Peter Rosin | 0edff03 | 2017-12-29 00:22:55 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 2 | /* |
| 3 | * Multiplexer subsystem |
| 4 | * |
| 5 | * Copyright (C) 2017 Axentia Technologies AB |
| 6 | * |
| 7 | * Author: Peter Rosin <peda@axentia.se> |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 8 | */ |
| 9 | |
| 10 | #define pr_fmt(fmt) "mux-core: " fmt |
| 11 | |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 12 | #include <linux/delay.h> |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 13 | #include <linux/device.h> |
| 14 | #include <linux/err.h> |
| 15 | #include <linux/export.h> |
| 16 | #include <linux/idr.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/mux/consumer.h> |
| 20 | #include <linux/mux/driver.h> |
| 21 | #include <linux/of.h> |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 22 | #include <linux/slab.h> |
| 23 | |
| 24 | /* |
| 25 | * The idle-as-is "state" is not an actual state that may be selected, it |
| 26 | * only implies that the state should not be changed. So, use that state |
| 27 | * as indication that the cached state of the multiplexer is unknown. |
| 28 | */ |
| 29 | #define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS |
| 30 | |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 31 | /** |
| 32 | * struct mux_state - Represents a mux controller state specific to a given |
| 33 | * consumer. |
| 34 | * @mux: Pointer to a mux controller. |
Yang Li | ad10ab1 | 2022-01-07 08:44:45 +0100 | [diff] [blame] | 35 | * @state: State of the mux to be selected. |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 36 | * |
| 37 | * This structure is specific to the consumer that acquires it and has |
| 38 | * information specific to that consumer. |
| 39 | */ |
| 40 | struct mux_state { |
| 41 | struct mux_control *mux; |
| 42 | unsigned int state; |
| 43 | }; |
| 44 | |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 45 | static struct class mux_class = { |
| 46 | .name = "mux", |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 47 | }; |
| 48 | |
| 49 | static DEFINE_IDA(mux_ida); |
| 50 | |
| 51 | static int __init mux_init(void) |
| 52 | { |
| 53 | ida_init(&mux_ida); |
| 54 | return class_register(&mux_class); |
| 55 | } |
| 56 | |
| 57 | static void __exit mux_exit(void) |
| 58 | { |
Kuppuswamy Sathyanarayanan | 9988499 | 2017-07-10 14:45:34 +0200 | [diff] [blame] | 59 | class_unregister(&mux_class); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 60 | ida_destroy(&mux_ida); |
| 61 | } |
| 62 | |
| 63 | static void mux_chip_release(struct device *dev) |
| 64 | { |
| 65 | struct mux_chip *mux_chip = to_mux_chip(dev); |
| 66 | |
| 67 | ida_simple_remove(&mux_ida, mux_chip->id); |
| 68 | kfree(mux_chip); |
| 69 | } |
| 70 | |
Bhumika Goyal | a49c3fe | 2017-08-29 10:49:52 +0200 | [diff] [blame] | 71 | static const struct device_type mux_type = { |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 72 | .name = "mux-chip", |
| 73 | .release = mux_chip_release, |
| 74 | }; |
| 75 | |
| 76 | /** |
| 77 | * mux_chip_alloc() - Allocate a mux-chip. |
| 78 | * @dev: The parent device implementing the mux interface. |
| 79 | * @controllers: The number of mux controllers to allocate for this chip. |
| 80 | * @sizeof_priv: Size of extra memory area for private use by the caller. |
| 81 | * |
| 82 | * After allocating the mux-chip with the desired number of mux controllers |
| 83 | * but before registering the chip, the mux driver is required to configure |
| 84 | * the number of valid mux states in the mux_chip->mux[N].states members and |
| 85 | * the desired idle state in the returned mux_chip->mux[N].idle_state members. |
| 86 | * The default idle state is MUX_IDLE_AS_IS. The mux driver also needs to |
| 87 | * provide a pointer to the operations struct in the mux_chip->ops member |
