drivers/rtc/ds3231.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2006
   4  * Markus Klotzbuecher, mk@denx.de
   5  *
   6  * (C) Copyright 2019 NXP
   7  * Chuanhua Han <chuanhua.han@nxp.com>
   8  */
   9
  10 /*
  11  * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
  12  * Extremly Accurate DS3231 Real Time Clock (RTC).
  13  *
  14  * copied from ds1337.c
  15  */
  16
  17 #include <common.h>
  18 #include <command.h>
  19 #include <dm.h>
  20 #include <rtc.h>
  21 #include <i2c.h>
  22
  23 /*
  24  * RTC register addresses
  25  */
  26 #define RTC_SEC_REG_ADDR        0x0
  27 #define RTC_MIN_REG_ADDR        0x1
  28 #define RTC_HR_REG_ADDR         0x2
  29 #define RTC_DAY_REG_ADDR        0x3
  30 #define RTC_DATE_REG_ADDR       0x4
  31 #define RTC_MON_REG_ADDR        0x5
  32 #define RTC_YR_REG_ADDR         0x6
  33 #define RTC_CTL_REG_ADDR        0x0e
  34 #define RTC_STAT_REG_ADDR       0x0f
  35
  36
  37 /*
  38  * RTC control register bits
  39  */
  40 #define RTC_CTL_BIT_A1IE        0x1     /* Alarm 1 interrupt enable     */
  41 #define RTC_CTL_BIT_A2IE        0x2     /* Alarm 2 interrupt enable     */
  42 #define RTC_CTL_BIT_INTCN       0x4     /* Interrupt control            */
  43 #define RTC_CTL_BIT_RS1         0x8     /* Rate select 1                */
  44 #define RTC_CTL_BIT_RS2         0x10    /* Rate select 2                */
  45 #define RTC_CTL_BIT_DOSC        0x80    /* Disable Oscillator           */
  46
  47 /*
  48  * RTC status register bits
  49  */
  50 #define RTC_STAT_BIT_A1F        0x1     /* Alarm 1 flag                 */
  51 #define RTC_STAT_BIT_A2F        0x2     /* Alarm 2 flag                 */
  52 #define RTC_STAT_BIT_OSF        0x80    /* Oscillator stop flag         */
  53 #define RTC_STAT_BIT_BB32KHZ    0x40    /* Battery backed 32KHz Output  */
  54 #define RTC_STAT_BIT_EN32KHZ    0x8     /* Enable 32KHz Output  */
  55
  56
  57 #if !CONFIG_IS_ENABLED(DM_RTC)
  58 static uchar rtc_read (uchar reg);
  59 static void rtc_write (uchar reg, uchar val);
  60
  61
  62 /*
  63  * Get the current time from the RTC
  64  */
  65 int rtc_get (struct rtc_time *tmp)
  66 {
  67         int rel = 0;
  68         uchar sec, min, hour, mday, wday, mon_cent, year, control, status;
  69
  70         control = rtc_read (RTC_CTL_REG_ADDR);
  71         status = rtc_read (RTC_STAT_REG_ADDR);
  72         sec = rtc_read (RTC_SEC_REG_ADDR);
  73         min = rtc_read (RTC_MIN_REG_ADDR);
  74         hour = rtc_read (RTC_HR_REG_ADDR);
  75         wday = rtc_read (RTC_DAY_REG_ADDR);
  76         mday = rtc_read (RTC_DATE_REG_ADDR);
  77         mon_cent = rtc_read (RTC_MON_REG_ADDR);
  78         year = rtc_read (RTC_YR_REG_ADDR);
  79
  80         debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
  81                 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
  82                 year, mon_cent, mday, wday, hour, min, sec, control, status);
  83
  84         if (status & RTC_STAT_BIT_OSF) {
  85                 printf ("### Warning: RTC oscillator has stopped\n");
  86                 /* clear the OSF flag */
  87                 rtc_write (RTC_STAT_REG_ADDR,
  88                            rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
  89                 rel = -1;
  90         }
  91
  92         tmp->tm_sec  = bcd2bin (sec & 0x7F);
  93         tmp->tm_min  = bcd2bin (min & 0x7F);
  94         tmp->tm_hour = bcd2bin (hour & 0x3F);
  95         tmp->tm_mday = bcd2bin (mday & 0x3F);
  96         tmp->tm_mon  = bcd2bin (mon_cent & 0x1F);
  97         tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
  98         tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
  99         tmp->tm_yday = 0;
 100         tmp->tm_isdst= 0;
 101
 102         debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 103                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 104                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 105
 106         return rel;
 107 }
 108
 109
 110 /*
 111  * Set the RTC
 112  */
 113 int rtc_set (struct rtc_time *tmp)
 114 {
 115         uchar century;
 116
 117         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 118                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 119                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 120
 121         rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
 122
 123         century = (tmp->tm_year >= 2000) ? 0x80 : 0;
 124         rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);
 125
 126         rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
 127         rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
 128         rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
 129         rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
 130         rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
 131
 132         return 0;
 133 }
 134
 135
 136 /*
 137  * Reset the RTC.  We also enable the oscillator output on the
 138  * SQW/INTB* pin and program it for 32,768 Hz output. Note that
 139  * according to the datasheet, turning on the square wave output
 140  * increases the current drain on the backup battery from about
 141  * 600 nA to 2uA.
