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Juergen Beisertc0db2ea2008-07-05 10:02:47 +02001/*
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 Beisertc0db2ea2008-07-05 10:02:47 +020040
Russell Kinga09e64f2008-08-05 16:14:15 +010041#include <mach/clock.h>
Juergen Beisertc0db2ea2008-07-05 10:02:47 +020042
43static LIST_HEAD(clocks);
44static DEFINE_MUTEX(clocks_mutex);
45
46/*-------------------------------------------------------------------------
47 * Standard clock functions defined in include/linux/clk.h
48 *-------------------------------------------------------------------------*/
49
50/*
Sascha Hauerd1755e32009-02-16 14:27:06 +010051 * 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/*
Juergen Beisertc0db2ea2008-07-05 10:02:47 +020056 * 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 */
63struct 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
112found:
113 mutex_unlock(&clocks_mutex);
114
115 return clk;
116}
117EXPORT_SYMBOL(clk_get);
Sascha Hauerd1755e32009-02-16 14:27:06 +0100118#endif
Juergen Beisertc0db2ea2008-07-05 10:02:47 +0200119
120static 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
132static 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 */
149int 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}
162EXPORT_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 */
168void 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}
177EXPORT_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 */
184unsigned 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}
194EXPORT_SYMBOL(clk_get_rate);
195
Sascha Hauerd1755e32009-02-16 14:27:06 +0100196#ifndef CONFIG_COMMON_CLKDEV
Juergen Beisertc0db2ea2008-07-05 10:02:47 +0200197/* Decrement the clock's module reference count */
198void clk_put(struct clk *clk)
199{
200 if (clk && !IS_ERR(clk))
201 module_put(clk->owner);
202}
203EXPORT_SYMBOL(clk_put);
Sascha Hauerd1755e32009-02-16 14:27:06 +0100204#endif
Juergen Beisertc0db2ea2008-07-05 10:02:47 +0200205
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 */
210long 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}
217EXPORT_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 */
222int 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}
235EXPORT_SYMBOL(clk_set_rate);
236
237/* Set the clock's parent to another clock source */
238int 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}
254EXPORT_SYMBOL(clk_set_parent);
255
256/* Retrieve the clock's parent clock source */
257struct 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}
266EXPORT_SYMBOL(clk_get_parent);
267
Sascha Hauerd1755e32009-02-16 14:27:06 +0100268#ifndef CONFIG_COMMON_CLKDEV
Juergen Beisertc0db2ea2008-07-05 10:02:47 +0200269/*
270 * Add a new clock to the clock tree.
271 */
272int 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}
283EXPORT_SYMBOL(clk_register);
284
285/* Remove a clock from the clock tree */
286void 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}
295EXPORT_SYMBOL(clk_unregister);
296
297#ifdef CONFIG_PROC_FS
298static 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
325static 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
338late_initcall(mxc_setup_proc_entry);
Sascha Hauerd1755e32009-02-16 14:27:06 +0100339#endif /* CONFIG_PROC_FS */
Juergen Beisertc0db2ea2008-07-05 10:02:47 +0200340#endif
Sascha Hauera2865192009-01-26 15:41:16 +0100341
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 */
351unsigned 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}