1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_PWM_H 3 #define __LINUX_PWM_H 4 5 #include <linux/err.h> 6 #include <linux/mutex.h> 7 #include <linux/of.h> 8 9 struct pwm_capture; 10 struct seq_file; 11 12 struct pwm_chip; 13 14 /** 15 * enum pwm_polarity - polarity of a PWM signal 16 * @PWM_POLARITY_NORMAL: a high signal for the duration of the duty- 17 * cycle, followed by a low signal for the remainder of the pulse 18 * period 19 * @PWM_POLARITY_INVERSED: a low signal for the duration of the duty- 20 * cycle, followed by a high signal for the remainder of the pulse 21 * period 22 */ 23 enum pwm_polarity { 24 PWM_POLARITY_NORMAL, 25 PWM_POLARITY_INVERSED, 26 }; 27 28 /** 29 * struct pwm_args - board-dependent PWM arguments 30 * @period: reference period 31 * @polarity: reference polarity 32 * 33 * This structure describes board-dependent arguments attached to a PWM 34 * device. These arguments are usually retrieved from the PWM lookup table or 35 * device tree. 36 * 37 * Do not confuse this with the PWM state: PWM arguments represent the initial 38 * configuration that users want to use on this PWM device rather than the 39 * current PWM hardware state. 40 */ 41 struct pwm_args { 42 unsigned int period; 43 enum pwm_polarity polarity; 44 }; 45 46 enum { 47 PWMF_REQUESTED = 1 << 0, 48 PWMF_EXPORTED = 1 << 1, 49 }; 50 51 /* 52 * struct pwm_state - state of a PWM channel 53 * @period: PWM period (in nanoseconds) 54 * @duty_cycle: PWM duty cycle (in nanoseconds) 55 * @polarity: PWM polarity 56 * @enabled: PWM enabled status 57 */ 58 struct pwm_state { 59 unsigned int period; 60 unsigned int duty_cycle; 61 enum pwm_polarity polarity; 62 bool enabled; 63 }; 64 65 /** 66 * struct pwm_device - PWM channel object 67 * @label: name of the PWM device 68 * @flags: flags associated with the PWM device 69 * @hwpwm: per-chip relative index of the PWM device 70 * @pwm: global index of the PWM device 71 * @chip: PWM chip providing this PWM device 72 * @chip_data: chip-private data associated with the PWM device 73 * @args: PWM arguments 74 * @state: curent PWM channel state 75 */ 76 struct pwm_device { 77 const char *label; 78 unsigned long flags; 79 unsigned int hwpwm; 80 unsigned int pwm; 81 struct pwm_chip *chip; 82 void *chip_data; 83 84 struct pwm_args args; 85 struct pwm_state state; 86 }; 87 88 /** 89 * pwm_get_state() - retrieve the current PWM state 90 * @pwm: PWM device 91 * @state: state to fill with the current PWM state 92 */ 93 static inline void pwm_get_state(const struct pwm_device *pwm, 94 struct pwm_state *state) 95 { 96 *state = pwm->state; 97 } 98 99 static inline bool pwm_is_enabled(const struct pwm_device *pwm) 100 { 101 struct pwm_state state; 102 103 pwm_get_state(pwm, &state); 104 105 return state.enabled; 106 } 107 108 static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period) 109 { 110 if (pwm) 111 pwm->state.period = period; 112 } 113 114 static inline unsigned int pwm_get_period(const struct pwm_device *pwm) 115 { 116 struct pwm_state state; 117 118 pwm_get_state(pwm, &state); 119 120 return state.period; 121 } 122 123 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty) 124 { 125 if (pwm) 126 pwm->state.duty_cycle = duty; 127 } 128 129 static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm) 130 { 131 struct pwm_state state; 132 133 pwm_get_state(pwm, &state); 134 135 return state.duty_cycle; 136 } 137 138 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) 139 { 140 struct pwm_state state; 141 142 pwm_get_state(pwm, &state); 143 144 return state.polarity; 145 } 146 147 static inline void pwm_get_args(const struct pwm_device *pwm, 148 struct pwm_args *args) 149 { 150 *args = pwm->args; 151 } 152 153 /** 154 * pwm_init_state() - prepare a new state to be applied with pwm_apply_state() 155 * @pwm: PWM device 156 * @state: state to fill with the prepared PWM state 157 * 158 * This functions prepares a state that can later be tweaked and applied 159 * to the PWM device with pwm_apply_state(). This is a convenient function 160 * that first retrieves the current PWM state and the replaces the period 161 * and polarity fields with the reference values defined in pwm->args. 162 * Once the function returns, you can adjust the ->enabled and ->duty_cycle 163 * fields according to your needs before calling pwm_apply_state(). 