| 88 | * before registering the mux-chip with mux_chip_register. |
| 89 | * |
| 90 | * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno. |
| 91 | */ |
| 92 | struct mux_chip *mux_chip_alloc(struct device *dev, |
| 93 | unsigned int controllers, size_t sizeof_priv) |
| 94 | { |
| 95 | struct mux_chip *mux_chip; |
| 96 | int i; |
| 97 | |
| 98 | if (WARN_ON(!dev || !controllers)) |
| 99 | return ERR_PTR(-EINVAL); |
| 100 | |
| 101 | mux_chip = kzalloc(sizeof(*mux_chip) + |
| 102 | controllers * sizeof(*mux_chip->mux) + |
| 103 | sizeof_priv, GFP_KERNEL); |
| 104 | if (!mux_chip) |
| 105 | return ERR_PTR(-ENOMEM); |
| 106 | |
| 107 | mux_chip->mux = (struct mux_control *)(mux_chip + 1); |
| 108 | mux_chip->dev.class = &mux_class; |
| 109 | mux_chip->dev.type = &mux_type; |
| 110 | mux_chip->dev.parent = dev; |
| 111 | mux_chip->dev.of_node = dev->of_node; |
| 112 | dev_set_drvdata(&mux_chip->dev, mux_chip); |
| 113 | |
| 114 | mux_chip->id = ida_simple_get(&mux_ida, 0, 0, GFP_KERNEL); |
| 115 | if (mux_chip->id < 0) { |
| 116 | int err = mux_chip->id; |
| 117 | |
| 118 | pr_err("muxchipX failed to get a device id\n"); |
| 119 | kfree(mux_chip); |
| 120 | return ERR_PTR(err); |
| 121 | } |
| 122 | dev_set_name(&mux_chip->dev, "muxchip%d", mux_chip->id); |
| 123 | |
| 124 | mux_chip->controllers = controllers; |
| 125 | for (i = 0; i < controllers; ++i) { |
| 126 | struct mux_control *mux = &mux_chip->mux[i]; |
| 127 | |
| 128 | mux->chip = mux_chip; |
| 129 | sema_init(&mux->lock, 1); |
| 130 | mux->cached_state = MUX_CACHE_UNKNOWN; |
| 131 | mux->idle_state = MUX_IDLE_AS_IS; |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 132 | mux->last_change = ktime_get(); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 133 | } |
| 134 | |
| 135 | device_initialize(&mux_chip->dev); |
| 136 | |
| 137 | return mux_chip; |
| 138 | } |
| 139 | EXPORT_SYMBOL_GPL(mux_chip_alloc); |
| 140 | |
| 141 | static int mux_control_set(struct mux_control *mux, int state) |
| 142 | { |
| 143 | int ret = mux->chip->ops->set(mux, state); |
| 144 | |
| 145 | mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state; |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 146 | if (ret >= 0) |
| 147 | mux->last_change = ktime_get(); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 148 | |
| 149 | return ret; |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * mux_chip_register() - Register a mux-chip, thus readying the controllers |
| 154 | * for use. |
| 155 | * @mux_chip: The mux-chip to register. |
| 156 | * |
| 157 | * Do not retry registration of the same mux-chip on failure. You should |
| 158 | * instead put it away with mux_chip_free() and allocate a new one, if you |
| 159 | * for some reason would like to retry registration. |
| 160 | * |
| 161 | * Return: Zero on success or a negative errno on error. |
| 162 | */ |
| 163 | int mux_chip_register(struct mux_chip *mux_chip) |
| 164 | { |
| 165 | int i; |
| 166 | int ret; |
| 167 | |
| 168 | for (i = 0; i < mux_chip->controllers; ++i) { |
| 169 | struct mux_control *mux = &mux_chip->mux[i]; |
| 170 | |
| 171 | if (mux->idle_state == mux->cached_state) |
| 172 | continue; |
| 173 | |
| 174 | ret = mux_control_set(mux, mux->idle_state); |
| 175 | if (ret < 0) { |
| 176 | dev_err(&mux_chip->dev, "unable to set idle state\n"); |
| 177 | return ret; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | ret = device_add(&mux_chip->dev); |
| 182 | if (ret < 0) |
| 183 | dev_err(&mux_chip->dev, |
| 184 | "device_add failed in %s: %d\n", __func__, ret); |
| 185 | return ret; |
| 186 | } |
| 187 | EXPORT_SYMBOL_GPL(mux_chip_register); |
| 188 | |
| 189 | /** |
| 190 | * mux_chip_unregister() - Take the mux-chip off-line. |
| 191 | * @mux_chip: The mux-chip to unregister. |
| 192 | * |
| 193 | * mux_chip_unregister() reverses the effects of mux_chip_register(). |
