drivers/pwm/pwm-fsl-ftm.c

   1 /*
   2  *  Freescale FlexTimer Module (FTM) PWM Driver
   3  *
   4  *  Copyright 2012-2013 Freescale Semiconductor, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/err.h>
  14 #include <linux/io.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/mutex.h>
  18 #include <linux/of_address.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/pwm.h>
  21 #include <linux/regmap.h>
  22 #include <linux/slab.h>
  23
  24 #define FTM_SC          0x00
  25 #define FTM_SC_CLK_MASK_SHIFT   3
  26 #define FTM_SC_CLK_MASK (3 << FTM_SC_CLK_MASK_SHIFT)
  27 #define FTM_SC_CLK(c)   (((c) + 1) << FTM_SC_CLK_MASK_SHIFT)
  28 #define FTM_SC_PS_MASK  0x7
  29
  30 #define FTM_CNT         0x04
  31 #define FTM_MOD         0x08
  32
  33 #define FTM_CSC_BASE    0x0C
  34 #define FTM_CSC_MSB     BIT(5)
  35 #define FTM_CSC_MSA     BIT(4)
  36 #define FTM_CSC_ELSB    BIT(3)
  37 #define FTM_CSC_ELSA    BIT(2)
  38 #define FTM_CSC(_channel)       (FTM_CSC_BASE + ((_channel) * 8))
  39
  40 #define FTM_CV_BASE     0x10
  41 #define FTM_CV(_channel)        (FTM_CV_BASE + ((_channel) * 8))
  42
  43 #define FTM_CNTIN       0x4C
  44 #define FTM_STATUS      0x50
  45
  46 #define FTM_MODE        0x54
  47 #define FTM_MODE_FTMEN  BIT(0)
  48 #define FTM_MODE_INIT   BIT(2)
  49 #define FTM_MODE_PWMSYNC        BIT(3)
  50
  51 #define FTM_SYNC        0x58
  52 #define FTM_OUTINIT     0x5C
  53 #define FTM_OUTMASK     0x60
  54 #define FTM_COMBINE     0x64
  55 #define FTM_DEADTIME    0x68
  56 #define FTM_EXTTRIG     0x6C
  57 #define FTM_POL         0x70
  58 #define FTM_FMS         0x74
  59 #define FTM_FILTER      0x78
  60 #define FTM_FLTCTRL     0x7C
  61 #define FTM_QDCTRL      0x80
  62 #define FTM_CONF        0x84
  63 #define FTM_FLTPOL      0x88
  64 #define FTM_SYNCONF     0x8C
  65 #define FTM_INVCTRL     0x90
  66 #define FTM_SWOCTRL     0x94
  67 #define FTM_PWMLOAD     0x98
  68
  69 enum fsl_pwm_clk {
  70         FSL_PWM_CLK_SYS,
  71         FSL_PWM_CLK_FIX,
  72         FSL_PWM_CLK_EXT,
  73         FSL_PWM_CLK_CNTEN,
  74         FSL_PWM_CLK_MAX
  75 };
  76
  77 struct fsl_pwm_chip {
  78         struct pwm_chip chip;
  79
  80         struct mutex lock;
  81
  82         unsigned int use_count;
  83         unsigned int cnt_select;
  84         unsigned int clk_ps;
  85
  86         struct regmap *regmap;
  87
  88         int period_ns;
  89
  90         struct clk *clk[FSL_PWM_CLK_MAX];
  91 };
  92
  93 static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
  94 {
  95         return container_of(chip, struct fsl_pwm_chip, chip);
  96 }
  97
  98 static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  99 {
 100         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 101
 102         return clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]);
 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         clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
 110 }
 111
 112 static int fsl_pwm_calculate_default_ps(struct fsl_pwm_chip *fpc,
 113                                         enum fsl_pwm_clk index)
 114 {
 115         unsigned long sys_rate, cnt_rate;
 116         unsigned long long ratio;
 117
 118         sys_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_SYS]);
 119         if (!sys_rate)
 120                 return -EINVAL;
 121
 122         cnt_rate = clk_get_rate(fpc->clk[fpc->cnt_select]);
 123         if (!cnt_rate)
 124                 return -EINVAL;
 125
 126         switch (index) {
 127         case FSL_PWM_CLK_SYS:
 128                 fpc->clk_ps = 1;
 129                 break;
 130         case FSL_PWM_CLK_FIX:
 131                 ratio = 2 * cnt_rate - 1;
 132                 do_div(ratio, sys_rate);
 133                 fpc->clk_ps = ratio;
 134                 break;
