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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 | { | |
61fc4131 PZ |
48 | if (reset_spec->args[0] >= rcdev->nr_resets) |
49 | return -EINVAL; | |
50 | ||
51 | return reset_spec->args[0]; | |
52 | } | |
61fc4131 PZ |
53 | |
54 | /** | |
55 | * reset_controller_register - register a reset controller device | |
56 | * @rcdev: a pointer to the initialized reset controller device | |
57 | */ | |
58 | int reset_controller_register(struct reset_controller_dev *rcdev) | |
59 | { | |
60 | if (!rcdev->of_xlate) { | |
61 | rcdev->of_reset_n_cells = 1; | |
62 | rcdev->of_xlate = of_reset_simple_xlate; | |
63 | } | |
64 | ||
65 | mutex_lock(&reset_controller_list_mutex); | |
66 | list_add(&rcdev->list, &reset_controller_list); | |
67 | mutex_unlock(&reset_controller_list_mutex); | |
68 | ||
69 | return 0; | |
70 | } | |
71 | EXPORT_SYMBOL_GPL(reset_controller_register); | |
72 | ||
73 | /** | |
74 | * reset_controller_unregister - unregister a reset controller device | |
75 | * @rcdev: a pointer to the reset controller device | |
76 | */ | |
77 | void reset_controller_unregister(struct reset_controller_dev *rcdev) | |
78 | { | |
79 | mutex_lock(&reset_controller_list_mutex); | |
80 | list_del(&rcdev->list); | |
81 | mutex_unlock(&reset_controller_list_mutex); | |
82 | } | |
83 | EXPORT_SYMBOL_GPL(reset_controller_unregister); | |
84 | ||
85 | /** | |
86 | * reset_control_reset - reset the controlled device | |
87 | * @rstc: reset controller | |
88 | */ | |
89 | int reset_control_reset(struct reset_control *rstc) | |
90 | { | |
91 | if (rstc->rcdev->ops->reset) | |
92 | return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); | |
93 | ||
39b4da71 | 94 | return -ENOTSUPP; |
61fc4131 PZ |
95 | } |
96 | EXPORT_SYMBOL_GPL(reset_control_reset); | |
97 | ||
98 | /** | |
99 | * reset_control_assert - asserts the reset line | |
100 | * @rstc: reset controller | |
101 | */ | |
102 | int reset_control_assert(struct reset_control *rstc) | |
103 | { | |
104 | if (rstc->rcdev->ops->assert) | |
105 | return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); | |
106 | ||
39b4da71 | 107 | return -ENOTSUPP; |
61fc4131 PZ |
108 | } |
109 | EXPORT_SYMBOL_GPL(reset_control_assert); | |
110 | ||
111 | /** | |
112 | * reset_control_deassert - deasserts the reset line | |
113 | * @rstc: reset controller | |
114 | */ | |
115 | int reset_control_deassert(struct reset_control *rstc) | |
116 | { | |
117 | if (rstc->rcdev->ops->deassert) | |
118 | return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); | |
119 | ||
39b4da71 | 120 | return -ENOTSUPP; |
61fc4131 PZ |
121 | } |
122 | EXPORT_SYMBOL_GPL(reset_control_deassert); | |
123 | ||
729de41b DN |
124 | /** |
125 | * reset_control_status - returns a negative errno if not supported, a | |
126 | * positive value if the reset line is asserted, or zero if the reset | |
127 | * line is not asserted. | |
128 | * @rstc: reset controller | |
129 | */ | |
130 | int reset_control_status(struct reset_control *rstc) | |
131 | { | |
132 | if (rstc->rcdev->ops->status) | |
133 | return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); | |
134 | ||
39b4da71 | 135 | return -ENOTSUPP; |
729de41b DN |
136 | } |
137 | EXPORT_SYMBOL_GPL(reset_control_status); | |
138 | ||
61fc4131 | 139 | /** |
c0a13aa6 VH |
140 | * of_reset_control_get_by_index - Lookup and obtain a reference to a reset |
141 | * controller by index. | |
fc0a5921 | 142 | * @node: device to be reset by the controller |
c0a13aa6 | 143 | * @index: index of the reset controller |
61fc4131 | 144 | * |
c0a13aa6 VH |
145 | * This is to be used to perform a list of resets for a device or power domain |
146 | * in whatever order. Returns a struct reset_control or IS_ERR() condition | |
147 | * containing errno. | |
61fc4131 | 148 | */ |
c0a13aa6 VH |
149 | struct reset_control *of_reset_control_get_by_index(struct device_node *node, |
150 | int index) | |
61fc4131 | 151 | { |
d056c9b8 | 152 | struct reset_control *rstc; |
61fc4131 PZ |
153 | struct reset_controller_dev *r, *rcdev; |
154 | struct of_phandle_args args; | |
61fc4131 PZ |
155 | int rstc_id; |
156 | int ret; | |
157 | ||
fc0a5921 | 158 | ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", |
61fc4131 PZ |
159 | index, &args); |
160 | if (ret) | |
161 | return ERR_PTR(ret); | |
162 | ||
163 | mutex_lock(&reset_controller_list_mutex); | |
164 | rcdev = NULL; | |
165 | list_for_each_entry(r, &reset_controller_list, list) { | |
166 | if (args.np == r->of_node) { | |
167 | rcdev = r; | |
168 | break; | |
169 | } | |
170 | } | |
171 | of_node_put(args.np); | |
172 | ||
173 | if (!rcdev) { | |
174 | mutex_unlock(&reset_controller_list_mutex); | |
3d103020 | 175 | return ERR_PTR(-EPROBE_DEFER); |
61fc4131 PZ |
176 | } |
177 | ||
e677774f MR |
