OMAP clock: add omap_clk_get_by_name() for use by OMAP hwmod core code
[pandora-kernel.git] / 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 <plat/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 int clk_enable(struct clk *clk)
40 {
41         unsigned long flags;
42         int ret = 0;
43
44         if (clk == NULL || IS_ERR(clk))
45                 return -EINVAL;
46
47         spin_lock_irqsave(&clockfw_lock, flags);
48         if (arch_clock->clk_enable)
49                 ret = arch_clock->clk_enable(clk);
50         spin_unlock_irqrestore(&clockfw_lock, flags);
51
52         return ret;
53 }
54 EXPORT_SYMBOL(clk_enable);
55
56 void clk_disable(struct clk *clk)
57 {
58         unsigned long flags;
59
60         if (clk == NULL || IS_ERR(clk))
61                 return;
62
63         spin_lock_irqsave(&clockfw_lock, flags);
64         if (clk->usecount == 0) {
65                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
66                        clk->name);
67                 WARN_ON(1);
68                 goto out;
69         }
70
71         if (arch_clock->clk_disable)
72                 arch_clock->clk_disable(clk);
73
74 out:
75         spin_unlock_irqrestore(&clockfw_lock, flags);
76 }
77 EXPORT_SYMBOL(clk_disable);
78
79 unsigned long clk_get_rate(struct clk *clk)
80 {
81         unsigned long flags;
82         unsigned long ret = 0;
83
84         if (clk == NULL || IS_ERR(clk))
85                 return 0;
86
87         spin_lock_irqsave(&clockfw_lock, flags);
88         ret = clk->rate;
89         spin_unlock_irqrestore(&clockfw_lock, flags);
90
91         return ret;
92 }
93 EXPORT_SYMBOL(clk_get_rate);
94
95 /*-------------------------------------------------------------------------
96  * Optional clock functions defined in include/linux/clk.h
97  *-------------------------------------------------------------------------*/
98
99 long clk_round_rate(struct clk *clk, unsigned long rate)
100 {
101         unsigned long flags;
102         long ret = 0;
103
104         if (clk == NULL || IS_ERR(clk))
105                 return ret;
106
107         spin_lock_irqsave(&clockfw_lock, flags);
108         if (arch_clock->clk_round_rate)
109                 ret = arch_clock->clk_round_rate(clk, rate);
110         spin_unlock_irqrestore(&clockfw_lock, flags);
111
112         return ret;
113 }
114 EXPORT_SYMBOL(clk_round_rate);
115
116 int clk_set_rate(struct clk *clk, unsigned long rate)
117 {
118         unsigned long flags;
119         int ret = -EINVAL;
120
121         if (clk == NULL || IS_ERR(clk))
122                 return ret;
123
124         spin_lock_irqsave(&clockfw_lock, flags);
125         if (arch_clock->clk_set_rate)
126                 ret = arch_clock->clk_set_rate(clk, rate);
127         if (ret == 0) {
128                 if (clk->recalc)
129                         clk->rate = clk->recalc(clk);
130                 propagate_rate(clk);
131         }
132         spin_unlock_irqrestore(&clockfw_lock, flags);
133
134         return ret;
135 }
136 EXPORT_SYMBOL(clk_set_rate);
137
138 int clk_set_parent(struct clk *clk, struct clk *parent)
139 {
140         unsigned long flags;
141         int ret = -EINVAL;
142
143         if (cpu_is_omap44xx())
144         /* OMAP4 clk framework not supported yet */
145                 return 0;
146         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
147                 return ret;
148
149         spin_lock_irqsave(&clockfw_lock, flags);
150         if (clk->usecount == 0) {
151                 if (arch_clock->clk_set_parent)
152                         ret = arch_clock->clk_set_parent(clk, parent);
153                 if (ret == 0) {
154                         if (clk->recalc)
155                                 clk->rate = clk->recalc(clk);
156                         propagate_rate(clk);
157                 }
158         } else
159                 ret = -EBUSY;
160         spin_unlock_irqrestore(&clockfw_lock, flags);
161
162         return ret;
163 }
164 EXPORT_SYMBOL(clk_set_parent);
165
166 struct clk *clk_get_parent(struct clk *clk)
167 {
168         return clk->parent;
169 }
170 EXPORT_SYMBOL(clk_get_parent);
171
172 /*-------------------------------------------------------------------------
173  * OMAP specific clock functions shared between omap1 and omap2
174  *-------------------------------------------------------------------------*/
175
176 int __initdata mpurate;
177
178 /*
179  * By default we use the rate set by the bootloader.
