drivers/rtc/rtc-spear.c

   1 /*
   2  * drivers/rtc/rtc-spear.c
   3  *
   4  * Copyright (C) 2010 ST Microelectronics
   5  * Rajeev Kumar<rajeev-dlh.kumar@st.com>
   6  *
   7  * This file is licensed under the terms of the GNU General Public
   8  * License version 2. This program is licensed "as is" without any
   9  * warranty of any kind, whether express or implied.
  10  */
  11
  12 #include <linux/bcd.h>
  13 #include <linux/clk.h>
  14 #include <linux/delay.h>
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17 #include <linux/irq.h>
  18 #include <linux/module.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/rtc.h>
  22 #include <linux/slab.h>
  23 #include <linux/spinlock.h>
  24
  25 /* RTC registers */
  26 #define TIME_REG                0x00
  27 #define DATE_REG                0x04
  28 #define ALARM_TIME_REG          0x08
  29 #define ALARM_DATE_REG          0x0C
  30 #define CTRL_REG                0x10
  31 #define STATUS_REG              0x14
  32
  33 /* TIME_REG & ALARM_TIME_REG */
  34 #define SECONDS_UNITS           (0xf<<0)        /* seconds units position */
  35 #define SECONDS_TENS            (0x7<<4)        /* seconds tens position */
  36 #define MINUTES_UNITS           (0xf<<8)        /* minutes units position */
  37 #define MINUTES_TENS            (0x7<<12)       /* minutes tens position */
  38 #define HOURS_UNITS             (0xf<<16)       /* hours units position */
  39 #define HOURS_TENS              (0x3<<20)       /* hours tens position */
  40
  41 /* DATE_REG & ALARM_DATE_REG */
  42 #define DAYS_UNITS              (0xf<<0)        /* days units position */
  43 #define DAYS_TENS               (0x3<<4)        /* days tens position */
  44 #define MONTHS_UNITS            (0xf<<8)        /* months units position */
  45 #define MONTHS_TENS             (0x1<<12)       /* months tens position */
  46 #define YEARS_UNITS             (0xf<<16)       /* years units position */
  47 #define YEARS_TENS              (0xf<<20)       /* years tens position */
  48 #define YEARS_HUNDREDS          (0xf<<24)       /* years hundereds position */
  49 #define YEARS_MILLENIUMS        (0xf<<28)       /* years millenium position */
  50
  51 /* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
  52 #define SECOND_SHIFT            0x00            /* seconds units */
  53 #define MINUTE_SHIFT            0x08            /* minutes units position */
  54 #define HOUR_SHIFT              0x10            /* hours units position */
  55 #define MDAY_SHIFT              0x00            /* Month day shift */
  56 #define MONTH_SHIFT             0x08            /* Month shift */
  57 #define YEAR_SHIFT              0x10            /* Year shift */
  58
  59 #define SECOND_MASK             0x7F
  60 #define MIN_MASK                0x7F
  61 #define HOUR_MASK               0x3F
  62 #define DAY_MASK                0x3F
  63 #define MONTH_MASK              0x7F
  64 #define YEAR_MASK               0xFFFF
  65
  66 /* date reg equal to time reg, for debug only */
  67 #define TIME_BYP                (1<<9)
  68 #define INT_ENABLE              (1<<31)         /* interrupt enable */
  69
  70 /* STATUS_REG */
  71 #define CLK_UNCONNECTED         (1<<0)
  72 #define PEND_WR_TIME            (1<<2)
  73 #define PEND_WR_DATE            (1<<3)
  74 #define LOST_WR_TIME            (1<<4)
  75 #define LOST_WR_DATE            (1<<5)
  76 #define RTC_INT_MASK            (1<<31)
  77 #define STATUS_BUSY             (PEND_WR_TIME | PEND_WR_DATE)
  78 #define STATUS_FAIL             (LOST_WR_TIME | LOST_WR_DATE)
  79
  80 struct spear_rtc_config {
  81         struct rtc_device *rtc;
  82         struct clk *clk;
  83         spinlock_t lock;
  84         void __iomem *ioaddr;
  85         unsigned int irq_wake;
  86 };
  87
  88 static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
  89 {
  90         unsigned int val;
  91         unsigned long flags;
  92
  93         spin_lock_irqsave(&config->lock, flags);
  94         val = readl(config->ioaddr + STATUS_REG);
  95         val |= RTC_INT_MASK;
  96         writel(val, config->ioaddr + STATUS_REG);
  97         spin_unlock_irqrestore(&config->lock, flags);
  98 }
  99
 100 static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
 101 {
 102         unsigned int val;
 103
 104         val = readl(config->ioaddr + CTRL_REG);
 105         if (!(val & INT_ENABLE)) {
 106                 spear_rtc_clear_interrupt(config);
 107                 val |= INT_ENABLE;
 108                 writel(val, config->ioaddr + CTRL_REG);
 109         }
 110 }
 111
 112 static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
 113 {
 114         unsigned int val;
 115
 116         val = readl(config->ioaddr + CTRL_REG);
 117         if (val & INT_ENABLE) {
 118                 val &= ~INT_ENABLE;
 119                 writel(val, config->ioaddr + CTRL_REG);
 120         }
 121 }
 122
 123 static inline int is_write_complete(struct spear_rtc_config *config)
 124 {
 125         int ret = 0;
 126         unsigned long flags;
 127
 128         spin_lock_irqsave(&config->lock, flags);
 129         if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
 130                 ret = -EIO;
 131         spin_unlock_irqrestore(&config->lock, flags);
 132
 133         return ret;
 134 }
 135
 136 static void rtc_wait_not_busy(struct spear_rtc_config *config)
 137 {
 138         int status, count = 0;
 139         unsigned long flags;
 140
 141         /* Assuming BUSY may stay active for 80 msec) */
 142         for (count = 0; count < 80; count++) {
 143                 spin_lock_irqsave(&config->lock, flags);
 144                 status = readl(config->ioaddr + STATUS_REG);
 145                 spin_unlock_irqrestore(&config->lock, flags);
 146                 if ((status & STATUS_BUSY) == 0)
 147                         break;
 148                 /* check status busy, after each msec */
 149                 msleep(1);
 150         }
 151 }
 152
 153 static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
 154 {
 155         struct spear_rtc_config *config = dev_id;
 156         unsigned long flags, events = 0;
 157         unsigned int irq_data;
 158
 159         spin_lock_irqsave(&config->lock, flags);
 160         irq_data = readl(config->ioaddr + STATUS_REG);
 161         spin_unlock_irqrestore(&config->lock, flags);
 162
 163         if ((irq_data & RTC_INT_MASK)) {
 164                 spear_rtc_clear_interrupt(config);
 165                 events = RTC_IRQF | RTC_AF;
 166                 rtc_update_irq(config->rtc, 1, events);
 167                 return IRQ_HANDLED;
 168         } else
 169                 return IRQ_NONE;
 170
 171 }
 172
 173 static void tm2bcd(struct rtc_time *tm)
 174 {
 175         tm->tm_sec = bin2bcd(tm->tm_sec);
 176         tm->tm_min = bin2bcd(tm->tm_min);
 177         tm->tm_hour = bin2bcd(tm->tm_hour);
 178         tm->tm_mday = bin2bcd(tm->tm_mday);
 179         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 180         tm->tm_year = bin2bcd(tm->tm_year);
 181 }
 182
 183 static void bcd2tm(struct rtc_time *tm)
 184 {
 185         tm->tm_sec = bcd2bin(tm->tm_sec);
 186         tm->tm_min = bcd2bin(tm->tm_min);
 187         tm->tm_hour = bcd2bin(tm->tm_hour);
 188         tm->tm_mday = bcd2bin(tm->tm_mday);
 189         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 190         /* epoch == 1900 */
 191         tm->tm_year = bcd2bin(tm->tm_year);
 192 }
 193
 194 /*
 195  * spear_rtc_read_time - set the time
 196  * @dev: rtc device in use
 197  * @tm: holds date and time
 198  *
 199  * This function read time and date. On success it will return 0
 200  * otherwise -ve error is returned.
