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/platform_device.h>
  20 #include <linux/rtc.h>
  21 #include <linux/slab.h>
  22 #include <linux/spinlock.h>
  23
  24 /* RTC registers */
  25 #define TIME_REG                0x00
  26 #define DATE_REG                0x04
  27 #define ALARM_TIME_REG          0x08
  28 #define ALARM_DATE_REG          0x0C
  29 #define CTRL_REG                0x10
  30 #define STATUS_REG              0x14
  31
  32 /* TIME_REG & ALARM_TIME_REG */
  33 #define SECONDS_UNITS           (0xf<<0)        /* seconds units position */
  34 #define SECONDS_TENS            (0x7<<4)        /* seconds tens position */
  35 #define MINUTES_UNITS           (0xf<<8)        /* minutes units position */
  36 #define MINUTES_TENS            (0x7<<12)       /* minutes tens position */
  37 #define HOURS_UNITS             (0xf<<16)       /* hours units position */
  38 #define HOURS_TENS              (0x3<<20)       /* hours tens position */
  39
  40 /* DATE_REG & ALARM_DATE_REG */
  41 #define DAYS_UNITS              (0xf<<0)        /* days units position */
  42 #define DAYS_TENS               (0x3<<4)        /* days tens position */
  43 #define MONTHS_UNITS            (0xf<<8)        /* months units position */
  44 #define MONTHS_TENS             (0x1<<12)       /* months tens position */
  45 #define YEARS_UNITS             (0xf<<16)       /* years units position */
  46 #define YEARS_TENS              (0xf<<20)       /* years tens position */
  47 #define YEARS_HUNDREDS          (0xf<<24)       /* years hundereds position */
  48 #define YEARS_MILLENIUMS        (0xf<<28)       /* years millenium position */
  49
  50 /* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
  51 #define SECOND_SHIFT            0x00            /* seconds units */
  52 #define MINUTE_SHIFT            0x08            /* minutes units position */
  53 #define HOUR_SHIFT              0x10            /* hours units position */
  54 #define MDAY_SHIFT              0x00            /* Month day shift */
  55 #define MONTH_SHIFT             0x08            /* Month shift */
  56 #define YEAR_SHIFT              0x10            /* Year shift */
  57
  58 #define SECOND_MASK             0x7F
  59 #define MIN_MASK                0x7F
  60 #define HOUR_MASK               0x3F
  61 #define DAY_MASK                0x3F
  62 #define MONTH_MASK              0x7F
  63 #define YEAR_MASK               0xFFFF
  64
  65 /* date reg equal to time reg, for debug only */
  66 #define TIME_BYP                (1<<9)
  67 #define INT_ENABLE              (1<<31)         /* interrupt enable */
  68
  69 /* STATUS_REG */
  70 #define CLK_UNCONNECTED         (1<<0)
  71 #define PEND_WR_TIME            (1<<2)
  72 #define PEND_WR_DATE            (1<<3)
  73 #define LOST_WR_TIME            (1<<4)
  74 #define LOST_WR_DATE            (1<<5)
  75 #define RTC_INT_MASK            (1<<31)
  76 #define STATUS_BUSY             (PEND_WR_TIME | PEND_WR_DATE)
  77 #define STATUS_FAIL             (LOST_WR_TIME | LOST_WR_DATE)
  78
  79 struct spear_rtc_config {
  80         struct clk *clk;
  81         spinlock_t lock;
  82         void __iomem *ioaddr;
  83 };
  84
  85 static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
  86 {
  87         unsigned int val;
  88         unsigned long flags;
  89
  90         spin_lock_irqsave(&config->lock, flags);
  91         val = readl(config->ioaddr + STATUS_REG);
  92         val |= RTC_INT_MASK;
  93         writel(val, config->ioaddr + STATUS_REG);
  94         spin_unlock_irqrestore(&config->lock, flags);
  95 }
  96
  97 static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
  98 {
  99         unsigned int val;
 100
 101         val = readl(config->ioaddr + CTRL_REG);
 102         if (!(val & INT_ENABLE)) {
 103                 spear_rtc_clear_interrupt(config);
 104                 val |= INT_ENABLE;
 105                 writel(val, config->ioaddr + CTRL_REG);
 106         }
 107 }
 108
 109 static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
 110 {
 111         unsigned int val;
 112
 113         val = readl(config->ioaddr + CTRL_REG);
 114         if (val & INT_ENABLE) {
 115                 val &= ~INT_ENABLE;
