drivers/pwm/pwm-sti.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * PWM device driver for ST SoCs
   4  *
   5  * Copyright (C) 2013-2016 STMicroelectronics (R&D) Limited
   6  *
   7  * Author: Ajit Pal Singh <ajitpal.singh@st.com>
   8  *         Lee Jones <lee.jones@linaro.org>
   9  */
  10
  11 #include <linux/clk.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/math64.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/pwm.h>
  19 #include <linux/regmap.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/time.h>
  23 #include <linux/wait.h>
  24
  25 #define PWM_OUT_VAL(x)  (0x00 + (4 * (x))) /* Device's Duty Cycle register */
  26 #define PWM_CPT_VAL(x)  (0x10 + (4 * (x))) /* Capture value */
  27 #define PWM_CPT_EDGE(x) (0x30 + (4 * (x))) /* Edge to capture on */
  28
  29 #define STI_PWM_CTRL            0x50    /* Control/Config register */
  30 #define STI_INT_EN              0x54    /* Interrupt Enable/Disable register */
  31 #define STI_INT_STA             0x58    /* Interrupt Status register */
  32 #define PWM_INT_ACK             0x5c
  33 #define PWM_PRESCALE_LOW_MASK   0x0f
  34 #define PWM_PRESCALE_HIGH_MASK  0xf0
  35 #define PWM_CPT_EDGE_MASK       0x03
  36 #define PWM_INT_ACK_MASK        0x1ff
  37
  38 #define STI_MAX_CPT_DEVS        4
  39 #define CPT_DC_MAX              0xff
  40
  41 /* Regfield IDs */
  42 enum {
  43         /* Bits in PWM_CTRL*/
  44         PWMCLK_PRESCALE_LOW,
  45         PWMCLK_PRESCALE_HIGH,
  46         CPTCLK_PRESCALE,
  47
  48         PWM_OUT_EN,
  49         PWM_CPT_EN,
  50
  51         PWM_CPT_INT_EN,
  52         PWM_CPT_INT_STAT,
  53
  54         /* Keep last */
  55         MAX_REGFIELDS
  56 };
  57
  58 /*
  59  * Each capture input can be programmed to detect rising-edge, falling-edge,
  60  * either edge or neither egde.
  61  */
  62 enum sti_cpt_edge {
  63         CPT_EDGE_DISABLED,
  64         CPT_EDGE_RISING,
  65         CPT_EDGE_FALLING,
  66         CPT_EDGE_BOTH,
  67 };
  68
  69 struct sti_cpt_ddata {
  70         u32 snapshot[3];
  71         unsigned int index;
  72         struct mutex lock;
  73         wait_queue_head_t wait;
  74 };
  75
  76 struct sti_pwm_compat_data {
  77         const struct reg_field *reg_fields;
  78         unsigned int pwm_num_devs;
  79         unsigned int cpt_num_devs;
  80         unsigned int max_pwm_cnt;
  81         unsigned int max_prescale;
  82         struct sti_cpt_ddata *ddata;
  83 };
  84
  85 struct sti_pwm_chip {
  86         struct device *dev;
  87         struct clk *pwm_clk;
  88         struct clk *cpt_clk;
  89         struct regmap *regmap;
  90         struct sti_pwm_compat_data *cdata;
  91         struct regmap_field *prescale_low;
  92         struct regmap_field *prescale_high;
  93         struct regmap_field *pwm_out_en;
  94         struct regmap_field *pwm_cpt_en;
  95         struct regmap_field *pwm_cpt_int_en;
  96         struct regmap_field *pwm_cpt_int_stat;
  97         struct pwm_chip chip;
  98         struct pwm_device *cur;
  99         unsigned long configured;
 100         unsigned int en_count;
 101         struct mutex sti_pwm_lock; /* To sync between enable/disable calls */
 102         void __iomem *mmio;
 103 };
 104
 105 static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = {
 106         [PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3),
 107         [PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14),
 108         [CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8),
 109         [PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9),
 110         [PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10),
 111         [PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4),
 112         [PWM_CPT_INT_STAT] = REG_FIELD(STI_INT_STA, 1, 4),
 113 };
 114
 115 static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip)
 116 {
 117         return container_of(chip, struct sti_pwm_chip, chip);
 118 }
 119
 120 /*
 121  * Calculate the prescaler value corresponding to the period.
 122  */
 123 static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period,
 124                                 unsigned int *prescale)
 125 {
 126         struct sti_pwm_compat_data *cdata = pc->cdata;
 127         unsigned long clk_rate;
 128         unsigned long value;
 129         unsigned int ps;
 130
 131         clk_rate = clk_get_rate(pc->pwm_clk);
 132         if (!clk_rate) {
 133                 dev_err(pc->dev, "failed to get clock rate\n");
 134                 return -EINVAL;
 135         }
 136
 137         /*
 138          * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_cnt + 1)) - 1
 139          */
 140         value = NSEC_PER_SEC / clk_rate;
 141         value *= cdata->max_pwm_cnt + 1;
 142
 143         if (period % value)
 144                 return -EINVAL;
 145
 146         ps  = period / value - 1;
 147         if (ps > cdata->max_prescale)
 148                 return -EINVAL;
 149
 150         *prescale = ps;
 151
 152         return 0;
 153 }
 154
 155 /*
 156  * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. The
 157  * only way to change the period (apart from changing the PWM input clock) is
 158  * to change the PWM clock prescaler.
 159  *
 160  * The prescaler is of 8 bits, so 256 prescaler values and hence 256 possible
 161  * period values are supported (for a particular clock rate). The requested
 162  * period will be applied only if it matches one of these 256 values.
 163  */
 164 static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 165                           int duty_ns, int period_ns)
 166 {
 167         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 168         struct sti_pwm_compat_data *cdata = pc->cdata;
 169         unsigned int ncfg, value, prescale = 0;
 170         struct pwm_device *cur = pc->cur;
 171         struct device *dev = pc->dev;
 172         bool period_same = false;
 173         int ret;
 174
 175         ncfg = hweight_long(pc->configured);
 176         if (ncfg)
 177                 period_same = (period_ns == pwm_get_period(cur));
 178
 179         /*
 180          * Allow configuration changes if one of the following conditions
 181          * satisfy.
 182          * 1. No devices have been configured.
 183          * 2. Only one device has been configured and the new request is for
 184          *    the same device.
 185          * 3. Only one device has been configured and the new request is for
 186          *    a new device and period of the new device is same as the current
 187          *    configured period.
 188          * 4. More than one devices are configured and period of the new
 189          *    requestis the same as the current period.
 190          */
 191         if (!ncfg ||
 192             ((ncfg == 1) && (pwm->hwpwm == cur->hwpwm)) ||
 193             ((ncfg == 1) && (pwm->hwpwm != cur->hwpwm) && period_same) ||
 194             ((ncfg > 1) && period_same)) {
 195                 /* Enable clock before writing to PWM registers. */
 196                 ret = clk_enable(pc->pwm_clk);
 197                 if (ret)
 198                         return ret;
 199
 200                 ret = clk_enable(pc->cpt_clk);
 201                 if (ret)
 202                         return ret;
 203
 204                 if (!period_same) {
 205                         ret = sti_pwm_get_prescale(pc, period_ns, &prescale);
 206                         if (ret)
 207                                 goto clk_dis;
 208
 209                         value = prescale & PWM_PRESCALE_LOW_MASK;
 210
 211                         ret = regmap_field_write(pc->prescale_low, value);
 212                         if (ret)
 213                                 goto clk_dis;
 214
 215                         value = (prescale & PWM_PRESCALE_HIGH_MASK) >> 4;
 216
 217                         ret = regmap_field_write(pc->prescale_high, value);
 218                         if (ret)
 219                                 goto clk_dis;
 220                 }
 221
 222                 /*
 223                  * When PWMVal == 0, PWM pulse = 1 local clock cycle.
 224                  * When PWMVal == max_pwm_count,
 225                  * PWM pulse = (max_pwm_count + 1) local cycles,
 226                  * that is continuous pulse: signal never goes low.
