clk.c revision 5279fc402ae59361a224d641d5823b21b4206232
1/* 2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> 3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Standard functionality for the common clock API. See Documentation/clk.txt 10 */ 11 12#include <linux/clk-private.h> 13#include <linux/module.h> 14#include <linux/mutex.h> 15#include <linux/spinlock.h> 16#include <linux/err.h> 17#include <linux/list.h> 18#include <linux/slab.h> 19#include <linux/of.h> 20#include <linux/device.h> 21#include <linux/init.h> 22#include <linux/sched.h> 23 24static DEFINE_SPINLOCK(enable_lock); 25static DEFINE_MUTEX(prepare_lock); 26 27static struct task_struct *prepare_owner; 28static struct task_struct *enable_owner; 29 30static int prepare_refcnt; 31static int enable_refcnt; 32 33static HLIST_HEAD(clk_root_list); 34static HLIST_HEAD(clk_orphan_list); 35static LIST_HEAD(clk_notifier_list); 36 37/*** locking ***/ 38static void clk_prepare_lock(void) 39{ 40 if (!mutex_trylock(&prepare_lock)) { 41 if (prepare_owner == current) { 42 prepare_refcnt++; 43 return; 44 } 45 mutex_lock(&prepare_lock); 46 } 47 WARN_ON_ONCE(prepare_owner != NULL); 48 WARN_ON_ONCE(prepare_refcnt != 0); 49 prepare_owner = current; 50 prepare_refcnt = 1; 51} 52 53static void clk_prepare_unlock(void) 54{ 55 WARN_ON_ONCE(prepare_owner != current); 56 WARN_ON_ONCE(prepare_refcnt == 0); 57 58 if (--prepare_refcnt) 59 return; 60 prepare_owner = NULL; 61 mutex_unlock(&prepare_lock); 62} 63 64static unsigned long clk_enable_lock(void) 65{ 66 unsigned long flags; 67 68 if (!spin_trylock_irqsave(&enable_lock, flags)) { 69 if (enable_owner == current) { 70 enable_refcnt++; 71 return flags; 72 } 73 spin_lock_irqsave(&enable_lock, flags); 74 } 75 WARN_ON_ONCE(enable_owner != NULL); 76 WARN_ON_ONCE(enable_refcnt != 0); 77 enable_owner = current; 78 enable_refcnt = 1; 79 return flags; 80} 81 82static void clk_enable_unlock(unsigned long flags) 83{ 84 WARN_ON_ONCE(enable_owner != current); 85 WARN_ON_ONCE(enable_refcnt == 0); 86 87 if (--enable_refcnt) 88 return; 89 enable_owner = NULL; 90 spin_unlock_irqrestore(&enable_lock, flags); 91} 92 93/*** debugfs support ***/ 94 95#ifdef CONFIG_COMMON_CLK_DEBUG 96#include <linux/debugfs.h> 97 98static struct dentry *rootdir; 99static struct dentry *orphandir; 100static int inited = 0; 101 102static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level) 103{ 104 if (!c) 105 return; 106 107 seq_printf(s, "%*s%-*s %-11d %-12d %-10lu %-11lu", 108 level * 3 + 1, "", 109 30 - level * 3, c->name, 110 c->enable_count, c->prepare_count, clk_get_rate(c), 111 clk_get_accuracy(c)); 112 seq_printf(s, "\n"); 113} 114 115static void clk_summary_show_subtree(struct seq_file *s, struct clk *c, 116 int level) 117{ 118 struct clk *child; 119 120 if (!c) 121 return; 122 123 clk_summary_show_one(s, c, level); 124 125 hlist_for_each_entry(child, &c->children, child_node) 126 clk_summary_show_subtree(s, child, level + 1); 127} 128 129static int clk_summary_show(struct seq_file *s, void *data) 130{ 131 struct clk *c; 132 133 seq_printf(s, " clock enable_cnt prepare_cnt rate accuracy\n"); 134 seq_printf(s, "---------------------------------------------------------------------------------\n"); 135 136 clk_prepare_lock(); 137 138 hlist_for_each_entry(c, &clk_root_list, child_node) 139 clk_summary_show_subtree(s, c, 0); 140 141 hlist_for_each_entry(c, &clk_orphan_list, child_node) 142 clk_summary_show_subtree(s, c, 0); 143 144 clk_prepare_unlock(); 145 146 return 0; 147} 148 149 150static int clk_summary_open(struct inode *inode, struct file *file) 151{ 152 return single_open(file, clk_summary_show, inode->i_private); 153} 154 155static const struct file_operations clk_summary_fops = { 156 .open = clk_summary_open, 157 .read = seq_read, 158 .llseek = seq_lseek, 159 .release = single_release, 160}; 161 162static void clk_dump_one(struct seq_file *s, struct clk *c, int level) 163{ 164 if (!c) 165 return; 166 167 seq_printf(s, "\"%s\": { ", c->name); 168 seq_printf(s, "\"enable_count\": %d,", c->enable_count); 169 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count); 170 seq_printf(s, "\"rate\": %lu", clk_get_rate(c)); 171 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c)); 172} 173 174static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level) 175{ 176 struct clk *child; 177 178 if (!c) 179 return; 180 181 clk_dump_one(s, c, level); 182 183 hlist_for_each_entry(child, &c->children, child_node) { 184 seq_printf(s, ","); 185 clk_dump_subtree(s, child, level + 1); 186 } 187 188 seq_printf(s, "}"); 189} 190 191static int clk_dump(struct seq_file *s, void *data) 192{ 193 struct clk *c; 194 bool first_node = true; 195 196 seq_printf(s, "{"); 197 198 clk_prepare_lock(); 199 200 hlist_for_each_entry(c, &clk_root_list, child_node) { 201 if (!first_node) 202 seq_printf(s, ","); 203 first_node = false; 204 clk_dump_subtree(s, c, 0); 205 } 206 207 hlist_for_each_entry(c, &clk_orphan_list, child_node) { 208 seq_printf(s, ","); 209 clk_dump_subtree(s, c, 0); 210 } 211 212 clk_prepare_unlock(); 213 214 seq_printf(s, "}"); 215 return 0; 216} 217 218 219static int clk_dump_open(struct inode *inode, struct file *file) 220{ 221 return single_open(file, clk_dump, inode->i_private); 222} 223 224static const struct file_operations clk_dump_fops = { 225 .open = clk_dump_open, 226 .read = seq_read, 227 .llseek = seq_lseek, 228 .release = single_release, 229}; 230 231/* caller must hold prepare_lock */ 232static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) 233{ 234 struct dentry *d; 235 int ret = -ENOMEM; 236 237 if (!clk || !pdentry) { 238 ret = -EINVAL; 239 goto out; 240 } 241 242 d = debugfs_create_dir(clk->name, pdentry); 243 if (!d) 244 goto out; 245 246 clk->dentry = d; 247 248 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry, 249 (u32 *)&clk->rate); 250 if (!d) 251 goto err_out; 252 253 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry, 254 (u32 *)&clk->accuracy); 255 if (!d) 256 goto err_out; 257 258 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry, 259 (u32 *)&clk->flags); 260 if (!d) 261 goto err_out; 262 263 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry, 264 (u32 *)&clk->prepare_count); 265 if (!d) 266 goto err_out; 267 268 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry, 269 (u32 *)&clk->enable_count); 270 if (!d) 271 goto err_out; 272 273 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry, 274 (u32 *)&clk->notifier_count); 275 if (!d) 276 goto err_out; 277 278 ret = 0; 279 goto out; 280 281err_out: 282 debugfs_remove_recursive(clk->dentry); 283 clk->dentry = NULL; 284out: 285 return ret; 286} 287 288/* caller must hold prepare_lock */ 289static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry) 290{ 291 struct clk *child; 292 int ret = -EINVAL;; 293 294 if (!clk || !pdentry) 295 goto out; 296 297 ret = clk_debug_create_one(clk, pdentry); 298 299 if (ret) 300 goto out; 301 302 hlist_for_each_entry(child, &clk->children, child_node) 303 clk_debug_create_subtree(child, clk->dentry); 304 305 ret = 0; 306out: 307 return ret; 308} 309 310/** 311 * clk_debug_register - add a clk node to the debugfs clk tree 312 * @clk: the clk being added to the debugfs clk tree 313 * 314 * Dynamically adds a clk to the debugfs clk tree if debugfs has been 315 * initialized. Otherwise it bails out early since the debugfs clk tree 316 * will be created lazily by clk_debug_init as part of a late_initcall. 317 * 318 * Caller must hold prepare_lock. Only clk_init calls this function (so 319 * far) so this is taken care. 320 */ 321static int clk_debug_register(struct clk *clk) 322{ 323 struct clk *parent; 324 struct dentry *pdentry; 325 int ret = 0; 326 327 if (!inited) 328 goto out; 329 330 parent = clk->parent; 331 332 /* 333 * Check to see if a clk is a root clk. Also check that it is 334 * safe to add this clk to debugfs 335 */ 336 if (!parent) 337 if (clk->flags & CLK_IS_ROOT) 338 pdentry = rootdir; 339 else 340 pdentry = orphandir; 341 else 342 if (parent->dentry) 343 pdentry = parent->dentry; 344 else 345 goto out; 346 347 ret = clk_debug_create_subtree(clk, pdentry); 348 349out: 350 return ret; 351} 352 353/** 354 * clk_debug_reparent - reparent clk node in the debugfs clk tree 355 * @clk: the clk being reparented 356 * @new_parent: the new clk parent, may be NULL 357 * 358 * Rename clk entry in the debugfs clk tree if debugfs has been 359 * initialized. Otherwise it bails out early since the debugfs clk tree 360 * will be created lazily by clk_debug_init as part of a late_initcall. 