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 struct clk;
  21 struct device_node;
  22 struct of_phandle_args;
  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, NOTIFY_OK,
  31  *     NOTIFY_STOP or NOTIFY_BAD.
  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 or NOTIFY_OK.
  37  *
  38  * POST_RATE_CHANGE - called after the clk rate change has successfully
  39  *     completed.  Callbacks must always return NOTIFY_DONE or NOTIFY_OK.
  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 /**
  81  * struct clk_bulk_data - Data used for bulk clk operations.
  82  *
  83  * @id: clock consumer ID
  84  * @clk: struct clk * to store the associated clock
  85  *
  86  * The CLK APIs provide a series of clk_bulk_() API calls as
  87  * a convenience to consumers which require multiple clks.  This
  88  * structure is used to manage data for these calls.
  89  */
  90 struct clk_bulk_data {
  91         const char              *id;
  92         struct clk              *clk;
  93 };
  94
  95 #ifdef CONFIG_COMMON_CLK
  96
  97 /**
  98  * clk_notifier_register: register a clock rate-change notifier callback
  99  * @clk: clock whose rate we are interested in
 100  * @nb: notifier block with callback function pointer
 101  *
 102  * ProTip: debugging across notifier chains can be frustrating. Make sure that
 103  * your notifier callback function prints a nice big warning in case of
 104  * failure.
 105  */
 106 int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
 107
 108 /**
 109  * clk_notifier_unregister: unregister a clock rate-change notifier callback
 110  * @clk: clock whose rate we are no longer interested in
 111  * @nb: notifier block which will be unregistered
 112  */
 113 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
 114
 115 /**
 116  * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion)
 117  *                    for a clock source.
 118  * @clk: clock source
 119  *
 120  * This gets the clock source accuracy expressed in ppb.
 121  * A perfect clock returns 0.
 122  */
 123 long clk_get_accuracy(struct clk *clk);
 124
 125 /**
 126  * clk_set_phase - adjust the phase shift of a clock signal
 127  * @clk: clock signal source
 128  * @degrees: number of degrees the signal is shifted
 129  *
 130  * Shifts the phase of a clock signal by the specified degrees. Returns 0 on
 131  * success, -EERROR otherwise.
 132  */
 133 int clk_set_phase(struct clk *clk, int degrees);
 134
 135 /**
 136  * clk_get_phase - return the phase shift of a clock signal
 137  * @clk: clock signal source
 138  *
 139  * Returns the phase shift of a clock node in degrees, otherwise returns
 140  * -EERROR.
 141  */
 142 int clk_get_phase(struct clk *clk);
 143
 144 /**
 145  * clk_set_duty_cycle - adjust the duty cycle ratio of a clock signal
 146  * @clk: clock signal source
 147  * @num: numerator of the duty cycle ratio to be applied
 148  * @den: denominator of the duty cycle ratio to be applied
 149  *
 150  * Adjust the duty cycle of a clock signal by the specified ratio. Returns 0 on
 151  * success, -EERROR otherwise.
 152  */
 153 int clk_set_duty_cycle(struct clk *clk, unsigned int num, unsigned int den);
 154
 155 /**
 156  * clk_get_duty_cycle - return the duty cycle ratio of a clock signal
 157  * @clk: clock signal source
 158  * @scale: scaling factor to be applied to represent the ratio as an integer
 159  *
 160  * Returns the duty cycle ratio multiplied by the scale provided, otherwise
 161  * returns -EERROR.
 162  */
 163 int clk_get_scaled_duty_cycle(struct clk *clk, unsigned int scale);
 164
 165 /**
 166  * clk_is_match - check if two clk's point to the same hardware clock
 167  * @p: clk compared against q
 168  * @q: clk compared against p
 169  *
 170  * Returns true if the two struct clk pointers both point to the same hardware
 171  * clock node. Put differently, returns true if @p and @q
 172  * share the same &struct clk_core object.
 173  *
 174  * Returns false otherwise. Note that two NULL clks are treated as matching.