164 * 165 * ->duty_cycle is initially set to zero to avoid cases where the current 166 * ->duty_cycle value exceed the pwm_args->period one, which would trigger 167 * an error if the user calls pwm_apply_state() without adjusting ->duty_cycle 168 * first. 169 */ 170 static inline void pwm_init_state(const struct pwm_device *pwm, 171 struct pwm_state *state) 172 { 173 struct pwm_args args; 174 175 /* First get the current state. */ 176 pwm_get_state(pwm, state); 177 178 /* Then fill it with the reference config */ 179 pwm_get_args(pwm, &args); 180 181 state->period = args.period; 182 state->polarity = args.polarity; 183 state->duty_cycle = 0; 184 } 185 186 /** 187 * pwm_get_relative_duty_cycle() - Get a relative duty cycle value 188 * @state: PWM state to extract the duty cycle from 189 * @scale: target scale of the relative duty cycle 190 * 191 * This functions converts the absolute duty cycle stored in @state (expressed 192 * in nanosecond) into a value relative to the period. 193 * 194 * For example if you want to get the duty_cycle expressed in percent, call: 195 * 196 * pwm_get_state(pwm, &state); 197 * duty = pwm_get_relative_duty_cycle(&state, 100); 198 */ 199 static inline unsigned int 200 pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) 201 { 202 if (!state->period) 203 return 0; 204 205 return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale, 206 state->period); 207 } 208 209 /** 210 * pwm_set_relative_duty_cycle() - Set a relative duty cycle value 211 * @state: PWM state to fill 212 * @duty_cycle: relative duty cycle value 213 * @scale: scale in which @duty_cycle is expressed 214 * 215 * This functions converts a relative into an absolute duty cycle (expressed 216 * in nanoseconds), and puts the result in state->duty_cycle. 217 * 218 * For example if you want to configure a 50% duty cycle, call: 219 * 220 * pwm_init_state(pwm, &state); 221 * pwm_set_relative_duty_cycle(&state, 50, 100); 222 * pwm_apply_state(pwm, &state); 223 * 224 * This functions returns -EINVAL if @duty_cycle and/or @scale are 225 * inconsistent (@scale == 0 or @duty_cycle > @scale). 226 */ 227 static inline int 228 pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, 229 unsigned int scale) 230 { 231 if (!scale || duty_cycle > scale) 232 return -EINVAL; 233 234 state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle * 235 state->period, 236 scale); 237 238 return 0; 239 } 240 241 /** 242 * struct pwm_ops - PWM controller operations 243 * @request: optional hook for requesting a PWM 244 * @free: optional hook for freeing a PWM 245 * @capture: capture and report PWM signal 246 * @apply: atomically apply a new PWM config. The state argument 247 * should be adjusted with the real hardware config (if the 248 * approximate the period or duty_cycle value, state should 249 * reflect it) 250 * @get_state: get the current PWM state. This function is only 251 * called once per PWM device when the PWM chip is 252 * registered. 253 * @owner: helps prevent removal of modules exporting active PWMs 254 * @config: configure duty cycles and period length for this PWM 255 * @set_polarity: configure the polarity of this PWM 256 * @enable: enable PWM output toggling 257 * @disable: disable PWM output toggling 258 */ 259 struct pwm_ops { 260 int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); 261 void (*free)(struct pwm_chip *chip, struct pwm_device *pwm); 262 int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm, 263 struct pwm_capture *result, unsigned long timeout); 264 int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, 265 struct pwm_state *state); 266 void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, 267 struct pwm_state *state); 268 struct module *owner; 269 270 /* Only used by legacy drivers */ 271 int (*config)(struct pwm_chip *chip, struct pwm_device *pwm, 272 int duty_ns, int period_ns); 273 int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm, 274 enum pwm_polarity polarity); 275 int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); 276 void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm); 277 }; 278 279 /** 280 * struct pwm_chip - abstract a PWM controller 281 * @dev: device providing the PWMs 282 * @ops: callbacks for this PWM controller 283 * @base: number of first PWM controlled by this chip 284 * @npwm: number of