1 /*
2 * Linux/PowerPC Real Time Clock Driver
3 *
4 * heavily based on:
5 * Linux/SPARC Real Time Clock Driver
6 * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
7 *
8 * This is a little driver that lets a user-level program access
9 * the PPC clocks chip. It is no use unless you
10 * use the modified clock utility.
11 *
12 * Get the modified clock utility from:
13 * ftp://vger.rutgers.edu/pub/linux/Sparc/userland/clock.c
14 */
15
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/errno.h>
19 #include <linux/miscdevice.h>
20 #include <linux/slab.h>
21 #include <linux/fcntl.h>
22 #include <linux/poll.h>
23 #include <linux/init.h>
24 #include <linux/mc146818rtc.h>
25 #include <asm/system.h>
26 #include <asm/uaccess.h>
27 #include <asm/machdep.h>
28
29 #include <asm/time.h>
30
31 static int rtc_busy = 0;
32
33 /* Retrieve the current date and time from the real time clock. */
get_rtc_time(struct rtc_time * t)34 void get_rtc_time(struct rtc_time *t)
35 {
36 unsigned long nowtime;
37
38 nowtime = (ppc_md.get_rtc_time)();
39
40 to_tm(nowtime, t);
41
42 t->tm_year -= 1900;
43 t->tm_mon -= 1; /* Make sure userland has a 0-based month */
44 }
45
46 /* Set the current date and time in the real time clock. */
set_rtc_time(struct rtc_time * t)47 void set_rtc_time(struct rtc_time *t)
48 {
49 unsigned long nowtime;
50
51 nowtime = mktime(t->tm_year+1900, t->tm_mon+1, t->tm_mday,
52 t->tm_hour, t->tm_min, t->tm_sec);
53
54 (ppc_md.set_rtc_time)(nowtime);
55 }
56
rtc_ioctl(struct inode * inode,struct file * file,unsigned int cmd,unsigned long arg)57 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
58 unsigned long arg)
59 {
60 struct rtc_time rtc_tm;
61
62 switch (cmd)
63 {
64 case RTC_RD_TIME:
65 if (ppc_md.get_rtc_time)
66 {
67 memset(&rtc_tm, 0, sizeof(struct rtc_time));
68 get_rtc_time(&rtc_tm);
69
70 if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
71 return -EFAULT;
72
73 return 0;
74 }
75 else
76 return -EINVAL;
77
78 case RTC_SET_TIME:
79 if (!capable(CAP_SYS_TIME))
80 return -EPERM;
81
82 if (ppc_md.set_rtc_time)
83 {
84 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
85 return -EFAULT;
86
87 set_rtc_time(&rtc_tm);
88
89 return 0;
90 }
91 else
92 return -EINVAL;
93
94 default:
95 return -EINVAL;
96 }
97 }
98
rtc_open(struct inode * inode,struct file * file)99 static int rtc_open(struct inode *inode, struct file *file)
100 {
101 if (rtc_busy)
102 return -EBUSY;
103
104 rtc_busy = 1;
105
106 MOD_INC_USE_COUNT;
107
108 return 0;
109 }
110
rtc_release(struct inode * inode,struct file * file)111 static int rtc_release(struct inode *inode, struct file *file)
112 {
113 MOD_DEC_USE_COUNT;
114 rtc_busy = 0;
115 return 0;
116 }
117
118 static struct file_operations rtc_fops = {
119 owner: THIS_MODULE,
120 llseek: no_llseek,
121 ioctl: rtc_ioctl,
122 open: rtc_open,
123 release: rtc_release
124 };
125
126 static struct miscdevice rtc_dev = { RTC_MINOR, "rtc", &rtc_fops };
127
128 EXPORT_NO_SYMBOLS;
129
rtc_init(void)130 static int __init rtc_init(void)
131 {
132 int error;
133
134 error = misc_register(&rtc_dev);
135 if (error) {
136 printk(KERN_ERR "rtc: unable to get misc minor\n");
137 return error;
138 }
139
140 return 0;
141 }
142
rtc_exit(void)143 static void __exit rtc_exit(void)
144 {
145 misc_deregister(&rtc_dev);
146 }
147
148 module_init(rtc_init);
149 module_exit(rtc_exit);
150 MODULE_LICENSE("GPL");
151