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 }
 250
 251 /* Propagate rate to children */
 252 void propagate_rate(struct clk * tclk)
 253 {
 254         struct clk *clkp;
 255
 256         if (tclk == NULL || IS_ERR(tclk))
 257                 return;
 258
 259         list_for_each_entry(clkp, &clocks, node) {
 260                 if (likely(clkp->parent != tclk))
 261                         continue;
 262                 if (clkp->recalc)
 263                         clkp->recalc(clkp);
 264                 if (clkp->flags & RATE_PROPAGATES)
 265                         propagate_rate(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 (!clkp->parent) {
 282                         if (clkp->recalc)
 283                                 clkp->recalc(clkp);
 284                         if (clkp->flags & RATE_PROPAGATES)
 285                                 propagate_rate(clkp);
 286                 }
 287         }
 288 }
 289
 290 int clk_register(struct clk *clk)
 291 {
 292         if (clk == NULL || IS_ERR(clk))
 293                 return -EINVAL;
 294
 295         /*
 296          * trap out already registered clocks
 297          */
 298         if (clk->node.next || clk->node.prev)
 299                 return 0;
 300
 301         mutex_lock(&clocks_mutex);
 302         list_add(&clk->node, &clocks);
 303         if (clk->init)
 304                 clk->init(clk);
 305         mutex_unlock(&clocks_mutex);
 306
 307         return 0;
 308 }
 309 EXPORT_SYMBOL(clk_register);
 310
 311 void clk_unregister(struct clk *clk)
 312 {
 313         if (clk == NULL || IS_ERR(clk))
 314                 return;
 315
 316         mutex_lock(&clocks_mutex);
 317         list_del(&clk->node);
 318         mutex_unlock(&clocks_mutex);
 319 }
 320 EXPORT_SYMBOL(clk_unregister);
 321
 322 void clk_enable_init_clocks(void)
 323 {
 324         struct clk *clkp;
 325
 326         list_for_each_entry(clkp, &clocks, node) {
 327                 if (clkp->flags & ENABLE_ON_INIT)
 328                         clk_enable(clkp);
 329         }
 330 }
 331 EXPORT_SYMBOL(clk_enable_init_clocks);
 332
 333 /*
 334  * Low level helpers
 335  */
 336 static int clkll_enable_null(struct clk *clk)
 337 {
 338         return 0;
 339 }
 340
 341 static void clkll_disable_null(struct clk *clk)
 342 {
 343 }
 344
 345 const struct clkops clkops_null = {
 346         .enable         = clkll_enable_null,
 347         .disable        = clkll_disable_null,
 348 };
 349
 350 #ifdef CONFIG_CPU_FREQ
 351 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 352 {
 353         unsigned long flags;
 354
 355         spin_lock_irqsave(&clockfw_lock, flags);
 356         if (arch_clock->clk_init_cpufreq_table)
 357                 arch_clock->clk_init_cpufreq_table(table);
 358         spin_unlock_irqrestore(&clockfw_lock, flags);
 359 }
 360 EXPORT_SYMBOL(clk_init_cpufreq_table);
 361 #endif
 362
 363 /*-------------------------------------------------------------------------*/
 364
 365 #ifdef CONFIG_OMAP_RESET_CLOCKS
 366 /*
 367  * Disable any unused clocks left on by the bootloader
 368  */
 369 static int __init clk_disable_unused(void)
 370 {
 371         struct clk *ck;
 372         unsigned long flags;
 373
 374         list_for_each_entry(ck, &clocks, node) {
 375                 if (ck->ops == &clkops_null)
 376                         continue;
 377
 378                 if (ck->usecount > 0 || ck->enable_reg == 0)
 379                         continue;
 380
 381                 spin_lock_irqsave(&clockfw_lock, flags);
 382                 if (arch_clock->clk_disable_unused)
 383                         arch_clock->clk_disable_unused(ck);
 384                 spin_unlock_irqrestore(&clockfw_lock, flags);
 385         }
 386
 387         return 0;
 388 }
 389 late_initcall(clk_disable_unused);
 390 #endif
 391
 392 int __init clk_init(struct clk_functions * custom_clocks)
 393 {
 394         if (!custom_clocks) {
 395                 printk(KERN_ERR "No custom clock functions registered\n");
 396                 BUG();
 397         }
 398
 399         arch_clock = custom_clocks;
 400
 401         return 0;
 402 }
 403
 404 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 405 /*
 406  *      debugfs support to trace clock tree hierarchy and attributes
 407  */
 408 static struct dentry *clk_debugfs_root;
 409
 410 static int clk_debugfs_register_one(struct clk *c)
 411 {
 412         int err;
 413         struct dentry *d, *child;
 414         struct clk *pa = c->parent;
 415         char s[255];
 416         char *p = s;
 417
 418         p += sprintf(p, "%s", c->name);
 419         if (c->id != 0)
 420                 sprintf(p, ":%d", c->id);
 421         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 422         if (!d)
 423                 return -ENOMEM;
 424         c->dent = d;
 425
 426         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 427         if (!d) {
 428                 err = -ENOMEM;
 429                 goto err_out;
 430         }
 431         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 432         if (!d) {
 433                 err = -ENOMEM;
 434                 goto err_out;
 435         }
 436         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 437         if (!d) {
 438                 err = -ENOMEM;
 439                 goto err_out;
 440         }
 441         return 0;
 442
 443 err_out:
 444         d = c->dent;
 445         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 446                 debugfs_remove(child);
 447         debugfs_remove(c->dent);
 448         return err;
 449 }
 450
 451 static int clk_debugfs_register(struct clk *c)
 452 {
 453         int err;
 454         struct clk *pa = c->parent;
 455
 456         if (pa && !pa->dent) {
 457                 err = clk_debugfs_register(pa);
 458                 if (err)
 459                         return err;
 460         }
 461
 462         if (!c->dent) {
 463                 err = clk_debugfs_register_one(c);
 464                 if (err)
 465                         return err;
 466         }
 467         return 0;
 468 }
 469
 470 static int __init clk_debugfs_init(void)
 471 {
 472         struct clk *c;
 473         struct dentry *d;
 474         int err;
 475
 476         d = debugfs_create_dir("clock", NULL);
 477         if (!d)
 478                 return -ENOMEM;
 479         clk_debugfs_root = d;
 480
 481         list_for_each_entry(c, &clocks, node) {
 482                 err = clk_debugfs_register(c);
 483                 if (err)
 484                         goto err_out;
 485         }
 486         return 0;
 487 err_out:
 488         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 489         return err;
 490 }
 491 late_initcall(clk_debugfs_init);
 492
 493 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */