drivers/sh/clk/core.c

   1 /*
   2  * SuperH clock framework
   3  *
   4  *  Copyright (C) 2005 - 2010  Paul Mundt
   5  *
   6  * This clock framework is derived from the OMAP version by:
   7  *
   8  *      Copyright (C) 2004 - 2008 Nokia Corporation
   9  *      Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
  10  *
  11  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
  12  *
  13  * This file is subject to the terms and conditions of the GNU General Public
  14  * License.  See the file "COPYING" in the main directory of this archive
  15  * for more details.
  16  */
  17 #define pr_fmt(fmt) "clock: " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/module.h>
  22 #include <linux/mutex.h>
  23 #include <linux/list.h>
  24 #include <linux/kobject.h>
  25 #include <linux/sysdev.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/err.h>
  28 #include <linux/io.h>
  29 #include <linux/debugfs.h>
  30 #include <linux/cpufreq.h>
  31 #include <linux/clk.h>
  32 #include <linux/sh_clk.h>
  33
  34 static LIST_HEAD(clock_list);
  35 static DEFINE_SPINLOCK(clock_lock);
  36 static DEFINE_MUTEX(clock_list_sem);
  37
  38 void clk_rate_table_build(struct clk *clk,
  39                           struct cpufreq_frequency_table *freq_table,
  40                           int nr_freqs,
  41                           struct clk_div_mult_table *src_table,
  42                           unsigned long *bitmap)
  43 {
  44         unsigned long mult, div;
  45         unsigned long freq;
  46         int i;
  47
  48         clk->nr_freqs = nr_freqs;
  49
  50         for (i = 0; i < nr_freqs; i++) {
  51                 div = 1;
  52                 mult = 1;
  53
  54                 if (src_table->divisors && i < src_table->nr_divisors)
  55                         div = src_table->divisors[i];
  56
  57                 if (src_table->multipliers && i < src_table->nr_multipliers)
  58                         mult = src_table->multipliers[i];
  59
  60                 if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
  61                         freq = CPUFREQ_ENTRY_INVALID;
  62                 else
  63                         freq = clk->parent->rate * mult / div;
  64
  65                 freq_table[i].index = i;
  66                 freq_table[i].frequency = freq;
  67         }
  68
  69         /* Termination entry */
  70         freq_table[i].index = i;
  71         freq_table[i].frequency = CPUFREQ_TABLE_END;
  72 }
  73
  74 struct clk_rate_round_data;
  75
  76 struct clk_rate_round_data {
  77         unsigned long rate;
  78         unsigned int min, max;
  79         long (*func)(unsigned int, struct clk_rate_round_data *);
  80         void *arg;
  81 };
  82
  83 #define for_each_frequency(pos, r, freq)                        \
  84         for (pos = r->min, freq = r->func(pos, r);              \
  85              pos <= r->max; pos++, freq = r->func(pos, r))      \
  86                 if (unlikely(freq == 0))                        \
  87                         ;                                       \
  88                 else
  89
  90 static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
  91 {
  92         unsigned long rate_error, rate_error_prev = ~0UL;
  93         unsigned long highest, lowest, freq;
  94         long rate_best_fit = -ENOENT;
  95         int i;
  96
  97         highest = 0;
  98         lowest = ~0UL;
  99
 100         for_each_frequency(i, rounder, freq) {
 101                 if (freq > highest)
 102                         highest = freq;
 103                 if (freq < lowest)
 104                         lowest = freq;
 105
 106                 rate_error = abs(freq - rounder->rate);
 107                 if (rate_error < rate_error_prev) {
 108                         rate_best_fit = freq;
 109                         rate_error_prev = rate_error;
 110                 }
 111
 112                 if (rate_error == 0)
 113                         break;
 114         }
 115
 116         if (rounder->rate >= highest)
 117                 rate_best_fit = highest;
 118         if (rounder->rate <= lowest)
 119                 rate_best_fit = lowest;
 120
 121         return rate_best_fit;
 122 }
 123
 124 static long clk_rate_table_iter(unsigned int pos,
