Commit | Line | Data |
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ff5430de GL |
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 | ||
23 | static DEFINE_MUTEX(clk_lock); | |
24 | static LIST_HEAD(clk_list); | |
25 | ||
26 | static 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 | ||
41 | struct 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 | } | |
54 | EXPORT_SYMBOL(v4l2_clk_get); | |
55 | ||
56 | void 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 | } | |
71 | EXPORT_SYMBOL(v4l2_clk_put); | |
72 | ||
73 | static 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 | ||
93 | static void v4l2_clk_unlock_driver(struct v4l2_clk *clk) | |
94 | { | |
95 | module_put(clk->ops->owner); | |
96 | } | |
97 | ||
98 | int 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 | } | |
117 | EXPORT_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 | */ | |
123 | void 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 | } | |
140 | EXPORT_SYMBOL(v4l2_clk_disable); | |
141 | ||
142 | unsigned 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 | } | |
160 | EXPORT_SYMBOL(v4l2_clk_get_rate); | |
161 | ||
162 | int 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 | } | |
180 | EXPORT_SYMBOL(v4l2_clk_set_rate); | |
181 | ||
182 | struct 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 | ||
218 | eexist: | |
219 | ealloc: | |
220 | kfree(clk->id); | |
221 | kfree(clk->dev_id); | |
222 | kfree(clk); | |
223 | return ERR_PTR(ret); | |
224 | } | |
225 | EXPORT_SYMBOL(v4l2_clk_register); | |
226 | ||
227 | void 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 | } | |
242 | EXPORT_SYMBOL(v4l2_clk_unregister); |