 227                  */
 228                 value = cdata->max_pwm_cnt * duty_ns / period_ns;
 229
 230                 ret = regmap_write(pc->regmap, PWM_OUT_VAL(pwm->hwpwm), value);
 231                 if (ret)
 232                         goto clk_dis;
 233
 234                 ret = regmap_field_write(pc->pwm_cpt_int_en, 0);
 235
 236                 set_bit(pwm->hwpwm, &pc->configured);
 237                 pc->cur = pwm;
 238
 239                 dev_dbg(dev, "prescale:%u, period:%i, duty:%i, value:%u\n",
 240                         prescale, period_ns, duty_ns, value);
 241         } else {
 242                 return -EINVAL;
 243         }
 244
 245 clk_dis:
 246         clk_disable(pc->pwm_clk);
 247         clk_disable(pc->cpt_clk);
 248         return ret;
 249 }
 250
 251 static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 252 {
 253         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 254         struct device *dev = pc->dev;
 255         int ret = 0;
 256
 257         /*
 258          * Since we have a common enable for all PWM devices, do not enable if
 259          * already enabled.
 260          */
 261         mutex_lock(&pc->sti_pwm_lock);
 262
 263         if (!pc->en_count) {
 264                 ret = clk_enable(pc->pwm_clk);
 265                 if (ret)
 266                         goto out;
 267
 268                 ret = clk_enable(pc->cpt_clk);
 269                 if (ret)
 270                         goto out;
 271
 272                 ret = regmap_field_write(pc->pwm_out_en, 1);
 273                 if (ret) {
 274                         dev_err(dev, "failed to enable PWM device %u: %d\n",
 275                                 pwm->hwpwm, ret);
 276                         goto out;
 277                 }
 278         }
 279
 280         pc->en_count++;
 281
 282 out:
 283         mutex_unlock(&pc->sti_pwm_lock);
 284         return ret;
 285 }
 286
 287 static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 288 {
 289         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 290
 291         mutex_lock(&pc->sti_pwm_lock);
 292
 293         if (--pc->en_count) {
 294                 mutex_unlock(&pc->sti_pwm_lock);
 295                 return;
 296         }
 297
 298         regmap_field_write(pc->pwm_out_en, 0);
 299
 300         clk_disable(pc->pwm_clk);
 301         clk_disable(pc->cpt_clk);
 302
 303         mutex_unlock(&pc->sti_pwm_lock);
 304 }
 305
 306 static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 307 {
 308         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 309
 310         clear_bit(pwm->hwpwm, &pc->configured);
 311 }
 312
 313 static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
 314                            struct pwm_capture *result, unsigned long timeout)
 315 {
 316         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 317         struct sti_pwm_compat_data *cdata = pc->cdata;
 318         struct sti_cpt_ddata *ddata = &cdata->ddata[pwm->hwpwm];
 319         struct device *dev = pc->dev;
 320         unsigned int effective_ticks;
 321         unsigned long long high, low;
 322         int ret;
 323
 324         if (pwm->hwpwm >= cdata->cpt_num_devs) {
 325                 dev_err(dev, "device %u is not valid\n", pwm->hwpwm);
 326                 return -EINVAL;
 327         }
 328
 329         mutex_lock(&ddata->lock);
 330         ddata->index = 0;
 331
 332         /* Prepare capture measurement */
 333         regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_RISING);
 334         regmap_field_write(pc->pwm_cpt_int_en, BIT(pwm->hwpwm));
 335
 336         /* Enable capture */
 337         ret = regmap_field_write(pc->pwm_cpt_en, 1);
 338         if (ret) {
 339                 dev_err(dev, "failed to enable PWM capture %u: %d\n",
 340                         pwm->hwpwm, ret);
 341                 goto out;
 342         }
 343
 344         ret = wait_event_interruptible_timeout(ddata->wait, ddata->index > 1,
 345                                                msecs_to_jiffies(timeout));
 346
 347         regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_DISABLED);
 348
 349         if (ret == -ERESTARTSYS)
 350                 goto out;
 351
 352         switch (ddata->index) {
 353         case 0:
 354         case 1:
 355                 /*
 356                  * Getting here could mean:
 357                  *  - input signal is constant of less than 1 Hz
