drivers/clocksource/sh_mtu2.c

   1 /*
   2  * SuperH Timer Support - MTU2
   3  *
   4  *  Copyright (C) 2009 Magnus Damm
   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
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/clk.h>
  17 #include <linux/clockchips.h>
  18 #include <linux/delay.h>
  19 #include <linux/err.h>
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/io.h>
  23 #include <linux/ioport.h>
  24 #include <linux/irq.h>
  25 #include <linux/module.h>
  26 #include <linux/of.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/pm_domain.h>
  29 #include <linux/pm_runtime.h>
  30 #include <linux/sh_timer.h>
  31 #include <linux/slab.h>
  32 #include <linux/spinlock.h>
  33
  34 struct sh_mtu2_device;
  35
  36 struct sh_mtu2_channel {
  37         struct sh_mtu2_device *mtu;
  38         unsigned int index;
  39
  40         void __iomem *base;
  41
  42         struct clock_event_device ced;
  43 };
  44
  45 struct sh_mtu2_device {
  46         struct platform_device *pdev;
  47
  48         void __iomem *mapbase;
  49         struct clk *clk;
  50
  51         raw_spinlock_t lock; /* Protect the shared registers */
  52
  53         struct sh_mtu2_channel *channels;
  54         unsigned int num_channels;
  55
  56         bool has_clockevent;
  57 };
  58
  59 #define TSTR -1 /* shared register */
  60 #define TCR  0 /* channel register */
  61 #define TMDR 1 /* channel register */
  62 #define TIOR 2 /* channel register */
  63 #define TIER 3 /* channel register */
  64 #define TSR  4 /* channel register */
  65 #define TCNT 5 /* channel register */
  66 #define TGR  6 /* channel register */
  67
  68 #define TCR_CCLR_NONE           (0 << 5)
  69 #define TCR_CCLR_TGRA           (1 << 5)
  70 #define TCR_CCLR_TGRB           (2 << 5)
  71 #define TCR_CCLR_SYNC           (3 << 5)
  72 #define TCR_CCLR_TGRC           (5 << 5)
  73 #define TCR_CCLR_TGRD           (6 << 5)
  74 #define TCR_CCLR_MASK           (7 << 5)
  75 #define TCR_CKEG_RISING         (0 << 3)
  76 #define TCR_CKEG_FALLING        (1 << 3)
  77 #define TCR_CKEG_BOTH           (2 << 3)
  78 #define TCR_CKEG_MASK           (3 << 3)
  79 /* Values 4 to 7 are channel-dependent */
  80 #define TCR_TPSC_P1             (0 << 0)
  81 #define TCR_TPSC_P4             (1 << 0)
  82 #define TCR_TPSC_P16            (2 << 0)
  83 #define TCR_TPSC_P64            (3 << 0)
  84 #define TCR_TPSC_CH0_TCLKA      (4 << 0)
  85 #define TCR_TPSC_CH0_TCLKB      (5 << 0)
  86 #define TCR_TPSC_CH0_TCLKC      (6 << 0)
  87 #define TCR_TPSC_CH0_TCLKD      (7 << 0)
  88 #define TCR_TPSC_CH1_TCLKA      (4 << 0)
  89 #define TCR_TPSC_CH1_TCLKB      (5 << 0)
  90 #define TCR_TPSC_CH1_P256       (6 << 0)
  91 #define TCR_TPSC_CH1_TCNT2      (7 << 0)
  92 #define TCR_TPSC_CH2_TCLKA      (4 << 0)
  93 #define TCR_TPSC_CH2_TCLKB      (5 << 0)
  94 #define TCR_TPSC_CH2_TCLKC      (6 << 0)
  95 #define TCR_TPSC_CH2_P1024      (7 << 0)
  96 #define TCR_TPSC_CH34_P256      (4 << 0)
  97 #define TCR_TPSC_CH34_P1024     (5 << 0)
  98 #define TCR_TPSC_CH34_TCLKA     (6 << 0)
  99 #define TCR_TPSC_CH34_TCLKB     (7 << 0)
 100 #define TCR_TPSC_MASK           (7 << 0)
 101
 102 #define TMDR_BFE                (1 << 6)
 103 #define TMDR_BFB                (1 << 5)
 104 #define TMDR_BFA                (1 << 4)
 105 #define TMDR_MD_NORMAL          (0 << 0)
 106 #define TMDR_MD_PWM_1           (2 << 0)
 107 #define TMDR_MD_PWM_2           (3 << 0)
 108 #define TMDR_MD_PHASE_1         (4 << 0)
