pty: Coding style and polish
[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/smp_lock.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 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
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 long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
158 {
159         unsigned long flags;
160
161         switch(cmd) {
162                 case RTC_RD_TIME:       /* read the time/date from RTC  */
163                 {
164                         struct rtc_time rtc_tm;
165
166                         memset(&rtc_tm, 0, sizeof (struct rtc_time));
167                         lock_kernel();
168                         get_rtc_time(&rtc_tm);
169                         unlock_kernel();
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                         lock_kernel();
222                         local_irq_save(flags);
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                         unlock_kernel();
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                         lock_kernel();
251                         tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
252                         ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
253                         unlock_kernel();
254                         return 0;
255                 }
256                 default:
257                         return -EINVAL;
258         }
259 }
260
261 int
262 get_rtc_status(char *buf)
263 {
264         char *p;
265         struct rtc_time tm;
266
267         p = buf;
268
269         get_rtc_time(&tm);
270
271         /*
272          * There is no way to tell if the luser has the RTC set for local
273          * time or for Universal Standard Time (GMT). Probably local though.
274          */
275
276         p += sprintf(p,
277                 "rtc_time\t: %02d:%02d:%02d\n"
278                 "rtc_date\t: %04d-%02d-%02d\n",
279                 tm.tm_hour, tm.tm_min, tm.tm_sec,
280                 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
281
282         return  p - buf;
283 }
284
285
286 /* The various file operations we support. */
287
288 static const struct file_operations rtc_fops = {
289         .owner          = THIS_MODULE,
290         .unlocked_ioctl = rtc_ioctl,
291 };
292
293 /* Probe for the chip by writing something to its RAM and try reading it back. */
294
295 #define MAGIC_PATTERN 0x42
296
297 static int __init
298 ds1302_probe(void)
299 {
300         int retval, res, baur;
301
302         baur=(boot_cpu_data.bus_clock/(2*1000*1000));
303
304         printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
305
306         outw(0x0000,(unsigned long)PLD_RTCCR);
307         outw(0x0000,(unsigned long)PLD_RTCRSTODT);
308         outw(baur,(unsigned long)PLD_RTCBAUR);
309
310         /* Try to talk to timekeeper. */
311
312         ds1302_wenable();
313         /* write RAM byte 0 */
314         /* write something magic */
315         out_byte_rtc(0xc0,MAGIC_PATTERN);
316
317         /* read RAM byte 0 */
318         if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
319                 char buf[100];
320                 ds1302_wdisable();
321                 printk("%s: RTC found.\n", ds1302_name);
322                 get_rtc_status(buf);
323                 printk(buf);
324                 retval = 1;
325         } else {
326                 printk("%s: RTC not found.\n", ds1302_name);
327                 retval = 0;
328         }
329
330         return retval;
331 }
332
333
334 /* Just probe for the RTC and register the device to handle the ioctl needed. */
335
336 int __init
337 ds1302_init(void)
338 {
339         if (!ds1302_probe()) {
340                 return -1;
341         }
342         return 0;
343 }
344
345 static int __init ds1302_register(void)
346 {
347         ds1302_init();
348         if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
349                 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
350                        ds1302_name, RTC_MAJOR_NR);
351                 return -1;
352         }
353         return 0;
354 }
355
356 module_init(ds1302_register);