linux/drivers/rtc/rtc-pl031.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * drivers/rtc/rtc-pl031.c
   4 *
   5 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
   6 *
   7 * Author: Deepak Saxena <dsaxena@plexity.net>
   8 *
   9 * Copyright 2006 (c) MontaVista Software, Inc.
  10 *
  11 * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
  12 * Copyright 2010 (c) ST-Ericsson AB
  13 */
  14#include <linux/module.h>
  15#include <linux/rtc.h>
  16#include <linux/init.h>
  17#include <linux/interrupt.h>
  18#include <linux/amba/bus.h>
  19#include <linux/io.h>
  20#include <linux/bcd.h>
  21#include <linux/delay.h>
  22#include <linux/pm_wakeirq.h>
  23#include <linux/slab.h>
  24
  25/*
  26 * Register definitions
  27 */
  28#define RTC_DR          0x00    /* Data read register */
  29#define RTC_MR          0x04    /* Match register */
  30#define RTC_LR          0x08    /* Data load register */
  31#define RTC_CR          0x0c    /* Control register */
  32#define RTC_IMSC        0x10    /* Interrupt mask and set register */
  33#define RTC_RIS         0x14    /* Raw interrupt status register */
  34#define RTC_MIS         0x18    /* Masked interrupt status register */
  35#define RTC_ICR         0x1c    /* Interrupt clear register */
  36/* ST variants have additional timer functionality */
  37#define RTC_TDR         0x20    /* Timer data read register */
  38#define RTC_TLR         0x24    /* Timer data load register */
  39#define RTC_TCR         0x28    /* Timer control register */
  40#define RTC_YDR         0x30    /* Year data read register */
  41#define RTC_YMR         0x34    /* Year match register */
  42#define RTC_YLR         0x38    /* Year data load register */
  43
  44#define RTC_CR_EN       (1 << 0)        /* counter enable bit */
  45#define RTC_CR_CWEN     (1 << 26)       /* Clockwatch enable bit */
  46
  47#define RTC_TCR_EN      (1 << 1) /* Periodic timer enable bit */
  48
  49/* Common bit definitions for Interrupt status and control registers */
  50#define RTC_BIT_AI      (1 << 0) /* Alarm interrupt bit */
  51#define RTC_BIT_PI      (1 << 1) /* Periodic interrupt bit. ST variants only. */
  52
  53/* Common bit definations for ST v2 for reading/writing time */
  54#define RTC_SEC_SHIFT 0
  55#define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
  56#define RTC_MIN_SHIFT 6
  57#define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
  58#define RTC_HOUR_SHIFT 12
  59#define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
  60#define RTC_WDAY_SHIFT 17
  61#define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
  62#define RTC_MDAY_SHIFT 20
  63#define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
  64#define RTC_MON_SHIFT 25
  65#define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
  66
  67#define RTC_TIMER_FREQ 32768
  68
  69/**
  70 * struct pl031_vendor_data - per-vendor variations
  71 * @ops: the vendor-specific operations used on this silicon version
  72 * @clockwatch: if this is an ST Microelectronics silicon version with a
  73 *      clockwatch function
  74 * @st_weekday: if this is an ST Microelectronics silicon version that need
  75 *      the weekday fix
  76 * @irqflags: special IRQ flags per variant
  77 */
  78struct pl031_vendor_data {
  79        struct rtc_class_ops ops;
  80        bool clockwatch;
  81        bool st_weekday;
  82        unsigned long irqflags;
  83        time64_t range_min;
  84        timeu64_t range_max;
  85};
  86
  87struct pl031_local {
  88        struct pl031_vendor_data *vendor;
  89        struct rtc_device *rtc;
  90        void __iomem *base;
  91};
  92
  93static 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 */
 115static 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                struct rtc_time calc_tm;
 129
 130                rtc_time64_to_tm(rtc_tm_to_time64(tm), &calc_tm);
 131                wday = calc_tm.tm_wday;
 132        }
 133
 134        *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
 135
 136        *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
 137                        |       (tm->tm_mday << RTC_MDAY_SHIFT)
 138                        |       ((wday + 1) << RTC_WDAY_SHIFT)
 139                        |       (tm->tm_hour << RTC_HOUR_SHIFT)
 140                        |       (tm->tm_min << RTC_MIN_SHIFT)
 141                        |       (tm->tm_sec << RTC_SEC_SHIFT);
 142
 143        return 0;
 144}
 145
 146/*
 147 * Convert ST v2 RTC format to Gregorian date.
 148 */
 149static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
 150        struct rtc_time *tm)
 151{
 152        tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
 153        tm->tm_mon  = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
 154        tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
 155        tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
 156        tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
 157        tm->tm_min  = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
 158        tm->tm_sec  = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
 159
 160        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 161        tm->tm_year -= 1900;
 162
 163        return 0;
 164}
 165
 166static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
 167{
 168        struct pl031_local *ldata = dev_get_drvdata(dev);
 169
 170        pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
 171                        readl(ldata->base + RTC_YDR), tm);
 172
 173        return 0;
 174}
 175
 176static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
 177{
 178        unsigned long time;
 179        unsigned long bcd_year;
 180        struct pl031_local *ldata = dev_get_drvdata(dev);
 181        int ret;
 182
 183        ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
 184        if (ret == 0) {
 185                writel(bcd_year, ldata->base + RTC_YLR);
 186                writel(time, ldata->base + RTC_LR);
 187        }
 188
 189        return ret;
 190}
 191
 192static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 193{
 194        struct pl031_local *ldata = dev_get_drvdata(dev);
 195        int ret;
 196
 197        ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
 198                        readl(ldata->base + RTC_YMR), &alarm->time);
 199
 200        alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
 201        alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
 202
 203        return ret;
 204}
 205
 206static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 207{
 208        struct pl031_local *ldata = dev_get_drvdata(dev);
 209        unsigned long time;
 210        unsigned long bcd_year;
 211        int ret;
 212
 213        ret = pl031_stv2_tm_to_time(dev, &alarm->time,
 214                                    &time, &bcd_year);
 215        if (ret == 0) {
 216                writel(bcd_year, ldata->base + RTC_YMR);
 217                writel(time, ldata->base + RTC_MR);
 218
 219                pl031_alarm_irq_enable(dev, alarm->enabled);
 220        }
 221
 222        return ret;
 223}
 224
 225static irqreturn_t pl031_interrupt(int irq, void *dev_id)
 226{
 227        struct pl031_local *ldata = dev_id;
 228        unsigned long rtcmis;
 229        unsigned long events = 0;
 230
 231        rtcmis = readl(ldata->base + RTC_MIS);
 232        if (rtcmis & RTC_BIT_AI) {
 233                writel(RTC_BIT_AI, ldata->base + RTC_ICR);
 234                events |= (RTC_AF | RTC_IRQF);
 235                rtc_update_irq(ldata->rtc, 1, events);
 236
 237                return IRQ_HANDLED;
 238        }
 239
 240        return IRQ_NONE;
 241}
 242
 243static int pl031_read_time(struct device *dev, struct rtc_time *tm)
 244{
 245        struct pl031_local *ldata = dev_get_drvdata(dev);
 246
 247        rtc_time64_to_tm(readl(ldata->base + RTC_DR), tm);
 248
 249        return 0;
 250}
 251
 252static int pl031_set_time(struct device *dev, struct rtc_time *tm)
 253{
 254        struct pl031_local *ldata = dev_get_drvdata(dev);
 255
 256        writel(rtc_tm_to_time64(tm), ldata->base + RTC_LR);
 257
 258        return 0;
 259}
 260
 261static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 262{
 263        struct pl031_local *ldata = dev_get_drvdata(dev);
 264
 265        rtc_time64_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
 266
 267        alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
 268        alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
 269
 270        return 0;
 271}
 272
 273static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 274{
 275        struct pl031_local *ldata = dev_get_drvdata(dev);
 276
 277        writel(rtc_tm_to_time64(&alarm->time), ldata->base + RTC_MR);
 278        pl031_alarm_irq_enable(dev, alarm->enabled);
 279
 280        return 0;
 281}
 282
 283static void pl031_remove(struct amba_device *adev)
 284{
 285        struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
 286
 287        dev_pm_clear_wake_irq(&adev->dev);
 288        device_init_wakeup(&adev->dev, false);
 289        if (adev->irq[0])
 290                free_irq(adev->irq[0], ldata);
 291        amba_release_regions(adev);
 292}
 293
 294static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
 295{
 296        int ret;
 297        struct pl031_local *ldata;
 298        struct pl031_vendor_data *vendor = id->data;
 299        struct rtc_class_ops *ops;
 300        unsigned long time, data;
 301
 302        ret = amba_request_regions(adev, NULL);
 303        if (ret)
 304                goto err_req;
 305
 306        ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local),
 307                             GFP_KERNEL);
 308        ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops),
 309                           GFP_KERNEL);
 310        if (!ldata || !ops) {
 311                ret = -ENOMEM;
 312                goto out;
 313        }
 314
 315        ldata->vendor = vendor;
 316        ldata->base = devm_ioremap(&adev->dev, adev->res.start,
 317                                   resource_size(&adev->res));
 318        if (!ldata->base) {
 319                ret = -ENOMEM;
 320                goto out;
 321        }
 322
 323        amba_set_drvdata(adev, ldata);
 324
 325        dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
 326        dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
 327
 328        data = readl(ldata->base + RTC_CR);
 329        /* Enable the clockwatch on ST Variants */
 330        if (vendor->clockwatch)
 331                data |= RTC_CR_CWEN;
 332        else
 333                data |= RTC_CR_EN;
 334        writel(data, ldata->base + RTC_CR);
 335
 336        /*
 337         * On ST PL031 variants, the RTC reset value does not provide correct
 338         * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
 339         */
 340        if (vendor->st_weekday) {
 341                if (readl(ldata->base + RTC_YDR) == 0x2000) {
 342                        time = readl(ldata->base + RTC_DR);
 343                        if ((time &
 344                             (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
 345                            == 0x02120000) {
 346                                time = time | (0x7 << RTC_WDAY_SHIFT);
 347                                writel(0x2000, ldata->base + RTC_YLR);
 348                                writel(time, ldata->base + RTC_LR);
 349                        }
 350                }
 351        }
 352
 353        if (!adev->irq[0])
 354                clear_bit(RTC_FEATURE_ALARM, ldata->rtc->features);
 355
 356        device_init_wakeup(&adev->dev, true);
 357        ldata->rtc = devm_rtc_allocate_device(&adev->dev);
 358        if (IS_ERR(ldata->rtc)) {
 359                ret = PTR_ERR(ldata->rtc);
 360                goto out;
 361        }
 362
 363        ldata->rtc->ops = ops;
 364        ldata->rtc->range_min = vendor->range_min;
 365        ldata->rtc->range_max = vendor->range_max;
 366
 367        ret = devm_rtc_register_device(ldata->rtc);
 368        if (ret)
 369                goto out;
 370
 371        if (adev->irq[0]) {
 372                ret = request_irq(adev->irq[0], pl031_interrupt,
 373                                  vendor->irqflags, "rtc-pl031", ldata);
 374                if (ret)
 375                        goto out;
 376                dev_pm_set_wake_irq(&adev->dev, adev->irq[0]);
 377        }
 378        return 0;
 379
 380out:
 381        amba_release_regions(adev);
 382err_req:
 383
 384        return ret;
 385}
 386
 387/* Operations for the original ARM version */
 388static struct pl031_vendor_data arm_pl031 = {
 389        .ops = {
 390                .read_time = pl031_read_time,
 391                .set_time = pl031_set_time,
 392                .read_alarm = pl031_read_alarm,
 393                .set_alarm = pl031_set_alarm,
 394                .alarm_irq_enable = pl031_alarm_irq_enable,
 395        },
 396        .range_max = U32_MAX,
 397};
 398
 399/* The First ST derivative */
 400static struct pl031_vendor_data stv1_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        .clockwatch = true,
 409        .st_weekday = true,
 410        .range_max = U32_MAX,
 411};
 412
 413/* And the second ST derivative */
 414static struct pl031_vendor_data stv2_pl031 = {
 415        .ops = {
 416                .read_time = pl031_stv2_read_time,
 417                .set_time = pl031_stv2_set_time,
 418                .read_alarm = pl031_stv2_read_alarm,
 419                .set_alarm = pl031_stv2_set_alarm,
 420                .alarm_irq_enable = pl031_alarm_irq_enable,
 421        },
 422        .clockwatch = true,
 423        .st_weekday = true,
 424        /*
 425         * This variant shares the IRQ with another block and must not
 426         * suspend that IRQ line.
 427         * TODO check if it shares with IRQF_NO_SUSPEND user, else we can
 428         * remove IRQF_COND_SUSPEND
 429         */
 430        .irqflags = IRQF_SHARED | IRQF_COND_SUSPEND,
 431        .range_min = RTC_TIMESTAMP_BEGIN_0000,
 432        .range_max = RTC_TIMESTAMP_END_9999,
 433};
 434
 435static const struct amba_id pl031_ids[] = {
 436        {
 437                .id = 0x00041031,
 438                .mask = 0x000fffff,
 439                .data = &arm_pl031,
 440        },
 441        /* ST Micro variants */
 442        {
 443                .id = 0x00180031,
 444                .mask = 0x00ffffff,
 445                .data = &stv1_pl031,
 446        },
 447        {
 448                .id = 0x00280031,
 449                .mask = 0x00ffffff,
 450                .data = &stv2_pl031,
 451        },
 452        {0, 0},
 453};
 454
 455MODULE_DEVICE_TABLE(amba, pl031_ids);
 456
 457static struct amba_driver pl031_driver = {
 458        .drv = {
 459                .name = "rtc-pl031",
 460        },
 461        .id_table = pl031_ids,
 462        .probe = pl031_probe,
 463        .remove = pl031_remove,
 464};
 465
 466module_amba_driver(pl031_driver);
 467
 468MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
 469MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
 470MODULE_LICENSE("GPL");
 471