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         if (ret == 0 && (clk->flags & RATE_PROPAGATES))
 186                 propagate_rate(clk);
 187         spin_unlock_irqrestore(&clockfw_lock, flags);
 188
 189         return ret;
 190 }
 191 EXPORT_SYMBOL(clk_set_rate);
 192
 193 int clk_set_parent(struct clk *clk, struct clk *parent)
 194 {
 195         unsigned long flags;
 196         int ret = -EINVAL;
 197
 198         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 199                 return ret;
 200
 201         spin_lock_irqsave(&clockfw_lock, flags);
 202         if (arch_clock->clk_set_parent)
 203                 ret = arch_clock->clk_set_parent(clk, parent);
 204         if (ret == 0 && (clk->flags & RATE_PROPAGATES))
 205                 propagate_rate(clk);
 206         spin_unlock_irqrestore(&clockfw_lock, flags);
 207
 208         return ret;
 209 }
 210 EXPORT_SYMBOL(clk_set_parent);
 211
 212 struct clk *clk_get_parent(struct clk *clk)
 213 {
 214         return clk->parent;
 215 }
 216 EXPORT_SYMBOL(clk_get_parent);
 217
 218 /*-------------------------------------------------------------------------
 219  * OMAP specific clock functions shared between omap1 and omap2
 220  *-------------------------------------------------------------------------*/
 221
 222 unsigned int __initdata mpurate;
 223
 224 /*
 225  * By default we use the rate set by the bootloader.
 226  * You can override this with mpurate= cmdline option.
 227  */
 228 static int __init omap_clk_setup(char *str)
 229 {
 230         get_option(&str, &mpurate);
 231
 232         if (!mpurate)
 233                 return 1;
 234
 235         if (mpurate < 1000)
 236                 mpurate *= 1000000;
 237
 238         return 1;
 239 }
 240 __setup("mpurate=", omap_clk_setup);
 241
 242 /* Used for clocks that always have same value as the parent clock */
 243 void followparent_recalc(struct clk *clk)
 244 {
 245         if (clk == NULL || IS_ERR(clk))
 246                 return;
 247
 248         clk->rate = clk->parent->rate;
 249         if (unlikely(clk->flags & RATE_PROPAGATES))
 250                 propagate_rate(clk);
 251 }
 252
 253 /* Propagate rate to children */
 254 void propagate_rate(struct clk * tclk)
 255 {
 256         struct clk *clkp;
 257
 258         if (tclk == NULL || IS_ERR(tclk))
 259                 return;
 260
 261         list_for_each_entry(clkp, &clocks, node) {
 262                 if (likely(clkp->parent != tclk))
 263                         continue;
 264                 if (likely((u32)clkp->recalc))
 265                         clkp->recalc(clkp);
 266         }
 267 }
 268
 269 /**
 270  * recalculate_root_clocks - recalculate and propagate all root clocks
 271  *
 272  * Recalculates all root clocks (clocks with no parent), which if the
 273  * clock's .recalc is set correctly, should also propagate their rates.
 274  * Called at init.
 275  */
 276 void recalculate_root_clocks(void)
 277 {
 278         struct clk *clkp;
 279
 280         list_for_each_entry(clkp, &clocks, node) {
 281                 if (unlikely(!clkp->parent) && likely((u32)clkp->recalc))
 282                         clkp->recalc(clkp);
 283         }
 284 }
 285
 286 int clk_register(struct clk *clk)
 287 {
 288         if (clk == NULL || IS_ERR(clk))
 289                 return -EINVAL;
 290
 291         mutex_lock(&clocks_mutex);
 292         list_add(&clk->node, &clocks);
 293         if (clk->init)
 294                 clk->init(clk);
 295         mutex_unlock(&clocks_mutex);
 296
 297         return 0;
 298 }
 299 EXPORT_SYMBOL(clk_register);
 300
 301 void clk_unregister(struct clk *clk)
 302 {
 303         if (clk == NULL || IS_ERR(clk))
 304                 return;
 305
 306         mutex_lock(&clocks_mutex);
 307         list_del(&clk->node);
 308         mutex_unlock(&clocks_mutex);
 309 }
 310 EXPORT_SYMBOL(clk_unregister);
 311
 312 void clk_enable_init_clocks(void)
 313 {
 314         struct clk *clkp;
 315
 316         list_for_each_entry(clkp, &clocks, node) {
 317                 if (clkp->flags & ENABLE_ON_INIT)
 318                         clk_enable(clkp);
 319         }
 320 }
 321 EXPORT_SYMBOL(clk_enable_init_clocks);
 322
 323 /*
 324  * Low level helpers
 325  */
 326 static int clkll_enable_null(struct clk *clk)
 327 {
 328         return 0;
 329 }
 330
 331 static void clkll_disable_null(struct clk *clk)
 332 {
 333 }
 334
 335 const struct clkops clkops_null = {
