1 // SPDX-License-Identifier: GPL-2.0+
3 * (C) Copyright 2001, 2002, 2003
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 * Keith Outwater, keith_outwater@mvis.com`
6 * Steven Scholz, steven.scholz@imc-berlin.de
10 * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
11 * DS1307 and DS1338/9 Real Time Clock (RTC).
32 * RTC register addresses
34 #define RTC_SEC_REG_ADDR 0x00
35 #define RTC_MIN_REG_ADDR 0x01
36 #define RTC_HR_REG_ADDR 0x02
37 #define RTC_DAY_REG_ADDR 0x03
38 #define RTC_DATE_REG_ADDR 0x04
39 #define RTC_MON_REG_ADDR 0x05
40 #define RTC_YR_REG_ADDR 0x06
41 #define RTC_CTL_REG_ADDR 0x07
43 #define RTC_SEC_BIT_CH 0x80 /* Clock Halt (in Register 0) */
45 #define RTC_CTL_BIT_RS0 0x01 /* Rate select 0 */
46 #define RTC_CTL_BIT_RS1 0x02 /* Rate select 1 */
47 #define RTC_CTL_BIT_SQWE 0x10 /* Square Wave Enable */
48 #define RTC_CTL_BIT_OUT 0x80 /* Output Control */
50 /* MCP7941X-specific bits */
51 #define MCP7941X_BIT_ST 0x80
52 #define MCP7941X_BIT_VBATEN 0x08
56 /*---------------------------------------------------------------------*/
60 #define DEBUGR(fmt, args...) printf(fmt, ##args)
62 #define DEBUGR(fmt, args...)
64 /*---------------------------------------------------------------------*/
66 #ifndef CONFIG_SYS_I2C_RTC_ADDR
67 # define CONFIG_SYS_I2C_RTC_ADDR 0x68
70 #if defined(CONFIG_RTC_DS1307) && (CONFIG_SYS_I2C_SPEED > 100000)
71 # error The DS1307 is specified only up to 100kHz!
74 static uchar rtc_read (uchar reg);
75 static void rtc_write (uchar reg, uchar val);
78 * Get the current time from the RTC
80 int rtc_get (struct rtc_time *tmp)
83 uchar sec, min, hour, mday, wday, mon, year;
85 #ifdef CONFIG_RTC_MCP79411
88 sec = rtc_read (RTC_SEC_REG_ADDR);
89 min = rtc_read (RTC_MIN_REG_ADDR);
90 hour = rtc_read (RTC_HR_REG_ADDR);
91 wday = rtc_read (RTC_DAY_REG_ADDR);
92 mday = rtc_read (RTC_DATE_REG_ADDR);
93 mon = rtc_read (RTC_MON_REG_ADDR);
94 year = rtc_read (RTC_YR_REG_ADDR);
96 DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
97 "hr: %02x min: %02x sec: %02x\n",
98 year, mon, mday, wday, hour, min, sec);
100 #ifdef CONFIG_RTC_DS1307
101 if (sec & RTC_SEC_BIT_CH) {
102 printf ("### Warning: RTC oscillator has stopped\n");
103 /* clear the CH flag */
104 rtc_write (RTC_SEC_REG_ADDR,
105 rtc_read (RTC_SEC_REG_ADDR) & ~RTC_SEC_BIT_CH);
110 #ifdef CONFIG_RTC_MCP79411
111 /* make sure that the backup battery is enabled */
112 if (!(wday & MCP7941X_BIT_VBATEN)) {
113 rtc_write(RTC_DAY_REG_ADDR,
114 wday | MCP7941X_BIT_VBATEN);
117 /* clock halted? turn it on, so clock can tick. */
118 if (!(sec & MCP7941X_BIT_ST)) {
119 rtc_write(RTC_SEC_REG_ADDR, MCP7941X_BIT_ST);
120 printf("Started RTC\n");
126 tmp->tm_sec = bcd2bin (sec & 0x7F);
127 tmp->tm_min = bcd2bin (min & 0x7F);
128 tmp->tm_hour = bcd2bin (hour & 0x3F);
129 tmp->tm_mday = bcd2bin (mday & 0x3F);
130 tmp->tm_mon = bcd2bin (mon & 0x1F);
131 tmp->tm_year = bcd2bin (year) + ( bcd2bin (year) >= 70 ? 1900 : 2000);
132 tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
136 DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
137 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
138 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
147 int rtc_set (struct rtc_time *tmp)
149 DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
150 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
151 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
153 if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
154 printf("WARNING: year should be between 1970 and 2069!\n");
156 rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
157 rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
158 #ifdef CONFIG_RTC_MCP79411
159 rtc_write (RTC_DAY_REG_ADDR,
160 bin2bcd (tmp->tm_wday + 1) | MCP7941X_BIT_VBATEN);
162 rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
164 rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
165 rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
166 rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
167 #ifdef CONFIG_RTC_MCP79411
168 rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec) | MCP7941X_BIT_ST);
170 rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
178 * Reset the RTC. We setting the date back to 1970-01-01.
179 * We also enable the oscillator output on the SQW/OUT pin and program
180 * it for 32,768 Hz output. Note that according to the datasheet, turning
181 * on the square wave output increases the current drain on the backup
182 * battery to something between 480nA and 800nA.