 175  */
 176 bool clk_is_match(const struct clk *p, const struct clk *q);
 177
 178 #else
 179
 180 static inline int clk_notifier_register(struct clk *clk,
 181                                         struct notifier_block *nb)
 182 {
 183         return -ENOTSUPP;
 184 }
 185
 186 static inline int clk_notifier_unregister(struct clk *clk,
 187                                           struct notifier_block *nb)
 188 {
 189         return -ENOTSUPP;
 190 }
 191
 192 static inline long clk_get_accuracy(struct clk *clk)
 193 {
 194         return -ENOTSUPP;
 195 }
 196
 197 static inline long clk_set_phase(struct clk *clk, int phase)
 198 {
 199         return -ENOTSUPP;
 200 }
 201
 202 static inline long clk_get_phase(struct clk *clk)
 203 {
 204         return -ENOTSUPP;
 205 }
 206
 207 static inline int clk_set_duty_cycle(struct clk *clk, unsigned int num,
 208                                      unsigned int den)
 209 {
 210         return -ENOTSUPP;
 211 }
 212
 213 static inline unsigned int clk_get_scaled_duty_cycle(struct clk *clk,
 214                                                      unsigned int scale)
 215 {
 216         return 0;
 217 }
 218
 219 static inline bool clk_is_match(const struct clk *p, const struct clk *q)
 220 {
 221         return p == q;
 222 }
 223
 224 #endif
 225
 226 /**
 227  * clk_prepare - prepare a clock source
 228  * @clk: clock source
 229  *
 230  * This prepares the clock source for use.
 231  *
 232  * Must not be called from within atomic context.
 233  */
 234 #ifdef CONFIG_HAVE_CLK_PREPARE
 235 int clk_prepare(struct clk *clk);
 236 int __must_check clk_bulk_prepare(int num_clks,
 237                                   const struct clk_bulk_data *clks);
 238 #else
 239 static inline int clk_prepare(struct clk *clk)
 240 {
 241         might_sleep();
 242         return 0;
 243 }
 244
 245 static inline int __must_check clk_bulk_prepare(int num_clks, struct clk_bulk_data *clks)
 246 {
 247         might_sleep();
 248         return 0;
 249 }
 250 #endif
 251
 252 /**
 253  * clk_unprepare - undo preparation of a clock source
 254  * @clk: clock source
 255  *
 256  * This undoes a previously prepared clock.  The caller must balance
 257  * the number of prepare and unprepare calls.
 258  *
 259  * Must not be called from within atomic context.
 260  */
 261 #ifdef CONFIG_HAVE_CLK_PREPARE
 262 void clk_unprepare(struct clk *clk);
 263 void clk_bulk_unprepare(int num_clks, const struct clk_bulk_data *clks);
 264 #else
 265 static inline void clk_unprepare(struct clk *clk)
 266 {
 267         might_sleep();
 268 }
 269 static inline void clk_bulk_unprepare(int num_clks, struct clk_bulk_data *clks)
 270 {
 271         might_sleep();
 272 }
 273 #endif
 274
 275 #ifdef CONFIG_HAVE_CLK
 276 /**
 277  * clk_get - lookup and obtain a reference to a clock producer.
 278  * @dev: device for clock "consumer"
 279  * @id: clock consumer ID
 280  *
 281  * Returns a struct clk corresponding to the clock producer, or
 282  * valid IS_ERR() condition containing errno.  The implementation
 283  * uses @dev and @id to determine the clock consumer, and thereby
 284  * the clock producer.  (IOW, @id may be identical strings, but
 285  * clk_get may return different clock producers depending on @dev.)
 286  *
 287  * Drivers must assume that the clock source is not enabled.
 288  *
 289  * clk_get should not be called from within interrupt context.
 290  */
 291 struct clk *clk_get(struct device *dev, const char *id);
 292
 293 /**
 294  * clk_bulk_get - lookup and obtain a number of references to clock producer.
 295  * @dev: device for clock "consumer"
 296  * @num_clks: the number of clk_bulk_data
 297  * @clks: the clk_bulk_data table of consumer
 298  *
 299  * This helper function allows drivers to get several clk consumers in one
 300  * operation. If any of the clk cannot be acquired then any clks
 301  * that were obtained will be freed before returning to the caller.
 302  *
 303  * Returns 0 if all clocks specified in clk_bulk_data table are obtained
 304  * successfully, or valid IS_ERR() condition containing errno.
 305  * The implementation uses @dev and @clk_bulk_data.id to determine the
 306  * clock consumer, and thereby the clock producer.
