linux/drivers/rtc/rtc-pl031.c
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   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 */
  81struct pl031_vendor_data {
  82        struct rtc_class_ops ops;
  83        bool clockwatch;
  84        bool st_weekday;
  85        unsigned long irqflags;
  86};
  87
  88struct pl031_local {
  89        struct pl031_vendor_data *vendor;
  90        struct rtc_device *rtc;
  91        void __iomem *base;
  92};
  93
  94static 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 */
 116static 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 */
 152static 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
 169static 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
 179static 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
 195static 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
 209static 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
 232static 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
 250static 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
 259static 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
 273static 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
 285static 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
 304static 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
 318static 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
 391out_no_irq:
 392        rtc_device_unregister(ldata->rtc);
 393out_no_rtc:
 394        iounmap(ldata->base);
 395        amba_set_drvdata(adev, NULL);
 396out_no_remap:
 397        kfree(ldata);
 398out:
 399        amba_release_regions(adev);
 400err_req:
 401
 402        return ret;
 403}
 404
 405/* Operations for the original ARM version */
 406static 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 */
 418static 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 */
 432static 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
 449static 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
 469MODULE_DEVICE_TABLE(amba, pl031_ids);
 470
 471static 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
 480module_amba_driver(pl031_driver);
 481
 482MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
 483MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
 484MODULE_LICENSE("GPL");
 485
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