aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/plat-mxc/clock.c
blob: 1aa86fd60d711a2ba7c70200fff77253cf1e1ed0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
/*
 * Based on arch/arm/plat-omap/clock.c
 *
 * Copyright (C) 2004 - 2005 Nokia corporation
 * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
 * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
 * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 */

/* #define DEBUG */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/proc_fs.h>
#include <linux/semaphore.h>
#include <linux/string.h>
#include <linux/version.h>

#include <asm/arch/clock.h>

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);

/*-------------------------------------------------------------------------
 * Standard clock functions defined in include/linux/clk.h
 *-------------------------------------------------------------------------*/

/*
 * Retrieve a clock by name.
 *
 * Note that we first try to use device id on the bus
 * and clock name. If this fails, we try to use "<name>.<id>". If this fails,
 * we try to use clock name only.
 * The reference count to the clock's module owner ref count is incremented.
 */
struct clk *clk_get(struct device *dev, const char *id)
{
	struct clk *p, *clk = ERR_PTR(-ENOENT);
	int idno;
	const char *str;

	if (id == NULL)
		return clk;

	if (dev == NULL || dev->bus != &platform_bus_type)
		idno = -1;
	else
		idno = to_platform_device(dev)->id;

	mutex_lock(&clocks_mutex);

	list_for_each_entry(p, &clocks, node) {
		if (p->id == idno &&
		    strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
			clk = p;
			goto found;
		}
	}

	str = strrchr(id, '.');
	if (str) {
		int cnt = str - id;
		str++;
		idno = simple_strtol(str, NULL, 10);
		list_for_each_entry(p, &clocks, node) {
			if (p->id == idno &&
			    strlen(p->name) == cnt &&
			    strncmp(id, p->name, cnt) == 0 &&
			    try_module_get(p->owner)) {
				clk = p;
				goto found;
			}
		}
	}

	list_for_each_entry(p, &clocks, node) {
		if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
			clk = p;
			goto found;
		}
	}

	printk(KERN_WARNING "clk: Unable to get requested clock: %s\n", id);

found:
	mutex_unlock(&clocks_mutex);

	return clk;
}
EXPORT_SYMBOL(clk_get);

static void __clk_disable(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return;

	__clk_disable(clk->parent);
	__clk_disable(clk->secondary);

	if (!(--clk->usecount) && clk->disable)
		clk->disable(clk);
}

static int __clk_enable(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return -EINVAL;

	__clk_enable(clk->parent);
	__clk_enable(clk->secondary);

	if (clk->usecount++ == 0 && clk->enable)
		clk->enable(clk);

	return 0;
}

/* This function increments the reference count on the clock and enables the
 * clock if not already enabled. The parent clock tree is recursively enabled
 */
int clk_enable(struct clk *clk)
{
	int ret = 0;

	if (clk == NULL || IS_ERR(clk))
		return -EINVAL;

	mutex_lock(&clocks_mutex);
	ret = __clk_enable(clk);
	mutex_unlock(&clocks_mutex);

	return ret;
}
EXPORT_SYMBOL(clk_enable);

/* This function decrements the reference count on the clock and disables
 * the clock when reference count is 0. The parent clock tree is
 * recursively disabled
 */
void clk_disable(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return;

	mutex_lock(&clocks_mutex);
	__clk_disable(clk);
	mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_disable);

/* Retrieve the *current* clock rate. If the clock itself
 * does not provide a special calculation routine, ask
 * its parent and so on, until one is able to return
 * a valid clock rate
 */
unsigned long clk_get_rate(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return 0UL;

	if (clk->get_rate)
		return clk->get_rate(clk);

	return clk_get_rate(clk->parent);
}
EXPORT_SYMBOL(clk_get_rate);

/* Decrement the clock's module reference count */
void clk_put(struct clk *clk)
{
	if (clk && !IS_ERR(clk))
		module_put(clk->owner);
}
EXPORT_SYMBOL(clk_put);

/* Round the requested clock rate to the nearest supported
 * rate that is less than or equal to the requested rate.
 * This is dependent on the clock's current parent.
 */
long clk_round_rate(struct clk *clk, unsigned long rate)
{
	if (clk == NULL || IS_ERR(clk) || !clk->round_rate)
		return 0;

	return clk->round_rate(clk, rate);
}
EXPORT_SYMBOL(clk_round_rate);

/* Set the clock to the requested clock rate. The rate must
 * match a supported rate exactly based on what clk_round_rate returns
 */
int clk_set_rate(struct clk *clk, unsigned long rate)
{
	int ret = -EINVAL;

	if (clk == NULL || IS_ERR(clk) || clk->set_rate == NULL || rate == 0)
		return ret;

	mutex_lock(&clocks_mutex);
	ret = clk->set_rate(clk, rate);
	mutex_unlock(&clocks_mutex);

	return ret;
}
EXPORT_SYMBOL(clk_set_rate);

/* Set the clock's parent to another clock source */
int clk_set_parent(struct clk *clk, struct clk *parent)
{
	int ret = -EINVAL;

	if (clk == NULL || IS_ERR(clk) || parent == NULL ||
	    IS_ERR(parent) || clk->set_parent == NULL)
		return ret;

	mutex_lock(&clocks_mutex);
	ret = clk->set_parent(clk, parent);
	if (ret == 0)
		clk->parent = parent;
	mutex_unlock(&clocks_mutex);

	return ret;
}
EXPORT_SYMBOL(clk_set_parent);

/* Retrieve the clock's parent clock source */
struct clk *clk_get_parent(struct clk *clk)
{
	struct clk *ret = NULL;

	if (clk == NULL || IS_ERR(clk))
		return ret;

	return clk->parent;
}
EXPORT_SYMBOL(clk_get_parent);

/*
 * Add a new clock to the clock tree.
 */
int clk_register(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return -EINVAL;

	mutex_lock(&clocks_mutex);
	list_add(&clk->node, &clocks);
	mutex_unlock(&clocks_mutex);

	return 0;
}
EXPORT_SYMBOL(clk_register);

/* Remove a clock from the clock tree */
void clk_unregister(struct clk *clk)
{
	if (clk == NULL || IS_ERR(clk))
		return;

	mutex_lock(&clocks_mutex);
	list_del(&clk->node);
	mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);

#ifdef CONFIG_PROC_FS
static int mxc_clock_read_proc(char *page, char **start, off_t off,
				int count, int *eof, void *data)
{
	struct clk *clkp;
	char *p = page;
	int len;

	list_for_each_entry(clkp, &clocks, node) {
		p += sprintf(p, "%s-%d:\t\t%lu, %d", clkp->name, clkp->id,
				clk_get_rate(clkp), clkp->usecount);
		if (clkp->parent)
			p += sprintf(p, ", %s-%d\n", clkp->parent->name,
				     clkp->parent->id);
		else
			p += sprintf(p, "\n");
	}

	len = (p - page) - off;
	if (len < 0)
		len = 0;

	*eof = (len <= count) ? 1 : 0;
	*start = page + off;

	return len;
}

static int __init mxc_setup_proc_entry(void)
{
	struct proc_dir_entry *res;

	res = create_proc_read_entry("cpu/clocks", 0, NULL,
				     mxc_clock_read_proc, NULL);
	if (!res) {
		printk(KERN_ERR "Failed to create proc/cpu/clocks\n");
		return -ENOMEM;
	}
	return 0;
}

late_initcall(mxc_setup_proc_entry);
#endif