| 194 | * But not completely, you should not try to call mux_chip_register() |
| 195 | * on a mux-chip that has been registered before. |
| 196 | */ |
| 197 | void mux_chip_unregister(struct mux_chip *mux_chip) |
| 198 | { |
| 199 | device_del(&mux_chip->dev); |
| 200 | } |
| 201 | EXPORT_SYMBOL_GPL(mux_chip_unregister); |
| 202 | |
| 203 | /** |
| 204 | * mux_chip_free() - Free the mux-chip for good. |
| 205 | * @mux_chip: The mux-chip to free. |
| 206 | * |
| 207 | * mux_chip_free() reverses the effects of mux_chip_alloc(). |
| 208 | */ |
| 209 | void mux_chip_free(struct mux_chip *mux_chip) |
| 210 | { |
| 211 | if (!mux_chip) |
| 212 | return; |
| 213 | |
| 214 | put_device(&mux_chip->dev); |
| 215 | } |
| 216 | EXPORT_SYMBOL_GPL(mux_chip_free); |
| 217 | |
| 218 | static void devm_mux_chip_release(struct device *dev, void *res) |
| 219 | { |
| 220 | struct mux_chip *mux_chip = *(struct mux_chip **)res; |
| 221 | |
| 222 | mux_chip_free(mux_chip); |
| 223 | } |
| 224 | |
| 225 | /** |
| 226 | * devm_mux_chip_alloc() - Resource-managed version of mux_chip_alloc(). |
| 227 | * @dev: The parent device implementing the mux interface. |
| 228 | * @controllers: The number of mux controllers to allocate for this chip. |
| 229 | * @sizeof_priv: Size of extra memory area for private use by the caller. |
| 230 | * |
| 231 | * See mux_chip_alloc() for more details. |
| 232 | * |
| 233 | * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno. |
| 234 | */ |
| 235 | struct mux_chip *devm_mux_chip_alloc(struct device *dev, |
| 236 | unsigned int controllers, |
| 237 | size_t sizeof_priv) |
| 238 | { |
| 239 | struct mux_chip **ptr, *mux_chip; |
| 240 | |
| 241 | ptr = devres_alloc(devm_mux_chip_release, sizeof(*ptr), GFP_KERNEL); |
| 242 | if (!ptr) |
| 243 | return ERR_PTR(-ENOMEM); |
| 244 | |
| 245 | mux_chip = mux_chip_alloc(dev, controllers, sizeof_priv); |
| 246 | if (IS_ERR(mux_chip)) { |
| 247 | devres_free(ptr); |
| 248 | return mux_chip; |
| 249 | } |
| 250 | |
| 251 | *ptr = mux_chip; |
| 252 | devres_add(dev, ptr); |
| 253 | |
| 254 | return mux_chip; |
| 255 | } |
| 256 | EXPORT_SYMBOL_GPL(devm_mux_chip_alloc); |
| 257 | |
| 258 | static void devm_mux_chip_reg_release(struct device *dev, void *res) |
| 259 | { |
| 260 | struct mux_chip *mux_chip = *(struct mux_chip **)res; |
| 261 | |
| 262 | mux_chip_unregister(mux_chip); |
| 263 | } |
| 264 | |
| 265 | /** |
| 266 | * devm_mux_chip_register() - Resource-managed version mux_chip_register(). |
| 267 | * @dev: The parent device implementing the mux interface. |
| 268 | * @mux_chip: The mux-chip to register. |
| 269 | * |
| 270 | * See mux_chip_register() for more details. |
| 271 | * |
| 272 | * Return: Zero on success or a negative errno on error. |
| 273 | */ |
| 274 | int devm_mux_chip_register(struct device *dev, |
| 275 | struct mux_chip *mux_chip) |
| 276 | { |
| 277 | struct mux_chip **ptr; |
| 278 | int res; |
| 279 | |
| 280 | ptr = devres_alloc(devm_mux_chip_reg_release, sizeof(*ptr), GFP_KERNEL); |
| 281 | if (!ptr) |
| 282 | return -ENOMEM; |
| 283 | |
| 284 | res = mux_chip_register(mux_chip); |
| 285 | if (res) { |
| 286 | devres_free(ptr); |
| 287 | return res; |
| 288 | } |
| 289 | |
| 290 | *ptr = mux_chip; |
| 291 | devres_add(dev, ptr); |
| 292 | |
| 293 | return res; |
| 294 | } |
| 295 | EXPORT_SYMBOL_GPL(devm_mux_chip_register); |
| 296 | |
| 297 | /** |
| 298 | * mux_control_states() - Query the number of multiplexer states. |
| 299 | * @mux: The mux-control to query. |
| 300 | * |
| 301 | * Return: The number of multiplexer states. |
| 302 | */ |
| 303 | unsigned int mux_control_states(struct mux_control *mux) |
| 304 | { |
| 305 | return mux->states; |
| 306 | } |
| 307 | EXPORT_SYMBOL_GPL(mux_control_states); |
| 308 | |
| 309 | /* |
| 310 | * The mux->lock must be down when calling this function. |
