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c0db2ea4 JB |
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 | #include <linux/version.h> | |
41 | ||
42 | #include <asm/arch/clock.h> | |
43 | ||
44 | static LIST_HEAD(clocks); | |
45 | static DEFINE_MUTEX(clocks_mutex); | |
46 | ||
47 | /*------------------------------------------------------------------------- | |
48 | * Standard clock functions defined in include/linux/clk.h | |
49 | *-------------------------------------------------------------------------*/ | |
50 | ||
51 | /* | |
52 | * Retrieve a clock by name. | |
53 | * | |
54 | * Note that we first try to use device id on the bus | |
55 | * and clock name. If this fails, we try to use "<name>.<id>". If this fails, | |
56 | * we try to use clock name only. | |
57 | * The reference count to the clock's module owner ref count is incremented. | |
58 | */ | |
59 | struct clk *clk_get(struct device *dev, const char *id) | |
60 | { | |
61 | struct clk *p, *clk = ERR_PTR(-ENOENT); | |
62 | int idno; | |
63 | const char *str; | |
64 | ||
65 | if (id == NULL) | |
66 | return clk; | |
67 | ||
68 | if (dev == NULL || dev->bus != &platform_bus_type) | |
69 | idno = -1; | |
70 | else | |
71 | idno = to_platform_device(dev)->id; | |
72 | ||
73 | mutex_lock(&clocks_mutex); | |
74 | ||
75 | list_for_each_entry(p, &clocks, node) { | |
76 | if (p->id == idno && | |
77 | strcmp(id, p->name) == 0 && try_module_get(p->owner)) { | |
78 | clk = p; | |
79 | goto found; | |
80 | } | |
81 | } | |
82 | ||
83 | str = strrchr(id, '.'); | |
84 | if (str) { | |
85 | int cnt = str - id; | |
86 | str++; | |
87 | idno = simple_strtol(str, NULL, 10); | |
88 | list_for_each_entry(p, &clocks, node) { | |
89 | if (p->id == idno && | |
90 | strlen(p->name) == cnt && | |
91 | strncmp(id, p->name, cnt) == 0 && | |
92 | try_module_get(p->owner)) { | |
93 | clk = p; | |
94 | goto found; | |
95 | } | |
96 | } | |
97 | } | |
98 | ||
99 | list_for_each_entry(p, &clocks, node) { | |
100 | if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) { | |
101 | clk = p; | |
102 | goto found; | |
103 | } | |
104 | } | |
105 | ||
106 | printk(KERN_WARNING "clk: Unable to get requested clock: %s\n", id); | |
107 | ||
108 | found: | |
109 | mutex_unlock(&clocks_mutex); | |
110 | ||
111 | return clk; | |
112 | } | |
113 | EXPORT_SYMBOL(clk_get); | |
114 | ||
115 | static void __clk_disable(struct clk *clk) | |
116 | { | |
117 | if (clk == NULL || IS_ERR(clk)) | |
118 | return; | |
119 | ||
120 | __clk_disable(clk->parent); | |
121 | __clk_disable(clk->secondary); | |
122 | ||
123 | if (!(--clk->usecount) && clk->disable) | |
124 | clk->disable(clk); | |
125 | } | |
126 | ||
127 | static int __clk_enable(struct clk *clk) | |
128 | { | |
129 | if (clk == NULL || IS_ERR(clk)) | |
130 | return -EINVAL; | |
131 | ||
132 | __clk_enable(clk->parent); | |
133 | __clk_enable(clk->secondary); | |
134 | ||
135 | if (clk->usecount++ == 0 && clk->enable) | |
136 | clk->enable(clk); | |
137 | ||
138 | return 0; | |
139 | } | |
140 | ||
141 | /* This function increments the reference count on the clock and enables the | |
142 | * clock if not already enabled. The parent clock tree is recursively enabled | |
143 | */ | |
144 | int clk_enable(struct clk *clk) | |
145 | { | |
146 | int ret = 0; | |
147 | ||
148 | if (clk == NULL || IS_ERR(clk)) | |
149 | return -EINVAL; | |
150 | ||
151 | mutex_lock(&clocks_mutex); | |
152 | ret = __clk_enable(clk); | |
153 | mutex_unlock(&clocks_mutex); | |
154 | ||
155 | return ret; | |
156 | } | |
157 | EXPORT_SYMBOL(clk_enable); | |
158 | ||
159 | /* This function decrements the reference count on the clock and disables | |
160 | * the clock when reference count is 0. The parent clock tree is | |
161 | * recursively disabled | |
162 | */ | |
163 | void clk_disable(struct clk *clk) | |
164 | { | |
165 | if (clk == NULL || IS_ERR(clk)) | |
166 | return; | |
167 | ||
168 | mutex_lock(&clocks_mutex); | |
169 | __clk_disable(clk); | |
170 | mutex_unlock(&clocks_mutex); | |
171 | } | |
172 | EXPORT_SYMBOL(clk_disable); | |
173 | ||
174 | /* Retrieve the *current* clock rate. If the clock itself | |
175 | * does not provide a special calculation routine, ask | |
176 | * its parent and so on, until one is able to return | |
177 | * a valid clock rate | |
178 | */ | |
179 | unsigned long clk_get_rate(struct clk *clk) | |
180 | { | |
181 | if (clk == NULL || IS_ERR(clk)) | |
182 | return 0UL; | |
