summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/m41t62.c
blob: 94a6b523aab3630582575dddc7c9151a66a03e80 (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
// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2018
 * Lukasz Majewski, DENX Software Engineering, lukma@denx.de.
 *
 * (C) Copyright 2008
 * Stefan Roese, DENX Software Engineering, sr@denx.de.
 *
 * based on a the Linux rtc-m41t80.c driver which is:
 *   Alexander Bigga <ab@mycable.de>, 2006 (c) mycable GmbH
 */

/*
 * Date & Time support for STMicroelectronics M41T62
 */

/* #define	DEBUG	*/

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

#define M41T62_REG_SSEC	0
#define M41T62_REG_SEC	1
#define M41T62_REG_MIN	2
#define M41T62_REG_HOUR	3
#define M41T62_REG_WDAY	4
#define M41T62_REG_DAY	5
#define M41T62_REG_MON	6
#define M41T62_REG_YEAR	7
#define M41T62_REG_ALARM_MON	0xa
#define M41T62_REG_ALARM_DAY	0xb
#define M41T62_REG_ALARM_HOUR	0xc
#define M41T62_REG_ALARM_MIN	0xd
#define M41T62_REG_ALARM_SEC	0xe
#define M41T62_REG_FLAGS	0xf

#define M41T62_DATETIME_REG_SIZE	(M41T62_REG_YEAR + 1)
#define M41T62_ALARM_REG_SIZE	\
	(M41T62_REG_ALARM_SEC + 1 - M41T62_REG_ALARM_MON)

#define M41T62_SEC_ST		(1 << 7)	/* ST: Stop Bit */
#define M41T62_ALMON_AFE	(1 << 7)	/* AFE: AF Enable Bit */
#define M41T62_ALMON_SQWE	(1 << 6)	/* SQWE: SQW Enable Bit */
#define M41T62_ALHOUR_HT	(1 << 6)	/* HT: Halt Update Bit */
#define M41T62_FLAGS_AF		(1 << 6)	/* AF: Alarm Flag Bit */
#define M41T62_FLAGS_BATT_LOW	(1 << 4)	/* BL: Battery Low Bit */

#define M41T62_FEATURE_HT	(1 << 0)
#define M41T62_FEATURE_BL	(1 << 1)

#define M41T80_ALHOUR_HT	(1 << 6)	/* HT: Halt Update Bit */

static void m41t62_update_rtc_time(struct rtc_time *tm, u8 *buf)
{
	debug("%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
	      "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
	      __FUNCTION__,
	      buf[0], buf[1], buf[2], buf[3],
	      buf[4], buf[5], buf[6], buf[7]);

	tm->tm_sec = bcd2bin(buf[M41T62_REG_SEC] & 0x7f);
	tm->tm_min = bcd2bin(buf[M41T62_REG_MIN] & 0x7f);
	tm->tm_hour = bcd2bin(buf[M41T62_REG_HOUR] & 0x3f);
	tm->tm_mday = bcd2bin(buf[M41T62_REG_DAY] & 0x3f);
	tm->tm_wday = buf[M41T62_REG_WDAY] & 0x07;
	tm->tm_mon = bcd2bin(buf[M41T62_REG_MON] & 0x1f);

	/* assume 20YY not 19YY, and ignore the Century Bit */
	/* U-Boot needs to add 1900 here */
	tm->tm_year = bcd2bin(buf[M41T62_REG_YEAR]) + 100 + 1900;

	debug("%s: tm is secs=%d, mins=%d, hours=%d, "
	      "mday=%d, mon=%d, year=%d, wday=%d\n",
	      __FUNCTION__,
	      tm->tm_sec, tm->tm_min, tm->tm_hour,
	      tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
}

static void m41t62_set_rtc_buf(const struct rtc_time *tm, u8 *buf)
{
	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);

