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
|
/*
* ST M48T86 / Dallas DS12887 RTC driver
* Copyright (c) 2006 Tower Technologies
*
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* 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.
*
* This drivers only supports the clock running in BCD and 24H mode.
* If it will be ever adapted to binary and 12H mode, care must be taken
* to not introduce bugs.
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/m48t86.h>
#include <linux/bcd.h>
#define M48T86_REG_SEC 0x00
#define M48T86_REG_SECALRM 0x01
#define M48T86_REG_MIN 0x02
#define M48T86_REG_MINALRM 0x03
#define M48T86_REG_HOUR 0x04
#define M48T86_REG_HOURALRM 0x05
#define M48T86_REG_DOW 0x06 /* 1 = sunday */
#define M48T86_REG_DOM 0x07
#define M48T86_REG_MONTH 0x08 /* 1 - 12 */
#define M48T86_REG_YEAR 0x09 /* 0 - 99 */
#define M48T86_REG_A 0x0A
#define M48T86_REG_B 0x0B
#define M48T86_REG_C 0x0C
#define M48T86_REG_D 0x0D
#define M48T86_REG_B_H24 (1 << 1)
#define M48T86_REG_B_DM (1 << 2)
#define M48T86_REG_B_SET (1 << 7)
#define M48T86_REG_D_VRT (1 << 7)
#define DRV_VERSION "0.1"
static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
unsigned char reg;
struct platform_device *pdev = to_platform_device(dev);
struct m48t86_ops *ops = pdev->dev.platform_data;
reg = ops->readbyte(M48T86_REG_B);
if (reg & M48T86_REG_B_DM) {
/* data (binary) mode */
tm->tm_sec = ops->readbyte(M48T86_REG_SEC);
tm->tm_min = ops->readbyte(M48T86_REG_MIN);
tm->tm_hour = ops->readbyte(M48T86_REG_HOUR) & 0x3F;
tm->tm_mday = ops->readbyte(M48T86_REG_DOM);
/* tm_mon is 0-11 */
tm->tm_mon = ops->readbyte(M48T86_REG_MONTH) - 1;
tm->tm_year = ops->readbyte(M48T86_REG_YEAR) + 100;
tm->tm_wday = ops->readbyte(M48T86_REG_DOW);
} else {
/* bcd mode */
tm->tm_sec = bcd2bin(ops->readbyte(M48T86_REG_SEC));
tm->tm_min = bcd2bin(ops->readbyte(M48T86_REG_MIN));
tm->tm_hour = bcd2bin(ops->readbyte(M48T86_REG_HOUR) & 0x3F);
tm->tm_mday = bcd2bin(ops->readbyte(M48T86_REG_DOM));
/* tm_mon is 0-11 */
tm->tm_mon = bcd2bin(ops->readbyte(M48T86_REG_MONTH)) - 1;
tm->tm_year = bcd2bin(ops->readbyte(M48T86_REG_YEAR)) + 100;
tm->tm_wday = bcd2bin(ops->readbyte(M48T86_REG_DOW));
}
/* correct the hour if the clock is in 12h mode */
if (!(reg & M48T86_REG_B_H24))
if (ops->readbyte(M48T86_REG_HOUR) & 0x80)
tm->tm_hour += 12;
return rtc_valid_tm(tm);
}
static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
unsigned char reg;
struct platform_device *pdev = to_platform_device(dev);
struct m48t86_ops *ops = pdev->dev.platform_data;
reg = ops->readbyte(M48T86_REG_B);
/* update flag and 24h mode */
reg |= M48T86_REG_B_SET | M48T86_REG_B_H24;
ops->writebyte(reg, M48T86_REG_B);
if (reg & M48T86_REG_B_DM) {
/* data (binary) mode */
ops->writebyte(tm->tm_sec, M48T86_REG_SEC);
ops->writebyte(tm->tm_min, M48T86_REG_MIN);
ops->writebyte(tm->tm_hour, M48T86_REG_HOUR);
ops->writebyte(tm->tm_mday, M48T86_REG_DOM);
ops->writebyte(tm->tm_mon + 1, M48T86_REG_MONTH);
ops->writebyte(tm->tm_year % 100, M48T86_REG_YEAR);
ops->writebyte(tm->tm_wday, M48T86_REG_DOW);
} else {
/* bcd mode */
ops->writebyte(bin2bcd(tm->tm_sec), M48T86_REG_SEC);
ops->writebyte(bin2bcd(tm->tm_min), M48T86_REG_MIN);
ops->writebyte(bin2bcd(tm->tm_hour), M48T86_REG_HOUR);
ops->writebyte(bin2bcd(tm->tm_mday), M48T86_REG_DOM);
ops->writebyte(bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH);
ops->writebyte(bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR);
ops->writebyte(bin2bcd(tm->tm_wday), M48T86_REG_DOW);
}
/* update ended */
reg &= ~M48T86_REG_B_SET;
ops->writebyte(reg, M48T86_REG_B);
return 0;
}
static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
{
unsigned char reg;
struct platform_device *pdev = to_platform_device(dev);
struct m48t86_ops *ops = pdev->dev.platform_data;
reg = ops->readbyte(M48T86_REG_B);
seq_printf(seq, "mode\t\t: %s\n",
(reg & M48T86_REG_B_DM) ? "binary" : "bcd");
reg = ops->readbyte(M48T86_REG_D);
seq_printf(seq, "battery\t\t: %s\n",
(reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
return 0;
}
static const struct rtc_class_ops m48t86_rtc_ops = {
.read_time = m48t86_rtc_read_time,
.set_time = m48t86_rtc_set_time,
.proc = m48t86_rtc_proc,
};
static int m48t86_rtc_probe(struct platform_device *dev)
{
unsigned char reg;
struct m48t86_ops *ops = dev->dev.platform_data;
struct rtc_device *rtc;
rtc = devm_rtc_device_register(&dev->dev, "m48t86",
&m48t86_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
platform_set_drvdata(dev, rtc);
/* read battery status */
reg = ops->readbyte(M48T86_REG_D);
dev_info(&dev->dev, "battery %s\n",
(reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
return 0;
}
static struct platform_driver m48t86_rtc_platform_driver = {
.driver = {
.name = "rtc-m48t86",
.owner = THIS_MODULE,
},
.probe = m48t86_rtc_probe,
};
module_platform_driver(m48t86_rtc_platform_driver);
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("M48T86 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_ALIAS("platform:rtc-m48t86");
|
