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
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Dallas DS1216 RTC driver
*
* Copyright (c) 2007 Thomas Bogendoerfer
*
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/bcd.h>
#include <linux/slab.h>
struct ds1216_regs {
u8 tsec;
u8 sec;
u8 min;
u8 hour;
u8 wday;
u8 mday;
u8 month;
u8 year;
};
#define DS1216_HOUR_1224 (1 << 7)
#define DS1216_HOUR_AMPM (1 << 5)
struct ds1216_priv {
struct rtc_device *rtc;
void __iomem *ioaddr;
};
static const u8 magic[] = {
0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
};
/*
* Read the 64 bit we'd like to have - It a series
* of 64 bits showing up in the LSB of the base register.
*
*/
static void ds1216_read(u8 __iomem *ioaddr, u8 *buf)
{
unsigned char c;
int i, j;
for (i = 0; i < 8; i++) {
c = 0;
for (j = 0; j < 8; j++)
c |= (readb(ioaddr) & 0x1) << j;
buf[i] = c;
}
}
static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf)
{
unsigned char c;
int i, j;
for (i = 0; i < 8; i++) {
c = buf[i];
for (j = 0; j < 8; j++) {
writeb(c, ioaddr);
c = c >> 1;
}
}
}
static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr)
{
/* Reset magic pointer */
readb(ioaddr);
/* Write 64 bit magic to DS1216 */
ds1216_write(ioaddr, magic);
}
static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct ds1216_priv *priv = dev_get_drvdata(dev);
struct ds1216_regs regs;
ds1216_switch_ds_to_clock(priv->ioaddr);
ds1216_read(priv->ioaddr, (u8 *)®s);
tm->tm_sec = bcd2bin(regs.sec);
tm->tm_min = bcd2bin(regs.min);
if (regs.hour & DS1216_HOUR_1224) {
/* AM/PM mode */
tm->tm_hour = bcd2bin(regs.hour & 0x1f);
if (regs.hour & DS1216_HOUR_AMPM)
tm->tm_hour += 12;
} else
tm->tm_hour = bcd2bin(regs.hour & 0x3f);
tm->tm_wday = (regs.wday & 7) - 1;
tm->tm_mday = bcd2bin(regs.mday & 0x3f);
tm->tm_mon = bcd2bin(regs.month & 0x1f);
tm->tm_year = bcd2bin(regs.year);
if (tm->tm_year < 70)
tm->tm_year += 100;
return 0;
}
static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct ds1216_priv *priv = dev_get_drvdata(dev);
struct ds1216_regs regs;
ds1216_switch_ds_to_clock(priv->ioaddr);
ds1216_read(priv->ioaddr, (u8 *)®s);
regs.tsec = 0; /* clear 0.1 and 0.01 seconds */
regs.sec = bin2bcd(tm->tm_sec);
regs.min = bin2bcd(tm->tm_min);
regs.hour &= DS1216_HOUR_1224;
if (regs.hour && tm->tm_hour > 12) {
regs.hour |= DS1216_HOUR_AMPM;
tm->tm_hour -= 12;
}
regs.hour |= bin2bcd(tm->tm_hour);
regs.wday &= ~7;
regs.wday |= tm->tm_wday;
regs.mday = bin2bcd(tm->tm_mday);
regs.month = bin2bcd(tm->tm_mon);
regs.year = bin2bcd(tm->tm_year % 100);
ds1216_switch_ds_to_clock(priv->ioaddr);
ds1216_write(priv->ioaddr, (u8 *)®s);
return 0;
}
static const struct rtc_class_ops ds1216_rtc_ops = {
.read_time = ds1216_rtc_read_time,
.set_time = ds1216_rtc_set_time,
};
static int __init ds1216_rtc_probe(struct platform_device *pdev)
{
struct ds1216_priv *priv;
u8 dummy[8];
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
platform_set_drvdata(pdev, priv);
priv->ioaddr = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->ioaddr))
return PTR_ERR(priv->ioaddr);
priv->rtc = devm_rtc_device_register(&pdev->dev, "ds1216",
&ds1216_rtc_ops, THIS_MODULE);
if (IS_ERR(priv->rtc))
return PTR_ERR(priv->rtc);
/* dummy read to get clock into a known state */
ds1216_read(priv->ioaddr, dummy);
return 0;
}
static struct platform_driver ds1216_rtc_platform_driver = {
.driver = {
.name = "rtc-ds1216",
},
};
module_platform_driver_probe(ds1216_rtc_platform_driver, ds1216_rtc_probe);
MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
MODULE_DESCRIPTION("DS1216 RTC driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rtc-ds1216");
|