| 311 | */ |
| 312 | static int __mux_control_select(struct mux_control *mux, int state) |
| 313 | { |
| 314 | int ret; |
| 315 | |
| 316 | if (WARN_ON(state < 0 || state >= mux->states)) |
| 317 | return -EINVAL; |
| 318 | |
| 319 | if (mux->cached_state == state) |
| 320 | return 0; |
| 321 | |
| 322 | ret = mux_control_set(mux, state); |
| 323 | if (ret >= 0) |
| 324 | return 0; |
| 325 | |
| 326 | /* The mux update failed, try to revert if appropriate... */ |
| 327 | if (mux->idle_state != MUX_IDLE_AS_IS) |
| 328 | mux_control_set(mux, mux->idle_state); |
| 329 | |
| 330 | return ret; |
| 331 | } |
| 332 | |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 333 | static void mux_control_delay(struct mux_control *mux, unsigned int delay_us) |
| 334 | { |
| 335 | ktime_t delayend; |
| 336 | s64 remaining; |
| 337 | |
| 338 | if (!delay_us) |
| 339 | return; |
| 340 | |
| 341 | delayend = ktime_add_us(mux->last_change, delay_us); |
| 342 | remaining = ktime_us_delta(delayend, ktime_get()); |
| 343 | if (remaining > 0) |
| 344 | fsleep(remaining); |
| 345 | } |
| 346 | |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 347 | /** |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 348 | * mux_control_select_delay() - Select the given multiplexer state. |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 349 | * @mux: The mux-control to request a change of state from. |
| 350 | * @state: The new requested state. |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 351 | * @delay_us: The time to delay (in microseconds) if the mux state is changed. |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 352 | * |
| 353 | * On successfully selecting the mux-control state, it will be locked until |
| 354 | * there is a call to mux_control_deselect(). If the mux-control is already |
| 355 | * selected when mux_control_select() is called, the caller will be blocked |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 356 | * until mux_control_deselect() or mux_state_deselect() is called (by someone |
| 357 | * else). |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 358 | * |
| 359 | * Therefore, make sure to call mux_control_deselect() when the operation is |
| 360 | * complete and the mux-control is free for others to use, but do not call |
| 361 | * mux_control_deselect() if mux_control_select() fails. |
| 362 | * |
| 363 | * Return: 0 when the mux-control state has the requested state or a negative |
| 364 | * errno on error. |
| 365 | */ |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 366 | int mux_control_select_delay(struct mux_control *mux, unsigned int state, |
| 367 | unsigned int delay_us) |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 368 | { |
| 369 | int ret; |
| 370 | |
| 371 | ret = down_killable(&mux->lock); |
| 372 | if (ret < 0) |
| 373 | return ret; |
| 374 | |
| 375 | ret = __mux_control_select(mux, state); |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 376 | if (ret >= 0) |
| 377 | mux_control_delay(mux, delay_us); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 378 | |
| 379 | if (ret < 0) |
| 380 | up(&mux->lock); |
| 381 | |
| 382 | return ret; |
| 383 | } |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 384 | EXPORT_SYMBOL_GPL(mux_control_select_delay); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 385 | |
| 386 | /** |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 387 | * mux_state_select_delay() - Select the given multiplexer state. |
| 388 | * @mstate: The mux-state to select. |
| 389 | * @delay_us: The time to delay (in microseconds) if the mux state is changed. |
| 390 | * |
| 391 | * On successfully selecting the mux-state, its mux-control will be locked |
| 392 | * until there is a call to mux_state_deselect(). If the mux-control is already |
