drivers/rtc/rtc-pcf8563.c

   1 /*
   2  * An I2C driver for the Philips PCF8563 RTC
   3  * Copyright 2005-06 Tower Technologies
   4  *
   5  * Author: Alessandro Zummo <a.zummo@towertech.it>
   6  * Maintainers: http://www.nslu2-linux.org/
   7  *
   8  * based on the other drivers in this same directory.
   9  *
  10  * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
  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 version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16
  17 #include <linux/i2c.h>
  18 #include <linux/bcd.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/module.h>
  22 #include <linux/of.h>
  23
  24 #define DRV_VERSION "0.4.3"
  25
  26 #define PCF8563_REG_ST1         0x00 /* status */
  27 #define PCF8563_REG_ST2         0x01
  28
  29 #define PCF8563_REG_SC          0x02 /* datetime */
  30 #define PCF8563_REG_MN          0x03
  31 #define PCF8563_REG_HR          0x04
  32 #define PCF8563_REG_DM          0x05
  33 #define PCF8563_REG_DW          0x06
  34 #define PCF8563_REG_MO          0x07
  35 #define PCF8563_REG_YR          0x08
  36
  37 #define PCF8563_REG_AMN         0x09 /* alarm */
  38 #define PCF8563_REG_AHR         0x0A
  39 #define PCF8563_REG_ADM         0x0B
  40 #define PCF8563_REG_ADW         0x0C
  41
  42 #define PCF8563_REG_CLKO        0x0D /* clock out */
  43 #define PCF8563_REG_TMRC        0x0E /* timer control */
  44 #define PCF8563_REG_TMR         0x0F /* timer */
  45
  46 #define PCF8563_SC_LV           0x80 /* low voltage */
  47 #define PCF8563_MO_C            0x80 /* century */
  48
  49 static struct i2c_driver pcf8563_driver;
  50
  51 struct pcf8563 {
  52         struct rtc_device *rtc;
  53         /*
  54          * The meaning of MO_C bit varies by the chip type.
  55          * From PCF8563 datasheet: this bit is toggled when the years
  56          * register overflows from 99 to 00
  57          *   0 indicates the century is 20xx
  58          *   1 indicates the century is 19xx
  59          * From RTC8564 datasheet: this bit indicates change of
  60          * century. When the year digit data overflows from 99 to 00,
  61          * this bit is set. By presetting it to 0 while still in the
  62          * 20th century, it will be set in year 2000, ...
  63          * There seems no reliable way to know how the system use this
  64          * bit.  So let's do it heuristically, assuming we are live in
  65          * 1970...2069.
  66          */
  67         int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
  68         int voltage_low; /* incicates if a low_voltage was detected */
  69 };
  70
  71 /*
  72  * In the routines that deal directly with the pcf8563 hardware, we use
  73  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  74  */
  75 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  76 {
  77         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
  78         unsigned char buf[13] = { PCF8563_REG_ST1 };
  79
  80         struct i2c_msg msgs[] = {
  81                 {/* setup read ptr */
  82                         .addr = client->addr,
  83                         .len = 1,
  84                         .buf = buf
  85                 },
  86                 {/* read status + date */
  87                         .addr = client->addr,
  88                         .flags = I2C_M_RD,
  89                         .len = 13,
  90                         .buf = buf
  91                 },
  92         };
  93
  94         /* read registers */
  95         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  96                 dev_err(&client->dev, "%s: read error\n", __func__);
  97                 return -EIO;
  98         }
  99
 100         if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
 101                 pcf8563->voltage_low = 1;
 102                 dev_info(&client->dev,
 103                         "low voltage detected, date/time is not reliable.\n");
 104         }
 105
 106         dev_dbg(&client->dev,
 107                 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
 108                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
 109                 __func__,
 110                 buf[0], buf[1], buf[2], buf[3],
 111                 buf[4], buf[5], buf[6], buf[7],
 112                 buf[8]);
 113
 114
 115         tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
 116         tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
 117         tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
 118         tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
 119         tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
 120         tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 121         tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
 122         if (tm->tm_year < 70)
 123                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 124         /* detect the polarity heuristically. see note above. */
 125         pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
 126                 (tm->tm_year >= 100) : (tm->tm_year < 100);
 127
 128         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 129                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 130                 __func__,
 131                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 132                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 133
 134         /* the clock can give out invalid datetime, but we cannot return
 135          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 136          */
 137         if (rtc_valid_tm(tm) < 0)
 138                 dev_err(&client->dev, "retrieved date/time is not valid.\n");
 139
 140         return 0;
 141 }
 142
 143 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 144 {
 145         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 146         int i, err;
