drivers/pwm/pwm-fsl-ftm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Freescale FlexTimer Module (FTM) PWM Driver
   4  *
   5  *  Copyright 2012-2013 Freescale Semiconductor, Inc.
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/err.h>
  10 #include <linux/io.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_device.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/pm.h>
  18 #include <linux/pwm.h>
  19 #include <linux/regmap.h>
  20 #include <linux/slab.h>
  21 #include <linux/fsl/ftm.h>
  22
  23 #define FTM_SC_CLK(c)   (((c) + 1) << FTM_SC_CLK_MASK_SHIFT)
  24
  25 enum fsl_pwm_clk {
  26         FSL_PWM_CLK_SYS,
  27         FSL_PWM_CLK_FIX,
  28         FSL_PWM_CLK_EXT,
  29         FSL_PWM_CLK_CNTEN,
  30         FSL_PWM_CLK_MAX
  31 };
  32
  33 struct fsl_ftm_soc {
  34         bool has_enable_bits;
  35 };
  36
  37 struct fsl_pwm_periodcfg {
  38         enum fsl_pwm_clk clk_select;
  39         unsigned int clk_ps;
  40         unsigned int mod_period;
  41 };
  42
  43 struct fsl_pwm_chip {
  44         struct pwm_chip chip;
  45         struct mutex lock;
  46         struct regmap *regmap;
  47
  48         /* This value is valid iff a pwm is running */
  49         struct fsl_pwm_periodcfg period;
  50
  51         struct clk *ipg_clk;
  52         struct clk *clk[FSL_PWM_CLK_MAX];
  53
  54         const struct fsl_ftm_soc *soc;
  55 };
  56
  57 static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
  58 {
  59         return container_of(chip, struct fsl_pwm_chip, chip);
  60 }
  61
  62 static void ftm_clear_write_protection(struct fsl_pwm_chip *fpc)
  63 {
  64         u32 val;
  65
  66         regmap_read(fpc->regmap, FTM_FMS, &val);
  67         if (val & FTM_FMS_WPEN)
  68                 regmap_update_bits(fpc->regmap, FTM_MODE, FTM_MODE_WPDIS,
  69                                    FTM_MODE_WPDIS);
  70 }
  71
  72 static void ftm_set_write_protection(struct fsl_pwm_chip *fpc)
  73 {
  74         regmap_update_bits(fpc->regmap, FTM_FMS, FTM_FMS_WPEN, FTM_FMS_WPEN);
  75 }
  76
  77 static bool fsl_pwm_periodcfg_are_equal(const struct fsl_pwm_periodcfg *a,
  78                                         const struct fsl_pwm_periodcfg *b)
  79 {
  80         if (a->clk_select != b->clk_select)
  81                 return false;
  82         if (a->clk_ps != b->clk_ps)
  83                 return false;
  84         if (a->mod_period != b->mod_period)
  85                 return false;
  86         return true;
  87 }
  88
  89 static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  90 {
  91         int ret;
  92         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
  93
  94         ret = clk_prepare_enable(fpc->ipg_clk);
  95         if (!ret && fpc->soc->has_enable_bits) {
  96                 mutex_lock(&fpc->lock);
  97                 regmap_update_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16),
  98                                    BIT(pwm->hwpwm + 16));
  99                 mutex_unlock(&fpc->lock);
 100         }
 101
 102         return ret;
 103 }
 104
 105 static void fsl_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 106 {
 107         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 108
 109         if (fpc->soc->has_enable_bits) {
 110                 mutex_lock(&fpc->lock);
 111                 regmap_update_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16),
 112                                    0);
 113                 mutex_unlock(&fpc->lock);
 114         }
 115
 116         clk_disable_unprepare(fpc->ipg_clk);
 117 }
 118
 119 static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
 120                                           unsigned int ticks)
 121 {
 122         unsigned long rate;
 123         unsigned long long exval;
 124
 125         rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
 126         exval = ticks;
 127         exval *= 1000000000UL;
 128         do_div(exval, rate >> fpc->period.clk_ps);
 129         return exval;
 130 }
 131
 132 static bool fsl_pwm_calculate_period_clk(struct fsl_pwm_chip *fpc,
 133                                          unsigned int period_ns,