 358                  *  - there is no input signal at all
 359                  *
 360                  * In such case the frequency is rounded down to 0
 361                  */
 362                 result->period = 0;
 363                 result->duty_cycle = 0;
 364
 365                 break;
 366
 367         case 2:
 368                 /* We have everying we need */
 369                 high = ddata->snapshot[1] - ddata->snapshot[0];
 370                 low = ddata->snapshot[2] - ddata->snapshot[1];
 371
 372                 effective_ticks = clk_get_rate(pc->cpt_clk);
 373
 374                 result->period = (high + low) * NSEC_PER_SEC;
 375                 result->period /= effective_ticks;
 376
 377                 result->duty_cycle = high * NSEC_PER_SEC;
 378                 result->duty_cycle /= effective_ticks;
 379
 380                 break;
 381
 382         default:
 383                 dev_err(dev, "internal error\n");
 384                 break;
 385         }
 386
 387 out:
 388         /* Disable capture */
 389         regmap_field_write(pc->pwm_cpt_en, 0);
 390
 391         mutex_unlock(&ddata->lock);
 392         return ret;
 393 }
 394
 395 static int sti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 396                          const struct pwm_state *state)
 397 {
 398         int err;
 399
 400         if (state->polarity != PWM_POLARITY_NORMAL)
 401                 return -EINVAL;
 402
 403         if (!state->enabled) {
 404                 if (pwm->state.enabled)
 405                         sti_pwm_disable(chip, pwm);
 406
 407                 return 0;
 408         }
 409
 410         err = sti_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
 411         if (err)
 412                 return err;
 413
 414         if (!pwm->state.enabled)
 415                 err = sti_pwm_enable(chip, pwm);
 416
 417         return err;
 418 }
 419
 420 static const struct pwm_ops sti_pwm_ops = {
 421         .capture = sti_pwm_capture,
 422         .apply = sti_pwm_apply,
 423         .free = sti_pwm_free,
 424         .owner = THIS_MODULE,
 425 };
 426
 427 static irqreturn_t sti_pwm_interrupt(int irq, void *data)
 428 {
 429         struct sti_pwm_chip *pc = data;
 430         struct device *dev = pc->dev;
 431         struct sti_cpt_ddata *ddata;
 432         int devicenum;
 433         unsigned int cpt_int_stat;
 434         unsigned int reg;
 435         int ret = IRQ_NONE;
 436
 437         ret = regmap_field_read(pc->pwm_cpt_int_stat, &cpt_int_stat);
 438         if (ret)
 439                 return ret;
 440
 441         while (cpt_int_stat) {
 442                 devicenum = ffs(cpt_int_stat) - 1;
 443
 444                 ddata = &pc->cdata->ddata[devicenum];
 445
 446                 /*
 447                  * Capture input:
 448                  *    _______                   _______
 449                  *   |       |                 |       |
 450                  * __|       |_________________|       |________
 451                  *   ^0      ^1                ^2
 452                  *
 453                  * Capture start by the first available rising edge. When a
 454                  * capture event occurs, capture value (CPT_VALx) is stored,
 455                  * index incremented, capture edge changed.
 456                  *
 457                  * After the capture, if the index > 1, we have collected the
 458                  * necessary data so we signal the thread waiting for it and
 459                  * disable the capture by setting capture edge to none
 460                  */
 461
 462                 regmap_read(pc->regmap,
 463                             PWM_CPT_VAL(devicenum),
 464                             &ddata->snapshot[ddata->index]);
 465
 466                 switch (ddata->index) {
 467                 case 0:
 468                 case 1:
 469                         regmap_read(pc->regmap, PWM_CPT_EDGE(devicenum), &reg);
 470                         reg ^= PWM_CPT_EDGE_MASK;
 471                         regmap_write(pc->regmap, PWM_CPT_EDGE(devicenum), reg);
 472
 473                         ddata->index++;
 474                         break;
 475
 476                 case 2:
 477                         regmap_write(pc->regmap,
 478                                      PWM_CPT_EDGE(devicenum),
 479                                      CPT_EDGE_DISABLED);
 480                         wake_up(&ddata->wait);
 481                         break;
