Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
[linux-2.6.git] / drivers / char / ds1302.c
1 /*!***************************************************************************
2 *!
3 *! FILE NAME  : ds1302.c
4 *!
5 *! DESCRIPTION: Implements an interface for the DS1302 RTC
6 *!
7 *! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status
8 *!
9 *! ---------------------------------------------------------------------------
10 *!
11 *! (C) Copyright 1999, 2000, 2001  Axis Communications AB, LUND, SWEDEN
12 *!
13 *!***************************************************************************/
14
15
16 #include <linux/fs.h>
17 #include <linux/init.h>
18 #include <linux/mm.h>
19 #include <linux/module.h>
20 #include <linux/miscdevice.h>
21 #include <linux/delay.h>
22 #include <linux/bcd.h>
23 #include <linux/mutex.h>
24 #include <linux/uaccess.h>
25 #include <linux/io.h>
26
27 #include <asm/system.h>
28 #include <asm/rtc.h>
29 #if defined(CONFIG_M32R)
30 #include <asm/m32r.h>
31 #endif
32
33 #define RTC_MAJOR_NR 121 /* local major, change later */
34
35 static DEFINE_MUTEX(rtc_mutex);
36 static const char ds1302_name[] = "ds1302";
37
38 /* Send 8 bits. */
39 static void
40 out_byte_rtc(unsigned int reg_addr, unsigned char x)
41 {
42         //RST H
43         outw(0x0001,(unsigned long)PLD_RTCRSTODT);
44         //write data
45         outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA);
46         //WE
47         outw(0x0002,(unsigned long)PLD_RTCCR);
48         //wait
49         while(inw((unsigned long)PLD_RTCCR));
50
51         //RST L
52         outw(0x0000,(unsigned long)PLD_RTCRSTODT);
53
54 }
55
56 static unsigned char
57 in_byte_rtc(unsigned int reg_addr)
58 {
59         unsigned char retval;
60
61         //RST H
62         outw(0x0001,(unsigned long)PLD_RTCRSTODT);
63         //write data
64         outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA);
65         //RE
66         outw(0x0001,(unsigned long)PLD_RTCCR);
67         //wait
68         while(inw((unsigned long)PLD_RTCCR));
69
70         //read data
71         retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8;
72
73         //RST L
74         outw(0x0000,(unsigned long)PLD_RTCRSTODT);
75
76         return retval;
77 }
78
79 /* Enable writing. */
80
81 static void
82 ds1302_wenable(void)
83 {
84         out_byte_rtc(0x8e,0x00);
85 }
86
87 /* Disable writing. */
88
89 static void
90 ds1302_wdisable(void)
91 {
92         out_byte_rtc(0x8e,0x80);
93 }
94
95
96
97 /* Read a byte from the selected register in the DS1302. */
98
99 unsigned char
100 ds1302_readreg(int reg)
101 {
102         unsigned char x;
103
104         x=in_byte_rtc((0x81 | (reg << 1))); /* read register */
105
106         return x;
107 }
108
109 /* Write a byte to the selected register. */
110
111 void
112 ds1302_writereg(int reg, unsigned char val)
113 {
114         ds1302_wenable();
115         out_byte_rtc((0x80 | (reg << 1)),val);
116         ds1302_wdisable();
117 }
118
119 void
120 get_rtc_time(struct rtc_time *rtc_tm)
121 {
122         unsigned long flags;
123
124         local_irq_save(flags);
125
126         rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
127         rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
128         rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
129         rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
130         rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
131         rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
132
133         local_irq_restore(flags);
134
135         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
136         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
137         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
138         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
139         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
140         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
141
142         /*
143          * Account for differences between how the RTC uses the values
144          * and how they are defined in a struct rtc_time;
145          */
146
147         if (rtc_tm->tm_year <= 69)
148                 rtc_tm->tm_year += 100;
149
150         rtc_tm->tm_mon--;
151 }
152
153 static unsigned char days_in_mo[] =
154     {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
155
156 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
157
158 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
159 {
160         unsigned long flags;
161
162         switch(cmd) {
163                 case RTC_RD_TIME:       /* read the time/date from RTC  */
164                 {
165                         struct rtc_time rtc_tm;
166
167                         memset(&rtc_tm, 0, sizeof (struct rtc_time));
168                         mutex_lock(&rtc_mutex);
169                         get_rtc_time(&rtc_tm);
170                         mutex_unlock(&rtc_mutex);
171                         if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
172                                 return -EFAULT;
173                         return 0;
174                 }
175
176                 case RTC_SET_TIME:      /* set the RTC */
177                 {
178                         struct rtc_time rtc_tm;
179                         unsigned char mon, day, hrs, min, sec, leap_yr;
180                         unsigned int yrs;
181
182                         if (!capable(CAP_SYS_TIME))
183                                 return -EPERM;
184
185                         if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
186                                 return -EFAULT;
187
188                         yrs = rtc_tm.tm_year + 1900;
189                         mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
190                         day = rtc_tm.tm_mday;