 125                                 struct clk_rate_round_data *rounder)
 126 {
 127         struct cpufreq_frequency_table *freq_table = rounder->arg;
 128         unsigned long freq = freq_table[pos].frequency;
 129
 130         if (freq == CPUFREQ_ENTRY_INVALID)
 131                 freq = 0;
 132
 133         return freq;
 134 }
 135
 136 long clk_rate_table_round(struct clk *clk,
 137                           struct cpufreq_frequency_table *freq_table,
 138                           unsigned long rate)
 139 {
 140         struct clk_rate_round_data table_round = {
 141                 .min    = 0,
 142                 .max    = clk->nr_freqs - 1,
 143                 .func   = clk_rate_table_iter,
 144                 .arg    = freq_table,
 145                 .rate   = rate,
 146         };
 147
 148         if (clk->nr_freqs < 1)
 149                 return -ENOSYS;
 150
 151         return clk_rate_round_helper(&table_round);
 152 }
 153
 154 static long clk_rate_div_range_iter(unsigned int pos,
 155                                     struct clk_rate_round_data *rounder)
 156 {
 157         return clk_get_rate(rounder->arg) / pos;
 158 }
 159
 160 long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
 161                               unsigned int div_max, unsigned long rate)
 162 {
 163         struct clk_rate_round_data div_range_round = {
 164                 .min    = div_min,
 165                 .max    = div_max,
 166                 .func   = clk_rate_div_range_iter,
 167                 .arg    = clk_get_parent(clk),
 168                 .rate   = rate,
 169         };
 170
 171         return clk_rate_round_helper(&div_range_round);
 172 }
 173
 174 int clk_rate_table_find(struct clk *clk,
 175                         struct cpufreq_frequency_table *freq_table,
 176                         unsigned long rate)
 177 {
 178         int i;
 179
 180         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 181                 unsigned long freq = freq_table[i].frequency;
 182
 183                 if (freq == CPUFREQ_ENTRY_INVALID)
 184                         continue;
 185
 186                 if (freq == rate)
 187                         return i;
 188         }
 189
 190         return -ENOENT;
 191 }
 192
 193 /* Used for clocks that always have same value as the parent clock */
 194 unsigned long followparent_recalc(struct clk *clk)
 195 {
 196         return clk->parent ? clk->parent->rate : 0;
 197 }
 198
 199 int clk_reparent(struct clk *child, struct clk *parent)
 200 {
 201         list_del_init(&child->sibling);
 202         if (parent)
 203                 list_add(&child->sibling, &parent->children);
 204         child->parent = parent;
 205
 206         /* now do the debugfs renaming to reattach the child
 207            to the proper parent */
 208
 209         return 0;
 210 }
 211
 212 /* Propagate rate to children */
 213 void propagate_rate(struct clk *tclk)
 214 {
 215         struct clk *clkp;
 216
 217         list_for_each_entry(clkp, &tclk->children, sibling) {
 218                 if (clkp->ops && clkp->ops->recalc)
 219                         clkp->rate = clkp->ops->recalc(clkp);
 220
 221                 propagate_rate(clkp);
 222         }
 223 }
 224
 225 static void __clk_disable(struct clk *clk)
 226 {
 227         if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
 228                  clk))
 229                 return;
 230
 231         if (!(--clk->usecount)) {
 232                 if (likely(clk->ops && clk->ops->disable))
 233                         clk->ops->disable(clk);
 234                 if (likely(clk->parent))
 235                         __clk_disable(clk->parent);
 236         }
 237 }
 238
 239 void clk_disable(struct clk *clk)
 240 {
 241         unsigned long flags;
 242
 243         if (!clk)
 244                 return;
 245
 246         spin_lock_irqsave(&clock_lock, flags);
 247         __clk_disable(clk);
 248         spin_unlock_irqrestore(&clock_lock, flags);
 249 }
 250 EXPORT_SYMBOL_GPL(clk_disable);
 251
 252 static int __clk_enable(struct clk *clk)
 253 {
 254         int ret = 0;
 255
 256         if (clk->usecount++ == 0) {
 257                 if (clk->parent) {
 258                         ret = __clk_enable(clk->parent);
