drivers/rtc/rtc-sunxi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * An RTC driver for Allwinner A10/A20
   4  *
   5  * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
   6  */
   7
   8 #include <linux/delay.h>
   9 #include <linux/err.h>
  10 #include <linux/fs.h>
  11 #include <linux/init.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/io.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_device.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/rtc.h>
  21 #include <linux/types.h>
  22
  23 #define SUNXI_LOSC_CTRL                         0x0000
  24 #define SUNXI_LOSC_CTRL_RTC_HMS_ACC             BIT(8)
  25 #define SUNXI_LOSC_CTRL_RTC_YMD_ACC             BIT(7)
  26
  27 #define SUNXI_RTC_YMD                           0x0004
  28
  29 #define SUNXI_RTC_HMS                           0x0008
  30
  31 #define SUNXI_ALRM_DHMS                         0x000c
  32
  33 #define SUNXI_ALRM_EN                           0x0014
  34 #define SUNXI_ALRM_EN_CNT_EN                    BIT(8)
  35
  36 #define SUNXI_ALRM_IRQ_EN                       0x0018
  37 #define SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN            BIT(0)
  38
  39 #define SUNXI_ALRM_IRQ_STA                      0x001c
  40 #define SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND         BIT(0)
  41
  42 #define SUNXI_MASK_DH                           0x0000001f
  43 #define SUNXI_MASK_SM                           0x0000003f
  44 #define SUNXI_MASK_M                            0x0000000f
  45 #define SUNXI_MASK_LY                           0x00000001
  46 #define SUNXI_MASK_D                            0x00000ffe
  47 #define SUNXI_MASK_M                            0x0000000f
  48
  49 #define SUNXI_GET(x, mask, shift)               (((x) & ((mask) << (shift))) \
  50                                                         >> (shift))
  51
  52 #define SUNXI_SET(x, mask, shift)               (((x) & (mask)) << (shift))
  53
  54 /*
  55  * Get date values
  56  */
  57 #define SUNXI_DATE_GET_DAY_VALUE(x)             SUNXI_GET(x, SUNXI_MASK_DH, 0)
  58 #define SUNXI_DATE_GET_MON_VALUE(x)             SUNXI_GET(x, SUNXI_MASK_M, 8)
  59 #define SUNXI_DATE_GET_YEAR_VALUE(x, mask)      SUNXI_GET(x, mask, 16)
  60
  61 /*
  62  * Get time values
  63  */
  64 #define SUNXI_TIME_GET_SEC_VALUE(x)             SUNXI_GET(x, SUNXI_MASK_SM, 0)
  65 #define SUNXI_TIME_GET_MIN_VALUE(x)             SUNXI_GET(x, SUNXI_MASK_SM, 8)
  66 #define SUNXI_TIME_GET_HOUR_VALUE(x)            SUNXI_GET(x, SUNXI_MASK_DH, 16)
  67
  68 /*
  69  * Get alarm values
  70  */
  71 #define SUNXI_ALRM_GET_SEC_VALUE(x)             SUNXI_GET(x, SUNXI_MASK_SM, 0)
  72 #define SUNXI_ALRM_GET_MIN_VALUE(x)             SUNXI_GET(x, SUNXI_MASK_SM, 8)
  73 #define SUNXI_ALRM_GET_HOUR_VALUE(x)            SUNXI_GET(x, SUNXI_MASK_DH, 16)
  74
  75 /*
  76  * Set date values
  77  */
  78 #define SUNXI_DATE_SET_DAY_VALUE(x)             SUNXI_DATE_GET_DAY_VALUE(x)
  79 #define SUNXI_DATE_SET_MON_VALUE(x)             SUNXI_SET(x, SUNXI_MASK_M, 8)
  80 #define SUNXI_DATE_SET_YEAR_VALUE(x, mask)      SUNXI_SET(x, mask, 16)
  81 #define SUNXI_LEAP_SET_VALUE(x, shift)          SUNXI_SET(x, SUNXI_MASK_LY, shift)
  82
  83 /*
  84  * Set time values
  85  */
  86 #define SUNXI_TIME_SET_SEC_VALUE(x)             SUNXI_TIME_GET_SEC_VALUE(x)
  87 #define SUNXI_TIME_SET_MIN_VALUE(x)             SUNXI_SET(x, SUNXI_MASK_SM, 8)
  88 #define SUNXI_TIME_SET_HOUR_VALUE(x)            SUNXI_SET(x, SUNXI_MASK_DH, 16)
  89
  90 /*
  91  * Set alarm values
  92  */
  93 #define SUNXI_ALRM_SET_SEC_VALUE(x)             SUNXI_ALRM_GET_SEC_VALUE(x)
  94 #define SUNXI_ALRM_SET_MIN_VALUE(x)             SUNXI_SET(x, SUNXI_MASK_SM, 8)
