drivers/pwm/pwm-stm32.c

   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_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
 119         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 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_update_bits(priv->regmap, TIM_CCER, ccen, 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_update_bits(priv->regmap, TIM_CCER, ccen, 0);
 164         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 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         /* Map TI1 or TI2 PWM input to IC1 & IC2 (or TI3/4 to IC3 & IC4) */
 211         regmap_update_bits(priv->regmap,
 212                            pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
 213                            TIM_CCMR_CC1S | TIM_CCMR_CC2S, pwm->hwpwm & 0x1 ?
 214                            TIM_CCMR_CC1S_TI2 | TIM_CCMR_CC2S_TI2 :
 215                            TIM_CCMR_CC1S_TI1 | TIM_CCMR_CC2S_TI1);
 216
 217         /* Capture period on IC1/3 rising edge, duty cycle on IC2/4 falling. */
 218         regmap_update_bits(priv->regmap, TIM_CCER, pwm->hwpwm < 2 ?
 219                            TIM_CCER_CC12P : TIM_CCER_CC34P, pwm->hwpwm < 2 ?
 220                            TIM_CCER_CC2P : TIM_CCER_CC4P);
 221
 222         ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd, &raw_dty);
 223         if (ret)
 224                 goto stop;
 225
 226         /*
 227          * Got a capture. Try to improve accuracy at high rates:
 228          * - decrease counter clock prescaler, scale up to max rate.
 229          * - use input prescaler, capture once every /2 /4 or /8 edges.
 230          */
 231         if (raw_prd) {
 232                 u32 max_arr = priv->max_arr - 0x1000; /* arbitrary margin */
 233
 234                 scale = max_arr / min(max_arr, raw_prd);
 235         } else {
 236                 scale = priv->max_arr; /* bellow resolution, use max scale */
 237         }
 238
 239         if (psc && scale > 1) {
 240                 /* 2nd measure with new scale */
 241                 psc /= scale;
 242                 regmap_write(priv->regmap, TIM_PSC, psc);
 243                 ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd,
 244                                             &raw_dty);
 245                 if (ret)
 246                         goto stop;
 247         }
 248
 249         /* Compute intermediate period not to exceed timeout at low rates */
 250         prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
 251         do_div(prd, rate);
 252
 253         for (icpsc = 0; icpsc < MAX_TIM_ICPSC ; icpsc++) {
 254                 /* input prescaler: also keep arbitrary margin */
 255                 if (raw_prd >= (priv->max_arr - 0x1000) >> (icpsc + 1))
 256                         break;
 257                 if (prd >= (tmo_ms * NSEC_PER_MSEC) >> (icpsc + 2))
 258                         break;
 259         }
 260
 261         if (!icpsc)
 262                 goto done;
 263
 264         /* Last chance to improve period accuracy, using input prescaler */
 265         regmap_update_bits(priv->regmap,
 266                            pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
 267                            TIM_CCMR_IC1PSC | TIM_CCMR_IC2PSC,
 268                            FIELD_PREP(TIM_CCMR_IC1PSC, icpsc) |
 269                            FIELD_PREP(TIM_CCMR_IC2PSC, icpsc));
 270
 271         ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd, &raw_dty);
 272         if (ret)
 273                 goto stop;
 274
 275         if (raw_dty >= (raw_prd >> icpsc)) {
 276                 /*
 277                  * We may fall here using input prescaler, when input
 278                  * capture starts on high side (before falling edge).
 279                  * Example with icpsc to capture on each 4 events:
 280                  *
 281                  *       start   1st capture                     2nd capture
 282                  *         v     v                               v
 283                  *         ___   _____   _____   _____   _____   ____
 284                  * TI1..4     |__|    |__|    |__|    |__|    |__|
 285                  *            v  v    .  .    .  .    .       v  v
 286                  * icpsc1/3:  .  0    .  1    .  2    .  3    .  0
 287                  * icpsc2/4:  0       1       2       3       0
 288                  *            v  v                            v  v
 289                  * CCR1/3  ......t0..............................t2
 290                  * CCR2/4  ..t1..............................t1'...
 291                  *               .                            .  .
 292                  * Capture0:     .<----------------------------->.
 293                  * Capture1:     .<-------------------------->.  .
 294                  *               .                            .  .
 295                  * Period:       .<------>                    .  .
 296                  * Low side:                                  .<>.