 307  * The clock returned is stored in each @clk_bulk_data.clk field.
 308  *
 309  * Drivers must assume that the clock source is not enabled.
 310  *
 311  * clk_bulk_get should not be called from within interrupt context.
 312  */
 313 int __must_check clk_bulk_get(struct device *dev, int num_clks,
 314                               struct clk_bulk_data *clks);
 315 /**
 316  * clk_bulk_get_all - lookup and obtain all available references to clock
 317  *                    producer.
 318  * @dev: device for clock "consumer"
 319  * @clks: pointer to the clk_bulk_data table of consumer
 320  *
 321  * This helper function allows drivers to get all clk consumers in one
 322  * operation. If any of the clk cannot be acquired then any clks
 323  * that were obtained will be freed before returning to the caller.
 324  *
 325  * Returns a positive value for the number of clocks obtained while the
 326  * clock references are stored in the clk_bulk_data table in @clks field.
 327  * Returns 0 if there're none and a negative value if something failed.
 328  *
 329  * Drivers must assume that the clock source is not enabled.
 330  *
 331  * clk_bulk_get should not be called from within interrupt context.
 332  */
 333 int __must_check clk_bulk_get_all(struct device *dev,
 334                                   struct clk_bulk_data **clks);
 335 /**
 336  * devm_clk_bulk_get - managed get multiple clk consumers
 337  * @dev: device for clock "consumer"
 338  * @num_clks: the number of clk_bulk_data
 339  * @clks: the clk_bulk_data table of consumer
 340  *
 341  * Return 0 on success, an errno on failure.
 342  *
 343  * This helper function allows drivers to get several clk
 344  * consumers in one operation with management, the clks will
 345  * automatically be freed when the device is unbound.
 346  */
 347 int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
 348                                    struct clk_bulk_data *clks);
 349 /**
 350  * devm_clk_bulk_get_all - managed get multiple clk consumers
 351  * @dev: device for clock "consumer"
 352  * @clks: pointer to the clk_bulk_data table of consumer
 353  *
 354  * Returns a positive value for the number of clocks obtained while the
 355  * clock references are stored in the clk_bulk_data table in @clks field.
 356  * Returns 0 if there're none and a negative value if something failed.
 357  *
 358  * This helper function allows drivers to get several clk
 359  * consumers in one operation with management, the clks will
 360  * automatically be freed when the device is unbound.
 361  */
 362
 363 int __must_check devm_clk_bulk_get_all(struct device *dev,
 364                                        struct clk_bulk_data **clks);
 365
 366 /**
 367  * devm_clk_get - lookup and obtain a managed reference to a clock producer.
 368  * @dev: device for clock "consumer"
 369  * @id: clock consumer ID
 370  *
 371  * Returns a struct clk corresponding to the clock producer, or
 372  * valid IS_ERR() condition containing errno.  The implementation
 373  * uses @dev and @id to determine the clock consumer, and thereby
 374  * the clock producer.  (IOW, @id may be identical strings, but
 375  * clk_get may return different clock producers depending on @dev.)
 376  *
 377  * Drivers must assume that the clock source is not enabled.
 378  *
 379  * devm_clk_get should not be called from within interrupt context.
 380  *
 381  * The clock will automatically be freed when the device is unbound
 382  * from the bus.
 383  */
 384 struct clk *devm_clk_get(struct device *dev, const char *id);
 385
 386 /**
 387  * devm_clk_get_optional - lookup and obtain a managed reference to an optional
 388  *                         clock producer.
 389  * @dev: device for clock "consumer"
 390  * @id: clock consumer ID
 391  *
 392  * Behaves the same as devm_clk_get() except where there is no clock producer.
 393  * In this case, instead of returning -ENOENT, the function returns NULL.
 394  */
 395 struct clk *devm_clk_get_optional(struct device *dev, const char *id);
 396
 397 /**
 398  * devm_get_clk_from_child - lookup and obtain a managed reference to a
 399  *                           clock producer from child node.
 400  * @dev: device for clock "consumer"
 401  * @np: pointer to clock consumer node
 402  * @con_id: clock consumer ID
 403  *
 404  * This function parses the clocks, and uses them to look up the
 405  * struct clk from the registered list of clock providers by using
 406  * @np and @con_id
 407  *
 408  * The clock will automatically be freed when the device is unbound
 409  * from the bus.