361 * 362 * Caller must hold prepare_lock. 363 */ 364static void clk_debug_reparent(struct clk *clk, struct clk *new_parent) 365{ 366 struct dentry *d; 367 struct dentry *new_parent_d; 368 369 if (!inited) 370 return; 371 372 if (new_parent) 373 new_parent_d = new_parent->dentry; 374 else 375 new_parent_d = orphandir; 376 377 d = debugfs_rename(clk->dentry->d_parent, clk->dentry, 378 new_parent_d, clk->name); 379 if (d) 380 clk->dentry = d; 381 else 382 pr_debug("%s: failed to rename debugfs entry for %s\n", 383 __func__, clk->name); 384} 385 386/** 387 * clk_debug_init - lazily create the debugfs clk tree visualization 388 * 389 * clks are often initialized very early during boot before memory can 390 * be dynamically allocated and well before debugfs is setup. 391 * clk_debug_init walks the clk tree hierarchy while holding 392 * prepare_lock and creates the topology as part of a late_initcall, 393 * thus insuring that clks initialized very early will still be 394 * represented in the debugfs clk tree. This function should only be 395 * called once at boot-time, and all other clks added dynamically will 396 * be done so with clk_debug_register. 397 */ 398static int __init clk_debug_init(void) 399{ 400 struct clk *clk; 401 struct dentry *d; 402 403 rootdir = debugfs_create_dir("clk", NULL); 404 405 if (!rootdir) 406 return -ENOMEM; 407 408 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL, 409 &clk_summary_fops); 410 if (!d) 411 return -ENOMEM; 412 413 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL, 414 &clk_dump_fops); 415 if (!d) 416 return -ENOMEM; 417 418 orphandir = debugfs_create_dir("orphans", rootdir); 419 420 if (!orphandir) 421 return -ENOMEM; 422 423 clk_prepare_lock(); 424 425 hlist_for_each_entry(clk, &clk_root_list, child_node) 426 clk_debug_create_subtree(clk, rootdir); 427 428 hlist_for_each_entry(clk, &clk_orphan_list, child_node) 429 clk_debug_create_subtree(clk, orphandir); 430 431 inited = 1; 432 433 clk_prepare_unlock(); 434 435 return 0; 436} 437late_initcall(clk_debug_init); 438#else 439static inline int clk_debug_register(struct clk *clk) { return 0; } 440static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent) 441{ 442} 443#endif 444 445/* caller must hold prepare_lock */ 446static void clk_unprepare_unused_subtree(struct clk *clk) 447{ 448 struct clk *child; 449 450 if (!clk) 451 return; 452 453 hlist_for_each_entry(child, &clk->children, child_node) 454 clk_unprepare_unused_subtree(child); 455 456 if (clk->prepare_count) 457 return; 458 459 if (clk->flags & CLK_IGNORE_UNUSED) 460 return; 461 462 if (__clk_is_prepared(clk)) { 463 if (clk->ops->unprepare_unused) 464 clk->ops->unprepare_unused(clk->hw); 465 else if (clk->ops->unprepare) 466 clk->ops->unprepare(clk->hw); 467 } 468} 469 470/* caller must hold prepare_lock */ 471static void clk_disable_unused_subtree(struct clk *clk) 472{ 473 struct clk *child; 474 unsigned long flags; 475 476 if (!clk) 477 goto out; 478 479 hlist_for_each_entry(child, &clk->children, child_node) 480 clk_disable_unused_subtree(child); 481 482 flags = clk_enable_lock(); 483 484 if (clk->enable_count) 485 goto unlock_out; 486 487 if (clk->flags & CLK_IGNORE_UNUSED) 488 goto unlock_out; 489 490 /* 491 * some gate clocks have special needs during the disable-unused 492 * sequence. call .disable_unused if available, otherwise fall 493 * back to .disable 494 */ 495 if (__clk_is_enabled(clk)) { 496 if (clk->ops->disable_unused) 497 clk->ops->disable_unused(clk->hw); 498 else if (clk->ops->disable) 499 clk->ops->disable(clk->hw); 500 } 501 502unlock_out: 503 clk_enable_unlock(flags); 504 505out: 506 return; 507} 508 509static bool clk_ignore_unused; 510static int __init clk_ignore_unused_setup(char *__unused) 511{ 512 clk_ignore_unused = true; 513 return 1; 514} 515__setup("clk_ignore_unused", clk_ignore_unused_setup); 516 517static int clk_disable_unused(void) 518{ 519 struct clk *clk; 520 521 if (clk_ignore_unused) { 522 pr_warn("clk: Not disabling unused clocks\n"); 523 return 0; 524 } 525 526 clk_prepare_lock(); 527 528 hlist_for_each_entry(clk, &clk_root_list, child_node) 529 clk_disable_unused_subtree(clk); 530 531 hlist_for_each_entry(clk, &clk_orphan_list, child_node) 532 clk_disable_unused_subtree(clk); 533 534 hlist_for_each_entry(clk, &clk_root_list, child_node) 535 clk_unprepare_unused_subtree(clk); 536 537 hlist_for_each_entry(clk, &clk_orphan_list, child_node) 538 clk_unprepare_unused_subtree(clk); 539 540 clk_prepare_unlock(); 541 542 return 0; 543} 544late_initcall_sync(clk_disable_unused); 545 546/*** helper functions ***/ 547 548const char *__clk_get_name(struct clk *clk) 549{ 550 return !clk ? NULL : clk->name; 551} 552EXPORT_SYMBOL_GPL(__clk_get_name); 553 554struct clk_hw *__clk_get_hw(struct clk *clk) 555{ 556 return !clk ? NULL : clk->hw; 557} 558 559u8 __clk_get_num_parents(struct clk *clk) 560{ 561 return !clk ? 0 : clk->num_parents; 562} 563 564struct clk *__clk_get_parent(struct clk *clk) 565{ 566 return !clk ? NULL : clk->parent; 567} 568 569struct clk *clk_get_parent_by_index(struct clk *clk, u8 index) 570{ 571 if (!clk || index >= clk->num_parents) 572 return NULL; 573 else if (!clk->parents) 574 return __clk_lookup(clk->parent_names[index]); 575 else if (!clk->parents[index]) 576 return clk->parents[index] = 577 __clk_lookup(clk->parent_names[index]); 578 else 579 return clk->parents[index]; 580} 581 582unsigned int __clk_get_enable_count(struct clk *clk) 583{ 584 return !clk ? 0 : clk->enable_count; 585} 586 587unsigned int __clk_get_prepare_count(struct clk *clk) 588{ 589 return !clk ? 0 : clk->prepare_count; 590} 591 592unsigned long __clk_get_rate(struct clk *clk) 593{ 594 unsigned long ret; 595 596 if (!clk) { 597 ret = 0; 598 goto out; 599 } 600 601 ret = clk->rate; 602 603 if (clk->flags & CLK_IS_ROOT) 604 goto out; 605 606 if (!clk->parent) 607 ret = 0; 608 609out: 610 return ret; 611} 612 613unsigned long __clk_get_accuracy(struct clk *clk) 614{ 615 if (!clk) 616 return 0; 617 618 return clk->accuracy; 619} 620 621unsigned long __clk_get_flags(struct clk *clk) 622{ 623 return !clk ? 0 : clk->flags; 624} 625EXPORT_SYMBOL_GPL(__clk_get_flags); 626 627bool __clk_is_prepared(struct clk *clk) 628{ 629 int ret; 630 631 if (!clk) 632 return false; 633 634 /* 635 * .is_prepared is optional for clocks that can prepare 636 * fall back to software usage counter if it is missing 637 */ 638 if (!clk->ops->is_prepared) { 639 ret = clk->prepare_count ? 1 : 0; 640 goto out; 641 } 642 643 ret = clk->ops->is_prepared(clk->hw); 644out: 645 return !!ret; 646} 647 648bool __clk_is_enabled(struct clk *clk) 649{ 650 int ret; 651 652 if (!clk) 653 return false; 654 655 /* 656 * .is_enabled is only mandatory for clocks that gate 657 * fall back to software usage counter if .is_enabled is missing 658 */ 659 if (!clk->ops->is_enabled) { 660 ret = clk->enable_count ? 1 : 0; 661 goto out; 662 } 663 664 ret = clk->ops->is_enabled(clk->hw); 665out: 666 return !!ret; 667} 668 669static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk) 670{ 671 struct clk *child; 672 struct clk *ret; 673 674 if (!strcmp(clk->name, name)) 675 return clk; 676 677 hlist_for_each_entry(child, &clk->children, child_node) { 678 ret = __clk_lookup_subtree(name, child); 679 if (ret) 680 return ret; 681 } 682 683 return NULL; 684} 685 686struct clk *__clk_lookup(const char *name) 687{ 688 struct clk *root_clk; 689 struct clk *ret; 690 691 if (!name) 692 return NULL; 693 694 /* search the 'proper' clk tree first */ 695 hlist_for_each_entry(root_clk, &clk_root_list, child_node) { 696 ret = __clk_lookup_subtree(name, root_clk); 697 if (ret) 698 return ret; 699 } 700 701 /* if not found, then search the orphan tree */ 702 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) { 703 ret = __clk_lookup_subtree(name, root_clk); 704 if (ret) 705 return ret; 706 } 707 708 return NULL; 709} 710 711/* 712 * Helper for finding best parent to provide a given frequency. This can be used 713 * directly as a determine_rate callback (e.g. for a mux), or from a more 714 * complex clock that may combine a mux with other operations. 