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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 | ||
a8a97db9 MB |
103 | /** |
104 | * devm_clk_get - lookup and obtain a managed reference to a clock producer. | |
105 | * @dev: device for clock "consumer" | |
106 | * @id: clock comsumer ID | |
107 | * | |
108 | * Returns a struct clk corresponding to the clock producer, or | |
109 | * valid IS_ERR() condition containing errno. The implementation | |
110 | * uses @dev and @id to determine the clock consumer, and thereby | |
111 | * the clock producer. (IOW, @id may be identical strings, but | |
112 | * clk_get may return different clock producers depending on @dev.) | |
113 | * | |
114 | * Drivers must assume that the clock source is not enabled. | |
115 | * | |
116 | * devm_clk_get should not be called from within interrupt context. | |
117 | * | |
118 | * The clock will automatically be freed when the device is unbound | |
119 | * from the bus. | |
120 | */ | |
121 | struct clk *devm_clk_get(struct device *dev, const char *id); | |
122 | ||
40d3e0f4 RK |
123 | /** |
124 | * clk_prepare - prepare a clock source | |
125 | * @clk: clock source | |
126 | * | |
127 | * This prepares the clock source for use. | |
128 | * | |
129 | * Must not be called from within atomic context. | |
130 | */ | |
131 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
132 | int clk_prepare(struct clk *clk); | |
133 | #else | |
134 | static inline int clk_prepare(struct clk *clk) | |
135 | { | |
136 | might_sleep(); | |
137 | return 0; | |
138 | } | |
139 | #endif | |
140 | ||
1da177e4 LT |
141 | /** |
142 | * clk_enable - inform the system when the clock source should be running. | |
143 | * @clk: clock source | |
144 | * | |
145 | * If the clock can not be enabled/disabled, this should return success. | |
146 | * | |
40d3e0f4 RK |
147 | * May be called from atomic contexts. |
148 | * | |
1da177e4 LT |
149 | * Returns success (0) or negative errno. |
150 | */ | |
151 | int clk_enable(struct clk *clk); | |
152 | ||
153 | /** | |
154 | * clk_disable - inform the system when the clock source is no longer required. | |
155 | * @clk: clock source | |
f47fc0ac RK |
156 | * |
157 | * Inform the system that a clock source is no longer required by | |
158 | * a driver and may be shut down. | |
159 | * | |
40d3e0f4 RK |
160 | * May be called from atomic contexts. |
161 | * | |
f47fc0ac RK |
162 | * Implementation detail: if the clock source is shared between |
163 | * multiple drivers, clk_enable() calls must be balanced by the | |
164 | * same number of clk_disable() calls for the clock source to be | |
165 | * disabled. | |
1da177e4 LT |
166 | */ |
167 | void clk_disable(struct clk *clk); | |
168 | ||
40d3e0f4 RK |
169 | |
170 | /** | |
171 | * clk_unprepare - undo preparation of a clock source | |
172 | * @clk: clock source | |
173 | * | |
174 | * This undoes a previously prepared clock. The caller must balance | |
175 | * the number of prepare and unprepare calls. | |
176 | * | |
177 | * Must not be called from within atomic context. | |
178 | */ | |
179 | #ifdef CONFIG_HAVE_CLK_PREPARE | |
180 | void clk_unprepare(struct clk *clk); | |
181 | #else | |
182 | static inline void clk_unprepare(struct clk *clk) | |
183 | { | |
184 | might_sleep(); | |
185 | } | |
186 | #endif | |
187 | ||
42c5d52f RZ |
188 | /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */ |
189 | static inline int clk_prepare_enable(struct clk *clk) | |
190 | { | |
191 | int ret; | |
192 | ||
193 | ret = clk_prepare(clk); | |
194 | if (ret) | |
195 | return ret; | |
196 | ret = clk_enable(clk); | |
197 | if (ret) | |
198 | clk_unprepare(clk); | |
199 | ||
200 | return ret; | |
201 | } | |
202 | ||
203 | /* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */ | |
204 | static inline void clk_disable_unprepare(struct clk *clk) | |
205 | { | |
206 | clk_disable(clk); | |
207 | clk_unprepare(clk); | |
208 | } | |
209 | ||
1da177e4 LT |
210 | /** |
211 | * clk_get_rate - obtain the current clock rate (in Hz) for a clock source. | |
