forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
rtc-m48t35.c
194 lines (166 loc) · 4.65 KB
/
rtc-m48t35.c
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
/*
* Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
*
* Copyright (C) 2000 Silicon Graphics, Inc.
* Written by Ulf Carlsson ([email protected])
*
* Copyright (C) 2008 Thomas Bogendoerfer
*
* Based on code written by Paul Gortmaker.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/bcd.h>
#include <linux/io.h>
#include <linux/err.h>
#define DRV_VERSION "1.0"
struct m48t35_rtc {
u8 pad[0x7ff8]; /* starts at 0x7ff8 */
u8 control;
u8 sec;
u8 min;
u8 hour;
u8 day;
u8 date;
u8 month;
u8 year;
};
#define M48T35_RTC_SET 0x80
#define M48T35_RTC_READ 0x40
struct m48t35_priv {
struct rtc_device *rtc;
struct m48t35_rtc __iomem *reg;
size_t size;
unsigned long baseaddr;
spinlock_t lock;
};
static int m48t35_read_time(struct device *dev, struct rtc_time *tm)
{
struct m48t35_priv *priv = dev_get_drvdata(dev);
u8 control;
/*
* Only the values that we read from the RTC are set. We leave
* tm_wday, tm_yday and tm_isdst untouched. Even though the
* RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
* by the RTC when initially set to a non-zero value.
*/
spin_lock_irq(&priv->lock);
control = readb(&priv->reg->control);
writeb(control | M48T35_RTC_READ, &priv->reg->control);
tm->tm_sec = readb(&priv->reg->sec);
tm->tm_min = readb(&priv->reg->min);
tm->tm_hour = readb(&priv->reg->hour);
tm->tm_mday = readb(&priv->reg->date);
tm->tm_mon = readb(&priv->reg->month);
tm->tm_year = readb(&priv->reg->year);
writeb(control, &priv->reg->control);
spin_unlock_irq(&priv->lock);
tm->tm_sec = bcd2bin(tm->tm_sec);
tm->tm_min = bcd2bin(tm->tm_min);
tm->tm_hour = bcd2bin(tm->tm_hour);
tm->tm_mday = bcd2bin(tm->tm_mday);
tm->tm_mon = bcd2bin(tm->tm_mon);
tm->tm_year = bcd2bin(tm->tm_year);
/*
* Account for differences between how the RTC uses the values
* and how they are defined in a struct rtc_time;
*/
tm->tm_year += 70;
if (tm->tm_year <= 69)
tm->tm_year += 100;
tm->tm_mon--;
return rtc_valid_tm(tm);
}
static int m48t35_set_time(struct device *dev, struct rtc_time *tm)
{
struct m48t35_priv *priv = dev_get_drvdata(dev);
unsigned char mon, day, hrs, min, sec;
unsigned int yrs;
u8 control;
yrs = tm->tm_year + 1900;
mon = tm->tm_mon + 1; /* tm_mon starts at zero */
day = tm->tm_mday;
hrs = tm->tm_hour;
min = tm->tm_min;
sec = tm->tm_sec;
if (yrs < 1970)
return -EINVAL;
yrs -= 1970;
if (yrs > 255) /* They are unsigned */
return -EINVAL;
if (yrs > 169)
return -EINVAL;
if (yrs >= 100)
yrs -= 100;
sec = bin2bcd(sec);
min = bin2bcd(min);
hrs = bin2bcd(hrs);
day = bin2bcd(day);
mon = bin2bcd(mon);
yrs = bin2bcd(yrs);
spin_lock_irq(&priv->lock);
control = readb(&priv->reg->control);
writeb(control | M48T35_RTC_SET, &priv->reg->control);
writeb(yrs, &priv->reg->year);
writeb(mon, &priv->reg->month);
writeb(day, &priv->reg->date);
writeb(hrs, &priv->reg->hour);
writeb(min, &priv->reg->min);
writeb(sec, &priv->reg->sec);
writeb(control, &priv->reg->control);
spin_unlock_irq(&priv->lock);
return 0;
}
static const struct rtc_class_ops m48t35_ops = {
.read_time = m48t35_read_time,
.set_time = m48t35_set_time,
};
static int m48t35_probe(struct platform_device *pdev)
{
struct resource *res;
struct m48t35_priv *priv;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
priv = devm_kzalloc(&pdev->dev, sizeof(struct m48t35_priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->size = resource_size(res);
/*
* kludge: remove the #ifndef after ioc3 resource
* conflicts are resolved
*/
#ifndef CONFIG_SGI_IP27
if (!devm_request_mem_region(&pdev->dev, res->start, priv->size,
pdev->name))
return -EBUSY;
#endif
priv->baseaddr = res->start;
priv->reg = devm_ioremap(&pdev->dev, priv->baseaddr, priv->size);
if (!priv->reg)
return -ENOMEM;
spin_lock_init(&priv->lock);
platform_set_drvdata(pdev, priv);
priv->rtc = devm_rtc_device_register(&pdev->dev, "m48t35",
&m48t35_ops, THIS_MODULE);
return PTR_ERR_OR_ZERO(priv->rtc);
}
static struct platform_driver m48t35_platform_driver = {
.driver = {
.name = "rtc-m48t35",
},
.probe = m48t35_probe,
};
module_platform_driver(m48t35_platform_driver);
MODULE_AUTHOR("Thomas Bogendoerfer <[email protected]>");
MODULE_DESCRIPTION("M48T35 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_ALIAS("platform:rtc-m48t35");