xref: /openbmc/u-boot/drivers/rtc/m41t62.c (revision efc05ae1)
1 /*
2  * (C) Copyright 2008
3  * Stefan Roese, DENX Software Engineering, sr@denx.de.
4  *
5  * based on a the Linux rtc-m41t80.c driver which is:
6  *   Alexander Bigga <ab@mycable.de>, 2006 (c) mycable GmbH
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21  * MA 02111-1307 USA
22  */
23 
24 /*
25  * Date & Time support for STMicroelectronics M41T62
26  */
27 
28 /* #define	DEBUG	*/
29 
30 #include <common.h>
31 #include <command.h>
32 #include <rtc.h>
33 #include <i2c.h>
34 
35 #if defined(CONFIG_CMD_DATE)
36 
37 #define M41T62_REG_SSEC	0
38 #define M41T62_REG_SEC	1
39 #define M41T62_REG_MIN	2
40 #define M41T62_REG_HOUR	3
41 #define M41T62_REG_WDAY	4
42 #define M41T62_REG_DAY	5
43 #define M41T62_REG_MON	6
44 #define M41T62_REG_YEAR	7
45 #define M41T62_REG_ALARM_MON	0xa
46 #define M41T62_REG_ALARM_DAY	0xb
47 #define M41T62_REG_ALARM_HOUR	0xc
48 #define M41T62_REG_ALARM_MIN	0xd
49 #define M41T62_REG_ALARM_SEC	0xe
50 #define M41T62_REG_FLAGS	0xf
51 
52 #define M41T62_DATETIME_REG_SIZE	(M41T62_REG_YEAR + 1)
53 #define M41T62_ALARM_REG_SIZE	\
54 	(M41T62_REG_ALARM_SEC + 1 - M41T62_REG_ALARM_MON)
55 
56 #define M41T62_SEC_ST		(1 << 7)	/* ST: Stop Bit */
57 #define M41T62_ALMON_AFE	(1 << 7)	/* AFE: AF Enable Bit */
58 #define M41T62_ALMON_SQWE	(1 << 6)	/* SQWE: SQW Enable Bit */
59 #define M41T62_ALHOUR_HT	(1 << 6)	/* HT: Halt Update Bit */
60 #define M41T62_FLAGS_AF		(1 << 6)	/* AF: Alarm Flag Bit */
61 #define M41T62_FLAGS_BATT_LOW	(1 << 4)	/* BL: Battery Low Bit */
62 
63 #define M41T62_FEATURE_HT	(1 << 0)
64 #define M41T62_FEATURE_BL	(1 << 1)
65 
66 int rtc_get(struct rtc_time *tm)
67 {
68 	u8 buf[M41T62_DATETIME_REG_SIZE];
69 
70 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
71 
72 	debug("%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
73 	      "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
74 	      __FUNCTION__,
75 	      buf[0], buf[1], buf[2], buf[3],
76 	      buf[4], buf[5], buf[6], buf[7]);
77 
78 	tm->tm_sec = bcd2bin(buf[M41T62_REG_SEC] & 0x7f);
79 	tm->tm_min = bcd2bin(buf[M41T62_REG_MIN] & 0x7f);
80 	tm->tm_hour = bcd2bin(buf[M41T62_REG_HOUR] & 0x3f);
81 	tm->tm_mday = bcd2bin(buf[M41T62_REG_DAY] & 0x3f);
82 	tm->tm_wday = buf[M41T62_REG_WDAY] & 0x07;
83 	tm->tm_mon = bcd2bin(buf[M41T62_REG_MON] & 0x1f);
84 
85 	/* assume 20YY not 19YY, and ignore the Century Bit */
86 	/* U-Boot needs to add 1900 here */
87 	tm->tm_year = bcd2bin(buf[M41T62_REG_YEAR]) + 100 + 1900;
88 
89 	debug("%s: tm is secs=%d, mins=%d, hours=%d, "
90 	      "mday=%d, mon=%d, year=%d, wday=%d\n",
91 	      __FUNCTION__,
92 	      tm->tm_sec, tm->tm_min, tm->tm_hour,
93 	      tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
94 
95 	return 0;
96 }
97 
98 int rtc_set(struct rtc_time *tm)
99 {
100 	u8 buf[M41T62_DATETIME_REG_SIZE];
101 
102 	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
103 	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
104 	      tm->tm_hour, tm->tm_min, tm->tm_sec);
105 
106 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
107 
108 	/* Merge time-data and register flags into buf[0..7] */
109 	buf[M41T62_REG_SSEC] = 0;
110 	buf[M41T62_REG_SEC] =
111 		bin2bcd(tm->tm_sec) | (buf[M41T62_REG_SEC] & ~0x7f);
112 	buf[M41T62_REG_MIN] =
113 		bin2bcd(tm->tm_min) | (buf[M41T62_REG_MIN] & ~0x7f);
114 	buf[M41T62_REG_HOUR] =
115 		bin2bcd(tm->tm_hour) | (buf[M41T62_REG_HOUR] & ~0x3f) ;
116 	buf[M41T62_REG_WDAY] =
117 		(tm->tm_wday & 0x07) | (buf[M41T62_REG_WDAY] & ~0x07);
118 	buf[M41T62_REG_DAY] =
119 		bin2bcd(tm->tm_mday) | (buf[M41T62_REG_DAY] & ~0x3f);
120 	buf[M41T62_REG_MON] =
121 		bin2bcd(tm->tm_mon) | (buf[M41T62_REG_MON] & ~0x1f);
122 	/* assume 20YY not 19YY */
123 	buf[M41T62_REG_YEAR] = bin2bcd(tm->tm_year % 100);
124 
125 	if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE)) {
126 		printf("I2C write failed in %s()\n", __func__);
127 		return -1;
128 	}
129 
130 	return 0;
131 }
132 
133 void rtc_reset(void)
134 {
135 	/*
136 	 * Nothing to do
137 	 */
138 }
139 
140 #endif
141