1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2006
4 * Markus Klotzbuecher, mk@denx.de
5 */
6
7 /*
8 * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
9 * Extremly Accurate DS3231 Real Time Clock (RTC).
10 *
11 * copied from ds1337.c
12 */
13
14 #include <common.h>
15 #include <command.h>
16 #include <rtc.h>
17 #include <i2c.h>
18
19 #if defined(CONFIG_CMD_DATE)
20
21 /*
22 * RTC register addresses
23 */
24 #define RTC_SEC_REG_ADDR 0x0
25 #define RTC_MIN_REG_ADDR 0x1
26 #define RTC_HR_REG_ADDR 0x2
27 #define RTC_DAY_REG_ADDR 0x3
28 #define RTC_DATE_REG_ADDR 0x4
29 #define RTC_MON_REG_ADDR 0x5
30 #define RTC_YR_REG_ADDR 0x6
31 #define RTC_CTL_REG_ADDR 0x0e
32 #define RTC_STAT_REG_ADDR 0x0f
33
34
35 /*
36 * RTC control register bits
37 */
38 #define RTC_CTL_BIT_A1IE 0x1 /* Alarm 1 interrupt enable */
39 #define RTC_CTL_BIT_A2IE 0x2 /* Alarm 2 interrupt enable */
40 #define RTC_CTL_BIT_INTCN 0x4 /* Interrupt control */
41 #define RTC_CTL_BIT_RS1 0x8 /* Rate select 1 */
42 #define RTC_CTL_BIT_RS2 0x10 /* Rate select 2 */
43 #define RTC_CTL_BIT_DOSC 0x80 /* Disable Oscillator */
44
45 /*
46 * RTC status register bits
47 */
48 #define RTC_STAT_BIT_A1F 0x1 /* Alarm 1 flag */
49 #define RTC_STAT_BIT_A2F 0x2 /* Alarm 2 flag */
50 #define RTC_STAT_BIT_OSF 0x80 /* Oscillator stop flag */
51 #define RTC_STAT_BIT_BB32KHZ 0x40 /* Battery backed 32KHz Output */
52 #define RTC_STAT_BIT_EN32KHZ 0x8 /* Enable 32KHz Output */
53
54
55 static uchar rtc_read (uchar reg);
56 static void rtc_write (uchar reg, uchar val);
57
58
59 /*
60 * Get the current time from the RTC
61 */
rtc_get(struct rtc_time * tmp)62 int rtc_get (struct rtc_time *tmp)
63 {
64 int rel = 0;
65 uchar sec, min, hour, mday, wday, mon_cent, year, control, status;
66
67 control = rtc_read (RTC_CTL_REG_ADDR);
68 status = rtc_read (RTC_STAT_REG_ADDR);
69 sec = rtc_read (RTC_SEC_REG_ADDR);
70 min = rtc_read (RTC_MIN_REG_ADDR);
71 hour = rtc_read (RTC_HR_REG_ADDR);
72 wday = rtc_read (RTC_DAY_REG_ADDR);
73 mday = rtc_read (RTC_DATE_REG_ADDR);
74 mon_cent = rtc_read (RTC_MON_REG_ADDR);
75 year = rtc_read (RTC_YR_REG_ADDR);
76
77 debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
78 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
79 year, mon_cent, mday, wday, hour, min, sec, control, status);
80
81 if (status & RTC_STAT_BIT_OSF) {
82 printf ("### Warning: RTC oscillator has stopped\n");
83 /* clear the OSF flag */
84 rtc_write (RTC_STAT_REG_ADDR,
85 rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
86 rel = -1;
87 }
88
89 tmp->tm_sec = bcd2bin (sec & 0x7F);
90 tmp->tm_min = bcd2bin (min & 0x7F);
91 tmp->tm_hour = bcd2bin (hour & 0x3F);
92 tmp->tm_mday = bcd2bin (mday & 0x3F);
93 tmp->tm_mon = bcd2bin (mon_cent & 0x1F);
94 tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
95 tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
96 tmp->tm_yday = 0;
97 tmp->tm_isdst= 0;
98
99 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
100 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
101 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
102
103 return rel;
104 }
105
106
107 /*
108 * Set the RTC
109 */
rtc_set(struct rtc_time * tmp)110 int rtc_set (struct rtc_time *tmp)
111 {
112 uchar century;
113
114 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
115 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
116 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
117
118 rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
119
120 century = (tmp->tm_year >= 2000) ? 0x80 : 0;
121 rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);
122
123 rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
124 rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
125 rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
126 rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
127 rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
128
129 return 0;
130 }
131
132
133 /*
134 * Reset the RTC. We also enable the oscillator output on the
135 * SQW/INTB* pin and program it for 32,768 Hz output. Note that
136 * according to the datasheet, turning on the square wave output
137 * increases the current drain on the backup battery from about
138 * 600 nA to 2uA.
139 */
rtc_reset(void)140 void rtc_reset (void)
141 {
142 rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
143 }
144
145 /*
146 * Enable 32KHz output
147 */
rtc_enable_32khz_output(void)148 void rtc_enable_32khz_output(void)
149 {
150 rtc_write(RTC_STAT_REG_ADDR,
151 RTC_STAT_BIT_BB32KHZ | RTC_STAT_BIT_EN32KHZ);
152 }
153
154 /*
155 * Helper functions
156 */
157
158 static
rtc_read(uchar reg)159 uchar rtc_read (uchar reg)
160 {
161 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
162 }
163
164
rtc_write(uchar reg,uchar val)165 static void rtc_write (uchar reg, uchar val)
166 {
167 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
168 }
169
170 #endif
171