Juergen Beisert | c0db2ea | 2008-07-05 10:02:47 +0200 | [diff] [blame] | 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> |
Juergen Beisert | c0db2ea | 2008-07-05 10:02:47 +0200 | [diff] [blame] | 40 | |
Russell King | a09e64f | 2008-08-05 16:14:15 +0100 | [diff] [blame] | 41 | #include <mach/clock.h> |
Juergen Beisert | c0db2ea | 2008-07-05 10:02:47 +0200 | [diff] [blame] | 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 | * Retrieve a clock by name. |
| 52 | * |
| 53 | * Note that we first try to use device id on the bus |
| 54 | * and clock name. If this fails, we try to use "<name>.<id>". If this fails, |
| 55 | * we try to use clock name only. |
| 56 | * The reference count to the clock's module owner ref count is incremented. |
| 57 | */ |
| 58 | struct clk *clk_get(struct device *dev, const char *id) |
| 59 | { |
| 60 | struct clk *p, *clk = ERR_PTR(-ENOENT); |
| 61 | int idno; |
| 62 | const char *str; |
| 63 | |
| 64 | if (id == NULL) |
| 65 | return clk; |
| 66 | |
| 67 | if (dev == NULL || dev->bus != &platform_bus_type) |
| 68 | idno = -1; |
| 69 | else |
| 70 | idno = to_platform_device(dev)->id; |
| 71 | |
| 72 | mutex_lock(&clocks_mutex); |
| 73 | |
| 74 | list_for_each_entry(p, &clocks, node) { |
| 75 | if (p->id == idno && |
| 76 | strcmp(id, p->name) == 0 && try_module_get(p->owner)) { |
| 77 | clk = p; |
| 78 | goto found; |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | str = strrchr(id, '.'); |
| 83 | if (str) { |
| 84 | int cnt = str - id; |
| 85 | str++; |
| 86 | idno = simple_strtol(str, NULL, 10); |
| 87 | list_for_each_entry(p, &clocks, node) { |
| 88 | if (p->id == idno && |
| 89 | strlen(p->name) == cnt && |
| 90 | strncmp(id, p->name, cnt) == 0 && |
| 91 | try_module_get(p->owner)) { |
| 92 | clk = p; |
| 93 | goto found; |
| 94 | } |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | list_for_each_entry(p, &clocks, node) { |
| 99 | if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) { |
| 100 | clk = p; |
| 101 | goto found; |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | printk(KERN_WARNING "clk: Unable to get requested clock: %s\n", id); |
| 106 | |
| 107 | found: |
| 108 | mutex_unlock(&clocks_mutex); |
| 109 | |
| 110 | return clk; |
| 111 | } |
| 112 | EXPORT_SYMBOL(clk_get); |
| 113 | |
| 114 | static void __clk_disable(struct clk *clk) |
| 115 | { |
| 116 | if (clk == NULL || IS_ERR(clk)) |
| 117 | return; |
| 118 | |
| 119 | __clk_disable(clk->parent); |
| 120 | __clk_disable(clk->secondary); |
| 121 | |
| 122 | if (!(--clk->usecount) && clk->disable) |
| 123 | clk->disable(clk); |
| 124 | } |
| 125 | |
| 126 | static int __clk_enable(struct clk *clk) |
| 127 | { |
| 128 | if (clk == NULL || IS_ERR(clk)) |
| 129 | return -EINVAL; |
| 130 | |
| 131 | __clk_enable(clk->parent); |
| 132 | __clk_enable(clk->secondary); |
| 133 | |
| 134 | if (clk->usecount++ == 0 && clk->enable) |
| 135 | clk->enable(clk); |
| 136 | |
| 137 | return 0; |
