Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Generic pwmlib implementation |
| 3 | * |
| 4 | * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de> |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 5 | * Copyright (C) 2011-2012 Avionic Design GmbH |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2, or (at your option) |
| 10 | * any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; see the file COPYING. If not, write to |
| 19 | * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| 20 | */ |
| 21 | |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/pwm.h> |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 24 | #include <linux/radix-tree.h> |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 25 | #include <linux/list.h> |
| 26 | #include <linux/mutex.h> |
| 27 | #include <linux/err.h> |
| 28 | #include <linux/slab.h> |
| 29 | #include <linux/device.h> |
Thierry Reding | 62099ab | 2012-03-26 09:31:48 +0200 | [diff] [blame^] | 30 | #include <linux/debugfs.h> |
| 31 | #include <linux/seq_file.h> |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 32 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 33 | #define MAX_PWMS 1024 |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 34 | |
| 35 | static DEFINE_MUTEX(pwm_lock); |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 36 | static LIST_HEAD(pwm_chips); |
| 37 | static DECLARE_BITMAP(allocated_pwms, MAX_PWMS); |
| 38 | static RADIX_TREE(pwm_tree, GFP_KERNEL); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 39 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 40 | static struct pwm_device *pwm_to_device(unsigned int pwm) |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 41 | { |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 42 | return radix_tree_lookup(&pwm_tree, pwm); |
| 43 | } |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 44 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 45 | static int alloc_pwms(int pwm, unsigned int count) |
| 46 | { |
| 47 | unsigned int from = 0; |
| 48 | unsigned int start; |
| 49 | |
| 50 | if (pwm >= MAX_PWMS) |
| 51 | return -EINVAL; |
| 52 | |
| 53 | if (pwm >= 0) |
| 54 | from = pwm; |
| 55 | |
| 56 | start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from, |
| 57 | count, 0); |
| 58 | |
| 59 | if (pwm >= 0 && start != pwm) |
| 60 | return -EEXIST; |
| 61 | |
| 62 | if (start + count > MAX_PWMS) |
| 63 | return -ENOSPC; |
| 64 | |
| 65 | return start; |
| 66 | } |
| 67 | |
| 68 | static void free_pwms(struct pwm_chip *chip) |
| 69 | { |
| 70 | unsigned int i; |
| 71 | |
| 72 | for (i = 0; i < chip->npwm; i++) { |
| 73 | struct pwm_device *pwm = &chip->pwms[i]; |
| 74 | radix_tree_delete(&pwm_tree, pwm->pwm); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 75 | } |
| 76 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 77 | bitmap_clear(allocated_pwms, chip->base, chip->npwm); |
| 78 | |
| 79 | kfree(chip->pwms); |
| 80 | chip->pwms = NULL; |
| 81 | } |
| 82 | |
| 83 | static int pwm_device_request(struct pwm_device *pwm, const char *label) |
| 84 | { |
| 85 | int err; |
| 86 | |
| 87 | if (test_bit(PWMF_REQUESTED, &pwm->flags)) |
| 88 | return -EBUSY; |
| 89 | |
| 90 | if (!try_module_get(pwm->chip->ops->owner)) |
| 91 | return -ENODEV; |
| 92 | |
| 93 | if (pwm->chip->ops->request) { |
| 94 | err = pwm->chip->ops->request(pwm->chip, pwm); |
| 95 | if (err) { |
| 96 | module_put(pwm->chip->ops->owner); |
| 97 | return err; |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | set_bit(PWMF_REQUESTED, &pwm->flags); |
| 102 | pwm->label = label; |
| 103 | |
| 104 | return 0; |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * pwm_set_chip_data() - set private chip data for a PWM |
| 109 | * @pwm: PWM device |
| 110 | * @data: pointer to chip-specific data |
| 111 | */ |
| 112 | int pwm_set_chip_data(struct pwm_device *pwm, void *data) |