715 */ 716long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate, 717 unsigned long *best_parent_rate, 718 struct clk **best_parent_p) 719{ 720 struct clk *clk = hw->clk, *parent, *best_parent = NULL; 721 int i, num_parents; 722 unsigned long parent_rate, best = 0; 723 724 /* if NO_REPARENT flag set, pass through to current parent */ 725 if (clk->flags & CLK_SET_RATE_NO_REPARENT) { 726 parent = clk->parent; 727 if (clk->flags & CLK_SET_RATE_PARENT) 728 best = __clk_round_rate(parent, rate); 729 else if (parent) 730 best = __clk_get_rate(parent); 731 else 732 best = __clk_get_rate(clk); 733 goto out; 734 } 735 736 /* find the parent that can provide the fastest rate <= rate */ 737 num_parents = clk->num_parents; 738 for (i = 0; i < num_parents; i++) { 739 parent = clk_get_parent_by_index(clk, i); 740 if (!parent) 741 continue; 742 if (clk->flags & CLK_SET_RATE_PARENT) 743 parent_rate = __clk_round_rate(parent, rate); 744 else 745 parent_rate = __clk_get_rate(parent); 746 if (parent_rate <= rate && parent_rate > best) { 747 best_parent = parent; 748 best = parent_rate; 749 } 750 } 751 752out: 753 if (best_parent) 754 *best_parent_p = best_parent; 755 *best_parent_rate = best; 756 757 return best; 758} 759 760/*** clk api ***/ 761 762void __clk_unprepare(struct clk *clk) 763{ 764 if (!clk) 765 return; 766 767 if (WARN_ON(clk->prepare_count == 0)) 768 return; 769 770 if (--clk->prepare_count > 0) 771 return; 772 773 WARN_ON(clk->enable_count > 0); 774 775 if (clk->ops->unprepare) 776 clk->ops->unprepare(clk->hw); 777 778 __clk_unprepare(clk->parent); 779} 780 781/** 782 * clk_unprepare - undo preparation of a clock source 783 * @clk: the clk being unprepared 784 * 785 * clk_unprepare may sleep, which differentiates it from clk_disable. In a 786 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk 787 * if the operation may sleep. One example is a clk which is accessed over 788 * I2c. In the complex case a clk gate operation may require a fast and a slow 789 * part. It is this reason that clk_unprepare and clk_disable are not mutually 790 * exclusive. In fact clk_disable must be called before clk_unprepare. 791 */ 792void clk_unprepare(struct clk *clk) 793{ 794 clk_prepare_lock(); 795 __clk_unprepare(clk); 796 clk_prepare_unlock(); 797} 798EXPORT_SYMBOL_GPL(clk_unprepare); 799 800int __clk_prepare(struct clk *clk) 801{ 802 int ret = 0; 803 804 if (!clk) 805 return 0; 806 807 if (clk->prepare_count == 0) { 808 ret = __clk_prepare(clk->parent); 809 if (ret) 810 return ret; 811 812 if (clk->ops->prepare) { 813 ret = clk->ops->prepare(clk->hw); 814 if (ret) { 815 __clk_unprepare(clk->parent); 816 return ret; 817 } 818 } 819 } 820 821 clk->prepare_count++; 822 823 return 0; 824} 825 826/** 827 * clk_prepare - prepare a clock source 828 * @clk: the clk being prepared 829 * 830 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple 831 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the 832 * operation may sleep. One example is a clk which is accessed over I2c. In 833 * the complex case a clk ungate operation may require a fast and a slow part. 834 * It is this reason that clk_prepare and clk_enable are not mutually 835 * exclusive. In fact clk_prepare must be called before clk_enable. 836 * Returns 0 on success, -EERROR otherwise. 837 */ 838int clk_prepare(struct clk *clk) 839{ 840 int ret; 841 842 clk_prepare_lock(); 843 ret = __clk_prepare(clk); 844 clk_prepare_unlock(); 845 846 return ret; 847} 848EXPORT_SYMBOL_GPL(clk_prepare); 849 850static void __clk_disable(struct clk *clk) 851{ 852 if (!clk) 853 return; 854 855 if (WARN_ON(IS_ERR(clk))) 856 return; 857 858 if (WARN_ON(clk->enable_count == 0)) 859 return; 860 861 if (--clk->enable_count > 0) 862 return; 863 864 if (clk->ops->disable) 865 clk->ops->disable(clk->hw); 866 867 __clk_disable(clk->parent); 868} 869 870/** 871 * clk_disable - gate a clock 872 * @clk: the clk being gated 873 * 874 * clk_disable must not sleep, which differentiates it from clk_unprepare. In 875 * a simple case, clk_disable can be used instead of clk_unprepare to gate a 876 * clk if the operation is fast and will never sleep. One example is a 877 * SoC-internal clk which is controlled via simple register writes. In the 878 * complex case a clk gate operation may require a fast and a slow part. It is 879 * this reason that clk_unprepare and clk_disable are not mutually exclusive. 880 * In fact clk_disable must be called before clk_unprepare. 881 */ 882void clk_disable(struct clk *clk) 883{ 884 unsigned long flags; 885 886 flags = clk_enable_lock(); 887 __clk_disable(clk); 888 clk_enable_unlock(flags); 889} 890EXPORT_SYMBOL_GPL(clk_disable); 891 892static int __clk_enable(struct clk *clk) 893{ 894 int ret = 0; 895 896 if (!clk) 897 return 0; 898 899 if (WARN_ON(clk->prepare_count == 0)) 900 return -ESHUTDOWN; 901 902 if (clk->enable_count == 0) { 903 ret = __clk_enable(clk->parent); 904 905 if (ret) 906 return ret; 907 908 if (clk->ops->enable) { 909 ret = clk->ops->enable(clk->hw); 910 if (ret) { 911 __clk_disable(clk->parent); 912 return ret; 913 } 914 } 915 } 916 917 clk->enable_count++; 918 return 0; 919} 920 921/** 922 * clk_enable - ungate a clock 923 * @clk: the clk being ungated 924 * 925 * clk_enable must not sleep, which differentiates it from clk_prepare. In a 926 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk 927 * if the operation will never sleep. One example is a SoC-internal clk which 928 * is controlled via simple register writes. In the complex case a clk ungate 929 * operation may require a fast and a slow part. It is this reason that 930 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare 931 * must be called before clk_enable. Returns 0 on success, -EERROR 932 * otherwise. 933 */ 934int clk_enable(struct clk *clk) 935{ 936 unsigned long flags; 937 int ret; 938 939 flags = clk_enable_lock(); 940 ret = __clk_enable(clk); 941 clk_enable_unlock(flags); 942 943 return ret; 944} 945EXPORT_SYMBOL_GPL(clk_enable); 946 947/** 948 * __clk_round_rate - round the given rate for a clk 949 * @clk: round the rate of this clock 950 * @rate: the rate which is to be rounded 951 * 952 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate 953 */ 954unsigned long __clk_round_rate(struct clk *clk, unsigned long rate) 955{ 956 unsigned long parent_rate = 0; 957 struct clk *parent; 958 959 if (!clk) 960 return 0; 961 962 parent = clk->parent; 963 if (parent) 964 parent_rate = parent->rate; 965 966 if (clk->ops->determine_rate) 967 return clk->ops->determine_rate(clk->hw, rate, &parent_rate, 968 &parent); 969 else if (clk->ops->round_rate) 970 return clk->ops->round_rate(clk->hw, rate, &parent_rate); 971 else if (clk->flags & CLK_SET_RATE_PARENT) 972 return __clk_round_rate(clk->parent, rate); 973 else 974 return clk->rate; 975} 976 977/** 978 * clk_round_rate - round the given rate for a clk 979 * @clk: the clk for which we are rounding a rate 980 * @rate: the rate which is to be rounded 981 * 982 * Takes in a rate as input and rounds it to a rate that the clk can actually 983 * use which is then returned. If clk doesn't support round_rate operation 984 * then the parent rate is returned. 