| 393 | * selected when mux_state_select() is called, the caller will be blocked |
| 394 | * until mux_state_deselect() or mux_control_deselect() is called (by someone |
| 395 | * else). |
| 396 | * |
| 397 | * Therefore, make sure to call mux_state_deselect() when the operation is |
| 398 | * complete and the mux-control is free for others to use, but do not call |
| 399 | * mux_state_deselect() if mux_state_select() fails. |
| 400 | * |
| 401 | * Return: 0 when the mux-state has been selected or a negative |
| 402 | * errno on error. |
| 403 | */ |
| 404 | int mux_state_select_delay(struct mux_state *mstate, unsigned int delay_us) |
| 405 | { |
| 406 | return mux_control_select_delay(mstate->mux, mstate->state, delay_us); |
| 407 | } |
| 408 | EXPORT_SYMBOL_GPL(mux_state_select_delay); |
| 409 | |
| 410 | /** |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 411 | * mux_control_try_select_delay() - Try to select the given multiplexer state. |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 412 | * @mux: The mux-control to request a change of state from. |
| 413 | * @state: The new requested state. |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 414 | * @delay_us: The time to delay (in microseconds) if the mux state is changed. |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 415 | * |
| 416 | * On successfully selecting the mux-control state, it will be locked until |
Peter Rosin | f22d111 | 2022-01-07 08:44:38 +0100 | [diff] [blame] | 417 | * mux_control_deselect() is called. |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 418 | * |
| 419 | * Therefore, make sure to call mux_control_deselect() when the operation is |
| 420 | * complete and the mux-control is free for others to use, but do not call |
| 421 | * mux_control_deselect() if mux_control_try_select() fails. |
| 422 | * |
| 423 | * Return: 0 when the mux-control state has the requested state or a negative |
| 424 | * errno on error. Specifically -EBUSY if the mux-control is contended. |
| 425 | */ |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 426 | int mux_control_try_select_delay(struct mux_control *mux, unsigned int state, |
| 427 | unsigned int delay_us) |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 428 | { |
| 429 | int ret; |
| 430 | |
| 431 | if (down_trylock(&mux->lock)) |
| 432 | return -EBUSY; |
| 433 | |
| 434 | ret = __mux_control_select(mux, state); |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 435 | if (ret >= 0) |
| 436 | mux_control_delay(mux, delay_us); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 437 | |
| 438 | if (ret < 0) |
| 439 | up(&mux->lock); |
| 440 | |
| 441 | return ret; |
| 442 | } |
Vincent Whitchurch | 17b5b57 | 2021-10-07 15:46:39 +0200 | [diff] [blame] | 443 | EXPORT_SYMBOL_GPL(mux_control_try_select_delay); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 444 | |
| 445 | /** |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 446 | * mux_state_try_select_delay() - Try to select the given multiplexer state. |
| 447 | * @mstate: The mux-state to select. |
| 448 | * @delay_us: The time to delay (in microseconds) if the mux state is changed. |
| 449 | * |
| 450 | * On successfully selecting the mux-state, its mux-control will be locked |
| 451 | * until mux_state_deselect() is called. |
| 452 | * |
| 453 | * Therefore, make sure to call mux_state_deselect() when the operation is |
| 454 | * complete and the mux-control is free for others to use, but do not call |
| 455 | * mux_state_deselect() if mux_state_try_select() fails. |
| 456 | * |
| 457 | * Return: 0 when the mux-state has been selected or a negative errno on |
| 458 | * error. Specifically -EBUSY if the mux-control is contended. |
| 459 | */ |
| 460 | int mux_state_try_select_delay(struct mux_state *mstate, unsigned int delay_us) |
| 461 | { |
| 462 | return mux_control_try_select_delay(mstate->mux, mstate->state, delay_us); |
