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 = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 119
 120         /* load 32-bit read-only counter */
 121         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 122         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 123         ticks = base + data;
 124         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 125                 base, data, ticks);
 126
 127         rtc_time_to_tm(ticks, tm);
 128
 129         return 0;
 130 }
 131
 132 static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 133 {
 134         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 135         unsigned char buf[4];
 136         unsigned long ticks, base, data;
 137
 138         if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
 139                 dev_dbg(info->dev, "Set time %d out of range. "
 140                         "Please set time between 1970 to 2038.\n",
 141                         1900 + tm->tm_year);
 142                 return -EINVAL;
 143         }
 144         rtc_tm_to_time(tm, &ticks);
 145
 146         /* load 32-bit read-only counter */
 147         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 148         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 149         base = ticks - data;
 150         dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 151                 base, data, ticks);
 152
 153         pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
 154         pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
 155         pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
 156         pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
 157
 158         if (info->sync)
 159                 info->sync(ticks);
 160         return 0;
 161 }
 162
 163 static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 164 {
 165         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 166         unsigned char buf[8];
 167         unsigned long ticks, base, data;
 168         int ret;
 169
 170         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 171         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 172                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 173         base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 174
 175         pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 176         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 177         ticks = base + data;
 178         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 179                 base, data, ticks);
 180
 181         rtc_time_to_tm(ticks, &alrm->time);
 182         ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
 183         alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
 184         alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
 185         return 0;
 186 }
 187
 188 static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 189 {
 190         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 191         struct rtc_time now_tm, alarm_tm;
 192         unsigned long ticks, base, data;
 193         unsigned char buf[8];
 194         int mask;
 195
 196         pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
 197
 198         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 199         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 200                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 201         base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 202
 203         /* load 32-bit read-only counter */
 204         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 205         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 206         ticks = base + data;
 207         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 208                 base, data, ticks);
 209
 210         rtc_time_to_tm(ticks, &now_tm);
 211         rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
 212         /* get new ticks for alarm in 24 hours */
 213         rtc_tm_to_time(&alarm_tm, &ticks);
 214         data = ticks - base;
 215
 216         buf[0] = data & 0xff;
 217         buf[1] = (data >> 8) & 0xff;
 218         buf[2] = (data >> 16) & 0xff;
 219         buf[3] = (data >> 24) & 0xff;
 220         pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 221         if (alrm->enabled) {
 222                 mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 223                 pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
 224         } else {
 225                 mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 226                 pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
 227                                 ALARM | ALARM_WAKEUP);
 228         }
 229         return 0;
 230 }
 231
 232 static const struct rtc_class_ops pm860x_rtc_ops = {
 233         .read_time      = pm860x_rtc_read_time,
 234         .set_time       = pm860x_rtc_set_time,
 235         .read_alarm     = pm860x_rtc_read_alarm,
 236         .set_alarm      = pm860x_rtc_set_alarm,
 237         .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
 238 };
 239
 240 #ifdef VRTC_CALIBRATION
 241 static void calibrate_vrtc_work(struct work_struct *work)
 242 {
 243         struct pm860x_rtc_info *info = container_of(work,
 244                 struct pm860x_rtc_info, calib_work.work);
 245         unsigned char buf[2];
 246         unsigned int sum, data, mean, vrtc_set;
 247         int i;
 248
 249         for (i = 0, sum = 0; i < 16; i++) {
 250                 msleep(100);
 251                 pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
 252                 data = (buf[0] << 4) | buf[1];
 253                 data = (data * 5400) >> 12;     /* convert to mv */
 254                 sum += data;
 255         }
 256         mean = sum >> 4;
 257         vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
 258         dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
 259
 260         sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
 261         data = sum & 0x3;
 262         if ((mean + 200) < vrtc_set) {
 263                 /* try higher voltage */
 264                 if (++data == 4)
 265                         goto out;
 266                 data = (sum & 0xf8) | (data & 0x3);
 267                 pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 268         } else if ((mean - 200) > vrtc_set) {
 269                 /* try lower voltage */
 270                 if (data-- == 0)
 271                         goto out;
 272                 data = (sum & 0xf8) | (data & 0x3);
 273                 pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 274         } else
 275                 goto out;
 276         dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
 277         /* trigger next calibration since VRTC is updated */