 134                                          enum fsl_pwm_clk index,
 135                                          struct fsl_pwm_periodcfg *periodcfg
 136                                          )
 137 {
 138         unsigned long long c;
 139         unsigned int ps;
 140
 141         c = clk_get_rate(fpc->clk[index]);
 142         c = c * period_ns;
 143         do_div(c, 1000000000UL);
 144
 145         if (c == 0)
 146                 return false;
 147
 148         for (ps = 0; ps < 8 ; ++ps, c >>= 1) {
 149                 if (c <= 0x10000) {
 150                         periodcfg->clk_select = index;
 151                         periodcfg->clk_ps = ps;
 152                         periodcfg->mod_period = c - 1;
 153                         return true;
 154                 }
 155         }
 156         return false;
 157 }
 158
 159 static bool fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
 160                                      unsigned int period_ns,
 161                                      struct fsl_pwm_periodcfg *periodcfg)
 162 {
 163         enum fsl_pwm_clk m0, m1;
 164         unsigned long fix_rate, ext_rate;
 165         bool ret;
 166
 167         ret = fsl_pwm_calculate_period_clk(fpc, period_ns, FSL_PWM_CLK_SYS,
 168                                            periodcfg);
 169         if (ret)
 170                 return true;
 171
 172         fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
 173         ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);
 174
 175         if (fix_rate > ext_rate) {
 176                 m0 = FSL_PWM_CLK_FIX;
 177                 m1 = FSL_PWM_CLK_EXT;
 178         } else {
 179                 m0 = FSL_PWM_CLK_EXT;
 180                 m1 = FSL_PWM_CLK_FIX;
 181         }
 182
 183         ret = fsl_pwm_calculate_period_clk(fpc, period_ns, m0, periodcfg);
 184         if (ret)
 185                 return true;
 186
 187         return fsl_pwm_calculate_period_clk(fpc, period_ns, m1, periodcfg);
 188 }
 189
 190 static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
 191                                            unsigned int duty_ns)
 192 {
 193         unsigned long long duty;
 194
 195         unsigned int period = fpc->period.mod_period + 1;
 196         unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);
 197
 198         duty = (unsigned long long)duty_ns * period;
 199         do_div(duty, period_ns);
 200
 201         return (unsigned int)duty;
 202 }
 203
 204 static bool fsl_pwm_is_any_pwm_enabled(struct fsl_pwm_chip *fpc,
 205                                        struct pwm_device *pwm)
 206 {
 207         u32 val;
 208
 209         regmap_read(fpc->regmap, FTM_OUTMASK, &val);
 210         if (~val & 0xFF)
 211                 return true;
 212         else
 213                 return false;
 214 }
 215
 216 static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
 217                                          struct pwm_device *pwm)
 218 {
 219         u32 val;
 220
 221         regmap_read(fpc->regmap, FTM_OUTMASK, &val);
 222         if (~(val | BIT(pwm->hwpwm)) & 0xFF)
 223                 return true;
 224         else
 225                 return false;
 226 }
 227
 228 static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
 229                                 struct pwm_device *pwm,
 230                                 const struct pwm_state *newstate)
 231 {
 232         unsigned int duty;
 233         u32 reg_polarity;
 234
 235         struct fsl_pwm_periodcfg periodcfg;
 236         bool do_write_period = false;
 237
 238         if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
 239                 dev_err(fpc->chip.dev, "failed to calculate new period\n");
 240                 return -EINVAL;
 241         }
 242
 243         if (!fsl_pwm_is_any_pwm_enabled(fpc, pwm))
 244                 do_write_period = true;
 245         /*
 246          * The Freescale FTM controller supports only a single period for
 247          * all PWM channels, therefore verify if the newly computed period
 248          * is different than the current period being used. In such case
 249          * we allow to change the period only if no other pwm is running.
