drivers/sh/clk.c

   1 /*
   2  * drivers/sh/clk.c - 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 #include <linux/kernel.h>
  18 #include <linux/init.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/list.h>
  22 #include <linux/kobject.h>
  23 #include <linux/sysdev.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/err.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/debugfs.h>
  28 #include <linux/cpufreq.h>
  29 #include <linux/clk.h>
  30 #include <linux/sh_clk.h>
  31
  32 static LIST_HEAD(clock_list);
  33 static DEFINE_SPINLOCK(clock_lock);
  34 static DEFINE_MUTEX(clock_list_sem);
  35
  36 void clk_rate_table_build(struct clk *clk,
  37                           struct cpufreq_frequency_table *freq_table,
  38                           int nr_freqs,
  39                           struct clk_div_mult_table *src_table,
  40                           unsigned long *bitmap)
  41 {
  42         unsigned long mult, div;
  43         unsigned long freq;
  44         int i;
  45
  46         for (i = 0; i < nr_freqs; i++) {
  47                 div = 1;
  48                 mult = 1;
  49
  50                 if (src_table->divisors && i < src_table->nr_divisors)
  51                         div = src_table->divisors[i];
  52
  53                 if (src_table->multipliers && i < src_table->nr_multipliers)
  54                         mult = src_table->multipliers[i];
  55
  56                 if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
  57                         freq = CPUFREQ_ENTRY_INVALID;
  58                 else
  59                         freq = clk->parent->rate * mult / div;
  60
  61                 freq_table[i].index = i;
  62                 freq_table[i].frequency = freq;
  63         }
  64
  65         /* Termination entry */
  66         freq_table[i].index = i;
  67         freq_table[i].frequency = CPUFREQ_TABLE_END;
  68 }
  69
  70 long clk_rate_table_round(struct clk *clk,
  71                           struct cpufreq_frequency_table *freq_table,
  72                           unsigned long rate)
  73 {
  74         unsigned long rate_error, rate_error_prev = ~0UL;
  75         unsigned long rate_best_fit = rate;
  76         unsigned long highest, lowest;
  77         int i;
  78
  79         highest = 0;
  80         lowest = ~0UL;
  81
  82         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
  83                 unsigned long freq = freq_table[i].frequency;
  84
  85                 if (freq == CPUFREQ_ENTRY_INVALID)
  86                         continue;
  87
  88                 if (freq > highest)
  89                         highest = freq;
  90                 if (freq < lowest)
  91                         lowest = freq;
  92
  93                 rate_error = abs(freq - rate);
  94                 if (rate_error < rate_error_prev) {
  95                         rate_best_fit = freq;
  96                         rate_error_prev = rate_error;
  97                 }
  98
  99                 if (rate_error == 0)
 100                         break;
 101         }
 102
 103         if (rate >= highest)
 104                 rate_best_fit = highest;
 105         if (rate <= lowest)
 106                 rate_best_fit = lowest;
 107
 108         return rate_best_fit;
 109 }
 110
 111 int clk_rate_table_find(struct clk *clk,
 112                         struct cpufreq_frequency_table *freq_table,
 113                         unsigned long rate)
 114 {
 115         int i;
 116
 117         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 118                 unsigned long freq = freq_table[i].frequency;
 119
 120                 if (freq == CPUFREQ_ENTRY_INVALID)
 121                         continue;
 122
 123                 if (freq == rate)
 124                         return i;
 125         }
 126
 127         return -ENOENT;
 128 }
 129
 130 /* Used for clocks that always have same value as the parent clock */
 131 unsigned long followparent_recalc(struct clk *clk)
 132 {
 133         return clk->parent ? clk->parent->rate : 0;
 134 }
 135
 136 int clk_reparent(struct clk *child, struct clk *parent)
 137 {
 138         list_del_init(&child->sibling);
