target/linux/generic/files/drivers/pwm/atmel-pwm.c

   1 /*
   2  * drivers/pwm/atmel-pwm.c
   3  *
   4  * Copyright (C) 2010 Bill Gatliff <bgat@billgatliff.com>
   5  * Copyright (C) 2007 David Brownell
   6  *
   7  * This program is free software; you may redistribute and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19  * USA
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/clk.h>
  25 #include <linux/err.h>
  26 #include <linux/io.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/slab.h>
  30 #include <linux/pwm/pwm.h>
  31
  32 enum {
  33         /* registers common to the PWMC peripheral */
  34         PWMC_MR = 0,
  35         PWMC_ENA = 4,
  36         PWMC_DIS = 8,
  37         PWMC_SR = 0xc,
  38         PWMC_IER = 0x10,
  39         PWMC_IDR = 0x14,
  40         PWMC_IMR = 0x18,
  41         PWMC_ISR = 0x1c,
  42
  43         /* registers per each PWMC channel */
  44         PWMC_CMR = 0,
  45         PWMC_CDTY = 4,
  46         PWMC_CPRD = 8,
  47         PWMC_CCNT = 0xc,
  48         PWMC_CUPD = 0x10,
  49
  50         /* how to find each channel */
  51         PWMC_CHAN_BASE = 0x200,
  52         PWMC_CHAN_STRIDE = 0x20,
  53
  54         /* CMR bits of interest */
  55         PWMC_CMR_CPD = 10,
  56         PWMC_CMR_CPOL = 9,
  57         PWMC_CMR_CALG = 8,
  58         PWMC_CMR_CPRE_MASK = 0xf,
  59 };
  60
  61 struct atmel_pwm {
  62         struct pwm_device pwm;
  63         spinlock_t lock;
  64         void __iomem *iobase;
  65         struct clk *clk;
  66         u32 *sync_mask;
  67         int irq;
  68         u32 ccnt_mask;
  69 };
  70
  71 static inline struct atmel_pwm *to_atmel_pwm(const struct pwm_channel *p)
  72 {
  73         return container_of(p->pwm, struct atmel_pwm, pwm);
  74 }
  75
  76 static inline void
  77 pwmc_writel(const struct atmel_pwm *p,
  78             unsigned offset, u32 val)
  79 {
  80         __raw_writel(val, p->iobase + offset);
  81 }
  82
  83 static inline u32
  84 pwmc_readl(const struct atmel_pwm *p,
  85            unsigned offset)
  86 {
  87         return __raw_readl(p->iobase + offset);
  88 }
  89
  90 static inline void
  91 pwmc_chan_writel(const struct pwm_channel *p,
  92                  u32 offset, u32 val)
  93 {
  94         const struct atmel_pwm *ap = to_atmel_pwm(p);
  95
  96         if (PWMC_CMR == offset)
  97                 val &= ((1 << PWMC_CMR_CPD)
  98                         | (1 << PWMC_CMR_CPOL)
  99                         | (1 << PWMC_CMR_CALG)
 100                         | (PWMC_CMR_CPRE_MASK));
 101         else
 102                 val &= ap->ccnt_mask;
 103
 104         pwmc_writel(ap, offset + PWMC_CHAN_BASE
 105                     + (p->chan * PWMC_CHAN_STRIDE), val);
 106 }
 107
 108 static inline u32
 109 pwmc_chan_readl(const struct pwm_channel *p,
 110                 u32 offset)
 111 {
 112         const struct atmel_pwm *ap = to_atmel_pwm(p);
 113
 114         return pwmc_readl(ap, offset + PWMC_CHAN_BASE
 115                           + (p->chan * PWMC_CHAN_STRIDE));
 116 }
 117
 118 static inline int
 119 __atmel_pwm_is_on(struct pwm_channel *p)
 120 {
 121         struct atmel_pwm *ap = to_atmel_pwm(p);
 122         return (pwmc_readl(ap, PWMC_SR) & (1 << p->chan)) ? 1 : 0;
 123 }
 124
 125 static inline void
 126 __atmel_pwm_unsynchronize(struct pwm_channel *p,
 127                           struct pwm_channel *to_p)
 128 {
 129         const struct atmel_pwm *ap = to_atmel_pwm(p);
 130         int wchan;
 131
 132         if (to_p) {
 133                 ap->sync_mask[p->chan] &= ~(1 << to_p->chan);
 134                 ap->sync_mask[to_p->chan] &= ~(1 << p->chan);
 135                 goto done;
 136         }
 137
 138         ap->sync_mask[p->chan] = 0;
 139         for (wchan = 0; wchan < ap->pwm.nchan; wchan++)
 140                 ap->sync_mask[wchan] &= ~(1 << p->chan);
 141 done:
 142         dev_dbg(p->pwm->dev, "sync_mask %x\n", ap->sync_mask[p->chan]);
 143 }
 144
 145 static inline void
 146 __atmel_pwm_synchronize(struct pwm_channel *p,
 147                         struct pwm_channel *to_p)
 148 {
 149         const struct atmel_pwm *ap = to_atmel_pwm(p);
 150
 151         if (!to_p)
 152                 return;
 153
 154         ap->sync_mask[p->chan] |= (1 << to_p->chan);
 155         ap->sync_mask[to_p->chan] |= (1 << p->chan);
 156
 157         dev_dbg(p->pwm->dev, "sync_mask %x\n", ap->sync_mask[p->chan]);
 158 }
 159
 160 static inline void
 161 __atmel_pwm_stop(struct pwm_channel *p)
 162 {
 163         struct atmel_pwm *ap = to_atmel_pwm(p);
 164         u32 chid = 1 << p->chan;
 165
 166         pwmc_writel(ap, PWMC_DIS, ap->sync_mask[p->chan] | chid);
 167 }
 168
 169 static inline void
 170 __atmel_pwm_start(struct pwm_channel *p)
 171 {
 172         struct atmel_pwm *ap = to_atmel_pwm(p);
 173         u32 chid = 1 << p->chan;
 174
 175         pwmc_writel(ap, PWMC_ENA, ap->sync_mask[p->chan] | chid);
 176 }
 177
 178 static int
 179 atmel_pwm_synchronize(struct pwm_channel *p,
 180                       struct pwm_channel *to_p)
 181 {
 182         unsigned long flags;
 183         spin_lock_irqsave(&p->lock, flags);
 184         __atmel_pwm_synchronize(p, to_p);
 185         spin_unlock_irqrestore(&p->lock, flags);
 186         return 0;
 187 }
 188
 189 static int
 190 atmel_pwm_unsynchronize(struct pwm_channel *p,
 191                         struct pwm_channel *from_p)
 192 {
 193         unsigned long flags;
 194         spin_lock_irqsave(&p->lock, flags);
 195         __atmel_pwm_unsynchronize(p, from_p);
 196         spin_unlock_irqrestore(&p->lock, flags);
 197         return 0;
 198 }
 199
 200 static inline int
 201 __atmel_pwm_config_polarity(struct pwm_channel *p,
 202                             struct pwm_channel_config *c)
 203 {
 204         u32 cmr = pwmc_chan_readl(p, PWMC_CMR);
 205
 206         if (c->polarity)
 207                 cmr &= ~BIT(PWMC_CMR_CPOL);
 208         else
 209                 cmr |= BIT(PWMC_CMR_CPOL);
 210         pwmc_chan_writel(p, PWMC_CMR, cmr);
 211         p->active_high = c->polarity ? 1 : 0;
 212
 213         dev_dbg(p->pwm->dev, "polarity %d\n", c->polarity);
 214         return 0;
 215 }
 216
 217 static inline int
 218 __atmel_pwm_config_duty_ticks(struct pwm_channel *p,
 219                               struct pwm_channel_config *c)
 220 {
 221         u32 cmr, cprd, cpre, cdty;
 222
 223         cmr = pwmc_chan_readl(p, PWMC_CMR);
 224         cprd = pwmc_chan_readl(p, PWMC_CPRD);
 225
 226         cpre = cmr & PWMC_CMR_CPRE_MASK;
 227         cmr &= ~BIT(PWMC_CMR_CPD);
 228
 229         cdty = cprd - (c->duty_ticks >> cpre);
 230
 231         p->duty_ticks = c->duty_ticks;
 232
 233         if (__atmel_pwm_is_on(p)) {
 234                 pwmc_chan_writel(p, PWMC_CMR, cmr);
 235                 pwmc_chan_writel(p, PWMC_CUPD, cdty);
 236         } else
 237                 pwmc_chan_writel(p, PWMC_CDTY, cdty);
 238
 239         dev_dbg(p->pwm->dev, "duty_ticks = %lu cprd = %x"
 240                 " cdty = %x cpre = %x\n", p->duty_ticks,
 241                 cprd, cdty, cpre);
 242
 243         return 0;
 244 }
 245
 246 static inline int
 247 __atmel_pwm_config_period_ticks(struct pwm_channel *p,
