| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* |
| 3 | * A simple sysfs interface for the generic PWM framework |
| 4 | * |
| 5 | * Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com> |
| 6 | * |
| 7 | * Based on previous work by Lars Poeschel <poeschel@lemonage.de> |
| 8 | */ |
| 9 | |
| 10 | #include <linux/device.h> |
| 11 | #include <linux/mutex.h> |
| 12 | #include <linux/err.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <linux/kdev_t.h> |
| 15 | #include <linux/pwm.h> |
| 16 | |
| 17 | struct pwm_export { |
| 18 | struct device child; |
| 19 | struct pwm_device *pwm; |
| 20 | struct mutex lock; |
| 21 | struct pwm_state suspend; |
| 22 | }; |
| 23 | |
| 24 | static struct pwm_export *child_to_pwm_export(struct device *child) |
| 25 | { |
| 26 | return container_of(child, struct pwm_export, child); |
| 27 | } |
| 28 | |
| 29 | static struct pwm_device *child_to_pwm_device(struct device *child) |
| 30 | { |
| 31 | struct pwm_export *export = child_to_pwm_export(child); |
| 32 | |
| 33 | return export->pwm; |
| 34 | } |
| 35 | |
| 36 | static ssize_t period_show(struct device *child, |
| 37 | struct device_attribute *attr, |
| 38 | char *buf) |
| 39 | { |
| 40 | const struct pwm_device *pwm = child_to_pwm_device(child); |
| 41 | struct pwm_state state; |
| 42 | |
| 43 | pwm_get_state(pwm, &state); |
| 44 | |
| 45 | return sysfs_emit(buf, "%llu\n", state.period); |
| 46 | } |
| 47 | |
| 48 | static ssize_t period_store(struct device *child, |
| 49 | struct device_attribute *attr, |
| 50 | const char *buf, size_t size) |
| 51 | { |
| 52 | struct pwm_export *export = child_to_pwm_export(child); |
| 53 | struct pwm_device *pwm = export->pwm; |
| 54 | struct pwm_state state; |
| 55 | u64 val; |
| 56 | int ret; |
| 57 | |
| 58 | ret = kstrtou64(buf, 0, &val); |
| 59 | if (ret) |
| 60 | return ret; |
| 61 | |
| 62 | mutex_lock(&export->lock); |
| 63 | pwm_get_state(pwm, &state); |
| 64 | state.period = val; |
| 65 | ret = pwm_apply_state(pwm, &state); |
| 66 | mutex_unlock(&export->lock); |
| 67 | |
| 68 | return ret ? : size; |
| 69 | } |
| 70 | |
| 71 | static ssize_t duty_cycle_show(struct device *child, |
| 72 | struct device_attribute *attr, |
| 73 | char *buf) |
| 74 | { |
| 75 | const struct pwm_device *pwm = child_to_pwm_device(child); |
| 76 | struct pwm_state state; |
| 77 | |
| 78 | pwm_get_state(pwm, &state); |
| 79 | |
| 80 | return sysfs_emit(buf, "%llu\n", state.duty_cycle); |
| 81 | } |
| 82 | |
| 83 | static ssize_t duty_cycle_store(struct device *child, |
| 84 | struct device_attribute *attr, |
| 85 | const char *buf, size_t size) |
| 86 | { |
| 87 | struct pwm_export *export = child_to_pwm_export(child); |
| 88 | struct pwm_device *pwm = export->pwm; |
| 89 | struct pwm_state state; |
| 90 | u64 val; |
| 91 | int ret; |
| 92 | |
| 93 | ret = kstrtou64(buf, 0, &val); |
| 94 | if (ret) |
| 95 | return ret; |
| 96 | |
| 97 | mutex_lock(&export->lock); |
| 98 | pwm_get_state(pwm, &state); |
| 99 | state.duty_cycle = val; |
| 100 | ret = pwm_apply_state(pwm, &state); |
| 101 | mutex_unlock(&export->lock); |
| 102 | |
| 103 | return ret ? : size; |
| 104 | } |
| 105 | |
| 106 | static ssize_t enable_show(struct device *child, |