985 */ 986long clk_round_rate(struct clk *clk, unsigned long rate) 987{ 988 unsigned long ret; 989 990 clk_prepare_lock(); 991 ret = __clk_round_rate(clk, rate); 992 clk_prepare_unlock(); 993 994 return ret; 995} 996EXPORT_SYMBOL_GPL(clk_round_rate); 997 998/** 999 * __clk_notify - call clk notifier chain 1000 * @clk: struct clk * that is changing rate 1001 * @msg: clk notifier type (see include/linux/clk.h) 1002 * @old_rate: old clk rate 1003 * @new_rate: new clk rate 1004 * 1005 * Triggers a notifier call chain on the clk rate-change notification 1006 * for 'clk'. Passes a pointer to the struct clk and the previous 1007 * and current rates to the notifier callback. Intended to be called by 1008 * internal clock code only. Returns NOTIFY_DONE from the last driver 1009 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if 1010 * a driver returns that. 1011 */ 1012static int __clk_notify(struct clk *clk, unsigned long msg, 1013 unsigned long old_rate, unsigned long new_rate) 1014{ 1015 struct clk_notifier *cn; 1016 struct clk_notifier_data cnd; 1017 int ret = NOTIFY_DONE; 1018 1019 cnd.clk = clk; 1020 cnd.old_rate = old_rate; 1021 cnd.new_rate = new_rate; 1022 1023 list_for_each_entry(cn, &clk_notifier_list, node) { 1024 if (cn->clk == clk) { 1025 ret = srcu_notifier_call_chain(&cn->notifier_head, msg, 1026 &cnd); 1027 break; 1028 } 1029 } 1030 1031 return ret; 1032} 1033 1034/** 1035 * __clk_recalc_accuracies 1036 * @clk: first clk in the subtree 1037 * 1038 * Walks the subtree of clks starting with clk and recalculates accuracies as 1039 * it goes. Note that if a clk does not implement the .recalc_accuracy 1040 * callback then it is assumed that the clock will take on the accuracy of it's 1041 * parent. 1042 * 1043 * Caller must hold prepare_lock. 1044 */ 1045static void __clk_recalc_accuracies(struct clk *clk) 1046{ 1047 unsigned long parent_accuracy = 0; 1048 struct clk *child; 1049 1050 if (clk->parent) 1051 parent_accuracy = clk->parent->accuracy; 1052 1053 if (clk->ops->recalc_accuracy) 1054 clk->accuracy = clk->ops->recalc_accuracy(clk->hw, 1055 parent_accuracy); 1056 else 1057 clk->accuracy = parent_accuracy; 1058 1059 hlist_for_each_entry(child, &clk->children, child_node) 1060 __clk_recalc_accuracies(child); 1061} 1062 1063/** 1064 * clk_get_accuracy - return the accuracy of clk 1065 * @clk: the clk whose accuracy is being returned 1066 * 1067 * Simply returns the cached accuracy of the clk, unless 1068 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be 1069 * issued. 1070 * If clk is NULL then returns 0. 1071 */ 1072long clk_get_accuracy(struct clk *clk) 1073{ 1074 unsigned long accuracy; 1075 1076 clk_prepare_lock(); 1077 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE)) 1078 __clk_recalc_accuracies(clk); 1079 1080 accuracy = __clk_get_accuracy(clk); 1081 clk_prepare_unlock(); 1082 1083 return accuracy; 1084} 1085EXPORT_SYMBOL_GPL(clk_get_accuracy); 1086 1087/** 1088 * __clk_recalc_rates 1089 * @clk: first clk in the subtree 1090 * @msg: notification type (see include/linux/clk.h) 1091 * 1092 * Walks the subtree of clks starting with clk and recalculates rates as it 1093 * goes. Note that if a clk does not implement the .recalc_rate callback then 1094 * it is assumed that the clock will take on the rate of its parent. 1095 * 1096 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification, 1097 * if necessary. 1098 * 1099 * Caller must hold prepare_lock. 1100 */ 1101static void __clk_recalc_rates(struct clk *clk, unsigned long msg) 1102{ 1103 unsigned long old_rate; 1104 unsigned long parent_rate = 0; 1105 struct clk *child; 1106 1107 old_rate = clk->rate; 1108 1109 if (clk->parent) 1110 parent_rate = clk->parent->rate; 1111 1112 if (clk->ops->recalc_rate) 1113 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate); 1114 else 1115 clk->rate = parent_rate; 1116 1117 /* 1118 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE 1119 * & ABORT_RATE_CHANGE notifiers 1120 */ 1121 if (clk->notifier_count && msg) 1122 __clk_notify(clk, msg, old_rate, clk->rate); 1123 1124 hlist_for_each_entry(child, &clk->children, child_node) 1125 __clk_recalc_rates(child, msg); 1126} 1127 1128/** 1129 * clk_get_rate - return the rate of clk 1130 * @clk: the clk whose rate is being returned 1131 * 1132 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag 1133 * is set, which means a recalc_rate will be issued. 1134 * If clk is NULL then returns 0. 1135 */ 1136unsigned long clk_get_rate(struct clk *clk) 1137{ 1138 unsigned long rate; 1139 1140 clk_prepare_lock(); 1141 1142 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE)) 1143 __clk_recalc_rates(clk, 0); 1144 1145 rate = __clk_get_rate(clk); 1146 clk_prepare_unlock(); 1147 1148 return rate; 1149} 1150EXPORT_SYMBOL_GPL(clk_get_rate); 1151 1152static int clk_fetch_parent_index(struct clk *clk, struct clk *parent) 1153{ 1154 int i; 1155 1156 if (!clk->parents) { 1157 clk->parents = kcalloc(clk->num_parents, 1158 sizeof(struct clk *), GFP_KERNEL); 1159 if (!clk->parents) 1160 return -ENOMEM; 1161 } 1162 1163 /* 1164 * find index of new parent clock using cached parent ptrs, 1165 * or if not yet cached, use string name comparison and cache 1166 * them now to avoid future calls to __clk_lookup. 1167 */ 1168 for (i = 0; i < clk->num_parents; i++) { 1169 if (clk->parents[i] == parent) 1170 return i; 1171 1172 if (clk->parents[i]) 1173 continue; 1174 1175 if (!strcmp(clk->parent_names[i], parent->name)) { 1176 clk->parents[i] = __clk_lookup(parent->name); 1177 return i; 1178 } 1179 } 1180 1181 return -EINVAL; 1182} 1183 1184static void clk_reparent(struct clk *clk, struct clk *new_parent) 1185{ 1186 hlist_del(&clk->child_node); 1187 1188 if (new_parent) { 1189 /* avoid duplicate POST_RATE_CHANGE notifications */ 1190 if (new_parent->new_child == clk) 1191 new_parent->new_child = NULL; 1192 1193 hlist_add_head(&clk->child_node, &new_parent->children); 1194 } else { 1195 hlist_add_head(&clk->child_node, &clk_orphan_list); 1196 } 1197 1198 clk->parent = new_parent; 1199} 1200 1201static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index) 1202{ 1203 unsigned long flags; 1204 int ret = 0; 1205 struct clk *old_parent = clk->parent; 1206 1207 /* 1208 * Migrate prepare state between parents and prevent race with 1209 * clk_enable(). 1210 * 1211 * If the clock is not prepared, then a race with 1212 * clk_enable/disable() is impossible since we already have the 1213 * prepare lock (future calls to clk_enable() need to be preceded by 1214 * a clk_prepare()). 1215 * 1216 * If the clock is prepared, migrate the prepared state to the new 1217 * parent and also protect against a race with clk_enable() by 1218 * forcing the clock and the new parent on. This ensures that all 1219 * future calls to clk_enable() are practically NOPs with respect to 1220 * hardware and software states. 1221 * 1222 * See also: Comment for clk_set_parent() below. 1223 */ 1224 if (clk->prepare_count) { 1225 __clk_prepare(parent); 1226 clk_enable(parent); 1227 clk_enable(clk); 1228 } 1229 1230 /* update the clk tree topology */ 1231 flags = clk_enable_lock(); 1232 clk_reparent(clk, parent); 1233 clk_enable_unlock(flags); 1234 1235 /* change clock input source */ 1236 if (parent && clk->ops->set_parent) 1237 ret = clk->ops->set_parent(clk->hw, p_index); 1238 1239 if (ret) { 1240 flags = clk_enable_lock(); 1241 clk_reparent(clk, old_parent); 1242 clk_enable_unlock(flags); 1243 1244 if (clk->prepare_count) { 1245 clk_disable(clk); 1246 clk_disable(parent); 1247 __clk_unprepare(parent); 1248 } 1249 return ret; 1250 } 1251 1252 /* 1253 * Finish the migration of prepare state and undo the changes done 1254 * for preventing a race with clk_enable(). 1255 */ 1256 if (clk->prepare_count) { 1257 clk_disable(clk); 1258 clk_disable(old_parent); 1259 __clk_unprepare(old_parent); 1260 } 1261 1262 /* update debugfs with new clk tree topology */ 1263 clk_debug_reparent(clk, parent); 1264 return 0; 1265} 1266 1267/** 1268 * __clk_speculate_rates 1269 * @clk: first clk in the subtree 1270 * @parent_rate: the "future" rate of clk's parent 1271 * 1272 * Walks the subtree of clks starting with clk, speculating rates as it 1273 * goes and firing off PRE_RATE_CHANGE notifications as necessary. 