drivers/pwm/pwm-sti.c

   1 /*
   2  * PWM device driver for ST SoCs.
   3  * Author: Ajit Pal Singh <ajitpal.singh@st.com>
   4  *
   5  * Copyright (C) 2013-2014 STMicroelectronics (R&D) Limited
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include <linux/clk.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/math64.h>
  16 #include <linux/mfd/syscon.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/pwm.h>
  21 #include <linux/regmap.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/time.h>
  25 #include <linux/wait.h>
  26
  27 #define PWM_OUT_VAL(x)  (0x00 + (4 * (x))) /* Device's Duty Cycle register */
  28 #define PWM_CPT_VAL(x)  (0x10 + (4 * (x))) /* Capture value */
  29 #define PWM_CPT_EDGE(x) (0x30 + (4 * (x))) /* Edge to capture on */
  30
  31 #define STI_PWM_CTRL            0x50    /* Control/Config register */
  32 #define STI_INT_EN              0x54    /* Interrupt Enable/Disable register */
  33 #define STI_INT_STA             0x58    /* Interrupt Status register */
  34 #define PWM_INT_ACK                     0x5c
  35 #define PWM_PRESCALE_LOW_MASK           0x0f
  36 #define PWM_PRESCALE_HIGH_MASK          0xf0
  37 #define PWM_CPT_EDGE_MASK               0x03
  38 #define PWM_INT_ACK_MASK                0x1ff
  39
  40 #define STI_MAX_CPT_DEVS                4
  41 #define CPT_DC_MAX                      0xff
  42
  43 /* Regfield IDs */
  44 enum {
  45         /* Bits in PWM_CTRL*/
  46         PWMCLK_PRESCALE_LOW,
  47         PWMCLK_PRESCALE_HIGH,
  48         CPTCLK_PRESCALE,
  49
  50         PWM_OUT_EN,
  51         PWM_CPT_EN,
  52
  53         PWM_CPT_INT_EN,
  54         PWM_CPT_INT_STAT,
  55
  56         /* Keep last */
  57         MAX_REGFIELDS
  58 };
  59
  60 /* Each capture input can be programmed to detect rising-edge, falling-edge,
  61  * either edge or neither egde
  62  */
  63 enum sti_cpt_edge {
  64         CPT_EDGE_DISABLED,
  65         CPT_EDGE_RISING,
  66         CPT_EDGE_FALLING,
  67         CPT_EDGE_BOTH,
  68 };
  69
  70 struct sti_cpt_ddata {
  71         u32 snapshot[3];
  72         unsigned int index;
  73         struct mutex lock;
  74         wait_queue_head_t wait;
  75 };
  76
  77 struct sti_pwm_compat_data {
  78         const struct reg_field *reg_fields;
  79         unsigned int pwm_num_devs;
  80         unsigned int cpt_num_devs;
  81         unsigned int max_pwm_cnt;
  82         unsigned int max_prescale;
  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 val;
 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_count + 1)) - 1
 139          */
 140         val = NSEC_PER_SEC / clk_rate;
 141         val *= cdata->max_pwm_cnt + 1;
 142
 143         if (period % val) {
 144                 return -EINVAL;
 145         } else {
 146                 ps  = period / val - 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.
 157  * The only way to change the period (apart from changing the PWM input clock)
 158  * is to change the PWM clock prescaler.
 159  * The prescaler is of 8 bits, so 256 prescaler values and hence
 160  * 256 possible period values are supported (for a particular clock rate).
 161  * The requested period will be applied only if it matches one of these
 162  * 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         struct pwm_device *cur = pc->cur;
 170         struct device *dev = pc->dev;
 171         unsigned int prescale = 0, pwmvalx;
 172         int ret;
 173         unsigned int ncfg;
 174         bool period_same = false;
 175
 176         ncfg = hweight_long(pc->configured);
 177         if (ncfg)
 178                 period_same = (period_ns == pwm_get_period(cur));
 179
 180         /* Allow configuration changes if one of the
 181          * following conditions satisfy.
 182          * 1. No devices have been configured.
 183          * 2. Only one device has been configured and the new request
 184          *    is for the same device.
 185          * 3. Only one device has been configured and the new request is
 186          *    for a new device and period of the new device is same as
 187          *    the current 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                         ret =
 210                         regmap_field_write(pc->prescale_low,
 211                                            prescale & PWM_PRESCALE_LOW_MASK);
 212                         if (ret)
 213                                 goto clk_dis;
 214
 215                         ret =
 216                         regmap_field_write(pc->prescale_high,
 217                                 (prescale & PWM_PRESCALE_HIGH_MASK) >> 4);
 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                 pwmvalx = cdata->max_pwm_cnt * duty_ns / period_ns;
 229
 230                 ret = regmap_write(pc->regmap,
 231                                    PWM_OUT_VAL(pwm->hwpwm), pwmvalx);
 232                 if (ret)
 233                         goto clk_dis;
 234
 235                 ret = regmap_field_write(pc->pwm_cpt_int_en, 0);
 236
 237                 set_bit(pwm->hwpwm, &pc->configured);
 238                 pc->cur = pwm;
 239
 240                 dev_dbg(dev, "prescale:%u, period:%i, duty:%i, pwmvalx:%u\n",
 241                         prescale, period_ns, duty_ns, pwmvalx);
 242         } else {
 243                 return -EINVAL;
 244         }
 245
 246 clk_dis:
 247         clk_disable(pc->pwm_clk);
 248         clk_disable(pc->cpt_clk);
 249         return ret;
 250 }
 251
 252 static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 253 {
 254         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 255         struct device *dev = pc->dev;
 256         int ret = 0;
 257
 258         /*
 259          * Since we have a common enable for all PWM devices,
 260          * do not enable if already enabled.
 261          */
 262         mutex_lock(&pc->sti_pwm_lock);
 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:%d\n",
 275                                 pwm->hwpwm);
 276                         goto out;
 277                 }
 278         }
 279         pc->en_count++;
 280 out:
 281         mutex_unlock(&pc->sti_pwm_lock);
 282         return ret;
 283 }
 284
 285 static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 286 {
 287         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 288
 289         mutex_lock(&pc->sti_pwm_lock);
 290         if (--pc->en_count) {
 291                 mutex_unlock(&pc->sti_pwm_lock);
 292                 return;
 293         }
 294         regmap_field_write(pc->pwm_out_en, 0);
 295
 296         clk_disable(pc->pwm_clk);
 297         clk_disable(pc->cpt_clk);
 298         mutex_unlock(&pc->sti_pwm_lock);
 299 }
 300
 301 static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 302 {
 303         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 304
 305         clear_bit(pwm->hwpwm, &pc->configured);
 306 }
 307
 308 static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
 309                            struct pwm_capture *result, unsigned long timeout)
 310 {
 311         struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 312         struct sti_pwm_compat_data *cdata = pc->cdata;
 313         struct sti_cpt_ddata *ddata = pwm_get_chip_data(pwm);
 314         struct device *dev = pc->dev;
 315         unsigned int effective_ticks;
 316         unsigned long long high, low;
 317         int ret;
 318
 319         if (pwm->hwpwm >= cdata->cpt_num_devs) {
 320                 dev_err(dev, "device %u is not valid\n", pwm->hwpwm);
 321                 return -EINVAL;
 322         }
 323
 324         mutex_lock(&ddata->lock);
 325         ddata->index = 0;
 326
 327         /* Prepare capture measurement */
 328         regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_RISING);
 329         regmap_field_write(pc->pwm_cpt_int_en, BIT(pwm->hwpwm));
 330
 331         /* Enable capture */
 332         ret = regmap_field_write(pc->pwm_cpt_en, 1);
 333         if (ret) {
 334                 dev_err(dev, "failed to enable PWM capture %u: %d\n",
 335                         pwm->hwpwm, ret);
 336                 goto out;
 337         }
 338
 339         ret = wait_event_interruptible_timeout(ddata->wait, ddata->index > 1,
 340                                                msecs_to_jiffies(timeout));
 341
