arch/arm/plat-omap/clock.c

   1 /*
   2  *  linux/arch/arm/plat-omap/clock.c
   3  *
   4  *  Copyright (C) 2004 - 2008 Nokia corporation
   5  *  Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
   6  *
   7  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/list.h>
  17 #include <linux/errno.h>
  18 #include <linux/err.h>
  19 #include <linux/string.h>
  20 #include <linux/clk.h>
  21 #include <linux/mutex.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/cpufreq.h>
  24 #include <linux/debugfs.h>
  25 #include <linux/io.h>
  26
  27 #include <mach/clock.h>
  28
  29 static LIST_HEAD(clocks);
  30 static DEFINE_MUTEX(clocks_mutex);
  31 static DEFINE_SPINLOCK(clockfw_lock);
  32
  33 static struct clk_functions *arch_clock;
  34
  35 /*-------------------------------------------------------------------------
  36  * Standard clock functions defined in include/linux/clk.h
  37  *-------------------------------------------------------------------------*/
  38
  39 /*
  40  * Returns a clock. Note that we first try to use device id on the bus
  41  * and clock name. If this fails, we try to use clock name only.
  42  */
  43 struct clk * clk_get(struct device *dev, const char *id)
  44 {
  45         struct clk *p, *clk = ERR_PTR(-ENOENT);
  46         int idno;
  47
  48         if (dev == NULL || dev->bus != &platform_bus_type)
  49                 idno = -1;
  50         else
  51                 idno = to_platform_device(dev)->id;
  52
  53         mutex_lock(&clocks_mutex);
  54
  55         list_for_each_entry(p, &clocks, node) {
  56                 if (p->id == idno && strcmp(id, p->name) == 0) {
  57                         clk = p;
  58                         goto found;
  59                 }
  60         }
  61
  62         list_for_each_entry(p, &clocks, node) {
  63                 if (strcmp(id, p->name) == 0) {
  64                         clk = p;
  65                         break;
  66                 }
  67         }
  68
  69 found:
  70         mutex_unlock(&clocks_mutex);
  71
  72         return clk;
  73 }
  74 EXPORT_SYMBOL(clk_get);
  75
  76 int clk_enable(struct clk *clk)
  77 {
  78         unsigned long flags;
  79         int ret = 0;
  80
  81         if (clk == NULL || IS_ERR(clk))
  82                 return -EINVAL;
  83
  84         spin_lock_irqsave(&clockfw_lock, flags);
  85         if (arch_clock->clk_enable)
  86                 ret = arch_clock->clk_enable(clk);
  87         spin_unlock_irqrestore(&clockfw_lock, flags);
  88
  89         return ret;
  90 }
  91 EXPORT_SYMBOL(clk_enable);
  92
  93 void clk_disable(struct clk *clk)
  94 {
  95         unsigned long flags;
  96
  97         if (clk == NULL || IS_ERR(clk))
  98                 return;
  99
 100         spin_lock_irqsave(&clockfw_lock, flags);
 101         if (clk->usecount == 0) {
 102                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
 103                        clk->name);
 104                 WARN_ON(1);
 105                 goto out;
 106         }
 107
 108         if (arch_clock->clk_disable)
 109                 arch_clock->clk_disable(clk);
 110
 111 out:
 112         spin_unlock_irqrestore(&clockfw_lock, flags);
 113 }
 114 EXPORT_SYMBOL(clk_disable);
 115
 116 int clk_get_usecount(struct clk *clk)
 117 {
 118         unsigned long flags;
 119         int ret = 0;
 120
 121         if (clk == NULL || IS_ERR(clk))
 122                 return 0;
 123
 124         spin_lock_irqsave(&clockfw_lock, flags);
 125         ret = clk->usecount;
 126         spin_unlock_irqrestore(&clockfw_lock, flags);
 127
 128         return ret;
 129 }
 130 EXPORT_SYMBOL(clk_get_usecount);
 131
 132 unsigned long clk_get_rate(struct clk *clk)
 133 {
 134         unsigned long flags;
 135         unsigned long ret = 0;
 136
 137         if (clk == NULL || IS_ERR(clk))
 138                 return 0;
 139
 140         spin_lock_irqsave(&clockfw_lock, flags);
 141         ret = clk->rate;
