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Larry Johnson12618272007-12-22 15:14:00 -05001/*
2 * (C) Copyright 2007
3 * Larry Johnson, lrj@acm.org
4 *
5 * based on rtc/m41t11.c which is ...
6 *
7 * (C) Copyright 2002
8 * Andrew May, Viasat Inc, amay@viasat.com
9 *
Wolfgang Denk1a459662013-07-08 09:37:19 +020010 * SPDX-License-Identifier: GPL-2.0+
Larry Johnson12618272007-12-22 15:14:00 -050011 */
12
13/*
14 * STMicroelectronics M41T60 serial access real-time clock
15 */
16
17/* #define DEBUG 1 */
18
19#include <common.h>
20#include <command.h>
21#include <rtc.h>
22#include <i2c.h>
23
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +020024#if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
Larry Johnson12618272007-12-22 15:14:00 -050025
Larry Johnson12618272007-12-22 15:14:00 -050026/*
27 * Convert between century and "century bits" (CB1 and CB0). These routines
28 * assume years are in the range 1900 - 2299.
29 */
30
31static unsigned char year2cb(unsigned const year)
32{
33 if (year < 1900 || year >= 2300)
34 printf("M41T60 RTC: year %d out of range\n", year);
35
36 return (year / 100) & 0x3;
37}
38
39static unsigned cb2year(unsigned const cb)
40{
41 return 1900 + 100 * ((cb + 1) & 0x3);
42}
43
44/*
45 * These are simple defines for the chip local to here so they aren't too
46 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet.
47 */
48#define RTC_SEC 0x0
49#define RTC_MIN 0x1
50#define RTC_HOUR 0x2
51#define RTC_DAY 0x3
52#define RTC_DATE 0x4
53#define RTC_MONTH 0x5
54#define RTC_YEAR 0x6
55
56#define RTC_REG_CNT 7
57
58#define RTC_CTRL 0x7
59
60#if defined(DEBUG)
61static void rtc_dump(char const *const label)
62{
63 uchar data[8];
64
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +020065 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
Larry Johnson12618272007-12-22 15:14:00 -050066 printf("I2C read failed in rtc_dump()\n");
67 return;
68 }
69 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n",
70 label, data[0], data[1], data[2], data[3],
71 data[4], data[5], data[6], data[7]);
72}
73#else
74#define rtc_dump(label)
75#endif
76
77static uchar *rtc_validate(void)
78{
79 /*
80 * This routine uses the OUT bit and the validity of the time values to
81 * determine whether there has been an initial power-up since the last
82 * time the routine was run. It assumes that the OUT bit is not being
83 * used for any other purpose.
84 */
85 static const uchar daysInMonth[0x13] = {
86 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31,
87 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
88 0x31, 0x30, 0x31
89 };
90 static uchar data[8];
91 uchar min, date, month, years;
92
93 rtc_dump("begin validate");
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +020094 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
Larry Johnson12618272007-12-22 15:14:00 -050095 printf("I2C read failed in rtc_validate()\n");
96 return 0;
97 }
98 /*
99 * If the OUT bit is "1", there has been a loss of power, so stop the
100 * oscillator so it can be "kick-started" as per data sheet.
101 */
102 if (0x00 != (data[RTC_CTRL] & 0x80)) {
103 printf("M41T60 RTC clock lost power.\n");
104 data[RTC_SEC] = 0x80;
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200105 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) {
Larry Johnson12618272007-12-22 15:14:00 -0500106 printf("I2C write failed in rtc_validate()\n");
107 return 0;
108 }
109 }
110 /*
111 * If the oscillator is stopped or the date is invalid, then reset the
112 * OUT bit to "0", reset the date registers, and start the oscillator.
