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