 297                  *
 298                  * Result:
 299                  * - Period = Capture0 / icpsc
 300                  * - Duty = Period - Low side = Period - (Capture0 - Capture1)
 301                  */
 302                 raw_dty = (raw_prd >> icpsc) - (raw_prd - raw_dty);
 303         }
 304
 305 done:
 306         prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
 307         result->period = DIV_ROUND_UP_ULL(prd, rate << icpsc);
 308         dty = (unsigned long long)raw_dty * (psc + 1) * NSEC_PER_SEC;
 309         result->duty_cycle = DIV_ROUND_UP_ULL(dty, rate);
 310 stop:
 311         regmap_write(priv->regmap, TIM_CCER, 0);
 312         regmap_write(priv->regmap, pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2, 0);
 313         regmap_write(priv->regmap, TIM_PSC, 0);
 314 clk_dis:
 315         clk_disable(priv->clk);
 316 unlock:
 317         mutex_unlock(&priv->lock);
 318
 319         return ret;
 320 }
 321
 322 static int stm32_pwm_config(struct stm32_pwm *priv, int ch,
 323                             int duty_ns, int period_ns)
 324 {
 325         unsigned long long prd, div, dty;
 326         unsigned int prescaler = 0;
 327         u32 ccmr, mask, shift;
 328
 329         /* Period and prescaler values depends on clock rate */
 330         div = (unsigned long long)clk_get_rate(priv->clk) * period_ns;
 331
 332         do_div(div, NSEC_PER_SEC);
 333         prd = div;
 334
 335         while (div > priv->max_arr) {
 336                 prescaler++;
 337                 div = prd;
 338                 do_div(div, prescaler + 1);
 339         }
 340
 341         prd = div;
 342
 343         if (prescaler > MAX_TIM_PSC)
 344                 return -EINVAL;
 345
 346         /*
 347          * All channels share the same prescaler and counter so when two
 348          * channels are active at the same time we can't change them
 349          */
 350         if (active_channels(priv) & ~(1 << ch * 4)) {
 351                 u32 psc, arr;
 352
 353                 regmap_read(priv->regmap, TIM_PSC, &psc);
 354                 regmap_read(priv->regmap, TIM_ARR, &arr);
 355
 356                 if ((psc != prescaler) || (arr != prd - 1))
 357                         return -EBUSY;
 358         }
 359
 360         regmap_write(priv->regmap, TIM_PSC, prescaler);
 361         regmap_write(priv->regmap, TIM_ARR, prd - 1);
 362         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
 363
 364         /* Calculate the duty cycles */
 365         dty = prd * duty_ns;
 366         do_div(dty, period_ns);
 367
 368         write_ccrx(priv, ch, dty);
 369
 370         /* Configure output mode */
 371         shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
 372         ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
 373         mask = CCMR_CHANNEL_MASK << shift;
 374
 375         if (ch < 2)
 376                 regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
 377         else
 378                 regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
 379
 380         regmap_update_bits(priv->regmap, TIM_BDTR,
 381                            TIM_BDTR_MOE | TIM_BDTR_AOE,
 382                            TIM_BDTR_MOE | TIM_BDTR_AOE);
 383
 384         return 0;
 385 }
 386
 387 static int stm32_pwm_set_polarity(struct stm32_pwm *priv, int ch,
 388                                   enum pwm_polarity polarity)
 389 {
 390         u32 mask;
 391
 392         mask = TIM_CCER_CC1P << (ch * 4);
 393         if (priv->have_complementary_output)
 394                 mask |= TIM_CCER_CC1NP << (ch * 4);
 395
 396         regmap_update_bits(priv->regmap, TIM_CCER, mask,
 397                            polarity == PWM_POLARITY_NORMAL ? 0 : mask);
 398
 399         return 0;
 400 }
 401
 402 static int stm32_pwm_enable(struct stm32_pwm *priv, int ch)
 403 {
 404         u32 mask;
 405         int ret;
 406
 407         ret = clk_enable(priv->clk);
 408         if (ret)
 409                 return ret;
 410
 411         /* Enable channel */
 412         mask = TIM_CCER_CC1E << (ch * 4);
 413         if (priv->have_complementary_output)
 414                 mask |= TIM_CCER_CC1NE << (ch * 4);
 415
 416         regmap_update_bits(priv->regmap, TIM_CCER, mask, mask);
 417
 418         /* Make sure that registers are updated */
 419         regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
 420
 421         /* Enable controller */
 422         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
 423
 424         return 0;
 425 }
 426
 427 static void stm32_pwm_disable(struct stm32_pwm *priv, int ch)
 428 {
 429         u32 mask;
 430
 431         /* Disable channel */
 432         mask = TIM_CCER_CC1E << (ch * 4);
 433         if (priv->have_complementary_output)