 259                         if (unlikely(ret))
 260                                 goto err;
 261                 }
 262
 263                 if (clk->ops && clk->ops->enable) {
 264                         ret = clk->ops->enable(clk);
 265                         if (ret) {
 266                                 if (clk->parent)
 267                                         __clk_disable(clk->parent);
 268                                 goto err;
 269                         }
 270                 }
 271         }
 272
 273         return ret;
 274 err:
 275         clk->usecount--;
 276         return ret;
 277 }
 278
 279 int clk_enable(struct clk *clk)
 280 {
 281         unsigned long flags;
 282         int ret;
 283
 284         if (!clk)
 285                 return -EINVAL;
 286
 287         spin_lock_irqsave(&clock_lock, flags);
 288         ret = __clk_enable(clk);
 289         spin_unlock_irqrestore(&clock_lock, flags);
 290
 291         return ret;
 292 }
 293 EXPORT_SYMBOL_GPL(clk_enable);
 294
 295 static LIST_HEAD(root_clks);
 296
 297 /**
 298  * recalculate_root_clocks - recalculate and propagate all root clocks
 299  *
 300  * Recalculates all root clocks (clocks with no parent), which if the
 301  * clock's .recalc is set correctly, should also propagate their rates.
 302  * Called at init.
 303  */
 304 void recalculate_root_clocks(void)
 305 {
 306         struct clk *clkp;
 307
 308         list_for_each_entry(clkp, &root_clks, sibling) {
 309                 if (clkp->ops && clkp->ops->recalc)
 310                         clkp->rate = clkp->ops->recalc(clkp);
 311                 propagate_rate(clkp);
 312         }
 313 }
 314
 315 static struct clk_mapping dummy_mapping;
 316
 317 static struct clk *lookup_root_clock(struct clk *clk)
 318 {
 319         while (clk->parent)
 320                 clk = clk->parent;
 321
 322         return clk;
 323 }
 324
 325 static int clk_establish_mapping(struct clk *clk)
 326 {
 327         struct clk_mapping *mapping = clk->mapping;
 328
 329         /*
 330          * Propagate mappings.
 331          */
 332         if (!mapping) {
 333                 struct clk *clkp;
 334
 335                 /*
 336                  * dummy mapping for root clocks with no specified ranges
 337                  */
 338                 if (!clk->parent) {
 339                         clk->mapping = &dummy_mapping;
 340                         return 0;
 341                 }
 342
 343                 /*
 344                  * If we're on a child clock and it provides no mapping of its
 345                  * own, inherit the mapping from its root clock.
 346                  */
 347                 clkp = lookup_root_clock(clk);
 348                 mapping = clkp->mapping;
 349                 BUG_ON(!mapping);
 350         }
 351
 352         /*
 353          * Establish initial mapping.
 354          */
 355         if (!mapping->base && mapping->phys) {
 356                 kref_init(&mapping->ref);
 357
 358                 mapping->base = ioremap_nocache(mapping->phys, mapping->len);
 359                 if (unlikely(!mapping->base))
 360                         return -ENXIO;
 361         } else if (mapping->base) {
 362                 /*
 363                  * Bump the refcount for an existing mapping
 364                  */
 365                 kref_get(&mapping->ref);
 366         }
 367
 368         clk->mapping = mapping;
 369         return 0;
 370 }
 371
 372 static void clk_destroy_mapping(struct kref *kref)
 373 {
 374         struct clk_mapping *mapping;
 375
 376         mapping = container_of(kref, struct clk_mapping, ref);
 377
 378         iounmap(mapping->base);
 379 }
 380
 381 static void clk_teardown_mapping(struct clk *clk)
 382 {
 383         struct clk_mapping *mapping = clk->mapping;
 384
 385         /* Nothing to do */
 386         if (mapping == &dummy_mapping)
 387                 return;
 388
 389         kref_put(&mapping->ref, clk_destroy_mapping);
 390         clk->mapping = NULL;
 391 }
 392
 393 int clk_register(struct clk *clk)
 394 {
 395         int ret;
 396
 397         if (clk == NULL || IS_ERR(clk))
 398                 return -EINVAL;
 399
 400         /*
 401          * trap out already registered clocks
 402          */