| 113 | { |
| 114 | if (!pwm) |
| 115 | return -EINVAL; |
| 116 | |
| 117 | pwm->chip_data = data; |
| 118 | |
| 119 | return 0; |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * pwm_get_chip_data() - get private chip data for a PWM |
| 124 | * @pwm: PWM device |
| 125 | */ |
| 126 | void *pwm_get_chip_data(struct pwm_device *pwm) |
| 127 | { |
| 128 | return pwm ? pwm->chip_data : NULL; |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 129 | } |
| 130 | |
| 131 | /** |
| 132 | * pwmchip_add() - register a new PWM chip |
| 133 | * @chip: the PWM chip to add |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 134 | * |
| 135 | * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base |
| 136 | * will be used. |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 137 | */ |
| 138 | int pwmchip_add(struct pwm_chip *chip) |
| 139 | { |
| 140 | struct pwm_device *pwm; |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 141 | unsigned int i; |
| 142 | int ret; |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 143 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 144 | if (!chip || !chip->dev || !chip->ops || !chip->ops->config || |
| 145 | !chip->ops->enable || !chip->ops->disable) |
| 146 | return -EINVAL; |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 147 | |
| 148 | mutex_lock(&pwm_lock); |
| 149 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 150 | ret = alloc_pwms(chip->base, chip->npwm); |
| 151 | if (ret < 0) |
| 152 | goto out; |
| 153 | |
| 154 | chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL); |
| 155 | if (!chip->pwms) { |
| 156 | ret = -ENOMEM; |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 157 | goto out; |
| 158 | } |
| 159 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 160 | chip->base = ret; |
| 161 | |
| 162 | for (i = 0; i < chip->npwm; i++) { |
| 163 | pwm = &chip->pwms[i]; |
| 164 | |
| 165 | pwm->chip = chip; |
| 166 | pwm->pwm = chip->base + i; |
| 167 | pwm->hwpwm = i; |
| 168 | |
| 169 | radix_tree_insert(&pwm_tree, pwm->pwm, pwm); |
| 170 | } |
| 171 | |
| 172 | bitmap_set(allocated_pwms, chip->base, chip->npwm); |
| 173 | |
| 174 | INIT_LIST_HEAD(&chip->list); |
| 175 | list_add(&chip->list, &pwm_chips); |
| 176 | |
| 177 | ret = 0; |
| 178 | |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 179 | out: |
| 180 | mutex_unlock(&pwm_lock); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 181 | return ret; |
| 182 | } |
| 183 | EXPORT_SYMBOL_GPL(pwmchip_add); |
| 184 | |
| 185 | /** |
| 186 | * pwmchip_remove() - remove a PWM chip |
| 187 | * @chip: the PWM chip to remove |
| 188 | * |
| 189 | * Removes a PWM chip. This function may return busy if the PWM chip provides |
| 190 | * a PWM device that is still requested. |
| 191 | */ |
| 192 | int pwmchip_remove(struct pwm_chip *chip) |
| 193 | { |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 194 | unsigned int i; |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 195 | int ret = 0; |
| 196 | |
| 197 | mutex_lock(&pwm_lock); |
| 198 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 199 | for (i = 0; i < chip->npwm; i++) { |
| 200 | struct pwm_device *pwm = &chip->pwms[i]; |
| 201 | |
| 202 | if (test_bit(PWMF_REQUESTED, &pwm->flags)) { |
| 203 | ret = -EBUSY; |
| 204 | goto out; |
| 205 | } |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 206 | } |
| 207 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 208 | list_del_init(&chip->list); |
| 209 | free_pwms(chip); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 210 | |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 211 | out: |
| 212 | mutex_unlock(&pwm_lock); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 213 | return ret; |
| 214 | } |
| 215 | EXPORT_SYMBOL_GPL(pwmchip_remove); |
| 216 | |
| 217 | /** |
| 218 | * pwm_request() - request a PWM device |