 434                 mask |= TIM_CCER_CC1NE << (ch * 4);
 435
 436         regmap_update_bits(priv->regmap, TIM_CCER, mask, 0);
 437
 438         /* When all channels are disabled, we can disable the controller */
 439         if (!active_channels(priv))
 440                 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 441
 442         clk_disable(priv->clk);
 443 }
 444
 445 static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 446                            const struct pwm_state *state)
 447 {
 448         bool enabled;
 449         struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
 450         int ret;
 451
 452         enabled = pwm->state.enabled;
 453
 454         if (enabled && !state->enabled) {
 455                 stm32_pwm_disable(priv, pwm->hwpwm);
 456                 return 0;
 457         }
 458
 459         if (state->polarity != pwm->state.polarity)
 460                 stm32_pwm_set_polarity(priv, pwm->hwpwm, state->polarity);
 461
 462         ret = stm32_pwm_config(priv, pwm->hwpwm,
 463                                state->duty_cycle, state->period);
 464         if (ret)
 465                 return ret;
 466
 467         if (!enabled && state->enabled)
 468                 ret = stm32_pwm_enable(priv, pwm->hwpwm);
 469
 470         return ret;
 471 }
 472
 473 static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm,
 474                                   const struct pwm_state *state)
 475 {
 476         struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
 477         int ret;
 478
 479         /* protect common prescaler for all active channels */
 480         mutex_lock(&priv->lock);
 481         ret = stm32_pwm_apply(chip, pwm, state);
 482         mutex_unlock(&priv->lock);
 483
 484         return ret;
 485 }
 486
 487 static const struct pwm_ops stm32pwm_ops = {
 488         .owner = THIS_MODULE,
 489         .apply = stm32_pwm_apply_locked,
 490         .capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL,
 491 };
 492
 493 static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
 494                                     const struct stm32_breakinput *bi)
 495 {
 496         u32 shift = TIM_BDTR_BKF_SHIFT(bi->index);
 497         u32 bke = TIM_BDTR_BKE(bi->index);
 498         u32 bkp = TIM_BDTR_BKP(bi->index);
 499         u32 bkf = TIM_BDTR_BKF(bi->index);
 500         u32 mask = bkf | bkp | bke;
 501         u32 bdtr;
 502
 503         bdtr = (bi->filter & TIM_BDTR_BKF_MASK) << shift | bke;
 504
 505         if (bi->level)
 506                 bdtr |= bkp;
 507
 508         regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);
 509
 510         regmap_read(priv->regmap, TIM_BDTR, &bdtr);
 511
 512         return (bdtr & bke) ? 0 : -EINVAL;
 513 }
 514
 515 static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv)
 516 {
 517         unsigned int i;
 518         int ret;
 519
 520         for (i = 0; i < priv->num_breakinputs; i++) {
 521                 ret = stm32_pwm_set_breakinput(priv, &priv->breakinputs[i]);
 522                 if (ret < 0)
 523                         return ret;
 524         }
 525
 526         return 0;
 527 }
 528
 529 static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv,
 530                                        struct device_node *np)
 531 {
 532         int nb, ret, array_size;
 533         unsigned int i;
 534
 535         nb = of_property_count_elems_of_size(np, "st,breakinput",
 536                                              sizeof(struct stm32_breakinput));
 537
 538         /*
 539          * Because "st,breakinput" parameter is optional do not make probe
 540          * failed if it doesn't exist.
 541          */
 542         if (nb <= 0)
 543                 return 0;
 544
 545         if (nb > MAX_BREAKINPUT)
 546                 return -EINVAL;
 547
 548         priv->num_breakinputs = nb;
 549         array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
 550         ret = of_property_read_u32_array(np, "st,breakinput",
 551                                          (u32 *)priv->breakinputs, array_size);
 552         if (ret)
 553                 return ret;
 554
 555         for (i = 0; i < priv->num_breakinputs; i++) {
 556                 if (priv->breakinputs[i].index > 1 ||
 557                     priv->breakinputs[i].level > 1 ||
 558                     priv->breakinputs[i].filter > 15)
 559                         return -EINVAL;
 560         }
 561
 562         return stm32_pwm_apply_breakinputs(priv);
 563 }
 564
 565 static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
 566 {
 567         u32 ccer;
 568
 569         /*
 570          * If complementary bit doesn't exist writing 1 will have no
 571          * effect so we can detect it.
