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