  95 #define SUNXI_ALRM_SET_HOUR_VALUE(x)            SUNXI_SET(x, SUNXI_MASK_DH, 16)
  96 #define SUNXI_ALRM_SET_DAY_VALUE(x)             SUNXI_SET(x, SUNXI_MASK_D, 21)
  97
  98 /*
  99  * Time unit conversions
 100  */
 101 #define SEC_IN_MIN                              60
 102 #define SEC_IN_HOUR                             (60 * SEC_IN_MIN)
 103 #define SEC_IN_DAY                              (24 * SEC_IN_HOUR)
 104
 105 /*
 106  * The year parameter passed to the driver is usually an offset relative to
 107  * the year 1900. This macro is used to convert this offset to another one
 108  * relative to the minimum year allowed by the hardware.
 109  */
 110 #define SUNXI_YEAR_OFF(x)                       ((x)->min - 1900)
 111
 112 /*
 113  * min and max year are arbitrary set considering the limited range of the
 114  * hardware register field
 115  */
 116 struct sunxi_rtc_data_year {
 117         unsigned int min;               /* min year allowed */
 118         unsigned int max;               /* max year allowed */
 119         unsigned int mask;              /* mask for the year field */
 120         unsigned char leap_shift;       /* bit shift to get the leap year */
 121 };
 122
 123 static const struct sunxi_rtc_data_year data_year_param[] = {
 124         [0] = {
 125                 .min            = 2010,
 126                 .max            = 2073,
 127                 .mask           = 0x3f,
 128                 .leap_shift     = 22,
 129         },
 130         [1] = {
 131                 .min            = 1970,
 132                 .max            = 2225,
 133                 .mask           = 0xff,
 134                 .leap_shift     = 24,
 135         },
 136 };
 137
 138 struct sunxi_rtc_dev {
 139         struct rtc_device *rtc;
 140         struct device *dev;
 141         const struct sunxi_rtc_data_year *data_year;
 142         void __iomem *base;
 143         int irq;
 144 };
 145
 146 static irqreturn_t sunxi_rtc_alarmirq(int irq, void *id)
 147 {
 148         struct sunxi_rtc_dev *chip = (struct sunxi_rtc_dev *) id;
 149         u32 val;
 150
 151         val = readl(chip->base + SUNXI_ALRM_IRQ_STA);
 152
 153         if (val & SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND) {
 154                 val |= SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND;
 155                 writel(val, chip->base + SUNXI_ALRM_IRQ_STA);
 156
 157                 rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
 158
 159                 return IRQ_HANDLED;
 160         }
 161
 162         return IRQ_NONE;
 163 }
 164
 165 static void sunxi_rtc_setaie(unsigned int to, struct sunxi_rtc_dev *chip)
 166 {
 167         u32 alrm_val = 0;
 168         u32 alrm_irq_val = 0;
 169
 170         if (to) {
 171                 alrm_val = readl(chip->base + SUNXI_ALRM_EN);
 172                 alrm_val |= SUNXI_ALRM_EN_CNT_EN;
 173
 174                 alrm_irq_val = readl(chip->base + SUNXI_ALRM_IRQ_EN);
 175                 alrm_irq_val |= SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN;
 176         } else {
 177                 writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND,
 178                                 chip->base + SUNXI_ALRM_IRQ_STA);
 179         }
 180
 181         writel(alrm_val, chip->base + SUNXI_ALRM_EN);
 182         writel(alrm_irq_val, chip->base + SUNXI_ALRM_IRQ_EN);
 183 }
 184
 185 static int sunxi_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 186 {
 187         struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
 188         struct rtc_time *alrm_tm = &wkalrm->time;
 189         u32 alrm;
 190         u32 alrm_en;
 191         u32 date;
 192
 193         alrm = readl(chip->base + SUNXI_ALRM_DHMS);
