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> | |
4f528afc | 12 | #include <linux/clk.h> |
ff5430de GL |
13 | #include <linux/device.h> |
14 | #include <linux/errno.h> | |
15 | #include <linux/list.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/mutex.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/string.h> | |
20 | ||
21 | #include <media/v4l2-clk.h> | |
22 | #include <media/v4l2-subdev.h> | |
23 | ||
24 | static DEFINE_MUTEX(clk_lock); | |
25 | static LIST_HEAD(clk_list); | |
26 | ||
a37462b9 | 27 | static struct v4l2_clk *v4l2_clk_find(const char *dev_id) |
ff5430de GL |
28 | { |
29 | struct v4l2_clk *clk; | |
30 | ||
a37462b9 GL |
31 | list_for_each_entry(clk, &clk_list, list) |
32 | if (!strcmp(dev_id, clk->dev_id)) | |
ff5430de | 33 | return clk; |
ff5430de GL |
34 | |
35 | return ERR_PTR(-ENODEV); | |
36 | } | |
37 | ||
38 | struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id) | |
39 | { | |
40 | struct v4l2_clk *clk; | |
4f528afc GL |
41 | struct clk *ccf_clk = clk_get(dev, id); |
42 | ||
43 | if (PTR_ERR(ccf_clk) == -EPROBE_DEFER) | |
44 | return ERR_PTR(-EPROBE_DEFER); | |
45 | ||
46 | if (!IS_ERR_OR_NULL(ccf_clk)) { | |
47 | clk = kzalloc(sizeof(*clk), GFP_KERNEL); | |
48 | if (!clk) { | |
49 | clk_put(ccf_clk); | |
50 | return ERR_PTR(-ENOMEM); | |
51 | } | |
52 | clk->clk = ccf_clk; | |
53 | ||
54 | return clk; | |
55 | } | |
ff5430de GL |
56 | |
57 | mutex_lock(&clk_lock); | |
a37462b9 | 58 | clk = v4l2_clk_find(dev_name(dev)); |
ff5430de GL |
59 | |
60 | if (!IS_ERR(clk)) | |
61 | atomic_inc(&clk->use_count); | |
62 | mutex_unlock(&clk_lock); | |
63 | ||
64 | return clk; | |
65 | } | |
66 | EXPORT_SYMBOL(v4l2_clk_get); | |
67 | ||
68 | void v4l2_clk_put(struct v4l2_clk *clk) | |
69 | { | |
70 | struct v4l2_clk *tmp; | |
71 | ||
72 | if (IS_ERR(clk)) | |
73 | return; | |
74 | ||
4f528afc GL |
75 | if (clk->clk) { |
76 | clk_put(clk->clk); | |
77 | kfree(clk); | |
78 | return; | |
79 | } | |
80 | ||
ff5430de GL |
81 | mutex_lock(&clk_lock); |
82 | ||
83 | list_for_each_entry(tmp, &clk_list, list) | |
84 | if (tmp == clk) | |
85 | atomic_dec(&clk->use_count); | |
86 | ||
87 | mutex_unlock(&clk_lock); | |
88 | } | |
89 | EXPORT_SYMBOL(v4l2_clk_put); | |
90 | ||
91 | static int v4l2_clk_lock_driver(struct v4l2_clk *clk) | |
92 | { | |
93 | struct v4l2_clk *tmp; | |
94 | int ret = -ENODEV; | |
95 | ||
96 | mutex_lock(&clk_lock); | |
97 | ||
98 | list_for_each_entry(tmp, &clk_list, list) | |
99 | if (tmp == clk) { | |
100 | ret = !try_module_get(clk->ops->owner); | |
101 | if (ret) | |
102 | ret = -EFAULT; | |
103 | break; | |
104 | } | |
105 | ||
106 | mutex_unlock(&clk_lock); | |
107 | ||
108 | return ret; | |
109 | } | |
110 | ||
111 | static void v4l2_clk_unlock_driver(struct v4l2_clk *clk) | |
112 | { | |
113 | module_put(clk->ops->owner); | |
114 | } | |
115 | ||
116 | int v4l2_clk_enable(struct v4l2_clk *clk) | |
117 | { | |