| 463 | } |
| 464 | EXPORT_SYMBOL_GPL(mux_state_try_select_delay); |
| 465 | |
| 466 | /** |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 467 | * mux_control_deselect() - Deselect the previously selected multiplexer state. |
| 468 | * @mux: The mux-control to deselect. |
| 469 | * |
| 470 | * It is required that a single call is made to mux_control_deselect() for |
| 471 | * each and every successful call made to either of mux_control_select() or |
| 472 | * mux_control_try_select(). |
| 473 | * |
| 474 | * Return: 0 on success and a negative errno on error. An error can only |
| 475 | * occur if the mux has an idle state. Note that even if an error occurs, the |
| 476 | * mux-control is unlocked and is thus free for the next access. |
| 477 | */ |
| 478 | int mux_control_deselect(struct mux_control *mux) |
| 479 | { |
| 480 | int ret = 0; |
| 481 | |
| 482 | if (mux->idle_state != MUX_IDLE_AS_IS && |
| 483 | mux->idle_state != mux->cached_state) |
| 484 | ret = mux_control_set(mux, mux->idle_state); |
| 485 | |
| 486 | up(&mux->lock); |
| 487 | |
| 488 | return ret; |
| 489 | } |
| 490 | EXPORT_SYMBOL_GPL(mux_control_deselect); |
| 491 | |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 492 | /** |
| 493 | * mux_state_deselect() - Deselect the previously selected multiplexer state. |
| 494 | * @mstate: The mux-state to deselect. |
| 495 | * |
| 496 | * It is required that a single call is made to mux_state_deselect() for |
| 497 | * each and every successful call made to either of mux_state_select() or |
| 498 | * mux_state_try_select(). |
| 499 | * |
| 500 | * Return: 0 on success and a negative errno on error. An error can only |
| 501 | * occur if the mux has an idle state. Note that even if an error occurs, the |
| 502 | * mux-control is unlocked and is thus free for the next access. |
| 503 | */ |
| 504 | int mux_state_deselect(struct mux_state *mstate) |
| 505 | { |
| 506 | return mux_control_deselect(mstate->mux); |
| 507 | } |
| 508 | EXPORT_SYMBOL_GPL(mux_state_deselect); |
| 509 | |
Hans de Goede | aa1f10e | 2017-12-29 00:22:54 +0100 | [diff] [blame] | 510 | /* Note this function returns a reference to the mux_chip dev. */ |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 511 | static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np) |
| 512 | { |
| 513 | struct device *dev; |
| 514 | |
Suzuki K Poulose | cfba5de | 2019-07-23 23:18:33 +0100 | [diff] [blame] | 515 | dev = class_find_device_by_of_node(&mux_class, np); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 516 | |
| 517 | return dev ? to_mux_chip(dev) : NULL; |
| 518 | } |
| 519 | |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 520 | /* |
| 521 | * mux_get() - Get the mux-control for a device. |
| 522 | * @dev: The device that needs a mux-control. |
| 523 | * @mux_name: The name identifying the mux-control. |
| 524 | * @state: Pointer to where the requested state is returned, or NULL when |
| 525 | * the required multiplexer states are handled by other means. |
| 526 | * |
| 527 | * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. |
| 528 | */ |
| 529 | static struct mux_control *mux_get(struct device *dev, const char *mux_name, |
| 530 | unsigned int *state) |
| 531 | { |
| 532 | struct device_node *np = dev->of_node; |
| 533 | struct of_phandle_args args; |
| 534 | struct mux_chip *mux_chip; |
| 535 | unsigned int controller; |
| 536 | int index = 0; |
| 537 | int ret; |
| 538 | |
| 539 | if (mux_name) { |
| 540 | if (state) |
| 541 | index = of_property_match_string(np, "mux-state-names", |
| 542 | mux_name); |
| 543 | else |
| 544 | index = of_property_match_string(np, "mux-control-names", |
| 545 | mux_name); |
| 546 | if (index < 0) { |
| 547 | dev_err(dev, "mux controller '%s' not found\n", |
| 548 | mux_name); |
| 549 | return ERR_PTR(index); |