 250          */
 251         else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
 252                 if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
 253                         dev_err(fpc->chip.dev,
 254                                 "Cannot change period for PWM %u, disable other PWMs first\n",
 255                                 pwm->hwpwm);
 256                         return -EBUSY;
 257                 }
 258                 if (fpc->period.clk_select != periodcfg.clk_select) {
 259                         int ret;
 260                         enum fsl_pwm_clk oldclk = fpc->period.clk_select;
 261                         enum fsl_pwm_clk newclk = periodcfg.clk_select;
 262
 263                         ret = clk_prepare_enable(fpc->clk[newclk]);
 264                         if (ret)
 265                                 return ret;
 266                         clk_disable_unprepare(fpc->clk[oldclk]);
 267                 }
 268                 do_write_period = true;
 269         }
 270
 271         ftm_clear_write_protection(fpc);
 272
 273         if (do_write_period) {
 274                 regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
 275                                    FTM_SC_CLK(periodcfg.clk_select));
 276                 regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
 277                                    periodcfg.clk_ps);
 278                 regmap_write(fpc->regmap, FTM_MOD, periodcfg.mod_period);
 279
 280                 fpc->period = periodcfg;
 281         }
 282
 283         duty = fsl_pwm_calculate_duty(fpc, newstate->duty_cycle);
 284
 285         regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
 286                      FTM_CSC_MSB | FTM_CSC_ELSB);
 287         regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);
 288
 289         reg_polarity = 0;
 290         if (newstate->polarity == PWM_POLARITY_INVERSED)
 291                 reg_polarity = BIT(pwm->hwpwm);
 292
 293         regmap_update_bits(fpc->regmap, FTM_POL, BIT(pwm->hwpwm), reg_polarity);
 294
 295         ftm_set_write_protection(fpc);
 296
 297         return 0;
 298 }
 299
 300 static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 301                          const struct pwm_state *newstate)
 302 {
 303         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 304         struct pwm_state *oldstate = &pwm->state;
 305         int ret = 0;
 306
 307         /*
 308          * oldstate to newstate : action
 309          *
 310          * disabled to disabled : ignore
 311          * enabled to disabled : disable
 312          * enabled to enabled : update settings
 313          * disabled to enabled : update settings + enable
 314          */
 315
 316         mutex_lock(&fpc->lock);
 317
 318         if (!newstate->enabled) {
 319                 if (oldstate->enabled) {
 320                         regmap_update_bits(fpc->regmap, FTM_OUTMASK,
 321                                            BIT(pwm->hwpwm), BIT(pwm->hwpwm));
 322                         clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
 323                         clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
 324                 }
 325
 326                 goto end_mutex;
 327         }
 328
 329         ret = fsl_pwm_apply_config(fpc, pwm, newstate);
 330         if (ret)
 331                 goto end_mutex;
 332
 333         /* check if need to enable */
 334         if (!oldstate->enabled) {
 335                 ret = clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
 336                 if (ret)
 337                         goto end_mutex;
 338
 339                 ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 340                 if (ret) {
 341                         clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
 342                         goto end_mutex;
 343                 }
 344
 345                 regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
 346                                    0);
 347         }
 348
 349 end_mutex:
 350         mutex_unlock(&fpc->lock);
 351         return ret;
 352 }
 353
 354 static const struct pwm_ops fsl_pwm_ops = {
 355         .request = fsl_pwm_request,
 356         .free = fsl_pwm_free,
 357         .apply = fsl_pwm_apply,
 358         .owner = THIS_MODULE,
 359 };
 360
 361 static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
 362 {
 363         int ret;
 364
 365         ret = clk_prepare_enable(fpc->ipg_clk);
 366         if (ret)
 367                 return ret;
 368
 369         regmap_write(fpc->regmap, FTM_CNTIN, 0x00);
 370         regmap_write(fpc->regmap, FTM_OUTINIT, 0x00);
 371         regmap_write(fpc->regmap, FTM_OUTMASK, 0xFF);
 372
 373         clk_disable_unprepare(fpc->ipg_clk);
 374
 375         return 0;
 376 }
 377
 378 static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
 379 {
 380         switch (reg) {
 381         case FTM_FMS:
 382         case FTM_MODE:
 383         case FTM_CNT:
 384                 return true;
 385         }
 386         return false;
 387 }
 388
 389 static const struct regmap_config fsl_pwm_regmap_config = {
 390         .reg_bits = 32,
 391         .reg_stride = 4,
 392         .val_bits = 32,
 393
 394         .max_register = FTM_PWMLOAD,
 395         .volatile_reg = fsl_pwm_volatile_reg,
 396         .cache_type = REGCACHE_FLAT,
 397 };
 398
 399 static int fsl_pwm_probe(struct platform_device *pdev)
 400 {
 401         struct fsl_pwm_chip *fpc;
 402         void __iomem *base;
 403         int ret;
 404
 405         fpc = devm_kzalloc(&pdev->dev, sizeof(*fpc), GFP_KERNEL);
 406         if (!fpc)
 407                 return -ENOMEM;
 408
 409         mutex_init(&fpc->lock);
 410
 411         fpc->soc = of_device_get_match_data(&pdev->dev);
 412         fpc->chip.dev = &pdev->dev;
 413
 414         base = devm_platform_ioremap_resource(pdev, 0);
 415         if (IS_ERR(base))
 416                 return PTR_ERR(base);
 417
 418         fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "ftm_sys", base,
 419                                                 &fsl_pwm_regmap_config);
 420         if (IS_ERR(fpc->regmap)) {
 421                 dev_err(&pdev->dev, "regmap init failed\n");
 422                 return PTR_ERR(fpc->regmap);
 423         }
 424
 425         fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
 426         if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
 427                 dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
 428                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
 429         }
 430
 431         fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
 432         if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
 433                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);
 434
 435         fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
 436         if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
 437                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);
 438
 439         fpc->clk[FSL_PWM_CLK_CNTEN] =
 440                                 devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
 441         if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
 442                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);
 443
 444         /*
 445          * ipg_clk is the interface clock for the IP. If not provided, use the
 446          * ftm_sys clock as the default.