 572          */
 573         regmap_update_bits(priv->regmap,
 574                            TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
 575         regmap_read(priv->regmap, TIM_CCER, &ccer);
 576         regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE, 0);
 577
 578         priv->have_complementary_output = (ccer != 0);
 579 }
 580
 581 static int stm32_pwm_detect_channels(struct stm32_pwm *priv)
 582 {
 583         u32 ccer;
 584         int npwm = 0;
 585
 586         /*
 587          * If channels enable bits don't exist writing 1 will have no
 588          * effect so we can detect and count them.
 589          */
 590         regmap_update_bits(priv->regmap,
 591                            TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
 592         regmap_read(priv->regmap, TIM_CCER, &ccer);
 593         regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);
 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         priv->chip.of_xlate = of_pwm_xlate_with_flags;
 627         priv->chip.of_pwm_n_cells = 3;
 628
 629         if (!priv->regmap || !priv->clk)
 630                 return -EINVAL;
 631
 632         ret = stm32_pwm_probe_breakinputs(priv, np);
 633         if (ret)
 634                 return ret;
 635
 636         stm32_pwm_detect_complementary(priv);
 637
 638         priv->chip.base = -1;
 639         priv->chip.dev = dev;
 640         priv->chip.ops = &stm32pwm_ops;
 641         priv->chip.npwm = stm32_pwm_detect_channels(priv);
 642
 643         ret = pwmchip_add(&priv->chip);
 644         if (ret < 0)
 645                 return ret;
 646
 647         platform_set_drvdata(pdev, priv);
 648
 649         return 0;
 650 }
 651
 652 static int stm32_pwm_remove(struct platform_device *pdev)
 653 {
 654         struct stm32_pwm *priv = platform_get_drvdata(pdev);
 655         unsigned int i;
 656
 657         for (i = 0; i < priv->chip.npwm; i++)
 658                 pwm_disable(&priv->chip.pwms[i]);
 659
 660         pwmchip_remove(&priv->chip);
 661
 662         return 0;
 663 }
 664
 665 static int __maybe_unused stm32_pwm_suspend(struct device *dev)
 666 {
 667         struct stm32_pwm *priv = dev_get_drvdata(dev);
 668         unsigned int i;
 669         u32 ccer, mask;
 670
 671         /* Look for active channels */
 672         ccer = active_channels(priv);
 673
 674         for (i = 0; i < priv->chip.npwm; i++) {
 675                 mask = TIM_CCER_CC1E << (i * 4);
 676                 if (ccer & mask) {
 677                         dev_err(dev, "PWM %u still in use by consumer %s\n",
 678                                 i, priv->chip.pwms[i].label);
 679                         return -EBUSY;
 680                 }
 681         }
 682
 683         return pinctrl_pm_select_sleep_state(dev);
 684 }
 685
 686 static int __maybe_unused stm32_pwm_resume(struct device *dev)
 687 {
 688         struct stm32_pwm *priv = dev_get_drvdata(dev);
 689         int ret;
 690
 691         ret = pinctrl_pm_select_default_state(dev);
 692         if (ret)
 693                 return ret;
 694
 695         /* restore breakinput registers that may have been lost in low power */
 696         return stm32_pwm_apply_breakinputs(priv);
 697 }
 698
 699 static SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume);
 700
 701 static const struct of_device_id stm32_pwm_of_match[] = {
 702         { .compatible = "st,stm32-pwm", },
 703         { /* end node */ },
 704 };
 705 MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
 706
 707 static struct platform_driver stm32_pwm_driver = {
 708         .probe  = stm32_pwm_probe,
 709         .remove = stm32_pwm_remove,
 710         .driver = {
 711                 .name = "stm32-pwm",
 712                 .of_match_table = stm32_pwm_of_match,
 713                 .pm = &stm32_pwm_pm_ops,
 714         },
 715 };
 716 module_platform_driver(stm32_pwm_driver);
 717
 718 MODULE_ALIAS("platform:stm32-pwm");
 719 MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
 720 MODULE_LICENSE("GPL v2");