arch/arm/plat-mxc/clock.c

   1 /*
   2  * Based on arch/arm/plat-omap/clock.c
   3  *
   4  * Copyright (C) 2004 - 2005 Nokia corporation
   5  * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
   6  * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
   7  * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
   8  * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  22  * MA  02110-1301, USA.
  23  */
  24
  25 /* #define DEBUG */
  26
  27 #include <linux/clk.h>
  28 #include <linux/err.h>
  29 #include <linux/errno.h>
  30 #include <linux/init.h>
  31 #include <linux/io.h>
  32 #include <linux/kernel.h>
  33 #include <linux/list.h>
  34 #include <linux/module.h>
  35 #include <linux/mutex.h>
  36 #include <linux/platform_device.h>
  37 #include <linux/proc_fs.h>
  38 #include <linux/semaphore.h>
  39 #include <linux/string.h>
  40
  41 #include <mach/clock.h>
  42
  43 static LIST_HEAD(clocks);
  44 static DEFINE_MUTEX(clocks_mutex);
  45
  46 /*-------------------------------------------------------------------------
  47  * Standard clock functions defined in include/linux/clk.h
  48  *-------------------------------------------------------------------------*/
  49
  50 /*
  51  * All the code inside #ifndef CONFIG_COMMON_CLKDEV can be removed once all
  52  * MXC architectures have switched to using clkdev.
  53  */
  54 #ifndef CONFIG_COMMON_CLKDEV
  55 /*
  56  * Retrieve a clock by name.
  57  *
  58  * Note that we first try to use device id on the bus
  59  * and clock name. If this fails, we try to use "<name>.<id>". If this fails,
  60  * we try to use clock name only.
  61  * The reference count to the clock's module owner ref count is incremented.
  62  */
  63 struct clk *clk_get(struct device *dev, const char *id)
  64 {
  65         struct clk *p, *clk = ERR_PTR(-ENOENT);
  66         int idno;
  67         const char *str;
  68
  69         if (id == NULL)
  70                 return clk;
  71
  72         if (dev == NULL || dev->bus != &platform_bus_type)
  73                 idno = -1;
  74         else
  75                 idno = to_platform_device(dev)->id;
  76
  77         mutex_lock(&clocks_mutex);
  78
  79         list_for_each_entry(p, &clocks, node) {
  80                 if (p->id == idno &&
  81                     strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
  82                         clk = p;
  83                         goto found;
  84                 }
  85         }
  86
  87         str = strrchr(id, '.');
  88         if (str) {
  89                 int cnt = str - id;
  90                 str++;
  91                 idno = simple_strtol(str, NULL, 10);
  92                 list_for_each_entry(p, &clocks, node) {
  93                         if (p->id == idno &&
  94                             strlen(p->name) == cnt &&
  95                             strncmp(id, p->name, cnt) == 0 &&
  96                             try_module_get(p->owner)) {
  97                                 clk = p;
  98                                 goto found;
  99                         }
 100                 }
 101         }
 102
 103         list_for_each_entry(p, &clocks, node) {
 104                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 105                         clk = p;
 106                         goto found;
 107                 }
 108         }
 109
 110         printk(KERN_WARNING "clk: Unable to get requested clock: %s\n", id);
 111
 112 found:
 113         mutex_unlock(&clocks_mutex);
 114
 115         return clk;
 116 }
 117 EXPORT_SYMBOL(clk_get);
 118 #endif
 119
 120 static void __clk_disable(struct clk *clk)
 121 {
 122         if (clk == NULL || IS_ERR(clk))
 123                 return;
 124
 125         __clk_disable(clk->parent);
 126         __clk_disable(clk->secondary);
 127
 128         if (!(--clk->usecount) && clk->disable)
 129                 clk->disable(clk);
 130 }
 131
 132 static int __clk_enable(struct clk *clk)
 133 {
 134         if (clk == NULL || IS_ERR(clk))
 135                 return -EINVAL;