 248                                 struct pwm_channel_config *c)
 249 {
 250         u32 cmr, cprd, cpre;
 251
 252         cpre = fls(c->period_ticks);
 253         if (cpre < 16)
 254                 cpre = 0;
 255         else {
 256                 cpre -= 15;
 257                 if (cpre > 10)
 258                         return -EINVAL;
 259         }
 260
 261         cmr = pwmc_chan_readl(p, PWMC_CMR);
 262         cmr &= ~PWMC_CMR_CPRE_MASK;
 263         cmr |= cpre;
 264
 265         cprd = c->period_ticks >> cpre;
 266
 267         pwmc_chan_writel(p, PWMC_CMR, cmr);
 268         pwmc_chan_writel(p, PWMC_CPRD, cprd);
 269         p->period_ticks = c->period_ticks;
 270
 271         dev_dbg(p->pwm->dev, "period_ticks = %lu cprd = %x cpre = %x\n",
 272                  p->period_ticks, cprd, cpre);
 273
 274         return 0;
 275 }
 276
 277 static int
 278 atmel_pwm_config_nosleep(struct pwm_channel *p,
 279                          struct pwm_channel_config *c)
 280 {
 281         int ret = 0;
 282         unsigned long flags;
 283
 284         spin_lock_irqsave(&p->lock, flags);
 285
 286         switch (c->config_mask) {
 287
 288         case PWM_CONFIG_DUTY_TICKS:
 289                 __atmel_pwm_config_duty_ticks(p, c);
 290                 break;
 291
 292         case PWM_CONFIG_STOP:
 293                 __atmel_pwm_stop(p);
 294                 break;
 295
 296         case PWM_CONFIG_START:
 297                 __atmel_pwm_start(p);
 298                 break;
 299
 300         case PWM_CONFIG_POLARITY:
 301                 __atmel_pwm_config_polarity(p, c);
 302                 break;
 303
 304         default:
 305                 ret = -EINVAL;
 306                 break;
 307         }
 308
 309         spin_unlock_irqrestore(&p->lock, flags);
 310         return ret;
 311 }
 312
 313 static int
 314 atmel_pwm_stop_sync(struct pwm_channel *p)
 315 {
 316         struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm);
 317         int ret;
 318         int was_on = __atmel_pwm_is_on(p);
 319
 320         if (was_on) {
 321                 do {
 322                         init_completion(&p->complete);
 323                         set_bit(FLAG_STOP, &p->flags);
 324                         pwmc_writel(ap, PWMC_IER, 1 << p->chan);
 325
 326                         dev_dbg(p->pwm->dev, "waiting on stop_sync completion...\n");
 327
 328                         ret = wait_for_completion_interruptible(&p->complete);
 329
 330                         dev_dbg(p->pwm->dev, "stop_sync complete (%d)\n", ret);
 331
 332                         if (ret)
 333                                 return ret;
 334                 } while (p->flags & BIT(FLAG_STOP));
 335         }
 336
 337         return was_on;
 338 }
 339
 340 static int
 341 atmel_pwm_config(struct pwm_channel *p,
 342                  struct pwm_channel_config *c)
 343 {
 344         int was_on = 0;
 345
 346         if (p->pwm->config_nosleep) {
 347                 if (!p->pwm->config_nosleep(p, c))
 348                         return 0;
 349         }
 350
 351         might_sleep();
 352
 353         dev_dbg(p->pwm->dev, "config_mask %x\n", c->config_mask);
 354
 355         was_on = atmel_pwm_stop_sync(p);
 356         if (was_on < 0)
 357                 return was_on;
 358
 359         if (c->config_mask & PWM_CONFIG_PERIOD_TICKS) {
 360                 __atmel_pwm_config_period_ticks(p, c);
 361                 if (!(c->config_mask & PWM_CONFIG_DUTY_TICKS)) {
 362                         struct pwm_channel_config d = {
 363                                 .config_mask = PWM_CONFIG_DUTY_TICKS,
