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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); |