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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Russell Kingf8ce2542006-01-07 16:15:52 +00002 * linux/include/linux/clk.h
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Copyright (C) 2004 ARM Limited.
5 * Written by Deep Blue Solutions Limited.
Mike Turquetteb24764902012-03-15 23:11:19 -07006 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
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 */
Todd Poynor686f8c52006-03-25 18:15:24 +000012#ifndef __LINUX_CLK_H
13#define __LINUX_CLK_H
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
Russell King40d3e0f2011-09-22 11:30:50 +010015#include <linux/kernel.h>
Mike Turquetteb24764902012-03-15 23:11:19 -070016#include <linux/notifier.h>
Russell King40d3e0f2011-09-22 11:30:50 +010017
Linus Torvalds1da177e2005-04-16 15:20:36 -070018struct device;
19
Linus Torvalds1da177e2005-04-16 15:20:36 -070020struct clk;
21
Mike Turquetteb24764902012-03-15 23:11:19 -070022#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 *
41 */
42#define PRE_RATE_CHANGE BIT(0)
43#define POST_RATE_CHANGE BIT(1)
44#define ABORT_RATE_CHANGE BIT(2)
45
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 */
57struct clk_notifier {
58 struct clk *clk;
59 struct srcu_notifier_head notifier_head;
60 struct list_head node;
61};
62
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).
73 */
74struct clk_notifier_data {
75 struct clk *clk;
76 unsigned long old_rate;
77 unsigned long new_rate;
78};
79
80int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
81
82int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
83
84#endif /* !CONFIG_COMMON_CLK */
85
Linus Torvalds1da177e2005-04-16 15:20:36 -070086/**
87 * clk_get - lookup and obtain a reference to a clock producer.
88 * @dev: device for clock "consumer"
Russell Kingea3f4ea2005-04-27 18:19:55 +010089 * @id: clock comsumer ID
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 *
91 * Returns a struct clk corresponding to the clock producer, or
Russell Kingea3f4ea2005-04-27 18:19:55 +010092 * 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.)
Russell Kingf47fc0a2006-01-03 18:34:20 +000096 *
97 * Drivers must assume that the clock source is not enabled.
Alex Raimondif7ad1602008-10-15 22:02:03 -070098 *
99 * clk_get should not be called from within interrupt context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 */
101struct clk *clk_get(struct device *dev, const char *id);
102
103/**
Russell King40d3e0f2011-09-22 11:30:50 +0100104 * clk_prepare - prepare a clock source
105 * @clk: clock source
106 *
107 * This prepares the clock source for use.
108 *
109 * Must not be called from within atomic context.
110 */
111#ifdef CONFIG_HAVE_CLK_PREPARE
112int clk_prepare(struct clk *clk);
113#else
114static inline int clk_prepare(struct clk *clk)
115{
116 might_sleep();
117 return 0;
118}
119#endif
120
121/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 * clk_enable - inform the system when the clock source should be running.
123 * @clk: clock source
124 *
125 * If the clock can not be enabled/disabled, this should return success.
126 *
Russell King40d3e0f2011-09-22 11:30:50 +0100127 * May be called from atomic contexts.
128 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 * Returns success (0) or negative errno.
130 */
131int clk_enable(struct clk *clk);
132
133/**
134 * clk_disable - inform the system when the clock source is no longer required.
135 * @clk: clock source
Russell Kingf47fc0a2006-01-03 18:34:20 +0000136 *
137 * Inform the system that a clock source is no longer required by
138 * a driver and may be shut down.
139 *
Russell King40d3e0f2011-09-22 11:30:50 +0100140 * May be called from atomic contexts.
141 *
Russell Kingf47fc0a2006-01-03 18:34:20 +0000142 * Implementation detail: if the clock source is shared between
143 * multiple drivers, clk_enable() calls must be balanced by the
144 * same number of clk_disable() calls for the clock source to be
145 * disabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 */
147void clk_disable(struct clk *clk);
148
Russell King40d3e0f2011-09-22 11:30:50 +0100149
150/**
151 * clk_unprepare - undo preparation of a clock source
152 * @clk: clock source
153 *
154 * This undoes a previously prepared clock. The caller must balance
155 * the number of prepare and unprepare calls.
