drivers/rtc/rtc-sun6i.c

   1 /*
   2  * An RTC driver for Allwinner A31/A23
   3  *
   4  * Copyright (c) 2014, Chen-Yu Tsai <wens@csie.org>
   5  *
   6  * based on rtc-sunxi.c
   7  *
   8  * An RTC driver for Allwinner A10/A20
   9  *
  10  * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  20  * more details.
  21  */
  22
  23 #include <linux/delay.h>
  24 #include <linux/err.h>
  25 #include <linux/fs.h>
  26 #include <linux/init.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/io.h>
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/of.h>
  32 #include <linux/of_address.h>
  33 #include <linux/of_device.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/rtc.h>
  36 #include <linux/types.h>
  37
  38 /* Control register */
  39 #define SUN6I_LOSC_CTRL                         0x0000
  40 #define SUN6I_LOSC_CTRL_ALM_DHMS_ACC            BIT(9)
  41 #define SUN6I_LOSC_CTRL_RTC_HMS_ACC             BIT(8)
  42 #define SUN6I_LOSC_CTRL_RTC_YMD_ACC             BIT(7)
  43 #define SUN6I_LOSC_CTRL_ACC_MASK                GENMASK(9, 7)
  44
  45 /* RTC */
  46 #define SUN6I_RTC_YMD                           0x0010
  47 #define SUN6I_RTC_HMS                           0x0014
  48
  49 /* Alarm 0 (counter) */
  50 #define SUN6I_ALRM_COUNTER                      0x0020
  51 #define SUN6I_ALRM_CUR_VAL                      0x0024
  52 #define SUN6I_ALRM_EN                           0x0028
  53 #define SUN6I_ALRM_EN_CNT_EN                    BIT(0)
  54 #define SUN6I_ALRM_IRQ_EN                       0x002c
  55 #define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN            BIT(0)
  56 #define SUN6I_ALRM_IRQ_STA                      0x0030
  57 #define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND         BIT(0)
  58
  59 /* Alarm 1 (wall clock) */
  60 #define SUN6I_ALRM1_EN                          0x0044
  61 #define SUN6I_ALRM1_IRQ_EN                      0x0048
  62 #define SUN6I_ALRM1_IRQ_STA                     0x004c
  63 #define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND       BIT(0)
  64
  65 /* Alarm config */
  66 #define SUN6I_ALARM_CONFIG                      0x0050
  67 #define SUN6I_ALARM_CONFIG_WAKEUP               BIT(0)
  68
  69 /*
  70  * Get date values
  71  */
  72 #define SUN6I_DATE_GET_DAY_VALUE(x)             ((x)  & 0x0000001f)
  73 #define SUN6I_DATE_GET_MON_VALUE(x)             (((x) & 0x00000f00) >> 8)
  74 #define SUN6I_DATE_GET_YEAR_VALUE(x)            (((x) & 0x003f0000) >> 16)
  75 #define SUN6I_LEAP_GET_VALUE(x)                 (((x) & 0x00400000) >> 22)
  76
  77 /*
  78  * Get time values
  79  */
  80 #define SUN6I_TIME_GET_SEC_VALUE(x)             ((x)  & 0x0000003f)
  81 #define SUN6I_TIME_GET_MIN_VALUE(x)             (((x) & 0x00003f00) >> 8)
  82 #define SUN6I_TIME_GET_HOUR_VALUE(x)            (((x) & 0x001f0000) >> 16)
  83
  84 /*
  85  * Set date values
  86  */
  87 #define SUN6I_DATE_SET_DAY_VALUE(x)             ((x)       & 0x0000001f)
  88 #define SUN6I_DATE_SET_MON_VALUE(x)             ((x) <<  8 & 0x00000f00)
  89 #define SUN6I_DATE_SET_YEAR_VALUE(x)            ((x) << 16 & 0x003f0000)
  90 #define SUN6I_LEAP_SET_VALUE(x)                 ((x) << 22 & 0x00400000)
  91
  92 /*
  93  * Set time values
  94  */
  95 #define SUN6I_TIME_SET_SEC_VALUE(x)             ((x)       & 0x0000003f)
  96 #define SUN6I_TIME_SET_MIN_VALUE(x)             ((x) <<  8 & 0x00003f00)
  97 #define SUN6I_TIME_SET_HOUR_VALUE(x)            ((x) << 16 & 0x001f0000)
  98
  99 /*
 100  * The year parameter passed to the driver is usually an offset relative to
 101  * the year 1900. This macro is used to convert this offset to another one
 102  * relative to the minimum year allowed by the hardware.
 103  *
 104  * The year range is 1970 - 2033. This range is selected to match Allwinner's
 105  * driver, even though it is somewhat limited.
