arch/arm/plat-omap/clock.c

   1 /*
   2  *  linux/arch/arm/plat-omap/clock.c
   3  *
   4  *  Copyright (C) 2004 - 2005 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/version.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/list.h>
  18 #include <linux/errno.h>
  19 #include <linux/err.h>
  20 #include <linux/string.h>
  21 #include <linux/clk.h>
  22 #include <linux/mutex.h>
  23 #include <linux/platform_device.h>
  24
  25 #include <asm/io.h>
  26 #include <asm/semaphore.h>
  27
  28 #include <asm/arch/clock.h>
  29
  30 static LIST_HEAD(clocks);
  31 static DEFINE_MUTEX(clocks_mutex);
  32 static DEFINE_SPINLOCK(clockfw_lock);
  33
  34 static struct clk_functions *arch_clock;
  35
  36 /*-------------------------------------------------------------------------
  37  * Standard clock functions defined in include/linux/clk.h
  38  *-------------------------------------------------------------------------*/
  39
  40 /*
  41  * Returns a clock. Note that we first try to use device id on the bus
  42  * and clock name. If this fails, we try to use clock name only.
  43  */
  44 struct clk * clk_get(struct device *dev, const char *id)
  45 {
  46         struct clk *p, *clk = ERR_PTR(-ENOENT);
  47         int idno;
  48
  49         if (dev == NULL || dev->bus != &platform_bus_type)
  50                 idno = -1;
  51         else
  52                 idno = to_platform_device(dev)->id;
  53
  54         mutex_lock(&clocks_mutex);
  55
  56         list_for_each_entry(p, &clocks, node) {
  57                 if (p->id == idno &&
  58                     strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
  59                         clk = p;
  60                         goto found;
  61                 }
  62         }
  63
  64         list_for_each_entry(p, &clocks, node) {
  65                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
  66                         clk = p;
  67                         break;
  68                 }
  69         }
  70
  71 found:
  72         mutex_unlock(&clocks_mutex);
  73
  74         return clk;
  75 }
  76 EXPORT_SYMBOL(clk_get);
  77
  78 int clk_enable(struct clk *clk)
  79 {
  80         unsigned long flags;
  81         int ret = 0;
  82
  83         if (clk == NULL || IS_ERR(clk))
  84                 return -EINVAL;
  85
  86         spin_lock_irqsave(&clockfw_lock, flags);
  87         if (arch_clock->clk_enable)
  88                 ret = arch_clock->clk_enable(clk);
  89         spin_unlock_irqrestore(&clockfw_lock, flags);
  90
  91         return ret;
  92 }
  93 EXPORT_SYMBOL(clk_enable);
  94
  95 void clk_disable(struct clk *clk)
  96 {
  97         unsigned long flags;
  98
  99         if (clk == NULL || IS_ERR(clk))
 100                 return;
 101
 102         spin_lock_irqsave(&clockfw_lock, flags);
 103         BUG_ON(clk->usecount == 0);
 104         if (arch_clock->clk_disable)
 105                 arch_clock->clk_disable(clk);
 106         spin_unlock_irqrestore(&clockfw_lock, flags);
 107 }
 108 EXPORT_SYMBOL(clk_disable);
 109
 110 int clk_get_usecount(struct clk *clk)
 111 {
 112         unsigned long flags;
 113         int ret = 0;
 114
 115         if (clk == NULL || IS_ERR(clk))
 116                 return 0;
 117
 118         spin_lock_irqsave(&clockfw_lock, flags);
 119         ret = clk->usecount;
 120         spin_unlock_irqrestore(&clockfw_lock, flags);