1274 * 1275 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending 1276 * pre-rate change notifications and returns early if no clks in the 1277 * subtree have subscribed to the notifications. Note that if a clk does not 1278 * implement the .recalc_rate callback then it is assumed that the clock will 1279 * take on the rate of its parent. 1280 * 1281 * Caller must hold prepare_lock. 1282 */ 1283static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate) 1284{ 1285 struct clk *child; 1286 unsigned long new_rate; 1287 int ret = NOTIFY_DONE; 1288 1289 if (clk->ops->recalc_rate) 1290 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate); 1291 else 1292 new_rate = parent_rate; 1293 1294 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */ 1295 if (clk->notifier_count) 1296 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate); 1297 1298 if (ret & NOTIFY_STOP_MASK) 1299 goto out; 1300 1301 hlist_for_each_entry(child, &clk->children, child_node) { 1302 ret = __clk_speculate_rates(child, new_rate); 1303 if (ret & NOTIFY_STOP_MASK) 1304 break; 1305 } 1306 1307out: 1308 return ret; 1309} 1310 1311static void clk_calc_subtree(struct clk *clk, unsigned long new_rate, 1312 struct clk *new_parent, u8 p_index) 1313{ 1314 struct clk *child; 1315 1316 clk->new_rate = new_rate; 1317 clk->new_parent = new_parent; 1318 clk->new_parent_index = p_index; 1319 /* include clk in new parent's PRE_RATE_CHANGE notifications */ 1320 clk->new_child = NULL; 1321 if (new_parent && new_parent != clk->parent) 1322 new_parent->new_child = clk; 1323 1324 hlist_for_each_entry(child, &clk->children, child_node) { 1325 if (child->ops->recalc_rate) 1326 child->new_rate = child->ops->recalc_rate(child->hw, new_rate); 1327 else 1328 child->new_rate = new_rate; 1329 clk_calc_subtree(child, child->new_rate, NULL, 0); 1330 } 1331} 1332 1333/* 1334 * calculate the new rates returning the topmost clock that has to be 1335 * changed. 1336 */ 1337static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) 1338{ 1339 struct clk *top = clk; 1340 struct clk *old_parent, *parent; 1341 unsigned long best_parent_rate = 0; 1342 unsigned long new_rate; 1343 int p_index = 0; 1344 1345 /* sanity */ 1346 if (IS_ERR_OR_NULL(clk)) 1347 return NULL; 1348 1349 /* save parent rate, if it exists */ 1350 parent = old_parent = clk->parent; 1351 if (parent) 1352 best_parent_rate = parent->rate; 1353 1354 /* find the closest rate and parent clk/rate */ 1355 if (clk->ops->determine_rate) { 1356 new_rate = clk->ops->determine_rate(clk->hw, rate, 1357 &best_parent_rate, 1358 &parent); 1359 } else if (clk->ops->round_rate) { 1360 new_rate = clk->ops->round_rate(clk->hw, rate, 1361 &best_parent_rate); 1362 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) { 1363 /* pass-through clock without adjustable parent */ 1364 clk->new_rate = clk->rate; 1365 return NULL; 1366 } else { 1367 /* pass-through clock with adjustable parent */ 1368 top = clk_calc_new_rates(parent, rate); 1369 new_rate = parent->new_rate; 1370 goto out; 1371 } 1372 1373 /* some clocks must be gated to change parent */ 1374 if (parent != old_parent && 1375 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) { 1376 pr_debug("%s: %s not gated but wants to reparent\n", 1377 __func__, clk->name); 1378 return NULL; 1379 } 1380 1381 /* try finding the new parent index */ 1382 if (parent) { 1383 p_index = clk_fetch_parent_index(clk, parent); 1384 if (p_index < 0) { 1385 pr_debug("%s: clk %s can not be parent of clk %s\n", 1386 __func__, parent->name, clk->name); 1387 return NULL; 1388 } 1389 } 1390 1391 if ((clk->flags & CLK_SET_RATE_PARENT) && parent && 1392 best_parent_rate != parent->rate) 1393 top = clk_calc_new_rates(parent, best_parent_rate); 1394 1395out: 1396 clk_calc_subtree(clk, new_rate, parent, p_index); 1397 1398 return top; 1399} 1400 1401/* 1402 * Notify about rate changes in a subtree. Always walk down the whole tree 1403 * so that in case of an error we can walk down the whole tree again and 1404 * abort the change. 1405 */ 1406static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event) 1407{ 1408 struct clk *child, *tmp_clk, *fail_clk = NULL; 1409 int ret = NOTIFY_DONE; 1410 1411 if (clk->rate == clk->new_rate) 1412 return NULL; 1413 1414 if (clk->notifier_count) { 1415 ret = __clk_notify(clk, event, clk->rate, clk->new_rate); 1416 if (ret & NOTIFY_STOP_MASK) 1417 fail_clk = clk; 1418 } 1419 1420 hlist_for_each_entry(child, &clk->children, child_node) { 1421 /* Skip children who will be reparented to another clock */ 1422 if (child->new_parent && child->new_parent != clk) 1423 continue; 1424 tmp_clk = clk_propagate_rate_change(child, event); 1425 if (tmp_clk) 1426 fail_clk = tmp_clk; 1427 } 1428 1429 /* handle the new child who might not be in clk->children yet */ 1430 if (clk->new_child) { 1431 tmp_clk = clk_propagate_rate_change(clk->new_child, event); 1432 if (tmp_clk) 1433 fail_clk = tmp_clk; 1434 } 1435 1436 return fail_clk; 1437} 1438 1439/* 1440 * walk down a subtree and set the new rates notifying the rate 1441 * change on the way 1442 */ 1443static void clk_change_rate(struct clk *clk) 1444{ 1445 struct clk *child; 1446 unsigned long old_rate; 1447 unsigned long best_parent_rate = 0; 1448 1449 old_rate = clk->rate; 1450 1451 /* set parent */ 1452 if (clk->new_parent && clk->new_parent != clk->parent) 1453 __clk_set_parent(clk, clk->new_parent, clk->new_parent_index); 1454 1455 if (clk->parent) 1456 best_parent_rate = clk->parent->rate; 1457 1458 if (clk->ops->set_rate) 1459 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate); 1460 1461 if (clk->ops->recalc_rate) 1462 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate); 1463 else 1464 clk->rate = best_parent_rate; 1465 1466 if (clk->notifier_count && old_rate != clk->rate) 1467 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); 1468 1469 hlist_for_each_entry(child, &clk->children, child_node) { 1470 /* Skip children who will be reparented to another clock */ 1471 if (child->new_parent && child->new_parent != clk) 1472 continue; 1473 clk_change_rate(child); 1474 } 1475 1476 /* handle the new child who might not be in clk->children yet */ 1477 if (clk->new_child) 1478 clk_change_rate(clk->new_child); 1479} 1480 1481/** 1482 * clk_set_rate - specify a new rate for clk 1483 * @clk: the clk whose rate is being changed 1484 * @rate: the new rate for clk 1485 * 1486 * In the simplest case clk_set_rate will only adjust the rate of clk. 1487 * 1488 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to 1489 * propagate up to clk's parent; whether or not this happens depends on the 1490 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged 1491 * after calling .round_rate then upstream parent propagation is ignored. If 1492 * *parent_rate comes back with a new rate for clk's parent then we propagate 1493 * up to clk's parent and set its rate. Upward propagation will continue 1494 * until either a clk does not support the CLK_SET_RATE_PARENT flag or 1495 * .round_rate stops requesting changes to clk's parent_rate. 1496 * 1497 * Rate changes are accomplished via tree traversal that also recalculates the 1498 * rates for the clocks and fires off POST_RATE_CHANGE notifiers. 1499 * 1500 * Returns 0 on success, -EERROR otherwise. 1501 */ 1502int clk_set_rate(struct clk *clk, unsigned long rate) 1503{ 1504 struct clk *top, *fail_clk; 1505 int ret = 0; 1506 1507 if (!clk) 1508 return 0; 1509 1510 /* prevent racing with updates to the clock topology */ 1511 clk_prepare_lock(); 1512 1513 /* bail early if nothing to do */ 1514 if (rate == clk_get_rate(clk)) 1515 goto out; 1516 1517 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) { 1518 ret = -EBUSY; 1519 goto out; 1520 } 1521 1522 /* calculate new rates and get the topmost changed clock */ 1523 top = clk_calc_new_rates(clk, rate); 1524 if (!top) { 1525 ret = -EINVAL; 1526 goto out; 1527 } 1528 1529 /* notify that we are about to change rates */ 1530 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE); 1531 if (fail_clk) { 1532 pr_warn("%s: failed to set %s rate\n", __func__, 1533 fail_clk->name); 1534 clk_propagate_rate_change(top, ABORT_RATE_CHANGE); 1535 ret = -EBUSY; 1536 goto out; 1537 } 1538 1539 /* change the rates */ 1540 clk_change_rate(top); 1541 1542out: 1543 clk_prepare_unlock(); 1544 1545 return ret; 1546} 1547EXPORT_SYMBOL_GPL(clk_set_rate); 1548 1549/** 1550 * clk_get_parent - return the parent of a clk 1551 * @clk: the clk whose parent gets returned 1552 * 1553 * Simply returns clk->parent. Returns NULL if clk is NULL. 1554 */ 1555struct clk *clk_get_parent(struct clk *clk) 1556{ 1557 struct clk *parent; 1558 1559 clk_prepare_lock(); 1560 parent = __clk_get_parent(clk); 1561 clk_prepare_unlock(); 1562 1563 return parent; 1564} 1565EXPORT_SYMBOL_GPL(clk_get_parent); 1566 1567/* 1568 * .get_parent is mandatory for clocks with multiple possible parents. It is 1569 * optional for single-parent clocks. Always call .get_parent if it is 1570 * available and WARN if it is missing for multi-parent clocks. 