 106  */
 107 #define SUN6I_YEAR_MIN                          1970
 108 #define SUN6I_YEAR_MAX                          2033
 109 #define SUN6I_YEAR_OFF                          (SUN6I_YEAR_MIN - 1900)
 110
 111 struct sun6i_rtc_dev {
 112         struct rtc_device *rtc;
 113         struct device *dev;
 114         void __iomem *base;
 115         int irq;
 116         unsigned long alarm;
 117 };
 118
 119 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
 120 {
 121         struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
 122         u32 val;
 123
 124         val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
 125
 126         if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
 127                 val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
 128                 writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
 129
 130                 rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
 131
 132                 return IRQ_HANDLED;
 133         }
 134
 135         return IRQ_NONE;
 136 }
 137
 138 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
 139 {
 140         u32 alrm_val = 0;
 141         u32 alrm_irq_val = 0;
 142         u32 alrm_wake_val = 0;
 143
 144         if (to) {
 145                 alrm_val = SUN6I_ALRM_EN_CNT_EN;
 146                 alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
 147                 alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
 148         } else {
 149                 writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
 150                        chip->base + SUN6I_ALRM_IRQ_STA);
 151         }
 152
 153         writel(alrm_val, chip->base + SUN6I_ALRM_EN);
 154         writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
 155         writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
 156 }
 157
 158 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 159 {
 160         struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
 161         u32 date, time;
 162
 163         /*
 164          * read again in case it changes
 165          */
 166         do {
 167                 date = readl(chip->base + SUN6I_RTC_YMD);
 168                 time = readl(chip->base + SUN6I_RTC_HMS);
 169         } while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
 170                  (time != readl(chip->base + SUN6I_RTC_HMS)));
 171
 172         rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
 173         rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
 174         rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
 175
 176         rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
 177         rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
 178         rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
 179
 180         rtc_tm->tm_mon  -= 1;
 181
 182         /*
 183          * switch from (data_year->min)-relative offset to
 184          * a (1900)-relative one
 185          */
 186         rtc_tm->tm_year += SUN6I_YEAR_OFF;
 187
 188         return rtc_valid_tm(rtc_tm);
 189 }
 190
 191 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 192 {
 193         struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
 194         u32 alrm_st;
 195         u32 alrm_en;
 196
 197         alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
 198         alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
 199         wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
 200         wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
 201         rtc_time_to_tm(chip->alarm, &wkalrm->time);
 202
 203         return 0;
 204 }
 205
 206 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 207 {
 208         struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
 209         struct rtc_time *alrm_tm = &wkalrm->time;
 210         struct rtc_time tm_now;
 211         unsigned long time_now = 0;
 212         unsigned long time_set = 0;
 213         unsigned long time_gap = 0;
 214         int ret = 0;
 215
 216         ret = sun6i_rtc_gettime(dev, &tm_now);
 217         if (ret < 0) {
 218                 dev_err(dev, "Error in getting time\n");
 219                 return -EINVAL;
 220         }
 221
 222         rtc_tm_to_time(alrm_tm, &time_set);
 223         rtc_tm_to_time(&tm_now, &time_now);
 224         if (time_set <= time_now) {
 225                 dev_err(dev, "Date to set in the past\n");
 226                 return -EINVAL;
 227         }
 228
 229         time_gap = time_set - time_now;
 230
 231         if (time_gap > U32_MAX) {
 232                 dev_err(dev, "Date too far in the future\n");
 233                 return -EINVAL;
 234         }
 235
 236         sun6i_rtc_setaie(0, chip);
 237         writel(0, chip->base + SUN6I_ALRM_COUNTER);
 238         usleep_range(100, 300);
 239
 240         writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
 241         chip->alarm = time_set;
 242
 243         sun6i_rtc_setaie(wkalrm->enabled, chip);
 244
 245         return 0;
 246 }
 247
 248 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
 249                           unsigned int mask, unsigned int ms_timeout)
 250 {
 251         const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
 252         u32 reg;
 253
 254         do {
 255                 reg = readl(chip->base + offset);
 256                 reg &= mask;
 257
 258                 if (!reg)
 259                         return 0;
 260
 261         } while (time_before(jiffies, timeout));
 262
 263         return -ETIMEDOUT;
 264 }
 265
 266 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
 267 {
 268         struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
 269         u32 date = 0;
 270         u32 time = 0;
 271         int year;
 272
 273         year = rtc_tm->tm_year + 1900;
 274         if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) {
 275                 dev_err(dev, "rtc only supports year in range %d - %d\n",
 276                         SUN6I_YEAR_MIN, SUN6I_YEAR_MAX);
 277                 return -EINVAL;
 278         }
 279
 280         rtc_tm->tm_year -= SUN6I_YEAR_OFF;
 281         rtc_tm->tm_mon += 1;
 282
