drivers/sh/clk.c

   1 /*
   2  * drivers/sh/clk.c - SuperH clock framework
   3  *
   4  *  Copyright (C) 2005 - 2009  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 = lowest = 0;
  80
  81         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
  82                 unsigned long freq = freq_table[i].frequency;
  83
  84                 if (freq == CPUFREQ_ENTRY_INVALID)
  85                         continue;
  86
  87                 if (freq > highest)
  88                         highest = freq;
  89                 if (freq < lowest)
  90                         lowest = freq;
  91
  92                 rate_error = abs(freq - rate);
  93                 if (rate_error < rate_error_prev) {
  94                         rate_best_fit = freq;
  95                         rate_error_prev = rate_error;
  96                 }
  97
  98                 if (rate_error == 0)
  99                         break;
 100         }
 101
 102         if (rate >= highest)
 103                 rate_best_fit = highest;
 104         if (rate <= lowest)
 105                 rate_best_fit = lowest;
 106
 107         return rate_best_fit;
 108 }
 109
 110 int clk_rate_table_find(struct clk *clk,
 111                         struct cpufreq_frequency_table *freq_table,
 112                         unsigned long rate)
 113 {
 114         int i;
 115
 116         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 117                 unsigned long freq = freq_table[i].frequency;
 118
 119                 if (freq == CPUFREQ_ENTRY_INVALID)
 120                         continue;
 121
 122                 if (freq == rate)
 123                         return i;
 124         }
 125
 126         return -ENOENT;
 127 }
 128
 129 /* Used for clocks that always have same value as the parent clock */
 130 unsigned long followparent_recalc(struct clk *clk)
 131 {
 132         return clk->parent ? clk->parent->rate : 0;
 133 }
 134
 135 int clk_reparent(struct clk *child, struct clk *parent)
 136 {
 137         list_del_init(&child->sibling);
 138         if (parent)
 139                 list_add(&child->sibling, &parent->children);
 140         child->parent = parent;
 141
 142         /* now do the debugfs renaming to reattach the child
 143            to the proper parent */
 144
 145         return 0;
 146 }
 147
 148 /* Propagate rate to children */
 149 void propagate_rate(struct clk *tclk)
 150 {
 151         struct clk *clkp;
 152
 153         list_for_each_entry(clkp, &tclk->children, sibling) {
 154                 if (clkp->ops && clkp->ops->recalc)
 155                         clkp->rate = clkp->ops->recalc(clkp);
 156
 157                 propagate_rate(clkp);
 158         }
 159 }
 160
 161 static void __clk_disable(struct clk *clk)
 162 {
 163         if (clk->usecount == 0) {
 164                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
 165                        clk->name);
 166                 WARN_ON(1);
 167                 return;
 168         }
 169
 170         if (!(--clk->usecount)) {
 171                 if (likely(clk->ops && clk->ops->disable))
 172                         clk->ops->disable(clk);
 173                 if (likely(clk->parent))
 174                         __clk_disable(clk->parent);
 175         }
 176 }
 177
 178 void clk_disable(struct clk *clk)
 179 {
 180         unsigned long flags;
 181
 182         if (!clk)
 183                 return;
 184
 185         spin_lock_irqsave(&clock_lock, flags);
 186         __clk_disable(clk);
 187         spin_unlock_irqrestore(&clock_lock, flags);
 188 }
 189 EXPORT_SYMBOL_GPL(clk_disable);
 190
 191 static int __clk_enable(struct clk *clk)
 192 {
 193         int ret = 0;
 194
 195         if (clk->usecount++ == 0) {
 196                 if (clk->parent) {
 197                         ret = __clk_enable(clk->parent);
 198                         if (unlikely(ret))
 199                                 goto err;
 200                 }
 201
 202                 if (clk->ops && clk->ops->enable) {
 203                         ret = clk->ops->enable(clk);
 204                         if (ret) {
 205                                 if (clk->parent)
 206                                         __clk_disable(clk->parent);
 207                                 goto err;
 208                         }
 209                 }
 210         }
 211
 212         return ret;
 213 err:
 214         clk->usecount--;
 215         return ret;
 216 }
 217
 218 int clk_enable(struct clk *clk)
 219 {
 220         unsigned long flags;
 221         int ret;
 222
 223         if (!clk)
 224                 return -EINVAL;
 225
 226         spin_lock_irqsave(&clock_lock, flags);
 227         ret = __clk_enable(clk);
 228         spin_unlock_irqrestore(&clock_lock, flags);
 229
 230         return ret;
 231 }
 232 EXPORT_SYMBOL_GPL(clk_enable);
 233
 234 static LIST_HEAD(root_clks);
 235
 236 /**
 237  * recalculate_root_clocks - recalculate and propagate all root clocks
 238  *
 239  * Recalculates all root clocks (clocks with no parent), which if the
 240  * clock's .recalc is set correctly, should also propagate their rates.