 410  */
 411 struct clk *devm_get_clk_from_child(struct device *dev,
 412                                     struct device_node *np, const char *con_id);
 413 /**
 414  * clk_rate_exclusive_get - get exclusivity over the rate control of a
 415  *                          producer
 416  * @clk: clock source
 417  *
 418  * This function allows drivers to get exclusive control over the rate of a
 419  * provider. It prevents any other consumer to execute, even indirectly,
 420  * opereation which could alter the rate of the provider or cause glitches
 421  *
 422  * If exlusivity is claimed more than once on clock, even by the same driver,
 423  * the rate effectively gets locked as exclusivity can't be preempted.
 424  *
 425  * Must not be called from within atomic context.
 426  *
 427  * Returns success (0) or negative errno.
 428  */
 429 int clk_rate_exclusive_get(struct clk *clk);
 430
 431 /**
 432  * clk_rate_exclusive_put - release exclusivity over the rate control of a
 433  *                          producer
 434  * @clk: clock source
 435  *
 436  * This function allows drivers to release the exclusivity it previously got
 437  * from clk_rate_exclusive_get()
 438  *
 439  * The caller must balance the number of clk_rate_exclusive_get() and
 440  * clk_rate_exclusive_put() calls.
 441  *
 442  * Must not be called from within atomic context.
 443  */
 444 void clk_rate_exclusive_put(struct clk *clk);
 445
 446 /**
 447  * clk_enable - inform the system when the clock source should be running.
 448  * @clk: clock source
 449  *
 450  * If the clock can not be enabled/disabled, this should return success.
 451  *
 452  * May be called from atomic contexts.
 453  *
 454  * Returns success (0) or negative errno.
 455  */
 456 int clk_enable(struct clk *clk);
 457
 458 /**
 459  * clk_bulk_enable - inform the system when the set of clks should be running.
 460  * @num_clks: the number of clk_bulk_data
 461  * @clks: the clk_bulk_data table of consumer
 462  *
 463  * May be called from atomic contexts.
 464  *
 465  * Returns success (0) or negative errno.
 466  */
 467 int __must_check clk_bulk_enable(int num_clks,
 468                                  const struct clk_bulk_data *clks);
 469
 470 /**
 471  * clk_disable - inform the system when the clock source is no longer required.
 472  * @clk: clock source
 473  *
 474  * Inform the system that a clock source is no longer required by
 475  * a driver and may be shut down.
 476  *
 477  * May be called from atomic contexts.
 478  *
 479  * Implementation detail: if the clock source is shared between
 480  * multiple drivers, clk_enable() calls must be balanced by the
 481  * same number of clk_disable() calls for the clock source to be
 482  * disabled.
 483  */
 484 void clk_disable(struct clk *clk);
 485
 486 /**
 487  * clk_bulk_disable - inform the system when the set of clks is no
 488  *                    longer required.
 489  * @num_clks: the number of clk_bulk_data
 490  * @clks: the clk_bulk_data table of consumer
 491  *
 492  * Inform the system that a set of clks is no longer required by
 493  * a driver and may be shut down.
 494  *
 495  * May be called from atomic contexts.
 496  *
 497  * Implementation detail: if the set of clks is shared between
 498  * multiple drivers, clk_bulk_enable() calls must be balanced by the
 499  * same number of clk_bulk_disable() calls for the clock source to be
 500  * disabled.
 501  */
 502 void clk_bulk_disable(int num_clks, const struct clk_bulk_data *clks);
 503
 504 /**
 505  * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
 506  *                This is only valid once the clock source has been enabled.
 507  * @clk: clock source
 508  */
 509 unsigned long clk_get_rate(struct clk *clk);
 510
 511 /**
 512  * clk_put      - "free" the clock source
 513  * @clk: clock source
 514  *
 515  * Note: drivers must ensure that all clk_enable calls made on this
 516  * clock source are balanced by clk_disable calls prior to calling
 517  * this function.
 518  *
 519  * clk_put should not be called from within interrupt context.