 194         date = readl(chip->base + SUNXI_RTC_YMD);
 195
 196         alrm_tm->tm_sec = SUNXI_ALRM_GET_SEC_VALUE(alrm);
 197         alrm_tm->tm_min = SUNXI_ALRM_GET_MIN_VALUE(alrm);
 198         alrm_tm->tm_hour = SUNXI_ALRM_GET_HOUR_VALUE(alrm);
 199
 200         alrm_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
 201         alrm_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);
 202         alrm_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
 203                         chip->data_year->mask);
 204
 205         alrm_tm->tm_mon -= 1;
 206
 207         /*
 208          * switch from (data_year->min)-relative offset to
 209          * a (1900)-relative one
 210          */
 211         alrm_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);
 212
 213         alrm_en = readl(chip->base + SUNXI_ALRM_IRQ_EN);
 214         if (alrm_en & SUNXI_ALRM_EN_CNT_EN)
 215                 wkalrm->enabled = 1;
 216
 217         return 0;
 218 }
 219
 220 static int sunxi_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 221 {
 222         struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
 223         u32 date, time;
 224
 225         /*
 226          * read again in case it changes
 227          */
 228         do {
 229                 date = readl(chip->base + SUNXI_RTC_YMD);
 230                 time = readl(chip->base + SUNXI_RTC_HMS);
 231         } while ((date != readl(chip->base + SUNXI_RTC_YMD)) ||
 232                  (time != readl(chip->base + SUNXI_RTC_HMS)));
 233
 234         rtc_tm->tm_sec  = SUNXI_TIME_GET_SEC_VALUE(time);
 235         rtc_tm->tm_min  = SUNXI_TIME_GET_MIN_VALUE(time);
 236         rtc_tm->tm_hour = SUNXI_TIME_GET_HOUR_VALUE(time);
 237
 238         rtc_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
 239         rtc_tm->tm_mon  = SUNXI_DATE_GET_MON_VALUE(date);
 240         rtc_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
 241                                         chip->data_year->mask);
 242
 243         rtc_tm->tm_mon  -= 1;
 244
 245         /*
 246          * switch from (data_year->min)-relative offset to
 247          * a (1900)-relative one
 248          */
 249         rtc_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);
 250
 251         return 0;
 252 }
 253
 254 static int sunxi_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 255 {
 256         struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
 257         struct rtc_time *alrm_tm = &wkalrm->time;
 258         struct rtc_time tm_now;
 259         u32 alrm;
 260         time64_t diff;
 261         unsigned long time_gap;
 262         unsigned long time_gap_day;
 263         unsigned long time_gap_hour;
 264         unsigned long time_gap_min;
 265         int ret;
 266
 267         ret = sunxi_rtc_gettime(dev, &tm_now);
 268         if (ret < 0) {
 269                 dev_err(dev, "Error in getting time\n");
 270                 return -EINVAL;
 271         }
 272
 273         diff = rtc_tm_sub(alrm_tm, &tm_now);
 274         if (diff <= 0) {
 275                 dev_err(dev, "Date to set in the past\n");
 276                 return -EINVAL;
 277         }
 278
 279         if (diff > 255 * SEC_IN_DAY) {
 280                 dev_err(dev, "Day must be in the range 0 - 255\n");
 281                 return -EINVAL;
 282         }
 283
 284         time_gap = diff;
 285         time_gap_day = time_gap / SEC_IN_DAY;
 286         time_gap -= time_gap_day * SEC_IN_DAY;
 287         time_gap_hour = time_gap / SEC_IN_HOUR;
 288         time_gap -= time_gap_hour * SEC_IN_HOUR;
 289         time_gap_min = time_gap / SEC_IN_MIN;
 290         time_gap -= time_gap_min * SEC_IN_MIN;
 291
 292         sunxi_rtc_setaie(0, chip);