 241  * Called at init.
 242  */
 243 void recalculate_root_clocks(void)
 244 {
 245         struct clk *clkp;
 246
 247         list_for_each_entry(clkp, &root_clks, sibling) {
 248                 if (clkp->ops && clkp->ops->recalc)
 249                         clkp->rate = clkp->ops->recalc(clkp);
 250                 propagate_rate(clkp);
 251         }
 252 }
 253
 254 int clk_register(struct clk *clk)
 255 {
 256         if (clk == NULL || IS_ERR(clk))
 257                 return -EINVAL;
 258
 259         /*
 260          * trap out already registered clocks
 261          */
 262         if (clk->node.next || clk->node.prev)
 263                 return 0;
 264
 265         mutex_lock(&clock_list_sem);
 266
 267         INIT_LIST_HEAD(&clk->children);
 268         clk->usecount = 0;
 269
 270         if (clk->parent)
 271                 list_add(&clk->sibling, &clk->parent->children);
 272         else
 273                 list_add(&clk->sibling, &root_clks);
 274
 275         list_add(&clk->node, &clock_list);
 276         if (clk->ops && clk->ops->init)
 277                 clk->ops->init(clk);
 278         mutex_unlock(&clock_list_sem);
 279
 280         return 0;
 281 }
 282 EXPORT_SYMBOL_GPL(clk_register);
 283
 284 void clk_unregister(struct clk *clk)
 285 {
 286         mutex_lock(&clock_list_sem);
 287         list_del(&clk->sibling);
 288         list_del(&clk->node);
 289         mutex_unlock(&clock_list_sem);
 290 }
 291 EXPORT_SYMBOL_GPL(clk_unregister);
 292
 293 void clk_enable_init_clocks(void)
 294 {
 295         struct clk *clkp;
 296
 297         list_for_each_entry(clkp, &clock_list, node)
 298                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 299                         clk_enable(clkp);
 300 }
 301
 302 unsigned long clk_get_rate(struct clk *clk)
 303 {
 304         return clk->rate;
 305 }
 306 EXPORT_SYMBOL_GPL(clk_get_rate);
 307
 308 int clk_set_rate(struct clk *clk, unsigned long rate)
 309 {
 310         return clk_set_rate_ex(clk, rate, 0);
 311 }
 312 EXPORT_SYMBOL_GPL(clk_set_rate);
 313
 314 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 315 {
 316         int ret = -EOPNOTSUPP;
 317         unsigned long flags;
 318
 319         spin_lock_irqsave(&clock_lock, flags);
 320
 321         if (likely(clk->ops && clk->ops->set_rate)) {
 322                 ret = clk->ops->set_rate(clk, rate, algo_id);
 323                 if (ret != 0)
 324                         goto out_unlock;
 325         } else {
 326                 clk->rate = rate;
 327                 ret = 0;
 328         }
 329
 330         if (clk->ops && clk->ops->recalc)
 331                 clk->rate = clk->ops->recalc(clk);
 332
 333         propagate_rate(clk);
 334
 335 out_unlock:
 336         spin_unlock_irqrestore(&clock_lock, flags);
 337
 338         return ret;
 339 }
 340 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 341
 342 int clk_set_parent(struct clk *clk, struct clk *parent)
 343 {
 344         unsigned long flags;
 345         int ret = -EINVAL;
 346
 347         if (!parent || !clk)
 348                 return ret;
 349         if (clk->parent == parent)
 350                 return 0;
 351
 352         spin_lock_irqsave(&clock_lock, flags);
 353         if (clk->usecount == 0) {
 354                 if (clk->ops->set_parent)
 355                         ret = clk->ops->set_parent(clk, parent);
 356                 else
 357                         ret = clk_reparent(clk, parent);
 358
 359                 if (ret == 0) {
 360                         pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
 361                                  clk->name, clk->parent->name, clk->rate);
 362                         if (clk->ops->recalc)
 363                                 clk->rate = clk->ops->recalc(clk);
 364                         propagate_rate(clk);
 365                 }
 366         } else
 367                 ret = -EBUSY;
 368         spin_unlock_irqrestore(&clock_lock, flags);
 369
 370         return ret;
 371 }
 372 EXPORT_SYMBOL_GPL(clk_set_parent);
 373
 374 struct clk *clk_get_parent(struct clk *clk)
 375 {
 376         return clk->parent;
 377 }
 378 EXPORT_SYMBOL_GPL(clk_get_parent);
 379
 380 long clk_round_rate(struct clk *clk, unsigned long rate)
 381 {
 382         if (likely(clk->ops && clk->ops->round_rate)) {
 383                 unsigned long flags, rounded;
 384
 385                 spin_lock_irqsave(&clock_lock, flags);
 386                 rounded = clk->ops->round_rate(clk, rate);
 387                 spin_unlock_irqrestore(&clock_lock, flags);
 388
 389                 return rounded;
 390         }
 391
 392         return clk_get_rate(clk);
 393 }
 394 EXPORT_SYMBOL_GPL(clk_round_rate);
 395
 396 #ifdef CONFIG_PM
 397 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 398 {