 142         spin_unlock_irqrestore(&clockfw_lock, flags);
 143
 144         return ret;
 145 }
 146 EXPORT_SYMBOL(clk_get_rate);
 147
 148 void clk_put(struct clk *clk)
 149 {
 150 }
 151 EXPORT_SYMBOL(clk_put);
 152
 153 /*-------------------------------------------------------------------------
 154  * Optional clock functions defined in include/linux/clk.h
 155  *-------------------------------------------------------------------------*/
 156
 157 long clk_round_rate(struct clk *clk, unsigned long rate)
 158 {
 159         unsigned long flags;
 160         long ret = 0;
 161
 162         if (clk == NULL || IS_ERR(clk))
 163                 return ret;
 164
 165         spin_lock_irqsave(&clockfw_lock, flags);
 166         if (arch_clock->clk_round_rate)
 167                 ret = arch_clock->clk_round_rate(clk, rate);
 168         spin_unlock_irqrestore(&clockfw_lock, flags);
 169
 170         return ret;
 171 }
 172 EXPORT_SYMBOL(clk_round_rate);
 173
 174 int clk_set_rate(struct clk *clk, unsigned long rate)
 175 {
 176         unsigned long flags;
 177         int ret = -EINVAL;
 178
 179         if (clk == NULL || IS_ERR(clk))
 180                 return ret;
 181
 182         spin_lock_irqsave(&clockfw_lock, flags);
 183         if (arch_clock->clk_set_rate)
 184                 ret = arch_clock->clk_set_rate(clk, rate);
 185         spin_unlock_irqrestore(&clockfw_lock, flags);
 186
 187         return ret;
 188 }
 189 EXPORT_SYMBOL(clk_set_rate);
 190
 191 int clk_set_parent(struct clk *clk, struct clk *parent)
 192 {
 193         unsigned long flags;
 194         int ret = -EINVAL;
 195
 196         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 197                 return ret;
 198
 199         spin_lock_irqsave(&clockfw_lock, flags);
 200         if (arch_clock->clk_set_parent)
 201                 ret =  arch_clock->clk_set_parent(clk, parent);
 202         spin_unlock_irqrestore(&clockfw_lock, flags);
 203
 204         return ret;
 205 }
 206 EXPORT_SYMBOL(clk_set_parent);
 207
 208 struct clk *clk_get_parent(struct clk *clk)
 209 {
 210         return clk->parent;
 211 }
 212 EXPORT_SYMBOL(clk_get_parent);
 213
 214 /*-------------------------------------------------------------------------
 215  * OMAP specific clock functions shared between omap1 and omap2
 216  *-------------------------------------------------------------------------*/
 217
 218 unsigned int __initdata mpurate;
 219
 220 /*
 221  * By default we use the rate set by the bootloader.
 222  * You can override this with mpurate= cmdline option.
 223  */
 224 static int __init omap_clk_setup(char *str)
 225 {
 226         get_option(&str, &mpurate);
 227
 228         if (!mpurate)
 229                 return 1;
 230
 231         if (mpurate < 1000)
 232                 mpurate *= 1000000;
 233
 234         return 1;
 235 }
 236 __setup("mpurate=", omap_clk_setup);
 237
 238 /* Used for clocks that always have same value as the parent clock */
 239 void followparent_recalc(struct clk *clk)
 240 {
 241         if (clk == NULL || IS_ERR(clk))
 242                 return;
 243
 244         clk->rate = clk->parent->rate;
 245         if (unlikely(clk->flags & RATE_PROPAGATES))
 246                 propagate_rate(clk);
 247 }
 248
 249 /* Propagate rate to children */
 250 void propagate_rate(struct clk * tclk)
 251 {
 252         struct clk *clkp;
 253
 254         if (tclk == NULL || IS_ERR(tclk))
 255                 return;
 256
 257         list_for_each_entry(clkp, &clocks, node) {
 258                 if (likely(clkp->parent != tclk))
 259                         continue;
 260                 if (likely((u32)clkp->recalc))
 261                         clkp->recalc(clkp);
 262         }
 263 }
 264
 265 /**
 266  * recalculate_root_clocks - recalculate and propagate all root clocks
 267  *
 268  * Recalculates all root clocks (clocks with no parent), which if the
 269  * clock's .recalc is set correctly, should also propagate their rates.
 270  * Called at init.