 520  */
 521 void clk_put(struct clk *clk);
 522
 523 /**
 524  * clk_bulk_put - "free" the clock source
 525  * @num_clks: the number of clk_bulk_data
 526  * @clks: the clk_bulk_data table of consumer
 527  *
 528  * Note: drivers must ensure that all clk_bulk_enable calls made on this
 529  * clock source are balanced by clk_bulk_disable calls prior to calling
 530  * this function.
 531  *
 532  * clk_bulk_put should not be called from within interrupt context.
 533  */
 534 void clk_bulk_put(int num_clks, struct clk_bulk_data *clks);
 535
 536 /**
 537  * clk_bulk_put_all - "free" all the clock source
 538  * @num_clks: the number of clk_bulk_data
 539  * @clks: the clk_bulk_data table of consumer
 540  *
 541  * Note: drivers must ensure that all clk_bulk_enable calls made on this
 542  * clock source are balanced by clk_bulk_disable calls prior to calling
 543  * this function.
 544  *
 545  * clk_bulk_put_all should not be called from within interrupt context.
 546  */
 547 void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks);
 548
 549 /**
 550  * devm_clk_put - "free" a managed clock source
 551  * @dev: device used to acquire the clock
 552  * @clk: clock source acquired with devm_clk_get()
 553  *
 554  * Note: drivers must ensure that all clk_enable calls made on this
 555  * clock source are balanced by clk_disable calls prior to calling
 556  * this function.
 557  *
 558  * clk_put should not be called from within interrupt context.
 559  */
 560 void devm_clk_put(struct device *dev, struct clk *clk);
 561
 562 /*
 563  * The remaining APIs are optional for machine class support.
 564  */
 565
 566
 567 /**
 568  * clk_round_rate - adjust a rate to the exact rate a clock can provide
 569  * @clk: clock source
 570  * @rate: desired clock rate in Hz
 571  *
 572  * This answers the question "if I were to pass @rate to clk_set_rate(),
 573  * what clock rate would I end up with?" without changing the hardware
 574  * in any way.  In other words:
 575  *
 576  *   rate = clk_round_rate(clk, r);
 577  *
 578  * and:
 579  *
 580  *   clk_set_rate(clk, r);
 581  *   rate = clk_get_rate(clk);
 582  *
 583  * are equivalent except the former does not modify the clock hardware
 584  * in any way.
 585  *
 586  * Returns rounded clock rate in Hz, or negative errno.
 587  */
 588 long clk_round_rate(struct clk *clk, unsigned long rate);
 589
 590 /**
 591  * clk_set_rate - set the clock rate for a clock source
 592  * @clk: clock source
 593  * @rate: desired clock rate in Hz
 594  *
 595  * Returns success (0) or negative errno.
 596  */
 597 int clk_set_rate(struct clk *clk, unsigned long rate);
 598
 599 /**
 600  * clk_set_rate_exclusive- set the clock rate and claim exclusivity over
 601  *                         clock source
 602  * @clk: clock source
 603  * @rate: desired clock rate in Hz
 604  *
 605  * This helper function allows drivers to atomically set the rate of a producer
 606  * and claim exclusivity over the rate control of the producer.
 607  *
 608  * It is essentially a combination of clk_set_rate() and
 609  * clk_rate_exclusite_get(). Caller must balance this call with a call to
 610  * clk_rate_exclusive_put()
 611  *
 612  * Returns success (0) or negative errno.
 613  */
 614 int clk_set_rate_exclusive(struct clk *clk, unsigned long rate);
 615
 616 /**
 617  * clk_has_parent - check if a clock is a possible parent for another
 618  * @clk: clock source
 619  * @parent: parent clock source
 620  *
 621  * This function can be used in drivers that need to check that a clock can be
 622  * the parent of another without actually changing the parent.
 623  *
 624  * Returns true if @parent is a possible parent for @clk, false otherwise.
 625  */
 626 bool clk_has_parent(struct clk *clk, struct clk *parent);
 627
 628 /**
 629  * clk_set_rate_range - set a rate range for a clock source
 630  * @clk: clock source
 631  * @min: desired minimum clock rate in Hz, inclusive
 632  * @max: desired maximum clock rate in Hz, inclusive
 633  *
 634  * Returns success (0) or negative errno.
