aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/ds1307.c
blob: 48220b45db1d689c7fbde6fa26e06229f6db8fc4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2001, 2002, 2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 * Keith Outwater, keith_outwater@mvis.com`
 * Steven Scholz, steven.scholz@imc-berlin.de
 */

/*
 * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
 * DS1307 and DS1338/9 Real Time Clock (RTC).
 *
 * based on ds1337.c
 */

#include <common.h>
#include <command.h>
#include <dm.h>
#include <rtc.h>
#include <i2c.h>

enum ds_type {
	ds_1307,
	ds_1337,
	ds_1340,
	mcp794xx,
};

/*
 * RTC register addresses
 */
#define RTC_SEC_REG_ADDR	0x00
#define RTC_MIN_REG_ADDR	0x01
#define RTC_HR_REG_ADDR		0x02
#define RTC_DAY_REG_ADDR	0x03
#define RTC_DATE_REG_ADDR	0x04
#define RTC_MON_REG_ADDR	0x05
#define RTC_YR_REG_ADDR		0x06
#define RTC_CTL_REG_ADDR	0x07

#define RTC_SEC_BIT_CH		0x80	/* Clock Halt (in Register 0)   */

#define RTC_CTL_BIT_RS0		0x01	/* Rate select 0                */
#define RTC_CTL_BIT_RS1		0x02	/* Rate select 1                */
#define RTC_CTL_BIT_SQWE	0x10	/* Square Wave Enable           */
#define RTC_CTL_BIT_OUT		0x80	/* Output Control               */

/* MCP7941X-specific bits */
#define MCP7941X_BIT_ST		0x80
#define MCP7941X_BIT_VBATEN	0x08

#ifndef CONFIG_DM_RTC

/*---------------------------------------------------------------------*/
#undef DEBUG_RTC

#ifdef DEBUG_RTC
#define DEBUGR(fmt, args...) printf(fmt, ##args)
#else
#define DEBUGR(fmt, args...)
#endif
/*---------------------------------------------------------------------*/

#ifndef CONFIG_SYS_I2C_RTC_ADDR
# define CONFIG_SYS_I2C_RTC_ADDR	0x68
#endif

#if defined(CONFIG_RTC_DS1307) && (CONFIG_SYS_I2C_SPEED > 100000)
# error The DS1307 is specified only up to 100kHz!
#endif

static uchar rtc_read (uchar reg);
static void rtc_write (uchar reg, uchar val);

/*
 * Get the current time from the RTC
 */
int rtc_get (struct rtc_time *tmp)
{
	int rel = 0;
	uchar sec, min, hour, mday, wday, mon, year;

#ifdef CONFIG_RTC_MCP79411
read_rtc:
#endif
	sec = rtc_read (RTC_SEC_REG_ADDR);
	min = rtc_read (RTC_MIN_REG_ADDR);
	hour = rtc_read (RTC_HR_REG_ADDR);
	wday = rtc_read (RTC_DAY_REG_ADDR);
	mday = rtc_read (RTC_DATE_REG_ADDR);
	mon = rtc_read (RTC_MON_REG_ADDR);
	year = rtc_read (RTC_YR_REG_ADDR);

	DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
		"hr: %02x min: %02x sec: %02x\n",
		year, mon, mday, wday, hour, min, sec);

#ifdef CONFIG_RTC_DS1307
	if (sec & RTC_SEC_BIT_CH) {
		printf ("### Warning: RTC oscillator has stopped\n");
		/* clear the CH flag */
		rtc_write (RTC_SEC_REG_ADDR,
			   rtc_read (RTC_SEC_REG_ADDR) & ~RTC_SEC_BIT_CH);
		rel = -1;
	}
#endif

#ifdef CONFIG_RTC_MCP79411
	/* make sure that the backup battery is enabled */
	if (!(wday & MCP7941X_BIT_VBATEN)) {
		rtc_write(RTC_DAY_REG_ADDR,
			  wday | MCP7941X_BIT_VBATEN);
	}

	/* clock halted?  turn it on, so clock can tick. */
	if (!(sec & MCP7941X_BIT_ST)) {
		rtc_write(RTC_SEC_REG_ADDR, MCP7941X_BIT_ST);
		printf("Started RTC\n");
		goto read_rtc;
	}
#endif


	tmp->tm_sec  = bcd2bin (sec & 0x7F);
	tmp->tm_min  = bcd2bin (min & 0x7F);
	tmp->tm_hour = bcd2bin (hour & 0x3F);
	tmp->tm_mday = bcd2bin (mday & 0x3F);
	tmp->tm_mon  = bcd2bin (mon & 0x1F);
	tmp->tm_year = bcd2bin (year) + ( bcd2bin (year) >= 70 ? 1900 : 2000);
	tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
	tmp->tm_yday = 0;
	tmp->tm_isdst= 0;

	DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);

	return rel;
}


/*
 * Set the RTC
 */
int rtc_set (struct rtc_time *tmp)
{
	DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);

	if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
		printf("WARNING: year should be between 1970 and 2069!\n");

	rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
	rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
#ifdef CONFIG_RTC_MCP79411
	rtc_write (RTC_DAY_REG_ADDR,
		   bin2bcd (tmp->tm_wday + 1) | MCP7941X_BIT_VBATEN);
#else
	rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
#endif
	rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
	rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
	rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
#ifdef CONFIG_RTC_MCP79411
	rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec) | MCP7941X_BIT_ST);
#else
	rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
#endif

	return 0;
}


/*
 * Reset the RTC. We setting the date back to 1970-01-01.
 * We also enable the oscillator output on the SQW/OUT pin and program
 * it for 32,768 Hz output. Note that according to the datasheet, turning
 * on the square wave output increases the current drain on the backup
 * battery to something between 480nA and 800nA.
 */
void rtc_reset (void)
{
	rtc_write (RTC_SEC_REG_ADDR, 0x00);	/* clearing Clock Halt	*/
	rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS0);
}