 147         unsigned char buf[9];
 148
 149         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 150                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 151                 __func__,
 152                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 153                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 154
 155         /* hours, minutes and seconds */
 156         buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
 157         buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
 158         buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
 159
 160         buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
 161
 162         /* month, 1 - 12 */
 163         buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
 164
 165         /* year and century */
 166         buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
 167         if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
 168                 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 169
 170         buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 171
 172         /* write register's data */
 173         for (i = 0; i < 7; i++) {
 174                 unsigned char data[2] = { PCF8563_REG_SC + i,
 175                                                 buf[PCF8563_REG_SC + i] };
 176
 177                 err = i2c_master_send(client, data, sizeof(data));
 178                 if (err != sizeof(data)) {
 179                         dev_err(&client->dev,
 180                                 "%s: err=%d addr=%02x, data=%02x\n",
 181                                 __func__, err, data[0], data[1]);
 182                         return -EIO;
 183                 }
 184         }
 185
 186         return 0;
 187 }
 188
 189 #ifdef CONFIG_RTC_INTF_DEV
 190 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 191 {
 192         struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
 193         struct rtc_time tm;
 194
 195         switch (cmd) {
 196         case RTC_VL_READ:
 197                 if (pcf8563->voltage_low)
 198                         dev_info(dev, "low voltage detected, date/time is not reliable.\n");
 199
 200                 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
 201                                         sizeof(int)))
 202                         return -EFAULT;
 203                 return 0;
 204         case RTC_VL_CLR:
 205                 /*
 206                  * Clear the VL bit in the seconds register in case
 207                  * the time has not been set already (which would
 208                  * have cleared it). This does not really matter
 209                  * because of the cached voltage_low value but do it
 210                  * anyway for consistency.
 211                  */
 212                 if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
 213                         pcf8563_set_datetime(to_i2c_client(dev), &tm);
 214
 215                 /* Clear the cached value. */
 216                 pcf8563->voltage_low = 0;
 217
 218                 return 0;
 219         default:
 220                 return -ENOIOCTLCMD;
 221         }
 222 }
 223 #else
 224 #define pcf8563_rtc_ioctl NULL
 225 #endif
 226
 227 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 228 {
 229         return pcf8563_get_datetime(to_i2c_client(dev), tm);
 230 }
 231
 232 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 233 {
 234         return pcf8563_set_datetime(to_i2c_client(dev), tm);
 235 }
 236
 237 static const struct rtc_class_ops pcf8563_rtc_ops = {
 238         .ioctl          = pcf8563_rtc_ioctl,
 239         .read_time      = pcf8563_rtc_read_time,
 240         .set_time       = pcf8563_rtc_set_time,
 241 };
 242
 243 static int pcf8563_probe(struct i2c_client *client,
 244                                 const struct i2c_device_id *id)
 245 {
 246         struct pcf8563 *pcf8563;
 247
 248         dev_dbg(&client->dev, "%s\n", __func__);
 249
 250         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 251                 return -ENODEV;
 252
 253         pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),
 254                                 GFP_KERNEL);
 255         if (!pcf8563)
 256                 return -ENOMEM;
 257
 258         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 259
 260         i2c_set_clientdata(client, pcf8563);
 261
 262         pcf8563->rtc = devm_rtc_device_register(&client->dev,
 263                                 pcf8563_driver.driver.name,
 264                                 &pcf8563_rtc_ops, THIS_MODULE);
 265
 266         if (IS_ERR(pcf8563->rtc))
 267                 return PTR_ERR(pcf8563->rtc);
 268
 269         return 0;
 270 }
 271
 272 static int pcf8563_remove(struct i2c_client *client)
 273 {
 274         return 0;
 275 }
 276
 277 static const struct i2c_device_id pcf8563_id[] = {
 278         { "pcf8563", 0 },
 279         { "rtc8564", 0 },
 280         { }
 281 };
 282 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 283
 284 #ifdef CONFIG_OF
 285 static const struct of_device_id pcf8563_of_match[] = {
 286         { .compatible = "nxp,pcf8563" },
 287         {}
 288 };
 289 MODULE_DEVICE_TABLE(of, pcf8563_of_match);
 290 #endif
 291
 292 static struct i2c_driver pcf8563_driver = {
 293         .driver         = {
 294                 .name   = "rtc-pcf8563",
 295                 .owner  = THIS_MODULE,
 296                 .of_match_table = of_match_ptr(pcf8563_of_match),
 297         },
 298         .probe          = pcf8563_probe,
 299         .remove         = pcf8563_remove,
 300         .id_table       = pcf8563_id,
 301 };
 302
 303 module_i2c_driver(pcf8563_driver);
 304
 305 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 306 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 307 MODULE_LICENSE("GPL");
 308 MODULE_VERSION(DRV_VERSION);