1571 * 1572 * For single-parent clocks without .get_parent, first check to see if the 1573 * .parents array exists, and if so use it to avoid an expensive tree 1574 * traversal. If .parents does not exist then walk the tree with __clk_lookup. 1575 */ 1576static struct clk *__clk_init_parent(struct clk *clk) 1577{ 1578 struct clk *ret = NULL; 1579 u8 index; 1580 1581 /* handle the trivial cases */ 1582 1583 if (!clk->num_parents) 1584 goto out; 1585 1586 if (clk->num_parents == 1) { 1587 if (IS_ERR_OR_NULL(clk->parent)) 1588 ret = clk->parent = __clk_lookup(clk->parent_names[0]); 1589 ret = clk->parent; 1590 goto out; 1591 } 1592 1593 if (!clk->ops->get_parent) { 1594 WARN(!clk->ops->get_parent, 1595 "%s: multi-parent clocks must implement .get_parent\n", 1596 __func__); 1597 goto out; 1598 }; 1599 1600 /* 1601 * Do our best to cache parent clocks in clk->parents. This prevents 1602 * unnecessary and expensive calls to __clk_lookup. We don't set 1603 * clk->parent here; that is done by the calling function 1604 */ 1605 1606 index = clk->ops->get_parent(clk->hw); 1607 1608 if (!clk->parents) 1609 clk->parents = 1610 kcalloc(clk->num_parents, sizeof(struct clk *), 1611 GFP_KERNEL); 1612 1613 ret = clk_get_parent_by_index(clk, index); 1614 1615out: 1616 return ret; 1617} 1618 1619void __clk_reparent(struct clk *clk, struct clk *new_parent) 1620{ 1621 clk_reparent(clk, new_parent); 1622 clk_debug_reparent(clk, new_parent); 1623 __clk_recalc_accuracies(clk); 1624 __clk_recalc_rates(clk, POST_RATE_CHANGE); 1625} 1626 1627/** 1628 * clk_set_parent - switch the parent of a mux clk 1629 * @clk: the mux clk whose input we are switching 1630 * @parent: the new input to clk 1631 * 1632 * Re-parent clk to use parent as its new input source. If clk is in 1633 * prepared state, the clk will get enabled for the duration of this call. If 1634 * that's not acceptable for a specific clk (Eg: the consumer can't handle 1635 * that, the reparenting is glitchy in hardware, etc), use the 1636 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared. 1637 * 1638 * After successfully changing clk's parent clk_set_parent will update the 1639 * clk topology, sysfs topology and propagate rate recalculation via 1640 * __clk_recalc_rates. 1641 * 1642 * Returns 0 on success, -EERROR otherwise. 1643 */ 1644int clk_set_parent(struct clk *clk, struct clk *parent) 1645{ 1646 int ret = 0; 1647 int p_index = 0; 1648 unsigned long p_rate = 0; 1649 1650 if (!clk) 1651 return 0; 1652 1653 if (!clk->ops) 1654 return -EINVAL; 1655 1656 /* verify ops for for multi-parent clks */ 1657 if ((clk->num_parents > 1) && (!clk->ops->set_parent)) 1658 return -ENOSYS; 1659 1660 /* prevent racing with updates to the clock topology */ 1661 clk_prepare_lock(); 1662 1663 if (clk->parent == parent) 1664 goto out; 1665 1666 /* check that we are allowed to re-parent if the clock is in use */ 1667 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) { 1668 ret = -EBUSY; 1669 goto out; 1670 } 1671 1672 /* try finding the new parent index */ 1673 if (parent) { 1674 p_index = clk_fetch_parent_index(clk, parent); 1675 p_rate = parent->rate; 1676 if (p_index < 0) { 1677 pr_debug("%s: clk %s can not be parent of clk %s\n", 1678 __func__, parent->name, clk->name); 1679 ret = p_index; 1680 goto out; 1681 } 1682 } 1683 1684 /* propagate PRE_RATE_CHANGE notifications */ 1685 ret = __clk_speculate_rates(clk, p_rate); 1686 1687 /* abort if a driver objects */ 1688 if (ret & NOTIFY_STOP_MASK) 1689 goto out; 1690 1691 /* do the re-parent */ 1692 ret = __clk_set_parent(clk, parent, p_index); 1693 1694 /* propagate rate an accuracy recalculation accordingly */ 1695 if (ret) { 1696 __clk_recalc_rates(clk, ABORT_RATE_CHANGE); 1697 } else { 1698 __clk_recalc_rates(clk, POST_RATE_CHANGE); 1699 __clk_recalc_accuracies(clk); 1700 } 1701 1702out: 1703 clk_prepare_unlock(); 1704 1705 return ret; 1706} 1707EXPORT_SYMBOL_GPL(clk_set_parent); 1708 1709/** 1710 * __clk_init - initialize the data structures in a struct clk 1711 * @dev: device initializing this clk, placeholder for now 1712 * @clk: clk being initialized 1713 * 1714 * Initializes the lists in struct clk, queries the hardware for the 1715 * parent and rate and sets them both. 1716 */ 1717int __clk_init(struct device *dev, struct clk *clk) 1718{ 1719 int i, ret = 0; 1720 struct clk *orphan; 1721 struct hlist_node *tmp2; 1722 1723 if (!clk) 1724 return -EINVAL; 1725 1726 clk_prepare_lock(); 1727 1728 /* check to see if a clock with this name is already registered */ 1729 if (__clk_lookup(clk->name)) { 1730 pr_debug("%s: clk %s already initialized\n", 1731 __func__, clk->name); 1732 ret = -EEXIST; 1733 goto out; 1734 } 1735 1736 /* check that clk_ops are sane. See Documentation/clk.txt */ 1737 if (clk->ops->set_rate && 1738 !((clk->ops->round_rate || clk->ops->determine_rate) && 1739 clk->ops->recalc_rate)) { 1740 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n", 1741 __func__, clk->name); 1742 ret = -EINVAL; 1743 goto out; 1744 } 1745 1746 if (clk->ops->set_parent && !clk->ops->get_parent) { 1747 pr_warning("%s: %s must implement .get_parent & .set_parent\n", 1748 __func__, clk->name); 1749 ret = -EINVAL; 1750 goto out; 1751 } 1752 1753 /* throw a WARN if any entries in parent_names are NULL */ 1754 for (i = 0; i < clk->num_parents; i++) 1755 WARN(!clk->parent_names[i], 1756 "%s: invalid NULL in %s's .parent_names\n", 1757 __func__, clk->name); 1758 1759 /* 1760 * Allocate an array of struct clk *'s to avoid unnecessary string 1761 * look-ups of clk's possible parents. This can fail for clocks passed 1762 * in to clk_init during early boot; thus any access to clk->parents[] 1763 * must always check for a NULL pointer and try to populate it if 1764 * necessary. 1765 * 1766 * If clk->parents is not NULL we skip this entire block. This allows 1767 * for clock drivers to statically initialize clk->parents. 1768 */ 1769 if (clk->num_parents > 1 && !clk->parents) { 1770 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *), 1771 GFP_KERNEL); 1772 /* 1773 * __clk_lookup returns NULL for parents that have not been 1774 * clk_init'd; thus any access to clk->parents[] must check 1775 * for a NULL pointer. We can always perform lazy lookups for 1776 * missing parents later on. 1777 */ 1778 if (clk->parents) 1779 for (i = 0; i < clk->num_parents; i++) 1780 clk->parents[i] = 1781 __clk_lookup(clk->parent_names[i]); 1782 } 1783 1784 clk->parent = __clk_init_parent(clk); 1785 1786 /* 1787 * Populate clk->parent if parent has already been __clk_init'd. If 1788 * parent has not yet been __clk_init'd then place clk in the orphan 1789 * list. If clk has set the CLK_IS_ROOT flag then place it in the root 1790 * clk list. 1791 * 1792 * Every time a new clk is clk_init'd then we walk the list of orphan 1793 * clocks and re-parent any that are children of the clock currently 1794 * being clk_init'd. 1795 */ 1796 if (clk->parent) 1797 hlist_add_head(&clk->child_node, 1798 &clk->parent->children); 1799 else if (clk->flags & CLK_IS_ROOT) 1800 hlist_add_head(&clk->child_node, &clk_root_list); 1801 else 1802 hlist_add_head(&clk->child_node, &clk_orphan_list); 1803 1804 /* 1805 * Set clk's accuracy. The preferred method is to use 1806 * .recalc_accuracy. For simple clocks and lazy developers the default 1807 * fallback is to use the parent's accuracy. If a clock doesn't have a 1808 * parent (or is orphaned) then accuracy is set to zero (perfect 1809 * clock). 