 121
 122         return ret;
 123 }
 124 EXPORT_SYMBOL(clk_get_usecount);
 125
 126 unsigned long clk_get_rate(struct clk *clk)
 127 {
 128         unsigned long flags;
 129         unsigned long ret = 0;
 130
 131         if (clk == NULL || IS_ERR(clk))
 132                 return 0;
 133
 134         spin_lock_irqsave(&clockfw_lock, flags);
 135         ret = clk->rate;
 136         spin_unlock_irqrestore(&clockfw_lock, flags);
 137
 138         return ret;
 139 }
 140 EXPORT_SYMBOL(clk_get_rate);
 141
 142 void clk_put(struct clk *clk)
 143 {
 144         if (clk && !IS_ERR(clk))
 145                 module_put(clk->owner);
 146 }
 147 EXPORT_SYMBOL(clk_put);
 148
 149 /*-------------------------------------------------------------------------
 150  * Optional clock functions defined in include/linux/clk.h
 151  *-------------------------------------------------------------------------*/
 152
 153 long clk_round_rate(struct clk *clk, unsigned long rate)
 154 {
 155         unsigned long flags;
 156         long ret = 0;
 157
 158         if (clk == NULL || IS_ERR(clk))
 159                 return ret;
 160
 161         spin_lock_irqsave(&clockfw_lock, flags);
 162         if (arch_clock->clk_round_rate)
 163                 ret = arch_clock->clk_round_rate(clk, rate);
 164         spin_unlock_irqrestore(&clockfw_lock, flags);
 165
 166         return ret;
 167 }
 168 EXPORT_SYMBOL(clk_round_rate);
 169
 170 int clk_set_rate(struct clk *clk, unsigned long rate)
 171 {
 172         unsigned long flags;
 173         int ret = -EINVAL;
 174
 175         if (clk == NULL || IS_ERR(clk))
 176                 return ret;
 177
 178         spin_lock_irqsave(&clockfw_lock, flags);
 179         if (arch_clock->clk_set_rate)
 180                 ret = arch_clock->clk_set_rate(clk, rate);
 181         spin_unlock_irqrestore(&clockfw_lock, flags);
 182
 183         return ret;
 184 }
 185 EXPORT_SYMBOL(clk_set_rate);
 186
 187 int clk_set_parent(struct clk *clk, struct clk *parent)
 188 {
 189         unsigned long flags;
 190         int ret = -EINVAL;
 191
 192         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 193                 return ret;
 194
 195         spin_lock_irqsave(&clockfw_lock, flags);
 196         if (arch_clock->clk_set_parent)
 197                 ret =  arch_clock->clk_set_parent(clk, parent);
 198         spin_unlock_irqrestore(&clockfw_lock, flags);
 199
 200         return ret;
 201 }
 202 EXPORT_SYMBOL(clk_set_parent);
 203
 204 struct clk *clk_get_parent(struct clk *clk)
 205 {
 206         unsigned long flags;
 207         struct clk * ret = NULL;
 208
 209         if (clk == NULL || IS_ERR(clk))
 210                 return ret;
 211
 212         spin_lock_irqsave(&clockfw_lock, flags);
 213         if (arch_clock->clk_get_parent)
 214                 ret = arch_clock->clk_get_parent(clk);
 215         spin_unlock_irqrestore(&clockfw_lock, flags);
 216
 217         return ret;
 218 }
 219 EXPORT_SYMBOL(clk_get_parent);
 220
 221 /*-------------------------------------------------------------------------
 222  * OMAP specific clock functions shared between omap1 and omap2
 223  *-------------------------------------------------------------------------*/
 224
 225 unsigned int __initdata mpurate;
 226
 227 /*
 228  * By default we use the rate set by the bootloader.
 229  * You can override this with mpurate= cmdline option.
