LXR linux/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
 111struct 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
 119static 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
 138static 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
 158static 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
 191static 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
 206static 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
 248static 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
 266static 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
 332static 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
 342static 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
 350static 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
 419static 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
 428static const struct of_device_id sun6i_rtc_dt_ids[] = {
 429        { .compatible = "allwinner,sun6i-a31-rtc" },
 430        { /* sentinel */ },
 431};
 432MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
 433
 434static 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
 443module_platform_driver(sun6i_rtc_driver);
 444
 445MODULE_DESCRIPTION("sun6i RTC driver");
 446MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
 447MODULE_LICENSE("GPL");
 448