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