| 550 | } |
| 551 | } |
| 552 | |
| 553 | if (state) |
| 554 | ret = of_parse_phandle_with_args(np, |
| 555 | "mux-states", "#mux-state-cells", |
| 556 | index, &args); |
| 557 | else |
| 558 | ret = of_parse_phandle_with_args(np, |
| 559 | "mux-controls", "#mux-control-cells", |
| 560 | index, &args); |
| 561 | if (ret) { |
| 562 | dev_err(dev, "%pOF: failed to get mux-%s %s(%i)\n", |
| 563 | np, state ? "state" : "control", mux_name ?: "", index); |
| 564 | return ERR_PTR(ret); |
| 565 | } |
| 566 | |
| 567 | mux_chip = of_find_mux_chip_by_node(args.np); |
| 568 | of_node_put(args.np); |
| 569 | if (!mux_chip) |
| 570 | return ERR_PTR(-EPROBE_DEFER); |
| 571 | |
| 572 | controller = 0; |
| 573 | if (state) { |
| 574 | if (args.args_count > 2 || args.args_count == 0 || |
| 575 | (args.args_count < 2 && mux_chip->controllers > 1)) { |
| 576 | dev_err(dev, "%pOF: wrong #mux-state-cells for %pOF\n", |
| 577 | np, args.np); |
| 578 | put_device(&mux_chip->dev); |
| 579 | return ERR_PTR(-EINVAL); |
| 580 | } |
| 581 | |
| 582 | if (args.args_count == 2) { |
| 583 | controller = args.args[0]; |
| 584 | *state = args.args[1]; |
| 585 | } else { |
| 586 | *state = args.args[0]; |
| 587 | } |
| 588 | |
| 589 | } else { |
| 590 | if (args.args_count > 1 || |
| 591 | (!args.args_count && mux_chip->controllers > 1)) { |
| 592 | dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n", |
| 593 | np, args.np); |
| 594 | put_device(&mux_chip->dev); |
| 595 | return ERR_PTR(-EINVAL); |
| 596 | } |
| 597 | |
| 598 | if (args.args_count) |
| 599 | controller = args.args[0]; |
| 600 | } |
| 601 | |
| 602 | if (controller >= mux_chip->controllers) { |
| 603 | dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n", |
| 604 | np, controller, args.np); |
| 605 | put_device(&mux_chip->dev); |
| 606 | return ERR_PTR(-EINVAL); |
| 607 | } |
| 608 | |
| 609 | return &mux_chip->mux[controller]; |
| 610 | } |
| 611 | |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 612 | /** |
| 613 | * mux_control_get() - Get the mux-control for a device. |
| 614 | * @dev: The device that needs a mux-control. |
| 615 | * @mux_name: The name identifying the mux-control. |
| 616 | * |
| 617 | * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. |
| 618 | */ |
| 619 | struct mux_control *mux_control_get(struct device *dev, const char *mux_name) |
| 620 | { |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 621 | return mux_get(dev, mux_name, NULL); |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 622 | } |
| 623 | EXPORT_SYMBOL_GPL(mux_control_get); |
| 624 | |
| 625 | /** |
| 626 | * mux_control_put() - Put away the mux-control for good. |
| 627 | * @mux: The mux-control to put away. |
| 628 | * |
| 629 | * mux_control_put() reverses the effects of mux_control_get(). |
| 630 | */ |
| 631 | void mux_control_put(struct mux_control *mux) |
| 632 | { |
| 633 | put_device(&mux->chip->dev); |
| 634 | } |
| 635 | EXPORT_SYMBOL_GPL(mux_control_put); |
| 636 | |
| 637 | static void devm_mux_control_release(struct device *dev, void *res) |
| 638 | { |
| 639 | struct mux_control *mux = *(struct mux_control **)res; |
| 640 | |
| 641 | mux_control_put(mux); |
| 642 | } |
| 643 | |
| 644 | /** |
| 645 | * devm_mux_control_get() - Get the mux-control for a device, with resource |
| 646 | * management. |
| 647 | * @dev: The device that needs a mux-control. |
| 648 | * @mux_name: The name identifying the mux-control. |
| 649 | * |
| 650 | * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. |
| 651 | */ |
| 652 | struct mux_control *devm_mux_control_get(struct device *dev, |
| 653 | const char *mux_name) |
| 654 | { |
| 655 | struct mux_control **ptr, *mux; |
| 656 | |
| 657 | ptr = devres_alloc(devm_mux_control_release, sizeof(*ptr), GFP_KERNEL); |
| 658 | if (!ptr) |
| 659 | return ERR_PTR(-ENOMEM); |