 139         if (parent)
 140                 list_add(&child->sibling, &parent->children);
 141         child->parent = parent;
 142
 143         /* now do the debugfs renaming to reattach the child
 144            to the proper parent */
 145
 146         return 0;
 147 }
 148
 149 /* Propagate rate to children */
 150 void propagate_rate(struct clk *tclk)
 151 {
 152         struct clk *clkp;
 153
 154         list_for_each_entry(clkp, &tclk->children, sibling) {
 155                 if (clkp->ops && clkp->ops->recalc)
 156                         clkp->rate = clkp->ops->recalc(clkp);
 157
 158                 propagate_rate(clkp);
 159         }
 160 }
 161
 162 static void __clk_disable(struct clk *clk)
 163 {
 164         if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
 165                  clk))
 166                 return;
 167
 168         if (!(--clk->usecount)) {
 169                 if (likely(clk->ops && clk->ops->disable))
 170                         clk->ops->disable(clk);
 171                 if (likely(clk->parent))
 172                         __clk_disable(clk->parent);
 173         }
 174 }
 175
 176 void clk_disable(struct clk *clk)
 177 {
 178         unsigned long flags;
 179
 180         if (!clk)
 181                 return;
 182
 183         spin_lock_irqsave(&clock_lock, flags);
 184         __clk_disable(clk);
 185         spin_unlock_irqrestore(&clock_lock, flags);
 186 }
 187 EXPORT_SYMBOL_GPL(clk_disable);
 188
 189 static int __clk_enable(struct clk *clk)
 190 {
 191         int ret = 0;
 192
 193         if (clk->usecount++ == 0) {
 194                 if (clk->parent) {
 195                         ret = __clk_enable(clk->parent);
 196                         if (unlikely(ret))
 197                                 goto err;
 198                 }
 199
 200                 if (clk->ops && clk->ops->enable) {
 201                         ret = clk->ops->enable(clk);
 202                         if (ret) {
 203                                 if (clk->parent)
 204                                         __clk_disable(clk->parent);
 205                                 goto err;
 206                         }
 207                 }
 208         }
 209
 210         return ret;
 211 err:
 212         clk->usecount--;
 213         return ret;
 214 }
 215
 216 int clk_enable(struct clk *clk)
 217 {
 218         unsigned long flags;
 219         int ret;
 220
 221         if (!clk)
 222                 return -EINVAL;
 223
 224         spin_lock_irqsave(&clock_lock, flags);
 225         ret = __clk_enable(clk);
 226         spin_unlock_irqrestore(&clock_lock, flags);
 227
 228         return ret;
 229 }
 230 EXPORT_SYMBOL_GPL(clk_enable);
 231
 232 static LIST_HEAD(root_clks);
 233
 234 /**
 235  * recalculate_root_clocks - recalculate and propagate all root clocks
 236  *
 237  * Recalculates all root clocks (clocks with no parent), which if the
 238  * clock's .recalc is set correctly, should also propagate their rates.
 239  * Called at init.
 240  */
 241 void recalculate_root_clocks(void)
 242 {
 243         struct clk *clkp;
 244
 245         list_for_each_entry(clkp, &root_clks, sibling) {
 246                 if (clkp->ops && clkp->ops->recalc)
 247                         clkp->rate = clkp->ops->recalc(clkp);
 248                 propagate_rate(clkp);
 249         }
 250 }
 251
 252 int clk_register(struct clk *clk)
 253 {
 254         if (clk == NULL || IS_ERR(clk))
 255                 return -EINVAL;
 256
 257         /*
 258          * trap out already registered clocks
 259          */
 260         if (clk->node.next || clk->node.prev)
 261                 return 0;
 262
 263         mutex_lock(&clock_list_sem);
 264
 265         INIT_LIST_HEAD(&clk->children);
 266         clk->usecount = 0;
 267
 268         if (clk->parent)
 269                 list_add(&clk->sibling, &clk->parent->children);
 270         else
 271                 list_add(&clk->sibling, &root_clks);
 272
 273         list_add(&clk->node, &clock_list);
 274         if (clk->ops && clk->ops->init)
 275                 clk->ops->init(clk);
 276         mutex_unlock(&clock_list_sem);