 230  */
 231 static int __init omap_clk_setup(char *str)
 232 {
 233         get_option(&str, &mpurate);
 234
 235         if (!mpurate)
 236                 return 1;
 237
 238         if (mpurate < 1000)
 239                 mpurate *= 1000000;
 240
 241         return 1;
 242 }
 243 __setup("mpurate=", omap_clk_setup);
 244
 245 /* Used for clocks that always have same value as the parent clock */
 246 void followparent_recalc(struct clk *clk)
 247 {
 248         if (clk == NULL || IS_ERR(clk))
 249                 return;
 250
 251         clk->rate = clk->parent->rate;
 252 }
 253
 254 /* Propagate rate to children */
 255 void propagate_rate(struct clk * tclk)
 256 {
 257         struct clk *clkp;
 258
 259         if (tclk == NULL || IS_ERR(tclk))
 260                 return;
 261
 262         list_for_each_entry(clkp, &clocks, node) {
 263                 if (likely(clkp->parent != tclk))
 264                         continue;
 265                 if (likely((u32)clkp->recalc))
 266                         clkp->recalc(clkp);
 267         }
 268 }
 269
 270 int clk_register(struct clk *clk)
 271 {
 272         if (clk == NULL || IS_ERR(clk))
 273                 return -EINVAL;
 274
 275         mutex_lock(&clocks_mutex);
 276         list_add(&clk->node, &clocks);
 277         if (clk->init)
 278                 clk->init(clk);
 279         mutex_unlock(&clocks_mutex);
 280
 281         return 0;
 282 }
 283 EXPORT_SYMBOL(clk_register);
 284
 285 void clk_unregister(struct clk *clk)
 286 {
 287         if (clk == NULL || IS_ERR(clk))
 288                 return;
 289
 290         mutex_lock(&clocks_mutex);
 291         list_del(&clk->node);
 292         mutex_unlock(&clocks_mutex);
 293 }
 294 EXPORT_SYMBOL(clk_unregister);
 295
 296 void clk_deny_idle(struct clk *clk)
 297 {
 298         unsigned long flags;
 299
 300         if (clk == NULL || IS_ERR(clk))
 301                 return;
 302
 303         spin_lock_irqsave(&clockfw_lock, flags);
 304         if (arch_clock->clk_deny_idle)
 305                 arch_clock->clk_deny_idle(clk);
 306         spin_unlock_irqrestore(&clockfw_lock, flags);
 307 }
 308 EXPORT_SYMBOL(clk_deny_idle);
 309
 310 void clk_allow_idle(struct clk *clk)
 311 {
 312         unsigned long flags;
 313
 314         if (clk == NULL || IS_ERR(clk))
 315                 return;
 316
 317         spin_lock_irqsave(&clockfw_lock, flags);
 318         if (arch_clock->clk_allow_idle)
 319                 arch_clock->clk_allow_idle(clk);
 320         spin_unlock_irqrestore(&clockfw_lock, flags);
 321 }
 322 EXPORT_SYMBOL(clk_allow_idle);
 323
 324 /*-------------------------------------------------------------------------*/
 325
 326 #ifdef CONFIG_OMAP_RESET_CLOCKS
 327 /*
 328  * Disable any unused clocks left on by the bootloader
 329  */
 330 static int __init clk_disable_unused(void)
 331 {
 332         struct clk *ck;
 333         unsigned long flags;
 334
 335         list_for_each_entry(ck, &clocks, node) {
 336                 if (ck->usecount > 0 || (ck->flags & ALWAYS_ENABLED) ||
 337                         ck->enable_reg == 0)
 338                         continue;
 339
 340                 spin_lock_irqsave(&clockfw_lock, flags);
 341                 if (arch_clock->clk_disable_unused)
 342                         arch_clock->clk_disable_unused(ck);
 343                 spin_unlock_irqrestore(&clockfw_lock, flags);
 344         }
 345
 346         return 0;
 347 }
 348 late_initcall(clk_disable_unused);
 349 #endif
 350
 351 int __init clk_init(struct clk_functions * custom_clocks)
 352 {
 353         if (!custom_clocks) {
 354                 printk(KERN_ERR "No custom clock functions registered\n");
 355                 BUG();
 356         }
 357
 358         arch_clock = custom_clocks;
 359
 360         return 0;
 361 }