 278         schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 279         return;
 280 out:
 281         /* disable measurement */
 282         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 283         dev_dbg(info->dev, "finish VRTC calibration\n");
 284         return;
 285 }
 286 #endif
 287
 288 #ifdef CONFIG_OF
 289 static int pm860x_rtc_dt_init(struct platform_device *pdev,
 290                               struct pm860x_rtc_info *info)
 291 {
 292         struct device_node *np = pdev->dev.parent->of_node;
 293         int ret;
 294         if (!np)
 295                 return -ENODEV;
 296         np = of_find_node_by_name(np, "rtc");
 297         if (!np) {
 298                 dev_err(&pdev->dev, "failed to find rtc node\n");
 299                 return -ENODEV;
 300         }
 301         ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
 302         if (ret)
 303                 info->vrtc = 0;
 304         return 0;
 305 }
 306 #else
 307 #define pm860x_rtc_dt_init(x, y)        (-1)
 308 #endif
 309
 310 static int pm860x_rtc_probe(struct platform_device *pdev)
 311 {
 312         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 313         struct pm860x_rtc_pdata *pdata = NULL;
 314         struct pm860x_rtc_info *info;
 315         struct rtc_time tm;
 316         unsigned long ticks = 0;
 317         int ret;
 318
 319         pdata = dev_get_platdata(&pdev->dev);
 320
 321         info = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_rtc_info),
 322                             GFP_KERNEL);
 323         if (!info)
 324                 return -ENOMEM;
 325         info->irq = platform_get_irq(pdev, 0);
 326         if (info->irq < 0) {
 327                 dev_err(&pdev->dev, "No IRQ resource!\n");
 328                 return info->irq;
 329         }
 330
 331         info->chip = chip;
 332         info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
 333         info->dev = &pdev->dev;
 334         dev_set_drvdata(&pdev->dev, info);
 335
 336         ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
 337                                         rtc_update_handler, IRQF_ONESHOT, "rtc",
 338                                         info);
 339         if (ret < 0) {
 340                 dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
 341                         info->irq, ret);
 342                 return ret;
 343         }
 344
 345         /* set addresses of 32-bit base value for RTC time */
 346         pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
 347         pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
 348         pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
 349         pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
 350
 351         ret = pm860x_rtc_read_time(&pdev->dev, &tm);
 352         if (ret < 0) {
 353                 dev_err(&pdev->dev, "Failed to read initial time.\n");
 354                 return ret;
 355         }
 356         if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
 357                 tm.tm_year = 70;
 358                 tm.tm_mon = 0;
 359                 tm.tm_mday = 1;
 360                 tm.tm_hour = 0;
 361                 tm.tm_min = 0;
 362                 tm.tm_sec = 0;
 363                 ret = pm860x_rtc_set_time(&pdev->dev, &tm);
 364                 if (ret < 0) {
 365                         dev_err(&pdev->dev, "Failed to set initial time.\n");
 366                         return ret;
 367                 }
 368         }
 369         rtc_tm_to_time(&tm, &ticks);
 370         if (pm860x_rtc_dt_init(pdev, info)) {
 371                 if (pdata && pdata->sync) {
 372                         pdata->sync(ticks);
 373                         info->sync = pdata->sync;
 374                 }
 375         }
 376
 377         info->rtc_dev = devm_rtc_device_register(&pdev->dev, "88pm860x-rtc",
 378                                             &pm860x_rtc_ops, THIS_MODULE);
 379         ret = PTR_ERR(info->rtc_dev);
 380         if (IS_ERR(info->rtc_dev)) {
 381                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 382                 return ret;
 383         }
 384
 385         /*
 386          * enable internal XO instead of internal 3.25MHz clock since it can
 387          * free running in PMIC power-down state.
 388          */
 389         pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
 390
 391 #ifdef VRTC_CALIBRATION
 392         /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
 393         if (pm860x_rtc_dt_init(pdev, info)) {
 394                 if (pdata && pdata->vrtc)
 395                         info->vrtc = pdata->vrtc & 0x3;
 396                 else
 397                         info->vrtc = 1;
 398         }
 399         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
 400
 401         /* calibrate VRTC */
 402         INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
 403         schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 404 #endif  /* VRTC_CALIBRATION */
 405
 406         device_init_wakeup(&pdev->dev, 1);
 407
 408         return 0;
 409 }
 410
 411 static int pm860x_rtc_remove(struct platform_device *pdev)
 412 {
 413         struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
 414
 415 #ifdef VRTC_CALIBRATION
 416         flush_scheduled_work();
 417         /* disable measurement */
 418         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 419 #endif  /* VRTC_CALIBRATION */
 420
 421         return 0;
 422 }
 423
 424 #ifdef CONFIG_PM_SLEEP
 425 static int pm860x_rtc_suspend(struct device *dev)
 426 {
 427         struct platform_device *pdev = to_platform_device(dev);
 428         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 429
 430         if (device_may_wakeup(dev))
 431                 chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
 432         return 0;
 433 }
 434 static int pm860x_rtc_resume(struct device *dev)
 435 {
 436         struct platform_device *pdev = to_platform_device(dev);
 437         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 438
 439         if (device_may_wakeup(dev))
 440                 chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
 441         return 0;
 442 }
 443 #endif
 444
 445 static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
 446
 447 static struct platform_driver pm860x_rtc_driver = {
 448         .driver         = {
 449                 .name   = "88pm860x-rtc",
 450                 .owner  = THIS_MODULE,
 451                 .pm     = &pm860x_rtc_pm_ops,
 452         },
 453         .probe          = pm860x_rtc_probe,
 454         .remove         = pm860x_rtc_remove,
 455 };
 456
 457 module_platform_driver(pm860x_rtc_driver);
 458
 459 MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
 460 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 461 MODULE_LICENSE("GPL");