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