 135         case FSL_PWM_CLK_EXT:
 136                 ratio = 4 * cnt_rate - 1;
 137                 do_div(ratio, sys_rate);
 138                 fpc->clk_ps = ratio;
 139                 break;
 140         default:
 141                 return -EINVAL;
 142         }
 143
 144         return 0;
 145 }
 146
 147 static unsigned long fsl_pwm_calculate_cycles(struct fsl_pwm_chip *fpc,
 148                                               unsigned long period_ns)
 149 {
 150         unsigned long long c, c0;
 151
 152         c = clk_get_rate(fpc->clk[fpc->cnt_select]);
 153         c = c * period_ns;
 154         do_div(c, 1000000000UL);
 155
 156         do {
 157                 c0 = c;
 158                 do_div(c0, (1 << fpc->clk_ps));
 159                 if (c0 <= 0xFFFF)
 160                         return (unsigned long)c0;
 161         } while (++fpc->clk_ps < 8);
 162
 163         return 0;
 164 }
 165
 166 static unsigned long fsl_pwm_calculate_period_cycles(struct fsl_pwm_chip *fpc,
 167                                                      unsigned long period_ns,
 168                                                      enum fsl_pwm_clk index)
 169 {
 170         int ret;
 171
 172         ret = fsl_pwm_calculate_default_ps(fpc, index);
 173         if (ret) {
 174                 dev_err(fpc->chip.dev,
 175                         "failed to calculate default prescaler: %d\n",
 176                         ret);
 177                 return 0;
 178         }
 179
 180         return fsl_pwm_calculate_cycles(fpc, period_ns);
 181 }
 182
 183 static unsigned long fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
 184                                               unsigned long period_ns)
 185 {
 186         enum fsl_pwm_clk m0, m1;
 187         unsigned long fix_rate, ext_rate, cycles;
 188
 189         cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns,
 190                         FSL_PWM_CLK_SYS);
 191         if (cycles) {
 192                 fpc->cnt_select = FSL_PWM_CLK_SYS;
 193                 return cycles;
 194         }
 195
 196         fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
 197         ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);
 198
 199         if (fix_rate > ext_rate) {
 200                 m0 = FSL_PWM_CLK_FIX;
 201                 m1 = FSL_PWM_CLK_EXT;
 202         } else {
 203                 m0 = FSL_PWM_CLK_EXT;
 204                 m1 = FSL_PWM_CLK_FIX;
 205         }
 206
 207         cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns, m0);
 208         if (cycles) {
 209                 fpc->cnt_select = m0;
 210                 return cycles;
 211         }
 212
 213         fpc->cnt_select = m1;
 214
 215         return fsl_pwm_calculate_period_cycles(fpc, period_ns, m1);
 216 }
 217
 218 static unsigned long fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
 219                                             unsigned long period_ns,
 220                                             unsigned long duty_ns)
 221 {
 222         unsigned long long duty;
 223         u32 val;
 224
 225         regmap_read(fpc->regmap, FTM_MOD, &val);
 226         duty = (unsigned long long)duty_ns * (val + 1);
 227         do_div(duty, period_ns);
 228
 229         return (unsigned long)duty;
 230 }
 231
 232 static int fsl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 233                           int duty_ns, int period_ns)
 234 {
 235         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 236         u32 period, duty;
 237
 238         mutex_lock(&fpc->lock);
 239
 240         /*
 241          * The Freescale FTM controller supports only a single period for
 242          * all PWM channels, therefore incompatible changes need to be
 243          * refused.
