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 9struct pwm_chip; 10 11/** 12 * enum pwm_polarity - polarity of a PWM signal 13 * @PWM_POLARITY_NORMAL: a high signal for the duration of the duty- 14 * cycle, followed by a low signal for the remainder of the pulse 15 * period 16 * @PWM_POLARITY_INVERSED: a low signal for the duration of the duty- 17 * cycle, followed by a high signal for the remainder of the pulse 18 * period 19 */ 20enum pwm_polarity { 21 PWM_POLARITY_NORMAL, 22 PWM_POLARITY_INVERSED, 23}; 24 25/** 26 * struct pwm_args - board-dependent PWM arguments 27 * @period: reference period 28 * @polarity: reference polarity 29 * 30 * This structure describes board-dependent arguments attached to a PWM 31 * device. These arguments are usually retrieved from the PWM lookup table or 32 * device tree. 33 * 34 * Do not confuse this with the PWM state: PWM arguments represent the initial 35 * configuration that users want to use on this PWM device rather than the 36 * current PWM hardware state. 37 */ 38struct pwm_args { 39 u64 period; 40 enum pwm_polarity polarity; 41}; 42 43enum { 44 PWMF_REQUESTED = 0, 45 PWMF_EXPORTED = 1, 46}; 47 48/* 49 * struct pwm_state - state of a PWM channel 50 * @period: PWM period (in nanoseconds) 51 * @duty_cycle: PWM duty cycle (in nanoseconds) 52 * @polarity: PWM polarity 53 * @enabled: PWM enabled status 54 * @usage_power: If set, the PWM driver is only required to maintain the power 55 * output but has more freedom regarding signal form. 56 * If supported, the signal can be optimized, for example to 57 * improve EMI by phase shifting individual channels. 58 */ 59struct pwm_state { 60 u64 period; 61 u64 duty_cycle; 62 enum pwm_polarity polarity; 63 bool enabled; 64 bool usage_power; 65}; 66 67/** 68 * struct pwm_device - PWM channel object 69 * @label: name of the PWM device 70 * @flags: flags associated with the PWM device 71 * @hwpwm: per-chip relative index of the PWM device 72 * @chip: PWM chip providing this PWM device 73 * @args: PWM arguments 74 * @state: last applied state 75 * @last: last implemented state (for PWM_DEBUG) 76 */ 77struct pwm_device { 78 const char *label; 79 unsigned long flags; 80 unsigned int hwpwm; 81 struct pwm_chip *chip; 82 83 struct pwm_args args; 84 struct pwm_state state; 85 struct pwm_state last; 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 * The returned PWM state represents the state that was applied by a previous call to 94 * pwm_apply_might_sleep(). Drivers may have to slightly tweak that state before programming it to 95 * hardware. If pwm_apply_might_sleep() was never called, this returns either the current hardware 96 * state (if supported) or the default settings. 97 */ 98static inline void pwm_get_state(const struct pwm_device *pwm, 99 struct pwm_state *state) 100{ 101 *state = pwm->state; 102} 103 104static inline bool pwm_is_enabled(const struct pwm_device *pwm) 105{ 106 struct pwm_state state; 107 108 pwm_get_state(pwm, &state); 109 110 return state.enabled; 111} 112 113static inline u64 pwm_get_period(const struct pwm_device *pwm) 114{ 115 struct pwm_state state; 116 117 pwm_get_state(pwm, &state); 118 119 return state.period; 120} 121 122static inline u64 pwm_get_duty_cycle(const struct pwm_device *pwm) 123{ 124 struct pwm_state state; 125 126 pwm_get_state(pwm, &state); 127 128 return state.duty_cycle; 129} 130 131static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) 132{ 133 struct pwm_state state; 134 135 pwm_get_state(pwm, &state); 136 137 return state.polarity; 138} 139 140static inline void pwm_get_args(const struct pwm_device *pwm, 141 struct pwm_args *args) 142{ 143 *args = pwm->args; 144} 145 146/** 147 * pwm_init_state() - prepare a new state to be applied with pwm_apply_might_sleep() 148 * @pwm: PWM device 149 * @state: state to fill with the prepared PWM state 150 * 151 * This functions prepares a state that can later be tweaked and applied 152 * to the PWM device with pwm_apply_might_sleep(). This is a convenient function 153 * that first retrieves the current PWM state and the replaces the period 154 * and polarity fields with the reference values defined in pwm->args. 155 * Once the function returns, you can adjust the ->enabled and ->duty_cycle 156 * fields according to your needs before calling pwm_apply_might_sleep(). 157 * 158 * ->duty_cycle is initially set to zero to avoid cases where the current 159 * ->duty_cycle value exceed the pwm_args->period one, which would trigger 160 * an error if the user calls pwm_apply_might_sleep() without adjusting ->duty_cycle 161 * first. 