183 | ||
184 | if (clk->get_rate) | |
185 | return clk->get_rate(clk); | |
186 | ||
187 | return clk_get_rate(clk->parent); | |
188 | } | |
189 | EXPORT_SYMBOL(clk_get_rate); | |
190 | ||
191 | /* Decrement the clock's module reference count */ | |
192 | void clk_put(struct clk *clk) | |
193 | { | |
194 | if (clk && !IS_ERR(clk)) | |
195 | module_put(clk->owner); | |
196 | } | |
197 | EXPORT_SYMBOL(clk_put); | |
198 | ||
199 | /* Round the requested clock rate to the nearest supported | |
200 | * rate that is less than or equal to the requested rate. | |
201 | * This is dependent on the clock's current parent. | |
202 | */ | |
203 | long clk_round_rate(struct clk *clk, unsigned long rate) | |
204 | { | |
205 | if (clk == NULL || IS_ERR(clk) || !clk->round_rate) | |
206 | return 0; | |
207 | ||
208 | return clk->round_rate(clk, rate); | |
209 | } | |
210 | EXPORT_SYMBOL(clk_round_rate); | |
211 | ||
212 | /* Set the clock to the requested clock rate. The rate must | |
213 | * match a supported rate exactly based on what clk_round_rate returns | |
214 | */ | |
215 | int clk_set_rate(struct clk *clk, unsigned long rate) | |
216 | { | |
217 | int ret = -EINVAL; | |
218 | ||
219 | if (clk == NULL || IS_ERR(clk) || clk->set_rate == NULL || rate == 0) | |
220 | return ret; | |
221 | ||
222 | mutex_lock(&clocks_mutex); | |
223 | ret = clk->set_rate(clk, rate); | |
224 | mutex_unlock(&clocks_mutex); | |
225 | ||
226 | return ret; | |
227 | } | |
228 | EXPORT_SYMBOL(clk_set_rate); | |
229 | ||
230 | /* Set the clock's parent to another clock source */ | |
231 | int clk_set_parent(struct clk *clk, struct clk *parent) | |
232 | { | |
233 | int ret = -EINVAL; | |
234 | ||
235 | if (clk == NULL || IS_ERR(clk) || parent == NULL || | |
236 | IS_ERR(parent) || clk->set_parent == NULL) | |
237 | return ret; | |
238 | ||
239 | mutex_lock(&clocks_mutex); | |
240 | ret = clk->set_parent(clk, parent); | |
241 | if (ret == 0) | |
242 | clk->parent = parent; | |
243 | mutex_unlock(&clocks_mutex); | |
244 | ||
245 | return ret; | |
246 | } | |
247 | EXPORT_SYMBOL(clk_set_parent); | |
248 | ||
249 | /* Retrieve the clock's parent clock source */ | |
250 | struct clk *clk_get_parent(struct clk *clk) | |
251 | { | |
252 | struct clk *ret = NULL; | |
253 | ||
254 | if (clk == NULL || IS_ERR(clk)) | |
255 | return ret; | |
256 | ||
257 | return clk->parent; | |
258 | } | |
259 | EXPORT_SYMBOL(clk_get_parent); | |
260 | ||
261 | /* | |
262 | * Add a new clock to the clock tree. | |
263 | */ | |
264 | int clk_register(struct clk *clk) | |
265 | { | |
266 | if (clk == NULL || IS_ERR(clk)) | |
267 | return -EINVAL; | |
268 | ||
269 | mutex_lock(&clocks_mutex); | |
270 | list_add(&clk->node, &clocks); | |
271 | mutex_unlock(&clocks_mutex); | |
272 | ||
273 | return 0; | |
274 | } | |
275 | EXPORT_SYMBOL(clk_register); | |
276 | ||
277 | /* Remove a clock from the clock tree */ | |
278 | void clk_unregister(struct clk *clk) | |
279 | { | |
280 | if (clk == NULL || IS_ERR(clk)) | |
281 | return; | |
282 | ||
283 | mutex_lock(&clocks_mutex); | |
284 | list_del(&clk->node); | |
285 | mutex_unlock(&clocks_mutex); | |
286 | } | |
287 | EXPORT_SYMBOL(clk_unregister); | |
288 | ||
289 | #ifdef CONFIG_PROC_FS | |
290 | static int mxc_clock_read_proc(char *page, char **start, off_t off, | |
291 | int count, int *eof, void *data) | |
292 | { | |
293 | struct clk *clkp; | |
294 | char *p = page; | |
295 | int len; | |
296 | ||
297 | list_for_each_entry(clkp, &clocks, node) { | |
298 | p += sprintf(p, "%s-%d:\t\t%lu, %d", clkp->name, clkp->id, | |
299 | clk_get_rate(clkp), clkp->usecount); | |
300 | if (clkp->parent) | |
301 | p += sprintf(p, ", %s-%d\n", clkp->parent->name, | |
302 | clkp->parent->id); | |
303 | else | |
304 | p += sprintf(p, "\n"); | |
305 | } | |
306 | ||
307 | len = (p - page) - off; | |
308 | if (len < 0) | |
309 | len = 0; | |
310 | ||
311 | *eof = (len <= count) ? 1 : 0; | |
312 | *start = page + off; | |
313 | ||
314 | return len; | |
315 | } | |
316 | ||
317 | static int __init mxc_setup_proc_entry(void) | |
318 | { | |
319 | struct proc_dir_entry *res; | |
320 | ||
321 | res = create_proc_read_entry("cpu/clocks", 0, NULL, | |
322 | mxc_clock_read_proc, NULL); | |
323 | if (!res) { | |
324 | printk(KERN_ERR "Failed to create proc/cpu/clocks\n"); | |
325 | return -ENOMEM; | |
326 | } | |
327 | return 0; | |
328 | } | |
329 | ||
330 | late_initcall(mxc_setup_proc_entry); | |
331 | #endif |