 403         if (clk->node.next || clk->node.prev)
 404                 return 0;
 405
 406         mutex_lock(&clock_list_sem);
 407
 408         INIT_LIST_HEAD(&clk->children);
 409         clk->usecount = 0;
 410
 411         ret = clk_establish_mapping(clk);
 412         if (unlikely(ret))
 413                 goto out_unlock;
 414
 415         if (clk->parent)
 416                 list_add(&clk->sibling, &clk->parent->children);
 417         else
 418                 list_add(&clk->sibling, &root_clks);
 419
 420         list_add(&clk->node, &clock_list);
 421         if (clk->ops && clk->ops->init)
 422                 clk->ops->init(clk);
 423
 424 out_unlock:
 425         mutex_unlock(&clock_list_sem);
 426
 427         return ret;
 428 }
 429 EXPORT_SYMBOL_GPL(clk_register);
 430
 431 void clk_unregister(struct clk *clk)
 432 {
 433         mutex_lock(&clock_list_sem);
 434         list_del(&clk->sibling);
 435         list_del(&clk->node);
 436         clk_teardown_mapping(clk);
 437         mutex_unlock(&clock_list_sem);
 438 }
 439 EXPORT_SYMBOL_GPL(clk_unregister);
 440
 441 void clk_enable_init_clocks(void)
 442 {
 443         struct clk *clkp;
 444
 445         list_for_each_entry(clkp, &clock_list, node)
 446                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 447                         clk_enable(clkp);
 448 }
 449
 450 unsigned long clk_get_rate(struct clk *clk)
 451 {
 452         return clk->rate;
 453 }
 454 EXPORT_SYMBOL_GPL(clk_get_rate);
 455
 456 int clk_set_rate(struct clk *clk, unsigned long rate)
 457 {
 458         return clk_set_rate_ex(clk, rate, 0);
 459 }
 460 EXPORT_SYMBOL_GPL(clk_set_rate);
 461
 462 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 463 {
 464         int ret = -EOPNOTSUPP;
 465         unsigned long flags;
 466
 467         spin_lock_irqsave(&clock_lock, flags);
 468
 469         if (likely(clk->ops && clk->ops->set_rate)) {
 470                 ret = clk->ops->set_rate(clk, rate, algo_id);
 471                 if (ret != 0)
 472                         goto out_unlock;
 473         } else {
 474                 clk->rate = rate;
 475                 ret = 0;
 476         }
 477
 478         if (clk->ops && clk->ops->recalc)
 479                 clk->rate = clk->ops->recalc(clk);
 480
 481         propagate_rate(clk);
 482
 483 out_unlock:
 484         spin_unlock_irqrestore(&clock_lock, flags);
 485
 486         return ret;
 487 }
 488 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 489
 490 int clk_set_parent(struct clk *clk, struct clk *parent)
 491 {
 492         unsigned long flags;
 493         int ret = -EINVAL;
 494
 495         if (!parent || !clk)
 496                 return ret;
 497         if (clk->parent == parent)
 498                 return 0;
 499
 500         spin_lock_irqsave(&clock_lock, flags);
 501         if (clk->usecount == 0) {
 502                 if (clk->ops->set_parent)
 503                         ret = clk->ops->set_parent(clk, parent);
 504                 else
 505                         ret = clk_reparent(clk, parent);
 506
 507                 if (ret == 0) {
 508                         if (clk->ops->recalc)
 509                                 clk->rate = clk->ops->recalc(clk);
 510                         pr_debug("set parent of %p to %p (new rate %ld)\n",
 511                                  clk, clk->parent, clk->rate);
 512                         propagate_rate(clk);
 513                 }
 514         } else
 515                 ret = -EBUSY;
 516         spin_unlock_irqrestore(&clock_lock, flags);
 517
 518         return ret;
 519 }
 520 EXPORT_SYMBOL_GPL(clk_set_parent);
 521
 522 struct clk *clk_get_parent(struct clk *clk)
 523 {
 524         return clk->parent;
 525 }
 526 EXPORT_SYMBOL_GPL(clk_get_parent);
 527
 528 long clk_round_rate(struct clk *clk, unsigned long rate)
 529 {
 530         if (likely(clk->ops && clk->ops->round_rate)) {
 531                 unsigned long flags, rounded;
 532
 533                 spin_lock_irqsave(&clock_lock, flags);
 534                 rounded = clk->ops->round_rate(clk, rate);
 535                 spin_unlock_irqrestore(&clock_lock, flags);
 536
 537                 return rounded;
 538         }
 539
 540         return clk_get_rate(clk);
 541 }
 542 EXPORT_SYMBOL_GPL(clk_round_rate);