 277
 278         return 0;
 279 }
 280 EXPORT_SYMBOL_GPL(clk_register);
 281
 282 void clk_unregister(struct clk *clk)
 283 {
 284         mutex_lock(&clock_list_sem);
 285         list_del(&clk->sibling);
 286         list_del(&clk->node);
 287         mutex_unlock(&clock_list_sem);
 288 }
 289 EXPORT_SYMBOL_GPL(clk_unregister);
 290
 291 void clk_enable_init_clocks(void)
 292 {
 293         struct clk *clkp;
 294
 295         list_for_each_entry(clkp, &clock_list, node)
 296                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 297                         clk_enable(clkp);
 298 }
 299
 300 unsigned long clk_get_rate(struct clk *clk)
 301 {
 302         return clk->rate;
 303 }
 304 EXPORT_SYMBOL_GPL(clk_get_rate);
 305
 306 int clk_set_rate(struct clk *clk, unsigned long rate)
 307 {
 308         return clk_set_rate_ex(clk, rate, 0);
 309 }
 310 EXPORT_SYMBOL_GPL(clk_set_rate);
 311
 312 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 313 {
 314         int ret = -EOPNOTSUPP;
 315         unsigned long flags;
 316
 317         spin_lock_irqsave(&clock_lock, flags);
 318
 319         if (likely(clk->ops && clk->ops->set_rate)) {
 320                 ret = clk->ops->set_rate(clk, rate, algo_id);
 321                 if (ret != 0)
 322                         goto out_unlock;
 323         } else {
 324                 clk->rate = rate;
 325                 ret = 0;
 326         }
 327
 328         if (clk->ops && clk->ops->recalc)
 329                 clk->rate = clk->ops->recalc(clk);
 330
 331         propagate_rate(clk);
 332
 333 out_unlock:
 334         spin_unlock_irqrestore(&clock_lock, flags);
 335
 336         return ret;
 337 }
 338 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 339
 340 int clk_set_parent(struct clk *clk, struct clk *parent)
 341 {
 342         unsigned long flags;
 343         int ret = -EINVAL;
 344
 345         if (!parent || !clk)
 346                 return ret;
 347         if (clk->parent == parent)
 348                 return 0;
 349
 350         spin_lock_irqsave(&clock_lock, flags);
 351         if (clk->usecount == 0) {
 352                 if (clk->ops->set_parent)
 353                         ret = clk->ops->set_parent(clk, parent);
 354                 else
 355                         ret = clk_reparent(clk, parent);
 356
 357                 if (ret == 0) {
 358                         if (clk->ops->recalc)
 359                                 clk->rate = clk->ops->recalc(clk);
 360                         pr_debug("clock: set parent of %p to %p (new rate %ld)\n",
 361                                  clk, clk->parent, clk->rate);
 362                         propagate_rate(clk);
 363                 }
 364         } else
 365                 ret = -EBUSY;
 366         spin_unlock_irqrestore(&clock_lock, flags);
 367
 368         return ret;
 369 }
 370 EXPORT_SYMBOL_GPL(clk_set_parent);
 371
 372 struct clk *clk_get_parent(struct clk *clk)
 373 {
 374         return clk->parent;
 375 }
 376 EXPORT_SYMBOL_GPL(clk_get_parent);
 377
 378 long clk_round_rate(struct clk *clk, unsigned long rate)
 379 {
 380         if (likely(clk->ops && clk->ops->round_rate)) {
 381                 unsigned long flags, rounded;
 382
 383                 spin_lock_irqsave(&clock_lock, flags);
 384                 rounded = clk->ops->round_rate(clk, rate);
 385                 spin_unlock_irqrestore(&clock_lock, flags);
 386
 387                 return rounded;
 388         }
 389
 390         return clk_get_rate(clk);
 391 }
 392 EXPORT_SYMBOL_GPL(clk_round_rate);
 393
 394 #ifdef CONFIG_PM
 395 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 396 {
 397         static pm_message_t prev_state;
 398         struct clk *clkp;
 399
 400         switch (state.event) {
 401         case PM_EVENT_ON:
 402                 /* Resumeing from hibernation */
 403                 if (prev_state.event != PM_EVENT_FREEZE)
 404                         break;
 405
 406                 list_for_each_entry(clkp, &clock_list, node) {
 407                         if (likely(clkp->ops)) {
 408                                 unsigned long rate = clkp->rate;
 409
