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/pm_wakeirq.h>
  27 #include <linux/slab.h>
  28
  29 /*
  30  * Register definitions
  31  */
  32 #define RTC_DR          0x00    /* Data read register */
  33 #define RTC_MR          0x04    /* Match register */
  34 #define RTC_LR          0x08    /* Data load register */
  35 #define RTC_CR          0x0c    /* Control register */
  36 #define RTC_IMSC        0x10    /* Interrupt mask and set register */
  37 #define RTC_RIS         0x14    /* Raw interrupt status register */
  38 #define RTC_MIS         0x18    /* Masked interrupt status register */
  39 #define RTC_ICR         0x1c    /* Interrupt clear register */
  40 /* ST variants have additional timer functionality */
  41 #define RTC_TDR         0x20    /* Timer data read register */
  42 #define RTC_TLR         0x24    /* Timer data load register */
  43 #define RTC_TCR         0x28    /* Timer control register */
  44 #define RTC_YDR         0x30    /* Year data read register */
  45 #define RTC_YMR         0x34    /* Year match register */
  46 #define RTC_YLR         0x38    /* Year data load register */
  47
  48 #define RTC_CR_EN       (1 << 0)        /* counter enable bit */
  49 #define RTC_CR_CWEN     (1 << 26)       /* Clockwatch enable bit */
  50
  51 #define RTC_TCR_EN      (1 << 1) /* Periodic timer enable bit */
  52
  53 /* Common bit definitions for Interrupt status and control registers */
  54 #define RTC_BIT_AI      (1 << 0) /* Alarm interrupt bit */
  55 #define RTC_BIT_PI      (1 << 1) /* Periodic interrupt bit. ST variants only. */
  56
  57 /* Common bit definations for ST v2 for reading/writing time */
  58 #define RTC_SEC_SHIFT 0
  59 #define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
  60 #define RTC_MIN_SHIFT 6
  61 #define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
  62 #define RTC_HOUR_SHIFT 12
  63 #define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
  64 #define RTC_WDAY_SHIFT 17
  65 #define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
  66 #define RTC_MDAY_SHIFT 20
  67 #define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
  68 #define RTC_MON_SHIFT 25
  69 #define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
  70
  71 #define RTC_TIMER_FREQ 32768
  72
  73 /**
  74  * struct pl031_vendor_data - per-vendor variations
  75  * @ops: the vendor-specific operations used on this silicon version
  76  * @clockwatch: if this is an ST Microelectronics silicon version with a
  77  *      clockwatch function
  78  * @st_weekday: if this is an ST Microelectronics silicon version that need
  79  *      the weekday fix
  80  * @irqflags: special IRQ flags per variant
  81  */
  82 struct pl031_vendor_data {
  83         struct rtc_class_ops ops;
  84         bool clockwatch;
  85         bool st_weekday;
  86         unsigned long irqflags;
  87 };
  88
  89 struct pl031_local {
  90         struct pl031_vendor_data *vendor;
  91         struct rtc_device *rtc;
  92         void __iomem *base;
  93 };
  94
  95 static int pl031_alarm_irq_enable(struct device *dev,
  96         unsigned int enabled)
  97 {
  98         struct pl031_local *ldata = dev_get_drvdata(dev);
  99         unsigned long imsc;
 100
 101         /* Clear any pending alarm interrupts. */
 102         writel(RTC_BIT_AI, ldata->base + RTC_ICR);
 103
 104         imsc = readl(ldata->base + RTC_IMSC);
 105
 106         if (enabled == 1)
 107                 writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
 108         else
 109                 writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
 110
 111         return 0;
 112 }
 113
 114 /*
 115  * Convert Gregorian date to ST v2 RTC format.
 116  */
 117 static int pl031_stv2_tm_to_time(struct device *dev,
 118                                  struct rtc_time *tm, unsigned long *st_time,
 119         unsigned long *bcd_year)
 120 {
 121         int year = tm->tm_year + 1900;
 122         int wday = tm->tm_wday;
 123
 124         /* wday masking is not working in hardware so wday must be valid */
 125         if (wday < -1 || wday > 6) {
 126                 dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
 127                 return -EINVAL;
 128         } else if (wday == -1) {
 129                 /* wday is not provided, calculate it here */
 130                 unsigned long time;
 131                 struct rtc_time calc_tm;
 132
 133                 rtc_tm_to_time(tm, &time);
 134                 rtc_time_to_tm(time, &calc_tm);
 135                 wday = calc_tm.tm_wday;
 136         }
 137
 138         *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
 139
 140         *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
 141                         |       (tm->tm_mday << RTC_MDAY_SHIFT)
 142                         |       ((wday + 1) << RTC_WDAY_SHIFT)
 143                         |       (tm->tm_hour << RTC_HOUR_SHIFT)
 144                         |       (tm->tm_min << RTC_MIN_SHIFT)
 145                         |       (tm->tm_sec << RTC_SEC_SHIFT);
 146
 147         return 0;
 148 }
 149
 150 /*
 151  * Convert ST v2 RTC format to Gregorian date.
 152  */
 153 static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
 154         struct rtc_time *tm)
 155 {
 156         tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
 157         tm->tm_mon  = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
 158         tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
 159         tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
 160         tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
 161         tm->tm_min  = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
 162         tm->tm_sec  = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
 163
 164         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 165         tm->tm_year -= 1900;
 166
 167         return 0;
 168 }
 169
 170 static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
 171 {
 172         struct pl031_local *ldata = dev_get_drvdata(dev);
 173
 174         pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
 175                         readl(ldata->base + RTC_YDR), tm);
 176
 177         return 0;
 178 }
 179
 180 static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
 181 {
 182         unsigned long time;
 183         unsigned long bcd_year;
 184         struct pl031_local *ldata = dev_get_drvdata(dev);
 185         int ret;
 186
 187         ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
 188         if (ret == 0) {
 189                 writel(bcd_year, ldata->base + RTC_YLR);
 190                 writel(time, ldata->base + RTC_LR);
 191         }
 192
 193         return ret;
 194 }
 195
 196 static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 197 {
 198         struct pl031_local *ldata = dev_get_drvdata(dev);
 199         int ret;
 200
 201         ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
 202                         readl(ldata->base + RTC_YMR), &alarm->time);
 203
 204         alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
 205         alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
 206
 207         return ret;
 208 }
 209
 210 static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 211 {
 212         struct pl031_local *ldata = dev_get_drvdata(dev);
 213         unsigned long time;
 214         unsigned long bcd_year;
 215         int ret;
 216
 217         /* At the moment, we can only deal with non-wildcarded alarm times. */
 218         ret = rtc_valid_tm(&alarm->time);
 219         if (ret == 0) {
 220                 ret = pl031_stv2_tm_to_time(dev, &alarm->time,
 221                                             &time, &bcd_year);
 222                 if (ret == 0) {
 223                         writel(bcd_year, ldata->base + RTC_YMR);
 224                         writel(time, ldata->base + RTC_MR);
 225
 226                         pl031_alarm_irq_enable(dev, alarm->enabled);
 227                 }
 228         }
 229
 230         return ret;
 231 }
 232
 233 static irqreturn_t pl031_interrupt(int irq, void *dev_id)
 234 {
 235         struct pl031_local *ldata = dev_id;
 236         unsigned long rtcmis;
 237         unsigned long events = 0;
 238
 239         rtcmis = readl(ldata->base + RTC_MIS);
 240         if (rtcmis & RTC_BIT_AI) {
 241                 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
 242                 events |= (RTC_AF | RTC_IRQF);
 243                 rtc_update_irq(ldata->rtc, 1, events);
 244
 245                 return IRQ_HANDLED;
 246         }
 247
 248         return IRQ_NONE;
 249 }
 250
 251 static int pl031_read_time(struct device *dev, struct rtc_time *tm)
 252 {
 253         struct pl031_local *ldata = dev_get_drvdata(dev);
 254
 255         rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
 256
 257         return 0;
 258 }
 259
 260 static int pl031_set_time(struct device *dev, struct rtc_time *tm)
 261 {
 262         unsigned long time;
 263         struct pl031_local *ldata = dev_get_drvdata(dev);
 264         int ret;
 265
 266         ret = rtc_tm_to_time(tm, &time);
 267
 268         if (ret == 0)
 269                 writel(time, ldata->base + RTC_LR);
 270
 271         return ret;
 272 }
 273
 274 static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 275 {
 276         struct pl031_local *ldata = dev_get_drvdata(dev);
 277
 278         rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
 279
 280         alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
 281         alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
 282
 283         return 0;
 284 }
 285
 286 static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 287 {
 288         struct pl031_local *ldata = dev_get_drvdata(dev);
 289         unsigned long time;
 290         int ret;
 291
 292         /* At the moment, we can only deal with non-wildcarded alarm times. */
 293         ret = rtc_valid_tm(&alarm->time);
 294         if (ret == 0) {
 295                 ret = rtc_tm_to_time(&alarm->time, &time);
 296                 if (ret == 0) {
 297                         writel(time, ldata->base + RTC_MR);
 298                         pl031_alarm_irq_enable(dev, alarm->enabled);
 299                 }
 300         }
 301
 302         return ret;
 303 }
 304
 305 static int pl031_remove(struct amba_device *adev)
 306 {
 307         struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
 308
 309         dev_pm_clear_wake_irq(&adev->dev);
 310         device_init_wakeup(&adev->dev, false);
 311         if (adev->irq[0])
 312                 free_irq(adev->irq[0], ldata);
 313         rtc_device_unregister(ldata->rtc);
 314         amba_release_regions(adev);
 315
 316         return 0;
 317 }
 318
 319 static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
 320 {
 321         int ret;
 322         struct pl031_local *ldata;
 323         struct pl031_vendor_data *vendor = id->data;
 324         struct rtc_class_ops *ops;
 325         unsigned long time, data;
 326
 327         ret = amba_request_regions(adev, NULL);
 328         if (ret)
 329                 goto err_req;
 330
 331         ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local),
 332                              GFP_KERNEL);
 333         ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops),
 334                            GFP_KERNEL);
 335         if (!ldata || !ops) {
 336                 ret = -ENOMEM;
 337                 goto out;
 338         }
 339
 340         ldata->vendor = vendor;
 341         ldata->base = devm_ioremap(&adev->dev, adev->res.start,
 342                                    resource_size(&adev->res));
 343         if (!ldata->base) {
 344                 ret = -ENOMEM;
 345                 goto out;
 346         }
 347
 348         amba_set_drvdata(adev, ldata);
 349
 350         dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
 351         dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
 352
 353         data = readl(ldata->base + RTC_CR);
 354         /* Enable the clockwatch on ST Variants */
 355         if (vendor->clockwatch)
 356                 data |= RTC_CR_CWEN;
 357         else
 358                 data |= RTC_CR_EN;
 359         writel(data, ldata->base + RTC_CR);
 360
 361         /*
 362          * On ST PL031 variants, the RTC reset value does not provide correct
 363          * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
 364          */
 365         if (vendor->st_weekday) {
 366                 if (readl(ldata->base + RTC_YDR) == 0x2000) {
 367                         time = readl(ldata->base + RTC_DR);
 368                         if ((time &
 369                              (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
 370                             == 0x02120000) {
 371                                 time = time | (0x7 << RTC_WDAY_SHIFT);
 372                                 writel(0x2000, ldata->base + RTC_YLR);
 373                                 writel(time, ldata->base + RTC_LR);
 374                         }
 375                 }
 376         }
 377
 378         if (!adev->irq[0]) {
 379                 /* When there's no interrupt, no point in exposing the alarm */
 380                 ops->read_alarm = NULL;
 381                 ops->set_alarm = NULL;
 382                 ops->alarm_irq_enable = NULL;
 383         }
 384
 385         device_init_wakeup(&adev->dev, true);
 386         ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
 387                                         THIS_MODULE);
 388         if (IS_ERR(ldata->rtc)) {
 389                 ret = PTR_ERR(ldata->rtc);
 390                 goto out;
 391         }
 392
 393         if (adev->irq[0]) {
 394                 ret = request_irq(adev->irq[0], pl031_interrupt,
 395                                   vendor->irqflags, "rtc-pl031", ldata);
 396                 if (ret)
 397                         goto out_no_irq;
 398                 dev_pm_set_wake_irq(&adev->dev, adev->irq[0]);
 399         }
 400         return 0;
 401
 402 out_no_irq:
 403         rtc_device_unregister(ldata->rtc);
 404 out:
 405         amba_release_regions(adev);
 406 err_req:
 407
 408         return ret;
 409 }
 410
 411 /* Operations for the original ARM version */
 412 static struct pl031_vendor_data arm_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 };
 421
 422 /* The First ST derivative */
 423 static struct pl031_vendor_data stv1_pl031 = {
 424         .ops = {
 425                 .read_time = pl031_read_time,
 426                 .set_time = pl031_set_time,
 427                 .read_alarm = pl031_read_alarm,
 428                 .set_alarm = pl031_set_alarm,
 429                 .alarm_irq_enable = pl031_alarm_irq_enable,
 430         },
 431         .clockwatch = true,
 432         .st_weekday = true,
 433 };
 434
 435 /* And the second ST derivative */
 436 static struct pl031_vendor_data stv2_pl031 = {
 437         .ops = {
 438                 .read_time = pl031_stv2_read_time,
 439                 .set_time = pl031_stv2_set_time,
 440                 .read_alarm = pl031_stv2_read_alarm,
 441                 .set_alarm = pl031_stv2_set_alarm,
 442                 .alarm_irq_enable = pl031_alarm_irq_enable,
 443         },
 444         .clockwatch = true,
 445         .st_weekday = true,
 446         /*
 447          * This variant shares the IRQ with another block and must not
 448          * suspend that IRQ line.
 449          * TODO check if it shares with IRQF_NO_SUSPEND user, else we can
 450          * remove IRQF_COND_SUSPEND
 451          */
 452         .irqflags = IRQF_SHARED | IRQF_COND_SUSPEND,
 453 };
 454
 455 static const struct amba_id pl031_ids[] = {
 456         {
 457                 .id = 0x00041031,
 458                 .mask = 0x000fffff,
 459                 .data = &arm_pl031,
 460         },
 461         /* ST Micro variants */
 462         {
 463                 .id = 0x00180031,
 464                 .mask = 0x00ffffff,
 465                 .data = &stv1_pl031,
 466         },
 467         {
 468                 .id = 0x00280031,
 469                 .mask = 0x00ffffff,
 470                 .data = &stv2_pl031,
 471         },
 472         {0, 0},
 473 };
 474
 475 MODULE_DEVICE_TABLE(amba, pl031_ids);
 476
 477 static struct amba_driver pl031_driver = {
 478         .drv = {
 479                 .name = "rtc-pl031",
 480         },
 481         .id_table = pl031_ids,
 482         .probe = pl031_probe,
 483         .remove = pl031_remove,
 484 };
 485
 486 module_amba_driver(pl031_driver);
 487
 488 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
 489 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
 490 MODULE_LICENSE("GPL");