 543
 544 long clk_round_parent(struct clk *clk, unsigned long target,
 545                       unsigned long *best_freq, unsigned long *parent_freq,
 546                       unsigned int div_min, unsigned int div_max)
 547 {
 548         struct cpufreq_frequency_table *freq, *best = NULL;
 549         unsigned long error = ULONG_MAX, freq_high, freq_low, div;
 550         struct clk *parent = clk_get_parent(clk);
 551
 552         if (!parent) {
 553                 *parent_freq = 0;
 554                 *best_freq = clk_round_rate(clk, target);
 555                 return abs(target - *best_freq);
 556         }
 557
 558         for (freq = parent->freq_table; freq->frequency != CPUFREQ_TABLE_END;
 559              freq++) {
 560                 if (freq->frequency == CPUFREQ_ENTRY_INVALID)
 561                         continue;
 562
 563                 if (unlikely(freq->frequency / target <= div_min - 1)) {
 564                         unsigned long freq_max;
 565
 566                         freq_max = (freq->frequency + div_min / 2) / div_min;
 567                         if (error > target - freq_max) {
 568                                 error = target - freq_max;
 569                                 best = freq;
 570                                 if (best_freq)
 571                                         *best_freq = freq_max;
 572                         }
 573
 574                         pr_debug("too low freq %u, error %lu\n", freq->frequency,
 575                                  target - freq_max);
 576
 577                         if (!error)
 578                                 break;
 579
 580                         continue;
 581                 }
 582
 583                 if (unlikely(freq->frequency / target >= div_max)) {
 584                         unsigned long freq_min;
 585
 586                         freq_min = (freq->frequency + div_max / 2) / div_max;
 587                         if (error > freq_min - target) {
 588                                 error = freq_min - target;
 589                                 best = freq;
 590                                 if (best_freq)
 591                                         *best_freq = freq_min;
 592                         }
 593
 594                         pr_debug("too high freq %u, error %lu\n", freq->frequency,
 595                                  freq_min - target);
 596
 597                         if (!error)
 598                                 break;
 599
 600                         continue;
 601                 }
 602
 603                 div = freq->frequency / target;
 604                 freq_high = freq->frequency / div;
 605                 freq_low = freq->frequency / (div + 1);
 606
 607                 if (freq_high - target < error) {
 608                         error = freq_high - target;
 609                         best = freq;
 610                         if (best_freq)
 611                                 *best_freq = freq_high;
 612                 }
 613
 614                 if (target - freq_low < error) {
 615                         error = target - freq_low;
 616                         best = freq;
 617                         if (best_freq)
 618                                 *best_freq = freq_low;
 619                 }
 620
 621                 pr_debug("%u / %lu = %lu, / %lu = %lu, best %lu, parent %u\n",
 622                          freq->frequency, div, freq_high, div + 1, freq_low,
 623                          *best_freq, best->frequency);
 624
 625                 if (!error)
 626                         break;
 627         }
 628
 629         if (parent_freq)
 630                 *parent_freq = best->frequency;
 631
 632         return error;
 633 }
 634 EXPORT_SYMBOL_GPL(clk_round_parent);
 635
 636 #ifdef CONFIG_PM
 637 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 638 {
 639         static pm_message_t prev_state;
 640         struct clk *clkp;
 641
 642         switch (state.event) {
 643         case PM_EVENT_ON:
 644                 /* Resumeing from hibernation */
 645                 if (prev_state.event != PM_EVENT_FREEZE)
 646                         break;
 647
 648                 list_for_each_entry(clkp, &clock_list, node) {
 649                         if (likely(clkp->ops)) {
