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         if (arch_clock->clk_disable)
 104                 arch_clock->clk_disable(clk);
 105         spin_unlock_irqrestore(&clockfw_lock, flags);
 106 }
 107 EXPORT_SYMBOL(clk_disable);
 108
 109 int clk_get_usecount(struct clk *clk)
 110 {
 111         unsigned long flags;
 112         int ret = 0;
 113
 114         if (clk == NULL || IS_ERR(clk))
 115                 return 0;
 116
 117         spin_lock_irqsave(&clockfw_lock, flags);
 118         ret = clk->usecount;
 119         spin_unlock_irqrestore(&clockfw_lock, flags);
 120
 121         return ret;
 122 }
 123 EXPORT_SYMBOL(clk_get_usecount);
 124
 125 unsigned long clk_get_rate(struct clk *clk)
 126 {
 127         unsigned long flags;
 128         unsigned long ret = 0;
 129
 130         if (clk == NULL || IS_ERR(clk))
 131                 return 0;
 132
 133         spin_lock_irqsave(&clockfw_lock, flags);
 134         ret = clk->rate;
 135         spin_unlock_irqrestore(&clockfw_lock, flags);
 136
 137         return ret;
 138 }
 139 EXPORT_SYMBOL(clk_get_rate);
 140
 141 void clk_put(struct clk *clk)
 142 {
 143         if (clk && !IS_ERR(clk))
 144                 module_put(clk->owner);
 145 }
 146 EXPORT_SYMBOL(clk_put);
 147
 148 /*-------------------------------------------------------------------------
 149  * Optional clock functions defined in include/linux/clk.h
 150  *-------------------------------------------------------------------------*/
 151
 152 long clk_round_rate(struct clk *clk, unsigned long rate)
 153 {
 154         unsigned long flags;
 155         long ret = 0;
 156
 157         if (clk == NULL || IS_ERR(clk))
 158                 return ret;
 159
 160         spin_lock_irqsave(&clockfw_lock, flags);
 161         if (arch_clock->clk_round_rate)
 162                 ret = arch_clock->clk_round_rate(clk, rate);
 163         spin_unlock_irqrestore(&clockfw_lock, flags);
 164
 165         return ret;
 166 }
 167 EXPORT_SYMBOL(clk_round_rate);
 168
 169 int clk_set_rate(struct clk *clk, unsigned long rate)
 170 {
 171         unsigned long flags;
 172         int ret = -EINVAL;
 173
 174         if (clk == NULL || IS_ERR(clk))
 175                 return ret;
 176
 177         spin_lock_irqsave(&clockfw_lock, flags);
 178         if (arch_clock->clk_set_rate)
 179                 ret = arch_clock->clk_set_rate(clk, rate);
 180         spin_unlock_irqrestore(&clockfw_lock, flags);
 181
 182         return ret;
 183 }
 184 EXPORT_SYMBOL(clk_set_rate);
 185
 186 int clk_set_parent(struct clk *clk, struct clk *parent)
 187 {
 188         unsigned long flags;
 189         int ret = -EINVAL;
 190
 191         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 192                 return ret;
 193
 194         spin_lock_irqsave(&clockfw_lock, flags);
 195         if (arch_clock->clk_set_parent)
 196                 ret =  arch_clock->clk_set_parent(clk, parent);
 197         spin_unlock_irqrestore(&clockfw_lock, flags);
 198
 199         return ret;
 200 }
 201 EXPORT_SYMBOL(clk_set_parent);
 202
 203 struct clk *clk_get_parent(struct clk *clk)
 204 {
 205         unsigned long flags;
 206         struct clk * ret = NULL;
 207
 208         if (clk == NULL || IS_ERR(clk))
 209                 return ret;
 210
 211         spin_lock_irqsave(&clockfw_lock, flags);
 212         if (arch_clock->clk_get_parent)
 213                 ret = arch_clock->clk_get_parent(clk);
 214         spin_unlock_irqrestore(&clockfw_lock, flags);
 215
 216         return ret;
 217 }
 218 EXPORT_SYMBOL(clk_get_parent);
 219
 220 /*-------------------------------------------------------------------------
 221  * OMAP specific clock functions shared between omap1 and omap2
 222  *-------------------------------------------------------------------------*/
 223
 224 unsigned int __initdata mpurate;
 225
 226 /*
 227  * By default we use the rate set by the bootloader.
 228  * You can override this with mpurate= cmdline option.
 229  */
 230 static int __init omap_clk_setup(char *str)
 231 {
 232         get_option(&str, &mpurate);
 233
 234         if (!mpurate)
 235                 return 1;
 236
 237         if (mpurate < 1000)
 238                 mpurate *= 1000000;
 239
 240         return 1;
 241 }
 242 __setup("mpurate=", omap_clk_setup);
 243
 244 /* Used for clocks that always have same value as the parent clock */
 245 void followparent_recalc(struct clk *clk)
 246 {
 247         if (clk == NULL || IS_ERR(clk))
 248                 return;
 249
 250         clk->rate = clk->parent->rate;
 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 int clk_register(struct clk *clk)
 270 {
 271         if (clk == NULL || IS_ERR(clk))
 272                 return -EINVAL;
 273
 274         mutex_lock(&clocks_mutex);
 275         list_add(&clk->node, &clocks);
 276         if (clk->init)
 277                 clk->init(clk);
 278         mutex_unlock(&clocks_mutex);
 279
 280         return 0;
 281 }
 282 EXPORT_SYMBOL(clk_register);
 283
 284 void clk_unregister(struct clk *clk)
 285 {
 286         if (clk == NULL || IS_ERR(clk))
 287                 return;
 288
 289         mutex_lock(&clocks_mutex);
 290         list_del(&clk->node);
 291         mutex_unlock(&clocks_mutex);
 292 }
 293 EXPORT_SYMBOL(clk_unregister);
 294
 295 void clk_deny_idle(struct clk *clk)
 296 {
 297         unsigned long flags;
 298
 299         if (clk == NULL || IS_ERR(clk))
 300                 return;
 301
 302         spin_lock_irqsave(&clockfw_lock, flags);
 303         if (arch_clock->clk_deny_idle)
 304                 arch_clock->clk_deny_idle(clk);
 305         spin_unlock_irqrestore(&clockfw_lock, flags);
 306 }
 307 EXPORT_SYMBOL(clk_deny_idle);
 308
 309 void clk_allow_idle(struct clk *clk)
 310 {
 311         unsigned long flags;
 312
 313         if (clk == NULL || IS_ERR(clk))
 314                 return;
 315
 316         spin_lock_irqsave(&clockfw_lock, flags);
 317         if (arch_clock->clk_allow_idle)
 318                 arch_clock->clk_allow_idle(clk);
 319         spin_unlock_irqrestore(&clockfw_lock, flags);
 320 }
 321 EXPORT_SYMBOL(clk_allow_idle);
 322
 323 /*-------------------------------------------------------------------------*/
 324
 325 int __init clk_init(struct clk_functions * custom_clocks)
 326 {
 327         if (!custom_clocks) {
 328                 printk(KERN_ERR "No custom clock functions registered\n");
 329                 BUG();
 330         }
 331
 332         arch_clock = custom_clocks;
 333
 334         return 0;
 335 }