 410                                 if (likely(clkp->ops->set_parent))
 411                                         clkp->ops->set_parent(clkp,
 412                                                 clkp->parent);
 413                                 if (likely(clkp->ops->set_rate))
 414                                         clkp->ops->set_rate(clkp,
 415                                                 rate, NO_CHANGE);
 416                                 else if (likely(clkp->ops->recalc))
 417                                         clkp->rate = clkp->ops->recalc(clkp);
 418                         }
 419                 }
 420                 break;
 421         case PM_EVENT_FREEZE:
 422                 break;
 423         case PM_EVENT_SUSPEND:
 424                 break;
 425         }
 426
 427         prev_state = state;
 428         return 0;
 429 }
 430
 431 static int clks_sysdev_resume(struct sys_device *dev)
 432 {
 433         return clks_sysdev_suspend(dev, PMSG_ON);
 434 }
 435
 436 static struct sysdev_class clks_sysdev_class = {
 437         .name = "clks",
 438 };
 439
 440 static struct sysdev_driver clks_sysdev_driver = {
 441         .suspend = clks_sysdev_suspend,
 442         .resume = clks_sysdev_resume,
 443 };
 444
 445 static struct sys_device clks_sysdev_dev = {
 446         .cls = &clks_sysdev_class,
 447 };
 448
 449 static int __init clk_sysdev_init(void)
 450 {
 451         sysdev_class_register(&clks_sysdev_class);
 452         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 453         sysdev_register(&clks_sysdev_dev);
 454
 455         return 0;
 456 }
 457 subsys_initcall(clk_sysdev_init);
 458 #endif
 459
 460 /*
 461  *      debugfs support to trace clock tree hierarchy and attributes
 462  */
 463 static struct dentry *clk_debugfs_root;
 464
 465 static int clk_debugfs_register_one(struct clk *c)
 466 {
 467         int err;
 468         struct dentry *d, *child, *child_tmp;
 469         struct clk *pa = c->parent;
 470         char s[255];
 471         char *p = s;
 472
 473         p += sprintf(p, "%p", c);
 474         d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
 475         if (!d)
 476                 return -ENOMEM;
 477         c->dentry = d;
 478
 479         d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
 480         if (!d) {
 481                 err = -ENOMEM;
 482                 goto err_out;
 483         }
 484         d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
 485         if (!d) {
 486                 err = -ENOMEM;
 487                 goto err_out;
 488         }
 489         d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
 490         if (!d) {
 491                 err = -ENOMEM;
 492                 goto err_out;
 493         }
 494         return 0;
 495
 496 err_out:
 497         d = c->dentry;
 498         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 499                 debugfs_remove(child);
 500         debugfs_remove(c->dentry);
 501         return err;
 502 }
 503
 504 static int clk_debugfs_register(struct clk *c)
 505 {
 506         int err;
 507         struct clk *pa = c->parent;
 508
 509         if (pa && !pa->dentry) {
 510                 err = clk_debugfs_register(pa);
 511                 if (err)
 512                         return err;
 513         }
 514
 515         if (!c->dentry) {
 516                 err = clk_debugfs_register_one(c);
 517                 if (err)
 518                         return err;
 519         }
 520         return 0;
 521 }
 522
 523 static int __init clk_debugfs_init(void)
 524 {
 525         struct clk *c;
 526         struct dentry *d;
 527         int err;
 528
 529         d = debugfs_create_dir("clock", NULL);
 530         if (!d)
 531                 return -ENOMEM;
 532         clk_debugfs_root = d;
 533
 534         list_for_each_entry(c, &clock_list, node) {
 535                 err = clk_debugfs_register(c);
 536                 if (err)
 537                         goto err_out;
 538         }
 539         return 0;
 540 err_out:
 541         debugfs_remove_recursive(clk_debugfs_root);
 542         return err;
 543 }
 544 late_initcall(clk_debugfs_init);