drivers/rtc/rtc-88pm860x.c

   1 /*
   2  * Real Time Clock driver for Marvell 88PM860x PMIC
   3  *
   4  * Copyright (c) 2010 Marvell International Ltd.
   5  * Author:      Haojian Zhuang <haojian.zhuang@marvell.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/slab.h>
  17 #include <linux/mutex.h>
  18 #include <linux/rtc.h>
  19 #include <linux/delay.h>
  20 #include <linux/mfd/core.h>
  21 #include <linux/mfd/88pm860x.h>
  22
  23 #define VRTC_CALIBRATION
  24
  25 struct pm860x_rtc_info {
  26         struct pm860x_chip      *chip;
  27         struct i2c_client       *i2c;
  28         struct rtc_device       *rtc_dev;
  29         struct device           *dev;
  30         struct delayed_work     calib_work;
  31
  32         int                     irq;
  33         int                     vrtc;
  34         int                     (*sync)(unsigned int ticks);
  35 };
  36
  37 #define REG_VRTC_MEAS1          0x7D
  38
  39 #define REG0_ADDR               0xB0
  40 #define REG1_ADDR               0xB2
  41 #define REG2_ADDR               0xB4
  42 #define REG3_ADDR               0xB6
  43
  44 #define REG0_DATA               0xB1
  45 #define REG1_DATA               0xB3
  46 #define REG2_DATA               0xB5
  47 #define REG3_DATA               0xB7
  48
  49 /* bit definitions of Measurement Enable Register 2 (0x51) */
  50 #define MEAS2_VRTC              (1 << 0)
  51
  52 /* bit definitions of RTC Register 1 (0xA0) */
  53 #define ALARM_EN                (1 << 3)
  54 #define ALARM_WAKEUP            (1 << 4)
  55 #define ALARM                   (1 << 5)
  56 #define RTC1_USE_XO             (1 << 7)
  57
  58 #define VRTC_CALIB_INTERVAL     (HZ * 60 * 10)          /* 10 minutes */
  59
  60 static irqreturn_t rtc_update_handler(int irq, void *data)
  61 {
  62         struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
  63         int mask;
  64
  65         mask = ALARM | ALARM_WAKEUP;
  66         pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
  67         rtc_update_irq(info->rtc_dev, 1, RTC_AF);
  68         return IRQ_HANDLED;
  69 }
  70
  71 static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  72 {
  73         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
  74
  75         if (enabled)
  76                 pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
  77         else
  78                 pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
  79         return 0;
  80 }
  81
  82 /*
  83  * Calculate the next alarm time given the requested alarm time mask
  84  * and the current time.
  85  */
  86 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
  87                                 struct rtc_time *alrm)
  88 {
  89         unsigned long next_time;
  90         unsigned long now_time;
  91
  92         next->tm_year = now->tm_year;
  93         next->tm_mon = now->tm_mon;
  94         next->tm_mday = now->tm_mday;
  95         next->tm_hour = alrm->tm_hour;
  96         next->tm_min = alrm->tm_min;
  97         next->tm_sec = alrm->tm_sec;
  98
  99         rtc_tm_to_time(now, &now_time);
 100         rtc_tm_to_time(next, &next_time);
 101
 102         if (next_time < now_time) {
 103                 /* Advance one day */
 104                 next_time += 60 * 60 * 24;
 105                 rtc_time_to_tm(next_time, next);
 106         }
 107 }
 108
 109 static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 110 {
 111         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 112         unsigned char buf[8];
 113         unsigned long ticks, base, data;
 114
 115         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 116         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 117                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 118         base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
 119                 (buf[5] << 8) | buf[7];
 120
 121         /* load 32-bit read-only counter */
 122         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 123         data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
 124                 (buf[1] << 8) | buf[0];
 125         ticks = base + data;
 126         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 127                 base, data, ticks);
 128
 129         rtc_time_to_tm(ticks, tm);
 130
 131         return 0;
 132 }
 133
 134 static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 135 {
 136         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 137         unsigned char buf[4];
 138         unsigned long ticks, base, data;
 139
 140         if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
 141                 dev_dbg(info->dev, "Set time %d out of range. "
 142                         "Please set time between 1970 to 2038.\n",
 143                         1900 + tm->tm_year);
 144                 return -EINVAL;
 145         }
 146         rtc_tm_to_time(tm, &ticks);
 147
 148         /* load 32-bit read-only counter */
 149         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 150         data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
 151                 (buf[1] << 8) | buf[0];
 152         base = ticks - data;
 153         dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 154                 base, data, ticks);
 155
 156         pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
 157         pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
 158         pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
 159         pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
 160
 161         if (info->sync)
 162                 info->sync(ticks);
 163         return 0;
 164 }
 165
 166 static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 167 {
 168         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 169         unsigned char buf[8];
 170         unsigned long ticks, base, data;
 171         int ret;
 172
