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1da177e4 LT |
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 | ||
1da177e4 LT |
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); | |
1da177e4 LT |
123 | |
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 | ||
151 | static 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 | ||
156 | static int | |
157 | rtc_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); | |
1da177e4 LT |
221 | 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 | ||
256 | int | |
257 | get_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 | ||
62322d25 | 283 | static const struct file_operations rtc_fops = { |
1da177e4 LT |
284 | .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 | ||
292 | static int __init | |
293 | ds1302_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 | ||
331 | int __init | |
332 | ds1302_init(void) | |
333 | { | |
334 | if (!ds1302_probe()) { | |
335 | return -1; | |
336 | } | |
337 | return 0; | |
338 | } | |
339 | ||
340 | static 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 | ||
351 | module_init(ds1302_register); |