 364                                 .duty_ticks = p->duty_ticks,
 365                         };
 366                         __atmel_pwm_config_duty_ticks(p, &d);
 367                 }
 368         }
 369
 370         if (c->config_mask & PWM_CONFIG_DUTY_TICKS)
 371                 __atmel_pwm_config_duty_ticks(p, c);
 372
 373         if (c->config_mask & PWM_CONFIG_POLARITY)
 374                 __atmel_pwm_config_polarity(p, c);
 375
 376         if ((c->config_mask & PWM_CONFIG_START)
 377             || (was_on && !(c->config_mask & PWM_CONFIG_STOP)))
 378                 __atmel_pwm_start(p);
 379
 380         return 0;
 381 }
 382
 383 static void
 384 __atmel_pwm_set_callback(struct pwm_channel *p,
 385                          pwm_callback_t callback)
 386 {
 387         struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm);
 388
 389         p->callback = callback;
 390         pwmc_writel(ap, p->callback ? PWMC_IER : PWMC_IDR, 1 << p->chan);
 391 }
 392
 393 static int
 394 atmel_pwm_set_callback(struct pwm_channel *p,
 395                        pwm_callback_t callback)
 396 {
 397         struct atmel_pwm *ap = to_atmel_pwm(p);
 398         unsigned long flags;
 399
 400         spin_lock_irqsave(&ap->lock, flags);
 401         __atmel_pwm_set_callback(p, callback);
 402         spin_unlock_irqrestore(&ap->lock, flags);
 403
 404         return 0;
 405 }
 406
 407 static int
 408 atmel_pwm_request(struct pwm_channel *p)
 409 {
 410         struct atmel_pwm *ap = to_atmel_pwm(p);
 411         unsigned long flags;
 412
 413         spin_lock_irqsave(&p->lock, flags);
 414         clk_enable(ap->clk);
 415         p->tick_hz = clk_get_rate(ap->clk);
 416         __atmel_pwm_unsynchronize(p, NULL);
 417         __atmel_pwm_stop(p);
 418         spin_unlock_irqrestore(&p->lock, flags);
 419
 420         return 0;
 421 }
 422
 423 static void
 424 atmel_pwm_free(struct pwm_channel *p)
 425 {
 426         struct atmel_pwm *ap = to_atmel_pwm(p);
 427         clk_disable(ap->clk);
 428 }
 429
 430 static irqreturn_t
 431 atmel_pwmc_irq(int irq, void *data)
 432 {
 433         struct atmel_pwm *ap = data;
 434         struct pwm_channel *p;
 435         u32 isr;
 436         int chid;
 437         unsigned long flags;
 438
 439         spin_lock_irqsave(&ap->lock, flags);
 440
 441         isr = pwmc_readl(ap, PWMC_ISR);
 442         for (chid = 0; isr; chid++, isr >>= 1) {
 443                 p = &ap->pwm.channels[chid];
 444                 if (isr & 1) {
 445                         if (p->callback)
 446                                 p->callback(p);
 447                         if (p->flags & BIT(FLAG_STOP)) {
 448                                 __atmel_pwm_stop(p);
 449                                 clear_bit(FLAG_STOP, &p->flags);
 450                         }
 451                         complete_all(&p->complete);
 452                 }
 453         }
 454
 455         spin_unlock_irqrestore(&ap->lock, flags);
 456
 457         return IRQ_HANDLED;
 458 }
 459
 460 static int __devinit
 461 atmel_pwmc_probe(struct platform_device *pdev)
 462 {
 463         struct atmel_pwm *ap;
 464         struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 465         int ret = 0;
 466
 467         ap = kzalloc(sizeof(*ap), GFP_KERNEL);
 468         if (!ap) {
 469                 ret = -ENOMEM;
 470                 goto err_atmel_pwm_alloc;
 471         }
 472
 473         spin_lock_init(&ap->lock);
 474         platform_set_drvdata(pdev, ap);
 475
 476         ap->pwm.dev = &pdev->dev;
 477         ap->pwm.bus_id = dev_name(&pdev->dev);
 478
