1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) STMicroelectronics 2016 4 * 5 * Author: Gerald Baeza <gerald.baeza@st.com> 6 * 7 * Inspired by timer-stm32.c from Maxime Coquelin 8 * pwm-atmel.c from Bo Shen 9 */ 10 11 #include <linux/bitfield.h> 12 #include <linux/mfd/stm32-timers.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/pinctrl/consumer.h> 16 #include <linux/platform_device.h> 17 #include <linux/pwm.h> 18 19 #define CCMR_CHANNEL_SHIFT 8 20 #define CCMR_CHANNEL_MASK 0xFF 21 #define MAX_BREAKINPUT 2 22 23 struct stm32_breakinput { 24 u32 index; 25 u32 level; 26 u32 filter; 27 }; 28 29 struct stm32_pwm { 30 struct pwm_chip chip; 31 struct mutex lock; /* protect pwm config/enable */ 32 struct clk *clk; 33 struct regmap *regmap; 34 u32 max_arr; 35 bool have_complementary_output; 36 struct stm32_breakinput breakinputs[MAX_BREAKINPUT]; 37 unsigned int num_breakinputs; 38 u32 capture[4] ____cacheline_aligned; /* DMA'able buffer */ 39 }; 40 41 static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip) 42 { 43 return container_of(chip, struct stm32_pwm, chip); 44 } 45 46 static u32 active_channels(struct stm32_pwm *dev) 47 { 48 u32 ccer; 49 50 regmap_read(dev->regmap, TIM_CCER, &ccer); 51 52 return ccer & TIM_CCER_CCXE; 53 } 54 55 static int write_ccrx(struct stm32_pwm *dev, int ch, u32 value) 56 { 57 switch (ch) { 58 case 0: 59 return regmap_write(dev->regmap, TIM_CCR1, value); 60 case 1: 61 return regmap_write(dev->regmap, TIM_CCR2, value); 62 case 2: 63 return regmap_write(dev->regmap, TIM_CCR3, value); 64 case 3: 65 return regmap_write(dev->regmap, TIM_CCR4, value); 66 } 67 return -EINVAL; 68 } 69 70 #define TIM_CCER_CC12P (TIM_CCER_CC1P | TIM_CCER_CC2P) 71 #define TIM_CCER_CC12E (TIM_CCER_CC1E | TIM_CCER_CC2E) 72 #define TIM_CCER_CC34P (TIM_CCER_CC3P | TIM_CCER_CC4P) 73 #define TIM_CCER_CC34E (TIM_CCER_CC3E | TIM_CCER_CC4E) 74 75 /* 76 * Capture using PWM input mode: 77 * ___ ___ 78 * TI[1, 2, 3 or 4]: ........._| |________| 79 * ^0 ^1 ^2 80 * . . . 81 * . . XXXXX 82 * . . XXXXX | 83 * . XXXXX . | 84 * XXXXX . . | 85 * COUNTER: ______XXXXX . . . |_XXX 86 * start^ . . . ^stop 87 * . . . . 88 * v v . v 89 * v 90 * CCR1/CCR3: tx..........t0...........t2 91 * CCR2/CCR4: tx..............t1......... 92 * 93 * DMA burst transfer: | | 94 * v v 95 * DMA buffer: { t0, tx } { t2, t1 } 96 * DMA done: ^ 97 * 98 * 0: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3 99 * + DMA transfer CCR[1/3] & CCR[2/4] values (t0, tx: doesn't care) 100 * 1: IC2/4 snapchot on falling edge: counter value -> CCR2/CCR4 101 * 2: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3 102 * + DMA transfer CCR[1/3] & CCR[2/4] values (t2, t1) 103 * 104 * DMA done, compute: 105 * - Period = t2 - t0 106 * - Duty cycle = t1 - t0 107 */ 108 static int stm32_pwm_raw_capture(struct stm32_pwm *priv, struct pwm_device *pwm, 109 unsigned long tmo_ms, u32 *raw_prd, 110 u32 *raw_dty) 111 { 112 struct device *parent = priv->chip.dev->parent; 113 enum stm32_timers_dmas dma_id; 114 u32 ccen, ccr; 115 int ret; 116 117 /* Ensure registers have been updated, enable counter and capture */ 118 regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG); 119 regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN); 120 121 /* Use cc1 or cc3 DMA resp for PWM input channels 1 & 2 or 3 & 4 */ 122 dma_id = pwm->hwpwm < 2 ? STM32_TIMERS_DMA_CH1 : STM32_TIMERS_DMA_CH3; 123 ccen = pwm->hwpwm < 2 ? TIM_CCER_CC12E : TIM_CCER_CC34E; 124 ccr = pwm->hwpwm < 2 ? TIM_CCR1 : TIM_CCR3; 125 regmap_set_bits(priv->regmap, TIM_CCER, ccen); 126 127 /* 128 * Timer DMA burst mode. Request 2 registers, 2 bursts, to get both 129 * CCR1 & CCR2 (or CCR3 & CCR4) on each capture event. 