 293         writel(0, chip->base + SUNXI_ALRM_DHMS);
 294         usleep_range(100, 300);
 295
 296         alrm = SUNXI_ALRM_SET_SEC_VALUE(time_gap) |
 297                 SUNXI_ALRM_SET_MIN_VALUE(time_gap_min) |
 298                 SUNXI_ALRM_SET_HOUR_VALUE(time_gap_hour) |
 299                 SUNXI_ALRM_SET_DAY_VALUE(time_gap_day);
 300         writel(alrm, chip->base + SUNXI_ALRM_DHMS);
 301
 302         writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
 303         writel(SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN, chip->base + SUNXI_ALRM_IRQ_EN);
 304
 305         sunxi_rtc_setaie(wkalrm->enabled, chip);
 306
 307         return 0;
 308 }
 309
 310 static int sunxi_rtc_wait(struct sunxi_rtc_dev *chip, int offset,
 311                           unsigned int mask, unsigned int ms_timeout)
 312 {
 313         const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
 314         u32 reg;
 315
 316         do {
 317                 reg = readl(chip->base + offset);
 318                 reg &= mask;
 319
 320                 if (reg == mask)
 321                         return 0;
 322
 323         } while (time_before(jiffies, timeout));
 324
 325         return -ETIMEDOUT;
 326 }
 327
 328 static int sunxi_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
 329 {
 330         struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
 331         u32 date = 0;
 332         u32 time = 0;
 333         unsigned int year;
 334
 335         /*
 336          * the input rtc_tm->tm_year is the offset relative to 1900. We use
 337          * the SUNXI_YEAR_OFF macro to rebase it with respect to the min year
 338          * allowed by the hardware
 339          */
 340
 341         year = rtc_tm->tm_year + 1900;
 342         if (year < chip->data_year->min || year > chip->data_year->max) {
 343                 dev_err(dev, "rtc only supports year in range %u - %u\n",
 344                         chip->data_year->min, chip->data_year->max);
 345                 return -EINVAL;
 346         }
 347
 348         rtc_tm->tm_year -= SUNXI_YEAR_OFF(chip->data_year);
 349         rtc_tm->tm_mon += 1;
 350
 351         date = SUNXI_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
 352                 SUNXI_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
 353                 SUNXI_DATE_SET_YEAR_VALUE(rtc_tm->tm_year,
 354                                 chip->data_year->mask);
 355
 356         if (is_leap_year(year))
 357                 date |= SUNXI_LEAP_SET_VALUE(1, chip->data_year->leap_shift);
 358
 359         time = SUNXI_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
 360                 SUNXI_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
 361                 SUNXI_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
 362
 363         writel(0, chip->base + SUNXI_RTC_HMS);
 364         writel(0, chip->base + SUNXI_RTC_YMD);
 365
 366         writel(time, chip->base + SUNXI_RTC_HMS);
 367
 368         /*
 369          * After writing the RTC HH-MM-SS register, the
 370          * SUNXI_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
 371          * be cleared until the real writing operation is finished
 372          */
 373
 374         if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
 375                                 SUNXI_LOSC_CTRL_RTC_HMS_ACC, 50)) {
 376                 dev_err(dev, "Failed to set rtc time.\n");
 377                 return -1;
 378         }
 379
 380         writel(date, chip->base + SUNXI_RTC_YMD);
 381
 382         /*
 383          * After writing the RTC YY-MM-DD register, the
 384          * SUNXI_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
 385          * be cleared until the real writing operation is finished