 109 #define TMDR_MD_PHASE_2         (5 << 0)
 110 #define TMDR_MD_PHASE_3         (6 << 0)
 111 #define TMDR_MD_PHASE_4         (7 << 0)
 112 #define TMDR_MD_PWM_SYNC        (8 << 0)
 113 #define TMDR_MD_PWM_COMP_CREST  (13 << 0)
 114 #define TMDR_MD_PWM_COMP_TROUGH (14 << 0)
 115 #define TMDR_MD_PWM_COMP_BOTH   (15 << 0)
 116 #define TMDR_MD_MASK            (15 << 0)
 117
 118 #define TIOC_IOCH(n)            ((n) << 4)
 119 #define TIOC_IOCL(n)            ((n) << 0)
 120 #define TIOR_OC_RETAIN          (0 << 0)
 121 #define TIOR_OC_0_CLEAR         (1 << 0)
 122 #define TIOR_OC_0_SET           (2 << 0)
 123 #define TIOR_OC_0_TOGGLE        (3 << 0)
 124 #define TIOR_OC_1_CLEAR         (5 << 0)
 125 #define TIOR_OC_1_SET           (6 << 0)
 126 #define TIOR_OC_1_TOGGLE        (7 << 0)
 127 #define TIOR_IC_RISING          (8 << 0)
 128 #define TIOR_IC_FALLING         (9 << 0)
 129 #define TIOR_IC_BOTH            (10 << 0)
 130 #define TIOR_IC_TCNT            (12 << 0)
 131 #define TIOR_MASK               (15 << 0)
 132
 133 #define TIER_TTGE               (1 << 7)
 134 #define TIER_TTGE2              (1 << 6)
 135 #define TIER_TCIEU              (1 << 5)
 136 #define TIER_TCIEV              (1 << 4)
 137 #define TIER_TGIED              (1 << 3)
 138 #define TIER_TGIEC              (1 << 2)
 139 #define TIER_TGIEB              (1 << 1)
 140 #define TIER_TGIEA              (1 << 0)
 141
 142 #define TSR_TCFD                (1 << 7)
 143 #define TSR_TCFU                (1 << 5)
 144 #define TSR_TCFV                (1 << 4)
 145 #define TSR_TGFD                (1 << 3)
 146 #define TSR_TGFC                (1 << 2)
 147 #define TSR_TGFB                (1 << 1)
 148 #define TSR_TGFA                (1 << 0)
 149
 150 static unsigned long mtu2_reg_offs[] = {
 151         [TCR] = 0,
 152         [TMDR] = 1,
 153         [TIOR] = 2,
 154         [TIER] = 4,
 155         [TSR] = 5,
 156         [TCNT] = 6,
 157         [TGR] = 8,
 158 };
 159
 160 static inline unsigned long sh_mtu2_read(struct sh_mtu2_channel *ch, int reg_nr)
 161 {
 162         unsigned long offs;
 163
 164         if (reg_nr == TSTR)
 165                 return ioread8(ch->mtu->mapbase + 0x280);
 166
 167         offs = mtu2_reg_offs[reg_nr];
 168
 169         if ((reg_nr == TCNT) || (reg_nr == TGR))
 170                 return ioread16(ch->base + offs);
 171         else
 172                 return ioread8(ch->base + offs);
 173 }
 174
 175 static inline void sh_mtu2_write(struct sh_mtu2_channel *ch, int reg_nr,
 176                                 unsigned long value)
 177 {
 178         unsigned long offs;
 179
 180         if (reg_nr == TSTR)
 181                 return iowrite8(value, ch->mtu->mapbase + 0x280);
 182
 183         offs = mtu2_reg_offs[reg_nr];
 184
 185         if ((reg_nr == TCNT) || (reg_nr == TGR))
 186                 iowrite16(value, ch->base + offs);
 187         else
 188                 iowrite8(value, ch->base + offs);
 189 }
 190
 191 static void sh_mtu2_start_stop_ch(struct sh_mtu2_channel *ch, int start)
 192 {
 193         unsigned long flags, value;
 194
 195         /* start stop register shared by multiple timer channels */
 196         raw_spin_lock_irqsave(&ch->mtu->lock, flags);
 197         value = sh_mtu2_read(ch, TSTR);
 198
 199         if (start)
 200                 value |= 1 << ch->index;
 201         else
 202                 value &= ~(1 << ch->index);
 203
 204         sh_mtu2_write(ch, TSTR, value);
 205         raw_spin_unlock_irqrestore(&ch->mtu->lock, flags);
 206 }
 207
