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 int tm2bcd(struct rtc_time *tm)
 174 {
 175         if (rtc_valid_tm(tm) != 0)
 176                 return -EINVAL;
 177         tm->tm_sec = bin2bcd(tm->tm_sec);
 178         tm->tm_min = bin2bcd(tm->tm_min);
 179         tm->tm_hour = bin2bcd(tm->tm_hour);
 180         tm->tm_mday = bin2bcd(tm->tm_mday);
 181         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 182         tm->tm_year = bin2bcd(tm->tm_year);
 183
 184         return 0;
 185 }
 186
 187 static void bcd2tm(struct rtc_time *tm)
 188 {
 189         tm->tm_sec = bcd2bin(tm->tm_sec);
 190         tm->tm_min = bcd2bin(tm->tm_min);
 191         tm->tm_hour = bcd2bin(tm->tm_hour);
 192         tm->tm_mday = bcd2bin(tm->tm_mday);
 193         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 194         /* epoch == 1900 */
 195         tm->tm_year = bcd2bin(tm->tm_year);
 196 }
 197
 198 /*
 199  * spear_rtc_read_time - set the time
 200  * @dev: rtc device in use
 201  * @tm: holds date and time
 202  *
 203  * This function read time and date. On success it will return 0
 204  * otherwise -ve error is returned.
 205  */
 206 static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
 207 {
 208         struct spear_rtc_config *config = dev_get_drvdata(dev);
 209         unsigned int time, date;
 210
 211         /* we don't report wday/yday/isdst ... */
 212         rtc_wait_not_busy(config);
 213
 214         time = readl(config->ioaddr + TIME_REG);
 215         date = readl(config->ioaddr + DATE_REG);
 216         tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
 217         tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
 218         tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
 219         tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
 220         tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
 221         tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
 222
 223         bcd2tm(tm);
 224         return 0;
 225 }
 226
 227 /*
 228  * spear_rtc_set_time - set the time
 229  * @dev: rtc device in use
 230  * @tm: holds date and time
 231  *
 232  * This function set time and date. On success it will return 0
 233  * otherwise -ve error is returned.
 234  */
 235 static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
 236 {
 237         struct spear_rtc_config *config = dev_get_drvdata(dev);
 238         unsigned int time, date;
 239
 240         if (tm2bcd(tm) < 0)
 241                 return -EINVAL;
 242
 243         rtc_wait_not_busy(config);
 244         time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
 245                 (tm->tm_hour << HOUR_SHIFT);
 246         date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
 247                 (tm->tm_year << YEAR_SHIFT);
 248         writel(time, config->ioaddr + TIME_REG);
 249         writel(date, config->ioaddr + DATE_REG);
 250
 251         return is_write_complete(config);
 252 }
 253
 254 /*
 255  * spear_rtc_read_alarm - read the alarm time
 256  * @dev: rtc device in use
 257  * @alm: holds alarm date and time
 258  *
 259  * This function read alarm time and date. On success it will return 0
 260  * otherwise -ve error is returned.
 261  */
 262 static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 263 {
 264         struct spear_rtc_config *config = dev_get_drvdata(dev);
 265         unsigned int time, date;
 266
 267         rtc_wait_not_busy(config);
 268
 269         time = readl(config->ioaddr + ALARM_TIME_REG);
 270         date = readl(config->ioaddr + ALARM_DATE_REG);
 271         alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
 272         alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
 273         alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
 274         alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
 275         alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
 276         alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
 277
 278         bcd2tm(&alm->time);
 279         alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
 280
 281         return 0;
 282 }
 283
 284 /*
 285  * spear_rtc_set_alarm - set the alarm time
 286  * @dev: rtc device in use
 287  * @alm: holds alarm date and time
 288  *
 289  * This function set alarm time and date. On success it will return 0
 290  * otherwise -ve error is returned.