 201  */
 202 static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
 203 {
 204         struct spear_rtc_config *config = dev_get_drvdata(dev);
 205         unsigned int time, date;
 206
 207         /* we don't report wday/yday/isdst ... */
 208         rtc_wait_not_busy(config);
 209
 210         time = readl(config->ioaddr + TIME_REG);
 211         date = readl(config->ioaddr + DATE_REG);
 212         tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
 213         tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
 214         tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
 215         tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
 216         tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
 217         tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
 218
 219         bcd2tm(tm);
 220         return 0;
 221 }
 222
 223 /*
 224  * spear_rtc_set_time - set the time
 225  * @dev: rtc device in use
 226  * @tm: holds date and time
 227  *
 228  * This function set time and date. On success it will return 0
 229  * otherwise -ve error is returned.
 230  */
 231 static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
 232 {
 233         struct spear_rtc_config *config = dev_get_drvdata(dev);
 234         unsigned int time, date;
 235
 236         tm2bcd(tm);
 237
 238         rtc_wait_not_busy(config);
 239         time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
 240                 (tm->tm_hour << HOUR_SHIFT);
 241         date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
 242                 (tm->tm_year << YEAR_SHIFT);
 243         writel(time, config->ioaddr + TIME_REG);
 244         writel(date, config->ioaddr + DATE_REG);
 245
 246         return is_write_complete(config);
 247 }
 248
 249 /*
 250  * spear_rtc_read_alarm - read the alarm time
 251  * @dev: rtc device in use
 252  * @alm: holds alarm date and time
 253  *
 254  * This function read alarm time and date. On success it will return 0
 255  * otherwise -ve error is returned.
 256  */
 257 static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 258 {
 259         struct spear_rtc_config *config = dev_get_drvdata(dev);
 260         unsigned int time, date;
 261
 262         rtc_wait_not_busy(config);
 263
 264         time = readl(config->ioaddr + ALARM_TIME_REG);
 265         date = readl(config->ioaddr + ALARM_DATE_REG);
 266         alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
 267         alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
 268         alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
 269         alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
 270         alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
 271         alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
 272
 273         bcd2tm(&alm->time);
 274         alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
 275
 276         return 0;
 277 }
 278
 279 /*
 280  * spear_rtc_set_alarm - set the alarm time
 281  * @dev: rtc device in use
 282  * @alm: holds alarm date and time
 283  *
 284  * This function set alarm time and date. On success it will return 0
 285  * otherwise -ve error is returned.
 286  */
 287 static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 288 {
 289         struct spear_rtc_config *config = dev_get_drvdata(dev);
 290         unsigned int time, date;
 291         int err;
 292
 293         tm2bcd(&alm->time);
 294
 295         rtc_wait_not_busy(config);
 296
 297         time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
 298                         MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);
 299         date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
 300                         MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
 301
 302         writel(time, config->ioaddr + ALARM_TIME_REG);
 303         writel(date, config->ioaddr + ALARM_DATE_REG);
 304         err = is_write_complete(config);
 305         if (err < 0)
 306                 return err;
 307
 308         if (alm->enabled)
 309                 spear_rtc_enable_interrupt(config);
 310         else
 311                 spear_rtc_disable_interrupt(config);
 312
 313         return 0;
 314 }
 315
 316 static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
 317 {
 318         struct spear_rtc_config *config = dev_get_drvdata(dev);
 319         int ret = 0;
 320
 321         spear_rtc_clear_interrupt(config);
 322
 323         switch (enabled) {
 324         case 0:
 325                 /* alarm off */
 326                 spear_rtc_disable_interrupt(config);
 327                 break;
 328         case 1:
 329                 /* alarm on */
 330                 spear_rtc_enable_interrupt(config);
 331                 break;
 332         default:
 333                 ret = -EINVAL;
 334                 break;
 335         }
 336
 337         return ret;
 338 }
 339
 340 static const struct rtc_class_ops spear_rtc_ops = {
 341         .read_time = spear_rtc_read_time,
 342         .set_time = spear_rtc_set_time,
 343         .read_alarm = spear_rtc_read_alarm,
 344         .set_alarm = spear_rtc_set_alarm,
 345         .alarm_irq_enable = spear_alarm_irq_enable,
 346 };
 347
 348 static int spear_rtc_probe(struct platform_device *pdev)
 349 {
 350         struct resource *res;
 351         struct spear_rtc_config *config;
 352         int status = 0;
 353         int irq;
 354
 355         config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
 356         if (!config)
 357                 return -ENOMEM;
 358
 359         /* alarm irqs */
 360         irq = platform_get_irq(pdev, 0);
 361         if (irq < 0) {
 362                 dev_err(&pdev->dev, "no update irq?\n");
 363                 return irq;
 364         }
 365
 366         status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
 367                         config);
 368         if (status) {
 369                 dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
 370                                 irq);
 371                 return status;
 372         }
 373
 374         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 375         config->ioaddr = devm_ioremap_resource(&pdev->dev, res);
 376         if (IS_ERR(config->ioaddr))
 377                 return PTR_ERR(config->ioaddr);
 378
 379         config->clk = devm_clk_get(&pdev->dev, NULL);
 380         if (IS_ERR(config->clk))
 381                 return PTR_ERR(config->clk);
 382
 383         status = clk_prepare_enable(config->clk);
 384         if (status < 0)
 385                 return status;
 386
 387         spin_lock_init(&config->lock);
 388         platform_set_drvdata(pdev, config);
 389
 390         config->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 391                                         &spear_rtc_ops, THIS_MODULE);
 392         if (IS_ERR(config->rtc)) {
 393                 dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
 394                                 PTR_ERR(config->rtc));
 395                 status = PTR_ERR(config->rtc);
 396                 goto err_disable_clock;
 397         }
 398
 399         config->rtc->uie_unsupported = 1;
 400
 401         if (!device_can_wakeup(&pdev->dev))
 402                 device_init_wakeup(&pdev->dev, 1);
 403
 404         return 0;
 405
 406 err_disable_clock:
 407         clk_disable_unprepare(config->clk);
 408
 409         return status;
 410 }
 411
 412 static int spear_rtc_remove(struct platform_device *pdev)
 413 {
 414         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 415
 416         spear_rtc_disable_interrupt(config);
 417         clk_disable_unprepare(config->clk);
 418         device_init_wakeup(&pdev->dev, 0);
 419
 420         return 0;
 421 }
 422
 423 #ifdef CONFIG_PM_SLEEP
 424 static int spear_rtc_suspend(struct device *dev)
 425 {
 426         struct platform_device *pdev = to_platform_device(dev);
 427         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 428         int irq;
 429
 430         irq = platform_get_irq(pdev, 0);
 431         if (device_may_wakeup(&pdev->dev)) {
 432                 if (!enable_irq_wake(irq))
 433                         config->irq_wake = 1;
 434         } else {
 435                 spear_rtc_disable_interrupt(config);
 436                 clk_disable(config->clk);
 437         }
 438
 439         return 0;
 440 }
 441
 442 static int spear_rtc_resume(struct device *dev)
 443 {
 444         struct platform_device *pdev = to_platform_device(dev);
 445         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 446         int irq;
 447
 448         irq = platform_get_irq(pdev, 0);
 449
 450         if (device_may_wakeup(&pdev->dev)) {
 451                 if (config->irq_wake) {
 452                         disable_irq_wake(irq);
 453                         config->irq_wake = 0;
 454                 }
 455         } else {
 456                 clk_enable(config->clk);
 457                 spear_rtc_enable_interrupt(config);
 458         }
 459
 460         return 0;
 461 }
 462 #endif
 463
 464 static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
 465
 466 static void spear_rtc_shutdown(struct platform_device *pdev)
 467 {
 468         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 469
 470         spear_rtc_disable_interrupt(config);
 471         clk_disable(config->clk);
 472 }
 473
 474 #ifdef CONFIG_OF
 475 static const struct of_device_id spear_rtc_id_table[] = {
 476         { .compatible = "st,spear600-rtc" },
 477         {}
 478 };
 479 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
 480 #endif
 481
 482 static struct platform_driver spear_rtc_driver = {
 483         .probe = spear_rtc_probe,
 484         .remove = spear_rtc_remove,
 485         .shutdown = spear_rtc_shutdown,
 486         .driver = {
 487                 .name = "rtc-spear",
 488                 .pm = &spear_rtc_pm_ops,
 489                 .of_match_table = of_match_ptr(spear_rtc_id_table),
 490         },
 491 };
 492
 493 module_platform_driver(spear_rtc_driver);
 494
 495 MODULE_ALIAS("platform:rtc-spear");
 496 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
 497 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
 498 MODULE_LICENSE("GPL");