 271  */
 272 void recalculate_root_clocks(void)
 273 {
 274         struct clk *clkp;
 275
 276         list_for_each_entry(clkp, &clocks, node) {
 277                 if (unlikely(!clkp->parent) && likely((u32)clkp->recalc))
 278                         clkp->recalc(clkp);
 279         }
 280 }
 281
 282 int clk_register(struct clk *clk)
 283 {
 284         if (clk == NULL || IS_ERR(clk))
 285                 return -EINVAL;
 286
 287         mutex_lock(&clocks_mutex);
 288         list_add(&clk->node, &clocks);
 289         if (clk->init)
 290                 clk->init(clk);
 291         mutex_unlock(&clocks_mutex);
 292
 293         return 0;
 294 }
 295 EXPORT_SYMBOL(clk_register);
 296
 297 void clk_unregister(struct clk *clk)
 298 {
 299         if (clk == NULL || IS_ERR(clk))
 300                 return;
 301
 302         mutex_lock(&clocks_mutex);
 303         list_del(&clk->node);
 304         mutex_unlock(&clocks_mutex);
 305 }
 306 EXPORT_SYMBOL(clk_unregister);
 307
 308 void clk_enable_init_clocks(void)
 309 {
 310         struct clk *clkp;
 311
 312         list_for_each_entry(clkp, &clocks, node) {
 313                 if (clkp->flags & ENABLE_ON_INIT)
 314                         clk_enable(clkp);
 315         }
 316 }
 317 EXPORT_SYMBOL(clk_enable_init_clocks);
 318
 319 /*
 320  * Low level helpers
 321  */
 322 static int clkll_enable_null(struct clk *clk)
 323 {
 324         return 0;
 325 }
 326
 327 static void clkll_disable_null(struct clk *clk)
 328 {
 329 }
 330
 331 const struct clkops clkops_null = {
 332         .enable         = clkll_enable_null,
 333         .disable        = clkll_disable_null,
 334 };
 335
 336 #ifdef CONFIG_CPU_FREQ
 337 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 338 {
 339         unsigned long flags;
 340
 341         spin_lock_irqsave(&clockfw_lock, flags);
 342         if (arch_clock->clk_init_cpufreq_table)
 343                 arch_clock->clk_init_cpufreq_table(table);
 344         spin_unlock_irqrestore(&clockfw_lock, flags);
 345 }
 346 EXPORT_SYMBOL(clk_init_cpufreq_table);
 347 #endif
 348
 349 /*-------------------------------------------------------------------------*/
 350
 351 #ifdef CONFIG_OMAP_RESET_CLOCKS
 352 /*
 353  * Disable any unused clocks left on by the bootloader
 354  */
 355 static int __init clk_disable_unused(void)
 356 {
 357         struct clk *ck;
 358         unsigned long flags;
 359
 360         list_for_each_entry(ck, &clocks, node) {
 361                 if (ck->ops == &clkops_null)
 362                         continue;
 363
 364                 if (ck->usecount > 0 || ck->enable_reg == 0)
 365                         continue;
 366
 367                 spin_lock_irqsave(&clockfw_lock, flags);
 368                 if (arch_clock->clk_disable_unused)
 369                         arch_clock->clk_disable_unused(ck);
 370                 spin_unlock_irqrestore(&clockfw_lock, flags);
 371         }
 372
 373         return 0;
 374 }
 375 late_initcall(clk_disable_unused);
 376 #endif
 377
 378 int __init clk_init(struct clk_functions * custom_clocks)
 379 {
 380         if (!custom_clocks) {
 381                 printk(KERN_ERR "No custom clock functions registered\n");
 382                 BUG();
 383         }
 384
 385         arch_clock = custom_clocks;
 386
 387         return 0;
 388 }
 389
 390 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 391 /*
 392  *      debugfs support to trace clock tree hierarchy and attributes
 393  */
 394 static struct dentry *clk_debugfs_root;
 395
 396 static int clk_debugfs_register_one(struct clk *c)
 397 {
 398         int err;
 399         struct dentry *d, *child;
 400         struct clk *pa = c->parent;
 401         char s[255];
 402         char *p = s;
 403
 404         p += sprintf(p, "%s", c->name);
 405         if (c->id != 0)
 406                 sprintf(p, ":%d", c->id);
 407         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 408         if (!d)
 409                 return -ENOMEM;
 410         c->dent = d;
 411
 412         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 413         if (!d) {
 414                 err = -ENOMEM;
 415                 goto err_out;
 416         }
 417         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 418         if (!d) {
 419                 err = -ENOMEM;
 420                 goto err_out;
 421         }
 422         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 423         if (!d) {
 424                 err = -ENOMEM;
 425                 goto err_out;
 426         }
 427         return 0;
 428
 429 err_out:
 430         d = c->dent;
 431         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 432                 debugfs_remove(child);
 433         debugfs_remove(c->dent);
 434         return err;
 435 }
 436
 437 static int clk_debugfs_register(struct clk *c)
 438 {
 439         int err;
 440         struct clk *pa = c->parent;
 441
 442         if (pa && !pa->dent) {
 443                 err = clk_debugfs_register(pa);
 444                 if (err)
 445                         return err;
 446         }
 447
 448         if (!c->dent) {
 449                 err = clk_debugfs_register_one(c);
 450                 if (err)
 451                         return err;
 452         }
 453         return 0;
 454 }
 455
 456 static int __init clk_debugfs_init(void)
 457 {
 458         struct clk *c;
 459         struct dentry *d;
 460         int err;
 461
 462         d = debugfs_create_dir("clock", NULL);
 463         if (!d)
 464                 return -ENOMEM;
 465         clk_debugfs_root = d;
 466
 467         list_for_each_entry(c, &clocks, node) {
 468                 err = clk_debugfs_register(c);
 469                 if (err)
 470                         goto err_out;
 471         }
 472         return 0;
 473 err_out:
 474         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 475         return err;
 476 }
 477 late_initcall(clk_debugfs_init);
 478
 479 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */