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
|
// SPDX-License-Identifier: GPL-2.0
/*
* An rtc/i2c driver for the Dallas DS1672
* Copyright 2005-06 Tower Technologies
*
* Author: Alessandro Zummo <a.zummo@towertech.it>
*/
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/module.h>
/* Registers */
#define DS1672_REG_CNT_BASE 0
#define DS1672_REG_CONTROL 4
#define DS1672_REG_TRICKLE 5
#define DS1672_REG_CONTROL_EOSC 0x80
/*
* In the routines that deal directly with the ds1672 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
* Time is set to UTC.
*/
static int ds1672_read_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned long time;
unsigned char addr = DS1672_REG_CONTROL;
unsigned char buf[4];
struct i2c_msg msgs[] = {
{/* setup read ptr */
.addr = client->addr,
.len = 1,
.buf = &addr
},
{/* read date */
.addr = client->addr,
.flags = I2C_M_RD,
.len = 1,
.buf = buf
},
};
/* read control register */
if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
dev_warn(&client->dev, "Unable to read the control register\n");
return -EIO;
}
if (buf[0] & DS1672_REG_CONTROL_EOSC) {
dev_warn(&client->dev, "Oscillator not enabled. Set time to enable.\n");
return -EINVAL;
}
addr = DS1672_REG_CNT_BASE;
msgs[1].len = 4;
/* read date registers */
if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
dev_dbg(&client->dev,
"%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
__func__, buf[0], buf[1], buf[2], buf[3]);
time = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
(buf[1] << 8) | buf[0];
rtc_time64_to_tm(time, tm);
dev_dbg(&client->dev, "%s: tm is %ptR\n", __func__, tm);
return 0;
}
static int ds1672_set_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
int xfer;
unsigned char buf[6];
unsigned long secs = rtc_tm_to_time64(tm);
buf[0] = DS1672_REG_CNT_BASE;
buf[1] = secs & 0x000000FF;
buf[2] = (secs & 0x0000FF00) >> 8;
buf[3] = (secs & 0x00FF0000) >> 16;
buf[4] = (secs & 0xFF000000) >> 24;
buf[5] = 0; /* set control reg to enable counting */
xfer = i2c_master_send(client, buf, 6);
if (xfer != 6) {
dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
return -EIO;
}
return 0;
}
static const struct rtc_class_ops ds1672_rtc_ops = {
.read_time = ds1672_read_time,
.set_time = ds1672_set_time,
};
static int ds1672_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int err = 0;
struct rtc_device *rtc;
dev_dbg(&client->dev, "%s\n", __func__);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
rtc = devm_rtc_allocate_device(&client->dev);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
rtc->ops = &ds1672_rtc_ops;
rtc->range_max = U32_MAX;
err = rtc_register_device(rtc);
if (err)
return err;
i2c_set_clientdata(client, rtc);
return 0;
}
static const struct i2c_device_id ds1672_id[] = {
{ "ds1672", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds1672_id);
static const struct of_device_id ds1672_of_match[] = {
{ .compatible = "dallas,ds1672" },
{ }
};
MODULE_DEVICE_TABLE(of, ds1672_of_match);
static struct i2c_driver ds1672_driver = {
.driver = {
.name = "rtc-ds1672",
.of_match_table = of_match_ptr(ds1672_of_match),
},
.probe = &ds1672_probe,
.id_table = ds1672_id,
};
module_i2c_driver(ds1672_driver);
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
MODULE_LICENSE("GPL");
|
