xref: /openbmc/u-boot/drivers/rtc/rs5c372.c (revision 0a21fdd6)
1 /*
2  * rs5c372.c
3  *
4  * Device driver for Ricoh's Real Time Controller RS5C372A.
5  *
6  * Copyright (C) 2004 Gary Jennejohn garyj@denx.de
7  *
8  * Based in part in ds1307.c -
9  * (C) Copyright 2001, 2002, 2003
10  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
11  * Keith Outwater, keith_outwater@mvis.com`
12  * Steven Scholz, steven.scholz@imc-berlin.de
13  *
14  * See file CREDITS for list of people who contributed to this
15  * project.
16  *
17  * This program is free software; you can redistribute it and/or modify
18  * it under the terms of the GNU General Public License version 2 as
19  * published by the Free Software Foundation.
20  */
21 
22 #include <common.h>
23 #include <command.h>
24 #include <rtc.h>
25 #include <i2c.h>
26 
27 /*
28  * Reads are always done starting with register 15, which requires some
29  * jumping-through-hoops to access the data correctly.
30  *
31  * Writes are always done starting with register 0.
32  */
33 
34 #define DEBUG 0
35 
36 #if DEBUG
37 static unsigned int rtc_debug = DEBUG;
38 #else
39 #define rtc_debug 0	/* gcc will remove all the debug code for us */
40 #endif
41 
42 #ifndef CONFIG_SYS_I2C_RTC_ADDR
43 #define CONFIG_SYS_I2C_RTC_ADDR 0x32
44 #endif
45 
46 #define RS5C372_RAM_SIZE 0x10
47 #define RATE_32000HZ	0x80	/* Rate Select 32.000KHz */
48 #define RATE_32768HZ	0x00	/* Rate Select 32.768KHz */
49 
50 #define STATUS_XPT  0x10    /* data invalid because voltage was 0 */
51 
52 #define USE_24HOUR_MODE 0x20
53 #define TWELVE_HOUR_MODE(n) ((((n) >> 5) & 1) == 0)
54 #define HOURS_AP(n)	(((n) >> 5) & 1)
55 #define HOURS_12(n)	bcd2bin((n) & 0x1F)
56 #define HOURS_24(n)	bcd2bin((n) & 0x3F)
57 
58 
59 static int setup_done = 0;
60 
61 static int
62 rs5c372_readram(unsigned char *buf, int len)
63 {
64 	int ret;
65 
66 	ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, len);
67 	if (ret != 0) {
68 		printf("%s: failed to read\n", __FUNCTION__);
69 		return ret;
70 	}
71 
72 	if (buf[0] & STATUS_XPT)
73 		printf("### Warning: RTC lost power\n");
74 
75 	return ret;
76 }
77 
78 static void
79 rs5c372_enable(void)
80 {
81 	unsigned char buf[RS5C372_RAM_SIZE + 1];
82 	int ret;
83 
84 	/* note that this returns reg. 15 in buf[1] */
85 	ret = rs5c372_readram(&buf[1], RS5C372_RAM_SIZE);
86 	if (ret != 0) {
87 		printf("%s: failed\n", __FUNCTION__);
88 		return;
89 	}
90 
91 	buf[0] = 0;
92 	/* we want to start writing at register 0 so we have to copy the */
93 	/* register contents up one slot */
94 	for (ret = 2; ret < 9; ret++)
95 		buf[ret - 1] = buf[ret];
96 	/* registers 0 to 6 (time values) are not touched */
97 	buf[8] = RATE_32768HZ; /* reg. 7 */
98 	buf[9] = 0; /* reg. 8 */
99 	buf[10] = 0; /* reg. 9 */
100 	buf[11] = 0; /* reg. 10 */
101 	buf[12] = 0; /* reg. 11 */
102 	buf[13] = 0; /* reg. 12 */
103 	buf[14] = 0; /* reg. 13 */
104 	buf[15] = 0; /* reg. 14 */
105 	buf[16] = USE_24HOUR_MODE; /* reg. 15 */
106 	ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, RS5C372_RAM_SIZE+1);
107 	if (ret != 0) {
108 		printf("%s: failed\n", __FUNCTION__);
109 		return;
110 	}
111 	setup_done = 1;
112 
113 	return;
114 }
115 
116 static void
117 rs5c372_convert_to_time(struct rtc_time *dt, unsigned char *buf)
118 {
119 	/* buf[0] is register 15 */
120 	dt->tm_sec = bcd2bin(buf[1]);
121 	dt->tm_min = bcd2bin(buf[2]);
122 
123 	if (TWELVE_HOUR_MODE(buf[0])) {
124 		dt->tm_hour = HOURS_12(buf[3]);