 208 static int sh_mtu2_enable(struct sh_mtu2_channel *ch)
 209 {
 210         unsigned long periodic;
 211         unsigned long rate;
 212         int ret;
 213
 214         pm_runtime_get_sync(&ch->mtu->pdev->dev);
 215         dev_pm_syscore_device(&ch->mtu->pdev->dev, true);
 216
 217         /* enable clock */
 218         ret = clk_enable(ch->mtu->clk);
 219         if (ret) {
 220                 dev_err(&ch->mtu->pdev->dev, "ch%u: cannot enable clock\n",
 221                         ch->index);
 222                 return ret;
 223         }
 224
 225         /* make sure channel is disabled */
 226         sh_mtu2_start_stop_ch(ch, 0);
 227
 228         rate = clk_get_rate(ch->mtu->clk) / 64;
 229         periodic = (rate + HZ/2) / HZ;
 230
 231         /*
 232          * "Periodic Counter Operation"
 233          * Clear on TGRA compare match, divide clock by 64.
 234          */
 235         sh_mtu2_write(ch, TCR, TCR_CCLR_TGRA | TCR_TPSC_P64);
 236         sh_mtu2_write(ch, TIOR, TIOC_IOCH(TIOR_OC_0_CLEAR) |
 237                       TIOC_IOCL(TIOR_OC_0_CLEAR));
 238         sh_mtu2_write(ch, TGR, periodic);
 239         sh_mtu2_write(ch, TCNT, 0);
 240         sh_mtu2_write(ch, TMDR, TMDR_MD_NORMAL);
 241         sh_mtu2_write(ch, TIER, TIER_TGIEA);
 242
 243         /* enable channel */
 244         sh_mtu2_start_stop_ch(ch, 1);
 245
 246         return 0;
 247 }
 248
 249 static void sh_mtu2_disable(struct sh_mtu2_channel *ch)
 250 {
 251         /* disable channel */
 252         sh_mtu2_start_stop_ch(ch, 0);
 253
 254         /* stop clock */
 255         clk_disable(ch->mtu->clk);
 256
 257         dev_pm_syscore_device(&ch->mtu->pdev->dev, false);
 258         pm_runtime_put(&ch->mtu->pdev->dev);
 259 }
 260
 261 static irqreturn_t sh_mtu2_interrupt(int irq, void *dev_id)
 262 {
 263         struct sh_mtu2_channel *ch = dev_id;
 264
 265         /* acknowledge interrupt */
 266         sh_mtu2_read(ch, TSR);
 267         sh_mtu2_write(ch, TSR, ~TSR_TGFA);
 268
 269         /* notify clockevent layer */
 270         ch->ced.event_handler(&ch->ced);
 271         return IRQ_HANDLED;
 272 }
 273
 274 static struct sh_mtu2_channel *ced_to_sh_mtu2(struct clock_event_device *ced)
 275 {
 276         return container_of(ced, struct sh_mtu2_channel, ced);
 277 }
 278
 279 static int sh_mtu2_clock_event_shutdown(struct clock_event_device *ced)
 280 {
 281         struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);
 282
 283         if (clockevent_state_periodic(ced))
 284                 sh_mtu2_disable(ch);
 285
 286         return 0;
 287 }
 288
 289 static int sh_mtu2_clock_event_set_periodic(struct clock_event_device *ced)
 290 {
 291         struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);
 292
 293         if (clockevent_state_periodic(ced))
 294                 sh_mtu2_disable(ch);
 295
 296         dev_info(&ch->mtu->pdev->dev, "ch%u: used for periodic clock events\n",
 297                  ch->index);
 298         sh_mtu2_enable(ch);
 299         return 0;
 300 }
 301
 302 static void sh_mtu2_clock_event_suspend(struct clock_event_device *ced)
 303 {
 304         pm_genpd_syscore_poweroff(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
 305 }
 306
 307 static void sh_mtu2_clock_event_resume(struct clock_event_device *ced)
 308 {
 309         pm_genpd_syscore_poweron(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
 310 }
 311
 312 static void sh_mtu2_register_clockevent(struct sh_mtu2_channel *ch,