 136
 137         __clk_enable(clk->parent);
 138         __clk_enable(clk->secondary);
 139
 140         if (clk->usecount++ == 0 && clk->enable)
 141                 clk->enable(clk);
 142
 143         return 0;
 144 }
 145
 146 /* This function increments the reference count on the clock and enables the
 147  * clock if not already enabled. The parent clock tree is recursively enabled
 148  */
 149 int clk_enable(struct clk *clk)
 150 {
 151         int ret = 0;
 152
 153         if (clk == NULL || IS_ERR(clk))
 154                 return -EINVAL;
 155
 156         mutex_lock(&clocks_mutex);
 157         ret = __clk_enable(clk);
 158         mutex_unlock(&clocks_mutex);
 159
 160         return ret;
 161 }
 162 EXPORT_SYMBOL(clk_enable);
 163
 164 /* This function decrements the reference count on the clock and disables
 165  * the clock when reference count is 0. The parent clock tree is
 166  * recursively disabled
 167  */
 168 void clk_disable(struct clk *clk)
 169 {
 170         if (clk == NULL || IS_ERR(clk))
 171                 return;
 172
 173         mutex_lock(&clocks_mutex);
 174         __clk_disable(clk);
 175         mutex_unlock(&clocks_mutex);
 176 }
 177 EXPORT_SYMBOL(clk_disable);
 178
 179 /* Retrieve the *current* clock rate. If the clock itself
 180  * does not provide a special calculation routine, ask
 181  * its parent and so on, until one is able to return
 182  * a valid clock rate
 183  */
 184 unsigned long clk_get_rate(struct clk *clk)
 185 {
 186         if (clk == NULL || IS_ERR(clk))
 187                 return 0UL;
 188
 189         if (clk->get_rate)
 190                 return clk->get_rate(clk);
 191
 192         return clk_get_rate(clk->parent);
 193 }
 194 EXPORT_SYMBOL(clk_get_rate);
 195
 196 #ifndef CONFIG_COMMON_CLKDEV
 197 /* Decrement the clock's module reference count */
 198 void clk_put(struct clk *clk)
 199 {
 200         if (clk && !IS_ERR(clk))
 201                 module_put(clk->owner);
 202 }
 203 EXPORT_SYMBOL(clk_put);
 204 #endif
 205
 206 /* Round the requested clock rate to the nearest supported
 207  * rate that is less than or equal to the requested rate.
 208  * This is dependent on the clock's current parent.
 209  */
 210 long clk_round_rate(struct clk *clk, unsigned long rate)
 211 {
 212         if (clk == NULL || IS_ERR(clk) || !clk->round_rate)
 213                 return 0;
 214
 215         return clk->round_rate(clk, rate);
 216 }
 217 EXPORT_SYMBOL(clk_round_rate);
 218
 219 /* Set the clock to the requested clock rate. The rate must
 220  * match a supported rate exactly based on what clk_round_rate returns
 221  */
 222 int clk_set_rate(struct clk *clk, unsigned long rate)
 223 {
 224         int ret = -EINVAL;
 225
 226         if (clk == NULL || IS_ERR(clk) || clk->set_rate == NULL || rate == 0)
 227                 return ret;
 228
 229         mutex_lock(&clocks_mutex);
 230         ret = clk->set_rate(clk, rate);
 231         mutex_unlock(&clocks_mutex);
 232
 233         return ret;
 234 }
 235 EXPORT_SYMBOL(clk_set_rate);
 236
 237 /* Set the clock's parent to another clock source */
 238 int clk_set_parent(struct clk *clk, struct clk *parent)
 239 {
 240         int ret = -EINVAL;
 241
 242         if (clk == NULL || IS_ERR(clk) || parent == NULL ||
 243             IS_ERR(parent) || clk->set_parent == NULL)
 244                 return ret;
 245
 246         mutex_lock(&clocks_mutex);
 247         ret = clk->set_parent(clk, parent);
 248         if (ret == 0)
 249                 clk->parent = parent;
 250         mutex_unlock(&clocks_mutex);
 251
 252         return ret;
 253 }
 254 EXPORT_SYMBOL(clk_set_parent);
 255
 256 /* Retrieve the clock's parent clock source */
 257 struct clk *clk_get_parent(struct clk *clk)
 258 {
 259         struct clk *ret = NULL;
 260
 261         if (clk == NULL || IS_ERR(clk))
 262                 return ret;
 263
 264         return clk->parent;
 265 }
 266 EXPORT_SYMBOL(clk_get_parent);
 267
 268 #ifndef CONFIG_COMMON_CLKDEV
 269 /*
 270  * Add a new clock to the clock tree.
