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-rw-r--r--drivers/media/v4l2-core/Makefile2
-rw-r--r--drivers/media/v4l2-core/v4l2-clk.c242
-rw-r--r--include/media/v4l2-clk.h54
3 files changed, 297 insertions, 1 deletions
diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile
index aa50c46314b7..628c6307e978 100644
--- a/drivers/media/v4l2-core/Makefile
+++ b/drivers/media/v4l2-core/Makefile
@@ -5,7 +5,7 @@
5tuner-objs := tuner-core.o 5tuner-objs := tuner-core.o
6 6
7videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \ 7videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
8 v4l2-event.o v4l2-ctrls.o v4l2-subdev.o 8 v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o
9ifeq ($(CONFIG_COMPAT),y) 9ifeq ($(CONFIG_COMPAT),y)
10 videodev-objs += v4l2-compat-ioctl32.o 10 videodev-objs += v4l2-compat-ioctl32.o
11endif 11endif
diff --git a/drivers/media/v4l2-core/v4l2-clk.c b/drivers/media/v4l2-core/v4l2-clk.c
new file mode 100644
index 000000000000..b67de8642b5a
--- /dev/null
+++ b/drivers/media/v4l2-core/v4l2-clk.c
@@ -0,0 +1,242 @@
1/*
2 * V4L2 clock service
3 *
4 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/atomic.h>
12#include <linux/device.h>
13#include <linux/errno.h>
14#include <linux/list.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/slab.h>
18#include <linux/string.h>
19
20#include <media/v4l2-clk.h>
21#include <media/v4l2-subdev.h>
22
23static DEFINE_MUTEX(clk_lock);
24static LIST_HEAD(clk_list);
25
26static struct v4l2_clk *v4l2_clk_find(const char *dev_id, const char *id)
27{
28 struct v4l2_clk *clk;
29
30 list_for_each_entry(clk, &clk_list, list) {
31 if (strcmp(dev_id, clk->dev_id))
32 continue;
33
34 if (!id || !clk->id || !strcmp(clk->id, id))
35 return clk;
36 }
37
38 return ERR_PTR(-ENODEV);
39}
40
41struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id)
42{
43 struct v4l2_clk *clk;
44
45 mutex_lock(&clk_lock);
46 clk = v4l2_clk_find(dev_name(dev), id);
47
48 if (!IS_ERR(clk))
49 atomic_inc(&clk->use_count);
50 mutex_unlock(&clk_lock);
51
52 return clk;
53}
54EXPORT_SYMBOL(v4l2_clk_get);
55
56void v4l2_clk_put(struct v4l2_clk *clk)
57{
58 struct v4l2_clk *tmp;
59
60 if (IS_ERR(clk))
61 return;
62
63 mutex_lock(&clk_lock);
64
65 list_for_each_entry(tmp, &clk_list, list)
66 if (tmp == clk)
67 atomic_dec(&clk->use_count);
68
69 mutex_unlock(&clk_lock);
70}
71EXPORT_SYMBOL(v4l2_clk_put);
72
73static int v4l2_clk_lock_driver(struct v4l2_clk *clk)
74{
75 struct v4l2_clk *tmp;
76 int ret = -ENODEV;
77
78 mutex_lock(&clk_lock);
79
80 list_for_each_entry(tmp, &clk_list, list)
81 if (tmp == clk) {
82 ret = !try_module_get(clk->ops->owner);
83 if (ret)
84 ret = -EFAULT;
85 break;
86 }
87
88 mutex_unlock(&clk_lock);
89
90 return ret;
91}
92
93static void v4l2_clk_unlock_driver(struct v4l2_clk *clk)
94{
95 module_put(clk->ops->owner);
96}
97
98int v4l2_clk_enable(struct v4l2_clk *clk)
99{
100 int ret = v4l2_clk_lock_driver(clk);
101
102 if (ret < 0)
103 return ret;
104
105 mutex_lock(&clk->lock);
106
107 if (++clk->enable == 1 && clk->ops->enable) {
108 ret = clk->ops->enable(clk);
109 if (ret < 0)
110 clk->enable--;
111 }
112
113 mutex_unlock(&clk->lock);
114
115 return ret;
116}
117EXPORT_SYMBOL(v4l2_clk_enable);
118
119/*
120 * You might Oops if you try to disabled a disabled clock, because then the
121 * driver isn't locked and could have been unloaded by now, so, don't do that
122 */
123void v4l2_clk_disable(struct v4l2_clk *clk)
124{
125 int enable;
126
127 mutex_lock(&clk->lock);
128
129 enable = --clk->enable;
130 if (WARN(enable < 0, "Unbalanced %s() on %s:%s!\n", __func__,
131 clk->dev_id, clk->id))
132 clk->enable++;
133 else if (!enable && clk->ops->disable)
134 clk->ops->disable(clk);
135
136 mutex_unlock(&clk->lock);
137
138 v4l2_clk_unlock_driver(clk);
139}
140EXPORT_SYMBOL(v4l2_clk_disable);
141
142unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk)
143{
144 int ret = v4l2_clk_lock_driver(clk);
145
146 if (ret < 0)
147 return ret;
148
149 mutex_lock(&clk->lock);
150 if (!clk->ops->get_rate)
151 ret = -ENOSYS;
152 else
153 ret = clk->ops->get_rate(clk);
154 mutex_unlock(&clk->lock);
155
156 v4l2_clk_unlock_driver(clk);
157
158 return ret;
159}
160EXPORT_SYMBOL(v4l2_clk_get_rate);
161
162int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate)
163{
164 int ret = v4l2_clk_lock_driver(clk);
165
166 if (ret < 0)
167 return ret;
168
169 mutex_lock(&clk->lock);
170 if (!clk->ops->set_rate)
171 ret = -ENOSYS;
172 else
173 ret = clk->ops->set_rate(clk, rate);
174 mutex_unlock(&clk->lock);
175
176 v4l2_clk_unlock_driver(clk);
177
178 return ret;
179}
180EXPORT_SYMBOL(v4l2_clk_set_rate);
181
182struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops,
183 const char *dev_id,
184 const char *id, void *priv)
185{
186 struct v4l2_clk *clk;
187 int ret;
188
189 if (!ops || !dev_id)
190 return ERR_PTR(-EINVAL);
191
192 clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL);
193 if (!clk)
194 return ERR_PTR(-ENOMEM);
195
196 clk->id = kstrdup(id, GFP_KERNEL);
197 clk->dev_id = kstrdup(dev_id, GFP_KERNEL);
198 if ((id && !clk->id) || !clk->dev_id) {
199 ret = -ENOMEM;
200 goto ealloc;
201 }
202 clk->ops = ops;
203 clk->priv = priv;
204 atomic_set(&clk->use_count, 0);
205 mutex_init(&clk->lock);
206
207 mutex_lock(&clk_lock);
208 if (!IS_ERR(v4l2_clk_find(dev_id, id))) {
209 mutex_unlock(&clk_lock);
210 ret = -EEXIST;
211 goto eexist;
212 }
213 list_add_tail(&clk->list, &clk_list);
214 mutex_unlock(&clk_lock);
215
216 return clk;
217
218eexist:
219ealloc:
220 kfree(clk->id);
221 kfree(clk->dev_id);
222 kfree(clk);
223 return ERR_PTR(ret);
224}
225EXPORT_SYMBOL(v4l2_clk_register);
226
227void v4l2_clk_unregister(struct v4l2_clk *clk)
228{
229 if (WARN(atomic_read(&clk->use_count),
230 "%s(): Refusing to unregister ref-counted %s:%s clock!\n",
231 __func__, clk->dev_id, clk->id))
232 return;
233
234 mutex_lock(&clk_lock);
235 list_del(&clk->list);
236 mutex_unlock(&clk_lock);
237
238 kfree(clk->id);
239 kfree(clk->dev_id);
240 kfree(clk);
241}
242EXPORT_SYMBOL(v4l2_clk_unregister);
diff --git a/include/media/v4l2-clk.h b/include/media/v4l2-clk.h
new file mode 100644
index 000000000000..0503a90b48bb
--- /dev/null
+++ b/include/media/v4l2-clk.h
@@ -0,0 +1,54 @@
1/*
2 * V4L2 clock service
3 *
4 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * ATTENTION: This is a temporary API and it shall be replaced by the generic
11 * clock API, when the latter becomes widely available.
12 */
13
14#ifndef MEDIA_V4L2_CLK_H
15#define MEDIA_V4L2_CLK_H
16
17#include <linux/atomic.h>
18#include <linux/list.h>
19#include <linux/mutex.h>
20
21struct module;
22struct device;
23
24struct v4l2_clk {
25 struct list_head list;
26 const struct v4l2_clk_ops *ops;
27 const char *dev_id;
28 const char *id;
29 int enable;
30 struct mutex lock; /* Protect the enable count */
31 atomic_t use_count;
32 void *priv;
33};
34
35struct v4l2_clk_ops {
36 struct module *owner;
37 int (*enable)(struct v4l2_clk *clk);
38 void (*disable)(struct v4l2_clk *clk);
39 unsigned long (*get_rate)(struct v4l2_clk *clk);
40 int (*set_rate)(struct v4l2_clk *clk, unsigned long);
41};
42
43struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops,
44 const char *dev_name,
45 const char *name, void *priv);
46void v4l2_clk_unregister(struct v4l2_clk *clk);
47struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id);
48void v4l2_clk_put(struct v4l2_clk *clk);
49int v4l2_clk_enable(struct v4l2_clk *clk);
50void v4l2_clk_disable(struct v4l2_clk *clk);
51unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk);
52int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate);
53
54#endif
generated by cgit v1.2.2 (git 2.25.0) at 2025-04-15 17:39:38 -0400