130 * We'll get two capture snapchots: { CCR1, CCR2 }, { CCR1, CCR2 } 131 * or { CCR3, CCR4 }, { CCR3, CCR4 } 132 */ 133 ret = stm32_timers_dma_burst_read(parent, priv->capture, dma_id, ccr, 2, 134 2, tmo_ms); 135 if (ret) 136 goto stop; 137 138 /* Period: t2 - t0 (take care of counter overflow) */ 139 if (priv->capture[0] <= priv->capture[2]) 140 *raw_prd = priv->capture[2] - priv->capture[0]; 141 else 142 *raw_prd = priv->max_arr - priv->capture[0] + priv->capture[2]; 143 144 /* Duty cycle capture requires at least two capture units */ 145 if (pwm->chip->npwm < 2) 146 *raw_dty = 0; 147 else if (priv->capture[0] <= priv->capture[3]) 148 *raw_dty = priv->capture[3] - priv->capture[0]; 149 else 150 *raw_dty = priv->max_arr - priv->capture[0] + priv->capture[3]; 151 152 if (*raw_dty > *raw_prd) { 153 /* 154 * Race beetween PWM input and DMA: it may happen 155 * falling edge triggers new capture on TI2/4 before DMA 156 * had a chance to read CCR2/4. It means capture[1] 157 * contains period + duty_cycle. So, subtract period. 158 */ 159 *raw_dty -= *raw_prd; 160 } 161 162 stop: 163 regmap_clear_bits(priv->regmap, TIM_CCER, ccen); 164 regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN); 165 166 return ret; 167 } 168 169 static int stm32_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm, 170 struct pwm_capture *result, unsigned long tmo_ms) 171 { 172 struct stm32_pwm *priv = to_stm32_pwm_dev(chip); 173 unsigned long long prd, div, dty; 174 unsigned long rate; 175 unsigned int psc = 0, icpsc, scale; 176 u32 raw_prd = 0, raw_dty = 0; 177 int ret = 0; 178 179 mutex_lock(&priv->lock); 180 181 if (active_channels(priv)) { 182 ret = -EBUSY; 183 goto unlock; 184 } 185 186 ret = clk_enable(priv->clk); 187 if (ret) { 188 dev_err(priv->chip.dev, "failed to enable counter clock\n"); 189 goto unlock; 190 } 191 192 rate = clk_get_rate(priv->clk); 193 if (!rate) { 194 ret = -EINVAL; 195 goto clk_dis; 196 } 197 198 /* prescaler: fit timeout window provided by upper layer */ 199 div = (unsigned long long)rate * (unsigned long long)tmo_ms; 200 do_div(div, MSEC_PER_SEC); 201 prd = div; 202 while ((div > priv->max_arr) && (psc < MAX_TIM_PSC)) { 203 psc++; 204 div = prd; 205 do_div(div, psc + 1); 206 } 207 regmap_write(priv->regmap, TIM_ARR, priv->max_arr); 208 regmap_write(priv->regmap, TIM_PSC, psc); 209 210 /* Reset input selector to its default input and disable slave mode */ 211 regmap_write(priv->regmap, TIM_TISEL, 0x0); 212 regmap_write(priv->regmap, TIM_SMCR, 0x0); 213 214 /* Map TI1 or TI2 PWM input to IC1 & IC2 (or TI3/4 to IC3 & IC4) */ 215 regmap_update_bits(priv->regmap, 216 pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2, 217 TIM_CCMR_CC1S | TIM_CCMR_CC2S, pwm->hwpwm & 0x1 ? 218 TIM_CCMR_CC1S_TI2 | TIM_CCMR_CC2S_TI2 : 219 TIM_CCMR_CC1S_TI1 | TIM_CCMR_CC2S_TI1); 220 221 /* Capture period on IC1/3 rising edge, duty cycle on IC2/4 falling. */ 222 regmap_update_bits(priv->regmap, TIM_CCER, pwm->hwpwm < 2 ? 