 173         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 174         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 175                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 176         base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
 177                 (buf[5] << 8) | buf[7];
 178
 179         pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 180         data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
 181                 (buf[1] << 8) | buf[0];
 182         ticks = base + data;
 183         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 184                 base, data, ticks);
 185
 186         rtc_time_to_tm(ticks, &alrm->time);
 187         ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
 188         alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
 189         alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
 190         return 0;
 191 }
 192
 193 static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 194 {
 195         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 196         struct rtc_time now_tm, alarm_tm;
 197         unsigned long ticks, base, data;
 198         unsigned char buf[8];
 199         int mask;
 200
 201         pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
 202
 203         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 204         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 205                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 206         base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
 207                 (buf[5] << 8) | buf[7];
 208
 209         /* load 32-bit read-only counter */
 210         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 211         data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
 212                 (buf[1] << 8) | buf[0];
 213         ticks = base + data;
 214         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 215                 base, data, ticks);
 216
 217         rtc_time_to_tm(ticks, &now_tm);
 218         rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
 219         /* get new ticks for alarm in 24 hours */
 220         rtc_tm_to_time(&alarm_tm, &ticks);
 221         data = ticks - base;
 222
 223         buf[0] = data & 0xff;
 224         buf[1] = (data >> 8) & 0xff;
 225         buf[2] = (data >> 16) & 0xff;
 226         buf[3] = (data >> 24) & 0xff;
 227         pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 228         if (alrm->enabled) {
 229                 mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 230                 pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
 231         } else {
 232                 mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 233                 pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
 234                                 ALARM | ALARM_WAKEUP);
 235         }
 236         return 0;
 237 }
 238
 239 static const struct rtc_class_ops pm860x_rtc_ops = {
 240         .read_time      = pm860x_rtc_read_time,
 241         .set_time       = pm860x_rtc_set_time,
 242         .read_alarm     = pm860x_rtc_read_alarm,
 243         .set_alarm      = pm860x_rtc_set_alarm,
 244         .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
 245 };
 246
 247 #ifdef VRTC_CALIBRATION
 248 static void calibrate_vrtc_work(struct work_struct *work)
 249 {
 250         struct pm860x_rtc_info *info = container_of(work,
 251                 struct pm860x_rtc_info, calib_work.work);
 252         unsigned char buf[2];
 253         unsigned int sum, data, mean, vrtc_set;
 254         int i;
 255
 256         for (i = 0, sum = 0; i < 16; i++) {
 257                 msleep(100);
 258                 pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
 259                 data = (buf[0] << 4) | buf[1];
 260                 data = (data * 5400) >> 12;     /* convert to mv */
 261                 sum += data;
 262         }
 263         mean = sum >> 4;
 264         vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
 265         dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
 266
 267         sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
 268         data = sum & 0x3;
 269         if ((mean + 200) < vrtc_set) {
 270                 /* try higher voltage */
 271                 if (++data == 4)
 272                         goto out;
 273                 data = (sum & 0xf8) | (data & 0x3);
 274                 pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 275         } else if ((mean - 200) > vrtc_set) {
 276                 /* try lower voltage */
 277                 if (data-- == 0)
 278                         goto out;
 279                 data = (sum & 0xf8) | (data & 0x3);
 280                 pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 281         } else
 282                 goto out;
 283         dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
 284         /* trigger next calibration since VRTC is updated */
 285         schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 286         return;
 287 out:
 288         /* disable measurement */
 289         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 290         dev_dbg(info->dev, "finish VRTC calibration\n");
 291         return;
 292 }
 293 #endif
 294
 295 #ifdef CONFIG_OF
 296 static int pm860x_rtc_dt_init(struct platform_device *pdev,
 297                               struct pm860x_rtc_info *info)
 298 {
 299         struct device_node *np = pdev->dev.parent->of_node;
 300         int ret;
 301         if (!np)
 302                 return -ENODEV;
 303         np = of_get_child_by_name(np, "rtc");
 304         if (!np) {
 305                 dev_err(&pdev->dev, "failed to find rtc node\n");
 306                 return -ENODEV;
 307         }
 308         ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
 309         if (ret)
 310                 info->vrtc = 0;
