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[linux-2.6] / 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 #include <linux/config.h>
16
17 #include <linux/fs.h>
18 #include <linux/init.h>
19 #include <linux/mm.h>
20 #include <linux/module.h>
21 #include <linux/miscdevice.h>
22 #include <linux/delay.h>
23 #include <linux/bcd.h>
24
25 #include <asm/uaccess.h>
26 #include <asm/system.h>
27 #include <asm/io.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 const char ds1302_name[] = "ds1302";
36
37 /* Send 8 bits. */
38 static void
39 out_byte_rtc(unsigned int reg_addr, unsigned char x)
40 {
41         //RST H
42         outw(0x0001,(unsigned long)PLD_RTCRSTODT);
43         //write data
44         outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA);
45         //WE
46         outw(0x0002,(unsigned long)PLD_RTCCR);
47         //wait
48         while(inw((unsigned long)PLD_RTCCR));
49
50         //RST L
51         outw(0x0000,(unsigned long)PLD_RTCRSTODT);
52
53 }
54
55 static unsigned char
56 in_byte_rtc(unsigned int reg_addr)
57 {
58         unsigned char retval;
59
60         //RST H
61         outw(0x0001,(unsigned long)PLD_RTCRSTODT);
62         //write data
63         outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA);
64         //RE
65         outw(0x0001,(unsigned long)PLD_RTCCR);
66         //wait
67         while(inw((unsigned long)PLD_RTCCR));
68
69         //read data
70         retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8;
71
72         //RST L
73         outw(0x0000,(unsigned long)PLD_RTCRSTODT);
74
75         return retval;
76 }
77
78 /* Enable writing. */
79
80 static void
81 ds1302_wenable(void)
82 {
83         out_byte_rtc(0x8e,0x00);
84 }
85
86 /* Disable writing. */
87
88 static void
89 ds1302_wdisable(void)
90 {
91         out_byte_rtc(0x8e,0x80);
92 }
93
94
95
96 /* Read a byte from the selected register in the DS1302. */
97
98 unsigned char
99 ds1302_readreg(int reg)
100 {
101         unsigned char x;
102
103         x=in_byte_rtc((0x81 | (reg << 1))); /* read register */
104
105         return x;
106 }
107
108 /* Write a byte to the selected register. */
109
110 void
111 ds1302_writereg(int reg, unsigned char val)
112 {
113         ds1302_wenable();
114         out_byte_rtc((0x80 | (reg << 1)),val);
115         ds1302_wdisable();
116 }
117
118 void
119 get_rtc_time(struct rtc_time *rtc_tm)
120 {
121         unsigned long flags;
122
123         local_irq_save(flags);
124         local_irq_disable();
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         BCD_TO_BIN(rtc_tm->tm_sec);
136         BCD_TO_BIN(rtc_tm->tm_min);
137         BCD_TO_BIN(rtc_tm->tm_hour);
138         BCD_TO_BIN(rtc_tm->tm_mday);
139         BCD_TO_BIN(rtc_tm->tm_mon);
140         BCD_TO_BIN(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 int
159 rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
160           unsigned long arg)
161 {
162         unsigned long flags;
163
164         switch(cmd) {
165                 case RTC_RD_TIME:       /* read the time/date from RTC  */
166                 {
167                         struct rtc_time rtc_tm;
168
169                         memset(&rtc_tm, 0, sizeof (struct rtc_time));
170                         get_rtc_time(&rtc_tm);
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                         BIN_TO_BCD(sec);
216                         BIN_TO_BCD(min);
217                         BIN_TO_BCD(hrs);
218                         BIN_TO_BCD(day);
219                         BIN_TO_BCD(mon);
220                         BIN_TO_BCD(yrs);
221
222                         local_irq_save(flags);
223                         local_irq_disable();
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
232                         /* Notice that at this point, the RTC is updated but
233                          * the kernel is still running with the old time.
234                          * You need to set that separately with settimeofday
235                          * or adjtimex.
236                          */
237                         return 0;
238                 }
239
240                 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
241                 {
242                         int tcs_val;
243
244                         if (!capable(CAP_SYS_TIME))
245                                 return -EPERM;
246
247                         if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
248                                 return -EFAULT;
249
250                         tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
251                         ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
252                         return 0;
253                 }
254                 default:
255                         return -EINVAL;
256         }
257 }
258
259 int
260 get_rtc_status(char *buf)
261 {
262         char *p;
263         struct rtc_time tm;
264
265         p = buf;
266
267         get_rtc_time(&tm);
268
269         /*
270          * There is no way to tell if the luser has the RTC set for local
271          * time or for Universal Standard Time (GMT). Probably local though.
272          */
273
274         p += sprintf(p,
275                 "rtc_time\t: %02d:%02d:%02d\n"
276                 "rtc_date\t: %04d-%02d-%02d\n",
277                 tm.tm_hour, tm.tm_min, tm.tm_sec,
278                 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
279
280         return  p - buf;
281 }
282
283
284 /* The various file operations we support. */
285
286 static struct file_operations rtc_fops = {
287         .owner          = THIS_MODULE,
288         .ioctl          = rtc_ioctl,
289 };
290
291 /* Probe for the chip by writing something to its RAM and try reading it back. */
292
293 #define MAGIC_PATTERN 0x42
294
295 static int __init
296 ds1302_probe(void)
297 {
298         int retval, res, baur;
299
300         baur=(boot_cpu_data.bus_clock/(2*1000*1000));
301
302         printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
303
304         outw(0x0000,(unsigned long)PLD_RTCCR);
305         outw(0x0000,(unsigned long)PLD_RTCRSTODT);
306         outw(baur,(unsigned long)PLD_RTCBAUR);
307
308         /* Try to talk to timekeeper. */
309
310         ds1302_wenable();
311         /* write RAM byte 0 */
312         /* write something magic */
313         out_byte_rtc(0xc0,MAGIC_PATTERN);
314
315         /* read RAM byte 0 */
316         if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
317                 char buf[100];
318                 ds1302_wdisable();
319                 printk("%s: RTC found.\n", ds1302_name);
320                 get_rtc_status(buf);
321                 printk(buf);
322                 retval = 1;
323         } else {
324                 printk("%s: RTC not found.\n", ds1302_name);
325                 retval = 0;
326         }
327
328         return retval;
329 }
330
331
332 /* Just probe for the RTC and register the device to handle the ioctl needed. */
333
334 int __init
335 ds1302_init(void)
336 {
337         if (!ds1302_probe()) {
338                 return -1;
339         }
340         return 0;
341 }
342
343 static int __init ds1302_register(void)
344 {
345         ds1302_init();
346         if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
347                 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
348                        ds1302_name, RTC_MAJOR_NR);
349                 return -1;
350         }
351         return 0;
352 }
353
354 module_init(ds1302_register);