	/* Merge time-data and register flags into buf[0..7] */
	buf[M41T62_REG_SSEC] = 0;
	buf[M41T62_REG_SEC] =
		bin2bcd(tm->tm_sec) | (buf[M41T62_REG_SEC] & ~0x7f);
	buf[M41T62_REG_MIN] =
		bin2bcd(tm->tm_min) | (buf[M41T62_REG_MIN] & ~0x7f);
	buf[M41T62_REG_HOUR] =
		bin2bcd(tm->tm_hour) | (buf[M41T62_REG_HOUR] & ~0x3f) ;
	buf[M41T62_REG_WDAY] =
		(tm->tm_wday & 0x07) | (buf[M41T62_REG_WDAY] & ~0x07);
	buf[M41T62_REG_DAY] =
		bin2bcd(tm->tm_mday) | (buf[M41T62_REG_DAY] & ~0x3f);
	buf[M41T62_REG_MON] =
		bin2bcd(tm->tm_mon) | (buf[M41T62_REG_MON] & ~0x1f);
	/* assume 20YY not 19YY */
	buf[M41T62_REG_YEAR] = bin2bcd(tm->tm_year % 100);
}

#ifdef CONFIG_DM_RTC
static int m41t62_rtc_get(struct udevice *dev, struct rtc_time *tm)
{
	u8 buf[M41T62_DATETIME_REG_SIZE];
	int ret;

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

	m41t62_update_rtc_time(tm, buf);

	return 0;
}

static int m41t62_rtc_set(struct udevice *dev, const struct rtc_time *tm)
{
	u8 buf[M41T62_DATETIME_REG_SIZE];
	int ret;

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

	m41t62_set_rtc_buf(tm, buf);

	ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
	if (ret) {
		printf("I2C write failed in %s()\n", __func__);
		return ret;
	}

	return 0;
}

static int m41t62_rtc_reset(struct udevice *dev)
{
	u8 val;

	/*
	 * M41T82: Make sure HT (Halt Update) bit is cleared.
	 * This bit is 0 in M41T62 so its save to clear it always.
	 */

	int ret = dm_i2c_read(dev, M41T62_REG_ALARM_HOUR, &val, sizeof(val));

	val &= ~M41T80_ALHOUR_HT;
	ret |= dm_i2c_write(dev, M41T62_REG_ALARM_HOUR, &val, sizeof(val));

	return ret;
}

/*
 * Make sure HT bit is cleared. This bit is set on entering battery backup
 * mode, so do this before the first read access.
 */
static int m41t62_rtc_probe(struct udevice *dev)
{
	return m41t62_rtc_reset(dev);
}

static const struct rtc_ops m41t62_rtc_ops = {
	.get = m41t62_rtc_get,
	.set = m41t62_rtc_set,
	.reset = m41t62_rtc_reset,
};

static const struct udevice_id m41t62_rtc_ids[] = {
	{ .compatible = "st,m41t62" },
	{ .compatible = "st,m41t82" },
	{ .compatible = "st,m41st87" },
	{ .compatible = "microcrystal,rv4162" },
	{ }
};

U_BOOT_DRIVER(rtc_m41t62) = {
	.name	= "rtc-m41t62",
	.id	= UCLASS_RTC,
	.of_match = m41t62_rtc_ids,
	.ops	= &m41t62_rtc_ops,
	.probe  = &m41t62_rtc_probe,
};

#else /* NON DM RTC code - will be removed */
int rtc_get(struct rtc_time *tm)
{
	u8 buf[M41T62_DATETIME_REG_SIZE];

	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
	m41t62_update_rtc_time(tm, buf);

	return 0;
}

int rtc_set(struct rtc_time *tm)
{
	u8 buf[M41T62_DATETIME_REG_SIZE];

	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
	m41t62_set_rtc_buf(tm, buf);

	if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf,
		      M41T62_DATETIME_REG_SIZE)) {
		printf("I2C write failed in %s()\n", __func__);
		return -1;
	}

	return 0;
}

void rtc_reset(void)
{
	u8 val;

	/*
	 * M41T82: Make sure HT (Halt Update) bit is cleared.
	 * This bit is 0 in M41T62 so its save to clear it always.
	 */
	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T62_REG_ALARM_HOUR, 1, &val, 1);
	val &= ~M41T80_ALHOUR_HT;
	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T62_REG_ALARM_HOUR, 1, &val, 1);
}
#endif /* CONFIG_DM_RTC */