 399         static pm_message_t prev_state;
 400         struct clk *clkp;
 401
 402         switch (state.event) {
 403         case PM_EVENT_ON:
 404                 /* Resumeing from hibernation */
 405                 if (prev_state.event != PM_EVENT_FREEZE)
 406                         break;
 407
 408                 list_for_each_entry(clkp, &clock_list, node) {
 409                         if (likely(clkp->ops)) {
 410                                 unsigned long rate = clkp->rate;
 411
 412                                 if (likely(clkp->ops->set_parent))
 413                                         clkp->ops->set_parent(clkp,
 414                                                 clkp->parent);
 415                                 if (likely(clkp->ops->set_rate))
 416                                         clkp->ops->set_rate(clkp,
 417                                                 rate, NO_CHANGE);
 418                                 else if (likely(clkp->ops->recalc))
 419                                         clkp->rate = clkp->ops->recalc(clkp);
 420                         }
 421                 }
 422                 break;
 423         case PM_EVENT_FREEZE:
 424                 break;
 425         case PM_EVENT_SUSPEND:
 426                 break;
 427         }
 428
 429         prev_state = state;
 430         return 0;
 431 }
 432
 433 static int clks_sysdev_resume(struct sys_device *dev)
 434 {
 435         return clks_sysdev_suspend(dev, PMSG_ON);
 436 }
 437
 438 static struct sysdev_class clks_sysdev_class = {
 439         .name = "clks",
 440 };
 441
 442 static struct sysdev_driver clks_sysdev_driver = {
 443         .suspend = clks_sysdev_suspend,
 444         .resume = clks_sysdev_resume,
 445 };
 446
 447 static struct sys_device clks_sysdev_dev = {
 448         .cls = &clks_sysdev_class,
 449 };
 450
 451 static int __init clk_sysdev_init(void)
 452 {
 453         sysdev_class_register(&clks_sysdev_class);
 454         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 455         sysdev_register(&clks_sysdev_dev);
 456
 457         return 0;
 458 }
 459 subsys_initcall(clk_sysdev_init);
 460 #endif
 461
 462 /*
 463  *      debugfs support to trace clock tree hierarchy and attributes
 464  */
 465 static struct dentry *clk_debugfs_root;
 466
 467 static int clk_debugfs_register_one(struct clk *c)
 468 {
 469         int err;
 470         struct dentry *d, *child, *child_tmp;
 471         struct clk *pa = c->parent;
 472         char s[255];
 473         char *p = s;
 474
 475         p += sprintf(p, "%s", c->name);
 476         if (c->id >= 0)
 477                 sprintf(p, ":%d", c->id);
 478         d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
 479         if (!d)
 480                 return -ENOMEM;
 481         c->dentry = d;
 482
 483         d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
 484         if (!d) {
 485                 err = -ENOMEM;
 486                 goto err_out;
 487         }
 488         d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
 489         if (!d) {
 490                 err = -ENOMEM;
 491                 goto err_out;
 492         }
 493         d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
 494         if (!d) {
 495                 err = -ENOMEM;
 496                 goto err_out;
 497         }
 498         return 0;
 499
 500 err_out:
 501         d = c->dentry;
 502         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 503                 debugfs_remove(child);
 504         debugfs_remove(c->dentry);
 505         return err;
 506 }
 507
 508 static int clk_debugfs_register(struct clk *c)
 509 {
 510         int err;
 511         struct clk *pa = c->parent;
 512
 513         if (pa && !pa->dentry) {
 514                 err = clk_debugfs_register(pa);
 515                 if (err)
 516                         return err;
 517         }
 518
 519         if (!c->dentry && c->name) {
 520                 err = clk_debugfs_register_one(c);
 521                 if (err)
 522                         return err;
 523         }
 524         return 0;
 525 }
 526
 527 static int __init clk_debugfs_init(void)
 528 {
 529         struct clk *c;
 530         struct dentry *d;
 531         int err;
 532
 533         d = debugfs_create_dir("clock", NULL);
 534         if (!d)
 535                 return -ENOMEM;
 536         clk_debugfs_root = d;
 537
 538         list_for_each_entry(c, &clock_list, node) {
 539                 err = clk_debugfs_register(c);
 540                 if (err)
 541                         goto err_out;
 542         }
 543         return 0;
 544 err_out:
 545         debugfs_remove_recursive(clk_debugfs_root);
 546         return err;
 547 }
 548 late_initcall(clk_debugfs_init);