 479         ap->pwm.nchan = 4; /* TODO: true only for SAM9263 and AP7000 */
 480         ap->ccnt_mask = 0xffffUL; /* TODO: true only for SAM9263 */
 481
 482         ap->sync_mask = kzalloc(ap->pwm.nchan * sizeof(u32), GFP_KERNEL);
 483         if (!ap->sync_mask) {
 484                 ret = -ENOMEM;
 485                 goto err_alloc_sync_masks;
 486         }
 487
 488         ap->pwm.owner = THIS_MODULE;
 489         ap->pwm.request = atmel_pwm_request;
 490         ap->pwm.free = atmel_pwm_free;
 491         ap->pwm.config_nosleep = atmel_pwm_config_nosleep;
 492         ap->pwm.config = atmel_pwm_config;
 493         ap->pwm.synchronize = atmel_pwm_synchronize;
 494         ap->pwm.unsynchronize = atmel_pwm_unsynchronize;
 495         ap->pwm.set_callback = atmel_pwm_set_callback;
 496
 497         ap->clk = clk_get(&pdev->dev, "pwm_clk");
 498         if (PTR_ERR(ap->clk)) {
 499                 ret = -ENODEV;
 500                 goto err_clk_get;
 501         }
 502
 503         ap->iobase = ioremap_nocache(r->start, r->end - r->start + 1);
 504         if (!ap->iobase) {
 505                 ret = -ENODEV;
 506                 goto err_ioremap;
 507         }
 508
 509         clk_enable(ap->clk);
 510         pwmc_writel(ap, PWMC_DIS, -1);
 511         pwmc_writel(ap, PWMC_IDR, -1);
 512         clk_disable(ap->clk);
 513
 514         ap->irq = platform_get_irq(pdev, 0);
 515         if (ap->irq != -ENXIO) {
 516                 ret = request_irq(ap->irq, atmel_pwmc_irq, 0,
 517                                   ap->pwm.bus_id, ap);
 518                 if (ret)
 519                         goto err_request_irq;
 520         }
 521
 522         ret = pwm_register(&ap->pwm);
 523         if (ret)
 524                 goto err_pwm_register;
 525
 526         return 0;
 527
 528 err_pwm_register:
 529         if (ap->irq != -ENXIO)
 530                 free_irq(ap->irq, ap);
 531 err_request_irq:
 532         iounmap(ap->iobase);
 533 err_ioremap:
 534         clk_put(ap->clk);
 535 err_clk_get:
 536         platform_set_drvdata(pdev, NULL);
 537 err_alloc_sync_masks:
 538         kfree(ap);
 539 err_atmel_pwm_alloc:
 540         return ret;
 541 }
 542
 543 static int __devexit
 544 atmel_pwmc_remove(struct platform_device *pdev)
 545 {
 546         struct atmel_pwm *ap = platform_get_drvdata(pdev);
 547         int ret;
 548
 549         /* TODO: what can we do if this fails? */
 550         ret = pwm_unregister(&ap->pwm);
 551
 552         clk_enable(ap->clk);
 553         pwmc_writel(ap, PWMC_IDR, -1);
 554         pwmc_writel(ap, PWMC_DIS, -1);
 555         clk_disable(ap->clk);
 556
 557         if (ap->irq != -ENXIO)
 558                 free_irq(ap->irq, ap);
 559
 560         clk_put(ap->clk);
 561         iounmap(ap->iobase);
 562
 563         kfree(ap);
 564
 565         return 0;
 566 }
 567
 568 static struct platform_driver atmel_pwm_driver = {
 569         .driver = {
 570                 .name = "atmel_pwmc",
 571                 .owner = THIS_MODULE,
 572         },
 573         .probe = atmel_pwmc_probe,
 574         .remove = __devexit_p(atmel_pwmc_remove),
 575 };
 576
 577 static int __init atmel_pwm_init(void)
 578 {
 579         return platform_driver_register(&atmel_pwm_driver);
 580 }
 581 module_init(atmel_pwm_init);
 582
 583 static void __exit atmel_pwm_exit(void)
 584 {
 585         platform_driver_unregister(&atmel_pwm_driver);
 586 }
 587 module_exit(atmel_pwm_exit);
 588
 589 MODULE_AUTHOR("Bill Gatliff <bgat@billgatliff.com>");
 590 MODULE_DESCRIPTION("Driver for Atmel PWMC peripheral");
 591 MODULE_LICENSE("GPL");
 592 MODULE_ALIAS("platform:atmel_pwmc");