drivers/pwm/pwm-atmel-tcb.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) Overkiz SAS 2012
   4  *
   5  * Author: Boris BREZILLON <b.brezillon@overkiz.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/clocksource.h>
  11 #include <linux/clockchips.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/irq.h>
  14
  15 #include <linux/clk.h>
  16 #include <linux/err.h>
  17 #include <linux/ioport.h>
  18 #include <linux/io.h>
  19 #include <linux/mfd/syscon.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/pwm.h>
  22 #include <linux/of.h>
  23 #include <linux/regmap.h>
  24 #include <linux/slab.h>
  25 #include <soc/at91/atmel_tcb.h>
  26
  27 #define NPWM    2
  28
  29 #define ATMEL_TC_ACMR_MASK      (ATMEL_TC_ACPA | ATMEL_TC_ACPC |        \
  30                                  ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG)
  31
  32 #define ATMEL_TC_BCMR_MASK      (ATMEL_TC_BCPB | ATMEL_TC_BCPC |        \
  33                                  ATMEL_TC_BEEVT | ATMEL_TC_BSWTRG)
  34
  35 struct atmel_tcb_pwm_device {
  36         unsigned div;                   /* PWM clock divider */
  37         unsigned duty;                  /* PWM duty expressed in clk cycles */
  38         unsigned period;                /* PWM period expressed in clk cycles */
  39 };
  40
  41 struct atmel_tcb_channel {
  42         u32 enabled;
  43         u32 cmr;
  44         u32 ra;
  45         u32 rb;
  46         u32 rc;
  47 };
  48
  49 struct atmel_tcb_pwm_chip {
  50         spinlock_t lock;
  51         u8 channel;
  52         u8 width;
  53         struct regmap *regmap;
  54         struct clk *clk;
  55         struct clk *gclk;
  56         struct clk *slow_clk;
  57         struct atmel_tcb_pwm_device pwms[NPWM];
  58         struct atmel_tcb_channel bkup;
  59 };
  60
  61 static const u8 atmel_tcb_divisors[] = { 2, 8, 32, 128, 0, };
  62
  63 static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip)
  64 {
  65         return pwmchip_get_drvdata(chip);
  66 }
  67
  68 static int atmel_tcb_pwm_request(struct pwm_chip *chip,
  69                                  struct pwm_device *pwm)
  70 {
  71         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
  72         struct atmel_tcb_pwm_device *tcbpwm = &tcbpwmc->pwms[pwm->hwpwm];
  73         unsigned cmr;
  74         int ret;
  75
  76         ret = clk_prepare_enable(tcbpwmc->clk);
  77         if (ret)
  78                 return ret;
  79
  80         tcbpwm->duty = 0;
  81         tcbpwm->period = 0;
  82         tcbpwm->div = 0;
  83
  84         guard(spinlock)(&tcbpwmc->lock);
  85
  86         regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);
  87         /*
  88          * Get init config from Timer Counter registers if
  89          * Timer Counter is already configured as a PWM generator.
  90          */
  91         if (cmr & ATMEL_TC_WAVE) {
  92                 if (pwm->hwpwm == 0)
  93                         regmap_read(tcbpwmc->regmap,
  94                                     ATMEL_TC_REG(tcbpwmc->channel, RA),
  95                                     &tcbpwm->duty);
  96                 else
  97                         regmap_read(tcbpwmc->regmap,
  98                                     ATMEL_TC_REG(tcbpwmc->channel, RB),
  99                                     &tcbpwm->duty);
 100
 101                 tcbpwm->div = cmr & ATMEL_TC_TCCLKS;
 102                 regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, RC),
 103                             &tcbpwm->period);
 104                 cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK |
 105                         ATMEL_TC_BCMR_MASK);
 106         } else
 107                 cmr = 0;
 108
 109         cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0;
 110         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);
 111
 112         return 0;
 113 }
 114
 115 static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 116 {
 117         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 118
 119         clk_disable_unprepare(tcbpwmc->clk);
 120 }
 121
 122 static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm,
 123                                   enum pwm_polarity polarity)
 124 {
 125         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 126         struct atmel_tcb_pwm_device *tcbpwm = &tcbpwmc->pwms[pwm->hwpwm];
 127         unsigned cmr;
 128
 129         /*
 130          * If duty is 0 the timer will be stopped and we have to
 131          * configure the output correctly on software trigger:
 132          *  - set output to high if PWM_POLARITY_INVERSED
 133          *  - set output to low if PWM_POLARITY_NORMAL
 134          *
 135          * This is why we're reverting polarity in this case.
 136          */
 137         if (tcbpwm->duty == 0)
 138                 polarity = !polarity;
 139
 140         regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);
 141
 142         /* flush old setting and set the new one */
 143         if (pwm->hwpwm == 0) {
 144                 cmr &= ~ATMEL_TC_ACMR_MASK;
 145                 if (polarity == PWM_POLARITY_INVERSED)
 146                         cmr |= ATMEL_TC_ASWTRG_CLEAR;
 147                 else
 148                         cmr |= ATMEL_TC_ASWTRG_SET;
 149         } else {
 150                 cmr &= ~ATMEL_TC_BCMR_MASK;
 151                 if (polarity == PWM_POLARITY_INVERSED)
 152                         cmr |= ATMEL_TC_BSWTRG_CLEAR;
 153                 else
 154                         cmr |= ATMEL_TC_BSWTRG_SET;
 155         }
 156
 157         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);
 158
 159         /*
 160          * Use software trigger to apply the new setting.
 161          * If both PWM devices in this group are disabled we stop the clock.
 162          */
 163         if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC))) {
 164                 regmap_write(tcbpwmc->regmap,
 165                              ATMEL_TC_REG(tcbpwmc->channel, CCR),
 166                              ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS);
 167                 tcbpwmc->bkup.enabled = 1;
 168         } else {
 169                 regmap_write(tcbpwmc->regmap,
 170                              ATMEL_TC_REG(tcbpwmc->channel, CCR),
 171                              ATMEL_TC_SWTRG);
 172                 tcbpwmc->bkup.enabled = 0;
 173         }
 174 }
 175
 176 static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
 177                                 enum pwm_polarity polarity)
 178 {
 179         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 180         struct atmel_tcb_pwm_device *tcbpwm = &tcbpwmc->pwms[pwm->hwpwm];
 181         u32 cmr;
 182
 183         /*
 184          * If duty is 0 the timer will be stopped and we have to
 185          * configure the output correctly on software trigger:
 186          *  - set output to high if PWM_POLARITY_INVERSED
 187          *  - set output to low if PWM_POLARITY_NORMAL
 188          *
 189          * This is why we're reverting polarity in this case.
 190          */
 191         if (tcbpwm->duty == 0)
 192                 polarity = !polarity;
 193
 194         regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);
 195
 196         /* flush old setting and set the new one */
 197         cmr &= ~ATMEL_TC_TCCLKS;
 198
 199         if (pwm->hwpwm == 0) {
 200                 cmr &= ~ATMEL_TC_ACMR_MASK;
 201
 202                 /* Set CMR flags according to given polarity */
 203                 if (polarity == PWM_POLARITY_INVERSED)
 204                         cmr |= ATMEL_TC_ASWTRG_CLEAR;
 205                 else
 206                         cmr |= ATMEL_TC_ASWTRG_SET;
 207         } else {
 208                 cmr &= ~ATMEL_TC_BCMR_MASK;
 209                 if (polarity == PWM_POLARITY_INVERSED)
 210                         cmr |= ATMEL_TC_BSWTRG_CLEAR;
 211                 else
 212                         cmr |= ATMEL_TC_BSWTRG_SET;
 213         }
 214
 215         /*
 216          * If duty is 0 or equal to period there's no need to register
 217          * a specific action on RA/RB and RC compare.
 218          * The output will be configured on software trigger and keep
 219          * this config till next config call.
 220          */
 221         if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) {
 222                 if (pwm->hwpwm == 0) {
 223                         if (polarity == PWM_POLARITY_INVERSED)
 224                                 cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR;
 225                         else
 226                                 cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET;
 227                 } else {
 228                         if (polarity == PWM_POLARITY_INVERSED)
 229                                 cmr |= ATMEL_TC_BCPB_SET | ATMEL_TC_BCPC_CLEAR;
 230                         else
 231                                 cmr |= ATMEL_TC_BCPB_CLEAR | ATMEL_TC_BCPC_SET;
 232                 }
 233         }
 234
 235         cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS);
 236
 237         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);
 238
 239         if (pwm->hwpwm == 0)
 240                 regmap_write(tcbpwmc->regmap,
 241                              ATMEL_TC_REG(tcbpwmc->channel, RA),
 242                              tcbpwm->duty);
 243         else
 244                 regmap_write(tcbpwmc->regmap,
 245                              ATMEL_TC_REG(tcbpwmc->channel, RB),
 246                              tcbpwm->duty);
 247
 248         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, RC),
 249                      tcbpwm->period);
 250
 251         /* Use software trigger to apply the new setting */
 252         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CCR),
 253                      ATMEL_TC_SWTRG | ATMEL_TC_CLKEN);
 254         tcbpwmc->bkup.enabled = 1;
 255         return 0;
 256 }
 257
 258 static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 259                                 int duty_ns, int period_ns)
 260 {
 261         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 262         struct atmel_tcb_pwm_device *tcbpwm = &tcbpwmc->pwms[pwm->hwpwm];
 263         /* companion PWM sharing register values period and div */
 264         struct atmel_tcb_pwm_device *atcbpwm = &tcbpwmc->pwms[pwm->hwpwm ^ 1];
 265         int i = 0;
 266         int slowclk = 0;
 267         unsigned period;
 268         unsigned duty;
 269         unsigned rate = clk_get_rate(tcbpwmc->clk);
 270         unsigned long long min;
 271         unsigned long long max;
 272
 273         /*
 274          * Find best clk divisor:
 275          * the smallest divisor which can fulfill the period_ns requirements.
 276          * If there is a gclk, the first divisor is actually the gclk selector
 277          */
 278         if (tcbpwmc->gclk)
 279                 i = 1;
 280         for (; i < ARRAY_SIZE(atmel_tcb_divisors); ++i) {
 281                 if (atmel_tcb_divisors[i] == 0) {
 282                         slowclk = i;
 283                         continue;
 284                 }
 285                 min = div_u64((u64)NSEC_PER_SEC * atmel_tcb_divisors[i], rate);
 286                 max = min << tcbpwmc->width;
 287                 if (max >= period_ns)
 288                         break;
 289         }
 290
 291         /*
 292          * If none of the divisor are small enough to represent period_ns
 293          * take slow clock (32KHz).
 294          */
 295         if (i == ARRAY_SIZE(atmel_tcb_divisors)) {
 296                 i = slowclk;
 297                 rate = clk_get_rate(tcbpwmc->slow_clk);
 298                 min = div_u64(NSEC_PER_SEC, rate);
 299                 max = min << tcbpwmc->width;
 300
 301                 /* If period is too big return ERANGE error */
 302                 if (max < period_ns)
 303                         return -ERANGE;
 304         }
 305
 306         duty = div_u64(duty_ns, min);
 307         period = div_u64(period_ns, min);
 308
 309         /*
 310          * PWM devices provided by the TCB driver are grouped by 2.
 311          * PWM devices in a given group must be configured with the
 312          * same period_ns.
 313          *
 314          * We're checking the period value of the second PWM device
 315          * in this group before applying the new config.
 316          */
 317         if ((atcbpwm->duty > 0 && atcbpwm->duty != atcbpwm->period) &&
 318                 (atcbpwm->div != i || atcbpwm->period != period)) {
 319                 dev_err(pwmchip_parent(chip),
 320                         "failed to configure period_ns: PWM group already configured with a different value\n");
 321                 return -EINVAL;
 322         }
 323
 324         tcbpwm->period = period;
 325         tcbpwm->div = i;
 326         tcbpwm->duty = duty;
 327
 328         return 0;
 329 }
 330
 331 static int atmel_tcb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 332                                const struct pwm_state *state)
 333 {
 334         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 335         int duty_cycle, period;
 336         int ret;
 337
 338         guard(spinlock)(&tcbpwmc->lock);
 339
 340         if (!state->enabled) {
 341                 atmel_tcb_pwm_disable(chip, pwm, state->polarity);
 342                 return 0;
 343         }
 344
 345         period = state->period < INT_MAX ? state->period : INT_MAX;
 346         duty_cycle = state->duty_cycle < INT_MAX ? state->duty_cycle : INT_MAX;
 347
 348         ret = atmel_tcb_pwm_config(chip, pwm, duty_cycle, period);
 349         if (ret)
 350                 return ret;
 351
 352         return atmel_tcb_pwm_enable(chip, pwm, state->polarity);
 353 }
 354
 355 static const struct pwm_ops atmel_tcb_pwm_ops = {
 356         .request = atmel_tcb_pwm_request,
 357         .free = atmel_tcb_pwm_free,
 358         .apply = atmel_tcb_pwm_apply,
 359 };
 360
 361 static struct atmel_tcb_config tcb_rm9200_config = {
 362         .counter_width = 16,
 363 };
 364
 365 static struct atmel_tcb_config tcb_sam9x5_config = {
 366         .counter_width = 32,
 367 };
 368
 369 static struct atmel_tcb_config tcb_sama5d2_config = {
 370         .counter_width = 32,
 371         .has_gclk = 1,
 372 };
 373
 374 static const struct of_device_id atmel_tcb_of_match[] = {
 375         { .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
 376         { .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
 377         { .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, },
 378         { /* sentinel */ }
 379 };
 380
 381 static int atmel_tcb_pwm_probe(struct platform_device *pdev)
 382 {
 383         struct pwm_chip *chip;
 384         const struct of_device_id *match;
 385         struct atmel_tcb_pwm_chip *tcbpwmc;
 386         const struct atmel_tcb_config *config;
 387         struct device_node *np = pdev->dev.of_node;
 388         char clk_name[] = "t0_clk";
 389         int err;
 390         int channel;
 391
 392         chip = devm_pwmchip_alloc(&pdev->dev, NPWM, sizeof(*tcbpwmc));
 393         if (IS_ERR(chip))
 394                 return PTR_ERR(chip);
 395         tcbpwmc = to_tcb_chip(chip);
 396
 397         err = of_property_read_u32(np, "reg", &channel);
 398         if (err < 0) {
 399                 dev_err(&pdev->dev,
 400                         "failed to get Timer Counter Block channel from device tree (error: %d)\n",
 401                         err);
 402                 return err;
 403         }
 404
 405         tcbpwmc->regmap = syscon_node_to_regmap(np->parent);
 406         if (IS_ERR(tcbpwmc->regmap))
 407                 return PTR_ERR(tcbpwmc->regmap);
 408
 409         tcbpwmc->slow_clk = of_clk_get_by_name(np->parent, "slow_clk");
 410         if (IS_ERR(tcbpwmc->slow_clk))
 411                 return PTR_ERR(tcbpwmc->slow_clk);
 412
 413         clk_name[1] += channel;
 414         tcbpwmc->clk = of_clk_get_by_name(np->parent, clk_name);
 415         if (IS_ERR(tcbpwmc->clk))
 416                 tcbpwmc->clk = of_clk_get_by_name(np->parent, "t0_clk");
 417         if (IS_ERR(tcbpwmc->clk)) {
 418                 err = PTR_ERR(tcbpwmc->clk);
 419                 goto err_slow_clk;
 420         }
 421
 422         match = of_match_node(atmel_tcb_of_match, np->parent);
 423         config = match->data;
 424
 425         if (config->has_gclk) {
 426                 tcbpwmc->gclk = of_clk_get_by_name(np->parent, "gclk");
 427                 if (IS_ERR(tcbpwmc->gclk)) {
 428                         err = PTR_ERR(tcbpwmc->gclk);
 429                         goto err_clk;
 430                 }
 431         }
 432
 433         chip->ops = &atmel_tcb_pwm_ops;
 434         tcbpwmc->channel = channel;
 435         tcbpwmc->width = config->counter_width;
 436
 437         err = clk_prepare_enable(tcbpwmc->slow_clk);
 438         if (err)
 439                 goto err_gclk;
 440
 441         spin_lock_init(&tcbpwmc->lock);
 442
 443         err = pwmchip_add(chip);
 444         if (err < 0)
 445                 goto err_disable_clk;
 446
 447         platform_set_drvdata(pdev, chip);
 448
 449         return 0;
 450
 451 err_disable_clk:
 452         clk_disable_unprepare(tcbpwmc->slow_clk);
 453
 454 err_gclk:
 455         clk_put(tcbpwmc->gclk);
 456
 457 err_clk:
 458         clk_put(tcbpwmc->clk);
 459
 460 err_slow_clk:
 461         clk_put(tcbpwmc->slow_clk);
 462
 463         return err;
 464 }
 465
 466 static void atmel_tcb_pwm_remove(struct platform_device *pdev)
 467 {
 468         struct pwm_chip *chip = platform_get_drvdata(pdev);
 469         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 470
 471         pwmchip_remove(chip);
 472
 473         clk_disable_unprepare(tcbpwmc->slow_clk);
 474         clk_put(tcbpwmc->gclk);
 475         clk_put(tcbpwmc->clk);
 476         clk_put(tcbpwmc->slow_clk);
 477 }
 478
 479 static const struct of_device_id atmel_tcb_pwm_dt_ids[] = {
 480         { .compatible = "atmel,tcb-pwm", },
 481         { /* sentinel */ }
 482 };
 483 MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids);
 484
 485 static int atmel_tcb_pwm_suspend(struct device *dev)
 486 {
 487         struct pwm_chip *chip = dev_get_drvdata(dev);
 488         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 489         struct atmel_tcb_channel *chan = &tcbpwmc->bkup;
 490         unsigned int channel = tcbpwmc->channel;
 491
 492         regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, CMR), &chan->cmr);
 493         regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, RA), &chan->ra);
 494         regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, RB), &chan->rb);
 495         regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, RC), &chan->rc);
 496
 497         return 0;
 498 }
 499
 500 static int atmel_tcb_pwm_resume(struct device *dev)
 501 {
 502         struct pwm_chip *chip = dev_get_drvdata(dev);
 503         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 504         struct atmel_tcb_channel *chan = &tcbpwmc->bkup;
 505         unsigned int channel = tcbpwmc->channel;
 506
 507         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, CMR), chan->cmr);
 508         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, RA), chan->ra);
 509         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, RB), chan->rb);
 510         regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, RC), chan->rc);
 511
 512         if (chan->enabled)
 513                 regmap_write(tcbpwmc->regmap,
 514                              ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
 515                              ATMEL_TC_REG(channel, CCR));
 516
 517         return 0;
 518 }
 519
 520 static DEFINE_SIMPLE_DEV_PM_OPS(atmel_tcb_pwm_pm_ops, atmel_tcb_pwm_suspend,
 521                                 atmel_tcb_pwm_resume);
 522
 523 static struct platform_driver atmel_tcb_pwm_driver = {
 524         .driver = {
 525                 .name = "atmel-tcb-pwm",
 526                 .of_match_table = atmel_tcb_pwm_dt_ids,
 527                 .pm = pm_ptr(&atmel_tcb_pwm_pm_ops),
 528         },
 529         .probe = atmel_tcb_pwm_probe,
 530         .remove = atmel_tcb_pwm_remove,
 531 };
 532 module_platform_driver(atmel_tcb_pwm_driver);
 533
 534 MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>");
 535 MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver");
 536 MODULE_LICENSE("GPL v2");