4f528afc GL |
118 | int ret; |
119 | ||
120 | if (clk->clk) | |
121 | return clk_prepare_enable(clk->clk); | |
ff5430de | 122 | |
4f528afc | 123 | ret = v4l2_clk_lock_driver(clk); |
ff5430de GL |
124 | if (ret < 0) |
125 | return ret; | |
126 | ||
127 | mutex_lock(&clk->lock); | |
128 | ||
129 | if (++clk->enable == 1 && clk->ops->enable) { | |
130 | ret = clk->ops->enable(clk); | |
131 | if (ret < 0) | |
132 | clk->enable--; | |
133 | } | |
134 | ||
135 | mutex_unlock(&clk->lock); | |
136 | ||
137 | return ret; | |
138 | } | |
139 | EXPORT_SYMBOL(v4l2_clk_enable); | |
140 | ||
141 | /* | |
142 | * You might Oops if you try to disabled a disabled clock, because then the | |
143 | * driver isn't locked and could have been unloaded by now, so, don't do that | |
144 | */ | |
145 | void v4l2_clk_disable(struct v4l2_clk *clk) | |
146 | { | |
147 | int enable; | |
148 | ||
4f528afc GL |
149 | if (clk->clk) |
150 | return clk_disable_unprepare(clk->clk); | |
151 | ||
ff5430de GL |
152 | mutex_lock(&clk->lock); |
153 | ||
154 | enable = --clk->enable; | |
a37462b9 GL |
155 | if (WARN(enable < 0, "Unbalanced %s() on %s!\n", __func__, |
156 | clk->dev_id)) | |
ff5430de GL |
157 | clk->enable++; |
158 | else if (!enable && clk->ops->disable) | |
159 | clk->ops->disable(clk); | |
160 | ||
161 | mutex_unlock(&clk->lock); | |
162 | ||
163 | v4l2_clk_unlock_driver(clk); | |
164 | } | |
165 | EXPORT_SYMBOL(v4l2_clk_disable); | |
166 | ||
167 | unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk) | |
168 | { | |
4f528afc GL |
169 | int ret; |
170 | ||
171 | if (clk->clk) | |
172 | return clk_get_rate(clk->clk); | |
ff5430de | 173 | |
4f528afc | 174 | ret = v4l2_clk_lock_driver(clk); |
ff5430de GL |
175 | if (ret < 0) |
176 | return ret; | |
177 | ||
178 | mutex_lock(&clk->lock); | |
179 | if (!clk->ops->get_rate) | |
180 | ret = -ENOSYS; | |
181 | else | |
182 | ret = clk->ops->get_rate(clk); | |
183 | mutex_unlock(&clk->lock); | |
184 | ||
185 | v4l2_clk_unlock_driver(clk); | |
186 | ||
187 | return ret; | |
188 | } | |
189 | EXPORT_SYMBOL(v4l2_clk_get_rate); | |
190 | ||
191 | int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate) | |
192 | { | |
4f528afc GL |
193 | int ret; |
194 | ||
195 | if (clk->clk) { | |
196 | long r = clk_round_rate(clk->clk, rate); | |
197 | if (r < 0) | |
198 | return r; | |
199 | return clk_set_rate(clk->clk, r); | |
200 | } | |
201 | ||
202 | ret = v4l2_clk_lock_driver(clk); | |
ff5430de GL |
203 | |
204 | if (ret < 0) | |
205 | return ret; | |
206 | ||
207 | mutex_lock(&clk->lock); | |
208 | if (!clk->ops->set_rate) | |
209 | ret = -ENOSYS; | |
210 | else | |
211 | ret = clk->ops->set_rate(clk, rate); | |
212 | mutex_unlock(&clk->lock); | |
213 | ||
214 | v4l2_clk_unlock_driver(clk); | |
215 | ||
216 | return ret; | |
217 | } | |
218 | EXPORT_SYMBOL(v4l2_clk_set_rate); | |
219 | ||
220 | struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops, | |