| 660 | |
| 661 | mux = mux_control_get(dev, mux_name); |
| 662 | if (IS_ERR(mux)) { |
| 663 | devres_free(ptr); |
| 664 | return mux; |
| 665 | } |
| 666 | |
| 667 | *ptr = mux; |
| 668 | devres_add(dev, ptr); |
| 669 | |
| 670 | return mux; |
| 671 | } |
| 672 | EXPORT_SYMBOL_GPL(devm_mux_control_get); |
| 673 | |
| 674 | /* |
Peter Rosin | 6632866 | 2022-01-07 08:44:32 +0100 | [diff] [blame] | 675 | * mux_state_get() - Get the mux-state for a device. |
| 676 | * @dev: The device that needs a mux-state. |
| 677 | * @mux_name: The name identifying the mux-state. |
| 678 | * |
| 679 | * Return: A pointer to the mux-state, or an ERR_PTR with a negative errno. |
| 680 | */ |
| 681 | static struct mux_state *mux_state_get(struct device *dev, const char *mux_name) |
| 682 | { |
| 683 | struct mux_state *mstate; |
| 684 | |
| 685 | mstate = kzalloc(sizeof(*mstate), GFP_KERNEL); |
| 686 | if (!mstate) |
| 687 | return ERR_PTR(-ENOMEM); |
| 688 | |
| 689 | mstate->mux = mux_get(dev, mux_name, &mstate->state); |
| 690 | if (IS_ERR(mstate->mux)) { |
| 691 | int err = PTR_ERR(mstate->mux); |
| 692 | |
| 693 | kfree(mstate); |
| 694 | return ERR_PTR(err); |
| 695 | } |
| 696 | |
| 697 | return mstate; |
| 698 | } |
| 699 | |
| 700 | /* |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 701 | * mux_state_put() - Put away the mux-state for good. |
| 702 | * @mstate: The mux-state to put away. |
| 703 | * |
| 704 | * mux_state_put() reverses the effects of mux_state_get(). |
| 705 | */ |
| 706 | static void mux_state_put(struct mux_state *mstate) |
| 707 | { |
| 708 | mux_control_put(mstate->mux); |
| 709 | kfree(mstate); |
| 710 | } |
| 711 | |
| 712 | static void devm_mux_state_release(struct device *dev, void *res) |
| 713 | { |
| 714 | struct mux_state *mstate = *(struct mux_state **)res; |
| 715 | |
| 716 | mux_state_put(mstate); |
| 717 | } |
| 718 | |
| 719 | /** |
| 720 | * devm_mux_state_get() - Get the mux-state for a device, with resource |
| 721 | * management. |
| 722 | * @dev: The device that needs a mux-control. |
| 723 | * @mux_name: The name identifying the mux-control. |
| 724 | * |
| 725 | * Return: Pointer to the mux-state, or an ERR_PTR with a negative errno. |
| 726 | */ |
| 727 | struct mux_state *devm_mux_state_get(struct device *dev, |
| 728 | const char *mux_name) |
| 729 | { |
| 730 | struct mux_state **ptr, *mstate; |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 731 | |
| 732 | ptr = devres_alloc(devm_mux_state_release, sizeof(*ptr), GFP_KERNEL); |
| 733 | if (!ptr) |
| 734 | return ERR_PTR(-ENOMEM); |
| 735 | |
Peter Rosin | 6632866 | 2022-01-07 08:44:32 +0100 | [diff] [blame] | 736 | mstate = mux_state_get(dev, mux_name); |
| 737 | if (IS_ERR(mstate)) { |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 738 | devres_free(ptr); |
Peter Rosin | 6632866 | 2022-01-07 08:44:32 +0100 | [diff] [blame] | 739 | return mstate; |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 740 | } |
| 741 | |
Aswath Govindraju | 8456448 | 2022-01-07 08:44:25 +0100 | [diff] [blame] | 742 | *ptr = mstate; |
| 743 | devres_add(dev, ptr); |
| 744 | |
| 745 | return mstate; |
| 746 | } |
| 747 | EXPORT_SYMBOL_GPL(devm_mux_state_get); |
| 748 | |
| 749 | /* |
Peter Rosin | a3b02a9 | 2017-05-14 21:51:06 +0200 | [diff] [blame] | 750 | * Using subsys_initcall instead of module_init here to try to ensure - for |
| 751 | * the non-modular case - that the subsystem is initialized when mux consumers |
| 752 | * and mux controllers start to use it. |
| 753 | * For the modular case, the ordering is ensured with module dependencies. |
| 754 | */ |
| 755 | subsys_initcall(mux_init); |
| 756 | module_exit(mux_exit); |
| 757 | |
| 758 | MODULE_DESCRIPTION("Multiplexer subsystem"); |
| 759 | MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); |
| 760 | MODULE_LICENSE("GPL v2"); |