 291  */
 292 static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 293 {
 294         struct spear_rtc_config *config = dev_get_drvdata(dev);
 295         unsigned int time, date;
 296         int err;
 297
 298         if (tm2bcd(&alm->time) < 0)
 299                 return -EINVAL;
 300
 301         rtc_wait_not_busy(config);
 302
 303         time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
 304                         MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);
 305         date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
 306                         MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
 307
 308         writel(time, config->ioaddr + ALARM_TIME_REG);
 309         writel(date, config->ioaddr + ALARM_DATE_REG);
 310         err = is_write_complete(config);
 311         if (err < 0)
 312                 return err;
 313
 314         if (alm->enabled)
 315                 spear_rtc_enable_interrupt(config);
 316         else
 317                 spear_rtc_disable_interrupt(config);
 318
 319         return 0;
 320 }
 321
 322 static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
 323 {
 324         struct spear_rtc_config *config = dev_get_drvdata(dev);
 325         int ret = 0;
 326
 327         spear_rtc_clear_interrupt(config);
 328
 329         switch (enabled) {
 330         case 0:
 331                 /* alarm off */
 332                 spear_rtc_disable_interrupt(config);
 333                 break;
 334         case 1:
 335                 /* alarm on */
 336                 spear_rtc_enable_interrupt(config);
 337                 break;
 338         default:
 339                 ret = -EINVAL;
 340                 break;
 341         }
 342
 343         return ret;
 344 }
 345
 346 static struct rtc_class_ops spear_rtc_ops = {
 347         .read_time = spear_rtc_read_time,
 348         .set_time = spear_rtc_set_time,
 349         .read_alarm = spear_rtc_read_alarm,
 350         .set_alarm = spear_rtc_set_alarm,
 351         .alarm_irq_enable = spear_alarm_irq_enable,
 352 };
 353
 354 static int spear_rtc_probe(struct platform_device *pdev)
 355 {
 356         struct resource *res;
 357         struct spear_rtc_config *config;
 358         int status = 0;
 359         int irq;
 360
 361         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 362         if (!res) {
 363                 dev_err(&pdev->dev, "no resource defined\n");
 364                 return -EBUSY;
 365         }
 366
 367         config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
 368         if (!config) {
 369                 dev_err(&pdev->dev, "out of memory\n");
 370                 return -ENOMEM;
 371         }
 372
 373         /* alarm irqs */
 374         irq = platform_get_irq(pdev, 0);
 375         if (irq < 0) {
 376                 dev_err(&pdev->dev, "no update irq?\n");
 377                 return irq;
 378         }
 379
 380         status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
 381                         config);
 382         if (status) {
 383                 dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
 384                                 irq);
 385                 return status;
 386         }
 387
 388         config->ioaddr = devm_request_and_ioremap(&pdev->dev, res);
 389         if (!config->ioaddr) {
 390                 dev_err(&pdev->dev, "request-ioremap fail\n");
 391                 return -ENOMEM;
 392         }
 393
 394         config->clk = devm_clk_get(&pdev->dev, NULL);
 395         if (IS_ERR(config->clk))
 396                 return PTR_ERR(config->clk);
 397
 398         status = clk_prepare_enable(config->clk);
 399         if (status < 0)
 400                 return status;
 401
 402         spin_lock_init(&config->lock);
 403         platform_set_drvdata(pdev, config);
 404
 405         config->rtc = rtc_device_register(pdev->name, &pdev->dev,
 406                         &spear_rtc_ops, THIS_MODULE);
 407         if (IS_ERR(config->rtc)) {
 408                 dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
 409                                 PTR_ERR(config->rtc));
 410                 status = PTR_ERR(config->rtc);
 411                 goto err_disable_clock;
 412         }
 413
 414         config->rtc->uie_unsupported = 1;
 415
 416         if (!device_can_wakeup(&pdev->dev))
 417                 device_init_wakeup(&pdev->dev, 1);
 418
 419         return 0;
 420
 421 err_disable_clock:
 422         platform_set_drvdata(pdev, NULL);
 423         clk_disable_unprepare(config->clk);
 424
 425         return status;
 426 }
 427
 428 static int spear_rtc_remove(struct platform_device *pdev)
 429 {
 430         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 431
 432         rtc_device_unregister(config->rtc);
 433         spear_rtc_disable_interrupt(config);
 434         clk_disable_unprepare(config->clk);
 435         device_init_wakeup(&pdev->dev, 0);
 436
 437         return 0;
 438 }
 439
 440 #ifdef CONFIG_PM
 441
 442 static int spear_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 443 {
 444         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 445         int irq;
 446
 447         irq = platform_get_irq(pdev, 0);
 448         if (device_may_wakeup(&pdev->dev)) {
 449                 if (!enable_irq_wake(irq))
 450                         config->irq_wake = 1;
 451         } else {
 452                 spear_rtc_disable_interrupt(config);
 453                 clk_disable(config->clk);
 454         }
 455
 456         return 0;
 457 }
 458
 459 static int spear_rtc_resume(struct platform_device *pdev)
 460 {
 461         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 462         int irq;
 463
 464         irq = platform_get_irq(pdev, 0);
 465
 466         if (device_may_wakeup(&pdev->dev)) {
 467                 if (config->irq_wake) {
 468                         disable_irq_wake(irq);
 469                         config->irq_wake = 0;
 470                 }
 471         } else {
 472                 clk_enable(config->clk);
 473                 spear_rtc_enable_interrupt(config);
 474         }
 475
 476         return 0;
 477 }
 478
 479 #else
 480 #define spear_rtc_suspend       NULL
 481 #define spear_rtc_resume        NULL
 482 #endif
 483
 484 static void spear_rtc_shutdown(struct platform_device *pdev)
 485 {
 486         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 487
 488         spear_rtc_disable_interrupt(config);
 489         clk_disable(config->clk);
 490 }
 491
 492 #ifdef CONFIG_OF
 493 static const struct of_device_id spear_rtc_id_table[] = {
 494         { .compatible = "st,spear600-rtc" },
 495         {}
 496 };
 497 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
 498 #endif
 499
 500 static struct platform_driver spear_rtc_driver = {
 501         .probe = spear_rtc_probe,
 502         .remove = spear_rtc_remove,
 503         .suspend = spear_rtc_suspend,
 504         .resume = spear_rtc_resume,
 505         .shutdown = spear_rtc_shutdown,
 506         .driver = {
 507                 .name = "rtc-spear",
 508                 .of_match_table = of_match_ptr(spear_rtc_id_table),
 509         },
 510 };
 511
 512 module_platform_driver(spear_rtc_driver);
 513
 514 MODULE_ALIAS("platform:rtc-spear");
 515 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
 516 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
 517 MODULE_LICENSE("GPL");