 313                                         const char *name)
 314 {
 315         struct clock_event_device *ced = &ch->ced;
 316
 317         ced->name = name;
 318         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 319         ced->rating = 200;
 320         ced->cpumask = cpu_possible_mask;
 321         ced->set_state_shutdown = sh_mtu2_clock_event_shutdown;
 322         ced->set_state_periodic = sh_mtu2_clock_event_set_periodic;
 323         ced->suspend = sh_mtu2_clock_event_suspend;
 324         ced->resume = sh_mtu2_clock_event_resume;
 325
 326         dev_info(&ch->mtu->pdev->dev, "ch%u: used for clock events\n",
 327                  ch->index);
 328         clockevents_register_device(ced);
 329 }
 330
 331 static int sh_mtu2_register(struct sh_mtu2_channel *ch, const char *name)
 332 {
 333         ch->mtu->has_clockevent = true;
 334         sh_mtu2_register_clockevent(ch, name);
 335
 336         return 0;
 337 }
 338
 339 static int sh_mtu2_setup_channel(struct sh_mtu2_channel *ch, unsigned int index,
 340                                  struct sh_mtu2_device *mtu)
 341 {
 342         static const unsigned int channel_offsets[] = {
 343                 0x300, 0x380, 0x000,
 344         };
 345         char name[6];
 346         int irq;
 347         int ret;
 348
 349         ch->mtu = mtu;
 350
 351         sprintf(name, "tgi%ua", index);
 352         irq = platform_get_irq_byname(mtu->pdev, name);
 353         if (irq < 0) {
 354                 /* Skip channels with no declared interrupt. */
 355                 return 0;
 356         }
 357
 358         ret = request_irq(irq, sh_mtu2_interrupt,
 359                           IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
 360                           dev_name(&ch->mtu->pdev->dev), ch);
 361         if (ret) {
 362                 dev_err(&ch->mtu->pdev->dev, "ch%u: failed to request irq %d\n",
 363                         index, irq);
 364                 return ret;
 365         }
 366
 367         ch->base = mtu->mapbase + channel_offsets[index];
 368         ch->index = index;
 369
 370         return sh_mtu2_register(ch, dev_name(&mtu->pdev->dev));
 371 }
 372
 373 static int sh_mtu2_map_memory(struct sh_mtu2_device *mtu)
 374 {
 375         struct resource *res;
 376
 377         res = platform_get_resource(mtu->pdev, IORESOURCE_MEM, 0);
 378         if (!res) {
 379                 dev_err(&mtu->pdev->dev, "failed to get I/O memory\n");
 380                 return -ENXIO;
 381         }
 382
 383         mtu->mapbase = ioremap_nocache(res->start, resource_size(res));
 384         if (mtu->mapbase == NULL)
 385                 return -ENXIO;
 386
 387         return 0;
 388 }
 389
 390 static int sh_mtu2_setup(struct sh_mtu2_device *mtu,
 391                          struct platform_device *pdev)
 392 {
 393         unsigned int i;
 394         int ret;
 395
 396         mtu->pdev = pdev;
 397
 398         raw_spin_lock_init(&mtu->lock);
 399
 400         /* Get hold of clock. */
 401         mtu->clk = clk_get(&mtu->pdev->dev, "fck");
 402         if (IS_ERR(mtu->clk)) {
 403                 dev_err(&mtu->pdev->dev, "cannot get clock\n");
 404                 return PTR_ERR(mtu->clk);
 405         }
 406
 407         ret = clk_prepare(mtu->clk);
 408         if (ret < 0)
 409                 goto err_clk_put;
 410
 411         /* Map the memory resource. */
 412         ret = sh_mtu2_map_memory(mtu);
 413         if (ret < 0) {
 414                 dev_err(&mtu->pdev->dev, "failed to remap I/O memory\n");