 244          */
 245         if (fpc->period_ns && fpc->period_ns != period_ns) {
 246                 dev_err(fpc->chip.dev,
 247                         "conflicting period requested for PWM %u\n",
 248                         pwm->hwpwm);
 249                 mutex_unlock(&fpc->lock);
 250                 return -EBUSY;
 251         }
 252
 253         if (!fpc->period_ns && duty_ns) {
 254                 period = fsl_pwm_calculate_period(fpc, period_ns);
 255                 if (!period) {
 256                         dev_err(fpc->chip.dev, "failed to calculate period\n");
 257                         mutex_unlock(&fpc->lock);
 258                         return -EINVAL;
 259                 }
 260
 261                 regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
 262                                    fpc->clk_ps);
 263                 regmap_write(fpc->regmap, FTM_MOD, period - 1);
 264
 265                 fpc->period_ns = period_ns;
 266         }
 267
 268         mutex_unlock(&fpc->lock);
 269
 270         duty = fsl_pwm_calculate_duty(fpc, period_ns, duty_ns);
 271
 272         regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
 273                      FTM_CSC_MSB | FTM_CSC_ELSB);
 274         regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);
 275
 276         return 0;
 277 }
 278
 279 static int fsl_pwm_set_polarity(struct pwm_chip *chip,
 280                                 struct pwm_device *pwm,
 281                                 enum pwm_polarity polarity)
 282 {
 283         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 284         u32 val;
 285
 286         regmap_read(fpc->regmap, FTM_POL, &val);
 287
 288         if (polarity == PWM_POLARITY_INVERSED)
 289                 val |= BIT(pwm->hwpwm);
 290         else
 291                 val &= ~BIT(pwm->hwpwm);
 292
 293         regmap_write(fpc->regmap, FTM_POL, val);
 294
 295         return 0;
 296 }
 297
 298 static int fsl_counter_clock_enable(struct fsl_pwm_chip *fpc)
 299 {
 300         int ret;
 301
 302         if (fpc->use_count++ != 0)
 303                 return 0;
 304
 305         /* select counter clock source */
 306         regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
 307                            FTM_SC_CLK(fpc->cnt_select));
 308
 309         ret = clk_prepare_enable(fpc->clk[fpc->cnt_select]);
 310         if (ret)
 311                 return ret;
 312
 313         ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 314         if (ret) {
 315                 clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
 316                 return ret;
 317         }
 318
 319         return 0;
 320 }
 321
 322 static int fsl_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 323 {
 324         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 325         int ret;
 326
 327         mutex_lock(&fpc->lock);
 328         regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm), 0);
 329
 330         ret = fsl_counter_clock_enable(fpc);
 331         mutex_unlock(&fpc->lock);
 332
 333         return ret;
 334 }
 335
 336 static void fsl_counter_clock_disable(struct fsl_pwm_chip *fpc)
 337 {
 338         /*
 339          * already disabled, do nothing
 340          */
 341         if (fpc->use_count == 0)
 342                 return;
 343
 344         /* there are still users, so can't disable yet */
 345         if (--fpc->use_count > 0)
 346                 return;
 347
 348         /* no users left, disable PWM counter clock */
 349         regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK, 0);
 350
 351         clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
 352         clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
 353 }
 354
 355 static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 356 {
 357         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 358         u32 val;
 359
 360         mutex_lock(&fpc->lock);
 361         regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
 362                            BIT(pwm->hwpwm));
 363
 364         fsl_counter_clock_disable(fpc);
 365
 366         regmap_read(fpc->regmap, FTM_OUTMASK, &val);
 367         if ((val & 0xFF) == 0xFF)
 368                 fpc->period_ns = 0;
 369
 370         mutex_unlock(&fpc->lock);
 371 }
 372
 373 static const struct pwm_ops fsl_pwm_ops = {
 374         .request = fsl_pwm_request,
 375         .free = fsl_pwm_free,
 376         .config = fsl_pwm_config,
 377         .set_polarity = fsl_pwm_set_polarity,
 378         .enable = fsl_pwm_enable,
