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61fc4131 PZ |
1 | /* |
2 | * Reset Controller framework | |
3 | * | |
4 | * Copyright 2013 Philipp Zabel, Pengutronix | |
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 as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | */ | |
11 | #include <linux/device.h> | |
12 | #include <linux/err.h> | |
13 | #include <linux/export.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/of.h> | |
17 | #include <linux/reset.h> | |
18 | #include <linux/reset-controller.h> | |
19 | #include <linux/slab.h> | |
20 | ||
21 | static DEFINE_MUTEX(reset_controller_list_mutex); | |
22 | static LIST_HEAD(reset_controller_list); | |
23 | ||
24 | /** | |
25 | * struct reset_control - a reset control | |
26 | * @rcdev: a pointer to the reset controller device | |
27 | * this reset control belongs to | |
28 | * @id: ID of the reset controller in the reset | |
29 | * controller device | |
30 | */ | |
31 | struct reset_control { | |
32 | struct reset_controller_dev *rcdev; | |
33 | struct device *dev; | |
34 | unsigned int id; | |
35 | }; | |
36 | ||
37 | /** | |
38 | * of_reset_simple_xlate - translate reset_spec to the reset line number | |
39 | * @rcdev: a pointer to the reset controller device | |
40 | * @reset_spec: reset line specifier as found in the device tree | |
41 | * @flags: a flags pointer to fill in (optional) | |
42 | * | |
43 | * This simple translation function should be used for reset controllers | |
44 | * with 1:1 mapping, where reset lines can be indexed by number without gaps. | |
45 | */ | |
46 | int of_reset_simple_xlate(struct reset_controller_dev *rcdev, | |
47 | const struct of_phandle_args *reset_spec) | |
48 | { | |
49 | if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells)) | |
50 | return -EINVAL; | |
51 | ||
52 | if (reset_spec->args[0] >= rcdev->nr_resets) | |
53 | return -EINVAL; | |
54 | ||
55 | return reset_spec->args[0]; | |
56 | } | |
57 | EXPORT_SYMBOL_GPL(of_reset_simple_xlate); | |
58 | ||
59 | /** | |
60 | * reset_controller_register - register a reset controller device | |
61 | * @rcdev: a pointer to the initialized reset controller device | |
62 | */ | |
63 | int reset_controller_register(struct reset_controller_dev *rcdev) | |
64 | { | |
65 | if (!rcdev->of_xlate) { | |
66 | rcdev->of_reset_n_cells = 1; | |
67 | rcdev->of_xlate = of_reset_simple_xlate; | |
68 | } | |
69 | ||
70 | mutex_lock(&reset_controller_list_mutex); | |
71 | list_add(&rcdev->list, &reset_controller_list); | |
72 | mutex_unlock(&reset_controller_list_mutex); | |
73 | ||
74 | return 0; | |
75 | } | |
76 | EXPORT_SYMBOL_GPL(reset_controller_register); | |
77 | ||
78 | /** | |
79 | * reset_controller_unregister - unregister a reset controller device | |
80 | * @rcdev: a pointer to the reset controller device | |
81 | */ | |
82 | void reset_controller_unregister(struct reset_controller_dev *rcdev) | |
83 | { | |
84 | mutex_lock(&reset_controller_list_mutex); | |
85 | list_del(&rcdev->list); | |
86 | mutex_unlock(&reset_controller_list_mutex); | |
87 | } | |
88 | EXPORT_SYMBOL_GPL(reset_controller_unregister); | |
89 | ||
90 | /** | |
91 | * reset_control_reset - reset the controlled device | |
92 | * @rstc: reset controller | |
93 | */ | |
94 | int reset_control_reset(struct reset_control *rstc) | |
95 | { | |
96 | if (rstc->rcdev->ops->reset) | |
97 | return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); | |
98 | ||
99 | return -ENOSYS; | |
100 | } | |
101 | EXPORT_SYMBOL_GPL(reset_control_reset); | |
102 | ||
103 | /** | |
104 | * reset_control_assert - asserts the reset line | |
105 | * @rstc: reset controller | |
106 | */ | |
107 | int reset_control_assert(struct reset_control *rstc) | |
108 | { | |
109 | if (rstc->rcdev->ops->assert) | |
110 | return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); | |
111 | ||
112 | return -ENOSYS; | |
113 | } | |
114 | EXPORT_SYMBOL_GPL(reset_control_assert); | |
115 | ||
116 | /** | |
117 | * reset_control_deassert - deasserts the reset line | |
118 | * @rstc: reset controller | |
119 | */ | |
120 | int reset_control_deassert(struct reset_control *rstc) | |
121 | { | |
122 | if (rstc->rcdev->ops->deassert) | |
123 | return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); | |
124 | ||
125 | return -ENOSYS; | |
126 | } | |
127 | EXPORT_SYMBOL_GPL(reset_control_deassert); | |
128 | ||
129 | /** | |
130 | * reset_control_get - Lookup and obtain a reference to a reset controller. | |
131 | * @dev: device to be reset by the controller | |
132 | * @id: reset line name | |
133 | * | |
134 | * Returns a struct reset_control or IS_ERR() condition containing errno. | |
135 | * | |
136 | * Use of id names is optional. | |
137 | */ | |
138 | struct reset_control *reset_control_get(struct device *dev, const char *id) | |
139 | { | |
140 | struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); | |
141 | struct reset_controller_dev *r, *rcdev; | |
