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authorJuergen Beisert <j.beisert@pengutronix.de>2008-07-05 04:02:47 -0400
committerRobert Schwebel <r.schwebel@pengutronix.de>2008-07-05 04:02:47 -0400
commitc0db2ea4e366c94dd3f880928c02534156e3d1b9 (patch)
treee8486fedc9d405b2867c3a474ebc18fad394836c /arch/arm/plat-mxc
parent38a41fdf94c449c165213e4665c3f8a0d30f8aba (diff)
MXC family: Add clock handling
Internal clock path handling for the mxc CPUs. Changed against the original Freescale code (and against clocklib for example): - clock rate is always calculated whenever one ask for the current rate (means struct clk has no more a member called "rate"). So switching the PLL base frequency will propagate immediately to all other clocks that are depending on this frequency. Signed-off-by: Juergen Beisert <j.beisert@pengutronix.de>
Diffstat (limited to 'arch/arm/plat-mxc')
-rw-r--r--arch/arm/plat-mxc/Makefile2
-rw-r--r--arch/arm/plat-mxc/clock.c331
2 files changed, 332 insertions, 1 deletions
diff --git a/arch/arm/plat-mxc/Makefile b/arch/arm/plat-mxc/Makefile
index f96dc0362068..3eb181cb7afb 100644
--- a/arch/arm/plat-mxc/Makefile
+++ b/arch/arm/plat-mxc/Makefile
@@ -3,4 +3,4 @@
3# 3#
4 4
5# Common support 5# Common support
6obj-y := irq.o 6obj-y := irq.o clock.o
diff --git a/arch/arm/plat-mxc/clock.c b/arch/arm/plat-mxc/clock.c
new file mode 100644
index 000000000000..1aa86fd60d71
--- /dev/null
+++ b/arch/arm/plat-mxc/clock.c
@@ -0,0 +1,331 @@
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
44static LIST_HEAD(clocks);
45static 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 */
59struct 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
108found:
109 mutex_unlock(&clocks_mutex);
110
111 return clk;
112}
113EXPORT_SYMBOL(clk_get);
114
115static 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
127static 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 */
144int 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}
157EXPORT_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 */
163void 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}
172EXPORT_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 */
179unsigned 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}
189EXPORT_SYMBOL(clk_get_rate);
190
191/* Decrement the clock's module reference count */
192void clk_put(struct clk *clk)
193{
194 if (clk && !IS_ERR(clk))
195 module_put(clk->owner);
196}
197EXPORT_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 */
203long 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}
210EXPORT_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 */
215int 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}
228EXPORT_SYMBOL(clk_set_rate);
229
230/* Set the clock's parent to another clock source */
231int 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}
247EXPORT_SYMBOL(clk_set_parent);
248
249/* Retrieve the clock's parent clock source */
250struct 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}
259EXPORT_SYMBOL(clk_get_parent);
260
261/*
262 * Add a new clock to the clock tree.
263 */
264int 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}
275EXPORT_SYMBOL(clk_register);
276
277/* Remove a clock from the clock tree */
278void 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}
287EXPORT_SYMBOL(clk_unregister);
288
289#ifdef CONFIG_PROC_FS
290static 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
317static 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
330late_initcall(mxc_setup_proc_entry);
331#endif