 635  */
 636 int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max);
 637
 638 /**
 639  * clk_set_min_rate - set a minimum clock rate for a clock source
 640  * @clk: clock source
 641  * @rate: desired minimum clock rate in Hz, inclusive
 642  *
 643  * Returns success (0) or negative errno.
 644  */
 645 int clk_set_min_rate(struct clk *clk, unsigned long rate);
 646
 647 /**
 648  * clk_set_max_rate - set a maximum clock rate for a clock source
 649  * @clk: clock source
 650  * @rate: desired maximum clock rate in Hz, inclusive
 651  *
 652  * Returns success (0) or negative errno.
 653  */
 654 int clk_set_max_rate(struct clk *clk, unsigned long rate);
 655
 656 /**
 657  * clk_set_parent - set the parent clock source for this clock
 658  * @clk: clock source
 659  * @parent: parent clock source
 660  *
 661  * Returns success (0) or negative errno.
 662  */
 663 int clk_set_parent(struct clk *clk, struct clk *parent);
 664
 665 /**
 666  * clk_get_parent - get the parent clock source for this clock
 667  * @clk: clock source
 668  *
 669  * Returns struct clk corresponding to parent clock source, or
 670  * valid IS_ERR() condition containing errno.
 671  */
 672 struct clk *clk_get_parent(struct clk *clk);
 673
 674 /**
 675  * clk_get_sys - get a clock based upon the device name
 676  * @dev_id: device name
 677  * @con_id: connection ID
 678  *
 679  * Returns a struct clk corresponding to the clock producer, or
 680  * valid IS_ERR() condition containing errno.  The implementation
 681  * uses @dev_id and @con_id to determine the clock consumer, and
 682  * thereby the clock producer. In contrast to clk_get() this function
 683  * takes the device name instead of the device itself for identification.
 684  *
 685  * Drivers must assume that the clock source is not enabled.
 686  *
 687  * clk_get_sys should not be called from within interrupt context.
 688  */
 689 struct clk *clk_get_sys(const char *dev_id, const char *con_id);
 690
 691 /**
 692  * clk_save_context - save clock context for poweroff
 693  *
 694  * Saves the context of the clock register for powerstates in which the
 695  * contents of the registers will be lost. Occurs deep within the suspend
 696  * code so locking is not necessary.
 697  */
 698 int clk_save_context(void);
 699
 700 /**
 701  * clk_restore_context - restore clock context after poweroff
 702  *
 703  * This occurs with all clocks enabled. Occurs deep within the resume code
 704  * so locking is not necessary.
 705  */
 706 void clk_restore_context(void);
 707
 708 #else /* !CONFIG_HAVE_CLK */
 709
 710 static inline struct clk *clk_get(struct device *dev, const char *id)
 711 {
 712         return NULL;
 713 }
 714
 715 static inline int __must_check clk_bulk_get(struct device *dev, int num_clks,
 716                                             struct clk_bulk_data *clks)
 717 {
 718         return 0;
 719 }
 720
 721 static inline int __must_check clk_bulk_get_all(struct device *dev,
 722                                          struct clk_bulk_data **clks)
 723 {
 724         return 0;
 725 }
 726
 727 static inline struct clk *devm_clk_get(struct device *dev, const char *id)
 728 {
 729         return NULL;
 730 }
 731
 732 static inline struct clk *devm_clk_get_optional(struct device *dev,
 733                                                 const char *id)
 734 {
 735         return NULL;
 736 }
 737
 738 static inline int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
 739                                                  struct clk_bulk_data *clks)
 740 {
 741         return 0;
 742 }
 743
 744 static inline int __must_check devm_clk_bulk_get_all(struct device *dev,
 745                                                      struct clk_bulk_data **clks)
 746 {
 747
 748         return 0;
 749 }
 750
 751 static inline struct clk *devm_get_clk_from_child(struct device *dev,
 752                                 struct device_node *np, const char *con_id)
 753 {
 754         return NULL;
 755 }
 756
 757 static inline void clk_put(struct clk *clk) {}
 758
 759 static inline void clk_bulk_put(int num_clks, struct clk_bulk_data *clks) {}
 760
 761 static inline void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks) {}
 762
 763 static inline void devm_clk_put(struct device *dev, struct clk *clk) {}
 764
 765