212 | * This is only valid once the clock source has been enabled. | |
213 | * @clk: clock source | |
214 | */ | |
215 | unsigned long clk_get_rate(struct clk *clk); | |
216 | ||
217 | /** | |
218 | * clk_put - "free" the clock source | |
219 | * @clk: clock source | |
f47fc0ac RK |
220 | * |
221 | * Note: drivers must ensure that all clk_enable calls made on this | |
222 | * clock source are balanced by clk_disable calls prior to calling | |
223 | * this function. | |
f7ad160b AR |
224 | * |
225 | * clk_put should not be called from within interrupt context. | |
1da177e4 LT |
226 | */ |
227 | void clk_put(struct clk *clk); | |
228 | ||
a8a97db9 MB |
229 | /** |
230 | * devm_clk_put - "free" a managed clock source | |
231 | * @dev: device used to acuqire the clock | |
232 | * @clk: clock source acquired with devm_clk_get() | |
233 | * | |
234 | * Note: drivers must ensure that all clk_enable calls made on this | |
235 | * clock source are balanced by clk_disable calls prior to calling | |
236 | * this function. | |
237 | * | |
238 | * clk_put should not be called from within interrupt context. | |
239 | */ | |
240 | void devm_clk_put(struct device *dev, struct clk *clk); | |
1da177e4 LT |
241 | |
242 | /* | |
243 | * The remaining APIs are optional for machine class support. | |
244 | */ | |
245 | ||
246 | ||
247 | /** | |
248 | * clk_round_rate - adjust a rate to the exact rate a clock can provide | |
249 | * @clk: clock source | |
250 | * @rate: desired clock rate in Hz | |
251 | * | |
252 | * Returns rounded clock rate in Hz, or negative errno. | |
253 | */ | |
254 | long clk_round_rate(struct clk *clk, unsigned long rate); | |
8b7730dd | 255 | |
1da177e4 LT |
256 | /** |
257 | * clk_set_rate - set the clock rate for a clock source | |
258 | * @clk: clock source | |
259 | * @rate: desired clock rate in Hz | |
260 | * | |
261 | * Returns success (0) or negative errno. | |
262 | */ | |
263 | int clk_set_rate(struct clk *clk, unsigned long rate); | |
8b7730dd | 264 | |
1da177e4 LT |
265 | /** |
266 | * clk_set_parent - set the parent clock source for this clock | |
267 | * @clk: clock source | |
268 | * @parent: parent clock source | |
269 | * | |
270 | * Returns success (0) or negative errno. | |
271 | */ | |
272 | int clk_set_parent(struct clk *clk, struct clk *parent); | |
273 | ||
274 | /** | |
275 | * clk_get_parent - get the parent clock source for this clock | |
276 | * @clk: clock source | |
277 | * | |
278 | * Returns struct clk corresponding to parent clock source, or | |
279 | * valid IS_ERR() condition containing errno. | |
280 | */ | |
281 | struct clk *clk_get_parent(struct clk *clk); | |
282 | ||
05fd8e73 SH |
283 | /** |
284 | * clk_get_sys - get a clock based upon the device name | |
285 | * @dev_id: device name | |
286 | * @con_id: connection ID | |
287 | * | |
288 | * Returns a struct clk corresponding to the clock producer, or | |
289 | * valid IS_ERR() condition containing errno. The implementation | |
290 | * uses @dev_id and @con_id to determine the clock consumer, and | |
291 | * thereby the clock producer. In contrast to clk_get() this function | |
292 | * takes the device name instead of the device itself for identification. | |
293 | * | |
294 | * Drivers must assume that the clock source is not enabled. | |
295 | * | |
296 | * clk_get_sys should not be called from within interrupt context. | |
297 | */ | |
298 | struct clk *clk_get_sys(const char *dev_id, const char *con_id); | |
299 | ||
c0683039 TL |
300 | /** |
301 | * clk_add_alias - add a new clock alias | |
302 | * @alias: name for clock alias | |
303 | * @alias_dev_name: device name | |
304 | * @id: platform specific clock name | |
305 | * @dev: device | |
306 | * | |
307 | * Allows using generic clock names for drivers by adding a new alias. | |
308 | * Assumes clkdev, see clkdev.h for more info. | |
309 | */ | |
310 | int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, | |
311 | struct device *dev); | |
312 | ||
1da177e4 | 313 | #endif |