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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; | |
61fc4131 PZ |
33 | unsigned int id; |
34 | }; | |
35 | ||
36 | /** | |
37 | * of_reset_simple_xlate - translate reset_spec to the reset line number | |
38 | * @rcdev: a pointer to the reset controller device | |
39 | * @reset_spec: reset line specifier as found in the device tree | |
40 | * @flags: a flags pointer to fill in (optional) | |
41 | * | |
42 | * This simple translation function should be used for reset controllers | |
43 | * with 1:1 mapping, where reset lines can be indexed by number without gaps. | |
44 | */ | |
0c5b2b91 | 45 | static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, |
61fc4131 PZ |
46 | const struct of_phandle_args *reset_spec) |
47 | { | |
48 | if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells)) | |
49 | return -EINVAL; | |
50 | ||
51 | if (reset_spec->args[0] >= rcdev->nr_resets) | |
52 | return -EINVAL; | |
53 | ||
54 | return reset_spec->args[0]; | |
55 | } | |
61fc4131 PZ |
56 | |
57 | /** | |
58 | * reset_controller_register - register a reset controller device | |
59 | * @rcdev: a pointer to the initialized reset controller device | |
60 | */ | |
61 | int reset_controller_register(struct reset_controller_dev *rcdev) | |
62 | { | |
63 | if (!rcdev->of_xlate) { | |
64 | rcdev->of_reset_n_cells = 1; | |
65 | rcdev->of_xlate = of_reset_simple_xlate; | |
66 | } | |
67 | ||
68 | mutex_lock(&reset_controller_list_mutex); | |
69 | list_add(&rcdev->list, &reset_controller_list); | |
70 | mutex_unlock(&reset_controller_list_mutex); | |
71 | ||
72 | return 0; | |
73 | } | |
74 | EXPORT_SYMBOL_GPL(reset_controller_register); | |
75 | ||
76 | /** | |
77 | * reset_controller_unregister - unregister a reset controller device | |
78 | * @rcdev: a pointer to the reset controller device | |
79 | */ | |
80 | void reset_controller_unregister(struct reset_controller_dev *rcdev) | |
81 | { | |
82 | mutex_lock(&reset_controller_list_mutex); | |
83 | list_del(&rcdev->list); | |
84 | mutex_unlock(&reset_controller_list_mutex); | |
85 | } | |
86 | EXPORT_SYMBOL_GPL(reset_controller_unregister); | |
87 | ||
88 | /** | |
89 | * reset_control_reset - reset the controlled device | |
90 | * @rstc: reset controller | |
91 | */ | |
92 | int reset_control_reset(struct reset_control *rstc) | |
93 | { | |
94 | if (rstc->rcdev->ops->reset) | |
95 | return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); | |
96 | ||
39b4da71 | 97 | return -ENOTSUPP; |
61fc4131 PZ |
98 | } |
99 | EXPORT_SYMBOL_GPL(reset_control_reset); | |
100 | ||
101 | /** | |
102 | * reset_control_assert - asserts the reset line | |
103 | * @rstc: reset controller | |
104 | */ | |
105 | int reset_control_assert(struct reset_control *rstc) | |
106 | { | |
107 | if (rstc->rcdev->ops->assert) | |
108 | return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); | |
109 | ||
39b4da71 | 110 | return -ENOTSUPP; |
61fc4131 PZ |
111 | } |
112 | EXPORT_SYMBOL_GPL(reset_control_assert); | |
113 | ||
114 | /** | |
115 | * reset_control_deassert - deasserts the reset line | |
116 | * @rstc: reset controller | |
117 | */ | |
118 | int reset_control_deassert(struct reset_control *rstc) | |
119 | { | |
120 | if (rstc->rcdev->ops->deassert) | |
121 | return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); | |
122 | ||
39b4da71 | 123 | return -ENOTSUPP; |
61fc4131 PZ |