/*
 * Helper functions
 */

static
uchar rtc_read (uchar reg)
{
	return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
}


static void rtc_write (uchar reg, uchar val)
{
	i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
}

#endif /* !CONFIG_DM_RTC */

#ifdef CONFIG_DM_RTC
static int ds1307_rtc_set(struct udevice *dev, const struct rtc_time *tm)
{
	int ret;
	uchar buf[7];
	enum ds_type type = dev_get_driver_data(dev);

	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
	      tm->tm_hour, tm->tm_min, tm->tm_sec);

	if (tm->tm_year < 1970 || tm->tm_year > 2069)
		printf("WARNING: year should be between 1970 and 2069!\n");

	buf[RTC_YR_REG_ADDR] = bin2bcd(tm->tm_year % 100);
	buf[RTC_MON_REG_ADDR] = bin2bcd(tm->tm_mon);
	buf[RTC_DAY_REG_ADDR] = bin2bcd(tm->tm_wday + 1);
	buf[RTC_DATE_REG_ADDR] = bin2bcd(tm->tm_mday);
	buf[RTC_HR_REG_ADDR] = bin2bcd(tm->tm_hour);
	buf[RTC_MIN_REG_ADDR] = bin2bcd(tm->tm_min);
	buf[RTC_SEC_REG_ADDR] = bin2bcd(tm->tm_sec);

	if (type == mcp794xx) {
		buf[RTC_DAY_REG_ADDR] |= MCP7941X_BIT_VBATEN;
		buf[RTC_SEC_REG_ADDR] |= MCP7941X_BIT_ST;
	}

	ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
	if (ret < 0)
		return ret;

	return 0;
}

static int ds1307_rtc_get(struct udevice *dev, struct rtc_time *tm)
{
	int ret;
	uchar buf[7];
	enum ds_type type = dev_get_driver_data(dev);

read_rtc:
	ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
	if (ret < 0)
		return ret;

	if (type == ds_1307) {
		if (buf[RTC_SEC_REG_ADDR] & RTC_SEC_BIT_CH) {
			printf("### Warning: RTC oscillator has stopped\n");
			/* clear the CH flag */
			buf[RTC_SEC_REG_ADDR] &= ~RTC_SEC_BIT_CH;
			dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
					 buf[RTC_SEC_REG_ADDR]);
			return -1;
		}
	}

	if (type == mcp794xx) {
		/* make sure that the backup battery is enabled */
		if (!(buf[RTC_DAY_REG_ADDR] & MCP7941X_BIT_VBATEN)) {
			dm_i2c_reg_write(dev, RTC_DAY_REG_ADDR,
					 buf[RTC_DAY_REG_ADDR] |
					 MCP7941X_BIT_VBATEN);
		}

		/* clock halted?  turn it on, so clock can tick. */
		if (!(buf[RTC_SEC_REG_ADDR] & MCP7941X_BIT_ST)) {
			dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
					 MCP7941X_BIT_ST);
			printf("Started RTC\n");
			goto read_rtc;
		}
	}

	tm->tm_sec  = bcd2bin(buf[RTC_SEC_REG_ADDR] & 0x7F);
	tm->tm_min  = bcd2bin(buf[RTC_MIN_REG_ADDR] & 0x7F);
	tm->tm_hour = bcd2bin(buf[RTC_HR_REG_ADDR] & 0x3F);
	tm->tm_mday = bcd2bin(buf[RTC_DATE_REG_ADDR] & 0x3F);
	tm->tm_mon  = bcd2bin(buf[RTC_MON_REG_ADDR] & 0x1F);
	tm->tm_year = bcd2bin(buf[RTC_YR_REG_ADDR]) +
			      (bcd2bin(buf[RTC_YR_REG_ADDR]) >= 70 ?
			       1900 : 2000);
	tm->tm_wday = bcd2bin((buf[RTC_DAY_REG_ADDR] - 1) & 0x07);
	tm->tm_yday = 0;
	tm->tm_isdst = 0;

	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
	      tm->tm_hour, tm->tm_min, tm->tm_sec);

	return 0;
}

static int ds1307_rtc_reset(struct udevice *dev)
{
	int ret;

	/* clear Clock Halt */
	ret = dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR, 0x00);
	if (ret < 0)
		return ret;
	ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR,
			       RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 |
			       RTC_CTL_BIT_RS0);
	if (ret < 0)
		return ret;

	return 0;
}

static int ds1307_probe(struct udevice *dev)
{
	i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
			   DM_I2C_CHIP_WR_ADDRESS);

	return 0;
}

static const struct rtc_ops ds1307_rtc_ops = {
	.get = ds1307_rtc_get,
	.set = ds1307_rtc_set,
	.reset = ds1307_rtc_reset,
};

static const struct udevice_id ds1307_rtc_ids[] = {
	{ .compatible = "dallas,ds1307", .data = ds_1307 },
	{ .compatible = "dallas,ds1337", .data = ds_1337 },
	{ .compatible = "dallas,ds1340", .data = ds_1340 },
	{ .compatible = "microchip,mcp7941x", .data = mcp794xx },
	{ }
};

U_BOOT_DRIVER(rtc_ds1307) = {
	.name	= "rtc-ds1307",
	.id	= UCLASS_RTC,
	.probe	= ds1307_probe,
	.of_match = ds1307_rtc_ids,
	.ops	= &ds1307_rtc_ops,
};
#endif /* CONFIG_DM_RTC */