1810 */ 1811 if (clk->ops->recalc_accuracy) 1812 clk->accuracy = clk->ops->recalc_accuracy(clk->hw, 1813 __clk_get_accuracy(clk->parent)); 1814 else if (clk->parent) 1815 clk->accuracy = clk->parent->accuracy; 1816 else 1817 clk->accuracy = 0; 1818 1819 /* 1820 * Set clk's rate. The preferred method is to use .recalc_rate. For 1821 * simple clocks and lazy developers the default fallback is to use the 1822 * parent's rate. If a clock doesn't have a parent (or is orphaned) 1823 * then rate is set to zero. 1824 */ 1825 if (clk->ops->recalc_rate) 1826 clk->rate = clk->ops->recalc_rate(clk->hw, 1827 __clk_get_rate(clk->parent)); 1828 else if (clk->parent) 1829 clk->rate = clk->parent->rate; 1830 else 1831 clk->rate = 0; 1832 1833 clk_debug_register(clk); 1834 /* 1835 * walk the list of orphan clocks and reparent any that are children of 1836 * this clock 1837 */ 1838 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { 1839 if (orphan->num_parents && orphan->ops->get_parent) { 1840 i = orphan->ops->get_parent(orphan->hw); 1841 if (!strcmp(clk->name, orphan->parent_names[i])) 1842 __clk_reparent(orphan, clk); 1843 continue; 1844 } 1845 1846 for (i = 0; i < orphan->num_parents; i++) 1847 if (!strcmp(clk->name, orphan->parent_names[i])) { 1848 __clk_reparent(orphan, clk); 1849 break; 1850 } 1851 } 1852 1853 /* 1854 * optional platform-specific magic 1855 * 1856 * The .init callback is not used by any of the basic clock types, but 1857 * exists for weird hardware that must perform initialization magic. 1858 * Please consider other ways of solving initialization problems before 1859 * using this callback, as its use is discouraged. 1860 */ 1861 if (clk->ops->init) 1862 clk->ops->init(clk->hw); 1863 1864out: 1865 clk_prepare_unlock(); 1866 1867 return ret; 1868} 1869 1870/** 1871 * __clk_register - register a clock and return a cookie. 1872 * 1873 * Same as clk_register, except that the .clk field inside hw shall point to a 1874 * preallocated (generally statically allocated) struct clk. None of the fields 1875 * of the struct clk need to be initialized. 1876 * 1877 * The data pointed to by .init and .clk field shall NOT be marked as init 1878 * data. 1879 * 1880 * __clk_register is only exposed via clk-private.h and is intended for use with 1881 * very large numbers of clocks that need to be statically initialized. It is 1882 * a layering violation to include clk-private.h from any code which implements 1883 * a clock's .ops; as such any statically initialized clock data MUST be in a 1884 * separate C file from the logic that implements its operations. Returns 0 1885 * on success, otherwise an error code. 1886 */ 1887struct clk *__clk_register(struct device *dev, struct clk_hw *hw) 1888{ 1889 int ret; 1890 struct clk *clk; 1891 1892 clk = hw->clk; 1893 clk->name = hw->init->name; 1894 clk->ops = hw->init->ops; 1895 clk->hw = hw; 1896 clk->flags = hw->init->flags; 1897 clk->parent_names = hw->init->parent_names; 1898 clk->num_parents = hw->init->num_parents; 1899 1900 ret = __clk_init(dev, clk); 1901 if (ret) 1902 return ERR_PTR(ret); 1903 1904 return clk; 1905} 1906EXPORT_SYMBOL_GPL(__clk_register); 1907 1908static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk) 1909{ 1910 int i, ret; 1911 1912 clk->name = kstrdup(hw->init->name, GFP_KERNEL); 1913 if (!clk->name) { 1914 pr_err("%s: could not allocate clk->name\n", __func__); 1915 ret = -ENOMEM; 1916 goto fail_name; 1917 } 1918 clk->ops = hw->init->ops; 1919 clk->hw = hw; 1920 clk->flags = hw->init->flags; 1921 clk->num_parents = hw->init->num_parents; 1922 hw->clk = clk; 1923 1924 /* allocate local copy in case parent_names is __initdata */ 1925 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *), 1926 GFP_KERNEL); 1927 1928 if (!clk->parent_names) { 1929 pr_err("%s: could not allocate clk->parent_names\n", __func__); 1930 ret = -ENOMEM; 1931 goto fail_parent_names; 1932 } 1933 1934 1935 /* copy each string name in case parent_names is __initdata */ 1936 for (i = 0; i < clk->num_parents; i++) { 1937 clk->parent_names[i] = kstrdup(hw->init->parent_names[i], 1938 GFP_KERNEL); 1939 if (!clk->parent_names[i]) { 1940 pr_err("%s: could not copy parent_names\n", __func__); 1941 ret = -ENOMEM; 1942 goto fail_parent_names_copy; 1943 } 1944 } 1945 1946 ret = __clk_init(dev, clk); 1947 if (!ret) 1948 return 0; 1949 1950fail_parent_names_copy: 1951 while (--i >= 0) 1952 kfree(clk->parent_names[i]); 1953 kfree(clk->parent_names); 1954fail_parent_names: 1955 kfree(clk->name); 1956fail_name: 1957 return ret; 1958} 1959 1960/** 1961 * clk_register - allocate a new clock, register it and return an opaque cookie 1962 * @dev: device that is registering this clock 1963 * @hw: link to hardware-specific clock data 1964 * 1965 * clk_register is the primary interface for populating the clock tree with new 1966 * clock nodes. It returns a pointer to the newly allocated struct clk which 1967 * cannot be dereferenced by driver code but may be used in conjuction with the 1968 * rest of the clock API. In the event of an error clk_register will return an 1969 * error code; drivers must test for an error code after calling clk_register. 1970 */ 1971struct clk *clk_register(struct device *dev, struct clk_hw *hw) 1972{ 1973 int ret; 1974 struct clk *clk; 1975 1976 clk = kzalloc(sizeof(*clk), GFP_KERNEL); 1977 if (!clk) { 1978 pr_err("%s: could not allocate clk\n", __func__); 1979 ret = -ENOMEM; 1980 goto fail_out; 1981 } 1982 1983 ret = _clk_register(dev, hw, clk); 1984 if (!ret) 1985 return clk; 1986 1987 kfree(clk); 1988fail_out: 1989 return ERR_PTR(ret); 1990} 1991EXPORT_SYMBOL_GPL(clk_register); 1992 1993/** 1994 * clk_unregister - unregister a currently registered clock 1995 * @clk: clock to unregister 1996 * 1997 * Currently unimplemented. 1998 */ 1999void clk_unregister(struct clk *clk) {} 2000EXPORT_SYMBOL_GPL(clk_unregister); 2001 2002static void devm_clk_release(struct device *dev, void *res) 2003{ 2004 clk_unregister(res); 2005} 2006 2007/** 2008 * devm_clk_register - resource managed clk_register() 2009 * @dev: device that is registering this clock 2010 * @hw: link to hardware-specific clock data 2011 * 2012 * Managed clk_register(). Clocks returned from this function are 2013 * automatically clk_unregister()ed on driver detach. See clk_register() for 2014 * more information. 2015 */ 2016struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw) 2017{ 2018 struct clk *clk; 2019 int ret; 2020 2021 clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL); 2022 if (!clk) 2023 return ERR_PTR(-ENOMEM); 2024 2025 ret = _clk_register(dev, hw, clk); 2026 if (!ret) { 2027 devres_add(dev, clk); 2028 } else { 2029 devres_free(clk); 2030 clk = ERR_PTR(ret); 2031 } 2032 2033 return clk; 2034} 2035EXPORT_SYMBOL_GPL(devm_clk_register); 2036 2037static int devm_clk_match(struct device *dev, void *res, void *data) 2038{ 2039 struct clk *c = res; 2040 if (WARN_ON(!c)) 2041 return 0; 2042 return c == data; 2043} 2044 2045/** 2046 * devm_clk_unregister - resource managed clk_unregister() 2047 * @clk: clock to unregister 2048 * 2049 * Deallocate a clock allocated with devm_clk_register(). Normally 2050 * this function will not need to be called and the resource management 2051 * code will ensure that the resource is freed. 2052 */ 2053void devm_clk_unregister(struct device *dev, struct clk *clk) 2054{ 2055 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk)); 2056} 2057EXPORT_SYMBOL_GPL(devm_clk_unregister); 2058 2059/*** clk rate change notifiers ***/ 2060 2061/** 2062 * clk_notifier_register - add a clk rate change notifier 2063 * @clk: struct clk * to watch 2064 * @nb: struct notifier_block * with callback info 2065 * 2066 * Request notification when clk's rate changes. This uses an SRCU 2067 * notifier because we want it to block and notifier unregistrations are 2068 * uncommon. The callbacks associated with the notifier must not 2069 * re-enter into the clk framework by calling any top-level clk APIs; 2070 * this will cause a nested prepare_lock mutex. 