PWMs controlled by this chip 285 * @of_xlate: request a PWM device given a device tree PWM specifier 286 * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier 287 * @list: list node for internal use 288 * @pwms: array of PWM devices allocated by the framework 289 */ 290 struct pwm_chip { 291 struct device *dev; 292 const struct pwm_ops *ops; 293 int base; 294 unsigned int npwm; 295 296 struct pwm_device * (*of_xlate)(struct pwm_chip *pc, 297 const struct of_phandle_args *args); 298 unsigned int of_pwm_n_cells; 299 300 /* only used internally by the PWM framework */ 301 struct list_head list; 302 struct pwm_device *pwms; 303 }; 304 305 /** 306 * struct pwm_capture - PWM capture data 307 * @period: period of the PWM signal (in nanoseconds) 308 * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) 309 */ 310 struct pwm_capture { 311 unsigned int period; 312 unsigned int duty_cycle; 313 }; 314 315 #if IS_ENABLED(CONFIG_PWM) 316 /* PWM user APIs */ 317 struct pwm_device *pwm_request(int pwm_id, const char *label); 318 void pwm_free(struct pwm_device *pwm); 319 int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state); 320 int pwm_adjust_config(struct pwm_device *pwm); 321 322 /** 323 * pwm_config() - change a PWM device configuration 324 * @pwm: PWM device 325 * @duty_ns: "on" time (in nanoseconds) 326 * @period_ns: duration (in nanoseconds) of one cycle 327 * 328 * Returns: 0 on success or a negative error code on failure. 329 */ 330 static inline int pwm_config(struct pwm_device *pwm, int duty_ns, 331 int period_ns) 332 { 333 struct pwm_state state; 334 335 if (!pwm) 336 return -EINVAL; 337 338 if (duty_ns < 0 || period_ns < 0) 339 return -EINVAL; 340 341 pwm_get_state(pwm, &state); 342 if (state.duty_cycle == duty_ns && state.period == period_ns) 343 return 0; 344 345 state.duty_cycle = duty_ns; 346 state.period = period_ns; 347 return pwm_apply_state(pwm, &state); 348 } 349 350 /** 351 * pwm_enable() - start a PWM output toggling 352 * @pwm: PWM device 353 * 354 * Returns: 0 on success or a negative error code on failure. 355 */ 356 static inline int pwm_enable(struct pwm_device *pwm) 357 { 358 struct pwm_state state; 359 360 if (!pwm) 361 return -EINVAL; 362 363 pwm_get_state(pwm, &state); 364 if (state.enabled) 365 return 0; 366 367 state.enabled = true; 368 return pwm_apply_state(pwm, &state); 369 } 370 371 /** 372 * pwm_disable() - stop a PWM output toggling 373 * @pwm: PWM device 374 */ 375 static inline void pwm_disable(struct pwm_device *pwm) 376 { 377 struct pwm_state state; 378 379 if (!pwm) 380 return; 381 382 pwm_get_state(pwm, &state); 383 if (!state.enabled) 384 return; 385 386 state.enabled = false; 387 pwm_apply_state(pwm, &state); 388 } 389 390 /* PWM provider APIs */ 391 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, 392 unsigned long timeout); 393 int pwm_set_chip_data(struct pwm_device *pwm, void *data); 394 void *pwm_get_chip_data(struct pwm_device *pwm); 395 396 int pwmchip_add_with_polarity(struct pwm_chip *chip, 397 enum pwm_polarity polarity); 398 int pwmchip_add(struct pwm_chip *chip); 399 int pwmchip_remove(struct pwm_chip *chip); 400 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, 401 unsigned int index, 402 const char *label); 403 404 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, 405 const struct of_phandle_args *args); 406 407 struct pwm_device *pwm_get(struct device *dev, const char *con_id); 408 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id); 409 void pwm_put(struct pwm_device *pwm); 410 411 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id); 412 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, 413 const char *con_id); 414 void devm_pwm_put(struct device *dev, struct pwm_device *pwm); 415 #else 416 static inline struct pwm_device *pwm_request(int pwm_id, const char *label) 417 { 418 return ERR_PTR(-ENODEV); 419 } 420 421 static inline void pwm_free(struct pwm_device *pwm) 422 { 423 } 424 425 static inline int pwm_apply_state(struct pwm_device *pwm, 426 const struct pwm_state *state) 427 { 428 return -ENOTSUPP; 429 } 430 431 static inline int pwm_adjust_config(struct pwm_device *pwm) 432 { 433 return -ENOTSUPP; 434 } 435 436 static inline int pwm_config(struct pwm_device *pwm, int duty_ns, 437 int period_ns) 438 { 439 return -EINVAL; 440 } 441 442 static inline int