184 void rtc_reset (void)
186 rtc_write (RTC_SEC_REG_ADDR, 0x00); /* clearing Clock Halt */
187 rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS0);
196 uchar rtc_read (uchar reg)
198 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
202 static void rtc_write (uchar reg, uchar val)
204 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
207 #endif /* !CONFIG_DM_RTC */
210 static int ds1307_rtc_set(struct udevice *dev, const struct rtc_time *tm)
214 enum ds_type type = dev_get_driver_data(dev);
216 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
217 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
218 tm->tm_hour, tm->tm_min, tm->tm_sec);
220 if (tm->tm_year < 1970 || tm->tm_year > 2069)
221 printf("WARNING: year should be between 1970 and 2069!\n");
223 buf[RTC_YR_REG_ADDR] = bin2bcd(tm->tm_year % 100);
224 buf[RTC_MON_REG_ADDR] = bin2bcd(tm->tm_mon);
225 buf[RTC_DAY_REG_ADDR] = bin2bcd(tm->tm_wday + 1);
226 buf[RTC_DATE_REG_ADDR] = bin2bcd(tm->tm_mday);
227 buf[RTC_HR_REG_ADDR] = bin2bcd(tm->tm_hour);
228 buf[RTC_MIN_REG_ADDR] = bin2bcd(tm->tm_min);
229 buf[RTC_SEC_REG_ADDR] = bin2bcd(tm->tm_sec);
231 if (type == mcp794xx) {
232 buf[RTC_DAY_REG_ADDR] |= MCP7941X_BIT_VBATEN;
233 buf[RTC_SEC_REG_ADDR] |= MCP7941X_BIT_ST;
236 ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
243 static int ds1307_rtc_get(struct udevice *dev, struct rtc_time *tm)
247 enum ds_type type = dev_get_driver_data(dev);
250 ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
254 if (type == ds_1307) {
255 if (buf[RTC_SEC_REG_ADDR] & RTC_SEC_BIT_CH) {
256 printf("### Warning: RTC oscillator has stopped\n");
257 /* clear the CH flag */
258 buf[RTC_SEC_REG_ADDR] &= ~RTC_SEC_BIT_CH;
259 dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
260 buf[RTC_SEC_REG_ADDR]);
265 if (type == m41t11) {
266 /* clock halted? turn it on, so clock can tick. */
267 if (buf[RTC_SEC_REG_ADDR] & RTC_SEC_BIT_CH) {
268 buf[RTC_SEC_REG_ADDR] &= ~RTC_SEC_BIT_CH;
269 dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
271 dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
272 buf[RTC_SEC_REG_ADDR]);
277 if (type == mcp794xx) {
278 /* make sure that the backup battery is enabled */
279 if (!(buf[RTC_DAY_REG_ADDR] & MCP7941X_BIT_VBATEN)) {
280 dm_i2c_reg_write(dev, RTC_DAY_REG_ADDR,
281 buf[RTC_DAY_REG_ADDR] |
282 MCP7941X_BIT_VBATEN);
285 /* clock halted? turn it on, so clock can tick. */
286 if (!(buf[RTC_SEC_REG_ADDR] & MCP7941X_BIT_ST)) {
287 dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
289 printf("Started RTC\n");
294 tm->tm_sec = bcd2bin(buf[RTC_SEC_REG_ADDR] & 0x7F);
295 tm->tm_min = bcd2bin(buf[RTC_MIN_REG_ADDR] & 0x7F);
296 tm->tm_hour = bcd2bin(buf[RTC_HR_REG_ADDR] & 0x3F);
297 tm->tm_mday = bcd2bin(buf[RTC_DATE_REG_ADDR] & 0x3F);
298 tm->tm_mon = bcd2bin(buf[RTC_MON_REG_ADDR] & 0x1F);
299 tm->tm_year = bcd2bin(buf[RTC_YR_REG_ADDR]) +
300 (bcd2bin(buf[RTC_YR_REG_ADDR]) >= 70 ?
302 tm->tm_wday = bcd2bin((buf[RTC_DAY_REG_ADDR] - 1) & 0x07);
306 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
307 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
308 tm->tm_hour, tm->tm_min, tm->tm_sec);
313 static int ds1307_rtc_reset(struct udevice *dev)
317 /* clear Clock Halt */
318 ret = dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR, 0x00);
321 ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR,
322 RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 |
330 static int ds1307_probe(struct udevice *dev)
332 i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
333 DM_I2C_CHIP_WR_ADDRESS);
338 static const struct rtc_ops ds1307_rtc_ops = {
339 .get = ds1307_rtc_get,
340 .set = ds1307_rtc_set,
341 .reset = ds1307_rtc_reset,
344 static const struct udevice_id ds1307_rtc_ids[] = {
345 { .compatible = "dallas,ds1307", .data = ds_1307 },
346 { .compatible = "dallas,ds1337", .data = ds_1337 },
347 { .compatible = "dallas,ds1340", .data = ds_1340 },
348 { .compatible = "microchip,mcp7941x", .data = mcp794xx },
349 { .compatible = "st,m41t11", .data = m41t11 },
353 U_BOOT_DRIVER(rtc_ds1307) = {
354 .name = "rtc-ds1307",
356 .probe = ds1307_probe,
357 .of_match = ds1307_rtc_ids,
358 .ops = &ds1307_rtc_ops,
360 #endif /* CONFIG_DM_RTC */