 386          */
 387
 388         if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
 389                                 SUNXI_LOSC_CTRL_RTC_YMD_ACC, 50)) {
 390                 dev_err(dev, "Failed to set rtc time.\n");
 391                 return -1;
 392         }
 393
 394         return 0;
 395 }
 396
 397 static int sunxi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 398 {
 399         struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
 400
 401         if (!enabled)
 402                 sunxi_rtc_setaie(enabled, chip);
 403
 404         return 0;
 405 }
 406
 407 static const struct rtc_class_ops sunxi_rtc_ops = {
 408         .read_time              = sunxi_rtc_gettime,
 409         .set_time               = sunxi_rtc_settime,
 410         .read_alarm             = sunxi_rtc_getalarm,
 411         .set_alarm              = sunxi_rtc_setalarm,
 412         .alarm_irq_enable       = sunxi_rtc_alarm_irq_enable
 413 };
 414
 415 static const struct of_device_id sunxi_rtc_dt_ids[] = {
 416         { .compatible = "allwinner,sun4i-a10-rtc", .data = &data_year_param[0] },
 417         { .compatible = "allwinner,sun7i-a20-rtc", .data = &data_year_param[1] },
 418         { /* sentinel */ },
 419 };
 420 MODULE_DEVICE_TABLE(of, sunxi_rtc_dt_ids);
 421
 422 static int sunxi_rtc_probe(struct platform_device *pdev)
 423 {
 424         struct sunxi_rtc_dev *chip;
 425         int ret;
 426
 427         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 428         if (!chip)
 429                 return -ENOMEM;
 430
 431         platform_set_drvdata(pdev, chip);
 432         chip->dev = &pdev->dev;
 433
 434         chip->rtc = devm_rtc_allocate_device(&pdev->dev);
 435         if (IS_ERR(chip->rtc))
 436                 return PTR_ERR(chip->rtc);
 437
 438         chip->base = devm_platform_ioremap_resource(pdev, 0);
 439         if (IS_ERR(chip->base))
 440                 return PTR_ERR(chip->base);
 441
 442         chip->irq = platform_get_irq(pdev, 0);
 443         if (chip->irq < 0)
 444                 return chip->irq;
 445         ret = devm_request_irq(&pdev->dev, chip->irq, sunxi_rtc_alarmirq,
 446                         0, dev_name(&pdev->dev), chip);
 447         if (ret) {
 448                 dev_err(&pdev->dev, "Could not request IRQ\n");
 449                 return ret;
 450         }
 451
 452         chip->data_year = of_device_get_match_data(&pdev->dev);
 453         if (!chip->data_year) {
 454                 dev_err(&pdev->dev, "Unable to setup RTC data\n");
 455                 return -ENODEV;
 456         }
 457
 458         /* clear the alarm count value */
 459         writel(0, chip->base + SUNXI_ALRM_DHMS);
 460
 461         /* disable alarm, not generate irq pending */
 462         writel(0, chip->base + SUNXI_ALRM_EN);
 463
 464         /* disable alarm week/cnt irq, unset to cpu */
 465         writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
 466
 467         /* clear alarm week/cnt irq pending */
 468         writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND, chip->base +
 469                         SUNXI_ALRM_IRQ_STA);
 470
 471         chip->rtc->ops = &sunxi_rtc_ops;
 472
 473         return devm_rtc_register_device(chip->rtc);
 474 }
 475
 476 static struct platform_driver sunxi_rtc_driver = {
 477         .probe          = sunxi_rtc_probe,
 478         .driver         = {
 479                 .name           = "sunxi-rtc",
 480                 .of_match_table = sunxi_rtc_dt_ids,
 481         },
 482 };
 483
 484 module_platform_driver(sunxi_rtc_driver);
 485
 486 MODULE_DESCRIPTION("sunxi RTC driver");
 487 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
 488 MODULE_LICENSE("GPL");