pwm_capture(struct pwm_device *pwm, 443 struct pwm_capture *result, 444 unsigned long timeout) 445 { 446 return -EINVAL; 447 } 448 449 static inline int pwm_enable(struct pwm_device *pwm) 450 { 451 return -EINVAL; 452 } 453 454 static inline void pwm_disable(struct pwm_device *pwm) 455 { 456 } 457 458 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) 459 { 460 return -EINVAL; 461 } 462 463 static inline void *pwm_get_chip_data(struct pwm_device *pwm) 464 { 465 return NULL; 466 } 467 468 static inline int pwmchip_add(struct pwm_chip *chip) 469 { 470 return -EINVAL; 471 } 472 473 static inline int pwmchip_add_inversed(struct pwm_chip *chip) 474 { 475 return -EINVAL; 476 } 477 478 static inline int pwmchip_remove(struct pwm_chip *chip) 479 { 480 return -EINVAL; 481 } 482 483 static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, 484 unsigned int index, 485 const char *label) 486 { 487 return ERR_PTR(-ENODEV); 488 } 489 490 static inline struct pwm_device *pwm_get(struct device *dev, 491 const char *consumer) 492 { 493 return ERR_PTR(-ENODEV); 494 } 495 496 static inline struct pwm_device *of_pwm_get(struct device_node *np, 497 const char *con_id) 498 { 499 return ERR_PTR(-ENODEV); 500 } 501 502 static inline void pwm_put(struct pwm_device *pwm) 503 { 504 } 505 506 static inline struct pwm_device *devm_pwm_get(struct device *dev, 507 const char *consumer) 508 { 509 return ERR_PTR(-ENODEV); 510 } 511 512 static inline struct pwm_device *devm_of_pwm_get(struct device *dev, 513 struct device_node *np, 514 const char *con_id) 515 { 516 return ERR_PTR(-ENODEV); 517 } 518 519 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm) 520 { 521 } 522 #endif 523 524 static inline void pwm_apply_args(struct pwm_device *pwm) 525 { 526 struct pwm_state state = { }; 527 528 /* 529 * PWM users calling pwm_apply_args() expect to have a fresh config 530 * where the polarity and period are set according to pwm_args info. 531 * The problem is, polarity can only be changed when the PWM is 532 * disabled. 533 * 534 * PWM drivers supporting hardware readout may declare the PWM device 535 * as enabled, and prevent polarity setting, which changes from the 536 * existing behavior, where all PWM devices are declared as disabled 537 * at startup (even if they are actually enabled), thus authorizing 538 * polarity setting. 539 * 540 * To fulfill this requirement, we apply a new state which disables 541 * the PWM device and set the reference period and polarity config. 542 * 543 * Note that PWM users requiring a smooth handover between the 544 * bootloader and the kernel (like critical regulators controlled by 545 * PWM devices) will have to switch to the atomic API and avoid calling 546 * pwm_apply_args(). 547 */ 548 549 state.enabled = false; 550 state.polarity = pwm->args.polarity; 551 state.period = pwm->args.period; 552 553 pwm_apply_state(pwm, &state); 554 } 555 556 struct pwm_lookup { 557 struct list_head list; 558 const char *provider; 559 unsigned int index; 560 const char *dev_id; 561 const char *con_id; 562 unsigned int period; 563 enum pwm_polarity polarity; 564 const char *module; /* optional, may be NULL */ 565 }; 566 567 #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ 568 _period, _polarity, _module) \ 569 { \ 570 .provider = _provider, \ 571 .index = _index, \ 572 .dev_id = _dev_id, \ 573 .con_id = _con_id, \ 574 .period = _period, \ 575 .polarity = _polarity, \ 576 .module = _module, \ 577 } 578 579 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ 580 PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ 581 _polarity, NULL) 582 583 #if IS_ENABLED(CONFIG_PWM) 584 void pwm_add_table(struct pwm_lookup *table, size_t num); 585 void pwm_remove_table(struct pwm_lookup *table, size_t num); 586 #else 587 static inline void pwm_add_table(struct pwm_lookup *table, size_t num) 588 { 589 } 590 591 static inline void pwm_remove_table(struct pwm_lookup *table, size_t num) 592 { 593 } 594 #endif 595 596 #ifdef CONFIG_PWM_SYSFS 597 void pwmchip_sysfs_export(struct pwm_chip *chip); 598 void pwmchip_sysfs_unexport(struct pwm_chip *chip); 599 #else 600 static inline void pwmchip_sysfs_export(struct pwm_chip *chip) 601 { 602 } 603 604 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip) 605 { 606 } 607 #endif /* CONFIG_PWM_SYSFS */ 608 609 #endif /* __LINUX_PWM_H */ 610