drivers/rtc/rtc-pl031.c

   1 /*
   2  * drivers/rtc/rtc-pl031.c
   3  *
   4  * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
   5  *
   6  * Author: Deepak Saxena <dsaxena@plexity.net>
   7  *
   8  * Copyright 2006 (c) MontaVista Software, Inc.
   9  *
  10  * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
  11  * Copyright 2010 (c) ST-Ericsson AB
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version
  16  * 2 of the License, or (at your option) any later version.
  17  */
  18 #include <linux/module.h>
  19 #include <linux/rtc.h>
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/amba/bus.h>
  23 #include <linux/io.h>
  24 #include <linux/bcd.h>
  25 #include <linux/delay.h>
  26 #include <linux/slab.h>
  27
  28 /*
  29  * Register definitions
  30  */
  31 #define RTC_DR          0x00    /* Data read register */
  32 #define RTC_MR          0x04    /* Match register */
  33 #define RTC_LR          0x08    /* Data load register */
  34 #define RTC_CR          0x0c    /* Control register */
  35 #define RTC_IMSC        0x10    /* Interrupt mask and set register */
  36 #define RTC_RIS         0x14    /* Raw interrupt status register */
  37 #define RTC_MIS         0x18    /* Masked interrupt status register */
  38 #define RTC_ICR         0x1c    /* Interrupt clear register */
  39 /* ST variants have additional timer functionality */
  40 #define RTC_TDR         0x20    /* Timer data read register */
  41 #define RTC_TLR         0x24    /* Timer data load register */
  42 #define RTC_TCR         0x28    /* Timer control register */
  43 #define RTC_YDR         0x30    /* Year data read register */
  44 #define RTC_YMR         0x34    /* Year match register */
  45 #define RTC_YLR         0x38    /* Year data load register */
  46
  47 #define RTC_CR_EN       (1 << 0)        /* counter enable bit */
  48 #define RTC_CR_CWEN     (1 << 26)       /* Clockwatch enable bit */
  49
  50 #define RTC_TCR_EN      (1 << 1) /* Periodic timer enable bit */
  51
  52 /* Common bit definitions for Interrupt status and control registers */
  53 #define RTC_BIT_AI      (1 << 0) /* Alarm interrupt bit */
  54 #define RTC_BIT_PI      (1 << 1) /* Periodic interrupt bit. ST variants only. */
  55
  56 /* Common bit definations for ST v2 for reading/writing time */
  57 #define RTC_SEC_SHIFT 0
  58 #define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
  59 #define RTC_MIN_SHIFT 6
  60 #define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
  61 #define RTC_HOUR_SHIFT 12
  62 #define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
  63 #define RTC_WDAY_SHIFT 17
  64 #define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
  65 #define RTC_MDAY_SHIFT 20
  66 #define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
  67 #define RTC_MON_SHIFT 25
  68 #define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
  69
  70 #define RTC_TIMER_FREQ 32768
  71
  72 /**
  73  * struct pl031_vendor_data - per-vendor variations
  74  * @ops: the vendor-specific operations used on this silicon version
  75  * @clockwatch: if this is an ST Microelectronics silicon version with a
  76  *      clockwatch function
  77  * @st_weekday: if this is an ST Microelectronics silicon version that need
  78  *      the weekday fix
  79  * @irqflags: special IRQ flags per variant
  80  */
  81 struct pl031_vendor_data {
  82         struct rtc_class_ops ops;
  83         bool clockwatch;
  84         bool st_weekday;
  85         unsigned long irqflags;
  86 };
  87
  88 struct pl031_local {
  89         struct pl031_vendor_data *vendor;
  90         struct rtc_device *rtc;
  91         void __iomem *base;
  92 };
  93
  94 static int pl031_alarm_irq_enable(struct device *dev,
  95         unsigned int enabled)
  96 {
  97         struct pl031_local *ldata = dev_get_drvdata(dev);
  98         unsigned long imsc;
  99
 100         /* Clear any pending alarm interrupts. */
 101         writel(RTC_BIT_AI, ldata->base + RTC_ICR);
 102
 103         imsc = readl(ldata->base + RTC_IMSC);
 104
 105         if (enabled == 1)
 106                 writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
 107         else
 108                 writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
 109
 110         return 0;
 111 }
 112
 113 /*
 114  * Convert Gregorian date to ST v2 RTC format.
 115  */
 116 static int pl031_stv2_tm_to_time(struct device *dev,
 117                                  struct rtc_time *tm, unsigned long *st_time,
 118         unsigned long *bcd_year)
 119 {
 120         int year = tm->tm_year + 1900;
 121         int wday = tm->tm_wday;
 122
 123         /* wday masking is not working in hardware so wday must be valid */
 124         if (wday < -1 || wday > 6) {
 125                 dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
 126                 return -EINVAL;
 127         } else if (wday == -1) {
 128                 /* wday is not provided, calculate it here */
 129                 unsigned long time;
 130                 struct rtc_time calc_tm;
 131
 132                 rtc_tm_to_time(tm, &time);
 133                 rtc_time_to_tm(time, &calc_tm);
 134                 wday = calc_tm.tm_wday;
 135         }
 136
 137         *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
 138
 139         *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
 140                         |       (tm->tm_mday << RTC_MDAY_SHIFT)
 141                         |       ((wday + 1) << RTC_WDAY_SHIFT)
 142                         |       (tm->tm_hour << RTC_HOUR_SHIFT)
 143                         |       (tm->tm_min << RTC_MIN_SHIFT)
 144                         |       (tm->tm_sec << RTC_SEC_SHIFT);
 145
 146         return 0;
 147 }
 148
 149 /*
 150  * Convert ST v2 RTC format to Gregorian date.
 151  */
 152 static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
 153         struct rtc_time *tm)
 154 {
 155         tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
 156         tm->tm_mon  = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
 157         tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
 158         tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
 159         tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
 160         tm->tm_min  = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
 161         tm->tm_sec  = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
 162
 163         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 164         tm->tm_year -= 1900;
 165
 166         return 0;
 167 }
 168
 169 static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
 170 {
 171         struct pl031_local *ldata = dev_get_drvdata(dev);
 172
 173         pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
 174                         readl(ldata->base + RTC_YDR), tm);
 175
 176         return 0;
 177 }
 178
 179 static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
 180 {
 181         unsigned long time;
 182         unsigned long bcd_year;
 183         struct pl031_local *ldata = dev_get_drvdata(dev);
 184         int ret;
 185
 186         ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
 187         if (ret == 0) {
 188                 writel(bcd_year, ldata->base + RTC_YLR);
 189                 writel(time, ldata->base + RTC_LR);
 190         }
 191
 192         return ret;
 193 }
 194
 195 static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 196 {
 197         struct pl031_local *ldata = dev_get_drvdata(dev);
 198         int ret;
 199
 200         ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
 201                         readl(ldata->base + RTC_YMR), &alarm->time);
 202
 203         alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
 204         alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
 205
 206         return ret;
 207 }
 208
 209 static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 210 {
 211         struct pl031_local *ldata = dev_get_drvdata(dev);
 212         unsigned long time;
 213         unsigned long bcd_year;
 214         int ret;
 215
 216         /* At the moment, we can only deal with non-wildcarded alarm times. */
 217         ret = rtc_valid_tm(&alarm->time);
 218         if (ret == 0) {
 219                 ret = pl031_stv2_tm_to_time(dev, &alarm->time,
 220                                             &time, &bcd_year);
 221                 if (ret == 0) {
 222                         writel(bcd_year, ldata->base + RTC_YMR);
 223                         writel(time, ldata->base + RTC_MR);
 224
 225                         pl031_alarm_irq_enable(dev, alarm->enabled);
 226                 }
 227         }
 228
 229         return ret;
 230 }
 231
 232 static irqreturn_t pl031_interrupt(int irq, void *dev_id)
 233 {
 234         struct pl031_local *ldata = dev_id;
 235         unsigned long rtcmis;
 236         unsigned long events = 0;
 237
 238         rtcmis = readl(ldata->base + RTC_MIS);
 239         if (rtcmis & RTC_BIT_AI) {
 240                 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
 241                 events |= (RTC_AF | RTC_IRQF);
 242                 rtc_update_irq(ldata->rtc, 1, events);
 243
 244                 return IRQ_HANDLED;
 245         }
 246
 247         return IRQ_NONE;
 248 }
 249
 250 static int pl031_read_time(struct device *dev, struct rtc_time *tm)
 251 {
 252         struct pl031_local *ldata = dev_get_drvdata(dev);
 253
 254         rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
 255
 256         return 0;
 257 }
 258
 259 static int pl031_set_time(struct device *dev, struct rtc_time *tm)
 260 {
 261         unsigned long time;
 262         struct pl031_local *ldata = dev_get_drvdata(dev);
 263         int ret;
 264
 265         ret = rtc_tm_to_time(tm, &time);
 266
 267         if (ret == 0)
 268                 writel(time, ldata->base + RTC_LR);
 269
 270         return ret;
 271 }
 272
 273 static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 274 {
 275         struct pl031_local *ldata = dev_get_drvdata(dev);
 276
 277         rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
 278
 279         alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
 280         alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
 281
 282         return 0;
 283 }
 284
 285 static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 286 {
 287         struct pl031_local *ldata = dev_get_drvdata(dev);
 288         unsigned long time;
 289         int ret;
 290
 291         /* At the moment, we can only deal with non-wildcarded alarm times. */
 292         ret = rtc_valid_tm(&alarm->time);
 293         if (ret == 0) {
 294                 ret = rtc_tm_to_time(&alarm->time, &time);
 295                 if (ret == 0) {
 296                         writel(time, ldata->base + RTC_MR);
 297                         pl031_alarm_irq_enable(dev, alarm->enabled);
 298                 }
 299         }
 300
 301         return ret;
 302 }
 303
 304 static int pl031_remove(struct amba_device *adev)
 305 {
 306         struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
 307
 308         amba_set_drvdata(adev, NULL);
 309         free_irq(adev->irq[0], ldata);
 310         rtc_device_unregister(ldata->rtc);
 311         iounmap(ldata->base);
 312         kfree(ldata);
 313         amba_release_regions(adev);
 314
 315         return 0;
 316 }
 317
 318 static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
 319 {
 320         int ret;
 321         struct pl031_local *ldata;
 322         struct pl031_vendor_data *vendor = id->data;
 323         struct rtc_class_ops *ops = &vendor->ops;
 324         unsigned long time, data;
 325
 326         ret = amba_request_regions(adev, NULL);
 327         if (ret)
 328                 goto err_req;
 329
 330         ldata = kzalloc(sizeof(struct pl031_local), GFP_KERNEL);
 331         if (!ldata) {
 332                 ret = -ENOMEM;
 333                 goto out;
 334         }
 335         ldata->vendor = vendor;
 336
 337         ldata->base = ioremap(adev->res.start, resource_size(&adev->res));
 338
 339         if (!ldata->base) {
 340                 ret = -ENOMEM;
 341                 goto out_no_remap;
 342         }
 343
 344         amba_set_drvdata(adev, ldata);
 345
 346         dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
 347         dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
 348
 349         data = readl(ldata->base + RTC_CR);
 350         /* Enable the clockwatch on ST Variants */
 351         if (vendor->clockwatch)
 352                 data |= RTC_CR_CWEN;
 353         else
 354                 data |= RTC_CR_EN;
 355         writel(data, ldata->base + RTC_CR);
 356
 357         /*
 358          * On ST PL031 variants, the RTC reset value does not provide correct
 359          * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
 360          */
 361         if (vendor->st_weekday) {
 362                 if (readl(ldata->base + RTC_YDR) == 0x2000) {
 363                         time = readl(ldata->base + RTC_DR);
 364                         if ((time &
 365                              (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
 366                             == 0x02120000) {
 367                                 time = time | (0x7 << RTC_WDAY_SHIFT);
 368                                 writel(0x2000, ldata->base + RTC_YLR);
 369                                 writel(time, ldata->base + RTC_LR);
 370                         }
 371                 }
 372         }
 373
 374         ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
 375                                         THIS_MODULE);
 376         if (IS_ERR(ldata->rtc)) {
 377                 ret = PTR_ERR(ldata->rtc);
 378                 goto out_no_rtc;
 379         }
 380
 381         if (request_irq(adev->irq[0], pl031_interrupt,
 382                         vendor->irqflags, "rtc-pl031", ldata)) {
 383                 ret = -EIO;
 384                 goto out_no_irq;
 385         }
 386
 387         device_init_wakeup(&adev->dev, 1);
 388
 389         return 0;
 390
 391 out_no_irq:
 392         rtc_device_unregister(ldata->rtc);
 393 out_no_rtc:
 394         iounmap(ldata->base);
 395         amba_set_drvdata(adev, NULL);
 396 out_no_remap:
 397         kfree(ldata);
 398 out:
 399         amba_release_regions(adev);
 400 err_req:
 401
 402         return ret;
 403 }
 404
 405 /* Operations for the original ARM version */
 406 static struct pl031_vendor_data arm_pl031 = {
 407         .ops = {
 408                 .read_time = pl031_read_time,
 409                 .set_time = pl031_set_time,
 410                 .read_alarm = pl031_read_alarm,
 411                 .set_alarm = pl031_set_alarm,
 412                 .alarm_irq_enable = pl031_alarm_irq_enable,
 413         },
 414         .irqflags = IRQF_NO_SUSPEND,
 415 };
 416
 417 /* The First ST derivative */
 418 static struct pl031_vendor_data stv1_pl031 = {
 419         .ops = {
 420                 .read_time = pl031_read_time,
 421                 .set_time = pl031_set_time,
 422                 .read_alarm = pl031_read_alarm,
 423                 .set_alarm = pl031_set_alarm,
 424                 .alarm_irq_enable = pl031_alarm_irq_enable,
 425         },
 426         .clockwatch = true,
 427         .st_weekday = true,
 428         .irqflags = IRQF_NO_SUSPEND,
 429 };
 430
 431 /* And the second ST derivative */
 432 static struct pl031_vendor_data stv2_pl031 = {
 433         .ops = {
 434                 .read_time = pl031_stv2_read_time,
 435                 .set_time = pl031_stv2_set_time,
 436                 .read_alarm = pl031_stv2_read_alarm,
 437                 .set_alarm = pl031_stv2_set_alarm,
 438                 .alarm_irq_enable = pl031_alarm_irq_enable,
 439         },
 440         .clockwatch = true,
 441         .st_weekday = true,
 442         /*
 443          * This variant shares the IRQ with another block and must not
 444          * suspend that IRQ line.
 445          */
 446         .irqflags = IRQF_SHARED | IRQF_NO_SUSPEND,
 447 };
 448
 449 static struct amba_id pl031_ids[] = {
 450         {
 451                 .id = 0x00041031,
 452                 .mask = 0x000fffff,
 453                 .data = &arm_pl031,
 454         },
 455         /* ST Micro variants */
 456         {
 457                 .id = 0x00180031,
 458                 .mask = 0x00ffffff,
 459                 .data = &stv1_pl031,
 460         },
 461         {
 462                 .id = 0x00280031,
 463                 .mask = 0x00ffffff,
 464                 .data = &stv2_pl031,
 465         },
 466         {0, 0},
 467 };
 468
 469 MODULE_DEVICE_TABLE(amba, pl031_ids);
 470
 471 static struct amba_driver pl031_driver = {
 472         .drv = {
 473                 .name = "rtc-pl031",
 474         },
 475         .id_table = pl031_ids,
 476         .probe = pl031_probe,
 477         .remove = pl031_remove,
 478 };
 479
 480 module_amba_driver(pl031_driver);
 481
 482 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
 483 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
 484 MODULE_LICENSE("GPL");