ds3231.c
4.35 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/*
* (C) Copyright 2006
* Markus Klotzbuecher, mk@denx.de
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
* Extremly Accurate DS3231 Real Time Clock (RTC).
*
* copied from ds1337.c
*/
#include <common.h>
#include <command.h>
#include <rtc.h>
#include <i2c.h>
#if defined(CONFIG_CMD_DATE)
/*
* RTC register addresses
*/
#define RTC_SEC_REG_ADDR 0x0
#define RTC_MIN_REG_ADDR 0x1
#define RTC_HR_REG_ADDR 0x2
#define RTC_DAY_REG_ADDR 0x3
#define RTC_DATE_REG_ADDR 0x4
#define RTC_MON_REG_ADDR 0x5
#define RTC_YR_REG_ADDR 0x6
#define RTC_CTL_REG_ADDR 0x0e
#define RTC_STAT_REG_ADDR 0x0f
/*
* RTC control register bits
*/
#define RTC_CTL_BIT_A1IE 0x1 /* Alarm 1 interrupt enable */
#define RTC_CTL_BIT_A2IE 0x2 /* Alarm 2 interrupt enable */
#define RTC_CTL_BIT_INTCN 0x4 /* Interrupt control */
#define RTC_CTL_BIT_RS1 0x8 /* Rate select 1 */
#define RTC_CTL_BIT_RS2 0x10 /* Rate select 2 */
#define RTC_CTL_BIT_DOSC 0x80 /* Disable Oscillator */
/*
* RTC status register bits
*/
#define RTC_STAT_BIT_A1F 0x1 /* Alarm 1 flag */
#define RTC_STAT_BIT_A2F 0x2 /* Alarm 2 flag */
#define RTC_STAT_BIT_OSF 0x80 /* Oscillator stop flag */
#define RTC_STAT_BIT_BB32KHZ 0x40 /* Battery backed 32KHz Output */
#define RTC_STAT_BIT_EN32KHZ 0x8 /* Enable 32KHz Output */
static uchar rtc_read (uchar reg);
static void rtc_write (uchar reg, uchar val);
/*
* Get the current time from the RTC
*/
int rtc_get (struct rtc_time *tmp)
{
int rel = 0;
uchar sec, min, hour, mday, wday, mon_cent, year, control, status;
control = rtc_read (RTC_CTL_REG_ADDR);
status = rtc_read (RTC_STAT_REG_ADDR);
sec = rtc_read (RTC_SEC_REG_ADDR);
min = rtc_read (RTC_MIN_REG_ADDR);
hour = rtc_read (RTC_HR_REG_ADDR);
wday = rtc_read (RTC_DAY_REG_ADDR);
mday = rtc_read (RTC_DATE_REG_ADDR);
mon_cent = rtc_read (RTC_MON_REG_ADDR);
year = rtc_read (RTC_YR_REG_ADDR);
debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
"hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
year, mon_cent, mday, wday, hour, min, sec, control, status);
if (status & RTC_STAT_BIT_OSF) {
printf ("### Warning: RTC oscillator has stopped\n");
/* clear the OSF flag */
rtc_write (RTC_STAT_REG_ADDR,
rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
rel = -1;
}
tmp->tm_sec = bcd2bin (sec & 0x7F);
tmp->tm_min = bcd2bin (min & 0x7F);
tmp->tm_hour = bcd2bin (hour & 0x3F);
tmp->tm_mday = bcd2bin (mday & 0x3F);
tmp->tm_mon = bcd2bin (mon_cent & 0x1F);
tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
tmp->tm_yday = 0;
tmp->tm_isdst= 0;
debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
return rel;
}
/*
* Set the RTC
*/
int rtc_set (struct rtc_time *tmp)
{
uchar century;
debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
century = (tmp->tm_year >= 2000) ? 0x80 : 0;
rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);
rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
return 0;
}
/*
* Reset the RTC. We also enable the oscillator output on the
* SQW/INTB* pin and program it for 32,768 Hz output. Note that
* according to the datasheet, turning on the square wave output
* increases the current drain on the backup battery from about
* 600 nA to 2uA.
*/
void rtc_reset (void)
{
rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
}
/*
* Enable 32KHz output
*/
void rtc_enable_32khz_output(void)
{
rtc_write(RTC_STAT_REG_ADDR,
RTC_STAT_BIT_BB32KHZ | RTC_STAT_BIT_EN32KHZ);
}
/*
* Helper functions
*/
static
uchar rtc_read (uchar reg)
{
return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
}
static void rtc_write (uchar reg, uchar val)
{
i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
}
#endif