 482
 483                 default:
 484                         dev_err(dev, "Internal error\n");
 485                 }
 486
 487                 cpt_int_stat &= ~BIT_MASK(devicenum);
 488
 489                 ret = IRQ_HANDLED;
 490         }
 491
 492         /* Just ACK everything */
 493         regmap_write(pc->regmap, PWM_INT_ACK, PWM_INT_ACK_MASK);
 494
 495         return ret;
 496 }
 497
 498 static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
 499 {
 500         struct device *dev = pc->dev;
 501         const struct reg_field *reg_fields;
 502         struct device_node *np = dev->of_node;
 503         struct sti_pwm_compat_data *cdata = pc->cdata;
 504         u32 num_devs;
 505         int ret;
 506
 507         ret = of_property_read_u32(np, "st,pwm-num-chan", &num_devs);
 508         if (!ret)
 509                 cdata->pwm_num_devs = num_devs;
 510
 511         ret = of_property_read_u32(np, "st,capture-num-chan", &num_devs);
 512         if (!ret)
 513                 cdata->cpt_num_devs = num_devs;
 514
 515         if (!cdata->pwm_num_devs && !cdata->cpt_num_devs) {
 516                 dev_err(dev, "No channels configured\n");
 517                 return -EINVAL;
 518         }
 519
 520         reg_fields = cdata->reg_fields;
 521
 522         pc->prescale_low = devm_regmap_field_alloc(dev, pc->regmap,
 523                                         reg_fields[PWMCLK_PRESCALE_LOW]);
 524         if (IS_ERR(pc->prescale_low))
 525                 return PTR_ERR(pc->prescale_low);
 526
 527         pc->prescale_high = devm_regmap_field_alloc(dev, pc->regmap,
 528                                         reg_fields[PWMCLK_PRESCALE_HIGH]);
 529         if (IS_ERR(pc->prescale_high))
 530                 return PTR_ERR(pc->prescale_high);
 531
 532         pc->pwm_out_en = devm_regmap_field_alloc(dev, pc->regmap,
 533                                                  reg_fields[PWM_OUT_EN]);
 534         if (IS_ERR(pc->pwm_out_en))
 535                 return PTR_ERR(pc->pwm_out_en);
 536
 537         pc->pwm_cpt_en = devm_regmap_field_alloc(dev, pc->regmap,
 538                                                  reg_fields[PWM_CPT_EN]);
 539         if (IS_ERR(pc->pwm_cpt_en))
 540                 return PTR_ERR(pc->pwm_cpt_en);
 541
 542         pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap,
 543                                                 reg_fields[PWM_CPT_INT_EN]);
 544         if (IS_ERR(pc->pwm_cpt_int_en))
 545                 return PTR_ERR(pc->pwm_cpt_int_en);
 546
 547         pc->pwm_cpt_int_stat = devm_regmap_field_alloc(dev, pc->regmap,
 548                                                 reg_fields[PWM_CPT_INT_STAT]);
 549         if (PTR_ERR_OR_ZERO(pc->pwm_cpt_int_stat))
 550                 return PTR_ERR(pc->pwm_cpt_int_stat);
 551
 552         return 0;
 553 }
 554
 555 static const struct regmap_config sti_pwm_regmap_config = {
 556         .reg_bits = 32,
 557         .val_bits = 32,
 558         .reg_stride = 4,
 559 };
 560
 561 static int sti_pwm_probe(struct platform_device *pdev)
 562 {
 563         struct device *dev = &pdev->dev;
 564         struct sti_pwm_compat_data *cdata;
 565         struct sti_pwm_chip *pc;
 566         unsigned int i;
 567         int irq, ret;
 568
 569         pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
 570         if (!pc)
 571                 return -ENOMEM;
 572
 573         cdata = devm_kzalloc(dev, sizeof(*cdata), GFP_KERNEL);
 574         if (!cdata)
 575                 return -ENOMEM;
 576
 577         pc->mmio = devm_platform_ioremap_resource(pdev, 0);
 578         if (IS_ERR(pc->mmio))
 579                 return PTR_ERR(pc->mmio);
 580
 581         pc->regmap = devm_regmap_init_mmio(dev, pc->mmio,
 582                                            &sti_pwm_regmap_config);
 583         if (IS_ERR(pc->regmap))
 584                 return PTR_ERR(pc->regmap);
 585
 586         irq = platform_get_irq(pdev, 0);
 587         if (irq < 0)
 588                 return irq;
 589
 590         ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt, 0,
 591                                pdev->name, pc);
 592         if (ret < 0) {
 593                 dev_err(&pdev->dev, "Failed to request IRQ\n");
 594                 return ret;
 595         }
 596
 597         /*
 598          * Setup PWM data with default values: some values could be replaced
 599          * with specific ones provided from Device Tree.