124 | } |
125 | EXPORT_SYMBOL_GPL(reset_control_deassert); | |
126 | ||
729de41b DN |
127 | /** |
128 | * reset_control_status - returns a negative errno if not supported, a | |
129 | * positive value if the reset line is asserted, or zero if the reset | |
130 | * line is not asserted. | |
131 | * @rstc: reset controller | |
132 | */ | |
133 | int reset_control_status(struct reset_control *rstc) | |
134 | { | |
135 | if (rstc->rcdev->ops->status) | |
136 | return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); | |
137 | ||
39b4da71 | 138 | return -ENOTSUPP; |
729de41b DN |
139 | } |
140 | EXPORT_SYMBOL_GPL(reset_control_status); | |
141 | ||
61fc4131 | 142 | /** |
c0a13aa6 VH |
143 | * of_reset_control_get_by_index - Lookup and obtain a reference to a reset |
144 | * controller by index. | |
fc0a5921 | 145 | * @node: device to be reset by the controller |
c0a13aa6 | 146 | * @index: index of the reset controller |
61fc4131 | 147 | * |
c0a13aa6 VH |
148 | * This is to be used to perform a list of resets for a device or power domain |
149 | * in whatever order. Returns a struct reset_control or IS_ERR() condition | |
150 | * containing errno. | |
61fc4131 | 151 | */ |
c0a13aa6 VH |
152 | struct reset_control *of_reset_control_get_by_index(struct device_node *node, |
153 | int index) | |
61fc4131 PZ |
154 | { |
155 | struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); | |
156 | struct reset_controller_dev *r, *rcdev; | |
157 | struct of_phandle_args args; | |
61fc4131 PZ |
158 | int rstc_id; |
159 | int ret; | |
160 | ||
fc0a5921 | 161 | ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", |
61fc4131 PZ |
162 | index, &args); |
163 | if (ret) | |
164 | return ERR_PTR(ret); | |
165 | ||
166 | mutex_lock(&reset_controller_list_mutex); | |
167 | rcdev = NULL; | |
168 | list_for_each_entry(r, &reset_controller_list, list) { | |
169 | if (args.np == r->of_node) { | |
170 | rcdev = r; | |
171 | break; | |
172 | } | |
173 | } | |
174 | of_node_put(args.np); | |
175 | ||
176 | if (!rcdev) { | |
177 | mutex_unlock(&reset_controller_list_mutex); | |
3d103020 | 178 | return ERR_PTR(-EPROBE_DEFER); |
61fc4131 PZ |
179 | } |
180 | ||
181 | rstc_id = rcdev->of_xlate(rcdev, &args); | |
182 | if (rstc_id < 0) { | |
183 | mutex_unlock(&reset_controller_list_mutex); | |
184 | return ERR_PTR(rstc_id); | |
185 | } | |
186 | ||
187 | try_module_get(rcdev->owner); | |
188 | mutex_unlock(&reset_controller_list_mutex); | |
189 | ||
190 | rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); | |
191 | if (!rstc) { | |
6034bb22 | 192 | module_put(rcdev->owner); |
61fc4131 PZ |
193 | return ERR_PTR(-ENOMEM); |
194 | } | |
195 | ||
61fc4131 PZ |
196 | rstc->rcdev = rcdev; |
197 | rstc->id = rstc_id; | |
198 | ||
199 | return rstc; | |
200 | } | |
c0a13aa6 VH |
201 | EXPORT_SYMBOL_GPL(of_reset_control_get_by_index); |
202 | ||
203 | /** | |
204 | * of_reset_control_get - Lookup and obtain a reference to a reset controller. | |
205 | * @node: device to be reset by the controller | |
206 | * @id: reset line name | |
207 | * | |
208 | * Returns a struct reset_control or IS_ERR() condition containing errno. | |
209 | * | |
210 | * Use of id names is optional. | |
211 | */ | |
212 | struct reset_control *of_reset_control_get(struct device_node *node, | |
213 | const char *id) | |
214 | { | |
215 | int index = 0; | |
216 | ||
3d81216f | 217 | if (id) { |
c0a13aa6 VH |