| 219 | * @pwm_id: global PWM device index |
| 220 | * @label: PWM device label |
| 221 | */ |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 222 | struct pwm_device *pwm_request(int pwm, const char *label) |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 223 | { |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 224 | struct pwm_device *dev; |
| 225 | int err; |
| 226 | |
| 227 | if (pwm < 0 || pwm >= MAX_PWMS) |
| 228 | return ERR_PTR(-EINVAL); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 229 | |
| 230 | mutex_lock(&pwm_lock); |
| 231 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 232 | dev = pwm_to_device(pwm); |
| 233 | if (!dev) { |
| 234 | dev = ERR_PTR(-EPROBE_DEFER); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 235 | goto out; |
| 236 | } |
| 237 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 238 | err = pwm_device_request(dev, label); |
| 239 | if (err < 0) |
| 240 | dev = ERR_PTR(err); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 241 | |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 242 | out: |
| 243 | mutex_unlock(&pwm_lock); |
| 244 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 245 | return dev; |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 246 | } |
| 247 | EXPORT_SYMBOL_GPL(pwm_request); |
| 248 | |
| 249 | /** |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 250 | * pwm_request_from_chip() - request a PWM device relative to a PWM chip |
| 251 | * @chip: PWM chip |
| 252 | * @index: per-chip index of the PWM to request |
| 253 | * @label: a literal description string of this PWM |
| 254 | * |
| 255 | * Returns the PWM at the given index of the given PWM chip. A negative error |
| 256 | * code is returned if the index is not valid for the specified PWM chip or |
| 257 | * if the PWM device cannot be requested. |
| 258 | */ |
| 259 | struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
| 260 | unsigned int index, |
| 261 | const char *label) |
| 262 | { |
| 263 | struct pwm_device *pwm; |
| 264 | int err; |
| 265 | |
| 266 | if (!chip || index >= chip->npwm) |
| 267 | return ERR_PTR(-EINVAL); |
| 268 | |
| 269 | mutex_lock(&pwm_lock); |
| 270 | pwm = &chip->pwms[index]; |
| 271 | |
| 272 | err = pwm_device_request(pwm, label); |
| 273 | if (err < 0) |
| 274 | pwm = ERR_PTR(err); |
| 275 | |
| 276 | mutex_unlock(&pwm_lock); |
| 277 | return pwm; |
| 278 | } |
| 279 | EXPORT_SYMBOL_GPL(pwm_request_from_chip); |
| 280 | |
| 281 | /** |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 282 | * pwm_free() - free a PWM device |
| 283 | * @pwm: PWM device |
| 284 | */ |
| 285 | void pwm_free(struct pwm_device *pwm) |
| 286 | { |
| 287 | mutex_lock(&pwm_lock); |
| 288 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 289 | if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) { |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 290 | pr_warning("PWM device already freed\n"); |
| 291 | goto out; |
| 292 | } |
| 293 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 294 | if (pwm->chip->ops->free) |
| 295 | pwm->chip->ops->free(pwm->chip, pwm); |
| 296 | |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 297 | pwm->label = NULL; |
| 298 | |
| 299 | module_put(pwm->chip->ops->owner); |
| 300 | out: |
| 301 | mutex_unlock(&pwm_lock); |
| 302 | } |
| 303 | EXPORT_SYMBOL_GPL(pwm_free); |
| 304 | |
| 305 | /** |
| 306 | * pwm_config() - change a PWM device configuration |
| 307 | * @pwm: PWM device |
| 308 | * @duty_ns: "on" time (in nanoseconds) |
| 309 | * @period_ns: duration (in nanoseconds) of one cycle |
| 310 | */ |
| 311 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) |
| 312 | { |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 313 | if (!pwm || period_ns == 0 || duty_ns > period_ns) |
| 314 | return -EINVAL; |
| 315 | |
| 316 | return pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 317 | } |