| 107 | struct device_attribute *attr, |
| 108 | char *buf) |
| 109 | { |
| 110 | const struct pwm_device *pwm = child_to_pwm_device(child); |
| 111 | struct pwm_state state; |
| 112 | |
| 113 | pwm_get_state(pwm, &state); |
| 114 | |
| 115 | return sysfs_emit(buf, "%d\n", state.enabled); |
| 116 | } |
| 117 | |
| 118 | static ssize_t enable_store(struct device *child, |
| 119 | struct device_attribute *attr, |
| 120 | const char *buf, size_t size) |
| 121 | { |
| 122 | struct pwm_export *export = child_to_pwm_export(child); |
| 123 | struct pwm_device *pwm = export->pwm; |
| 124 | struct pwm_state state; |
| 125 | int val, ret; |
| 126 | |
| 127 | ret = kstrtoint(buf, 0, &val); |
| 128 | if (ret) |
| 129 | return ret; |
| 130 | |
| 131 | mutex_lock(&export->lock); |
| 132 | |
| 133 | pwm_get_state(pwm, &state); |
| 134 | |
| 135 | switch (val) { |
| 136 | case 0: |
| 137 | state.enabled = false; |
| 138 | break; |
| 139 | case 1: |
| 140 | state.enabled = true; |
| 141 | break; |
| 142 | default: |
| 143 | ret = -EINVAL; |
| 144 | goto unlock; |
| 145 | } |
| 146 | |
| 147 | ret = pwm_apply_state(pwm, &state); |
| 148 | |
| 149 | unlock: |
| 150 | mutex_unlock(&export->lock); |
| 151 | return ret ? : size; |
| 152 | } |
| 153 | |
| 154 | static ssize_t polarity_show(struct device *child, |
| 155 | struct device_attribute *attr, |
| 156 | char *buf) |
| 157 | { |
| 158 | const struct pwm_device *pwm = child_to_pwm_device(child); |
| 159 | const char *polarity = "unknown"; |
| 160 | struct pwm_state state; |
| 161 | |
| 162 | pwm_get_state(pwm, &state); |
| 163 | |
| 164 | switch (state.polarity) { |
| 165 | case PWM_POLARITY_NORMAL: |
| 166 | polarity = "normal"; |
| 167 | break; |
| 168 | |
| 169 | case PWM_POLARITY_INVERSED: |
| 170 | polarity = "inversed"; |
| 171 | break; |
| 172 | } |
| 173 | |
| 174 | return sysfs_emit(buf, "%s\n", polarity); |
| 175 | } |
| 176 | |
| 177 | static ssize_t polarity_store(struct device *child, |
| 178 | struct device_attribute *attr, |
| 179 | const char *buf, size_t size) |
| 180 | { |
| 181 | struct pwm_export *export = child_to_pwm_export(child); |
| 182 | struct pwm_device *pwm = export->pwm; |
| 183 | enum pwm_polarity polarity; |
| 184 | struct pwm_state state; |
| 185 | int ret; |
| 186 | |
| 187 | if (sysfs_streq(buf, "normal")) |
| 188 | polarity = PWM_POLARITY_NORMAL; |
| 189 | else if (sysfs_streq(buf, "inversed")) |
| 190 | polarity = PWM_POLARITY_INVERSED; |
| 191 | else |
| 192 | return -EINVAL; |
| 193 | |
| 194 | mutex_lock(&export->lock); |
| 195 | pwm_get_state(pwm, &state); |
| 196 | state.polarity = polarity; |
| 197 | ret = pwm_apply_state(pwm, &state); |
| 198 | mutex_unlock(&export->lock); |
| 199 | |
| 200 | return ret ? : size; |
| 201 | } |
| 202 | |
| 203 | static ssize_t capture_show(struct device *child, |
| 204 | struct device_attribute *attr, |
| 205 | char *buf) |
| 206 | { |
| 207 | struct pwm_device *pwm = child_to_pwm_device(child); |
| 208 | struct pwm_capture result; |
| 209 | int ret; |
| 210 | |
| 211 | ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ)); |
| 212 | if (ret) |
| 213 | return ret; |
| 214 | |