218 | index = of_property_match_string(node, |
219 | "reset-names", id); | |
3d81216f AB |
220 | if (index < 0) |
221 | return ERR_PTR(-ENOENT); | |
222 | } | |
c0a13aa6 VH |
223 | return of_reset_control_get_by_index(node, index); |
224 | } | |
fc0a5921 MR |
225 | EXPORT_SYMBOL_GPL(of_reset_control_get); |
226 | ||
227 | /** | |
228 | * reset_control_get - Lookup and obtain a reference to a reset controller. | |
229 | * @dev: device to be reset by the controller | |
230 | * @id: reset line name | |
231 | * | |
232 | * Returns a struct reset_control or IS_ERR() condition containing errno. | |
233 | * | |
234 | * Use of id names is optional. | |
235 | */ | |
236 | struct reset_control *reset_control_get(struct device *dev, const char *id) | |
237 | { | |
fc0a5921 MR |
238 | if (!dev) |
239 | return ERR_PTR(-EINVAL); | |
240 | ||
b354f68f | 241 | return of_reset_control_get(dev->of_node, id); |
fc0a5921 | 242 | } |
61fc4131 PZ |
243 | EXPORT_SYMBOL_GPL(reset_control_get); |
244 | ||
245 | /** | |
246 | * reset_control_put - free the reset controller | |
247 | * @rstc: reset controller | |
248 | */ | |
249 | ||
250 | void reset_control_put(struct reset_control *rstc) | |
251 | { | |
252 | if (IS_ERR(rstc)) | |
253 | return; | |
254 | ||
255 | module_put(rstc->rcdev->owner); | |
256 | kfree(rstc); | |
257 | } | |
258 | EXPORT_SYMBOL_GPL(reset_control_put); | |
259 | ||
260 | static void devm_reset_control_release(struct device *dev, void *res) | |
261 | { | |
262 | reset_control_put(*(struct reset_control **)res); | |
263 | } | |
264 | ||
265 | /** | |
266 | * devm_reset_control_get - resource managed reset_control_get() | |
267 | * @dev: device to be reset by the controller | |
268 | * @id: reset line name | |
269 | * | |
270 | * Managed reset_control_get(). For reset controllers returned from this | |
271 | * function, reset_control_put() is called automatically on driver detach. | |
272 | * See reset_control_get() for more information. | |
273 | */ | |
274 | struct reset_control *devm_reset_control_get(struct device *dev, const char *id) | |
275 | { | |
276 | struct reset_control **ptr, *rstc; | |
277 | ||
278 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), | |
279 | GFP_KERNEL); | |
280 | if (!ptr) | |
281 | return ERR_PTR(-ENOMEM); | |
282 | ||
283 | rstc = reset_control_get(dev, id); | |
284 | if (!IS_ERR(rstc)) { | |
285 | *ptr = rstc; | |
286 | devres_add(dev, ptr); | |
287 | } else { | |
288 | devres_free(ptr); | |
289 | } | |
290 | ||
291 | return rstc; | |
292 | } | |
293 | EXPORT_SYMBOL_GPL(devm_reset_control_get); | |
294 | ||
61fc4131 PZ |
295 | /** |
296 | * device_reset - find reset controller associated with the device | |
297 | * and perform reset | |
298 | * @dev: device to be reset by the controller | |
299 | * | |
300 | * Convenience wrapper for reset_control_get() and reset_control_reset(). | |
301 | * This is useful for the common case of devices with single, dedicated reset | |
302 | * lines. | |
303 | */ | |
304 | int device_reset(struct device *dev) | |
305 | { | |
306 | struct reset_control *rstc; | |
307 | int ret; | |
308 | ||
309 | rstc = reset_control_get(dev, NULL); | |
310 | if (IS_ERR(rstc)) | |
311 | return PTR_ERR(rstc); | |
312 | ||
313 | ret = reset_control_reset(rstc); | |
314 | ||
315 | reset_control_put(rstc); | |
316 | ||
317 | return ret; | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(device_reset); |