 415                 goto err_clk_unprepare;
 416         }
 417
 418         /* Allocate and setup the channels. */
 419         mtu->num_channels = 3;
 420
 421         mtu->channels = kcalloc(mtu->num_channels, sizeof(*mtu->channels),
 422                                 GFP_KERNEL);
 423         if (mtu->channels == NULL) {
 424                 ret = -ENOMEM;
 425                 goto err_unmap;
 426         }
 427
 428         for (i = 0; i < mtu->num_channels; ++i) {
 429                 ret = sh_mtu2_setup_channel(&mtu->channels[i], i, mtu);
 430                 if (ret < 0)
 431                         goto err_unmap;
 432         }
 433
 434         platform_set_drvdata(pdev, mtu);
 435
 436         return 0;
 437
 438 err_unmap:
 439         kfree(mtu->channels);
 440         iounmap(mtu->mapbase);
 441 err_clk_unprepare:
 442         clk_unprepare(mtu->clk);
 443 err_clk_put:
 444         clk_put(mtu->clk);
 445         return ret;
 446 }
 447
 448 static int sh_mtu2_probe(struct platform_device *pdev)
 449 {
 450         struct sh_mtu2_device *mtu = platform_get_drvdata(pdev);
 451         int ret;
 452
 453         if (!is_early_platform_device(pdev)) {
 454                 pm_runtime_set_active(&pdev->dev);
 455                 pm_runtime_enable(&pdev->dev);
 456         }
 457
 458         if (mtu) {
 459                 dev_info(&pdev->dev, "kept as earlytimer\n");
 460                 goto out;
 461         }
 462
 463         mtu = kzalloc(sizeof(*mtu), GFP_KERNEL);
 464         if (mtu == NULL)
 465                 return -ENOMEM;
 466
 467         ret = sh_mtu2_setup(mtu, pdev);
 468         if (ret) {
 469                 kfree(mtu);
 470                 pm_runtime_idle(&pdev->dev);
 471                 return ret;
 472         }
 473         if (is_early_platform_device(pdev))
 474                 return 0;
 475
 476  out:
 477         if (mtu->has_clockevent)
 478                 pm_runtime_irq_safe(&pdev->dev);
 479         else
 480                 pm_runtime_idle(&pdev->dev);
 481
 482         return 0;
 483 }
 484
 485 static int sh_mtu2_remove(struct platform_device *pdev)
 486 {
 487         return -EBUSY; /* cannot unregister clockevent */
 488 }
 489
 490 static const struct platform_device_id sh_mtu2_id_table[] = {
 491         { "sh-mtu2", 0 },
 492         { },
 493 };
 494 MODULE_DEVICE_TABLE(platform, sh_mtu2_id_table);
 495
 496 static const struct of_device_id sh_mtu2_of_table[] __maybe_unused = {
 497         { .compatible = "renesas,mtu2" },
 498         { }
 499 };
 500 MODULE_DEVICE_TABLE(of, sh_mtu2_of_table);
 501
 502 static struct platform_driver sh_mtu2_device_driver = {
 503         .probe          = sh_mtu2_probe,
 504         .remove         = sh_mtu2_remove,
 505         .driver         = {
 506                 .name   = "sh_mtu2",
 507                 .of_match_table = of_match_ptr(sh_mtu2_of_table),
 508         },
 509         .id_table       = sh_mtu2_id_table,
 510 };
 511
 512 static int __init sh_mtu2_init(void)
 513 {
 514         return platform_driver_register(&sh_mtu2_device_driver);
 515 }
 516
 517 static void __exit sh_mtu2_exit(void)
 518 {
 519         platform_driver_unregister(&sh_mtu2_device_driver);
 520 }
 521
 522 early_platform_init("earlytimer", &sh_mtu2_device_driver);
 523 subsys_initcall(sh_mtu2_init);
 524 module_exit(sh_mtu2_exit);
 525
 526 MODULE_AUTHOR("Magnus Damm");
 527 MODULE_DESCRIPTION("SuperH MTU2 Timer Driver");
 528 MODULE_LICENSE("GPL v2");