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_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         .apply = stm32_pwm_apply_locked,
 491         .capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL,
 492 };
 493
 494 static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
 495                                     const struct stm32_breakinput *bi)
 496 {
 497         u32 shift = TIM_BDTR_BKF_SHIFT(bi->index);
 498         u32 bke = TIM_BDTR_BKE(bi->index);
 499         u32 bkp = TIM_BDTR_BKP(bi->index);
 500         u32 bkf = TIM_BDTR_BKF(bi->index);
 501         u32 mask = bkf | bkp | bke;
 502         u32 bdtr;
 503
 504         bdtr = (bi->filter & TIM_BDTR_BKF_MASK) << shift | bke;
 505
 506         if (bi->level)
 507                 bdtr |= bkp;
 508
 509         regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);
 510
 511         regmap_read(priv->regmap, TIM_BDTR, &bdtr);
 512
 513         return (bdtr & bke) ? 0 : -EINVAL;
 514 }
 515
 516 static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv)
 517 {
 518         unsigned int i;
 519         int ret;
 520
 521         for (i = 0; i < priv->num_breakinputs; i++) {
 522                 ret = stm32_pwm_set_breakinput(priv, &priv->breakinputs[i]);
 523                 if (ret < 0)
 524                         return ret;
 525         }
 526
 527         return 0;
 528 }
 529
 530 static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv,
 531                                        struct device_node *np)
 532 {
 533         int nb, ret, array_size;
 534         unsigned int i;
 535
 536         nb = of_property_count_elems_of_size(np, "st,breakinput",
 537                                              sizeof(struct stm32_breakinput));
 538
 539         /*
 540          * Because "st,breakinput" parameter is optional do not make probe
 541          * failed if it doesn't exist.
 542          */
 543         if (nb <= 0)
 544                 return 0;
 545
 546         if (nb > MAX_BREAKINPUT)
 547                 return -EINVAL;
 548
 549         priv->num_breakinputs = nb;
 550         array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
 551         ret = of_property_read_u32_array(np, "st,breakinput",
 552                                          (u32 *)priv->breakinputs, array_size);
 553         if (ret)
 554                 return ret;
 555
 556         for (i = 0; i < priv->num_breakinputs; i++) {
 557                 if (priv->breakinputs[i].index > 1 ||
 558                     priv->breakinputs[i].level > 1 ||
 559                     priv->breakinputs[i].filter > 15)
 560                         return -EINVAL;
 561         }
 562
 563         return stm32_pwm_apply_breakinputs(priv);
 564 }
 565
 566 static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
 567 {
 568         u32 ccer;
 569
 570         /*
 571          * If complementary bit doesn't exist writing 1 will have no
 572          * effect so we can detect it.
 573          */
 574         regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE);
 575         regmap_read(priv->regmap, TIM_CCER, &ccer);
 576         regmap_clear_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE);
 577
 578         priv->have_complementary_output = (ccer != 0);
 579 }
 580
 581 static unsigned int stm32_pwm_detect_channels(struct stm32_pwm *priv,
 582                                               unsigned int *num_enabled)
 583 {
 584         u32 ccer, ccer_backup;
 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_read(priv->regmap, TIM_CCER, &ccer_backup);
 591         regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
 592         regmap_read(priv->regmap, TIM_CCER, &ccer);
 593         regmap_write(priv->regmap, TIM_CCER, ccer_backup);
 594
 595         *num_enabled = hweight32(ccer_backup & TIM_CCER_CCXE);
 596
 597         return hweight32(ccer & TIM_CCER_CCXE);
 598 }
 599
 600 static int stm32_pwm_probe(struct platform_device *pdev)
 601 {
 602         struct device *dev = &pdev->dev;
 603         struct device_node *np = dev->of_node;
 604         struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
 605         struct stm32_pwm *priv;
 606         unsigned int num_enabled;
 607         unsigned int i;
 608         int ret;
 609
 610         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 611         if (!priv)
 612                 return -ENOMEM;
 613
 614         mutex_init(&priv->lock);
 615         priv->regmap = ddata->regmap;
 616         priv->clk = ddata->clk;
 617         priv->max_arr = ddata->max_arr;
 618
 619         if (!priv->regmap || !priv->clk)
 620                 return -EINVAL;
 621
 622         ret = stm32_pwm_probe_breakinputs(priv, np);
 623         if (ret)
 624                 return ret;
 625
 626         stm32_pwm_detect_complementary(priv);
 627
 628         priv->chip.dev = dev;
 629         priv->chip.ops = &stm32pwm_ops;
 630         priv->chip.npwm = stm32_pwm_detect_channels(priv, &num_enabled);
 631
 632         /* Initialize clock refcount to number of enabled PWM channels. */
 633         for (i = 0; i < num_enabled; i++)
 634                 clk_enable(priv->clk);
 635
 636         ret = devm_pwmchip_add(dev, &priv->chip);
 637         if (ret < 0)
 638                 return ret;
 639
 640         platform_set_drvdata(pdev, priv);
 641
 642         return 0;
 643 }
 644
 645 static int __maybe_unused stm32_pwm_suspend(struct device *dev)
 646 {
 647         struct stm32_pwm *priv = dev_get_drvdata(dev);
 648         unsigned int i;
 649         u32 ccer, mask;
 650
 651         /* Look for active channels */
 652         ccer = active_channels(priv);
 653
 654         for (i = 0; i < priv->chip.npwm; i++) {
 655                 mask = TIM_CCER_CC1E << (i * 4);
 656                 if (ccer & mask) {
 657                         dev_err(dev, "PWM %u still in use by consumer %s\n",
 658                                 i, priv->chip.pwms[i].label);
 659                         return -EBUSY;
 660                 }
 661         }
 662
 663         return pinctrl_pm_select_sleep_state(dev);
 664 }
 665
 666 static int __maybe_unused stm32_pwm_resume(struct device *dev)
 667 {
 668         struct stm32_pwm *priv = dev_get_drvdata(dev);
 669         int ret;
 670
 671         ret = pinctrl_pm_select_default_state(dev);
 672         if (ret)
 673                 return ret;
 674
 675         /* restore breakinput registers that may have been lost in low power */
 676         return stm32_pwm_apply_breakinputs(priv);
 677 }
 678
 679 static SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume);
 680
 681 static const struct of_device_id stm32_pwm_of_match[] = {
 682         { .compatible = "st,stm32-pwm", },
 683         { /* end node */ },
 684 };
 685 MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
 686
 687 static struct platform_driver stm32_pwm_driver = {
 688         .probe  = stm32_pwm_probe,
 689         .driver = {
 690                 .name = "stm32-pwm",
 691                 .of_match_table = stm32_pwm_of_match,
 692                 .pm = &stm32_pwm_pm_ops,
 693         },
 694 };
 695 module_platform_driver(stm32_pwm_driver);
 696
 697 MODULE_ALIAS("platform:stm32-pwm");
 698 MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
 699 MODULE_LICENSE("GPL v2");