 342         regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_DISABLED);
 343
 344         if (ret == -ERESTARTSYS)
 345                 goto out;
 346
 347         switch (ddata->index) {
 348         case 0:
 349         case 1:
 350                 /*
 351                  * Getting here could mean:
 352                  *  - input signal is constant of less than 1 Hz
 353                  *  - there is no input signal at all
 354                  *
 355                  * In such case the frequency is rounded down to 0
 356                  */
 357                 result->period = 0;
 358                 result->duty_cycle = 0;
 359
 360                 break;
 361
 362         case 2:
 363                 /* We have everying we need */
 364                 high = ddata->snapshot[1] - ddata->snapshot[0];
 365                 low = ddata->snapshot[2] - ddata->snapshot[1];
 366
 367                 effective_ticks = clk_get_rate(pc->cpt_clk);
 368
 369                 result->period = (high + low) * NSEC_PER_SEC;
 370                 result->period /= effective_ticks;
 371
 372                 result->duty_cycle = high * NSEC_PER_SEC;
 373                 result->duty_cycle /= effective_ticks;
 374
 375                 break;
 376
 377         default:
 378                 dev_err(dev, "internal error\n");
 379                 break;
 380         }
 381
 382 out:
 383         /* Disable capture */
 384         regmap_field_write(pc->pwm_cpt_en, 0);
 385
 386         mutex_unlock(&ddata->lock);
 387         return ret;
 388 }
 389
 390 static const struct pwm_ops sti_pwm_ops = {
 391         .capture = sti_pwm_capture,
 392         .config = sti_pwm_config,
 393         .enable = sti_pwm_enable,
 394         .disable = sti_pwm_disable,
 395         .free = sti_pwm_free,
 396         .owner = THIS_MODULE,
 397 };
 398
 399 static irqreturn_t sti_pwm_interrupt(int irq, void *data)
 400 {
 401         struct sti_pwm_chip *pc = data;
 402         struct device *dev = pc->dev;
 403         struct sti_cpt_ddata *ddata;
 404         int devicenum;
 405         unsigned int cpt_int_stat;
 406         unsigned int reg;
 407         int ret = IRQ_NONE;
 408
 409         ret = regmap_field_read(pc->pwm_cpt_int_stat, &cpt_int_stat);
 410         if (ret)
 411                 return ret;
 412
 413         while (cpt_int_stat) {
 414                 devicenum = ffs(cpt_int_stat) - 1;
 415
 416                 ddata = pwm_get_chip_data(&pc->chip.pwms[devicenum]);
 417
 418                 /*
 419                  * Capture input:
 420                  *    _______                   _______
 421                  *   |       |                 |       |
 422                  * __|       |_________________|       |________
 423                  *   ^0      ^1                ^2
 424                  *
 425                  * Capture start by the first available rising edge
 426                  * When a capture event occurs, capture value (CPT_VALx)
 427                  * is stored, index incremented, capture edge changed.
 428                  *
 429                  * After the capture, if the index > 1, we have collected
 430                  * the necessary data so we signal the thread waiting for it
 431                  * and disable the capture by setting capture edge to none
 432                  *
 433                  */
 434
 435                 regmap_read(pc->regmap,
 436                             PWM_CPT_VAL(devicenum),
 437                             &ddata->snapshot[ddata->index]);
 438
 439                 switch (ddata->index) {
 440                 case 0:
 441                 case 1:
 442                         regmap_read(pc->regmap, PWM_CPT_EDGE(devicenum), &reg);
 443                         reg ^= PWM_CPT_EDGE_MASK;
 444                         regmap_write(pc->regmap, PWM_CPT_EDGE(devicenum), reg);
 445
 446                         ddata->index++;
 447                         break;
 448                 case 2:
 449                         regmap_write(pc->regmap,
 450                                      PWM_CPT_EDGE(devicenum),
 451                                      CPT_EDGE_DISABLED);
 452                         wake_up(&ddata->wait);
 453                         break;
 454                 default:
 455                         dev_err(dev, "Internal error\n");
 456                 }
 457
 458                 cpt_int_stat &= ~BIT_MASK(devicenum);
 459
 460                 ret = IRQ_HANDLED;
