1 // SPDX-License-Identifier: GPL-2.0+
4 * Stefan Roese, DENX Software Engineering, sr@denx.de.
6 * based on a the Linux rtc-m41t80.c driver which is:
7 * Alexander Bigga <ab@mycable.de>, 2006 (c) mycable GmbH
11 * Date & Time support for STMicroelectronics M41T62
21 #define M41T62_REG_SSEC 0
22 #define M41T62_REG_SEC 1
23 #define M41T62_REG_MIN 2
24 #define M41T62_REG_HOUR 3
25 #define M41T62_REG_WDAY 4
26 #define M41T62_REG_DAY 5
27 #define M41T62_REG_MON 6
28 #define M41T62_REG_YEAR 7
29 #define M41T62_REG_ALARM_MON 0xa
30 #define M41T62_REG_ALARM_DAY 0xb
31 #define M41T62_REG_ALARM_HOUR 0xc
32 #define M41T62_REG_ALARM_MIN 0xd
33 #define M41T62_REG_ALARM_SEC 0xe
34 #define M41T62_REG_FLAGS 0xf
36 #define M41T62_DATETIME_REG_SIZE (M41T62_REG_YEAR + 1)
37 #define M41T62_ALARM_REG_SIZE \
38 (M41T62_REG_ALARM_SEC + 1 - M41T62_REG_ALARM_MON)
40 #define M41T62_SEC_ST (1 << 7) /* ST: Stop Bit */
41 #define M41T62_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
42 #define M41T62_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
43 #define M41T62_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
44 #define M41T62_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
45 #define M41T62_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
47 #define M41T62_FEATURE_HT (1 << 0)
48 #define M41T62_FEATURE_BL (1 << 1)
50 #define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
52 static void m41t62_update_rtc_time(struct rtc_time *tm, u8 *buf)
54 debug("%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
55 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
57 buf[0], buf[1], buf[2], buf[3],
58 buf[4], buf[5], buf[6], buf[7]);
60 tm->tm_sec = bcd2bin(buf[M41T62_REG_SEC] & 0x7f);
61 tm->tm_min = bcd2bin(buf[M41T62_REG_MIN] & 0x7f);
62 tm->tm_hour = bcd2bin(buf[M41T62_REG_HOUR] & 0x3f);
63 tm->tm_mday = bcd2bin(buf[M41T62_REG_DAY] & 0x3f);
64 tm->tm_wday = buf[M41T62_REG_WDAY] & 0x07;
65 tm->tm_mon = bcd2bin(buf[M41T62_REG_MON] & 0x1f);
67 /* assume 20YY not 19YY, and ignore the Century Bit */
68 /* U-Boot needs to add 1900 here */
69 tm->tm_year = bcd2bin(buf[M41T62_REG_YEAR]) + 100 + 1900;
71 debug("%s: tm is secs=%d, mins=%d, hours=%d, "
72 "mday=%d, mon=%d, year=%d, wday=%d\n",
74 tm->tm_sec, tm->tm_min, tm->tm_hour,
75 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
78 static void m41t62_set_rtc_buf(const struct rtc_time *tm, u8 *buf)
80 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
81 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
82 tm->tm_hour, tm->tm_min, tm->tm_sec);
84 /* Merge time-data and register flags into buf[0..7] */
85 buf[M41T62_REG_SSEC] = 0;
87 bin2bcd(tm->tm_sec) | (buf[M41T62_REG_SEC] & ~0x7f);
89 bin2bcd(tm->tm_min) | (buf[M41T62_REG_MIN] & ~0x7f);
90 buf[M41T62_REG_HOUR] =
91 bin2bcd(tm->tm_hour) | (buf[M41T62_REG_HOUR] & ~0x3f) ;
92 buf[M41T62_REG_WDAY] =
93 (tm->tm_wday & 0x07) | (buf[M41T62_REG_WDAY] & ~0x07);
95 bin2bcd(tm->tm_mday) | (buf[M41T62_REG_DAY] & ~0x3f);
97 bin2bcd(tm->tm_mon) | (buf[M41T62_REG_MON] & ~0x1f);
98 /* assume 20YY not 19YY */
99 buf[M41T62_REG_YEAR] = bin2bcd(tm->tm_year % 100);
102 int rtc_get(struct rtc_time *tm)
104 u8 buf[M41T62_DATETIME_REG_SIZE];
106 i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
107 m41t62_update_rtc_time(tm, buf);
112 int rtc_set(struct rtc_time *tm)
114 u8 buf[M41T62_DATETIME_REG_SIZE];
116 i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
117 m41t62_set_rtc_buf(tm, buf);
119 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf,
120 M41T62_DATETIME_REG_SIZE)) {
121 printf("I2C write failed in %s()\n", __func__);
133 * M41T82: Make sure HT (Halt Update) bit is cleared.
134 * This bit is 0 in M41T62 so its save to clear it always.
136 i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T62_REG_ALARM_HOUR, 1, &val, 1);
137 val &= ~M41T80_ALHOUR_HT;
138 i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T62_REG_ALARM_HOUR, 1, &val, 1);