162 */ 163static inline void pwm_init_state(const struct pwm_device *pwm, 164 struct pwm_state *state) 165{ 166 struct pwm_args args; 167 168 /* First get the current state. */ 169 pwm_get_state(pwm, state); 170 171 /* Then fill it with the reference config */ 172 pwm_get_args(pwm, &args); 173 174 state->period = args.period; 175 state->polarity = args.polarity; 176 state->duty_cycle = 0; 177 state->usage_power = false; 178} 179 180/** 181 * pwm_get_relative_duty_cycle() - Get a relative duty cycle value 182 * @state: PWM state to extract the duty cycle from 183 * @scale: target scale of the relative duty cycle 184 * 185 * This functions converts the absolute duty cycle stored in @state (expressed 186 * in nanosecond) into a value relative to the period. 187 * 188 * For example if you want to get the duty_cycle expressed in percent, call: 189 * 190 * pwm_get_state(pwm, &state); 191 * duty = pwm_get_relative_duty_cycle(&state, 100); 192 */ 193static inline unsigned int 194pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) 195{ 196 if (!state->period) 197 return 0; 198 199 return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale, 200 state->period); 201} 202 203/** 204 * pwm_set_relative_duty_cycle() - Set a relative duty cycle value 205 * @state: PWM state to fill 206 * @duty_cycle: relative duty cycle value 207 * @scale: scale in which @duty_cycle is expressed 208 * 209 * This functions converts a relative into an absolute duty cycle (expressed 210 * in nanoseconds), and puts the result in state->duty_cycle. 211 * 212 * For example if you want to configure a 50% duty cycle, call: 213 * 214 * pwm_init_state(pwm, &state); 215 * pwm_set_relative_duty_cycle(&state, 50, 100); 216 * pwm_apply_might_sleep(pwm, &state); 217 * 218 * This functions returns -EINVAL if @duty_cycle and/or @scale are 219 * inconsistent (@scale == 0 or @duty_cycle > @scale). 220 */ 221static inline int 222pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, 223 unsigned int scale) 224{ 225 if (!scale || duty_cycle > scale) 226 return -EINVAL; 227 228 state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle * 229 state->period, 230 scale); 231 232 return 0; 233} 234 235/** 236 * struct pwm_capture - PWM capture data 237 * @period: period of the PWM signal (in nanoseconds) 238 * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) 239 */ 240struct pwm_capture { 241 unsigned int period; 242 unsigned int duty_cycle; 243}; 244 245/** 246 * struct pwm_ops - PWM controller operations 247 * @request: optional hook for requesting a PWM 248 * @free: optional hook for freeing a PWM 249 * @capture: capture and report PWM signal 250 * @apply: atomically apply a new PWM config 251 * @get_state: get the current PWM state. This function is only 252 * called once per PWM device when the PWM chip is 253 * registered. 254 */ 255struct pwm_ops { 256 int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); 257 void (*free)(struct pwm_chip *chip, struct pwm_device *pwm); 258 int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm, 259 struct pwm_capture *result, unsigned long timeout); 260 int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, 261 const struct pwm_state *state); 262 int (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, 263 struct pwm_state *state); 264}; 265 266/** 267 * struct pwm_chip - abstract a PWM controller 268 * @dev: device providing the PWMs 269 * @ops: callbacks for this PWM controller 270 * @owner: module providing this chip 271 * @id: unique number of this PWM chip 272 * @npwm: number of PWMs controlled by this chip 273 * @of_xlate: request a PWM device given a device tree PWM specifier 274 * @atomic: can the driver's ->apply() be called in atomic context 275 * @driver_data: Private pointer for driver specific info 276 * @pwms: array of PWM devices allocated by the framework 277 */ 278struct pwm_chip { 279 struct device *dev; 280 const struct pwm_ops *ops; 281 struct module *owner; 282 unsigned int id; 283 unsigned int npwm; 284 285 struct pwm_device * (*of_xlate)(struct pwm_chip *chip, 286 const struct of_phandle_args *args); 287 bool atomic; 288 289 /* only used internally by the PWM framework */ 290 void *driver_data; 291 struct pwm_device *pwms; 292}; 293 294static inline struct device *pwmchip_parent(const struct pwm_chip *chip) 295{ 296 return chip->dev; 297} 298 299static inline void *pwmchip_get_drvdata(struct pwm_chip *chip) 300{ 301 /* 302 * After pwm_chip got a dedicated