 311         of_node_put(np);
 312         return 0;
 313 }
 314 #else
 315 #define pm860x_rtc_dt_init(x, y)        (-1)
 316 #endif
 317
 318 static int pm860x_rtc_probe(struct platform_device *pdev)
 319 {
 320         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 321         struct pm860x_rtc_pdata *pdata = NULL;
 322         struct pm860x_rtc_info *info;
 323         struct rtc_time tm;
 324         unsigned long ticks = 0;
 325         int ret;
 326
 327         pdata = dev_get_platdata(&pdev->dev);
 328
 329         info = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_rtc_info),
 330                             GFP_KERNEL);
 331         if (!info)
 332                 return -ENOMEM;
 333         info->irq = platform_get_irq(pdev, 0);
 334         if (info->irq < 0) {
 335                 dev_err(&pdev->dev, "No IRQ resource!\n");
 336                 return info->irq;
 337         }
 338
 339         info->chip = chip;
 340         info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
 341         info->dev = &pdev->dev;
 342         dev_set_drvdata(&pdev->dev, info);
 343
 344         ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
 345                                         rtc_update_handler, IRQF_ONESHOT, "rtc",
 346                                         info);
 347         if (ret < 0) {
 348                 dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
 349                         info->irq, ret);
 350                 return ret;
 351         }
 352
 353         /* set addresses of 32-bit base value for RTC time */
 354         pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
 355         pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
 356         pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
 357         pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
 358
 359         ret = pm860x_rtc_read_time(&pdev->dev, &tm);
 360         if (ret < 0) {
 361                 dev_err(&pdev->dev, "Failed to read initial time.\n");
 362                 return ret;
 363         }
 364         if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
 365                 tm.tm_year = 70;
 366                 tm.tm_mon = 0;
 367                 tm.tm_mday = 1;
 368                 tm.tm_hour = 0;
 369                 tm.tm_min = 0;
 370                 tm.tm_sec = 0;
 371                 ret = pm860x_rtc_set_time(&pdev->dev, &tm);
 372                 if (ret < 0) {
 373                         dev_err(&pdev->dev, "Failed to set initial time.\n");
 374                         return ret;
 375                 }
 376         }
 377         rtc_tm_to_time(&tm, &ticks);
 378         if (pm860x_rtc_dt_init(pdev, info)) {
 379                 if (pdata && pdata->sync) {
 380                         pdata->sync(ticks);
 381                         info->sync = pdata->sync;
 382                 }
 383         }
 384
 385         info->rtc_dev = devm_rtc_device_register(&pdev->dev, "88pm860x-rtc",
 386                                             &pm860x_rtc_ops, THIS_MODULE);
 387         ret = PTR_ERR(info->rtc_dev);
 388         if (IS_ERR(info->rtc_dev)) {
 389                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 390                 return ret;
 391         }
 392
 393         /*
 394          * enable internal XO instead of internal 3.25MHz clock since it can
 395          * free running in PMIC power-down state.
 396          */
 397         pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
 398
 399 #ifdef VRTC_CALIBRATION
 400         /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
 401         if (pm860x_rtc_dt_init(pdev, info)) {
 402                 if (pdata && pdata->vrtc)
 403                         info->vrtc = pdata->vrtc & 0x3;
 404                 else
 405                         info->vrtc = 1;
 406         }
 407         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
 408
 409         /* calibrate VRTC */
 410         INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
 411         schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 412 #endif  /* VRTC_CALIBRATION */
 413
 414         device_init_wakeup(&pdev->dev, 1);
 415
 416         return 0;
 417 }
 418
 419 static int pm860x_rtc_remove(struct platform_device *pdev)
 420 {
 421         struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
 422
 423 #ifdef VRTC_CALIBRATION
 424         cancel_delayed_work_sync(&info->calib_work);
 425         /* disable measurement */
 426         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 427 #endif  /* VRTC_CALIBRATION */
 428
 429         return 0;
 430 }
 431
 432 #ifdef CONFIG_PM_SLEEP
 433 static int pm860x_rtc_suspend(struct device *dev)
 434 {
 435         struct platform_device *pdev = to_platform_device(dev);
 436         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 437
 438         if (device_may_wakeup(dev))
 439                 chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
 440         return 0;
 441 }
 442 static int pm860x_rtc_resume(struct device *dev)
 443 {
 444         struct platform_device *pdev = to_platform_device(dev);
 445         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 446
 447         if (device_may_wakeup(dev))
 448                 chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
 449         return 0;
 450 }
 451 #endif
 452
 453 static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
 454
 455 static struct platform_driver pm860x_rtc_driver = {
 456         .driver         = {
 457                 .name   = "88pm860x-rtc",
 458                 .pm     = &pm860x_rtc_pm_ops,
 459         },
 460         .probe          = pm860x_rtc_probe,
 461         .remove         = pm860x_rtc_remove,
 462 };
 463
 464 module_platform_driver(pm860x_rtc_driver);
 465
 466 MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
 467 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 468 MODULE_LICENSE("GPL");