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