struct device, this can be replaced by 303 * dev_get_drvdata(&chip->dev); 304 */ 305 return chip->driver_data; 306} 307 308static inline void pwmchip_set_drvdata(struct pwm_chip *chip, void *data) 309{ 310 /* 311 * After pwm_chip got a dedicated struct device, this can be replaced by 312 * dev_set_drvdata(&chip->dev, data); 313 */ 314 chip->driver_data = data; 315} 316 317#if IS_ENABLED(CONFIG_PWM) 318/* PWM user APIs */ 319int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state); 320int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state); 321int pwm_adjust_config(struct pwm_device *pwm); 322 323/** 324 * pwm_config() - change a PWM device configuration 325 * @pwm: PWM device 326 * @duty_ns: "on" time (in nanoseconds) 327 * @period_ns: duration (in nanoseconds) of one cycle 328 * 329 * Returns: 0 on success or a negative error code on failure. 330 */ 331static inline int pwm_config(struct pwm_device *pwm, int duty_ns, 332 int period_ns) 333{ 334 struct pwm_state state; 335 336 if (!pwm) 337 return -EINVAL; 338 339 if (duty_ns < 0 || period_ns < 0) 340 return -EINVAL; 341 342 pwm_get_state(pwm, &state); 343 if (state.duty_cycle == duty_ns && state.period == period_ns) 344 return 0; 345 346 state.duty_cycle = duty_ns; 347 state.period = period_ns; 348 return pwm_apply_might_sleep(pwm, &state); 349} 350 351/** 352 * pwm_enable() - start a PWM output toggling 353 * @pwm: PWM device 354 * 355 * Returns: 0 on success or a negative error code on failure. 356 */ 357static inline int pwm_enable(struct pwm_device *pwm) 358{ 359 struct pwm_state state; 360 361 if (!pwm) 362 return -EINVAL; 363 364 pwm_get_state(pwm, &state); 365 if (state.enabled) 366 return 0; 367 368 state.enabled = true; 369 return pwm_apply_might_sleep(pwm, &state); 370} 371 372/** 373 * pwm_disable() - stop a PWM output toggling 374 * @pwm: PWM device 375 */ 376static inline void pwm_disable(struct pwm_device *pwm) 377{ 378 struct pwm_state state; 379 380 if (!pwm) 381 return; 382 383 pwm_get_state(pwm, &state); 384 if (!state.enabled) 385 return; 386 387 state.enabled = false; 388 pwm_apply_might_sleep(pwm, &state); 389} 390 391/** 392 * pwm_might_sleep() - is pwm_apply_atomic() supported? 393 * @pwm: PWM device 394 * 395 * Returns: false if pwm_apply_atomic() can be called from atomic context. 396 */ 397static inline bool pwm_might_sleep(struct pwm_device *pwm) 398{ 399 return !pwm->chip->atomic; 400} 401 402/* PWM provider APIs */ 403int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, 404 unsigned long timeout); 405 406void pwmchip_put(struct pwm_chip *chip); 407struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv); 408struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv); 409 410int __pwmchip_add(struct pwm_chip *chip, struct module *owner); 411#define pwmchip_add(chip) __pwmchip_add(chip, THIS_MODULE) 412void pwmchip_remove(struct pwm_chip *chip); 413 414int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner); 415#define devm_pwmchip_add(dev, chip) __devm_pwmchip_add(dev, chip, THIS_MODULE) 416 417struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, 418 unsigned int index, 419 const char *label); 420 421struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *chip, 422 const struct of_phandle_args *args); 423struct pwm_device *of_pwm_single_xlate(struct pwm_chip *chip, 424 const struct of_phandle_args *args); 425 426struct pwm_device *pwm_get(struct device *dev, const char *con_id); 427void pwm_put(struct pwm_device *pwm); 428 429struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id); 430struct pwm_device *devm_fwnode_pwm_get(struct device *dev, 431 struct fwnode_handle *fwnode, 432 const char *con_id); 433#else 434static inline bool pwm_might_sleep(struct pwm_device *pwm) 435{ 436 return true; 437} 438 439static inline int pwm_apply_might_sleep(struct pwm_device *pwm, 440 const struct pwm_state *state) 441{ 442 might_sleep(); 443 return -EOPNOTSUPP; 444} 445 446static inline int pwm_apply_atomic(struct pwm_device *pwm, 447 const struct pwm_state *state) 448{ 449 return -EOPNOTSUPP; 450} 451 452static inline int pwm_adjust_config(struct pwm_device *pwm) 453{ 454 return -EOPNOTSUPP; 455} 456 457static inline int pwm_config(struct pwm_device *pwm, int duty_ns, 458 int period_ns) 459{ 460 might_sleep(); 461 return -EINVAL; 462} 463 464static inline int pwm_enable(struct pwm_device *pwm) 465{ 466 might_sleep(); 467 return -EINVAL; 468} 469 470static inline void pwm_disable(struct pwm_device *pwm) 471{ 472 might_sleep(); 473} 474 475static