| 138 | } |
| 139 | |
| 140 | /* This function increments the reference count on the clock and enables the |
| 141 | * clock if not already enabled. The parent clock tree is recursively enabled |
| 142 | */ |
| 143 | int clk_enable(struct clk *clk) |
| 144 | { |
| 145 | int ret = 0; |
| 146 | |
| 147 | if (clk == NULL || IS_ERR(clk)) |
| 148 | return -EINVAL; |
| 149 | |
| 150 | mutex_lock(&clocks_mutex); |
| 151 | ret = __clk_enable(clk); |
| 152 | mutex_unlock(&clocks_mutex); |
| 153 | |
| 154 | return ret; |
| 155 | } |
| 156 | EXPORT_SYMBOL(clk_enable); |
| 157 | |
| 158 | /* This function decrements the reference count on the clock and disables |
| 159 | * the clock when reference count is 0. The parent clock tree is |
| 160 | * recursively disabled |
| 161 | */ |
| 162 | void clk_disable(struct clk *clk) |
| 163 | { |
| 164 | if (clk == NULL || IS_ERR(clk)) |
| 165 | return; |
| 166 | |
| 167 | mutex_lock(&clocks_mutex); |
| 168 | __clk_disable(clk); |
| 169 | mutex_unlock(&clocks_mutex); |
| 170 | } |
| 171 | EXPORT_SYMBOL(clk_disable); |
| 172 | |
| 173 | /* Retrieve the *current* clock rate. If the clock itself |
| 174 | * does not provide a special calculation routine, ask |
| 175 | * its parent and so on, until one is able to return |
| 176 | * a valid clock rate |
| 177 | */ |
| 178 | unsigned long clk_get_rate(struct clk *clk) |
| 179 | { |
| 180 | if (clk == NULL || IS_ERR(clk)) |
| 181 | return 0UL; |
| 182 | |
| 183 | if (clk->get_rate) |
| 184 | return clk->get_rate(clk); |
| 185 | |
| 186 | return clk_get_rate(clk->parent); |
| 187 | } |
| 188 | EXPORT_SYMBOL(clk_get_rate); |
| 189 | |
| 190 | /* Decrement the clock's module reference count */ |
| 191 | void clk_put(struct clk *clk) |
| 192 | { |
| 193 | if (clk && !IS_ERR(clk)) |
| 194 | module_put(clk->owner); |
| 195 | } |
| 196 | EXPORT_SYMBOL(clk_put); |
| 197 | |
| 198 | /* Round the requested clock rate to the nearest supported |
| 199 | * rate that is less than or equal to the requested rate. |
| 200 | * This is dependent on the clock's current parent. |
| 201 | */ |
| 202 | long clk_round_rate(struct clk *clk, unsigned long rate) |
| 203 | { |
| 204 | if (clk == NULL || IS_ERR(clk) || !clk->round_rate) |
| 205 | return 0; |
| 206 | |
| 207 | return clk->round_rate(clk, rate); |
| 208 | } |
| 209 | EXPORT_SYMBOL(clk_round_rate); |
| 210 | |
| 211 | /* Set the clock to the requested clock rate. The rate must |
| 212 | * match a supported rate exactly based on what clk_round_rate returns |
| 213 | */ |
| 214 | int clk_set_rate(struct clk *clk, unsigned long rate) |
| 215 | { |
| 216 | int ret = -EINVAL; |
| 217 | |
| 218 | if (clk == NULL || IS_ERR(clk) || clk->set_rate == NULL || rate == 0) |
| 219 | return ret; |
| 220 | |
| 221 | mutex_lock(&clocks_mutex); |
| 222 | ret = clk->set_rate(clk, rate); |
| 223 | mutex_unlock(&clocks_mutex); |
| 224 | |
| 225 | return ret; |
| 226 | } |
| 227 | EXPORT_SYMBOL(clk_set_rate); |
| 228 | |