| 215 | return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle); |
| 216 | } |
| 217 | |
| 218 | static DEVICE_ATTR_RW(period); |
| 219 | static DEVICE_ATTR_RW(duty_cycle); |
| 220 | static DEVICE_ATTR_RW(enable); |
| 221 | static DEVICE_ATTR_RW(polarity); |
| 222 | static DEVICE_ATTR_RO(capture); |
| 223 | |
| 224 | static struct attribute *pwm_attrs[] = { |
| 225 | &dev_attr_period.attr, |
| 226 | &dev_attr_duty_cycle.attr, |
| 227 | &dev_attr_enable.attr, |
| 228 | &dev_attr_polarity.attr, |
| 229 | &dev_attr_capture.attr, |
| 230 | NULL |
| 231 | }; |
| 232 | ATTRIBUTE_GROUPS(pwm); |
| 233 | |
| 234 | static void pwm_export_release(struct device *child) |
| 235 | { |
| 236 | struct pwm_export *export = child_to_pwm_export(child); |
| 237 | |
| 238 | kfree(export); |
| 239 | } |
| 240 | |
| 241 | static int pwm_export_child(struct device *parent, struct pwm_device *pwm) |
| 242 | { |
| 243 | struct pwm_export *export; |
| 244 | char *pwm_prop[2]; |
| 245 | int ret; |
| 246 | |
| 247 | if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags)) |
| 248 | return -EBUSY; |
| 249 | |
| 250 | export = kzalloc(sizeof(*export), GFP_KERNEL); |
| 251 | if (!export) { |
| 252 | clear_bit(PWMF_EXPORTED, &pwm->flags); |
| 253 | return -ENOMEM; |
| 254 | } |
| 255 | |
| 256 | export->pwm = pwm; |
| 257 | mutex_init(&export->lock); |
| 258 | |
| 259 | export->child.release = pwm_export_release; |
| 260 | export->child.parent = parent; |
| 261 | export->child.devt = MKDEV(0, 0); |
| 262 | export->child.groups = pwm_groups; |
| 263 | dev_set_name(&export->child, "pwm%u", pwm->hwpwm); |
| 264 | |
| 265 | ret = device_register(&export->child); |
| 266 | if (ret) { |
| 267 | clear_bit(PWMF_EXPORTED, &pwm->flags); |
| 268 | put_device(&export->child); |
| 269 | export = NULL; |
| 270 | return ret; |
| 271 | } |
| 272 | pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm); |
| 273 | pwm_prop[1] = NULL; |
| 274 | kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop); |
| 275 | kfree(pwm_prop[0]); |
| 276 | |
| 277 | return 0; |
| 278 | } |
| 279 | |
| 280 | static int pwm_unexport_match(struct device *child, void *data) |
| 281 | { |
| 282 | return child_to_pwm_device(child) == data; |
| 283 | } |
| 284 | |
| 285 | static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm) |
| 286 | { |
| 287 | struct device *child; |
| 288 | char *pwm_prop[2]; |
| 289 | |
| 290 | if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) |
| 291 | return -ENODEV; |
| 292 | |
| 293 | child = device_find_child(parent, pwm, pwm_unexport_match); |
| 294 | if (!child) |
| 295 | return -ENODEV; |
| 296 | |
| 297 | pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm); |
| 298 | pwm_prop[1] = NULL; |
| 299 | kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop); |
| 300 | kfree(pwm_prop[0]); |
| 301 | |
| 302 | /* for device_find_child() */ |
| 303 | put_device(child); |
| 304 | device_unregister(child); |
| 305 | pwm_put(pwm); |
| 306 | |
| 307 | return 0; |
| 308 | } |
| 309 | |
| 310 | static ssize_t export_store(struct device *parent, |
| 311 | struct device_attribute *attr, |
| 312 | const char *buf, size_t len) |
| 313 | { |
| 314 | struct pwm_chip *chip = dev_get_drvdata(parent); |
