drivers/rtc/rtc-spear.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * drivers/rtc/rtc-spear.c
   4  *
   5  * Copyright (C) 2010 ST Microelectronics
   6  * Rajeev Kumar<rajeev-dlh.kumar@st.com>
   7  */
   8
   9 #include <linux/bcd.h>
  10 #include <linux/clk.h>
  11 #include <linux/delay.h>
  12 #include <linux/init.h>
  13 #include <linux/io.h>
  14 #include <linux/irq.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/rtc.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21
  22 /* RTC registers */
  23 #define TIME_REG                0x00
  24 #define DATE_REG                0x04
  25 #define ALARM_TIME_REG          0x08
  26 #define ALARM_DATE_REG          0x0C
  27 #define CTRL_REG                0x10
  28 #define STATUS_REG              0x14
  29
  30 /* TIME_REG & ALARM_TIME_REG */
  31 #define SECONDS_UNITS           (0xf<<0)        /* seconds units position */
  32 #define SECONDS_TENS            (0x7<<4)        /* seconds tens position */
  33 #define MINUTES_UNITS           (0xf<<8)        /* minutes units position */
  34 #define MINUTES_TENS            (0x7<<12)       /* minutes tens position */
  35 #define HOURS_UNITS             (0xf<<16)       /* hours units position */
  36 #define HOURS_TENS              (0x3<<20)       /* hours tens position */
  37
  38 /* DATE_REG & ALARM_DATE_REG */
  39 #define DAYS_UNITS              (0xf<<0)        /* days units position */
  40 #define DAYS_TENS               (0x3<<4)        /* days tens position */
  41 #define MONTHS_UNITS            (0xf<<8)        /* months units position */
  42 #define MONTHS_TENS             (0x1<<12)       /* months tens position */
  43 #define YEARS_UNITS             (0xf<<16)       /* years units position */
  44 #define YEARS_TENS              (0xf<<20)       /* years tens position */
  45 #define YEARS_HUNDREDS          (0xf<<24)       /* years hundereds position */
  46 #define YEARS_MILLENIUMS        (0xf<<28)       /* years millenium position */
  47
  48 /* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
  49 #define SECOND_SHIFT            0x00            /* seconds units */
  50 #define MINUTE_SHIFT            0x08            /* minutes units position */
  51 #define HOUR_SHIFT              0x10            /* hours units position */
  52 #define MDAY_SHIFT              0x00            /* Month day shift */
  53 #define MONTH_SHIFT             0x08            /* Month shift */
  54 #define YEAR_SHIFT              0x10            /* Year shift */
  55
  56 #define SECOND_MASK             0x7F
  57 #define MIN_MASK                0x7F
  58 #define HOUR_MASK               0x3F
  59 #define DAY_MASK                0x3F
  60 #define MONTH_MASK              0x7F
  61 #define YEAR_MASK               0xFFFF
  62
  63 /* date reg equal to time reg, for debug only */
  64 #define TIME_BYP                (1<<9)
  65 #define INT_ENABLE              (1<<31)         /* interrupt enable */
  66
  67 /* STATUS_REG */
  68 #define CLK_UNCONNECTED         (1<<0)
  69 #define PEND_WR_TIME            (1<<2)
  70 #define PEND_WR_DATE            (1<<3)
  71 #define LOST_WR_TIME            (1<<4)
  72 #define LOST_WR_DATE            (1<<5)
  73 #define RTC_INT_MASK            (1<<31)
  74 #define STATUS_BUSY             (PEND_WR_TIME | PEND_WR_DATE)
  75 #define STATUS_FAIL             (LOST_WR_TIME | LOST_WR_DATE)
  76
  77 struct spear_rtc_config {
  78         struct rtc_device *rtc;
  79         struct clk *clk;
  80         spinlock_t lock;
  81         void __iomem *ioaddr;
  82         unsigned int irq_wake;
  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 spear_rtc_config *config = dev_id;
 153         unsigned long events = 0;
 154         unsigned int irq_data;
 155
 156         spin_lock(&config->lock);
 157         irq_data = readl(config->ioaddr + STATUS_REG);
 158         spin_unlock(&config->lock);
 159
 160         if ((irq_data & RTC_INT_MASK)) {
 161                 spear_rtc_clear_interrupt(config);
 162                 events = RTC_IRQF | RTC_AF;
 163                 rtc_update_irq(config->rtc, 1, events);
 164                 return IRQ_HANDLED;
 165         } else
 166                 return IRQ_NONE;
 167
 168 }
 169
 170 static void tm2bcd(struct rtc_time *tm)
 171 {
 172         tm->tm_sec = bin2bcd(tm->tm_sec);
 173         tm->tm_min = bin2bcd(tm->tm_min);
 174         tm->tm_hour = bin2bcd(tm->tm_hour);
 175         tm->tm_mday = bin2bcd(tm->tm_mday);
 176         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 177         tm->tm_year = bin2bcd(tm->tm_year);
 178 }
 179
 180 static void bcd2tm(struct rtc_time *tm)
 181 {
 182         tm->tm_sec = bcd2bin(tm->tm_sec);
 183         tm->tm_min = bcd2bin(tm->tm_min);
 184         tm->tm_hour = bcd2bin(tm->tm_hour);
 185         tm->tm_mday = bcd2bin(tm->tm_mday);
 186         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 187         /* epoch == 1900 */
 188         tm->tm_year = bcd2bin(tm->tm_year);
 189 }
 190
 191 /*
 192  * spear_rtc_read_time - set the time
 193  * @dev: rtc device in use
 194  * @tm: holds date and time
 195  *
 196  * This function read time and date. On success it will return 0
 197  * otherwise -ve error is returned.
 198  */
 199 static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
 200 {
 201         struct spear_rtc_config *config = dev_get_drvdata(dev);
 202         unsigned int time, date;
 203
 204         /* we don't report wday/yday/isdst ... */
 205         rtc_wait_not_busy(config);
 206
 207         do {
 208                 time = readl(config->ioaddr + TIME_REG);
 209                 date = readl(config->ioaddr + DATE_REG);
 210         } while (time == readl(config->ioaddr + TIME_REG));
 211         tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
 212         tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
 213         tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
 214         tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
 215         tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
 216         tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
 217
 218         bcd2tm(tm);
 219         return 0;
 220 }
 221
 222 /*
 223  * spear_rtc_set_time - set the time
 224  * @dev: rtc device in use
 225  * @tm: holds date and time
 226  *
 227  * This function set time and date. On success it will return 0
 228  * otherwise -ve error is returned.
 229  */
 230 static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
 231 {
 232         struct spear_rtc_config *config = dev_get_drvdata(dev);
 233         unsigned int time, date;
 234
 235         tm2bcd(tm);
 236
 237         rtc_wait_not_busy(config);
 238         time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
 239                 (tm->tm_hour << HOUR_SHIFT);
 240         date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
 241                 (tm->tm_year << YEAR_SHIFT);
 242         writel(time, config->ioaddr + TIME_REG);
 243         writel(date, config->ioaddr + DATE_REG);
 244
 245         return is_write_complete(config);
 246 }
 247
 248 /*
 249  * spear_rtc_read_alarm - read the alarm time
 250  * @dev: rtc device in use
 251  * @alm: holds alarm date and time
 252  *
 253  * This function read alarm time and date. On success it will return 0
 254  * otherwise -ve error is returned.
 255  */
 256 static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 257 {
 258         struct spear_rtc_config *config = dev_get_drvdata(dev);
 259         unsigned int time, date;
 260
 261         rtc_wait_not_busy(config);
 262
 263         time = readl(config->ioaddr + ALARM_TIME_REG);
 264         date = readl(config->ioaddr + ALARM_DATE_REG);
 265         alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
 266         alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
 267         alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
 268         alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
 269         alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
 270         alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
 271
 272         bcd2tm(&alm->time);
 273         alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
 274
 275         return 0;
 276 }
 277
 278 /*
 279  * spear_rtc_set_alarm - set the alarm time
 280  * @dev: rtc device in use
 281  * @alm: holds alarm date and time
 282  *
 283  * This function set alarm time and date. On success it will return 0
 284  * otherwise -ve error is returned.
 285  */
 286 static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 287 {
 288         struct spear_rtc_config *config = dev_get_drvdata(dev);
 289         unsigned int time, date;
 290         int err;
 291
 292         tm2bcd(&alm->time);
 293
 294         rtc_wait_not_busy(config);
 295
 296         time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
 297                         MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);
 298         date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
 299                         MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
 300
 301         writel(time, config->ioaddr + ALARM_TIME_REG);
 302         writel(date, config->ioaddr + ALARM_DATE_REG);
 303         err = is_write_complete(config);
 304         if (err < 0)
 305                 return err;
 306
 307         if (alm->enabled)
 308                 spear_rtc_enable_interrupt(config);
 309         else
 310                 spear_rtc_disable_interrupt(config);
 311
 312         return 0;
 313 }
 314
 315 static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
 316 {
 317         struct spear_rtc_config *config = dev_get_drvdata(dev);
 318         int ret = 0;
 319
 320         spear_rtc_clear_interrupt(config);
 321
 322         switch (enabled) {
 323         case 0:
 324                 /* alarm off */
 325                 spear_rtc_disable_interrupt(config);
 326                 break;
 327         case 1:
 328                 /* alarm on */
 329                 spear_rtc_enable_interrupt(config);
 330                 break;
 331         default:
 332                 ret = -EINVAL;
 333                 break;
 334         }
 335
 336         return ret;
 337 }
 338
 339 static const struct rtc_class_ops spear_rtc_ops = {
 340         .read_time = spear_rtc_read_time,
 341         .set_time = spear_rtc_set_time,
 342         .read_alarm = spear_rtc_read_alarm,
 343         .set_alarm = spear_rtc_set_alarm,
 344         .alarm_irq_enable = spear_alarm_irq_enable,
 345 };
 346
 347 static int spear_rtc_probe(struct platform_device *pdev)
 348 {
 349         struct spear_rtc_config *config;
 350         int status = 0;
 351         int irq;
 352
 353         config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
 354         if (!config)
 355                 return -ENOMEM;
 356
 357         config->rtc = devm_rtc_allocate_device(&pdev->dev);
 358         if (IS_ERR(config->rtc))
 359                 return PTR_ERR(config->rtc);
 360
 361         /* alarm irqs */
 362         irq = platform_get_irq(pdev, 0);
 363         if (irq < 0)
 364                 return irq;
 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         config->ioaddr = devm_platform_ioremap_resource(pdev, 0);
 375         if (IS_ERR(config->ioaddr))
 376                 return PTR_ERR(config->ioaddr);
 377
 378         config->clk = devm_clk_get(&pdev->dev, NULL);
 379         if (IS_ERR(config->clk))
 380                 return PTR_ERR(config->clk);
 381
 382         status = clk_prepare_enable(config->clk);
 383         if (status < 0)
 384                 return status;
 385
 386         spin_lock_init(&config->lock);
 387         platform_set_drvdata(pdev, config);
 388
 389         config->rtc->ops = &spear_rtc_ops;
 390         config->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
 391         config->rtc->range_max = RTC_TIMESTAMP_END_9999;
 392
 393         status = devm_rtc_register_device(config->rtc);
 394         if (status)
 395                 goto err_disable_clock;
 396
 397         if (!device_can_wakeup(&pdev->dev))
 398                 device_init_wakeup(&pdev->dev, 1);
 399
 400         return 0;
 401
 402 err_disable_clock:
 403         clk_disable_unprepare(config->clk);
 404
 405         return status;
 406 }
 407
 408 static void spear_rtc_remove(struct platform_device *pdev)
 409 {
 410         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 411
 412         spear_rtc_disable_interrupt(config);
 413         clk_disable_unprepare(config->clk);
 414         device_init_wakeup(&pdev->dev, 0);
 415 }
 416
 417 #ifdef CONFIG_PM_SLEEP
 418 static int spear_rtc_suspend(struct device *dev)
 419 {
 420         struct platform_device *pdev = to_platform_device(dev);
 421         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 422         int irq;
 423
 424         irq = platform_get_irq(pdev, 0);
 425         if (device_may_wakeup(&pdev->dev)) {
 426                 if (!enable_irq_wake(irq))
 427                         config->irq_wake = 1;
 428         } else {
 429                 spear_rtc_disable_interrupt(config);
 430                 clk_disable(config->clk);
 431         }
 432
 433         return 0;
 434 }
 435
 436 static int spear_rtc_resume(struct device *dev)
 437 {
 438         struct platform_device *pdev = to_platform_device(dev);
 439         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 440         int irq;
 441
 442         irq = platform_get_irq(pdev, 0);
 443
 444         if (device_may_wakeup(&pdev->dev)) {
 445                 if (config->irq_wake) {
 446                         disable_irq_wake(irq);
 447                         config->irq_wake = 0;
 448                 }
 449         } else {
 450                 clk_enable(config->clk);
 451                 spear_rtc_enable_interrupt(config);
 452         }
 453
 454         return 0;
 455 }
 456 #endif
 457
 458 static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
 459
 460 static void spear_rtc_shutdown(struct platform_device *pdev)
 461 {
 462         struct spear_rtc_config *config = platform_get_drvdata(pdev);
 463
 464         spear_rtc_disable_interrupt(config);
 465         clk_disable(config->clk);
 466 }
 467
 468 #ifdef CONFIG_OF
 469 static const struct of_device_id spear_rtc_id_table[] = {
 470         { .compatible = "st,spear600-rtc" },
 471         {}
 472 };
 473 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
 474 #endif
 475
 476 static struct platform_driver spear_rtc_driver = {
 477         .probe = spear_rtc_probe,
 478         .remove = spear_rtc_remove,
 479         .shutdown = spear_rtc_shutdown,
 480         .driver = {
 481                 .name = "rtc-spear",
 482                 .pm = &spear_rtc_pm_ops,
 483                 .of_match_table = of_match_ptr(spear_rtc_id_table),
 484         },
 485 };
 486
 487 module_platform_driver(spear_rtc_driver);
 488
 489 MODULE_ALIAS("platform:rtc-spear");
 490 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
 491 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
 492 MODULE_LICENSE("GPL");