Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Russell King | f8ce254 | 2006-01-07 16:15:52 +0000 | [diff] [blame] | 2 | * linux/include/linux/clk.h |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * |
| 4 | * Copyright (C) 2004 ARM Limited. |
| 5 | * Written by Deep Blue Solutions Limited. |
Mike Turquette | b2476490 | 2012-03-15 23:11:19 -0700 | [diff] [blame] | 6 | * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | */ |
Todd Poynor | 686f8c5 | 2006-03-25 18:15:24 +0000 | [diff] [blame] | 12 | #ifndef __LINUX_CLK_H |
| 13 | #define __LINUX_CLK_H |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | |
Russell King | 40d3e0f | 2011-09-22 11:30:50 +0100 | [diff] [blame] | 15 | #include <linux/kernel.h> |
Mike Turquette | b2476490 | 2012-03-15 23:11:19 -0700 | [diff] [blame] | 16 | #include <linux/notifier.h> |
Russell King | 40d3e0f | 2011-09-22 11:30:50 +0100 | [diff] [blame] | 17 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | struct device; |
| 19 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | struct clk; |
| 21 | |
Mike Turquette | b2476490 | 2012-03-15 23:11:19 -0700 | [diff] [blame] | 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 | * |
| 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 | */ |
| 57 | struct 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 | */ |
| 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 | |
| 84 | #endif /* !CONFIG_COMMON_CLK */ |
| 85 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | /** |
| 87 | * clk_get - lookup and obtain a reference to a clock producer. |
| 88 | * @dev: device for clock "consumer" |
Russell King | ea3f4ea | 2005-04-27 18:19:55 +0100 | [diff] [blame] | 89 | * @id: clock comsumer ID |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | * |
| 91 | * Returns a struct clk corresponding to the clock producer, or |
Russell King | ea3f4ea | 2005-04-27 18:19:55 +0100 | [diff] [blame] | 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.) |
Russell King | f47fc0a | 2006-01-03 18:34:20 +0000 | [diff] [blame] | 96 | * |
| 97 | * Drivers must assume that the clock source is not enabled. |
Alex Raimondi | f7ad160 | 2008-10-15 22:02:03 -0700 | [diff] [blame] | 98 | * |
| 99 | * clk_get should not be called from within interrupt context. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | */ |
| 101 | struct clk *clk_get(struct device *dev, const char *id); |
| 102 | |
| 103 | /** |
Russell King | 40d3e0f | 2011-09-22 11:30:50 +0100 | [diff] [blame] | 104 | * 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 |
| 112 | int clk_prepare(struct clk *clk); |
| 113 | #else |
| 114 | static inline int clk_prepare(struct clk *clk) |
| 115 | { |
| 116 | might_sleep(); |
| 117 | return 0; |
| 118 | } |
| 119 | #endif |
| 120 | |
| 121 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | * 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 King | 40d3e0f | 2011-09-22 11:30:50 +0100 | [diff] [blame] | 127 | * May be called from atomic contexts. |
| 128 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | * Returns success (0) or negative errno. |
| 130 | */ |
| 131 | int 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 King | f47fc0a | 2006-01-03 18:34:20 +0000 | [diff] [blame] | 136 | * |
| 137 | * Inform the system that a clock source is no longer required by |
| 138 | * a driver and may be shut down. |
| 139 | * |
Russell King | 40d3e0f | 2011-09-22 11:30:50 +0100 | [diff] [blame] | 140 | * May be called from atomic contexts. |
| 141 | * |
Russell King | f47fc0a | 2006-01-03 18:34:20 +0000 | [diff] [blame] | 142 | * 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | */ |
| 147 | void clk_disable(struct clk *clk); |
| 148 | |
Russell King | 40d3e0f | 2011-09-22 11:30:50 +0100 | [diff] [blame] | 149 | |
| 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 |
| 160 | void clk_unprepare(struct clk *clk); |
| 161 | #else |
| 162 | static inline void clk_unprepare(struct clk *clk) |
| 163 | { |
| 164 | might_sleep(); |
| 165 | } |
| 166 | #endif |
| 167 | |
Richard Zhao | 42c5d52 | 2011-11-15 14:47:56 +0800 | [diff] [blame] | 168 | /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */ |
| 169 | static 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. */ |
| 184 | static inline void clk_disable_unprepare(struct clk *clk) |
| 185 | { |
| 186 | clk_disable(clk); |
| 187 | clk_unprepare(clk); |
| 188 | } |
| 189 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | * 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 | */ |
| 195 | unsigned long clk_get_rate(struct clk *clk); |
| 196 | |
| 197 | /** |
| 198 | * clk_put - "free" the clock source |
| 199 | * @clk: clock source |
Russell King | f47fc0a | 2006-01-03 18:34:20 +0000 | [diff] [blame] | 200 | * |
| 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 Raimondi | f7ad160 | 2008-10-15 22:02:03 -0700 | [diff] [blame] | 204 | * |
| 205 | * clk_put should not be called from within interrupt context. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | */ |
| 207 | void 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 | */ |
| 222 | long 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 | */ |
| 231 | int 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 | */ |
| 240 | int 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 | */ |
| 249 | struct clk *clk_get_parent(struct clk *clk); |
| 250 | |
Sascha Hauer | 05fd8e7 | 2009-03-07 12:55:49 +0100 | [diff] [blame] | 251 | /** |
| 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 | */ |
| 266 | struct clk *clk_get_sys(const char *dev_id, const char *con_id); |
| 267 | |
Tony Lindgren | c068303 | 2009-06-03 17:43:14 +0100 | [diff] [blame] | 268 | /** |
| 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 | */ |
| 278 | int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, |
| 279 | struct device *dev); |
| 280 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | #endif |