| 315 | struct pwm_device *pwm; |
| 316 | unsigned int hwpwm; |
| 317 | int ret; |
| 318 | |
| 319 | ret = kstrtouint(buf, 0, &hwpwm); |
| 320 | if (ret < 0) |
| 321 | return ret; |
| 322 | |
| 323 | if (hwpwm >= chip->npwm) |
| 324 | return -ENODEV; |
| 325 | |
| 326 | pwm = pwm_request_from_chip(chip, hwpwm, "sysfs"); |
| 327 | if (IS_ERR(pwm)) |
| 328 | return PTR_ERR(pwm); |
| 329 | |
| 330 | ret = pwm_export_child(parent, pwm); |
| 331 | if (ret < 0) |
| 332 | pwm_put(pwm); |
| 333 | |
| 334 | return ret ? : len; |
| 335 | } |
| 336 | static DEVICE_ATTR_WO(export); |
| 337 | |
| 338 | static ssize_t unexport_store(struct device *parent, |
| 339 | struct device_attribute *attr, |
| 340 | const char *buf, size_t len) |
| 341 | { |
| 342 | struct pwm_chip *chip = dev_get_drvdata(parent); |
| 343 | unsigned int hwpwm; |
| 344 | int ret; |
| 345 | |
| 346 | ret = kstrtouint(buf, 0, &hwpwm); |
| 347 | if (ret < 0) |
| 348 | return ret; |
| 349 | |
| 350 | if (hwpwm >= chip->npwm) |
| 351 | return -ENODEV; |
| 352 | |
| 353 | ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]); |
| 354 | |
| 355 | return ret ? : len; |
| 356 | } |
| 357 | static DEVICE_ATTR_WO(unexport); |
| 358 | |
| 359 | static ssize_t npwm_show(struct device *parent, struct device_attribute *attr, |
| 360 | char *buf) |
| 361 | { |
| 362 | const struct pwm_chip *chip = dev_get_drvdata(parent); |
| 363 | |
| 364 | return sysfs_emit(buf, "%u\n", chip->npwm); |
| 365 | } |
| 366 | static DEVICE_ATTR_RO(npwm); |
| 367 | |
| 368 | static struct attribute *pwm_chip_attrs[] = { |
| 369 | &dev_attr_export.attr, |
| 370 | &dev_attr_unexport.attr, |
| 371 | &dev_attr_npwm.attr, |
| 372 | NULL, |
| 373 | }; |
| 374 | ATTRIBUTE_GROUPS(pwm_chip); |
| 375 | |
| 376 | /* takes export->lock on success */ |
| 377 | static struct pwm_export *pwm_class_get_state(struct device *parent, |
| 378 | struct pwm_device *pwm, |
| 379 | struct pwm_state *state) |
| 380 | { |
| 381 | struct device *child; |
| 382 | struct pwm_export *export; |
| 383 | |
| 384 | if (!test_bit(PWMF_EXPORTED, &pwm->flags)) |
| 385 | return NULL; |
| 386 | |
| 387 | child = device_find_child(parent, pwm, pwm_unexport_match); |
| 388 | if (!child) |
| 389 | return NULL; |
| 390 | |
| 391 | export = child_to_pwm_export(child); |
| 392 | put_device(child); /* for device_find_child() */ |
| 393 | |
| 394 | mutex_lock(&export->lock); |
| 395 | pwm_get_state(pwm, state); |
| 396 | |
| 397 | return export; |
| 398 | } |
| 399 | |
| 400 | static int pwm_class_apply_state(struct pwm_export *export, |
| 401 | struct pwm_device *pwm, |
| 402 | struct pwm_state *state) |
| 403 | { |
| 404 | int ret = pwm_apply_state(pwm, state); |
| 405 | |
| 406 | /* release lock taken in pwm_class_get_state */ |
| 407 | mutex_unlock(&export->lock); |
| 408 | |
| 409 | return ret; |
| 410 | } |
| 411 | |
| 412 | static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm) |
| 413 | { |
| 414 | struct pwm_chip *chip = dev_get_drvdata(parent); |
| 415 | unsigned int i; |
| 416 | int ret = 0; |
| 417 | |
| 418 | for (i = 0; i < npwm; i++) { |
| 419 | struct pwm_device *pwm = &chip->pwms[i]; |
| 420 | struct pwm_state state; |