 650                                 unsigned long rate = clkp->rate;
 651
 652                                 if (likely(clkp->ops->set_parent))
 653                                         clkp->ops->set_parent(clkp,
 654                                                 clkp->parent);
 655                                 if (likely(clkp->ops->set_rate))
 656                                         clkp->ops->set_rate(clkp,
 657                                                 rate, NO_CHANGE);
 658                                 else if (likely(clkp->ops->recalc))
 659                                         clkp->rate = clkp->ops->recalc(clkp);
 660                         }
 661                 }
 662                 break;
 663         case PM_EVENT_FREEZE:
 664                 break;
 665         case PM_EVENT_SUSPEND:
 666                 break;
 667         }
 668
 669         prev_state = state;
 670         return 0;
 671 }
 672
 673 static int clks_sysdev_resume(struct sys_device *dev)
 674 {
 675         return clks_sysdev_suspend(dev, PMSG_ON);
 676 }
 677
 678 static struct sysdev_class clks_sysdev_class = {
 679         .name = "clks",
 680 };
 681
 682 static struct sysdev_driver clks_sysdev_driver = {
 683         .suspend = clks_sysdev_suspend,
 684         .resume = clks_sysdev_resume,
 685 };
 686
 687 static struct sys_device clks_sysdev_dev = {
 688         .cls = &clks_sysdev_class,
 689 };
 690
 691 static int __init clk_sysdev_init(void)
 692 {
 693         sysdev_class_register(&clks_sysdev_class);
 694         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 695         sysdev_register(&clks_sysdev_dev);
 696
 697         return 0;
 698 }
 699 subsys_initcall(clk_sysdev_init);
 700 #endif
 701
 702 /*
 703  *      debugfs support to trace clock tree hierarchy and attributes
 704  */
 705 static struct dentry *clk_debugfs_root;
 706
 707 static int clk_debugfs_register_one(struct clk *c)
 708 {
 709         int err;
 710         struct dentry *d, *child, *child_tmp;
 711         struct clk *pa = c->parent;
 712         char s[255];
 713         char *p = s;
 714
 715         p += sprintf(p, "%p", c);
 716         d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
 717         if (!d)
 718                 return -ENOMEM;
 719         c->dentry = d;
 720
 721         d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
 722         if (!d) {
 723                 err = -ENOMEM;
 724                 goto err_out;
 725         }
 726         d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
 727         if (!d) {
 728                 err = -ENOMEM;
 729                 goto err_out;
 730         }
 731         d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
 732         if (!d) {
 733                 err = -ENOMEM;
 734                 goto err_out;
 735         }
 736         return 0;
 737
 738 err_out:
 739         d = c->dentry;
 740         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 741                 debugfs_remove(child);
 742         debugfs_remove(c->dentry);
 743         return err;
 744 }
 745
 746 static int clk_debugfs_register(struct clk *c)
 747 {
 748         int err;
 749         struct clk *pa = c->parent;
 750
 751         if (pa && !pa->dentry) {
 752                 err = clk_debugfs_register(pa);
 753                 if (err)
 754                         return err;
 755         }
 756
 757         if (!c->dentry) {
 758                 err = clk_debugfs_register_one(c);
 759                 if (err)
 760                         return err;
 761         }
 762         return 0;
 763 }
 764
 765 static int __init clk_debugfs_init(void)
 766 {
 767         struct clk *c;
 768         struct dentry *d;
 769         int err;
 770
 771         d = debugfs_create_dir("clock", NULL);
 772         if (!d)
 773                 return -ENOMEM;
 774         clk_debugfs_root = d;
 775
 776         list_for_each_entry(c, &clock_list, node) {
 777                 err = clk_debugfs_register(c);
 778                 if (err)
 779                         goto err_out;
 780         }
 781         return 0;
 782 err_out:
 783         debugfs_remove_recursive(clk_debugfs_root);
 784         return err;
 785 }
 786 late_initcall(clk_debugfs_init);