 447          */
 448         fpc->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
 449         if (IS_ERR(fpc->ipg_clk))
 450                 fpc->ipg_clk = fpc->clk[FSL_PWM_CLK_SYS];
 451
 452
 453         fpc->chip.ops = &fsl_pwm_ops;
 454         fpc->chip.of_xlate = of_pwm_xlate_with_flags;
 455         fpc->chip.of_pwm_n_cells = 3;
 456         fpc->chip.base = -1;
 457         fpc->chip.npwm = 8;
 458
 459         ret = pwmchip_add(&fpc->chip);
 460         if (ret < 0) {
 461                 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 462                 return ret;
 463         }
 464
 465         platform_set_drvdata(pdev, fpc);
 466
 467         return fsl_pwm_init(fpc);
 468 }
 469
 470 static int fsl_pwm_remove(struct platform_device *pdev)
 471 {
 472         struct fsl_pwm_chip *fpc = platform_get_drvdata(pdev);
 473
 474         return pwmchip_remove(&fpc->chip);
 475 }
 476
 477 #ifdef CONFIG_PM_SLEEP
 478 static int fsl_pwm_suspend(struct device *dev)
 479 {
 480         struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
 481         int i;
 482
 483         regcache_cache_only(fpc->regmap, true);
 484         regcache_mark_dirty(fpc->regmap);
 485
 486         for (i = 0; i < fpc->chip.npwm; i++) {
 487                 struct pwm_device *pwm = &fpc->chip.pwms[i];
 488
 489                 if (!test_bit(PWMF_REQUESTED, &pwm->flags))
 490                         continue;
 491
 492                 clk_disable_unprepare(fpc->ipg_clk);
 493
 494                 if (!pwm_is_enabled(pwm))
 495                         continue;
 496
 497                 clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
 498                 clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
 499         }
 500
 501         return 0;
 502 }
 503
 504 static int fsl_pwm_resume(struct device *dev)
 505 {
 506         struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
 507         int i;
 508
 509         for (i = 0; i < fpc->chip.npwm; i++) {
 510                 struct pwm_device *pwm = &fpc->chip.pwms[i];
 511
 512                 if (!test_bit(PWMF_REQUESTED, &pwm->flags))
 513                         continue;
 514
 515                 clk_prepare_enable(fpc->ipg_clk);
 516
 517                 if (!pwm_is_enabled(pwm))
 518                         continue;
 519
 520                 clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
 521                 clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 522         }
 523
 524         /* restore all registers from cache */
 525         regcache_cache_only(fpc->regmap, false);
 526         regcache_sync(fpc->regmap);
 527
 528         return 0;
 529 }
 530 #endif
 531
 532 static const struct dev_pm_ops fsl_pwm_pm_ops = {
 533         SET_SYSTEM_SLEEP_PM_OPS(fsl_pwm_suspend, fsl_pwm_resume)
 534 };
 535
 536 static const struct fsl_ftm_soc vf610_ftm_pwm = {
 537         .has_enable_bits = false,
 538 };
 539
 540 static const struct fsl_ftm_soc imx8qm_ftm_pwm = {
 541         .has_enable_bits = true,
 542 };
 543
 544 static const struct of_device_id fsl_pwm_dt_ids[] = {
 545         { .compatible = "fsl,vf610-ftm-pwm", .data = &vf610_ftm_pwm },
 546         { .compatible = "fsl,imx8qm-ftm-pwm", .data = &imx8qm_ftm_pwm },
 547         { /* sentinel */ }
 548 };
 549 MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);
 550
 551 static struct platform_driver fsl_pwm_driver = {
 552         .driver = {
 553                 .name = "fsl-ftm-pwm",
 554                 .of_match_table = fsl_pwm_dt_ids,
 555                 .pm = &fsl_pwm_pm_ops,
 556         },
 557         .probe = fsl_pwm_probe,
 558         .remove = fsl_pwm_remove,
 559 };
 560 module_platform_driver(fsl_pwm_driver);
 561
 562 MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
 563 MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
 564 MODULE_ALIAS("platform:fsl-ftm-pwm");
 565 MODULE_LICENSE("GPL");