113 */
114 min = data[RTC_MIN] & 0x7F;
115 date = data[RTC_DATE];
116 month = data[RTC_MONTH] & 0x3F;
117 years = data[RTC_YEAR];
118 if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) ||
119 0x59 < min || 0x09 < (min & 0x0F) ||
120 0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) ||
121 0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] ||
122 0x12 < month ||
123 0x99 < years || 0x09 < (years & 0x0F) ||
124 daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date ||
125 (0x29 == date && 0x02 == month &&
126 ((0x00 != (years & 0x03)) ||
127 (0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) {
128 printf("Resetting M41T60 RTC clock.\n");
129 /*
130 * Set to 00:00:00 1900-01-01 (Monday)
131 */
132 data[RTC_SEC] = 0x00;
133 data[RTC_MIN] &= 0x80; /* preserve OFIE bit */
134 data[RTC_HOUR] = 0x00;
135 data[RTC_DAY] = 0x02;
136 data[RTC_DATE] = 0x01;
137 data[RTC_MONTH] = 0xC1;
138 data[RTC_YEAR] = 0x00;
139 data[RTC_CTRL] &= 0x7F; /* reset OUT bit */
140
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200141 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
Larry Johnson12618272007-12-22 15:14:00 -0500142 printf("I2C write failed in rtc_validate()\n");
143 return 0;
144 }
145 }
146 return data;
147}
148
Yuri Tikhonovb73a19e2008-03-20 17:56:04 +0300149int rtc_get(struct rtc_time *tmp)
Larry Johnson12618272007-12-22 15:14:00 -0500150{
151 uchar const *const data = rtc_validate();
152
153 if (!data)
Yuri Tikhonovb73a19e2008-03-20 17:56:04 +0300154 return -1;
Larry Johnson12618272007-12-22 15:14:00 -0500155
156 tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F);
157 tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F);
158 tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F);
159 tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F);
160 tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F);
161 tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]);
162 tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1;
163 tmp->tm_yday = 0;
164 tmp->tm_isdst = 0;
165
166 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
167 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
168 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
Yuri Tikhonovb73a19e2008-03-20 17:56:04 +0300169
170 return 0;
Larry Johnson12618272007-12-22 15:14:00 -0500171}
172
Jean-Christophe PLAGNIOL-VILLARDd1e23192008-09-01 23:06:23 +0200173int rtc_set(struct rtc_time *tmp)
Larry Johnson12618272007-12-22 15:14:00 -0500174{
175 uchar *const data = rtc_validate();
176
177 if (!data)
Jean-Christophe PLAGNIOL-VILLARDd1e23192008-09-01 23:06:23 +0200178 return -1;
Larry Johnson12618272007-12-22 15:14:00 -0500179
180 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
181 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
182 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
183
184 data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F);
185 data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F);
186 data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F;
187 data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F;
188 data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F;
189 data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100);
190 data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6;
191 data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07;
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200192 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) {
Larry Johnson12618272007-12-22 15:14:00 -0500193 printf("I2C write failed in rtc_set()\n");
Jean-Christophe PLAGNIOL-VILLARDd1e23192008-09-01 23:06:23 +0200194 return -1;
Larry Johnson12618272007-12-22 15:14:00 -0500195 }
Jean-Christophe PLAGNIOL-VILLARDd1e23192008-09-01 23:06:23 +0200196
197 return 0;
Larry Johnson12618272007-12-22 15:14:00 -0500198}
199
200void rtc_reset(void)
201{
202 uchar *const data = rtc_validate();
Simon Glass00caae62017-08-03 12:22:12 -0600203 char const *const s = env_get("rtccal");
Larry Johnson12618272007-12-22 15:14:00 -0500204
205 if (!data)
206 return;
207
208 rtc_dump("begin reset");
209 /*
210 * If environmental variable "rtccal" is present, it must be a hex value
211 * between 0x00 and 0x3F, inclusive. The five least-significan bits
212 * represent the calibration magnitude, and the sixth bit the sign bit.
213 * If these do not match the contents of the hardware register, that
214 * register is updated. The value 0x00 imples no correction. Consult
215 * the M41T60 documentation for further details.
216 */
217 if (s) {
218 unsigned long const l = simple_strtoul(s, 0, 16);
219
220 if (l <= 0x3F) {
221 if ((data[RTC_CTRL] & 0x3F) != l) {
Stefan Roese10943c92008-07-10 10:00:45 +0200222 printf("Setting RTC calibration to 0x%02lX\n",
Larry Johnson12618272007-12-22 15:14:00 -0500223 l);
224 data[RTC_CTRL] &= 0xC0;
225 data[RTC_CTRL] |= (uchar) l;
226 }
227 } else
228 printf("environment parameter \"rtccal\" not valid: "
229 "ignoring\n");
230 }
231 /*
232 * Turn off frequency test.
233 */
234 data[RTC_CTRL] &= 0xBF;
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200235 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) {
Larry Johnson12618272007-12-22 15:14:00 -0500236 printf("I2C write failed in rtc_reset()\n");
237 return;
238 }
239 rtc_dump("end reset");
240}
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200241#endif /* CONFIG_RTC_M41T60 && CONFIG_SYS_I2C_RTC_ADDR && CONFIG_CMD_DATE */