 461         }
 462
 463         /* Just ACK everything */
 464         regmap_write(pc->regmap, PWM_INT_ACK, PWM_INT_ACK_MASK);
 465
 466         return ret;
 467 }
 468
 469 static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
 470 {
 471         struct device *dev = pc->dev;
 472         const struct reg_field *reg_fields;
 473         struct device_node *np = dev->of_node;
 474         struct sti_pwm_compat_data *cdata = pc->cdata;
 475         u32 num_devs;
 476         int ret;
 477
 478         ret = of_property_read_u32(np, "st,pwm-num-chan", &num_devs);
 479         if (!ret)
 480                 cdata->pwm_num_devs = num_devs;
 481
 482         ret = of_property_read_u32(np, "st,capture-num-chan", &num_devs);
 483         if (!ret)
 484                 cdata->cpt_num_devs = num_devs;
 485
 486         if (!cdata->pwm_num_devs && !cdata->cpt_num_devs) {
 487                 dev_err(dev, "No channels configured\n");
 488                 return -EINVAL;
 489         }
 490
 491         reg_fields = cdata->reg_fields;
 492
 493         pc->prescale_low = devm_regmap_field_alloc(dev, pc->regmap,
 494                                         reg_fields[PWMCLK_PRESCALE_LOW]);
 495         if (IS_ERR(pc->prescale_low))
 496                 return PTR_ERR(pc->prescale_low);
 497
 498         pc->prescale_high = devm_regmap_field_alloc(dev, pc->regmap,
 499                                         reg_fields[PWMCLK_PRESCALE_HIGH]);
 500         if (IS_ERR(pc->prescale_high))
 501                 return PTR_ERR(pc->prescale_high);
 502
 503
 504         pc->pwm_out_en = devm_regmap_field_alloc(dev, pc->regmap,
 505                                                  reg_fields[PWM_OUT_EN]);
 506         if (IS_ERR(pc->pwm_out_en))
 507                 return PTR_ERR(pc->pwm_out_en);
 508
 509         pc->pwm_cpt_en = devm_regmap_field_alloc(dev, pc->regmap,
 510                                                  reg_fields[PWM_CPT_EN]);
 511         if (IS_ERR(pc->pwm_cpt_en))
 512                 return PTR_ERR(pc->pwm_cpt_en);
 513
 514         pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap,
 515                                                  reg_fields[PWM_CPT_INT_EN]);
 516         if (IS_ERR(pc->pwm_cpt_int_en))
 517                 return PTR_ERR(pc->pwm_cpt_int_en);
 518
 519         pc->pwm_cpt_int_stat = devm_regmap_field_alloc(dev, pc->regmap,
 520                                                 reg_fields[PWM_CPT_INT_STAT]);
 521         if (PTR_ERR_OR_ZERO(pc->pwm_cpt_int_stat))
 522                 return PTR_ERR(pc->pwm_cpt_int_stat);
 523
 524         return 0;
 525 }
 526
 527 static const struct regmap_config sti_pwm_regmap_config = {
 528         .reg_bits = 32,
 529         .val_bits = 32,
 530         .reg_stride = 4,
 531 };
 532
 533 static int sti_pwm_probe(struct platform_device *pdev)
 534 {
 535         struct device *dev = &pdev->dev;
 536         struct sti_pwm_compat_data *cdata;
 537         struct sti_pwm_chip *pc;
 538         struct resource *res;
 539         unsigned int i;
 540         int irq, ret;
 541
 542         pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
 543         if (!pc)
 544                 return -ENOMEM;
 545
 546         cdata = devm_kzalloc(dev, sizeof(*cdata), GFP_KERNEL);
 547         if (!cdata)
 548                 return -ENOMEM;
 549
 550         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 551
 552         pc->mmio = devm_ioremap_resource(dev, res);
 553         if (IS_ERR(pc->mmio))
 554                 return PTR_ERR(pc->mmio);
 555
 556         pc->regmap = devm_regmap_init_mmio(dev, pc->mmio,
 557                                            &sti_pwm_regmap_config);
 558         if (IS_ERR(pc->regmap))
 559                 return PTR_ERR(pc->regmap);
 560
 561         irq = platform_get_irq(pdev, 0);
 562         if (irq < 0) {
 563                 dev_err(&pdev->dev, "Failed to obtain IRQ\n");
 564                 return irq;
 565         }
 566
 567         ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt, 0,
 568                                pdev->name, pc);
 569         if (ret < 0) {
 570                 dev_err(&pdev->dev, "Failed to request IRQ\n");
 571                 return ret;
 572         }
 573
 574         /*
 575          * Setup PWM data with default values: some values could be replaced
 576          * with specific ones provided from Device Tree.