 271  */
 272 int clk_register(struct clk *clk)
 273 {
 274         if (clk == NULL || IS_ERR(clk))
 275                 return -EINVAL;
 276
 277         mutex_lock(&clocks_mutex);
 278         list_add(&clk->node, &clocks);
 279         mutex_unlock(&clocks_mutex);
 280
 281         return 0;
 282 }
 283 EXPORT_SYMBOL(clk_register);
 284
 285 /* Remove a clock from the clock tree */
 286 void clk_unregister(struct clk *clk)
 287 {
 288         if (clk == NULL || IS_ERR(clk))
 289                 return;
 290
 291         mutex_lock(&clocks_mutex);
 292         list_del(&clk->node);
 293         mutex_unlock(&clocks_mutex);
 294 }
 295 EXPORT_SYMBOL(clk_unregister);
 296
 297 #ifdef CONFIG_PROC_FS
 298 static int mxc_clock_read_proc(char *page, char **start, off_t off,
 299                                 int count, int *eof, void *data)
 300 {
 301         struct clk *clkp;
 302         char *p = page;
 303         int len;
 304
 305         list_for_each_entry(clkp, &clocks, node) {
 306                 p += sprintf(p, "%s-%d:\t\t%lu, %d", clkp->name, clkp->id,
 307                                 clk_get_rate(clkp), clkp->usecount);
 308                 if (clkp->parent)
 309                         p += sprintf(p, ", %s-%d\n", clkp->parent->name,
 310                                      clkp->parent->id);
 311                 else
 312                         p += sprintf(p, "\n");
 313         }
 314
 315         len = (p - page) - off;
 316         if (len < 0)
 317                 len = 0;
 318
 319         *eof = (len <= count) ? 1 : 0;
 320         *start = page + off;
 321
 322         return len;
 323 }
 324
 325 static int __init mxc_setup_proc_entry(void)
 326 {
 327         struct proc_dir_entry *res;
 328
 329         res = create_proc_read_entry("cpu/clocks", 0, NULL,
 330                                      mxc_clock_read_proc, NULL);
 331         if (!res) {
 332                 printk(KERN_ERR "Failed to create proc/cpu/clocks\n");
 333                 return -ENOMEM;
 334         }
 335         return 0;
 336 }
 337
 338 late_initcall(mxc_setup_proc_entry);
 339 #endif /* CONFIG_PROC_FS */
 340 #endif
 341
 342 /*
 343  * Get the resulting clock rate from a PLL register value and the input
 344  * frequency. PLLs with this register layout can at least be found on
 345  * MX1, MX21, MX27 and MX31
 346  *
 347  *                  mfi + mfn / (mfd + 1)
 348  *  f = 2 * f_ref * --------------------
 349  *                        pd + 1
 350  */
 351 unsigned long mxc_decode_pll(unsigned int reg_val, u32 freq)
 352 {
 353         long long ll;
 354         int mfn_abs;
 355         unsigned int mfi, mfn, mfd, pd;
 356
 357         mfi = (reg_val >> 10) & 0xf;
 358         mfn = reg_val & 0x3ff;
 359         mfd = (reg_val >> 16) & 0x3ff;
 360         pd =  (reg_val >> 26) & 0xf;
 361
 362         mfi = mfi <= 5 ? 5 : mfi;
 363
 364         mfn_abs = mfn;
 365
 366 #if !defined CONFIG_ARCH_MX1 && !defined CONFIG_ARCH_MX21
 367         if (mfn >= 0x200) {
 368                 mfn |= 0xFFFFFE00;
 369                 mfn_abs = -mfn;
 370         }
 371 #endif
 372
 373         freq *= 2;
 374         freq /= pd + 1;
 375
 376         ll = (unsigned long long)freq * mfn_abs;
 377
 378         do_div(ll, mfd + 1);
 379         if (mfn < 0)
 380                 ll = -ll;
 381         ll = (freq * mfi) + ll;
 382
 383         return ll;
 384 }