221 | const char *dev_id, | |
a37462b9 | 222 | void *priv) |
ff5430de GL |
223 | { |
224 | struct v4l2_clk *clk; | |
225 | int ret; | |
226 | ||
227 | if (!ops || !dev_id) | |
228 | return ERR_PTR(-EINVAL); | |
229 | ||
230 | clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL); | |
231 | if (!clk) | |
232 | return ERR_PTR(-ENOMEM); | |
233 | ||
ff5430de | 234 | clk->dev_id = kstrdup(dev_id, GFP_KERNEL); |
a37462b9 | 235 | if (!clk->dev_id) { |
ff5430de GL |
236 | ret = -ENOMEM; |
237 | goto ealloc; | |
238 | } | |
239 | clk->ops = ops; | |
240 | clk->priv = priv; | |
241 | atomic_set(&clk->use_count, 0); | |
242 | mutex_init(&clk->lock); | |
243 | ||
244 | mutex_lock(&clk_lock); | |
a37462b9 | 245 | if (!IS_ERR(v4l2_clk_find(dev_id))) { |
ff5430de GL |
246 | mutex_unlock(&clk_lock); |
247 | ret = -EEXIST; | |
248 | goto eexist; | |
249 | } | |
250 | list_add_tail(&clk->list, &clk_list); | |
251 | mutex_unlock(&clk_lock); | |
252 | ||
253 | return clk; | |
254 | ||
255 | eexist: | |
256 | ealloc: | |
ff5430de GL |
257 | kfree(clk->dev_id); |
258 | kfree(clk); | |
259 | return ERR_PTR(ret); | |
260 | } | |
261 | EXPORT_SYMBOL(v4l2_clk_register); | |
262 | ||
263 | void v4l2_clk_unregister(struct v4l2_clk *clk) | |
264 | { | |
265 | if (WARN(atomic_read(&clk->use_count), | |
a37462b9 GL |
266 | "%s(): Refusing to unregister ref-counted %s clock!\n", |
267 | __func__, clk->dev_id)) | |
ff5430de GL |
268 | return; |
269 | ||
270 | mutex_lock(&clk_lock); | |
271 | list_del(&clk->list); | |
272 | mutex_unlock(&clk_lock); | |
273 | ||
ff5430de GL |
274 | kfree(clk->dev_id); |
275 | kfree(clk); | |
276 | } | |
277 | EXPORT_SYMBOL(v4l2_clk_unregister); | |
cf326dfe GL |
278 | |
279 | struct v4l2_clk_fixed { | |
280 | unsigned long rate; | |
281 | struct v4l2_clk_ops ops; | |
282 | }; | |
283 | ||
284 | static unsigned long fixed_get_rate(struct v4l2_clk *clk) | |
285 | { | |
286 | struct v4l2_clk_fixed *priv = clk->priv; | |
287 | return priv->rate; | |
288 | } | |
289 | ||
290 | struct v4l2_clk *__v4l2_clk_register_fixed(const char *dev_id, | |
a37462b9 | 291 | unsigned long rate, struct module *owner) |
cf326dfe GL |
292 | { |
293 | struct v4l2_clk *clk; | |
294 | struct v4l2_clk_fixed *priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
295 | ||
296 | if (!priv) | |
297 | return ERR_PTR(-ENOMEM); | |
298 | ||
299 | priv->rate = rate; | |
300 | priv->ops.get_rate = fixed_get_rate; | |
301 | priv->ops.owner = owner; | |
302 | ||
a37462b9 | 303 | clk = v4l2_clk_register(&priv->ops, dev_id, priv); |
cf326dfe GL |
304 | if (IS_ERR(clk)) |
305 | kfree(priv); | |
306 | ||
307 | return clk; | |
308 | } | |
309 | EXPORT_SYMBOL(__v4l2_clk_register_fixed); | |
310 | ||
311 | void v4l2_clk_unregister_fixed(struct v4l2_clk *clk) | |
312 | { | |
313 | kfree(clk->priv); | |
314 | v4l2_clk_unregister(clk); | |
315 | } | |
316 | EXPORT_SYMBOL(v4l2_clk_unregister_fixed); |