 379         .disable = fsl_pwm_disable,
 380         .owner = THIS_MODULE,
 381 };
 382
 383 static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
 384 {
 385         int ret;
 386
 387         ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]);
 388         if (ret)
 389                 return ret;
 390
 391         regmap_write(fpc->regmap, FTM_CNTIN, 0x00);
 392         regmap_write(fpc->regmap, FTM_OUTINIT, 0x00);
 393         regmap_write(fpc->regmap, FTM_OUTMASK, 0xFF);
 394
 395         clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
 396
 397         return 0;
 398 }
 399
 400 static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
 401 {
 402         switch (reg) {
 403         case FTM_CNT:
 404                 return true;
 405         }
 406         return false;
 407 }
 408
 409 static const struct regmap_config fsl_pwm_regmap_config = {
 410         .reg_bits = 32,
 411         .reg_stride = 4,
 412         .val_bits = 32,
 413
 414         .max_register = FTM_PWMLOAD,
 415         .volatile_reg = fsl_pwm_volatile_reg,
 416         .cache_type = REGCACHE_RBTREE,
 417 };
 418
 419 static int fsl_pwm_probe(struct platform_device *pdev)
 420 {
 421         struct fsl_pwm_chip *fpc;
 422         struct resource *res;
 423         void __iomem *base;
 424         int ret;
 425
 426         fpc = devm_kzalloc(&pdev->dev, sizeof(*fpc), GFP_KERNEL);
 427         if (!fpc)
 428                 return -ENOMEM;
 429
 430         mutex_init(&fpc->lock);
 431
 432         fpc->chip.dev = &pdev->dev;
 433
 434         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 435         base = devm_ioremap_resource(&pdev->dev, res);
 436         if (IS_ERR(base))
 437                 return PTR_ERR(base);
 438
 439         fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
 440                                                 &fsl_pwm_regmap_config);
 441         if (IS_ERR(fpc->regmap)) {
 442                 dev_err(&pdev->dev, "regmap init failed\n");
 443                 return PTR_ERR(fpc->regmap);
 444         }
 445
 446         fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
 447         if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
 448                 dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
 449                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
 450         }
 451
 452         fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
 453         if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
 454                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);
 455
 456         fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
 457         if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
 458                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);
 459
 460         fpc->clk[FSL_PWM_CLK_CNTEN] =
 461                                 devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
 462         if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
 463                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);
 464
 465         fpc->chip.ops = &fsl_pwm_ops;
 466         fpc->chip.of_xlate = of_pwm_xlate_with_flags;
 467         fpc->chip.of_pwm_n_cells = 3;
 468         fpc->chip.base = -1;
 469         fpc->chip.npwm = 8;
 470         fpc->chip.can_sleep = true;
 471
 472         ret = pwmchip_add(&fpc->chip);
 473         if (ret < 0) {
 474                 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 475                 return ret;
 476         }
 477
 478         platform_set_drvdata(pdev, fpc);
 479
 480         return fsl_pwm_init(fpc);
 481 }
 482
 483 static int fsl_pwm_remove(struct platform_device *pdev)
 484 {
 485         struct fsl_pwm_chip *fpc = platform_get_drvdata(pdev);
 486
 487         return pwmchip_remove(&fpc->chip);
 488 }
 489
 490 static const struct of_device_id fsl_pwm_dt_ids[] = {
 491         { .compatible = "fsl,vf610-ftm-pwm", },
 492         { /* sentinel */ }
 493 };
 494 MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);
 495
 496 static struct platform_driver fsl_pwm_driver = {
 497         .driver = {
 498                 .name = "fsl-ftm-pwm",
 499                 .of_match_table = fsl_pwm_dt_ids,
 500         },
 501         .probe = fsl_pwm_probe,
 502         .remove = fsl_pwm_remove,
 503 };
 504 module_platform_driver(fsl_pwm_driver);
 505
 506 MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
 507 MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
 508 MODULE_ALIAS("platform:fsl-ftm-pwm");
 509 MODULE_LICENSE("GPL");