180  * You can override this with mpurate= cmdline option.
181  */
182 static int __init omap_clk_setup(char *str)
183 {
184         get_option(&str, &mpurate);
185
186         if (!mpurate)
187                 return 1;
188
189         if (mpurate < 1000)
190                 mpurate *= 1000000;
191
192         return 1;
193 }
194 __setup("mpurate=", omap_clk_setup);
195
196 /* Used for clocks that always have same value as the parent clock */
197 unsigned long followparent_recalc(struct clk *clk)
198 {
199         return clk->parent->rate;
200 }
201
202 /*
203  * Used for clocks that have the same value as the parent clock,
204  * divided by some factor
205  */
206 unsigned long omap_fixed_divisor_recalc(struct clk *clk)
207 {
208         WARN_ON(!clk->fixed_div);
209
210         return clk->parent->rate / clk->fixed_div;
211 }
212
213 void clk_reparent(struct clk *child, struct clk *parent)
214 {
215         list_del_init(&child->sibling);
216         if (parent)
217                 list_add(&child->sibling, &parent->children);
218         child->parent = parent;
219
220         /* now do the debugfs renaming to reattach the child
221            to the proper parent */
222 }
223
224 /* Propagate rate to children */
225 void propagate_rate(struct clk * tclk)
226 {
227         struct clk *clkp;
228
229         list_for_each_entry(clkp, &tclk->children, sibling) {
230                 if (clkp->recalc)
231                         clkp->rate = clkp->recalc(clkp);
232                 propagate_rate(clkp);
233         }
234 }
235
236 static LIST_HEAD(root_clks);
237
238 /**
239  * recalculate_root_clocks - recalculate and propagate all root clocks
240  *
241  * Recalculates all root clocks (clocks with no parent), which if the
242  * clock's .recalc is set correctly, should also propagate their rates.
243  * Called at init.
244  */
245 void recalculate_root_clocks(void)
246 {
247         struct clk *clkp;
248
249         list_for_each_entry(clkp, &root_clks, sibling) {
250                 if (clkp->recalc)
251                         clkp->rate = clkp->recalc(clkp);
252                 propagate_rate(clkp);
253         }
254 }
255
256 /**
257  * clk_preinit - initialize any fields in the struct clk before clk init
258  * @clk: struct clk * to initialize
259  *
260  * Initialize any struct clk fields needed before normal clk initialization
261  * can run.  No return value.
262  */
263 void clk_preinit(struct clk *clk)
264 {
265         INIT_LIST_HEAD(&clk->children);
266 }
267
268 int clk_register(struct clk *clk)
269 {
270         if (clk == NULL || IS_ERR(clk))
271                 return -EINVAL;
272
273         /*
274          * trap out already registered clocks
275          */
276         if (clk->node.next || clk->node.prev)
277                 return 0;
278
279         mutex_lock(&clocks_mutex);
280         if (clk->parent)
281                 list_add(&clk->sibling, &clk->parent->children);
282         else
283                 list_add(&clk->sibling, &root_clks);
284
285         list_add(&clk->node, &clocks);
286         if (clk->init)
287                 clk->init(clk);
288         mutex_unlock(&clocks_mutex);
289
290         return 0;
291 }
292 EXPORT_SYMBOL(clk_register);
293
294 void clk_unregister(struct clk *clk)
295 {
296         if (clk == NULL || IS_ERR(clk))
297                 return;
298
299         mutex_lock(&clocks_mutex);
300         list_del(&clk->sibling);
301         list_del(&clk->node);
302         mutex_unlock(&clocks_mutex);
303 }
304 EXPORT_SYMBOL(clk_unregister);
305
306 void clk_enable_init_clocks(void)
307 {
308         struct clk *clkp;
309
310         list_for_each_entry(clkp, &clocks, node) {
311                 if (clkp->flags & ENABLE_ON_INIT)
312                         clk_enable(clkp);
313         }
314 }
315
316 /**
317  * omap_clk_get_by_name - locate OMAP struct clk by its name
318  * @name: name of the struct clk to locate
319  *
320  * Locate an OMAP struct clk by its name.  Assumes that struct clk
321  * names are unique.  Returns NULL if not found or a pointer to the
322  * struct clk if found.
