1 /*!***************************************************************************
3 *! FILE NAME : ds1302.c
5 *! DESCRIPTION: Implements an interface for the DS1302 RTC
7 *! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status
9 *! ---------------------------------------------------------------------------
11 *! (C) Copyright 1999, 2000, 2001 Axis Communications AB, LUND, SWEDEN
13 *!***************************************************************************/
17 #include <linux/init.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>
28 #if defined(CONFIG_M32R)
32 #define RTC_MAJOR_NR 121 /* local major, change later */
34 static DEFINE_MUTEX(rtc_mutex
);
35 static const char ds1302_name
[] = "ds1302";
39 out_byte_rtc(unsigned int reg_addr
, unsigned char x
)
42 outw(0x0001,(unsigned long)PLD_RTCRSTODT
);
44 outw(((x
<<8)|(reg_addr
&0xff)),(unsigned long)PLD_RTCWRDATA
);
46 outw(0x0002,(unsigned long)PLD_RTCCR
);
48 while(inw((unsigned long)PLD_RTCCR
));
51 outw(0x0000,(unsigned long)PLD_RTCRSTODT
);
56 in_byte_rtc(unsigned int reg_addr
)
61 outw(0x0001,(unsigned long)PLD_RTCRSTODT
);
63 outw((reg_addr
&0xff),(unsigned long)PLD_RTCRDDATA
);
65 outw(0x0001,(unsigned long)PLD_RTCCR
);
67 while(inw((unsigned long)PLD_RTCCR
));
70 retval
=(inw((unsigned long)PLD_RTCRDDATA
) & 0xff00)>>8;
73 outw(0x0000,(unsigned long)PLD_RTCRSTODT
);
83 out_byte_rtc(0x8e,0x00);
86 /* Disable writing. */
91 out_byte_rtc(0x8e,0x80);
96 /* Read a byte from the selected register in the DS1302. */
99 ds1302_readreg(int reg
)
103 x
=in_byte_rtc((0x81 | (reg
<< 1))); /* read register */
108 /* Write a byte to the selected register. */
111 ds1302_writereg(int reg
, unsigned char val
)
114 out_byte_rtc((0x80 | (reg
<< 1)),val
);
119 get_rtc_time(struct rtc_time
*rtc_tm
)
123 local_irq_save(flags
);
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
);
132 local_irq_restore(flags
);
134 rtc_tm
->tm_sec
= bcd2bin(rtc_tm
->tm_sec
);
135 rtc_tm
->tm_min
= bcd2bin(rtc_tm
->tm_min
);
136 rtc_tm
->tm_hour
= bcd2bin(rtc_tm
->tm_hour
);
137 rtc_tm
->tm_mday
= bcd2bin(rtc_tm
->tm_mday
);
138 rtc_tm
->tm_mon
= bcd2bin(rtc_tm
->tm_mon
);
139 rtc_tm
->tm_year
= bcd2bin(rtc_tm
->tm_year
);
142 * Account for differences between how the RTC uses the values
143 * and how they are defined in a struct rtc_time;
146 if (rtc_tm
->tm_year
<= 69)
147 rtc_tm
->tm_year
+= 100;
152 static unsigned char days_in_mo
[] =
153 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
155 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
157 static long rtc_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
162 case RTC_RD_TIME
: /* read the time/date from RTC */
164 struct rtc_time rtc_tm
;
166 memset(&rtc_tm
, 0, sizeof (struct rtc_time
));
167 mutex_lock(&rtc_mutex
);
168 get_rtc_time(&rtc_tm
);
169 mutex_unlock(&rtc_mutex
);
170 if (copy_to_user((struct rtc_time
*)arg
, &rtc_tm
, sizeof(struct rtc_time
)))
175 case RTC_SET_TIME
: /* set the RTC */
177 struct rtc_time rtc_tm
;
178 unsigned char mon
, day
, hrs
, min
, sec
, leap_yr
;
181 if (!capable(CAP_SYS_TIME
))
184 if (copy_from_user(&rtc_tm
, (struct rtc_time
*)arg
, sizeof(struct rtc_time
)))
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
;
195 if ((yrs
< 1970) || (yrs
> 2069))
198 leap_yr
= ((!(yrs
% 4) && (yrs
% 100)) || !(yrs
% 400));
200 if ((mon
> 12) || (day
== 0))
203 if (day
> (days_in_mo
[mon
] + ((mon
== 2) && leap_yr
)))
206 if ((hrs
>= 24) || (min
>= 60) || (sec
>= 60))
210 yrs
-= 2000; /* RTC (0, 1, ... 69) */
212 yrs
-= 1900; /* RTC (70, 71, ... 99) */
221 mutex_lock(&rtc_mutex
);
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 mutex_unlock(&rtc_mutex
);
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
240 case RTC_SET_CHARGE
: /* set the RTC TRICKLE CHARGE register */
244 if (!capable(CAP_SYS_TIME
))
247 if(copy_from_user(&tcs_val
, (int*)arg
, sizeof(int)))
250 mutex_lock(&rtc_mutex
);
251 tcs_val
= RTC_TCR_PATTERN
| (tcs_val
& 0x0F);
252 ds1302_writereg(RTC_TRICKLECHARGER
, tcs_val
);
253 mutex_unlock(&rtc_mutex
);
262 get_rtc_status(char *buf
)
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.
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
);
286 /* The various file operations we support. */
288 static const struct file_operations rtc_fops
= {
289 .owner
= THIS_MODULE
,
290 .unlocked_ioctl
= rtc_ioctl
,
291 .llseek
= noop_llseek
,
294 /* Probe for the chip by writing something to its RAM and try reading it back. */
296 #define MAGIC_PATTERN 0x42
301 int retval
, res
, baur
;
303 baur
=(boot_cpu_data
.bus_clock
/(2*1000*1000));
305 printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name
,baur
);
307 outw(0x0000,(unsigned long)PLD_RTCCR
);
308 outw(0x0000,(unsigned long)PLD_RTCRSTODT
);
309 outw(baur
,(unsigned long)PLD_RTCBAUR
);
311 /* Try to talk to timekeeper. */
314 /* write RAM byte 0 */
315 /* write something magic */
316 out_byte_rtc(0xc0,MAGIC_PATTERN
);
318 /* read RAM byte 0 */
319 if((res
= in_byte_rtc(0xc1)) == MAGIC_PATTERN
) {
322 printk("%s: RTC found.\n", ds1302_name
);
327 printk("%s: RTC not found.\n", ds1302_name
);
335 /* Just probe for the RTC and register the device to handle the ioctl needed. */
340 if (!ds1302_probe()) {
346 static int __init
ds1302_register(void)
349 if (register_chrdev(RTC_MAJOR_NR
, ds1302_name
, &rtc_fops
)) {
350 printk(KERN_INFO
"%s: unable to get major %d for rtc\n",
351 ds1302_name
, RTC_MAJOR_NR
);
357 module_init(ds1302_register
);
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