drivers/pwm/pwm-sti.c

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