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