223 TIM_CCER_CC12P : TIM_CCER_CC34P, pwm->hwpwm < 2 ? 224 TIM_CCER_CC2P : TIM_CCER_CC4P); 225 226 ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd, &raw_dty); 227 if (ret) 228 goto stop; 229 230 /* 231 * Got a capture. Try to improve accuracy at high rates: 232 * - decrease counter clock prescaler, scale up to max rate. 233 * - use input prescaler, capture once every /2 /4 or /8 edges. 234 */ 235 if (raw_prd) { 236 u32 max_arr = priv->max_arr - 0x1000; /* arbitrary margin */ 237 238 scale = max_arr / min(max_arr, raw_prd); 239 } else { 240 scale = priv->max_arr; /* bellow resolution, use max scale */ 241 } 242 243 if (psc && scale > 1) { 244 /* 2nd measure with new scale */ 245 psc /= scale; 246 regmap_write(priv->regmap, TIM_PSC, psc); 247 ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd, 248 &raw_dty); 249 if (ret) 250 goto stop; 251 } 252 253 /* Compute intermediate period not to exceed timeout at low rates */ 254 prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC; 255 do_div(prd, rate); 256 257 for (icpsc = 0; icpsc < MAX_TIM_ICPSC ; icpsc++) { 258 /* input prescaler: also keep arbitrary margin */ 259 if (raw_prd >= (priv->max_arr - 0x1000) >> (icpsc + 1)) 260 break; 261 if (prd >= (tmo_ms * NSEC_PER_MSEC) >> (icpsc + 2)) 262 break; 263 } 264 265 if (!icpsc) 266 goto done; 267 268 /* Last chance to improve period accuracy, using input prescaler */ 269 regmap_update_bits(priv->regmap, 270 pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2, 271 TIM_CCMR_IC1PSC | TIM_CCMR_IC2PSC, 272 FIELD_PREP(TIM_CCMR_IC1PSC, icpsc) | 273 FIELD_PREP(TIM_CCMR_IC2PSC, icpsc)); 274 275 ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd, &raw_dty); 276 if (ret) 277 goto stop; 278 279 if (raw_dty >= (raw_prd >> icpsc)) { 280 /* 281 * We may fall here using input prescaler, when input 282 * capture starts on high side (before falling edge). 283 * Example with icpsc to capture on each 4 events: 284 * 285 * start 1st capture 2nd capture 286 * v v v 287 * ___ _____ _____ _____ _____ ____ 288 * TI1..4 |__| |__| |__| |__| |__| 289 * v v . . . . . v v 290 * icpsc1/3: . 0 . 1 . 2 . 3 . 0 291 * icpsc2/4: 0 1 2 3 0 292 * v v v v 293 * CCR1/3 ......t0..............................t2 294 * CCR2/4 ..t1..............................t1'... 295 * . . . 296 * Capture0: .<----------------------------->. 297 * Capture1: .<-------------------------->. . 298 * . . . 299 * Period: .<------> . . 300 * Low side: .<>. 301 * 302 * Result: 303 * - Period = Capture0 / icpsc 304 * - Duty = Period - Low side = Period - (Capture0 - Capture1) 305 */ 306 raw_dty = (raw_prd >> icpsc) - (raw_prd - raw_dty); 307 } 308 309 done: 310 prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC; 311 result->period = DIV_ROUND_UP_ULL(prd, rate << icpsc); 312 dty = (unsigned long long)raw_dty * (psc + 1) * NSEC_PER_SEC; 313 result->duty_cycle = DIV_ROUND_UP_ULL(dty, rate); 314 stop: 315 regmap_write(priv->regmap, TIM_CCER, 0); 316 regmap_write(priv->regmap, pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2, 0); 317 regmap_write(priv->regmap, TIM_PSC, 0); 318 clk_dis: 319 clk_disable(priv->clk); 320 unlock: 321 mutex_unlock(&priv->lock); 322 323 return ret; 324 } 325 326 static int stm32_pwm_config(struct stm32_pwm *priv, int ch, 327 int duty_ns, int period_ns) 328 { 329 unsigned long long prd, div, dty; 330 unsigned int prescaler = 0; 331 u32 ccmr, mask, shift; 332 333 /* Period and prescaler values depends on clock rate */ 334 div = (unsigned long long)clk_get_rate(priv->clk) * period_ns; 335 336 do_div(div, NSEC_PER_SEC); 337 prd = div; 338 339 while (div > priv->max_arr) { 340 prescaler++; 341 div = prd; 342 do_div(div, prescaler + 1); 343 } 344 345 prd = div; 346 347 if (prescaler > MAX_TIM_PSC) 348 return -EINVAL; 349 350 /* 351 * All channels share the same prescaler and counter so when two 352 * channels are active at the same time we can't change them 353 */ 354 if (active_channels(priv) & ~(1 << ch * 4)) { 355 u32 psc, arr; 356 357 regmap_read(priv->regmap, TIM_PSC, &psc); 358 regmap_read(priv->regmap, TIM_ARR, &arr); 359 360 if ((psc != prescaler) || (arr != prd - 1)) 361 return -EBUSY; 362 } 363 364 regmap_write(priv->regmap, TIM_PSC, prescaler); 365 regmap_write(priv->regmap, TIM_ARR, prd - 1); 366 regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE); 367 368 /* Calculate the duty cycles */ 369 dty = prd * duty_ns; 370 do_div(dty, period_ns); 371 372 write_ccrx(priv, ch, dty); 373 374 /* Configure output mode */ 375 shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT; 376 ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift; 377 mask = CCMR_CHANNEL_MASK << shift; 378 379 if (ch < 2) 380 regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr); 381 else 382 regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr); 383 384 regmap_set_bits(priv->regmap, TIM_BDTR, TIM_BDTR_MOE); 385 386 return 0; 387 } 388 389 static int stm32_pwm_set_polarity(struct stm32_pwm *priv, int ch, 390 enum pwm_polarity polarity) 391 { 392 u32 mask; 393 394 mask = TIM_CCER_CC1P << (ch * 4); 395 if (priv->have_complementary_output) 396 mask |= TIM_CCER_CC1NP << (ch * 4); 397 398 regmap_update_bits(priv->regmap, TIM_CCER, mask, 399 polarity == PWM_POLARITY_NORMAL ? 0 : mask); 400 401 return 0; 402 } 403 404 static int stm32_pwm_enable(struct stm32_pwm *priv, int ch) 405 { 406 u32 mask; 407 int ret; 408 409 ret = clk_enable(priv->clk); 410 if (ret) 411 return ret; 412 413 /* Enable channel */ 414 mask = TIM_CCER_CC1E << (ch * 4); 415 if (priv->have_complementary_output) 416 mask |= TIM_CCER_CC1NE << (ch * 4); 417 418 regmap_set_bits(priv->regmap, TIM_CCER, mask); 419 420 /* Make sure that registers are updated */ 421 regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG); 422 423 /* Enable controller */ 424 regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN); 425 426 return 0; 427 } 428 429 static void stm32_pwm_disable(struct stm32_pwm *priv, int ch) 430 { 431 u32 mask; 432 433 /* Disable channel */ 434 mask = TIM_CCER_CC1E << (ch * 4); 435 if (priv->have_complementary_output) 436 mask |= TIM_CCER_CC1NE << (ch * 4); 437 438 regmap_clear_bits(priv->regmap, TIM_CCER, mask); 439 440 /* When all channels are disabled, we can disable the controller */ 441 if (!active_channels(priv)) 442 regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN); 443 444 clk_disable(priv->clk); 445 } 446 447 static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 448 const struct pwm_state *state) 449 { 450 bool enabled; 451 struct stm32_pwm *priv = to_stm32_pwm_dev(chip); 452 int ret; 453 454 enabled = pwm->state.enabled; 455 456 if (enabled && !state->enabled) { 457 stm32_pwm_disable(priv, pwm->hwpwm); 458 return 0; 459 } 460 461 if (state->polarity != pwm->state.polarity) 462 stm32_pwm_set_polarity(priv, pwm->hwpwm, state->polarity); 463 464 ret = stm32_pwm_config(priv, pwm->hwpwm, 465 state->duty_cycle, state->period); 466 if (ret) 467 return ret; 468 469 if (!enabled && state->enabled) 470 ret = stm32_pwm_enable(priv, pwm->hwpwm); 471 472 return ret; 473 } 474 475 static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm, 476 const struct pwm_state *state) 477 { 478 struct stm32_pwm *priv = to_stm32_pwm_dev(chip); 479 int ret; 480 481 /* protect common prescaler for all active channels */ 482 mutex_lock(&priv->lock); 483 ret = stm32_pwm_apply(chip, pwm, state); 484 mutex_unlock(&priv->lock); 485 486 return ret; 487 } 488 489 static const struct pwm_ops stm32pwm_ops = { 490 .owner = THIS_MODULE, 491 .apply = stm32_pwm_apply_locked, 492 .capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL, 493 }; 494 495 static int stm32_pwm_set_breakinput(struct stm32_pwm *priv, 496 const struct stm32_breakinput *bi) 497 { 498 u32 shift = TIM_BDTR_BKF_SHIFT(bi->index); 499 u32 bke = TIM_BDTR_BKE(bi->index); 500 u32 bkp = TIM_BDTR_BKP(bi->index); 501 u32 bkf = TIM_BDTR_BKF(bi->index); 502 u32 mask = bkf | bkp | bke; 503 u32 bdtr; 504 505 bdtr = (bi->filter & TIM_BDTR_BKF_MASK) << shift | bke; 506 507 if (bi->level) 508 bdtr |= bkp; 509 510 regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr); 511 512 regmap_read(priv->regmap, TIM_BDTR, &bdtr); 513 514 return (bdtr & bke) ? 0 : -EINVAL; 515 } 516 517 static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv) 518 { 519 unsigned int i; 520 int ret; 521 522 for (i = 0; i < priv->num_breakinputs; i++) { 523 ret = stm32_pwm_set_breakinput(priv, &priv->breakinputs[i]); 524 if (ret < 0) 525 return ret; 526 } 527 528 return 0; 529 } 530 531 static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv, 532 struct device_node *np) 533 { 534 int nb, ret, array_size; 535 unsigned int i; 536 537 nb = of_property_count_elems_of_size(np, "st,breakinput", 538 sizeof(struct stm32_breakinput)); 539 540 /* 541 * Because "st,breakinput" parameter is optional do not make probe 542 * failed if it doesn't exist. 543 */ 544 if (nb <= 0) 545 return 0; 546 547 if (nb > MAX_BREAKINPUT) 548 return -EINVAL; 549 550 priv->num_breakinputs = nb; 551 array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32); 552 ret = of_property_read_u32_array(np, "st,breakinput", 553 (u32 *)priv->breakinputs, array_size); 554 if (ret) 555 return ret; 556 557 for (i = 0; i < priv->num_breakinputs; i++) { 558 if (priv->breakinputs[i].index > 1 || 559 priv->breakinputs[i].level > 1 || 560 priv->breakinputs[i].filter > 15) 561 return -EINVAL; 562 } 563 564 return stm32_pwm_apply_breakinputs(priv); 565 } 566 567 static void stm32_pwm_detect_complementary(struct stm32_pwm *priv) 568 { 569 u32 ccer; 570 571 /* 572 * If complementary bit doesn't exist writing 1 will have no 573 * effect so we can detect it. 574 */ 575 regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE); 576 