125 		if (HOURS_AP(buf[3])) /* PM */
126 			dt->tm_hour += 12;
127 	} else /* 24-hour-mode */
128 		dt->tm_hour = HOURS_24(buf[3]);
129 
130 	dt->tm_mday = bcd2bin(buf[5]);
131 	dt->tm_mon = bcd2bin(buf[6]);
132 	dt->tm_year = bcd2bin(buf[7]);
133 	if (dt->tm_year >= 70)
134 		dt->tm_year += 1900;
135 	else
136 		dt->tm_year += 2000;
137 	/* 0 is Sunday */
138 	dt->tm_wday = bcd2bin(buf[4] & 0x07);
139 	dt->tm_yday = 0;
140 	dt->tm_isdst= 0;
141 
142 	if(rtc_debug > 2) {
143 		printf("rs5c372_convert_to_time: year = %d\n", dt->tm_year);
144 		printf("rs5c372_convert_to_time: mon  = %d\n", dt->tm_mon);
145 		printf("rs5c372_convert_to_time: mday = %d\n", dt->tm_mday);
146 		printf("rs5c372_convert_to_time: hour = %d\n", dt->tm_hour);
147 		printf("rs5c372_convert_to_time: min  = %d\n", dt->tm_min);
148 		printf("rs5c372_convert_to_time: sec  = %d\n", dt->tm_sec);
149 	}
150 }
151 
152 /*
153  * Get the current time from the RTC
154  */
155 int
156 rtc_get (struct rtc_time *tmp)
157 {
158 	unsigned char buf[RS5C372_RAM_SIZE];
159 	int ret;
160 
161 	if (!setup_done)
162 		rs5c372_enable();
163 
164 	if (!setup_done)
165 		return -1;
166 
167 	memset(buf, 0, sizeof(buf));
168 
169 	/* note that this returns reg. 15 in buf[0] */
170 	ret = rs5c372_readram(buf, RS5C372_RAM_SIZE);
171 	if (ret != 0) {
172 		printf("%s: failed\n", __FUNCTION__);
173 		return -1;
174 	}
175 
176 	rs5c372_convert_to_time(tmp, buf);
177 
178 	return 0;
179 }
180 
181 /*
182  * Set the RTC
183  */
184 int rtc_set (struct rtc_time *tmp)
185 {
186 	unsigned char buf[8], reg15;
187 	int ret;
188 
189 	if (!setup_done)
190 		rs5c372_enable();
191 
192 	if (!setup_done)
193 		return -1;
194 
195 	if(rtc_debug > 2) {
196 		printf("rtc_set: tm_year = %d\n", tmp->tm_year);
197 		printf("rtc_set: tm_mon	 = %d\n", tmp->tm_mon);
198 		printf("rtc_set: tm_mday = %d\n", tmp->tm_mday);
199 		printf("rtc_set: tm_hour = %d\n", tmp->tm_hour);
200 		printf("rtc_set: tm_min	 = %d\n", tmp->tm_min);
201 		printf("rtc_set: tm_sec	 = %d\n", tmp->tm_sec);
202 	}
203 
204 	memset(buf, 0, sizeof(buf));
205 
206 	/* only read register 15 */
207 	ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, 1);
208 
209 	if (ret == 0) {
210 		/* need to save register 15 */
211 		reg15 = buf[0];
212 		buf[0] = 0;	/* register address on RS5C372 */
213 		buf[1] = bin2bcd(tmp->tm_sec);
214 		buf[2] = bin2bcd(tmp->tm_min);
215 		/* need to handle 12 hour mode */
216 		if (TWELVE_HOUR_MODE(reg15)) {
217 			if (tmp->tm_hour >= 12) { /* PM */
218 				/* 12 PM is a special case */
219 				if (tmp->tm_hour == 12)
220 					buf[3] = bin2bcd(tmp->tm_hour);
221 				else
222 					buf[3] = bin2bcd(tmp->tm_hour - 12);
223 				buf[3] |= 0x20;
224 			}
225 		} else {
226 			buf[3] = bin2bcd(tmp->tm_hour);
227 		}
228 
229 		buf[4] = bin2bcd(tmp->tm_wday);
230 		buf[5] = bin2bcd(tmp->tm_mday);
231 		buf[6] = bin2bcd(tmp->tm_mon);
232 		if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
233 			printf("WARNING: year should be between 1970 and 2069!\n");
234 		buf[7] = bin2bcd(tmp->tm_year % 100);
235 
236 		ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, 8);
237 		if (ret != 0) {
238 			printf("rs5c372_set_datetime(), i2c_master_send() returned %d\n",ret);
239 			return -1;
240 		}
241 	} else {
242 		return -1;
243 	}
244 
245 	return 0;
246 }
247 
248 /*
249  * Reset the RTC.
250  */
251 void
252 rtc_reset (void)
253 {
254 	if (!setup_done)
255 		rs5c372_enable();
256 }
257