blob: b9d46fa154b40f065449b901ae5982503e1e4430 [file] [log] [blame]
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.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
Todd Poynor686f8c52006-03-25 18:15:24 +000011#ifndef __LINUX_CLK_H
12#define __LINUX_CLK_H
Linus Torvalds1da177e2005-04-16 15:20:36 -070013
Russell King40d3e0f2011-09-22 11:30:50 +010014#include <linux/kernel.h>
15
Linus Torvalds1da177e2005-04-16 15:20:36 -070016struct device;
17
18/*
19 * The base API.
20 */
21
22
23/*
24 * struct clk - an machine class defined object / cookie.
25 */
26struct clk;
27
28/**
29 * clk_get - lookup and obtain a reference to a clock producer.
30 * @dev: device for clock "consumer"
Russell Kingea3f4ea2005-04-27 18:19:55 +010031 * @id: clock comsumer ID
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 *
33 * Returns a struct clk corresponding to the clock producer, or
Russell Kingea3f4ea2005-04-27 18:19:55 +010034 * valid IS_ERR() condition containing errno. The implementation
35 * uses @dev and @id to determine the clock consumer, and thereby
36 * the clock producer. (IOW, @id may be identical strings, but
37 * clk_get may return different clock producers depending on @dev.)
Russell Kingf47fc0a2006-01-03 18:34:20 +000038 *
39 * Drivers must assume that the clock source is not enabled.
Alex Raimondif7ad1602008-10-15 22:02:03 -070040 *
41 * clk_get should not be called from within interrupt context.
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 */
43struct clk *clk_get(struct device *dev, const char *id);
44
45/**
Russell King40d3e0f2011-09-22 11:30:50 +010046 * clk_prepare - prepare a clock source
47 * @clk: clock source
48 *
49 * This prepares the clock source for use.
50 *
51 * Must not be called from within atomic context.
52 */
53#ifdef CONFIG_HAVE_CLK_PREPARE
54int clk_prepare(struct clk *clk);
55#else
56static inline int clk_prepare(struct clk *clk)
57{
58 might_sleep();
59 return 0;
60}
61#endif
62
63/**
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 * clk_enable - inform the system when the clock source should be running.
65 * @clk: clock source
66 *
67 * If the clock can not be enabled/disabled, this should return success.
68 *
Russell King40d3e0f2011-09-22 11:30:50 +010069 * May be called from atomic contexts.
70 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 * Returns success (0) or negative errno.
72 */
73int clk_enable(struct clk *clk);
74
75/**
76 * clk_disable - inform the system when the clock source is no longer required.
77 * @clk: clock source
Russell Kingf47fc0a2006-01-03 18:34:20 +000078 *
79 * Inform the system that a clock source is no longer required by
80 * a driver and may be shut down.
81 *
Russell King40d3e0f2011-09-22 11:30:50 +010082 * May be called from atomic contexts.
83 *
Russell Kingf47fc0a2006-01-03 18:34:20 +000084 * Implementation detail: if the clock source is shared between
85 * multiple drivers, clk_enable() calls must be balanced by the
86 * same number of clk_disable() calls for the clock source to be
87 * disabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 */
89void clk_disable(struct clk *clk);
90
Russell King40d3e0f2011-09-22 11:30:50 +010091
92/**
93 * clk_unprepare - undo preparation of a clock source
94 * @clk: clock source
95 *
96 * This undoes a previously prepared clock. The caller must balance
97 * the number of prepare and unprepare calls.
98 *
99 * Must not be called from within atomic context.
100 */
101#ifdef CONFIG_HAVE_CLK_PREPARE
102void clk_unprepare(struct clk *clk);
103#else
104static inline void clk_unprepare(struct clk *clk)
105{
106 might_sleep();
107}
108#endif
109
Richard Zhao42c5d522011-11-15 14:47:56 +0800110/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
111static inline int clk_prepare_enable(struct clk *clk)
112{
113 int ret;
114
115 ret = clk_prepare(clk);
116 if (ret)
117 return ret;
118 ret = clk_enable(clk);
119 if (ret)
120 clk_unprepare(clk);
121
122 return ret;
123}
124
125/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
126static inline void clk_disable_unprepare(struct clk *clk)
127{
128 clk_disable(clk);
129 clk_unprepare(clk);
130}
131
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
134 * This is only valid once the clock source has been enabled.
135 * @clk: clock source
136 */
137unsigned long clk_get_rate(struct clk *clk);
138
139/**
140 * clk_put - "free" the clock source
141 * @clk: clock source
Russell Kingf47fc0a2006-01-03 18:34:20 +0000142 *
143 * Note: drivers must ensure that all clk_enable calls made on this
144 * clock source are balanced by clk_disable calls prior to calling
145 * this function.
Alex Raimondif7ad1602008-10-15 22:02:03 -0700146 *
147 * clk_put should not be called from within interrupt context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 */
149void clk_put(struct clk *clk);
150
151
152/*
153 * The remaining APIs are optional for machine class support.
154 */
155
156
157/**
158 * clk_round_rate - adjust a rate to the exact rate a clock can provide
159 * @clk: clock source
160 * @rate: desired clock rate in Hz
161 *
162 * Returns rounded clock rate in Hz, or negative errno.
163 */
164long clk_round_rate(struct clk *clk, unsigned long rate);
165
166/**
167 * clk_set_rate - set the clock rate for a clock source
168 * @clk: clock source
169 * @rate: desired clock rate in Hz
170 *
171 * Returns success (0) or negative errno.
172 */
173int clk_set_rate(struct clk *clk, unsigned long rate);
174
175/**
176 * clk_set_parent - set the parent clock source for this clock
177 * @clk: clock source
178 * @parent: parent clock source
179 *
180 * Returns success (0) or negative errno.
181 */
182int clk_set_parent(struct clk *clk, struct clk *parent);
183
184/**
185 * clk_get_parent - get the parent clock source for this clock
186 * @clk: clock source
187 *
188 * Returns struct clk corresponding to parent clock source, or
189 * valid IS_ERR() condition containing errno.
190 */
191struct clk *clk_get_parent(struct clk *clk);
192
Sascha Hauer05fd8e72009-03-07 12:55:49 +0100193/**
194 * clk_get_sys - get a clock based upon the device name
195 * @dev_id: device name
196 * @con_id: connection ID
197 *
198 * Returns a struct clk corresponding to the clock producer, or
199 * valid IS_ERR() condition containing errno. The implementation
200 * uses @dev_id and @con_id to determine the clock consumer, and
201 * thereby the clock producer. In contrast to clk_get() this function
202 * takes the device name instead of the device itself for identification.
203 *
204 * Drivers must assume that the clock source is not enabled.
205 *
206 * clk_get_sys should not be called from within interrupt context.
207 */
208struct clk *clk_get_sys(const char *dev_id, const char *con_id);
209
Tony Lindgrenc0683032009-06-03 17:43:14 +0100210/**
211 * clk_add_alias - add a new clock alias
212 * @alias: name for clock alias
213 * @alias_dev_name: device name
214 * @id: platform specific clock name
215 * @dev: device
216 *
217 * Allows using generic clock names for drivers by adding a new alias.
218 * Assumes clkdev, see clkdev.h for more info.
219 */
220int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
221 struct device *dev);
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223#endif