regmap_read(priv->regmap, TIM_CCER, &ccer); 577 regmap_clear_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE); 578 579 priv->have_complementary_output = (ccer != 0); 580 } 581 582 static int stm32_pwm_detect_channels(struct stm32_pwm *priv) 583 { 584 u32 ccer; 585 int npwm = 0; 586 587 /* 588 * If channels enable bits don't exist writing 1 will have no 589 * effect so we can detect and count them. 590 */ 591 regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE); 592 regmap_read(priv->regmap, TIM_CCER, &ccer); 593 regmap_clear_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE); 594 595 if (ccer & TIM_CCER_CC1E) 596 npwm++; 597 598 if (ccer & TIM_CCER_CC2E) 599 npwm++; 600 601 if (ccer & TIM_CCER_CC3E) 602 npwm++; 603 604 if (ccer & TIM_CCER_CC4E) 605 npwm++; 606 607 return npwm; 608 } 609 610 static int stm32_pwm_probe(struct platform_device *pdev) 611 { 612 struct device *dev = &pdev->dev; 613 struct device_node *np = dev->of_node; 614 struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent); 615 struct stm32_pwm *priv; 616 int ret; 617 618 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 619 if (!priv) 620 return -ENOMEM; 621 622 mutex_init(&priv->lock); 623 priv->regmap = ddata->regmap; 624 priv->clk = ddata->clk; 625 priv->max_arr = ddata->max_arr; 626 627 if (!priv->regmap || !priv->clk) 628 return -EINVAL; 629 630 ret = stm32_pwm_probe_breakinputs(priv, np); 631 if (ret) 632 return ret; 633 634 stm32_pwm_detect_complementary(priv); 635 636 priv->chip.dev = dev; 637 priv->chip.ops = &stm32pwm_ops; 638 priv->chip.npwm = stm32_pwm_detect_channels(priv); 639 640 ret = devm_pwmchip_add(dev, &priv->chip); 641 if (ret < 0) 642 return ret; 643 644 platform_set_drvdata(pdev, priv); 645 646 return 0; 647 } 648 649 static int __maybe_unused stm32_pwm_suspend(struct device *dev) 650 { 651 struct stm32_pwm *priv = dev_get_drvdata(dev); 652 unsigned int i; 653 u32 ccer, mask; 654 655 /* Look for active channels */ 656 ccer = active_channels(priv); 657 658 for (i = 0; i < priv->chip.npwm; i++) { 659 mask = TIM_CCER_CC1E << (i * 4); 660 if (ccer & mask) { 661 dev_err(dev, "PWM %u still in use by consumer %s\n", 662 i, priv->chip.pwms[i].label); 663 return -EBUSY; 664 } 665 } 666 667 return pinctrl_pm_select_sleep_state(dev); 668 } 669 670 static int __maybe_unused stm32_pwm_resume(struct device *dev) 671 { 672 struct stm32_pwm *priv = dev_get_drvdata(dev); 673 int ret; 674 675 ret = pinctrl_pm_select_default_state(dev); 676 if (ret) 677 return ret; 678 679 /* restore breakinput registers that may have been lost in low power */ 680 return stm32_pwm_apply_breakinputs(priv); 681 } 682 683 static SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume); 684 685 static const struct of_device_id stm32_pwm_of_match[] = { 686 { .compatible = "st,stm32-pwm", }, 687 { /* end node */ }, 688 }; 689 MODULE_DEVICE_TABLE(of, stm32_pwm_of_match); 690 691 static struct platform_driver stm32_pwm_driver = { 692 .probe = stm32_pwm_probe, 693 .driver = { 694 .name = "stm32-pwm", 695 .of_match_table = stm32_pwm_of_match, 696 .pm = &stm32_pwm_pm_ops, 697 }, 698 }; 699 module_platform_driver(stm32_pwm_driver); 700 701 MODULE_ALIAS("platform:stm32-pwm"); 702 MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver"); 703 MODULE_LICENSE("GPL v2"); 704