inline int pwm_capture(struct pwm_device *pwm, 476 struct pwm_capture *result, 477 unsigned long timeout) 478{ 479 return -EINVAL; 480} 481 482static inline void pwmchip_put(struct pwm_chip *chip) 483{ 484} 485 486static inline struct pwm_chip *pwmchip_alloc(struct device *parent, 487 unsigned int npwm, 488 size_t sizeof_priv) 489{ 490 return ERR_PTR(-EINVAL); 491} 492 493static inline struct pwm_chip *devm_pwmchip_alloc(struct device *parent, 494 unsigned int npwm, 495 size_t sizeof_priv) 496{ 497 return pwmchip_alloc(parent, npwm, sizeof_priv); 498} 499 500static inline int pwmchip_add(struct pwm_chip *chip) 501{ 502 return -EINVAL; 503} 504 505static inline int pwmchip_remove(struct pwm_chip *chip) 506{ 507 return -EINVAL; 508} 509 510static inline int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip) 511{ 512 return -EINVAL; 513} 514 515static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, 516 unsigned int index, 517 const char *label) 518{ 519 might_sleep(); 520 return ERR_PTR(-ENODEV); 521} 522 523static inline struct pwm_device *pwm_get(struct device *dev, 524 const char *consumer) 525{ 526 might_sleep(); 527 return ERR_PTR(-ENODEV); 528} 529 530static inline void pwm_put(struct pwm_device *pwm) 531{ 532 might_sleep(); 533} 534 535static inline struct pwm_device *devm_pwm_get(struct device *dev, 536 const char *consumer) 537{ 538 might_sleep(); 539 return ERR_PTR(-ENODEV); 540} 541 542static inline struct pwm_device * 543devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, 544 const char *con_id) 545{ 546 might_sleep(); 547 return ERR_PTR(-ENODEV); 548} 549#endif 550 551static inline void pwm_apply_args(struct pwm_device *pwm) 552{ 553 struct pwm_state state = { }; 554 555 /* 556 * PWM users calling pwm_apply_args() expect to have a fresh config 557 * where the polarity and period are set according to pwm_args info. 558 * The problem is, polarity can only be changed when the PWM is 559 * disabled. 560 * 561 * PWM drivers supporting hardware readout may declare the PWM device 562 * as enabled, and prevent polarity setting, which changes from the 563 * existing behavior, where all PWM devices are declared as disabled 564 * at startup (even if they are actually enabled), thus authorizing 565 * polarity setting. 566 * 567 * To fulfill this requirement, we apply a new state which disables 568 * the PWM device and set the reference period and polarity config. 569 * 570 * Note that PWM users requiring a smooth handover between the 571 * bootloader and the kernel (like critical regulators controlled by 572 * PWM devices) will have to switch to the atomic API and avoid calling 573 * pwm_apply_args(). 574 */ 575 576 state.enabled = false; 577 state.polarity = pwm->args.polarity; 578 state.period = pwm->args.period; 579 state.usage_power = false; 580 581 pwm_apply_might_sleep(pwm, &state); 582} 583 584/* only for backwards-compatibility, new code should not use this */ 585static inline int pwm_apply_state(struct pwm_device *pwm, 586 const struct pwm_state *state) 587{ 588 return pwm_apply_might_sleep(pwm, state); 589} 590 591struct pwm_lookup { 592 struct list_head list; 593 const char *provider; 594 unsigned int index; 595 const char *dev_id; 596 const char *con_id; 597 unsigned int period; 598 enum pwm_polarity polarity; 599 const char *module; /* optional, may be NULL */ 600}; 601 602#define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ 603 _period, _polarity, _module) \ 604 { \ 605 .provider = _provider, \ 606 .index = _index, \ 607 .dev_id = _dev_id, \ 608 .con_id = _con_id, \ 609 .period = _period, \ 610 .polarity = _polarity, \ 611 .module = _module, \ 612 } 613 614#define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ 615 PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ 616 _polarity, NULL) 617 618#if IS_ENABLED(CONFIG_PWM) 619void pwm_add_table(struct pwm_lookup *table, size_t num); 620void pwm_remove_table(struct pwm_lookup *table, size_t num); 621#else 622static inline void pwm_add_table(struct pwm_lookup *table, size_t num) 623{ 624} 625 626static inline void pwm_remove_table(struct pwm_lookup *table, size_t num) 627{ 628} 629#endif 630 631#ifdef CONFIG_PWM_SYSFS 632void pwmchip_sysfs_export(struct pwm_chip *chip); 633void pwmchip_sysfs_unexport(struct pwm_chip *chip); 634#else 635static inline void pwmchip_sysfs_export(struct pwm_chip *chip) 636{ 637} 638 639static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip) 640{ 641} 642#endif /* CONFIG_PWM_SYSFS */ 643 644#endif /* __LINUX_PWM_H */ 645