 142  */
 143 void rtc_reset (void)
 144 {
 145         rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
 146 }
 147
 148 /*
 149  * Enable 32KHz output
 150  */
 151 #ifdef CONFIG_RTC_ENABLE_32KHZ_OUTPUT
 152 void rtc_enable_32khz_output(void)
 153 {
 154         rtc_write(RTC_STAT_REG_ADDR,
 155                   RTC_STAT_BIT_BB32KHZ | RTC_STAT_BIT_EN32KHZ);
 156 }
 157 #endif
 158
 159 /*
 160  * Helper functions
 161  */
 162
 163 static
 164 uchar rtc_read (uchar reg)
 165 {
 166         return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
 167 }
 168
 169
 170 static void rtc_write (uchar reg, uchar val)
 171 {
 172         i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
 173 }
 174 #else
 175 static int ds3231_rtc_get(struct udevice *dev, struct rtc_time *tmp)
 176 {
 177         uchar sec, min, hour, mday, wday, mon_cent, year, status;
 178
 179         status = dm_i2c_reg_read(dev, RTC_STAT_REG_ADDR);
 180         sec = dm_i2c_reg_read(dev, RTC_SEC_REG_ADDR);
 181         min = dm_i2c_reg_read(dev, RTC_MIN_REG_ADDR);
 182         hour = dm_i2c_reg_read(dev, RTC_HR_REG_ADDR);
 183         wday = dm_i2c_reg_read(dev, RTC_DAY_REG_ADDR);
 184         mday = dm_i2c_reg_read(dev, RTC_DATE_REG_ADDR);
 185         mon_cent = dm_i2c_reg_read(dev, RTC_MON_REG_ADDR);
 186         year = dm_i2c_reg_read(dev, RTC_YR_REG_ADDR);
 187
 188         if (status & RTC_STAT_BIT_OSF) {
 189                 printf("### Warning: RTC oscillator has stopped\n");
 190                 /* clear the OSF flag */
 191                 dm_i2c_reg_write(dev, RTC_STAT_REG_ADDR,
 192                                  dm_i2c_reg_read(dev, RTC_STAT_REG_ADDR)
 193                                                 & ~RTC_STAT_BIT_OSF);
 194                 return -EINVAL;
 195         }
 196
 197         tmp->tm_sec  = bcd2bin(sec & 0x7F);
 198         tmp->tm_min  = bcd2bin(min & 0x7F);
 199         tmp->tm_hour = bcd2bin(hour & 0x3F);
 200         tmp->tm_mday = bcd2bin(mday & 0x3F);
 201         tmp->tm_mon  = bcd2bin(mon_cent & 0x1F);
 202         tmp->tm_year = bcd2bin(year) + ((mon_cent & 0x80) ? 2000 : 1900);
 203         tmp->tm_wday = bcd2bin((wday - 1) & 0x07);
 204         tmp->tm_yday = 0;
 205         tmp->tm_isdst = 0;
 206
 207         debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 208               tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 209               tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 210
 211         return 0;
 212 }
 213
 214 static int ds3231_rtc_set(struct udevice *dev, const struct rtc_time *tmp)
 215 {
 216         uchar century;
 217
 218         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 219               tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 220               tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 221
 222         dm_i2c_reg_write(dev, RTC_YR_REG_ADDR, bin2bcd(tmp->tm_year % 100));
 223
 224         century = (tmp->tm_year >= 2000) ? 0x80 : 0;
 225         dm_i2c_reg_write(dev, RTC_MON_REG_ADDR, bin2bcd(tmp->tm_mon) | century);
 226
 227         dm_i2c_reg_write(dev, RTC_DAY_REG_ADDR, bin2bcd(tmp->tm_wday + 1));
 228         dm_i2c_reg_write(dev, RTC_DATE_REG_ADDR, bin2bcd(tmp->tm_mday));
 229         dm_i2c_reg_write(dev, RTC_HR_REG_ADDR, bin2bcd(tmp->tm_hour));
 230         dm_i2c_reg_write(dev, RTC_MIN_REG_ADDR, bin2bcd(tmp->tm_min));
 231         dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR, bin2bcd(tmp->tm_sec));
 232
 233         return 0;
 234 }
 235
 236 static int ds3231_rtc_reset(struct udevice *dev)
 237 {
 238         int ret;
 239
 240         ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR,
 241                                RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
 242         if (ret < 0)
 243                 return ret;
 244
 245         return 0;
 246 }
 247
 248 static int ds3231_probe(struct udevice *dev)
 249 {
 250         i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
 251                         DM_I2C_CHIP_WR_ADDRESS);
 252
 253         return 0;
 254 }
 255
 256 #ifdef CONFIG_RTC_ENABLE_32KHZ_OUTPUT
 257 int rtc_enable_32khz_output(int busnum, int chip_addr)
 258 {
 259         int ret;
 260         struct udevice *dev;
 261
 262         ret = i2c_get_chip_for_busnum(busnum, chip_addr, 1, &dev);
 263         if (!ret)
 264                 ret = dm_i2c_reg_write(dev, RTC_STAT_REG_ADDR,
 265                                        RTC_STAT_BIT_BB32KHZ |
 266                                        RTC_STAT_BIT_EN32KHZ);
 267         return ret;
 268 }
 269 #endif
 270
 271 static const struct rtc_ops ds3231_rtc_ops = {
 272         .get = ds3231_rtc_get,
 273         .set = ds3231_rtc_set,
 274         .reset = ds3231_rtc_reset,
 275 };
 276
 277 static const struct udevice_id ds3231_rtc_ids[] = {
 278         { .compatible = "dallas,ds3231" },
 279         { .compatible = "dallas,ds3232" },
 280         { }
 281 };
 282
 283 U_BOOT_DRIVER(rtc_ds3231) = {
 284         .name   = "rtc-ds3231",
 285         .id     = UCLASS_RTC,
 286         .probe  = ds3231_probe,
 287         .of_match = ds3231_rtc_ids,
 288         .ops    = &ds3231_rtc_ops,
 289 };
 290 #endif