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