 577          */
 578         cdata->reg_fields   = &sti_pwm_regfields[0];
 579         cdata->max_prescale = 0xff;
 580         cdata->max_pwm_cnt  = 255;
 581         cdata->pwm_num_devs = 0;
 582         cdata->cpt_num_devs = 0;
 583
 584         pc->cdata = cdata;
 585         pc->dev = dev;
 586         pc->en_count = 0;
 587         mutex_init(&pc->sti_pwm_lock);
 588
 589         ret = sti_pwm_probe_dt(pc);
 590         if (ret)
 591                 return ret;
 592
 593         if (!cdata->pwm_num_devs)
 594                 goto skip_pwm;
 595
 596         pc->pwm_clk = of_clk_get_by_name(dev->of_node, "pwm");
 597         if (IS_ERR(pc->pwm_clk)) {
 598                 dev_err(dev, "failed to get PWM clock\n");
 599                 return PTR_ERR(pc->pwm_clk);
 600         }
 601
 602         ret = clk_prepare(pc->pwm_clk);
 603         if (ret) {
 604                 dev_err(dev, "failed to prepare clock\n");
 605                 return ret;
 606         }
 607
 608 skip_pwm:
 609         if (!cdata->cpt_num_devs)
 610                 goto skip_cpt;
 611
 612         pc->cpt_clk = of_clk_get_by_name(dev->of_node, "capture");
 613         if (IS_ERR(pc->cpt_clk)) {
 614                 dev_err(dev, "failed to get PWM capture clock\n");
 615                 return PTR_ERR(pc->cpt_clk);
 616         }
 617
 618         ret = clk_prepare(pc->cpt_clk);
 619         if (ret) {
 620                 dev_err(dev, "failed to prepare clock\n");
 621                 return ret;
 622         }
 623
 624 skip_cpt:
 625         pc->chip.dev = dev;
 626         pc->chip.ops = &sti_pwm_ops;
 627         pc->chip.base = -1;
 628         pc->chip.npwm = pc->cdata->pwm_num_devs;
 629         pc->chip.can_sleep = true;
 630
 631         ret = pwmchip_add(&pc->chip);
 632         if (ret < 0) {
 633                 clk_unprepare(pc->pwm_clk);
 634                 clk_unprepare(pc->cpt_clk);
 635                 return ret;
 636         }
 637
 638         for (i = 0; i < cdata->cpt_num_devs; i++) {
 639                 struct sti_cpt_ddata *ddata;
 640
 641                 ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
 642                 if (!ddata)
 643                         return -ENOMEM;
 644
 645                 init_waitqueue_head(&ddata->wait);
 646                 mutex_init(&ddata->lock);
 647
 648                 pwm_set_chip_data(&pc->chip.pwms[i], ddata);
 649         }
 650
 651         platform_set_drvdata(pdev, pc);
 652
 653         return 0;
 654 }
 655
 656 static int sti_pwm_remove(struct platform_device *pdev)
 657 {
 658         struct sti_pwm_chip *pc = platform_get_drvdata(pdev);
 659         unsigned int i;
 660
 661         for (i = 0; i < pc->cdata->pwm_num_devs; i++)
 662                 pwm_disable(&pc->chip.pwms[i]);
 663
 664         clk_unprepare(pc->pwm_clk);
 665         clk_unprepare(pc->cpt_clk);
 666
 667         return pwmchip_remove(&pc->chip);
 668 }
 669
 670 static const struct of_device_id sti_pwm_of_match[] = {
 671         { .compatible = "st,sti-pwm", },
 672         { /* sentinel */ }
 673 };
 674 MODULE_DEVICE_TABLE(of, sti_pwm_of_match);
 675
 676 static struct platform_driver sti_pwm_driver = {
 677         .driver = {
 678                 .name = "sti-pwm",
 679                 .of_match_table = sti_pwm_of_match,
 680         },
 681         .probe = sti_pwm_probe,
 682         .remove = sti_pwm_remove,
 683 };
 684 module_platform_driver(sti_pwm_driver);
 685
 686 MODULE_AUTHOR("Ajit Pal Singh <ajitpal.singh@st.com>");
 687 MODULE_DESCRIPTION("STMicroelectronics ST PWM driver");
 688 MODULE_LICENSE("GPL");