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
|
/* rtc-ds3234.c
*
* Driver for Dallas Semiconductor (DS3234) SPI RTC with Integrated Crystal
* and SRAM.
*
* Copyright (C) 2008 MIMOMax Wireless Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/spi/spi.h>
#include <linux/bcd.h>
#define DS3234_REG_SECONDS 0x00
#define DS3234_REG_MINUTES 0x01
#define DS3234_REG_HOURS 0x02
#define DS3234_REG_DAY 0x03
#define DS3234_REG_DATE 0x04
#define DS3234_REG_MONTH 0x05
#define DS3234_REG_YEAR 0x06
#define DS3234_REG_CENTURY (1 << 7) /* Bit 7 of the Month register */
#define DS3234_REG_CONTROL 0x0E
#define DS3234_REG_CONT_STAT 0x0F
static int ds3234_set_reg(struct device *dev, unsigned char address,
unsigned char data)
{
struct spi_device *spi = to_spi_device(dev);
unsigned char buf[2];
/* MSB must be '1' to indicate write */
buf[0] = address | 0x80;
buf[1] = data;
return spi_write_then_read(spi, buf, 2, NULL, 0);
}
static int ds3234_get_reg(struct device *dev, unsigned char address,
unsigned char *data)
{
struct spi_device *spi = to_spi_device(dev);
*data = address & 0x7f;
return spi_write_then_read(spi, data, 1, data, 1);
}
static int ds3234_read_time(struct device *dev, struct rtc_time *dt)
{
int err;
unsigned char buf[8];
struct spi_device *spi = to_spi_device(dev);
buf[0] = 0x00; /* Start address */
err = spi_write_then_read(spi, buf, 1, buf, 8);
if (err != 0)
return err;
/* Seconds, Minutes, Hours, Day, Date, Month, Year */
dt->tm_sec = bcd2bin(buf[0]);
dt->tm_min = bcd2bin(buf[1]);
dt->tm_hour = bcd2bin(buf[2] & 0x3f);
dt->tm_wday = bcd2bin(buf[3]) - 1; /* 0 = Sun */
dt->tm_mday = bcd2bin(buf[4]);
dt->tm_mon = bcd2bin(buf[5] & 0x1f) - 1; /* 0 = Jan */
dt->tm_year = bcd2bin(buf[6] & 0xff) + 100; /* Assume 20YY */
return rtc_valid_tm(dt);
}
static int ds3234_set_time(struct device *dev, struct rtc_time *dt)
{
ds3234_set_reg(dev, DS3234_REG_SECONDS, bin2bcd(dt->tm_sec));
ds3234_set_reg(dev, DS3234_REG_MINUTES, bin2bcd(dt->tm_min));
ds3234_set_reg(dev, DS3234_REG_HOURS, bin2bcd(dt->tm_hour) & 0x3f);
/* 0 = Sun */
ds3234_set_reg(dev, DS3234_REG_DAY, bin2bcd(dt->tm_wday + 1));
ds3234_set_reg(dev, DS3234_REG_DATE, bin2bcd(dt->tm_mday));
/* 0 = Jan */
ds3234_set_reg(dev, DS3234_REG_MONTH, bin2bcd(dt->tm_mon + 1));
/* Assume 20YY although we just want to make sure not to go negative. */
if (dt->tm_year > 100)
dt->tm_year -= 100;
ds3234_set_reg(dev, DS3234_REG_YEAR, bin2bcd(dt->tm_year));
return 0;
}
static const struct rtc_class_ops ds3234_rtc_ops = {
.read_time = ds3234_read_time,
.set_time = ds3234_set_time,
};
static int ds3234_probe(struct spi_device *spi)
{
struct rtc_device *rtc;
unsigned char tmp;
int res;
spi->mode = SPI_MODE_3;
spi->bits_per_word = 8;
spi_setup(spi);
res = ds3234_get_reg(&spi->dev, DS3234_REG_SECONDS, &tmp);
if (res != 0)
return res;
/* Control settings
*
* CONTROL_REG
* BIT 7 6 5 4 3 2 1 0
* EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE
*
* 0 0 0 1 1 1 0 0
*
* CONTROL_STAT_REG
* BIT 7 6 5 4 3 2 1 0
* OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F
*
* 1 0 0 0 1 0 0 0
*/
ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
ds3234_set_reg(&spi->dev, DS3234_REG_CONTROL, tmp & 0x1c);
ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
ds3234_set_reg(&spi->dev, DS3234_REG_CONT_STAT, tmp & 0x88);
/* Print our settings */
ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
rtc = devm_rtc_device_register(&spi->dev, "ds3234",
&ds3234_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
spi_set_drvdata(spi, rtc);
return 0;
}
static struct spi_driver ds3234_driver = {
.driver = {
.name = "ds3234",
},
.probe = ds3234_probe,
};
module_spi_driver(ds3234_driver);
MODULE_DESCRIPTION("DS3234 SPI RTC driver");
MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:ds3234");
|