178 | if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { |
179 | mutex_unlock(&reset_controller_list_mutex); | |
180 | return ERR_PTR(-EINVAL); | |
181 | } | |
182 | ||
61fc4131 PZ |
183 | rstc_id = rcdev->of_xlate(rcdev, &args); |
184 | if (rstc_id < 0) { | |
185 | mutex_unlock(&reset_controller_list_mutex); | |
186 | return ERR_PTR(rstc_id); | |
187 | } | |
188 | ||
189 | try_module_get(rcdev->owner); | |
190 | mutex_unlock(&reset_controller_list_mutex); | |
191 | ||
192 | rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); | |
193 | if (!rstc) { | |
6034bb22 | 194 | module_put(rcdev->owner); |
61fc4131 PZ |
195 | return ERR_PTR(-ENOMEM); |
196 | } | |
197 | ||
61fc4131 PZ |
198 | rstc->rcdev = rcdev; |
199 | rstc->id = rstc_id; | |
200 | ||
201 | return rstc; | |
202 | } | |
c0a13aa6 VH |
203 | EXPORT_SYMBOL_GPL(of_reset_control_get_by_index); |
204 | ||
205 | /** | |
206 | * of_reset_control_get - Lookup and obtain a reference to a reset controller. | |
207 | * @node: device to be reset by the controller | |
208 | * @id: reset line name | |
209 | * | |
210 | * Returns a struct reset_control or IS_ERR() condition containing errno. | |
211 | * | |
212 | * Use of id names is optional. | |
213 | */ | |
214 | struct reset_control *of_reset_control_get(struct device_node *node, | |
215 | const char *id) | |
216 | { | |
217 | int index = 0; | |
218 | ||
3d81216f | 219 | if (id) { |
c0a13aa6 VH |
220 | index = of_property_match_string(node, |
221 | "reset-names", id); | |
3d81216f AB |
222 | if (index < 0) |
223 | return ERR_PTR(-ENOENT); | |
224 | } | |
c0a13aa6 VH |
225 | return of_reset_control_get_by_index(node, index); |
226 | } | |
fc0a5921 MR |
227 | EXPORT_SYMBOL_GPL(of_reset_control_get); |
228 | ||
229 | /** | |
230 | * reset_control_get - Lookup and obtain a reference to a reset controller. | |
231 | * @dev: device to be reset by the controller | |
232 | * @id: reset line name | |
233 | * | |
234 | * Returns a struct reset_control or IS_ERR() condition containing errno. | |
235 | * | |
236 | * Use of id names is optional. | |
237 | */ | |
238 | struct reset_control *reset_control_get(struct device *dev, const char *id) | |
239 | { | |
fc0a5921 MR |
240 | if (!dev) |
241 | return ERR_PTR(-EINVAL); | |
242 | ||
b354f68f | 243 | return of_reset_control_get(dev->of_node, id); |
fc0a5921 | 244 | } |
61fc4131 PZ |
245 | EXPORT_SYMBOL_GPL(reset_control_get); |
246 | ||
247 | /** | |
248 | * reset_control_put - free the reset controller | |
249 | * @rstc: reset controller | |
250 | */ | |
251 | ||
252 | void reset_control_put(struct reset_control *rstc) | |
253 | { | |
254 | if (IS_ERR(rstc)) | |
255 | return; | |
256 | ||
257 | module_put(rstc->rcdev->owner); | |
258 | kfree(rstc); | |
259 | } | |
260 | EXPORT_SYMBOL_GPL(reset_control_put); | |
261 | ||
262 | static void devm_reset_control_release(struct device *dev, void *res) | |
263 | { | |
264 | reset_control_put(*(struct reset_control **)res); | |
265 | } | |
266 | ||
267 | /** | |
268 | * devm_reset_control_get - resource managed reset_control_get() | |
269 | * @dev: device to be reset by the controller | |
270 | * @id: reset line name | |
271 | * | |
272 | * Managed reset_control_get(). For reset controllers returned from this | |
273 | * function, reset_control_put() is called automatically on driver detach. | |
274 | * See reset_control_get() for more information. | |
275 | */ | |
276 | struct reset_control *devm_reset_control_get(struct device *dev, const char *id) | |
277 | { | |
278 | struct reset_control **ptr, *rstc; | |
279 | ||
280 | ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), | |
281 | GFP_KERNEL); | |
282 | if (!ptr) | |
283 | return ERR_PTR(-ENOMEM); | |
284 | ||
285 | rstc = reset_control_get(dev, id); | |
286 | if (!IS_ERR(rstc)) { | |
287 | *ptr = rstc; | |
288 | devres_add(dev, ptr); | |
289 | } else { | |
290 | devres_free(ptr); | |
291 | } | |
292 | ||
293 | return rstc; | |
294 | } | |
295 | EXPORT_SYMBOL_GPL(devm_reset_control_get); | |
296 | ||
61fc4131 PZ |
297 | /** |
298 | * device_reset - find reset controller associated with the device | |
299 | * and perform reset | |
300 | * @dev: device to be reset by the controller | |
301 | * | |
302 | * Convenience wrapper for reset_control_get() and reset_control_reset(). | |
303 | * This is useful for the common case of devices with single, dedicated reset | |
304 | * lines. | |
305 | */ | |
306 | int device_reset(struct device *dev) | |
307 | { | |
308 | struct reset_control *rstc; | |
309 | int ret; | |
310 | ||
311 | rstc = reset_control_get(dev, NULL); | |
312 | if (IS_ERR(rstc)) | |
313 | return PTR_ERR(rstc); | |
314 | ||
315 | ret = reset_control_reset(rstc); | |
316 | ||
317 | reset_control_put(rstc); | |
318 | ||
319 | return ret; | |
320 | } | |
321 | EXPORT_SYMBOL_GPL(device_reset); |