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/slab.h>
  22
  23 #define FTM_SC          0x00
  24 #define FTM_SC_CLK_MASK 0x3
  25 #define FTM_SC_CLK_SHIFT        3
  26 #define FTM_SC_CLK(c)   (((c) + 1) << FTM_SC_CLK_SHIFT)
  27 #define FTM_SC_PS_MASK  0x7
  28 #define FTM_SC_PS_SHIFT 0
  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         void __iomem *base;
  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 val, duty;
 223
 224         val = readl(fpc->base + FTM_MOD);
 225         duty = duty_ns * (val + 1);
 226         do_div(duty, period_ns);
 227
 228         return (unsigned long)duty;
 229 }
 230
 231 static int fsl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 232                           int duty_ns, int period_ns)
 233 {
 234         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 235         u32 val, period, duty;
 236
 237         mutex_lock(&fpc->lock);
 238
 239         /*
 240          * The Freescale FTM controller supports only a single period for
 241          * all PWM channels, therefore incompatible changes need to be
 242          * refused.
 243          */
 244         if (fpc->period_ns && fpc->period_ns != period_ns) {
 245                 dev_err(fpc->chip.dev,
 246                         "conflicting period requested for PWM %u\n",
 247                         pwm->hwpwm);
 248                 mutex_unlock(&fpc->lock);
 249                 return -EBUSY;
 250         }
 251
 252         if (!fpc->period_ns && duty_ns) {
 253                 period = fsl_pwm_calculate_period(fpc, period_ns);
 254                 if (!period) {
 255                         dev_err(fpc->chip.dev, "failed to calculate period\n");
 256                         mutex_unlock(&fpc->lock);
 257                         return -EINVAL;
 258                 }
 259
 260                 val = readl(fpc->base + FTM_SC);
 261                 val &= ~(FTM_SC_PS_MASK << FTM_SC_PS_SHIFT);
 262                 val |= fpc->clk_ps;
 263                 writel(val, fpc->base + FTM_SC);
 264                 writel(period - 1, fpc->base + FTM_MOD);
 265
 266                 fpc->period_ns = period_ns;
 267         }
 268
 269         mutex_unlock(&fpc->lock);
 270
 271         duty = fsl_pwm_calculate_duty(fpc, period_ns, duty_ns);
 272
 273         writel(FTM_CSC_MSB | FTM_CSC_ELSB, fpc->base + FTM_CSC(pwm->hwpwm));
 274         writel(duty, fpc->base + FTM_CV(pwm->hwpwm));
 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         val = readl(fpc->base + FTM_POL);
 287
 288         if (polarity == PWM_POLARITY_INVERSED)
 289                 val |= BIT(pwm->hwpwm);
 290         else
 291                 val &= ~BIT(pwm->hwpwm);
 292
 293         writel(val, fpc->base + FTM_POL);
 294
 295         return 0;
 296 }
 297
 298 static int fsl_counter_clock_enable(struct fsl_pwm_chip *fpc)
 299 {
 300         u32 val;
 301         int ret;
 302
 303         if (fpc->use_count != 0)
 304                 return 0;
 305
 306         /* select counter clock source */
 307         val = readl(fpc->base + FTM_SC);
 308         val &= ~(FTM_SC_CLK_MASK << FTM_SC_CLK_SHIFT);
 309         val |= FTM_SC_CLK(fpc->cnt_select);
 310         writel(val, fpc->base + FTM_SC);
 311
 312         ret = clk_prepare_enable(fpc->clk[fpc->cnt_select]);
 313         if (ret)
 314                 return ret;
 315
 316         ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 317         if (ret) {
 318                 clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
 319                 return ret;
 320         }
 321
 322         fpc->use_count++;
 323
 324         return 0;
 325 }
 326
 327 static int fsl_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 328 {
 329         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 330         u32 val;
 331         int ret;
 332
 333         mutex_lock(&fpc->lock);
 334         val = readl(fpc->base + FTM_OUTMASK);
 335         val &= ~BIT(pwm->hwpwm);
 336         writel(val, fpc->base + FTM_OUTMASK);
 337
 338         ret = fsl_counter_clock_enable(fpc);
 339         mutex_unlock(&fpc->lock);
 340
 341         return ret;
 342 }
 343
 344 static void fsl_counter_clock_disable(struct fsl_pwm_chip *fpc)
 345 {
 346         u32 val;
 347
 348         /*
 349          * already disabled, do nothing
 350          */
 351         if (fpc->use_count == 0)
 352                 return;
 353
 354         /* there are still users, so can't disable yet */
 355         if (--fpc->use_count > 0)
 356                 return;
 357
 358         /* no users left, disable PWM counter clock */
 359         val = readl(fpc->base + FTM_SC);
 360         val &= ~(FTM_SC_CLK_MASK << FTM_SC_CLK_SHIFT);
