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 #include <linux/delay.h>
18
19 #ifndef CONFIG_SYS_I2C_RTC_ADDR
20 #define CONFIG_SYS_I2C_RTC_ADDR 0x50
21 #endif
22
23 /* ------------------------------------------------------------------------- */
24
rtc_read(uchar reg)25 static uchar rtc_read (uchar reg)
26 {
27 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
28 }
29
rtc_write(uchar reg,uchar val)30 static void rtc_write (uchar reg, uchar val)
31 {
32 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
33 udelay(2500);
34 }
35
36 /* ------------------------------------------------------------------------- */
37
rtc_get(struct rtc_time * tmp)38 int rtc_get (struct rtc_time *tmp)
39 {
40 uchar sec, min, hour, mday, wday, mon, cent, year;
41 int retry = 1;
42
43 do {
44 sec = rtc_read (0x80);
45 min = rtc_read (0x82);
46 hour = rtc_read (0x84);
47 mday = rtc_read (0x86);
48 mon = rtc_read (0x88);
49 wday = rtc_read (0x8a);
50 year = rtc_read (0x8c);
51 cent = rtc_read (0x92);
52 /*
53 * Check for seconds rollover
54 */
55 if ((sec != 59) || (rtc_read(0x80) == sec)){
56 retry = 0;
57 }
58 } while (retry);
59
60 debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x "
61 "hr: %02x min: %02x sec: %02x\n",
62 year, mon, cent, mday, wday,
63 hour, min, sec );
64
65 tmp->tm_sec = bcd2bin (sec & 0x7F);
66 tmp->tm_min = bcd2bin (min & 0x7F);
67 tmp->tm_hour = bcd2bin (hour & 0x3F);
68 tmp->tm_mday = bcd2bin (mday & 0x3F);
69 tmp->tm_mon = bcd2bin (mon & 0x1F);
70 tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100;
71 tmp->tm_wday = bcd2bin (wday & 0x07);
72 tmp->tm_yday = 0;
73 tmp->tm_isdst= 0;
74
75 debug ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
76 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
77 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
78
79 return 0;
80 }
81
rtc_set(struct rtc_time * tmp)82 int rtc_set (struct rtc_time *tmp)
83 {
84
85 debug ( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
86 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
87 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
88
89 rtc_write (0x9E, 0x00);
90 rtc_write (0x80, 0); /* Clear seconds to ensure no rollover */
91 rtc_write (0x92, bin2bcd(tmp->tm_year / 100));
92 rtc_write (0x8c, bin2bcd(tmp->tm_year % 100));
93 rtc_write (0x8a, bin2bcd(tmp->tm_wday));
94 rtc_write (0x88, bin2bcd(tmp->tm_mon));
95 rtc_write (0x86, bin2bcd(tmp->tm_mday));
96 rtc_write (0x84, bin2bcd(tmp->tm_hour));
97 rtc_write (0x82, bin2bcd(tmp->tm_min ));
98 rtc_write (0x80, bin2bcd(tmp->tm_sec ));
99
100 return 0;
101 }
102
rtc_reset(void)103 void rtc_reset (void)
104 {
105 }
106