| 421 | struct pwm_export *export; |
| 422 | |
| 423 | export = pwm_class_get_state(parent, pwm, &state); |
| 424 | if (!export) |
| 425 | continue; |
| 426 | |
| 427 | state.enabled = export->suspend.enabled; |
| 428 | ret = pwm_class_apply_state(export, pwm, &state); |
| 429 | if (ret < 0) |
| 430 | break; |
| 431 | } |
| 432 | |
| 433 | return ret; |
| 434 | } |
| 435 | |
| 436 | static int pwm_class_suspend(struct device *parent) |
| 437 | { |
| 438 | struct pwm_chip *chip = dev_get_drvdata(parent); |
| 439 | unsigned int i; |
| 440 | int ret = 0; |
| 441 | |
| 442 | for (i = 0; i < chip->npwm; i++) { |
| 443 | struct pwm_device *pwm = &chip->pwms[i]; |
| 444 | struct pwm_state state; |
| 445 | struct pwm_export *export; |
| 446 | |
| 447 | export = pwm_class_get_state(parent, pwm, &state); |
| 448 | if (!export) |
| 449 | continue; |
| 450 | |
| 451 | export->suspend = state; |
| 452 | state.enabled = false; |
| 453 | ret = pwm_class_apply_state(export, pwm, &state); |
| 454 | if (ret < 0) { |
| 455 | /* |
| 456 | * roll back the PWM devices that were disabled by |
| 457 | * this suspend function. |
| 458 | */ |
| 459 | pwm_class_resume_npwm(parent, i); |
| 460 | break; |
| 461 | } |
| 462 | } |
| 463 | |
| 464 | return ret; |
| 465 | } |
| 466 | |
| 467 | static int pwm_class_resume(struct device *parent) |
| 468 | { |
| 469 | struct pwm_chip *chip = dev_get_drvdata(parent); |
| 470 | |
| 471 | return pwm_class_resume_npwm(parent, chip->npwm); |
| 472 | } |
| 473 | |
| 474 | static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume); |
| 475 | |
| 476 | static struct class pwm_class = { |
| 477 | .name = "pwm", |
| 478 | .dev_groups = pwm_chip_groups, |
| 479 | .pm = pm_sleep_ptr(&pwm_class_pm_ops), |
| 480 | }; |
| 481 | |
| 482 | static int pwmchip_sysfs_match(struct device *parent, const void *data) |
| 483 | { |
| 484 | return dev_get_drvdata(parent) == data; |
| 485 | } |
| 486 | |
| 487 | void pwmchip_sysfs_export(struct pwm_chip *chip) |
| 488 | { |
| 489 | struct device *parent; |
| 490 | |
| 491 | /* |
| 492 | * If device_create() fails the pwm_chip is still usable by |
| 493 | * the kernel it's just not exported. |
| 494 | */ |
| 495 | parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip, |
| 496 | "pwmchip%d", chip->base); |
| 497 | if (IS_ERR(parent)) { |
| 498 | dev_warn(chip->dev, |
| 499 | "device_create failed for pwm_chip sysfs export\n"); |
| 500 | } |
| 501 | } |
| 502 | |
| 503 | void pwmchip_sysfs_unexport(struct pwm_chip *chip) |
| 504 | { |
| 505 | struct device *parent; |
| 506 | unsigned int i; |
| 507 | |
| 508 | parent = class_find_device(&pwm_class, NULL, chip, |
| 509 | pwmchip_sysfs_match); |
| 510 | if (!parent) |
| 511 | return; |
| 512 | |
| 513 | for (i = 0; i < chip->npwm; i++) { |
| 514 | struct pwm_device *pwm = &chip->pwms[i]; |
| 515 | |
| 516 | if (test_bit(PWMF_EXPORTED, &pwm->flags)) |
| 517 | pwm_unexport_child(parent, pwm); |
| 518 | } |
| 519 | |
| 520 | put_device(parent); |
| 521 | device_unregister(parent); |
| 522 | } |
| 523 | |
| 524 | static int __init pwm_sysfs_init(void) |
| 525 | { |
| 526 | return class_register(&pwm_class); |
| 527 | } |
| 528 | subsys_initcall(pwm_sysfs_init); |