Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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; |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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 | */ |
Rashika Kheria | 0c5b2b9 | 2013-12-19 14:11:10 +0530 | [diff] [blame] | 45 | static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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 | } |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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 | |
Philipp Zabel | 39b4da7 | 2015-10-29 09:55:00 +0100 | [diff] [blame] | 97 | return -ENOTSUPP; |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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 | |
Philipp Zabel | 39b4da7 | 2015-10-29 09:55:00 +0100 | [diff] [blame] | 110 | return -ENOTSUPP; |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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 | |
Philipp Zabel | 39b4da7 | 2015-10-29 09:55:00 +0100 | [diff] [blame] | 123 | return -ENOTSUPP; |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 124 | } |
| 125 | EXPORT_SYMBOL_GPL(reset_control_deassert); |
| 126 | |
| 127 | /** |
Dinh Nguyen | 729de41 | 2014-10-10 10:21:14 -0500 | [diff] [blame] | 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 | |
Philipp Zabel | 39b4da7 | 2015-10-29 09:55:00 +0100 | [diff] [blame] | 138 | return -ENOTSUPP; |
Dinh Nguyen | 729de41 | 2014-10-10 10:21:14 -0500 | [diff] [blame] | 139 | } |
| 140 | EXPORT_SYMBOL_GPL(reset_control_status); |
| 141 | |
| 142 | /** |
Vince Hsu | c0a13aa | 2015-07-13 13:39:39 +0100 | [diff] [blame] | 143 | * of_reset_control_get_by_index - Lookup and obtain a reference to a reset |
| 144 | * controller by index. |
Maxime Ripard | fc0a592 | 2013-12-20 22:41:07 +0100 | [diff] [blame] | 145 | * @node: device to be reset by the controller |
Vince Hsu | c0a13aa | 2015-07-13 13:39:39 +0100 | [diff] [blame] | 146 | * @index: index of the reset controller |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 147 | * |
Vince Hsu | c0a13aa | 2015-07-13 13:39:39 +0100 | [diff] [blame] | 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. |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 151 | */ |
Vince Hsu | c0a13aa | 2015-07-13 13:39:39 +0100 | [diff] [blame] | 152 | struct reset_control *of_reset_control_get_by_index(struct device_node *node, |
| 153 | int index) |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 154 | { |
| 155 | struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); |
| 156 | struct reset_controller_dev *r, *rcdev; |
| 157 | struct of_phandle_args args; |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 158 | int rstc_id; |
| 159 | int ret; |
| 160 | |
Maxime Ripard | fc0a592 | 2013-12-20 22:41:07 +0100 | [diff] [blame] | 161 | ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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); |
Philipp Zabel | 3d10302 | 2013-07-18 13:55:22 +0200 | [diff] [blame] | 178 | return ERR_PTR(-EPROBE_DEFER); |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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) { |
Dan Carpenter | 6034bb2 | 2013-04-03 08:02:53 +0300 | [diff] [blame] | 192 | module_put(rcdev->owner); |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 193 | return ERR_PTR(-ENOMEM); |
| 194 | } |
| 195 | |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 196 | rstc->rcdev = rcdev; |
| 197 | rstc->id = rstc_id; |
| 198 | |
| 199 | return rstc; |
| 200 | } |
Vince Hsu | c0a13aa | 2015-07-13 13:39:39 +0100 | [diff] [blame] | 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 | |
Alban Bedel | 3d81216 | 2015-09-01 17:28:31 +0200 | [diff] [blame] | 217 | if (id) { |
Vince Hsu | c0a13aa | 2015-07-13 13:39:39 +0100 | [diff] [blame] | 218 | index = of_property_match_string(node, |
| 219 | "reset-names", id); |
Alban Bedel | 3d81216 | 2015-09-01 17:28:31 +0200 | [diff] [blame] | 220 | if (index < 0) |
| 221 | return ERR_PTR(-ENOENT); |
| 222 | } |
Vince Hsu | c0a13aa | 2015-07-13 13:39:39 +0100 | [diff] [blame] | 223 | return of_reset_control_get_by_index(node, index); |
| 224 | } |
Maxime Ripard | fc0a592 | 2013-12-20 22:41:07 +0100 | [diff] [blame] | 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 | { |
Maxime Ripard | fc0a592 | 2013-12-20 22:41:07 +0100 | [diff] [blame] | 238 | if (!dev) |
| 239 | return ERR_PTR(-EINVAL); |
| 240 | |
Philipp Zabel | b354f68 | 2015-11-18 14:36:35 +0100 | [diff] [blame] | 241 | return of_reset_control_get(dev->of_node, id); |
Maxime Ripard | fc0a592 | 2013-12-20 22:41:07 +0100 | [diff] [blame] | 242 | } |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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 | |
Philipp Zabel | 61fc413 | 2012-11-19 17:23:13 +0100 | [diff] [blame] | 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); |