| 318 | EXPORT_SYMBOL_GPL(pwm_config); |
| 319 | |
| 320 | /** |
| 321 | * pwm_enable() - start a PWM output toggling |
| 322 | * @pwm: PWM device |
| 323 | */ |
| 324 | int pwm_enable(struct pwm_device *pwm) |
| 325 | { |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 326 | if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags)) |
| 327 | return pwm->chip->ops->enable(pwm->chip, pwm); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 328 | |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 329 | return pwm ? 0 : -EINVAL; |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 330 | } |
| 331 | EXPORT_SYMBOL_GPL(pwm_enable); |
| 332 | |
| 333 | /** |
| 334 | * pwm_disable() - stop a PWM output toggling |
| 335 | * @pwm: PWM device |
| 336 | */ |
| 337 | void pwm_disable(struct pwm_device *pwm) |
| 338 | { |
Thierry Reding | f051c46 | 2011-12-14 11:12:23 +0100 | [diff] [blame] | 339 | if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags)) |
| 340 | pwm->chip->ops->disable(pwm->chip, pwm); |
Sascha Hauer | 0c2498f | 2011-01-28 09:40:40 +0100 | [diff] [blame] | 341 | } |
| 342 | EXPORT_SYMBOL_GPL(pwm_disable); |
Thierry Reding | 62099ab | 2012-03-26 09:31:48 +0200 | [diff] [blame^] | 343 | |
| 344 | #ifdef CONFIG_DEBUG_FS |
| 345 | static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) |
| 346 | { |
| 347 | unsigned int i; |
| 348 | |
| 349 | for (i = 0; i < chip->npwm; i++) { |
| 350 | struct pwm_device *pwm = &chip->pwms[i]; |
| 351 | |
| 352 | seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label); |
| 353 | |
| 354 | if (test_bit(PWMF_REQUESTED, &pwm->flags)) |
| 355 | seq_printf(s, " requested"); |
| 356 | |
| 357 | if (test_bit(PWMF_ENABLED, &pwm->flags)) |
| 358 | seq_printf(s, " enabled"); |
| 359 | |
| 360 | seq_printf(s, "\n"); |
| 361 | } |
| 362 | } |
| 363 | |
| 364 | static void *pwm_seq_start(struct seq_file *s, loff_t *pos) |
| 365 | { |
| 366 | mutex_lock(&pwm_lock); |
| 367 | s->private = ""; |
| 368 | |
| 369 | return seq_list_start(&pwm_chips, *pos); |
| 370 | } |
| 371 | |
| 372 | static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos) |
| 373 | { |
| 374 | s->private = "\n"; |
| 375 | |
| 376 | return seq_list_next(v, &pwm_chips, pos); |
| 377 | } |
| 378 | |
| 379 | static void pwm_seq_stop(struct seq_file *s, void *v) |
| 380 | { |
| 381 | mutex_unlock(&pwm_lock); |
| 382 | } |
| 383 | |
| 384 | static int pwm_seq_show(struct seq_file *s, void *v) |
| 385 | { |
| 386 | struct pwm_chip *chip = list_entry(v, struct pwm_chip, list); |
| 387 | |
| 388 | seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private, |
| 389 | chip->dev->bus ? chip->dev->bus->name : "no-bus", |
| 390 | dev_name(chip->dev), chip->npwm, |
| 391 | (chip->npwm != 1) ? "s" : ""); |
| 392 | |
| 393 | if (chip->ops->dbg_show) |
| 394 | chip->ops->dbg_show(chip, s); |
| 395 | else |
| 396 | pwm_dbg_show(chip, s); |
| 397 | |
| 398 | return 0; |
| 399 | } |
| 400 | |
| 401 | static const struct seq_operations pwm_seq_ops = { |
| 402 | .start = pwm_seq_start, |
| 403 | .next = pwm_seq_next, |
| 404 | .stop = pwm_seq_stop, |
| 405 | .show = pwm_seq_show, |
| 406 | }; |
| 407 | |
| 408 | static int pwm_seq_open(struct inode *inode, struct file *file) |
| 409 | { |
| 410 | return seq_open(file, &pwm_seq_ops); |
| 411 | } |
| 412 | |
| 413 | static const struct file_operations pwm_debugfs_ops = { |
| 414 | .owner = THIS_MODULE, |
| 415 | .open = pwm_seq_open, |
| 416 | .read = seq_read, |
| 417 | .llseek = seq_lseek, |
| 418 | .release = seq_release, |
| 419 | }; |
| 420 | |
| 421 | static int __init pwm_debugfs_init(void) |
| 422 | { |
| 423 | debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL, |
| 424 | &pwm_debugfs_ops); |
| 425 | |
| 426 | return 0; |
| 427 | } |
| 428 | |
| 429 | subsys_initcall(pwm_debugfs_init); |
| 430 | #endif /* CONFIG_DEBUG_FS */ |