT);
375 }
376 static inline struct clk *of_clk_get_by_name(struct device_node *np,
377 const char *name)
378 {
379 return ERR_PTR(-ENOENT);
380 }
381 #endif
382
383 #endif