 283         date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
 284                 SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
 285                 SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
 286
 287         if (is_leap_year(year))
 288                 date |= SUN6I_LEAP_SET_VALUE(1);
 289
 290         time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
 291                 SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
 292                 SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
 293
 294         /* Check whether registers are writable */
 295         if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
 296                            SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
 297                 dev_err(dev, "rtc is still busy.\n");
 298                 return -EBUSY;
 299         }
 300
 301         writel(time, chip->base + SUN6I_RTC_HMS);
 302
 303         /*
 304          * After writing the RTC HH-MM-SS register, the
 305          * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
 306          * be cleared until the real writing operation is finished
 307          */
 308
 309         if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
 310                            SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
 311                 dev_err(dev, "Failed to set rtc time.\n");
 312                 return -ETIMEDOUT;
 313         }
 314
 315         writel(date, chip->base + SUN6I_RTC_YMD);
 316
 317         /*
 318          * After writing the RTC YY-MM-DD register, the
 319          * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
 320          * be cleared until the real writing operation is finished
 321          */
 322
 323         if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
 324                            SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
 325                 dev_err(dev, "Failed to set rtc time.\n");
 326                 return -ETIMEDOUT;
 327         }
 328
 329         return 0;
 330 }
 331
 332 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 333 {
 334         struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
 335
 336         if (!enabled)
 337                 sun6i_rtc_setaie(enabled, chip);
 338
 339         return 0;
 340 }
 341
 342 static const struct rtc_class_ops sun6i_rtc_ops = {
 343         .read_time              = sun6i_rtc_gettime,
 344         .set_time               = sun6i_rtc_settime,
 345         .read_alarm             = sun6i_rtc_getalarm,
 346         .set_alarm              = sun6i_rtc_setalarm,
 347         .alarm_irq_enable       = sun6i_rtc_alarm_irq_enable
 348 };
 349
 350 static int sun6i_rtc_probe(struct platform_device *pdev)
 351 {
 352         struct sun6i_rtc_dev *chip;
 353         struct resource *res;
 354         int ret;
 355
 356         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 357         if (!chip)
 358                 return -ENOMEM;
 359
 360         platform_set_drvdata(pdev, chip);
 361         chip->dev = &pdev->dev;
 362
 363         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 364         chip->base = devm_ioremap_resource(&pdev->dev, res);
 365         if (IS_ERR(chip->base))
 366                 return PTR_ERR(chip->base);
 367
 368         chip->irq = platform_get_irq(pdev, 0);
 369         if (chip->irq < 0) {
 370                 dev_err(&pdev->dev, "No IRQ resource\n");
 371                 return chip->irq;
 372         }
 373
 374         ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
 375                                0, dev_name(&pdev->dev), chip);
 376         if (ret) {
 377                 dev_err(&pdev->dev, "Could not request IRQ\n");
 378                 return ret;
 379         }
 380
 381         /* clear the alarm counter value */
 382         writel(0, chip->base + SUN6I_ALRM_COUNTER);
 383
 384         /* disable counter alarm */
 385         writel(0, chip->base + SUN6I_ALRM_EN);
 386
 387         /* disable counter alarm interrupt */
 388         writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
 389
 390         /* disable week alarm */
 391         writel(0, chip->base + SUN6I_ALRM1_EN);
 392
 393         /* disable week alarm interrupt */
 394         writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
 395
 396         /* clear counter alarm pending interrupts */
 397         writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
 398                chip->base + SUN6I_ALRM_IRQ_STA);
 399
 400         /* clear week alarm pending interrupts */
 401         writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
 402                chip->base + SUN6I_ALRM1_IRQ_STA);
 403
 404         /* disable alarm wakeup */
 405         writel(0, chip->base + SUN6I_ALARM_CONFIG);
 406
 407         chip->rtc = rtc_device_register("rtc-sun6i", &pdev->dev,
 408                                         &sun6i_rtc_ops, THIS_MODULE);
 409         if (IS_ERR(chip->rtc)) {
 410                 dev_err(&pdev->dev, "unable to register device\n");
 411                 return PTR_ERR(chip->rtc);
 412         }
 413
 414         dev_info(&pdev->dev, "RTC enabled\n");
 415
 416         return 0;
 417 }
 418
 419 static int sun6i_rtc_remove(struct platform_device *pdev)
 420 {
 421         struct sun6i_rtc_dev *chip = platform_get_drvdata(pdev);
 422
 423         rtc_device_unregister(chip->rtc);
 424
 425         return 0;
 426 }
 427
 428 static const struct of_device_id sun6i_rtc_dt_ids[] = {
 429         { .compatible = "allwinner,sun6i-a31-rtc" },
 430         { /* sentinel */ },
 431 };
 432 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
 433
 434 static struct platform_driver sun6i_rtc_driver = {
 435         .probe          = sun6i_rtc_probe,
 436         .remove         = sun6i_rtc_remove,
 437         .driver         = {
 438                 .name           = "sun6i-rtc",
 439                 .of_match_table = sun6i_rtc_dt_ids,
 440         },
 441 };
 442
 443 module_platform_driver(sun6i_rtc_driver);
 444
 445 MODULE_DESCRIPTION("sun6i RTC driver");
 446 MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
 447 MODULE_LICENSE("GPL");