 600          */
 601         cdata->reg_fields = sti_pwm_regfields;
 602         cdata->max_prescale = 0xff;
 603         cdata->max_pwm_cnt = 255;
 604         cdata->pwm_num_devs = 0;
 605         cdata->cpt_num_devs = 0;
 606
 607         pc->cdata = cdata;
 608         pc->dev = dev;
 609         pc->en_count = 0;
 610         mutex_init(&pc->sti_pwm_lock);
 611
 612         ret = sti_pwm_probe_dt(pc);
 613         if (ret)
 614                 return ret;
 615
 616         if (cdata->pwm_num_devs) {
 617                 pc->pwm_clk = of_clk_get_by_name(dev->of_node, "pwm");
 618                 if (IS_ERR(pc->pwm_clk)) {
 619                         dev_err(dev, "failed to get PWM clock\n");
 620                         return PTR_ERR(pc->pwm_clk);
 621                 }
 622
 623                 ret = clk_prepare(pc->pwm_clk);
 624                 if (ret) {
 625                         dev_err(dev, "failed to prepare clock\n");
 626                         return ret;
 627                 }
 628         }
 629
 630         if (cdata->cpt_num_devs) {
 631                 pc->cpt_clk = of_clk_get_by_name(dev->of_node, "capture");
 632                 if (IS_ERR(pc->cpt_clk)) {
 633                         dev_err(dev, "failed to get PWM capture clock\n");
 634                         return PTR_ERR(pc->cpt_clk);
 635                 }
 636
 637                 ret = clk_prepare(pc->cpt_clk);
 638                 if (ret) {
 639                         dev_err(dev, "failed to prepare clock\n");
 640                         return ret;
 641                 }
 642
 643                 cdata->ddata = devm_kzalloc(dev, cdata->cpt_num_devs * sizeof(*cdata->ddata), GFP_KERNEL);
 644                 if (!cdata->ddata)
 645                         return -ENOMEM;
 646         }
 647
 648         pc->chip.dev = dev;
 649         pc->chip.ops = &sti_pwm_ops;
 650         pc->chip.npwm = pc->cdata->pwm_num_devs;
 651
 652         for (i = 0; i < cdata->cpt_num_devs; i++) {
 653                 struct sti_cpt_ddata *ddata = &cdata->ddata[i];
 654
 655                 init_waitqueue_head(&ddata->wait);
 656                 mutex_init(&ddata->lock);
 657         }
 658
 659         ret = pwmchip_add(&pc->chip);
 660         if (ret < 0) {
 661                 clk_unprepare(pc->pwm_clk);
 662                 clk_unprepare(pc->cpt_clk);
 663                 return ret;
 664         }
 665
 666         platform_set_drvdata(pdev, pc);
 667
 668         return 0;
 669 }
 670
 671 static void sti_pwm_remove(struct platform_device *pdev)
 672 {
 673         struct sti_pwm_chip *pc = platform_get_drvdata(pdev);
 674
 675         pwmchip_remove(&pc->chip);
 676
 677         clk_unprepare(pc->pwm_clk);
 678         clk_unprepare(pc->cpt_clk);
 679 }
 680
 681 static const struct of_device_id sti_pwm_of_match[] = {
 682         { .compatible = "st,sti-pwm", },
 683         { /* sentinel */ }
 684 };
 685 MODULE_DEVICE_TABLE(of, sti_pwm_of_match);
 686
 687 static struct platform_driver sti_pwm_driver = {
 688         .driver = {
 689                 .name = "sti-pwm",
 690                 .of_match_table = sti_pwm_of_match,
 691         },
 692         .probe = sti_pwm_probe,
 693         .remove_new = sti_pwm_remove,
 694 };
 695 module_platform_driver(sti_pwm_driver);
 696
 697 MODULE_AUTHOR("Ajit Pal Singh <ajitpal.singh@st.com>");
 698 MODULE_DESCRIPTION("STMicroelectronics ST PWM driver");
 699 MODULE_LICENSE("GPL");