 116                 writel(val, config->ioaddr + CTRL_REG);
 117         }
 118 }
 119
 120 static inline int is_write_complete(struct spear_rtc_config *config)
 121 {
 122         int ret = 0;
 123         unsigned long flags;
 124
 125         spin_lock_irqsave(&config->lock, flags);
 126         if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
 127                 ret = -EIO;
 128         spin_unlock_irqrestore(&config->lock, flags);
 129
 130         return ret;
 131 }
 132
 133 static void rtc_wait_not_busy(struct spear_rtc_config *config)
 134 {
 135         int status, count = 0;
 136         unsigned long flags;
 137
 138         /* Assuming BUSY may stay active for 80 msec) */
 139         for (count = 0; count < 80; count++) {
 140                 spin_lock_irqsave(&config->lock, flags);
 141                 status = readl(config->ioaddr + STATUS_REG);
 142                 spin_unlock_irqrestore(&config->lock, flags);
 143                 if ((status & STATUS_BUSY) == 0)
 144                         break;
 145                 /* check status busy, after each msec */
 146                 msleep(1);
 147         }
 148 }
 149
 150 static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
 151 {
 152         struct rtc_device *rtc = (struct rtc_device *)dev_id;
 153         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 154         unsigned long flags, events = 0;
 155         unsigned int irq_data;
 156
 157         spin_lock_irqsave(&config->lock, flags);
 158         irq_data = readl(config->ioaddr + STATUS_REG);
 159         spin_unlock_irqrestore(&config->lock, flags);
 160
 161         if ((irq_data & RTC_INT_MASK)) {
 162                 spear_rtc_clear_interrupt(config);
 163                 events = RTC_IRQF | RTC_AF;
 164                 rtc_update_irq(rtc, 1, events);
 165                 return IRQ_HANDLED;
 166         } else
 167                 return IRQ_NONE;
 168
 169 }
 170
 171 static int tm2bcd(struct rtc_time *tm)
 172 {
 173         if (rtc_valid_tm(tm) != 0)
 174                 return -EINVAL;
 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         return 0;
 183 }
 184
 185 static void bcd2tm(struct rtc_time *tm)
 186 {
 187         tm->tm_sec = bcd2bin(tm->tm_sec);
 188         tm->tm_min = bcd2bin(tm->tm_min);
 189         tm->tm_hour = bcd2bin(tm->tm_hour);
 190         tm->tm_mday = bcd2bin(tm->tm_mday);
 191         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 192         /* epoch == 1900 */
 193         tm->tm_year = bcd2bin(tm->tm_year);
 194 }
 195
 196 /*
 197  * spear_rtc_read_time - set the time
 198  * @dev: rtc device in use
 199  * @tm: holds date and time
 200  *
 201  * This function read time and date. On success it will return 0
 202  * otherwise -ve error is returned.
 203  */
 204 static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
 205 {
 206         struct platform_device *pdev = to_platform_device(dev);
 207         struct rtc_device *rtc = platform_get_drvdata(pdev);
 208         struct spear_rtc_config *config = dev_get_drvdata(&rtc->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 platform_device *pdev = to_platform_device(dev);
 238         struct rtc_device *rtc = platform_get_drvdata(pdev);
 239         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 240         unsigned int time, date, err = 0;
 241
 242         if (tm2bcd(tm) < 0)
 243                 return -EINVAL;
 244
 245         rtc_wait_not_busy(config);
 246         time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
 247                 (tm->tm_hour << HOUR_SHIFT);
 248         date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
 249                 (tm->tm_year << YEAR_SHIFT);
 250         writel(time, config->ioaddr + TIME_REG);
 251         writel(date, config->ioaddr + DATE_REG);
 252         err = is_write_complete(config);
 253         if (err < 0)
 254                 return err;
 255
 256         return 0;
 257 }
 258
 259 /*
 260  * spear_rtc_read_alarm - read the alarm time
 261  * @dev: rtc device in use
 262  * @alm: holds alarm date and time
 263  *
 264  * This function read alarm time and date. On success it will return 0
 265  * otherwise -ve error is returned.
 266  */
 267 static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 268 {
 269         struct platform_device *pdev = to_platform_device(dev);
 270         struct rtc_device *rtc = platform_get_drvdata(pdev);
 271         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 272         unsigned int time, date;
 273
 274         rtc_wait_not_busy(config);
 275
 276         time = readl(config->ioaddr + ALARM_TIME_REG);
 277         date = readl(config->ioaddr + ALARM_DATE_REG);
 278         alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
 279         alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
 280         alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
 281         alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
 282         alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
 283         alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
 284
 285         bcd2tm(&alm->time);
 286         alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
 287
 288         return 0;
 289 }
 290
 291 /*
 292  * spear_rtc_set_alarm - set the alarm time
 293  * @dev: rtc device in use
 294  * @alm: holds alarm date and time
 295  *
 296  * This function set alarm time and date. On success it will return 0
 297  * otherwise -ve error is returned.
 298  */
 299 static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 300 {
 301         struct platform_device *pdev = to_platform_device(dev);
 302         struct rtc_device *rtc = platform_get_drvdata(pdev);
 303         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 304         unsigned int time, date, err = 0;
 305
 306         if (tm2bcd(&alm->time) < 0)
 307                 return -EINVAL;
 308
 309         rtc_wait_not_busy(config);
 310
 311         time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
 312                         MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);
 313         date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
 314                         MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
 315
 316         writel(time, config->ioaddr + ALARM_TIME_REG);
 317         writel(date, config->ioaddr + ALARM_DATE_REG);
 318         err = is_write_complete(config);
 319         if (err < 0)
 320                 return err;
 321
 322         if (alm->enabled)
 323                 spear_rtc_enable_interrupt(config);
 324         else
 325                 spear_rtc_disable_interrupt(config);
 326
 327         return 0;
 328 }
 329 static struct rtc_class_ops spear_rtc_ops = {
 330         .read_time = spear_rtc_read_time,
 331         .set_time = spear_rtc_set_time,
 332         .read_alarm = spear_rtc_read_alarm,
 333         .set_alarm = spear_rtc_set_alarm,
 334 };
 335
 336 static int __devinit spear_rtc_probe(struct platform_device *pdev)
 337 {
 338         struct resource *res;
 339         struct rtc_device *rtc;
 340         struct spear_rtc_config *config;
 341         unsigned int status = 0;
 342         int irq;
 343
 344         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 345         if (!res) {
 346                 dev_err(&pdev->dev, "no resource defined\n");
 347                 return -EBUSY;
 348         }
 349         if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
 350                 dev_err(&pdev->dev, "rtc region already claimed\n");
 351                 return -EBUSY;
 352         }
 353
 354         config = kzalloc(sizeof(*config), GFP_KERNEL);
 355         if (!config) {
 356                 dev_err(&pdev->dev, "out of memory\n");
 357                 status = -ENOMEM;
 358                 goto err_release_region;
 359         }
 360
 361         config->clk = clk_get(&pdev->dev, NULL);
 362         if (IS_ERR(config->clk)) {
 363                 status = PTR_ERR(config->clk);
 364                 goto err_kfree;
 365         }
 366
 367         status = clk_enable(config->clk);
 368         if (status < 0)
 369                 goto err_clk_put;
 370
 371         config->ioaddr = ioremap(res->start, resource_size(res));
 372         if (!config->ioaddr) {
 373                 dev_err(&pdev->dev, "ioremap fail\n");
 374                 status = -ENOMEM;
 375                 goto err_disable_clock;
 376         }
 377
 378         spin_lock_init(&config->lock);
 379
 380         rtc = rtc_device_register(pdev->name, &pdev->dev, &spear_rtc_ops,
 381                         THIS_MODULE);
 382         if (IS_ERR(rtc)) {
 383                 dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
 384                                 PTR_ERR(rtc));
 385                 status = PTR_ERR(rtc);
 386                 goto err_iounmap;
 387         }
 388
 389         platform_set_drvdata(pdev, rtc);
 390         dev_set_drvdata(&rtc->dev, config);
 391
 392         /* alarm irqs */
 393         irq = platform_get_irq(pdev, 0);
 394         if (irq < 0) {
 395                 dev_err(&pdev->dev, "no update irq?\n");
 396                 status = irq;
 397                 goto err_clear_platdata;
 398         }
 399
 400         status = request_irq(irq, spear_rtc_irq, 0, pdev->name, rtc);
 401         if (status) {
 402                 dev_err(&pdev->dev, "Alarm interrupt IRQ%d already \
 403                                 claimed\n", irq);
 404                 goto err_clear_platdata;
 405         }
 406
 407         if (!device_can_wakeup(&pdev->dev))
 408                 device_init_wakeup(&pdev->dev, 1);
 409
 410         return 0;
 411
 412 err_clear_platdata:
 413         platform_set_drvdata(pdev, NULL);
 414         dev_set_drvdata(&rtc->dev, NULL);
 415         rtc_device_unregister(rtc);
 416 err_iounmap:
 417         iounmap(config->ioaddr);
 418 err_disable_clock:
 419         clk_disable(config->clk);
 420 err_clk_put:
 421         clk_put(config->clk);
 422 err_kfree:
 423         kfree(config);
 424 err_release_region:
 425         release_mem_region(res->start, resource_size(res));
 426
 427         return status;
 428 }
 429
 430 static int __devexit spear_rtc_remove(struct platform_device *pdev)
 431 {
 432         struct rtc_device *rtc = platform_get_drvdata(pdev);
 433         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 434         int irq;
 435         struct resource *res;
 436
 437         /* leave rtc running, but disable irqs */
 438         spear_rtc_disable_interrupt(config);
 439         device_init_wakeup(&pdev->dev, 0);
 440         irq = platform_get_irq(pdev, 0);
 441         if (irq)
 442                 free_irq(irq, pdev);
 443         clk_disable(config->clk);
 444         clk_put(config->clk);
 445         iounmap(config->ioaddr);
 446         kfree(config);
 447         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 448         if (res)
 449                 release_mem_region(res->start, resource_size(res));
 450         platform_set_drvdata(pdev, NULL);
 451         dev_set_drvdata(&rtc->dev, NULL);
 452         rtc_device_unregister(rtc);
 453
 454         return 0;
 455 }
 456
 457 #ifdef CONFIG_PM
 458
 459 static int spear_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 460 {
 461         struct rtc_device *rtc = platform_get_drvdata(pdev);
 462         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 463         int irq;
 464
 465         irq = platform_get_irq(pdev, 0);
 466         if (device_may_wakeup(&pdev->dev))
 467                 enable_irq_wake(irq);
 468         else {
 469                 spear_rtc_disable_interrupt(config);
 470                 clk_disable(config->clk);
 471         }
 472
 473         return 0;
 474 }
 475
 476 static int spear_rtc_resume(struct platform_device *pdev)
 477 {
 478         struct rtc_device *rtc = platform_get_drvdata(pdev);
 479         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 480         int irq;
 481
 482         irq = platform_get_irq(pdev, 0);
 483
 484         if (device_may_wakeup(&pdev->dev))
 485                 disable_irq_wake(irq);
 486         else {
 487                 clk_enable(config->clk);
 488                 spear_rtc_enable_interrupt(config);
 489         }
 490
 491         return 0;
 492 }
 493
 494 #else
 495 #define spear_rtc_suspend       NULL
 496 #define spear_rtc_resume        NULL
 497 #endif
 498
 499 static void spear_rtc_shutdown(struct platform_device *pdev)
 500 {
 501         struct rtc_device *rtc = platform_get_drvdata(pdev);
 502         struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
 503
 504         spear_rtc_disable_interrupt(config);
 505         clk_disable(config->clk);
 506 }
 507
 508 static struct platform_driver spear_rtc_driver = {
 509         .probe = spear_rtc_probe,
 510         .remove = __devexit_p(spear_rtc_remove),
 511         .suspend = spear_rtc_suspend,
 512         .resume = spear_rtc_resume,
 513         .shutdown = spear_rtc_shutdown,
 514         .driver = {
 515                 .name = "rtc-spear",
 516         },
 517 };
 518
 519 module_platform_driver(spear_rtc_driver);
 520
 521 MODULE_ALIAS("platform:rtc-spear");
 522 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
 523 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
 524 MODULE_LICENSE("GPL");