 361         writel(val, fpc->base + FTM_SC);
 362
 363         clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
 364         clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
 365 }
 366
 367 static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 368 {
 369         struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 370         u32 val;
 371
 372         mutex_lock(&fpc->lock);
 373         val = readl(fpc->base + FTM_OUTMASK);
 374         val |= BIT(pwm->hwpwm);
 375         writel(val, fpc->base + FTM_OUTMASK);
 376
 377         fsl_counter_clock_disable(fpc);
 378
 379         val = readl(fpc->base + FTM_OUTMASK);
 380
 381         if ((val & 0xFF) == 0xFF)
 382                 fpc->period_ns = 0;
 383
 384         mutex_unlock(&fpc->lock);
 385 }
 386
 387 static const struct pwm_ops fsl_pwm_ops = {
 388         .request = fsl_pwm_request,
 389         .free = fsl_pwm_free,
 390         .config = fsl_pwm_config,
 391         .set_polarity = fsl_pwm_set_polarity,
 392         .enable = fsl_pwm_enable,
 393         .disable = fsl_pwm_disable,
 394         .owner = THIS_MODULE,
 395 };
 396
 397 static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
 398 {
 399         int ret;
 400
 401         ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]);
 402         if (ret)
 403                 return ret;
 404
 405         writel(0x00, fpc->base + FTM_CNTIN);
 406         writel(0x00, fpc->base + FTM_OUTINIT);
 407         writel(0xFF, fpc->base + FTM_OUTMASK);
 408
 409         clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
 410
 411         return 0;
 412 }
 413
 414 static int fsl_pwm_probe(struct platform_device *pdev)
 415 {
 416         struct fsl_pwm_chip *fpc;
 417         struct resource *res;
 418         int ret;
 419
 420         fpc = devm_kzalloc(&pdev->dev, sizeof(*fpc), GFP_KERNEL);
 421         if (!fpc)
 422                 return -ENOMEM;
 423
 424         mutex_init(&fpc->lock);
 425
 426         fpc->chip.dev = &pdev->dev;
 427
 428         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 429         fpc->base = devm_ioremap_resource(&pdev->dev, res);
 430         if (IS_ERR(fpc->base))
 431                 return PTR_ERR(fpc->base);
 432
 433         fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
 434         if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
 435                 dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
 436                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
 437         }
 438
 439         fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
 440         if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
 441                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);
 442
 443         fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
 444         if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
 445                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);
 446
 447         fpc->clk[FSL_PWM_CLK_CNTEN] =
 448                                 devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
 449         if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
 450                 return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);
 451
 452         fpc->chip.ops = &fsl_pwm_ops;
 453         fpc->chip.of_xlate = of_pwm_xlate_with_flags;
 454         fpc->chip.of_pwm_n_cells = 3;
 455         fpc->chip.base = -1;
 456         fpc->chip.npwm = 8;
 457
 458         ret = pwmchip_add(&fpc->chip);
 459         if (ret < 0) {
 460                 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 461                 return ret;
 462         }
 463
 464         platform_set_drvdata(pdev, fpc);
 465
 466         return fsl_pwm_init(fpc);
 467 }
 468
 469 static int fsl_pwm_remove(struct platform_device *pdev)
 470 {
 471         struct fsl_pwm_chip *fpc = platform_get_drvdata(pdev);
 472
 473         return pwmchip_remove(&fpc->chip);
 474 }
 475
 476 static const struct of_device_id fsl_pwm_dt_ids[] = {
 477         { .compatible = "fsl,vf610-ftm-pwm", },
 478         { /* sentinel */ }
 479 };
 480 MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);
 481
 482 static struct platform_driver fsl_pwm_driver = {
 483         .driver = {
 484                 .name = "fsl-ftm-pwm",
 485                 .of_match_table = fsl_pwm_dt_ids,
 486         },
 487         .probe = fsl_pwm_probe,
 488         .remove = fsl_pwm_remove,
 489 };
 490 module_platform_driver(fsl_pwm_driver);
 491
 492 MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
 493 MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
 494 MODULE_ALIAS("platform:fsl-ftm-pwm");
 495 MODULE_LICENSE("GPL");