142 | struct of_phandle_args args; | |
143 | int index = 0; | |
144 | int rstc_id; | |
145 | int ret; | |
146 | ||
147 | if (!dev) | |
148 | return ERR_PTR(-EINVAL); | |
149 | ||
150 | if (id) | |
151 | index = of_property_match_string(dev->of_node, | |
152 | "reset-names", id); | |
153 | ret = of_parse_phandle_with_args(dev->of_node, "resets", "#reset-cells", | |
154 | index, &args); | |
155 | if (ret) | |
156 | return ERR_PTR(ret); | |
157 | ||
158 | mutex_lock(&reset_controller_list_mutex); | |
159 | rcdev = NULL; | |
160 | list_for_each_entry(r, &reset_controller_list, list) { | |
161 | if (args.np == r->of_node) { | |
162 | rcdev = r; | |
163 | break; | |
164 | } | |
165 | } | |
166 | of_node_put(args.np); | |
167 | ||
168 | if (!rcdev) { | |
169 | mutex_unlock(&reset_controller_list_mutex); | |
3d103020 | 170 | return ERR_PTR(-EPROBE_DEFER); |
61fc4131 PZ |
171 | } |
172 | ||
173 | rstc_id = rcdev->of_xlate(rcdev, &args); | |
174 | if (rstc_id < 0) { | |
175 | mutex_unlock(&reset_controller_list_mutex); | |
176 | return ERR_PTR(rstc_id); | |
177 | } | |
178 | ||
179 | try_module_get(rcdev->owner); | |
180 | mutex_unlock(&reset_controller_list_mutex); | |
181 | ||
182 | rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); | |
183 | if (!rstc) { | |
6034bb22 | 184 | module_put(rcdev->owner); |
61fc4131 PZ |
185 | return ERR_PTR(-ENOMEM); |
186 | } | |
187 | ||
188 | rstc->dev = dev; | |
189 | rstc->rcdev = rcdev; | |
190 | rstc->id = rstc_id; | |
191 | ||
192 | return rstc; | |
193 | } | |
194 | EXPORT_SYMBOL_GPL(reset_control_get); | |
195 | ||
196 | /** | |
197 | * reset_control_put - free the reset controller | |
198 | * @rstc: reset controller | |
199 | */ | |
200 | ||
201 | void reset_control_put(struct reset_control *rstc) | |
202 | { | |
203 | if (IS_ERR(rstc)) | |
204 | return; | |
205 | ||
206 | module_put(rstc->rcdev->owner); | |
207 | kfree(rstc); | |
208 | } | |
209 | EXPORT_SYMBOL_GPL(reset_control_put); | |
210 | ||
211 | static void devm_reset_control_release(struct device *dev, void *res) | |
212 | { | |
213 | reset_control_put(*(struct reset_control **)res); | |
214 | } | |
215 | ||
216 | /** | |
217 | * devm_reset_control_get - resource managed reset_control_get() | |
218 | * @dev: device to be reset by the controller | |
219 | * @id: reset line name | |
220 | * | |
221 | * Managed reset_control_get(). For reset controllers returned from this | |
222 | * function, reset_control_put() is called automatically on driver detach. | |
223 | * See reset_control_get() for more information. | |
224 | */ | |
225 | struct reset_control *devm_reset_control_get(struct device *dev, const char *id) | |
226 | { | |
227 | struct reset_control **ptr, *rstc; | |
228 | ||
229 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), | |
230 | GFP_KERNEL); | |
231 | if (!ptr) | |
232 | return ERR_PTR(-ENOMEM); | |
233 | ||
234 | rstc = reset_control_get(dev, id); | |
235 | if (!IS_ERR(rstc)) { | |
236 | *ptr = rstc; | |
237 | devres_add(dev, ptr); | |
238 | } else { | |
239 | devres_free(ptr); | |
240 | } | |
241 | ||
242 | return rstc; | |
243 | } | |
244 | EXPORT_SYMBOL_GPL(devm_reset_control_get); | |
245 | ||
246 | static int devm_reset_control_match(struct device *dev, void *res, void *data) | |
247 | { | |
248 | struct reset_control **rstc = res; | |
249 | if (WARN_ON(!rstc || !*rstc)) | |
250 | return 0; | |
251 | return *rstc == data; | |
252 | } | |
253 | ||
254 | /** | |
255 | * devm_reset_control_put - resource managed reset_control_put() | |
256 | * @rstc: reset controller to free | |
257 | * | |
258 | * Deallocate a reset control allocated withd devm_reset_control_get(). | |
259 | * This function will not need to be called normally, as devres will take | |
260 | * care of freeing the resource. | |
261 | */ | |
262 | void devm_reset_control_put(struct reset_control *rstc) | |
263 | { | |
264 | int ret; | |
265 | ||
266 | ret = devres_release(rstc->dev, devm_reset_control_release, | |
267 | devm_reset_control_match, rstc); | |
268 | if (ret) | |
269 | WARN_ON(ret); | |
270 | } | |
271 | EXPORT_SYMBOL_GPL(devm_reset_control_put); | |
272 | ||
273 | /** | |
274 | * device_reset - find reset controller associated with the device | |
275 | * and perform reset | |
276 | * @dev: device to be reset by the controller | |
277 | * | |
278 | * Convenience wrapper for reset_control_get() and reset_control_reset(). | |
279 | * This is useful for the common case of devices with single, dedicated reset | |
280 | * lines. | |
281 | */ | |
282 | int device_reset(struct device *dev) | |
283 | { | |
284 | struct reset_control *rstc; | |
285 | int ret; | |
286 | ||
287 | rstc = reset_control_get(dev, NULL); | |
288 | if (IS_ERR(rstc)) | |
289 | return PTR_ERR(rstc); | |
290 | ||
291 | ret = reset_control_reset(rstc); | |
292 | ||
293 | reset_control_put(rstc); | |
294 | ||
295 | return ret; | |
296 | } | |
297 | EXPORT_SYMBOL_GPL(device_reset); |