 766 static inline int clk_rate_exclusive_get(struct clk *clk)
 767 {
 768         return 0;
 769 }
 770
 771 static inline void clk_rate_exclusive_put(struct clk *clk) {}
 772
 773 static inline int clk_enable(struct clk *clk)
 774 {
 775         return 0;
 776 }
 777
 778 static inline int __must_check clk_bulk_enable(int num_clks, struct clk_bulk_data *clks)
 779 {
 780         return 0;
 781 }
 782
 783 static inline void clk_disable(struct clk *clk) {}
 784
 785
 786 static inline void clk_bulk_disable(int num_clks,
 787                                     struct clk_bulk_data *clks) {}
 788
 789 static inline unsigned long clk_get_rate(struct clk *clk)
 790 {
 791         return 0;
 792 }
 793
 794 static inline int clk_set_rate(struct clk *clk, unsigned long rate)
 795 {
 796         return 0;
 797 }
 798
 799 static inline int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
 800 {
 801         return 0;
 802 }
 803
 804 static inline long clk_round_rate(struct clk *clk, unsigned long rate)
 805 {
 806         return 0;
 807 }
 808
 809 static inline bool clk_has_parent(struct clk *clk, struct clk *parent)
 810 {
 811         return true;
 812 }
 813
 814 static inline int clk_set_parent(struct clk *clk, struct clk *parent)
 815 {
 816         return 0;
 817 }
 818
 819 static inline struct clk *clk_get_parent(struct clk *clk)
 820 {
 821         return NULL;
 822 }
 823
 824 static inline struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 825 {
 826         return NULL;
 827 }
 828
 829 static inline int clk_save_context(void)
 830 {
 831         return 0;
 832 }
 833
 834 static inline void clk_restore_context(void) {}
 835
 836 #endif
 837
 838 /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
 839 static inline int clk_prepare_enable(struct clk *clk)
 840 {
 841         int ret;
 842
 843         ret = clk_prepare(clk);
 844         if (ret)
 845                 return ret;
 846         ret = clk_enable(clk);
 847         if (ret)
 848                 clk_unprepare(clk);
 849
 850         return ret;
 851 }
 852
 853 /* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
 854 static inline void clk_disable_unprepare(struct clk *clk)
 855 {
 856         clk_disable(clk);
 857         clk_unprepare(clk);
 858 }
 859
 860 static inline int __must_check clk_bulk_prepare_enable(int num_clks,
 861                                         struct clk_bulk_data *clks)
 862 {
 863         int ret;
 864
 865         ret = clk_bulk_prepare(num_clks, clks);
 866         if (ret)
 867                 return ret;
 868         ret = clk_bulk_enable(num_clks, clks);
 869         if (ret)
 870                 clk_bulk_unprepare(num_clks, clks);
 871
 872         return ret;
 873 }
 874
 875 static inline void clk_bulk_disable_unprepare(int num_clks,
 876                                               struct clk_bulk_data *clks)
 877 {
 878         clk_bulk_disable(num_clks, clks);
 879         clk_bulk_unprepare(num_clks, clks);
 880 }
 881
 882 /**
 883  * clk_get_optional - lookup and obtain a reference to an optional clock
 884  *                    producer.
 885  * @dev: device for clock "consumer"
 886  * @id: clock consumer ID
 887  *
 888  * Behaves the same as clk_get() except where there is no clock producer. In
 889  * this case, instead of returning -ENOENT, the function returns NULL.
 890  */
 891 static inline struct clk *clk_get_optional(struct device *dev, const char *id)
 892 {
 893         struct clk *clk = clk_get(dev, id);
 894
 895         if (clk == ERR_PTR(-ENOENT))
 896                 return NULL;
 897
 898         return clk;
 899 }
 900
 901 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
 902 struct clk *of_clk_get(struct device_node *np, int index);
 903 struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
 904 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
 905 #else
 906 static inline struct clk *of_clk_get(struct device_node *np, int index)
 907 {
 908         return ERR_PTR(-ENOENT);
 909 }
 910 static inline struct clk *of_clk_get_by_name(struct device_node *np,
 911                                              const char *name)
 912 {
 913         return ERR_PTR(-ENOENT);
 914 }
 915 static inline struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 916 {
 917         return ERR_PTR(-ENOENT);
 918 }
 919 #endif
 920
 921 #endif