2071 * 2072 * Pre-change notifier callbacks will be passed the current, pre-change 2073 * rate of the clk via struct clk_notifier_data.old_rate. The new, 2074 * post-change rate of the clk is passed via struct 2075 * clk_notifier_data.new_rate. 2076 * 2077 * Post-change notifiers will pass the now-current, post-change rate of 2078 * the clk in both struct clk_notifier_data.old_rate and struct 2079 * clk_notifier_data.new_rate. 2080 * 2081 * Abort-change notifiers are effectively the opposite of pre-change 2082 * notifiers: the original pre-change clk rate is passed in via struct 2083 * clk_notifier_data.new_rate and the failed post-change rate is passed 2084 * in via struct clk_notifier_data.old_rate. 2085 * 2086 * clk_notifier_register() must be called from non-atomic context. 2087 * Returns -EINVAL if called with null arguments, -ENOMEM upon 2088 * allocation failure; otherwise, passes along the return value of 2089 * srcu_notifier_chain_register(). 2090 */ 2091int clk_notifier_register(struct clk *clk, struct notifier_block *nb) 2092{ 2093 struct clk_notifier *cn; 2094 int ret = -ENOMEM; 2095 2096 if (!clk || !nb) 2097 return -EINVAL; 2098 2099 clk_prepare_lock(); 2100 2101 /* search the list of notifiers for this clk */ 2102 list_for_each_entry(cn, &clk_notifier_list, node) 2103 if (cn->clk == clk) 2104 break; 2105 2106 /* if clk wasn't in the notifier list, allocate new clk_notifier */ 2107 if (cn->clk != clk) { 2108 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL); 2109 if (!cn) 2110 goto out; 2111 2112 cn->clk = clk; 2113 srcu_init_notifier_head(&cn->notifier_head); 2114 2115 list_add(&cn->node, &clk_notifier_list); 2116 } 2117 2118 ret = srcu_notifier_chain_register(&cn->notifier_head, nb); 2119 2120 clk->notifier_count++; 2121 2122out: 2123 clk_prepare_unlock(); 2124 2125 return ret; 2126} 2127EXPORT_SYMBOL_GPL(clk_notifier_register); 2128 2129/** 2130 * clk_notifier_unregister - remove a clk rate change notifier 2131 * @clk: struct clk * 2132 * @nb: struct notifier_block * with callback info 2133 * 2134 * Request no further notification for changes to 'clk' and frees memory 2135 * allocated in clk_notifier_register. 2136 * 2137 * Returns -EINVAL if called with null arguments; otherwise, passes 2138 * along the return value of srcu_notifier_chain_unregister(). 2139 */ 2140int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) 2141{ 2142 struct clk_notifier *cn = NULL; 2143 int ret = -EINVAL; 2144 2145 if (!clk || !nb) 2146 return -EINVAL; 2147 2148 clk_prepare_lock(); 2149 2150 list_for_each_entry(cn, &clk_notifier_list, node) 2151 if (cn->clk == clk) 2152 break; 2153 2154 if (cn->clk == clk) { 2155 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); 2156 2157 clk->notifier_count--; 2158 2159 /* XXX the notifier code should handle this better */ 2160 if (!cn->notifier_head.head) { 2161 srcu_cleanup_notifier_head(&cn->notifier_head); 2162 list_del(&cn->node); 2163 kfree(cn); 2164 } 2165 2166 } else { 2167 ret = -ENOENT; 2168 } 2169 2170 clk_prepare_unlock(); 2171 2172 return ret; 2173} 2174EXPORT_SYMBOL_GPL(clk_notifier_unregister); 2175 2176#ifdef CONFIG_OF 2177/** 2178 * struct of_clk_provider - Clock provider registration structure 2179 * @link: Entry in global list of clock providers 2180 * @node: Pointer to device tree node of clock provider 2181 * @get: Get clock callback. Returns NULL or a struct clk for the 2182 * given clock specifier 2183 * @data: context pointer to be passed into @get callback 2184 */ 2185struct of_clk_provider { 2186 struct list_head link; 2187 2188 struct device_node *node; 2189 struct clk *(*get)(struct of_phandle_args *clkspec, void *data); 2190 void *data; 2191}; 2192 2193extern struct of_device_id __clk_of_table[]; 2194 2195static const struct of_device_id __clk_of_table_sentinel 2196 __used __section(__clk_of_table_end); 2197 2198static LIST_HEAD(of_clk_providers); 2199static DEFINE_MUTEX(of_clk_lock); 2200 2201struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec, 2202 void *data) 2203{ 2204 return data; 2205} 2206EXPORT_SYMBOL_GPL(of_clk_src_simple_get); 2207 2208struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data) 2209{ 2210 struct clk_onecell_data *clk_data = data; 2211 unsigned int idx = clkspec->args[0]; 2212 2213 if (idx >= clk_data->clk_num) { 2214 pr_err("%s: invalid clock index %d\n", __func__, idx); 2215 return ERR_PTR(-EINVAL); 2216 } 2217 2218 return clk_data->clks[idx]; 2219} 2220EXPORT_SYMBOL_GPL(of_clk_src_onecell_get); 2221 2222/** 2223 * of_clk_add_provider() - Register a clock provider for a node 2224 * @np: Device node pointer associated with clock provider 2225 * @clk_src_get: callback for decoding clock 2226 * @data: context pointer for @clk_src_get callback. 2227 */ 2228int of_clk_add_provider(struct device_node *np, 2229 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec, 2230 void *data), 2231 void *data) 2232{ 2233 struct of_clk_provider *cp; 2234 2235 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL); 2236 if (!cp) 2237 return -ENOMEM; 2238 2239 cp->node = of_node_get(np); 2240 cp->data = data; 2241 cp->get = clk_src_get; 2242 2243 mutex_lock(&of_clk_lock); 2244 list_add(&cp->link, &of_clk_providers); 2245 mutex_unlock(&of_clk_lock); 2246 pr_debug("Added clock from %s\n", np->full_name); 2247 2248 return 0; 2249} 2250EXPORT_SYMBOL_GPL(of_clk_add_provider); 2251 2252/** 2253 * of_clk_del_provider() - Remove a previously registered clock provider 2254 * @np: Device node pointer associated with clock provider 2255 */ 2256void of_clk_del_provider(struct device_node *np) 2257{ 2258 struct of_clk_provider *cp; 2259 2260 mutex_lock(&of_clk_lock); 2261 list_for_each_entry(cp, &of_clk_providers, link) { 2262 if (cp->node == np) { 2263 list_del(&cp->link); 2264 of_node_put(cp->node); 2265 kfree(cp); 2266 break; 2267 } 2268 } 2269 mutex_unlock(&of_clk_lock); 2270} 2271EXPORT_SYMBOL_GPL(of_clk_del_provider); 2272 2273struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) 2274{ 2275 struct of_clk_provider *provider; 2276 struct clk *clk = ERR_PTR(-ENOENT); 2277 2278 /* Check if we have such a provider in our array */ 2279 mutex_lock(&of_clk_lock); 2280 list_for_each_entry(provider, &of_clk_providers, link) { 2281 if (provider->node == clkspec->np) 2282 clk = provider->get(clkspec, provider->data); 2283 if (!IS_ERR(clk)) 2284 break; 2285 } 2286 mutex_unlock(&of_clk_lock); 2287 2288 return clk; 2289} 2290 2291int of_clk_get_parent_count(struct device_node *np) 2292{ 2293 return of_count_phandle_with_args(np, "clocks", "#clock-cells"); 2294} 2295EXPORT_SYMBOL_GPL(of_clk_get_parent_count); 2296 2297const char *of_clk_get_parent_name(struct device_node *np, int index) 2298{ 2299 struct of_phandle_args clkspec; 2300 const char *clk_name; 2301 int rc; 2302 2303 if (index < 0) 2304 return NULL; 2305 2306 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, 2307 &clkspec); 2308 if (rc) 2309 return NULL; 2310 2311 if (of_property_read_string_index(clkspec.np, "clock-output-names", 2312 clkspec.args_count ? clkspec.args[0] : 0, 2313 &clk_name) < 0) 2314 clk_name = clkspec.np->name; 2315 2316 of_node_put(clkspec.np); 2317 return clk_name; 2318} 2319EXPORT_SYMBOL_GPL(of_clk_get_parent_name); 2320 2321/** 2322 * of_clk_init() - Scan and init clock providers from the DT 2323 * @matches: array of compatible values and init functions for providers. 2324 * 2325 * This function scans the device tree for matching clock providers and 2326 * calls their initialization functions 2327 */ 2328void __init of_clk_init(const struct of_device_id *matches) 2329{ 2330 const struct of_device_id *match; 2331 struct device_node *np; 2332 2333 if (!matches) 2334 matches = __clk_of_table; 2335 2336 for_each_matching_node_and_match(np, matches, &match) { 2337 of_clk_init_cb_t clk_init_cb = match->data; 2338 clk_init_cb(np); 2339 } 2340} 2341#endif 2342