1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2004
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 */
6
7 /*
8 * Date & Time support for MAXIM MAX6900 RTC
9 */
10
11 /* #define DEBUG */
12
13 #include <common.h>
14 #include <command.h>
15 #include <rtc.h>
16 #include <i2c.h>
17
18 #ifndef CONFIG_SYS_I2C_RTC_ADDR
19 #define CONFIG_SYS_I2C_RTC_ADDR 0x50
20 #endif
21
22 /* ------------------------------------------------------------------------- */
23
rtc_read(uchar reg)24 static uchar rtc_read (uchar reg)
25 {
26 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
27 }
28
rtc_write(uchar reg,uchar val)29 static void rtc_write (uchar reg, uchar val)
30 {
31 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
32 udelay(2500);
33 }
34
35 /* ------------------------------------------------------------------------- */
36
rtc_get(struct rtc_time * tmp)37 int rtc_get (struct rtc_time *tmp)
38 {
39 uchar sec, min, hour, mday, wday, mon, cent, year;
40 int retry = 1;
41
42 do {
43 sec = rtc_read (0x80);
44 min = rtc_read (0x82);
45 hour = rtc_read (0x84);
46 mday = rtc_read (0x86);
47 mon = rtc_read (0x88);
48 wday = rtc_read (0x8a);
49 year = rtc_read (0x8c);
50 cent = rtc_read (0x92);
51 /*
52 * Check for seconds rollover
53 */
54 if ((sec != 59) || (rtc_read(0x80) == sec)){
55 retry = 0;
56 }
57 } while (retry);
58
59 debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x "
60 "hr: %02x min: %02x sec: %02x\n",
61 year, mon, cent, mday, wday,
62 hour, min, sec );
63
64 tmp->tm_sec = bcd2bin (sec & 0x7F);
65 tmp->tm_min = bcd2bin (min & 0x7F);
66 tmp->tm_hour = bcd2bin (hour & 0x3F);
67 tmp->tm_mday = bcd2bin (mday & 0x3F);
68 tmp->tm_mon = bcd2bin (mon & 0x1F);
69 tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100;
70 tmp->tm_wday = bcd2bin (wday & 0x07);
71 tmp->tm_yday = 0;
72 tmp->tm_isdst= 0;
73
74 debug ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
75 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
76 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
77
78 return 0;
79 }
80
rtc_set(struct rtc_time * tmp)81 int rtc_set (struct rtc_time *tmp)
82 {
83
84 debug ( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
85 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
86 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
87
88 rtc_write (0x9E, 0x00);
89 rtc_write (0x80, 0); /* Clear seconds to ensure no rollover */
90 rtc_write (0x92, bin2bcd(tmp->tm_year / 100));
91 rtc_write (0x8c, bin2bcd(tmp->tm_year % 100));
92 rtc_write (0x8a, bin2bcd(tmp->tm_wday));
93 rtc_write (0x88, bin2bcd(tmp->tm_mon));
94 rtc_write (0x86, bin2bcd(tmp->tm_mday));
95 rtc_write (0x84, bin2bcd(tmp->tm_hour));
96 rtc_write (0x82, bin2bcd(tmp->tm_min ));
97 rtc_write (0x80, bin2bcd(tmp->tm_sec ));
98
99 return 0;
100 }
101
rtc_reset(void)102 void rtc_reset (void)
103 {
104 }
105