blob: baeaf82d40d9f1982761d68ee1cf0c56cd6c346e [file] [log] [blame]
Philipp Zabel61fc4132012-11-19 17:23:13 +01001/*
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
21static DEFINE_MUTEX(reset_controller_list_mutex);
22static 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 */
31struct 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 */
Rashika Kheria0c5b2b92013-12-19 14:11:10 +053046static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
Philipp Zabel61fc4132012-11-19 17:23:13 +010047 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}
Philipp Zabel61fc4132012-11-19 17:23:13 +010057
58/**
59 * reset_controller_register - register a reset controller device
60 * @rcdev: a pointer to the initialized reset controller device
61 */
62int reset_controller_register(struct reset_controller_dev *rcdev)
63{
64 if (!rcdev->of_xlate) {
65 rcdev->of_reset_n_cells = 1;
66 rcdev->of_xlate = of_reset_simple_xlate;
67 }
68
69 mutex_lock(&reset_controller_list_mutex);
70 list_add(&rcdev->list, &reset_controller_list);
71 mutex_unlock(&reset_controller_list_mutex);
72
73 return 0;
74}
75EXPORT_SYMBOL_GPL(reset_controller_register);
76
77/**
78 * reset_controller_unregister - unregister a reset controller device
79 * @rcdev: a pointer to the reset controller device
80 */
81void reset_controller_unregister(struct reset_controller_dev *rcdev)
82{
83 mutex_lock(&reset_controller_list_mutex);
84 list_del(&rcdev->list);
85 mutex_unlock(&reset_controller_list_mutex);
86}
87EXPORT_SYMBOL_GPL(reset_controller_unregister);
88
89/**
90 * reset_control_reset - reset the controlled device
91 * @rstc: reset controller
92 */
93int reset_control_reset(struct reset_control *rstc)
94{
95 if (rstc->rcdev->ops->reset)
96 return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
97
98 return -ENOSYS;
99}
100EXPORT_SYMBOL_GPL(reset_control_reset);
101
102/**
103 * reset_control_assert - asserts the reset line
104 * @rstc: reset controller
105 */
106int reset_control_assert(struct reset_control *rstc)
107{
108 if (rstc->rcdev->ops->assert)
109 return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
110
111 return -ENOSYS;
112}
113EXPORT_SYMBOL_GPL(reset_control_assert);
114
115/**
116 * reset_control_deassert - deasserts the reset line
117 * @rstc: reset controller
118 */
119int reset_control_deassert(struct reset_control *rstc)
120{
121 if (rstc->rcdev->ops->deassert)
122 return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
123
124 return -ENOSYS;
125}
126EXPORT_SYMBOL_GPL(reset_control_deassert);
127
128/**
Maxime Ripardfc0a5922013-12-20 22:41:07 +0100129 * of_reset_control_get - Lookup and obtain a reference to a reset controller.
130 * @node: device to be reset by the controller
Philipp Zabel61fc4132012-11-19 17:23:13 +0100131 * @id: reset line name
132 *
133 * Returns a struct reset_control or IS_ERR() condition containing errno.
134 *
135 * Use of id names is optional.
