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