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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*!***************************************************************************
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
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
34static const char ds1302_name[] = "ds1302";
35
36/* Send 8 bits. */
37static void
38out_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
54static unsigned char
55in_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
79static void
80ds1302_wenable(void)
81{
82 out_byte_rtc(0x8e,0x00);
83}
84
85/* Disable writing. */
86
87static void
88ds1302_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
97unsigned char
98ds1302_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
109void
110ds1302_writereg(int reg, unsigned char val)
111{
112 ds1302_wenable();
113 out_byte_rtc((0x80 | (reg << 1)),val);
114 ds1302_wdisable();
115}
116
117void
118get_rtc_time(struct rtc_time *rtc_tm)
119{
120 unsigned long flags;
121
122 local_irq_save(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
124 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
125 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
126 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
127 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
128 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
129 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
130
131 local_irq_restore(flags);
132
133 BCD_TO_BIN(rtc_tm->tm_sec);
134 BCD_TO_BIN(rtc_tm->tm_min);
135 BCD_TO_BIN(rtc_tm->tm_hour);
136 BCD_TO_BIN(rtc_tm->tm_mday);
137 BCD_TO_BIN(rtc_tm->tm_mon);
138 BCD_TO_BIN(rtc_tm->tm_year);
139
140 /*
141 * Account for differences between how the RTC uses the values
142 * and how they are defined in a struct rtc_time;
143 */
144
145 if (rtc_tm->tm_year <= 69)
146 rtc_tm->tm_year += 100;
147
148 rtc_tm->tm_mon--;
149}
150
151static unsigned char days_in_mo[] =
152 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
153
154/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
155
156static int
157rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
158 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 get_rtc_time(&rtc_tm);
169 if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
170 return -EFAULT;
171 return 0;
172 }
173
174 case RTC_SET_TIME: /* set the RTC */
175 {
176 struct rtc_time rtc_tm;
177 unsigned char mon, day, hrs, min, sec, leap_yr;
178 unsigned int yrs;
179
180 if (!capable(CAP_SYS_TIME))
181 return -EPERM;
182
183 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
184 return -EFAULT;
185
186 yrs = rtc_tm.tm_year + 1900;
187 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
188 day = rtc_tm.tm_mday;
189 hrs = rtc_tm.tm_hour;
190 min = rtc_tm.tm_min;
191 sec = rtc_tm.tm_sec;
192
193
194 if ((yrs < 1970) || (yrs > 2069))
195 return -EINVAL;
196
197 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
198
199 if ((mon > 12) || (day == 0))
200 return -EINVAL;
201
202 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
203 return -EINVAL;
204
205 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
206 return -EINVAL;
207
208 if (yrs >= 2000)
209 yrs -= 2000; /* RTC (0, 1, ... 69) */
210 else
211 yrs -= 1900; /* RTC (70, 71, ... 99) */
212
213 BIN_TO_BCD(sec);
214 BIN_TO_BCD(min);
215 BIN_TO_BCD(hrs);
216 BIN_TO_BCD(day);
217 BIN_TO_BCD(mon);
218 BIN_TO_BCD(yrs);
219
220 local_irq_save(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 CMOS_WRITE(yrs, RTC_YEAR);
222 CMOS_WRITE(mon, RTC_MONTH);
223 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
224 CMOS_WRITE(hrs, RTC_HOURS);
225 CMOS_WRITE(min, RTC_MINUTES);
226 CMOS_WRITE(sec, RTC_SECONDS);
227 local_irq_restore(flags);
228
229 /* Notice that at this point, the RTC is updated but
230 * the kernel is still running with the old time.
231 * You need to set that separately with settimeofday
232 * or adjtimex.
233 */
234 return 0;
235 }
236
237 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
238 {
239 int tcs_val;
240
241 if (!capable(CAP_SYS_TIME))
242 return -EPERM;
243
244 if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
245 return -EFAULT;
246
247 tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
248 ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
249 return 0;
250 }
251 default:
252 return -EINVAL;
253 }
254}
255
256int
257get_rtc_status(char *buf)
258{
259 char *p;
260 struct rtc_time tm;
261
262 p = buf;
263
264 get_rtc_time(&tm);
265
266 /*
267 * There is no way to tell if the luser has the RTC set for local
268 * time or for Universal Standard Time (GMT). Probably local though.
269 */
270
271 p += sprintf(p,
272 "rtc_time\t: %02d:%02d:%02d\n"
273 "rtc_date\t: %04d-%02d-%02d\n",
274 tm.tm_hour, tm.tm_min, tm.tm_sec,
275 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
276
277 return p - buf;
278}
279
280
281/* The various file operations we support. */
282
Arjan van de Ven62322d22006-07-03 00:24:21 -0700283static const struct file_operations rtc_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 .owner = THIS_MODULE,
285 .ioctl = rtc_ioctl,
286};
287
288/* Probe for the chip by writing something to its RAM and try reading it back. */
289
290#define MAGIC_PATTERN 0x42
291
292static int __init
293ds1302_probe(void)
294{
295 int retval, res, baur;
296
297 baur=(boot_cpu_data.bus_clock/(2*1000*1000));
298
299 printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
300
301 outw(0x0000,(unsigned long)PLD_RTCCR);
302 outw(0x0000,(unsigned long)PLD_RTCRSTODT);
303 outw(baur,(unsigned long)PLD_RTCBAUR);
304
305 /* Try to talk to timekeeper. */
306
307 ds1302_wenable();
308 /* write RAM byte 0 */
309 /* write something magic */
310 out_byte_rtc(0xc0,MAGIC_PATTERN);
311
312 /* read RAM byte 0 */
313 if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
314 char buf[100];
315 ds1302_wdisable();
316 printk("%s: RTC found.\n", ds1302_name);
317 get_rtc_status(buf);
318 printk(buf);
319 retval = 1;
320 } else {
321 printk("%s: RTC not found.\n", ds1302_name);
322 retval = 0;
323 }
324
325 return retval;
326}
327
328
329/* Just probe for the RTC and register the device to handle the ioctl needed. */
330
331int __init
332ds1302_init(void)
333{
334 if (!ds1302_probe()) {
335 return -1;
336 }
337 return 0;
338}
339
340static int __init ds1302_register(void)
341{
342 ds1302_init();
343 if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
344 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
345 ds1302_name, RTC_MAJOR_NR);
346 return -1;
347 }
348 return 0;
349}
350
351module_init(ds1302_register);