136 */
Maxime Ripardfc0a5922013-12-20 22:41:07 +0100137struct reset_control *of_reset_control_get(struct device_node *node,
138 const char *id)
Philipp Zabel61fc4132012-11-19 17:23:13 +0100139{
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
Philipp Zabel61fc4132012-11-19 17:23:13 +0100147 if (id)
Maxime Ripardfc0a5922013-12-20 22:41:07 +0100148 index = of_property_match_string(node,
Philipp Zabel61fc4132012-11-19 17:23:13 +0100149 "reset-names", id);
Maxime Ripardfc0a5922013-12-20 22:41:07 +0100150 ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
Philipp Zabel61fc4132012-11-19 17:23:13 +0100151 index, &args);
152 if (ret)
153 return ERR_PTR(ret);
154
155 mutex_lock(&reset_controller_list_mutex);
156 rcdev = NULL;
157 list_for_each_entry(r, &reset_controller_list, list) {
158 if (args.np == r->of_node) {
159 rcdev = r;
160 break;
161 }
162 }
163 of_node_put(args.np);
164
165 if (!rcdev) {
166 mutex_unlock(&reset_controller_list_mutex);
Philipp Zabel3d103022013-07-18 13:55:22 +0200167 return ERR_PTR(-EPROBE_DEFER);
Philipp Zabel61fc4132012-11-19 17:23:13 +0100168 }
169
170 rstc_id = rcdev->of_xlate(rcdev, &args);
171 if (rstc_id < 0) {
172 mutex_unlock(&reset_controller_list_mutex);
173 return ERR_PTR(rstc_id);
174 }
175
176 try_module_get(rcdev->owner);
177 mutex_unlock(&reset_controller_list_mutex);
178
179 rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
180 if (!rstc) {
Dan Carpenter6034bb22013-04-03 08:02:53 +0300181 module_put(rcdev->owner);
Philipp Zabel61fc4132012-11-19 17:23:13 +0100182 return ERR_PTR(-ENOMEM);
183 }
184
Philipp Zabel61fc4132012-11-19 17:23:13 +0100185 rstc->rcdev = rcdev;
186 rstc->id = rstc_id;
187
188 return rstc;
189}
Maxime Ripardfc0a5922013-12-20 22:41:07 +0100190EXPORT_SYMBOL_GPL(of_reset_control_get);
191
192/**
193 * reset_control_get - Lookup and obtain a reference to a reset controller.
194 * @dev: device to be reset by the controller
195 * @id: reset line name
196 *
197 * Returns a struct reset_control or IS_ERR() condition containing errno.
198 *
199 * Use of id names is optional.
200 */
201struct reset_control *reset_control_get(struct device *dev, const char *id)
202{
203 struct reset_control *rstc;
204
205 if (!dev)
206 return ERR_PTR(-EINVAL);
207
208 rstc = of_reset_control_get(dev->of_node, id);
209 if (!IS_ERR(rstc))
210 rstc->dev = dev;
211
212 return rstc;
213}
Philipp Zabel61fc4132012-11-19 17:23:13 +0100214EXPORT_SYMBOL_GPL(reset_control_get);
215
216/**
217 * reset_control_put - free the reset controller
218 * @rstc: reset controller
219 */
220
221void reset_control_put(struct reset_control *rstc)
222{
223 if (IS_ERR(rstc))
224 return;
225
226 module_put(rstc->rcdev->owner);
227 kfree(rstc);
228}
229EXPORT_SYMBOL_GPL(reset_control_put);
230
231static void devm_reset_control_release(struct device *dev, void *res)
232{
233 reset_control_put(*(struct reset_control **)res);
234}
235
236/**
237 * devm_reset_control_get - resource managed reset_control_get()
238 * @dev: device to be reset by the controller
239 * @id: reset line name
240 *
241 * Managed reset_control_get(). For reset controllers returned from this
242 * function, reset_control_put() is called automatically on driver detach.
243 * See reset_control_get() for more information.
244 */
245struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
246{
247 struct reset_control **ptr, *rstc;
248
249 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
250 GFP_KERNEL);
251 if (!ptr)
252 return ERR_PTR(-ENOMEM);
253
254 rstc = reset_control_get(dev, id);
255 if (!IS_ERR(rstc)) {
256 *ptr = rstc;
257 devres_add(dev, ptr);
258 } else {
259 devres_free(ptr);
260 }
261
262 return rstc;
263}
264EXPORT_SYMBOL_GPL(devm_reset_control_get);
265
Philipp Zabel61fc4132012-11-19 17:23:13 +0100266/**
267 * device_reset - find reset controller associated with the device
268 * and perform reset
269 * @dev: device to be reset by the controller
270 *
271 * Convenience wrapper for reset_control_get() and reset_control_reset().
272 * This is useful for the common case of devices with single, dedicated reset
273 * lines.
274 */
275int device_reset(struct device *dev)
276{
277 struct reset_control *rstc;
278 int ret;
279
280 rstc = reset_control_get(dev, NULL);
281 if (IS_ERR(rstc))
282 return PTR_ERR(rstc);
283
284 ret = reset_control_reset(rstc);
285
286 reset_control_put(rstc);
287
288 return ret;
289}
290EXPORT_SYMBOL_GPL(device_reset);