| 229 | /* Set the clock's parent to another clock source */ |
| 230 | int clk_set_parent(struct clk *clk, struct clk *parent) |
| 231 | { |
| 232 | int ret = -EINVAL; |
| 233 | |
| 234 | if (clk == NULL || IS_ERR(clk) || parent == NULL || |
| 235 | IS_ERR(parent) || clk->set_parent == NULL) |
| 236 | return ret; |
| 237 | |
| 238 | mutex_lock(&clocks_mutex); |
| 239 | ret = clk->set_parent(clk, parent); |
| 240 | if (ret == 0) |
| 241 | clk->parent = parent; |
| 242 | mutex_unlock(&clocks_mutex); |
| 243 | |
| 244 | return ret; |
| 245 | } |
| 246 | EXPORT_SYMBOL(clk_set_parent); |
| 247 | |
| 248 | /* Retrieve the clock's parent clock source */ |
| 249 | struct clk *clk_get_parent(struct clk *clk) |
| 250 | { |
| 251 | struct clk *ret = NULL; |
| 252 | |
| 253 | if (clk == NULL || IS_ERR(clk)) |
| 254 | return ret; |
| 255 | |
| 256 | return clk->parent; |
| 257 | } |
| 258 | EXPORT_SYMBOL(clk_get_parent); |
| 259 | |
| 260 | /* |
| 261 | * Add a new clock to the clock tree. |
| 262 | */ |
| 263 | int clk_register(struct clk *clk) |
| 264 | { |
| 265 | if (clk == NULL || IS_ERR(clk)) |
| 266 | return -EINVAL; |
| 267 | |
| 268 | mutex_lock(&clocks_mutex); |
| 269 | list_add(&clk->node, &clocks); |
| 270 | mutex_unlock(&clocks_mutex); |
| 271 | |
| 272 | return 0; |
| 273 | } |
| 274 | EXPORT_SYMBOL(clk_register); |
| 275 | |
| 276 | /* Remove a clock from the clock tree */ |
| 277 | void clk_unregister(struct clk *clk) |
| 278 | { |
| 279 | if (clk == NULL || IS_ERR(clk)) |
| 280 | return; |
| 281 | |
| 282 | mutex_lock(&clocks_mutex); |
| 283 | list_del(&clk->node); |
| 284 | mutex_unlock(&clocks_mutex); |
| 285 | } |
| 286 | EXPORT_SYMBOL(clk_unregister); |
| 287 | |
| 288 | #ifdef CONFIG_PROC_FS |
| 289 | static int mxc_clock_read_proc(char *page, char **start, off_t off, |
| 290 | int count, int *eof, void *data) |
| 291 | { |
| 292 | struct clk *clkp; |
| 293 | char *p = page; |
| 294 | int len; |
| 295 | |
| 296 | list_for_each_entry(clkp, &clocks, node) { |
| 297 | p += sprintf(p, "%s-%d:\t\t%lu, %d", clkp->name, clkp->id, |
| 298 | clk_get_rate(clkp), clkp->usecount); |
| 299 | if (clkp->parent) |
| 300 | p += sprintf(p, ", %s-%d\n", clkp->parent->name, |
| 301 | clkp->parent->id); |
| 302 | else |
| 303 | p += sprintf(p, "\n"); |
| 304 | } |
| 305 | |
| 306 | len = (p - page) - off; |
| 307 | if (len < 0) |
| 308 | len = 0; |
| 309 | |
| 310 | *eof = (len <= count) ? 1 : 0; |
| 311 | *start = page + off; |
| 312 | |
| 313 | return len; |
| 314 | } |
| 315 | |
| 316 | static int __init mxc_setup_proc_entry(void) |
| 317 | { |
| 318 | struct proc_dir_entry *res; |
| 319 | |
| 320 | res = create_proc_read_entry("cpu/clocks", 0, NULL, |
| 321 | mxc_clock_read_proc, NULL); |
| 322 | if (!res) { |
| 323 | printk(KERN_ERR "Failed to create proc/cpu/clocks\n"); |
| 324 | return -ENOMEM; |
| 325 | } |
| 326 | return 0; |
| 327 | } |
| 328 | |
| 329 | late_initcall(mxc_setup_proc_entry); |
| 330 | #endif |