323  */
324 struct clk *omap_clk_get_by_name(const char *name)
325 {
326         struct clk *c;
327         struct clk *ret = NULL;
328
329         mutex_lock(&clocks_mutex);
330
331         list_for_each_entry(c, &clocks, node) {
332                 if (!strcmp(c->name, name)) {
333                         ret = c;
334                         break;
335                 }
336         }
337
338         mutex_unlock(&clocks_mutex);
339
340         return ret;
341 }
342
343 /*
344  * Low level helpers
345  */
346 static int clkll_enable_null(struct clk *clk)
347 {
348         return 0;
349 }
350
351 static void clkll_disable_null(struct clk *clk)
352 {
353 }
354
355 const struct clkops clkops_null = {
356         .enable         = clkll_enable_null,
357         .disable        = clkll_disable_null,
358 };
359
360 #ifdef CONFIG_CPU_FREQ
361 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
362 {
363         unsigned long flags;
364
365         spin_lock_irqsave(&clockfw_lock, flags);
366         if (arch_clock->clk_init_cpufreq_table)
367                 arch_clock->clk_init_cpufreq_table(table);
368         spin_unlock_irqrestore(&clockfw_lock, flags);
369 }
370
371 void clk_exit_cpufreq_table(struct cpufreq_frequency_table **table)
372 {
373         unsigned long flags;
374
375         spin_lock_irqsave(&clockfw_lock, flags);
376         if (arch_clock->clk_exit_cpufreq_table)
377                 arch_clock->clk_exit_cpufreq_table(table);
378         spin_unlock_irqrestore(&clockfw_lock, flags);
379 }
380 #endif
381
382 /*-------------------------------------------------------------------------*/
383
384 #ifdef CONFIG_OMAP_RESET_CLOCKS
385 /*
386  * Disable any unused clocks left on by the bootloader
387  */
388 static int __init clk_disable_unused(void)
389 {
390         struct clk *ck;
391         unsigned long flags;
392
393         list_for_each_entry(ck, &clocks, node) {
394                 if (ck->ops == &clkops_null)
395                         continue;
396
397                 if (ck->usecount > 0 || ck->enable_reg == 0)
398                         continue;
399
400                 spin_lock_irqsave(&clockfw_lock, flags);
401                 if (arch_clock->clk_disable_unused)
402                         arch_clock->clk_disable_unused(ck);
403                 spin_unlock_irqrestore(&clockfw_lock, flags);
404         }
405
406         return 0;
407 }
408 late_initcall(clk_disable_unused);
409 #endif
410
411 int __init clk_init(struct clk_functions * custom_clocks)
412 {
413         if (!custom_clocks) {
414                 printk(KERN_ERR "No custom clock functions registered\n");
415                 BUG();
416         }
417
418         arch_clock = custom_clocks;
419
420         return 0;
421 }
422
423 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
424 /*
425  *      debugfs support to trace clock tree hierarchy and attributes
426  */
427 static struct dentry *clk_debugfs_root;
428
429 static int clk_debugfs_register_one(struct clk *c)
430 {
431         int err;
432         struct dentry *d, *child, *child_tmp;
433         struct clk *pa = c->parent;
434         char s[255];
435         char *p = s;
436
437         p += sprintf(p, "%s", c->name);
438         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
439         if (!d)
440                 return -ENOMEM;
441         c->dent = d;
442
443         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
444         if (!d) {
445                 err = -ENOMEM;
446                 goto err_out;
447         }
448         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
449         if (!d) {
450                 err = -ENOMEM;
451                 goto err_out;
452         }
453         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
454         if (!d) {
455                 err = -ENOMEM;
456                 goto err_out;
457         }
458         return 0;
459
460 err_out:
461         d = c->dent;
462         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
463                 debugfs_remove(child);
464         debugfs_remove(c->dent);
465         return err;
466 }
467
468 static int clk_debugfs_register(struct clk *c)
469 {
470         int err;
471         struct clk *pa = c->parent;
472
473         if (pa && !pa->dent) {
474                 err = clk_debugfs_register(pa);
475                 if (err)
476                         return err;
477         }
478
479         if (!c->dent) {
480                 err = clk_debugfs_register_one(c);
481                 if (err)
482                         return err;
483         }
484         return 0;
485 }
486
487 static int __init clk_debugfs_init(void)
488 {
489         struct clk *c;
490         struct dentry *d;
491         int err;
492
493         d = debugfs_create_dir("clock", NULL);
494         if (!d)
495                 return -ENOMEM;
496         clk_debugfs_root = d;
497
498         list_for_each_entry(c, &clocks, node) {
499                 err = clk_debugfs_register(c);
500                 if (err)
501                         goto err_out;
502         }
503         return 0;
504 err_out:
505         debugfs_remove_recursive(clk_debugfs_root);
506         return err;
507 }
508 late_initcall(clk_debugfs_init);
509
510 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */