drivers/rtc/rtc-pl031.c

   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  */
  78 struct 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
  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                 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  */
 149 static 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
 166 static 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
 176 static 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
 192 static 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
 206 static 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
 225 static 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
 243 static 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
 252 static 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
 261 static 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
 273 static 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
 283 static int 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         return 0;
 294 }
 295
 296 static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
 297 {
 298         int ret;
 299         struct pl031_local *ldata;
 300         struct pl031_vendor_data *vendor = id->data;
 301         struct rtc_class_ops *ops;
 302         unsigned long time, data;
 303
 304         ret = amba_request_regions(adev, NULL);
 305         if (ret)
 306                 goto err_req;
 307
 308         ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local),
 309                              GFP_KERNEL);
 310         ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops),
 311                            GFP_KERNEL);
 312         if (!ldata || !ops) {
 313                 ret = -ENOMEM;
 314                 goto out;
 315         }
 316
 317         ldata->vendor = vendor;
 318         ldata->base = devm_ioremap(&adev->dev, adev->res.start,
 319                                    resource_size(&adev->res));
 320         if (!ldata->base) {
 321                 ret = -ENOMEM;
 322                 goto out;
 323         }
 324
 325         amba_set_drvdata(adev, ldata);
 326
 327         dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
 328         dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
 329
 330         data = readl(ldata->base + RTC_CR);
 331         /* Enable the clockwatch on ST Variants */
 332         if (vendor->clockwatch)
 333                 data |= RTC_CR_CWEN;
 334         else
 335                 data |= RTC_CR_EN;
 336         writel(data, ldata->base + RTC_CR);
 337
 338         /*
 339          * On ST PL031 variants, the RTC reset value does not provide correct
 340          * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
 341          */
 342         if (vendor->st_weekday) {
 343                 if (readl(ldata->base + RTC_YDR) == 0x2000) {
 344                         time = readl(ldata->base + RTC_DR);
 345                         if ((time &
 346                              (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
 347                             == 0x02120000) {
 348                                 time = time | (0x7 << RTC_WDAY_SHIFT);
 349                                 writel(0x2000, ldata->base + RTC_YLR);
 350                                 writel(time, ldata->base + RTC_LR);
 351                         }
 352                 }
 353         }
 354
 355         if (!adev->irq[0]) {
 356                 /* When there's no interrupt, no point in exposing the alarm */
 357                 ops->read_alarm = NULL;
 358                 ops->set_alarm = NULL;
 359                 ops->alarm_irq_enable = NULL;
 360         }
 361
 362         device_init_wakeup(&adev->dev, true);
 363         ldata->rtc = devm_rtc_allocate_device(&adev->dev);
 364         if (IS_ERR(ldata->rtc)) {
 365                 ret = PTR_ERR(ldata->rtc);
 366                 goto out;
 367         }
 368
 369         ldata->rtc->ops = ops;
 370         ldata->rtc->range_min = vendor->range_min;
 371         ldata->rtc->range_max = vendor->range_max;
 372
 373         ret = devm_rtc_register_device(ldata->rtc);
 374         if (ret)
 375                 goto out;
 376
 377         if (adev->irq[0]) {
 378                 ret = request_irq(adev->irq[0], pl031_interrupt,
 379                                   vendor->irqflags, "rtc-pl031", ldata);
 380                 if (ret)
 381                         goto out;
 382                 dev_pm_set_wake_irq(&adev->dev, adev->irq[0]);
 383         }
 384         return 0;
 385
 386 out:
 387         amba_release_regions(adev);
 388 err_req:
 389
 390         return ret;
 391 }
 392
 393 /* Operations for the original ARM version */
 394 static struct pl031_vendor_data arm_pl031 = {
 395         .ops = {
 396                 .read_time = pl031_read_time,
 397                 .set_time = pl031_set_time,
 398                 .read_alarm = pl031_read_alarm,
 399                 .set_alarm = pl031_set_alarm,
 400                 .alarm_irq_enable = pl031_alarm_irq_enable,
 401         },
 402         .range_max = U32_MAX,
 403 };
 404
 405 /* The First ST derivative */
 406 static struct pl031_vendor_data stv1_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         .clockwatch = true,
 415         .st_weekday = true,
 416         .range_max = U32_MAX,
 417 };
 418
 419 /* And the second ST derivative */
 420 static struct pl031_vendor_data stv2_pl031 = {
 421         .ops = {
 422                 .read_time = pl031_stv2_read_time,
 423                 .set_time = pl031_stv2_set_time,
 424                 .read_alarm = pl031_stv2_read_alarm,
 425                 .set_alarm = pl031_stv2_set_alarm,
 426                 .alarm_irq_enable = pl031_alarm_irq_enable,
 427         },
 428         .clockwatch = true,
 429         .st_weekday = true,
 430         /*
 431          * This variant shares the IRQ with another block and must not
 432          * suspend that IRQ line.
 433          * TODO check if it shares with IRQF_NO_SUSPEND user, else we can
 434          * remove IRQF_COND_SUSPEND
 435          */
 436         .irqflags = IRQF_SHARED | IRQF_COND_SUSPEND,
 437         .range_min = RTC_TIMESTAMP_BEGIN_0000,
 438         .range_max = RTC_TIMESTAMP_END_9999,
 439 };
 440
 441 static const struct amba_id pl031_ids[] = {
 442         {
 443                 .id = 0x00041031,
 444                 .mask = 0x000fffff,
 445                 .data = &arm_pl031,
 446         },
 447         /* ST Micro variants */
 448         {
 449                 .id = 0x00180031,
 450                 .mask = 0x00ffffff,
 451                 .data = &stv1_pl031,
 452         },
 453         {
 454                 .id = 0x00280031,
 455                 .mask = 0x00ffffff,
 456                 .data = &stv2_pl031,
 457         },
 458         {0, 0},
 459 };
 460
 461 MODULE_DEVICE_TABLE(amba, pl031_ids);
 462
 463 static struct amba_driver pl031_driver = {
 464         .drv = {
 465                 .name = "rtc-pl031",
 466         },
 467         .id_table = pl031_ids,
 468         .probe = pl031_probe,
 469         .remove = pl031_remove,
 470 };
 471
 472 module_amba_driver(pl031_driver);
 473
 474 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
 475 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
 476 MODULE_LICENSE("GPL");