156 *
157 * Must not be called from within atomic context.
158 */
159#ifdef CONFIG_HAVE_CLK_PREPARE
160void clk_unprepare(struct clk *clk);
161#else
162static inline void clk_unprepare(struct clk *clk)
163{
164 might_sleep();
165}
166#endif
167
Richard Zhao42c5d522011-11-15 14:47:56 +0800168/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
169static inline int clk_prepare_enable(struct clk *clk)
170{
171 int ret;
172
173 ret = clk_prepare(clk);
174 if (ret)
175 return ret;
176 ret = clk_enable(clk);
177 if (ret)
178 clk_unprepare(clk);
179
180 return ret;
181}
182
183/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
184static inline void clk_disable_unprepare(struct clk *clk)
185{
186 clk_disable(clk);
187 clk_unprepare(clk);
188}
189
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
192 * This is only valid once the clock source has been enabled.
193 * @clk: clock source
194 */
195unsigned long clk_get_rate(struct clk *clk);
196
197/**
198 * clk_put - "free" the clock source
199 * @clk: clock source
Russell Kingf47fc0a2006-01-03 18:34:20 +0000200 *
201 * Note: drivers must ensure that all clk_enable calls made on this
202 * clock source are balanced by clk_disable calls prior to calling
203 * this function.
Alex Raimondif7ad1602008-10-15 22:02:03 -0700204 *
205 * clk_put should not be called from within interrupt context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 */
207void clk_put(struct clk *clk);
208
209
210/*
211 * The remaining APIs are optional for machine class support.
212 */
213
214
215/**
216 * clk_round_rate - adjust a rate to the exact rate a clock can provide
217 * @clk: clock source
218 * @rate: desired clock rate in Hz
219 *
220 * Returns rounded clock rate in Hz, or negative errno.
221 */
222long clk_round_rate(struct clk *clk, unsigned long rate);
223
224/**
225 * clk_set_rate - set the clock rate for a clock source
226 * @clk: clock source
227 * @rate: desired clock rate in Hz
228 *
229 * Returns success (0) or negative errno.
230 */
231int clk_set_rate(struct clk *clk, unsigned long rate);
232
233/**
234 * clk_set_parent - set the parent clock source for this clock
235 * @clk: clock source
236 * @parent: parent clock source
237 *
238 * Returns success (0) or negative errno.
239 */
240int clk_set_parent(struct clk *clk, struct clk *parent);
241
242/**
243 * clk_get_parent - get the parent clock source for this clock
244 * @clk: clock source
245 *
246 * Returns struct clk corresponding to parent clock source, or
247 * valid IS_ERR() condition containing errno.
248 */
249struct clk *clk_get_parent(struct clk *clk);
250
Sascha Hauer05fd8e72009-03-07 12:55:49 +0100251/**
252 * clk_get_sys - get a clock based upon the device name
253 * @dev_id: device name
254 * @con_id: connection ID
255 *
256 * Returns a struct clk corresponding to the clock producer, or
257 * valid IS_ERR() condition containing errno. The implementation
258 * uses @dev_id and @con_id to determine the clock consumer, and
259 * thereby the clock producer. In contrast to clk_get() this function
260 * takes the device name instead of the device itself for identification.
261 *
262 * Drivers must assume that the clock source is not enabled.
263 *
264 * clk_get_sys should not be called from within interrupt context.
265 */
266struct clk *clk_get_sys(const char *dev_id, const char *con_id);
267
Tony Lindgrenc0683032009-06-03 17:43:14 +0100268/**
269 * clk_add_alias - add a new clock alias
270 * @alias: name for clock alias
271 * @alias_dev_name: device name
272 * @id: platform specific clock name
273 * @dev: device
274 *
275 * Allows using generic clock names for drivers by adding a new alias.
276 * Assumes clkdev, see clkdev.h for more info.
277 */
278int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
279 struct device *dev);
280
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281#endif