191                         hrs = rtc_tm.tm_hour;
192                         min = rtc_tm.tm_min;
193                         sec = rtc_tm.tm_sec;
194
195
196                         if ((yrs < 1970) || (yrs > 2069))
197                                 return -EINVAL;
198
199                         leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
200
201                         if ((mon > 12) || (day == 0))
202                                 return -EINVAL;
203
204                         if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
205                                 return -EINVAL;
206
207                         if ((hrs >= 24) || (min >= 60) || (sec >= 60))
208                                 return -EINVAL;
209
210                         if (yrs >= 2000)
211                                 yrs -= 2000;    /* RTC (0, 1, ... 69) */
212                         else
213                                 yrs -= 1900;    /* RTC (70, 71, ... 99) */
214
215                         sec = bin2bcd(sec);
216                         min = bin2bcd(min);
217                         hrs = bin2bcd(hrs);
218                         day = bin2bcd(day);
219                         mon = bin2bcd(mon);
220                         yrs = bin2bcd(yrs);
221
222                         mutex_lock(&rtc_mutex);
223                         local_irq_save(flags);
224                         CMOS_WRITE(yrs, RTC_YEAR);
225                         CMOS_WRITE(mon, RTC_MONTH);
226                         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
227                         CMOS_WRITE(hrs, RTC_HOURS);
228                         CMOS_WRITE(min, RTC_MINUTES);
229                         CMOS_WRITE(sec, RTC_SECONDS);
230                         local_irq_restore(flags);
231                         mutex_unlock(&rtc_mutex);
232
233                         /* Notice that at this point, the RTC is updated but
234                          * the kernel is still running with the old time.
235                          * You need to set that separately with settimeofday
236                          * or adjtimex.
237                          */
238                         return 0;
239                 }
240
241                 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
242                 {
243                         int tcs_val;
244
245                         if (!capable(CAP_SYS_TIME))
246                                 return -EPERM;
247
248                         if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
249                                 return -EFAULT;
250
251                         mutex_lock(&rtc_mutex);
252                         tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
253                         ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
254                         mutex_unlock(&rtc_mutex);
255                         return 0;
256                 }
257                 default:
258                         return -EINVAL;
259         }
260 }
261
262 int
263 get_rtc_status(char *buf)
264 {
265         char *p;
266         struct rtc_time tm;
267
268         p = buf;
269
270         get_rtc_time(&tm);
271
272         /*
273          * There is no way to tell if the luser has the RTC set for local
274          * time or for Universal Standard Time (GMT). Probably local though.
275          */
276
277         p += sprintf(p,
278                 "rtc_time\t: %02d:%02d:%02d\n"
279                 "rtc_date\t: %04d-%02d-%02d\n",
280                 tm.tm_hour, tm.tm_min, tm.tm_sec,
281                 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
282
283         return  p - buf;
284 }
285
286
287 /* The various file operations we support. */
288
289 static const struct file_operations rtc_fops = {
290         .owner          = THIS_MODULE,
291         .unlocked_ioctl = rtc_ioctl,
292         .llseek         = noop_llseek,
293 };
294
295 /* Probe for the chip by writing something to its RAM and try reading it back. */
296
297 #define MAGIC_PATTERN 0x42
298
299 static int __init
300 ds1302_probe(void)
301 {
302         int retval, res, baur;
303
304         baur=(boot_cpu_data.bus_clock/(2*1000*1000));
305
306         printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
307
308         outw(0x0000,(unsigned long)PLD_RTCCR);
309         outw(0x0000,(unsigned long)PLD_RTCRSTODT);
310         outw(baur,(unsigned long)PLD_RTCBAUR);
311
312         /* Try to talk to timekeeper. */
313
314         ds1302_wenable();
315         /* write RAM byte 0 */
316         /* write something magic */
317         out_byte_rtc(0xc0,MAGIC_PATTERN);
318
319         /* read RAM byte 0 */
320         if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
321                 char buf[100];
322                 ds1302_wdisable();
323                 printk("%s: RTC found.\n", ds1302_name);
324                 get_rtc_status(buf);
325                 printk(buf);
326                 retval = 1;
327         } else {
328                 printk("%s: RTC not found.\n", ds1302_name);
329                 retval = 0;
330         }
331
332         return retval;
333 }
334
335
336 /* Just probe for the RTC and register the device to handle the ioctl needed. */
337
338 int __init
339 ds1302_init(void)
340 {
341         if (!ds1302_probe()) {
342                 return -1;
343         }
344         return 0;
345 }
346
347 static int __init ds1302_register(void)
348 {
349         ds1302_init();
350         if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
351                 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
352                        ds1302_name, RTC_MAJOR_NR);
353                 return -1;
354         }
355         return 0;
356 }
357
358 module_init(ds1302_register);