 336         .enable         = clkll_enable_null,
 337         .disable        = clkll_disable_null,
 338 };
 339
 340 #ifdef CONFIG_CPU_FREQ
 341 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 342 {
 343         unsigned long flags;
 344
 345         spin_lock_irqsave(&clockfw_lock, flags);
 346         if (arch_clock->clk_init_cpufreq_table)
 347                 arch_clock->clk_init_cpufreq_table(table);
 348         spin_unlock_irqrestore(&clockfw_lock, flags);
 349 }
 350 EXPORT_SYMBOL(clk_init_cpufreq_table);
 351 #endif
 352
 353 /*-------------------------------------------------------------------------*/
 354
 355 #ifdef CONFIG_OMAP_RESET_CLOCKS
 356 /*
 357  * Disable any unused clocks left on by the bootloader
 358  */
 359 static int __init clk_disable_unused(void)
 360 {
 361         struct clk *ck;
 362         unsigned long flags;
 363
 364         list_for_each_entry(ck, &clocks, node) {
 365                 if (ck->ops == &clkops_null)
 366                         continue;
 367
 368                 if (ck->usecount > 0 || ck->enable_reg == 0)
 369                         continue;
 370
 371                 spin_lock_irqsave(&clockfw_lock, flags);
 372                 if (arch_clock->clk_disable_unused)
 373                         arch_clock->clk_disable_unused(ck);
 374                 spin_unlock_irqrestore(&clockfw_lock, flags);
 375         }
 376
 377         return 0;
 378 }
 379 late_initcall(clk_disable_unused);
 380 #endif
 381
 382 int __init clk_init(struct clk_functions * custom_clocks)
 383 {
 384         if (!custom_clocks) {
 385                 printk(KERN_ERR "No custom clock functions registered\n");
 386                 BUG();
 387         }
 388
 389         arch_clock = custom_clocks;
 390
 391         return 0;
 392 }
 393
 394 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 395 /*
 396  *      debugfs support to trace clock tree hierarchy and attributes
 397  */
 398 static struct dentry *clk_debugfs_root;
 399
 400 static int clk_debugfs_register_one(struct clk *c)
 401 {
 402         int err;
 403         struct dentry *d, *child;
 404         struct clk *pa = c->parent;
 405         char s[255];
 406         char *p = s;
 407
 408         p += sprintf(p, "%s", c->name);
 409         if (c->id != 0)
 410                 sprintf(p, ":%d", c->id);
 411         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 412         if (!d)
 413                 return -ENOMEM;
 414         c->dent = d;
 415
 416         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 417         if (!d) {
 418                 err = -ENOMEM;
 419                 goto err_out;
 420         }
 421         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 422         if (!d) {
 423                 err = -ENOMEM;
 424                 goto err_out;
 425         }
 426         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 427         if (!d) {
 428                 err = -ENOMEM;
 429                 goto err_out;
 430         }
 431         return 0;
 432
 433 err_out:
 434         d = c->dent;
 435         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 436                 debugfs_remove(child);
 437         debugfs_remove(c->dent);
 438         return err;
 439 }
 440
 441 static int clk_debugfs_register(struct clk *c)
 442 {
 443         int err;
 444         struct clk *pa = c->parent;
 445
 446         if (pa && !pa->dent) {
 447                 err = clk_debugfs_register(pa);
 448                 if (err)
 449                         return err;
 450         }
 451
 452         if (!c->dent) {
 453                 err = clk_debugfs_register_one(c);
 454                 if (err)
 455                         return err;
 456         }
 457         return 0;
 458 }
 459
 460 static int __init clk_debugfs_init(void)
 461 {
 462         struct clk *c;
 463         struct dentry *d;
 464         int err;
 465
 466         d = debugfs_create_dir("clock", NULL);
 467         if (!d)
 468                 return -ENOMEM;
 469         clk_debugfs_root = d;
 470
 471         list_for_each_entry(c, &clocks, node) {
 472                 err = clk_debugfs_register(c);
 473                 if (err)
 474                         goto err_out;
 475         }
 476         return 0;
 477 err_out:
 478         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 479         return err;
 480 }
 481 late_initcall(clk_debugfs_init);
 482
 483 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */