2 x1205 - an 12c driver for the Xicor X1205 RTC
3 Copyright 2004 Karen Spearel
5 please send all reports to:
6 kas11 at tampabay dot rr dot com
8 based on linux/drivers/acron/char/pcf8583.h
9 Copyright (C) 2000 Russell King
11 This program is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 2 of the License, or
14 (at your option) any later version.
16 This program is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
21 You should have received a copy of the GNU General Public License
22 along with this program; if not, write to the Free Software
23 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 * i2c_adapter is the structure used to identify a physical i2c bus along
28 * with the access algorithms necessary to access it.
32 unsigned int id; == is algo->id | hwdep.struct->id, for registered values see below
34 struct i2c_algorithm *algo; the algorithm to access the bus
37 --- administration stuff.
38 int (*client_register)(struct i2c_client *);
39 int (*client_unregister)(struct i2c_client *);
41 data fields that are valid for all devices
42 struct semaphore bus_lock;
43 struct semaphore clist_lock;
47 struct device dev; the adapter device
48 struct class_device class_dev; the class device
51 No need to set this when you initialize the adapter
53 #endif def CONFIG_PROC_FS
56 struct list_head clients;
57 struct list_head list;
58 char name[I2C_NAME_SIZE];
59 struct completion dev_released;
60 struct completion class_dev_released;
65 /*========== Driver for the X1205 on the Linksys NSLU2 ==================*/
67 #include <linux/init.h>
68 #include <linux/i2c.h>
69 #include <linux/slab.h>
70 #include <linux/string.h>
71 #include <linux/errno.h>
72 #include <linux/bcd.h>
73 #include <linux/rtc.h>
75 #include <linux/proc_fs.h>
76 #include <linux/miscdevice.h>
77 #include <linux/device.h>
78 #include <asm/uaccess.h>
79 #include <asm/system.h>
80 #include <linux/moduleparam.h>
82 #define RTC_GETDATETIME 0
84 #define RTC_SETDATETIME 2
86 #define I2C_M_WR 0 // just for consistancy
88 // offsets into read buf - add 2 for write buf
98 #define X1205_I2C_BUS_ADDR 0x6f // hardwired into x1205
99 #define X1205_ALM0_BASE 0x00 // Base address of the ALM0
100 #define X1205_CCR_BASE 0x30 // Base address of the CCR
101 #define X1205_SR_ADDR 0x3f // Status Register
102 #define X1205_SR_WEL 0x02 // Write Enable Latch bit
103 #define X1205_SR_RWEL 0x04 // Register Write Enable Bit
104 #define X1205_MILBIT 0x80 // this bit set in ccr.hour for 24 hr mode
107 #define RTC_DATETOO 1
109 // comment out next line is your x1205 can't do page writes
110 //#define X1205PAGEWRITE 1
111 #ifdef X1205PAGEWRITE
112 #define DRIVERNAME "Xicor x1205 RTC Driver v0.9.3.3"
114 #define DRIVERNAME "Xicor x1205 RTC Dvr v0.9.3.3NPW"
117 #define DEBUG KERN_DEBUG
118 /* This, if defined to 1, turns on a lot of debugging meessages. */
120 #define x1205_debug(args) printk args
122 #define x1205_debug(args) ((void)0)
126 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm, u8 reg_base);
127 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, int datetoo, u8 reg_base);
128 static int x1205_attach(struct i2c_adapter *adapter);
129 static int x1205_detach(struct i2c_client *client);
130 static int x1205_validate_tm(struct rtc_time *tm, int datetoo);
131 static int x1205_command(struct i2c_client *client, unsigned int cmd, void *arg);
132 static int x1205_sync_rtc(void);
133 static int x1205_read(struct file *file, char *buf, size_t count, loff_t *ptr);
134 static int x1205_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg);
135 static int x1205_read_proc(char *buf, char **start, off_t off, int len, int *eof, void *data);
137 static struct i2c_driver x1205_driver = {
138 .owner = THIS_MODULE,
140 .id = I2C_DRIVERID_X1205,
141 .flags = I2C_DF_NOTIFY,
142 .attach_adapter = &x1205_attach, //we don't need to probe...x1205 is hardwired @ 0x6f
143 .detach_client = &x1205_detach,
144 .command = &x1205_command, //this prolly never gets called...used internally tho
147 static struct i2c_client x1205_i2c_client = {
148 .id = I2C_DRIVERID_X1205,
150 .addr = X1205_I2C_BUS_ADDR, // chip address - NOTE: 7bit
151 .adapter = NULL, // the adapter we sit on assigned in attach
152 .driver = &x1205_driver, // and our access routines
153 .usage_count = 0, // How many accesses currently to this client
154 .dev = {}, // the device structure
160 static struct file_operations rtc_fops = {
166 static struct miscdevice x1205_miscdev = {
171 extern int (*set_rtc)(void);
172 static unsigned epoch = 1900; //coresponds to year 0
173 static unsigned rtc_epoch = 2000;
174 static const unsigned char days_in_mo[] =
175 {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
177 //===================================CODE======================================
178 // in the routines that deal directly with the x1205 hardware, we use
179 // rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
180 // Epoch is inited as 2000. Time is set to UT
181 //=============================================================================
182 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm, u8 reg_base)
184 static unsigned char addr[2] = { 0,} ;
185 unsigned char buf[8];
186 struct i2c_msg msgs[2] = {
187 { client->addr, I2C_M_WR, 2, addr }, //msg 1 = send base address
188 { client->addr, I2C_M_RD, 8, buf }, //msg 2 = read sequential data
191 if ((i2c_transfer(client->adapter, msgs, 2)) == 2) { //did we read 2 messages?
192 x1205_debug((KERN_DEBUG "raw x1205 read data - sec-%02x min-%02x hr-%02x mday-%02x mon-%02x year-%02x wday-%02x y2k-%02x\n",
193 buf[0],buf[1],buf[2],buf[3],buf[4],buf[5],buf[6], buf[7]));
194 tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
195 tm->tm_min = BCD2BIN(buf[CCR_MIN]);
196 buf[CCR_HOUR] &= ~X1205_MILBIT;
197 tm->tm_hour = BCD2BIN(buf[CCR_HOUR]); //hr is 0-23
198 tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
199 tm->tm_mon = BCD2BIN(buf[CCR_MONTH]);
200 rtc_epoch = BCD2BIN(buf[CCR_Y2K]) * 100;
201 tm->tm_year = BCD2BIN(buf[CCR_YEAR]) + rtc_epoch - epoch;
202 tm->tm_wday = buf[CCR_WDAY];
203 x1205_debug((KERN_DEBUG "rtc_time output data - sec-%02d min-%02d hr-%02d mday-%02d mon-%02d year-%02d wday-%02d epoch-%d rtc_epoch-%d\n",
204 tm->tm_sec,tm->tm_min,tm->tm_hour,tm->tm_mday,tm->tm_mon,tm->tm_year,tm->tm_wday,epoch, rtc_epoch));
206 printk(KERN_DEBUG "i2c_transfer Read Error\n");
212 // x1205pagewrite allows writing a block of registers in msg3 even though the x1205 says
213 // nothing about this in its spec.
214 // it needs more testing as it is possible some x1205s are actually not-completely-
215 // functional x1226s and there is a reason for the multiple write to not be in the spec.
216 // anyhow, it is enabled for the time being...and we even push out luck by sending 10 bytes
218 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, int datetoo, u8 reg_base)
220 static unsigned char wel[3] = { 0, X1205_SR_ADDR, X1205_SR_WEL };
221 static unsigned char rwel[3] = { 0, X1205_SR_ADDR, X1205_SR_WEL | X1205_SR_RWEL };
222 static unsigned char diswe[3] = { 0, X1205_SR_ADDR, 0 };
224 #ifdef X1205PAGEWRITE
226 static unsigned char buf[10] = { 0, X1205_CCR_BASE, };
227 struct i2c_msg msgs[4] = {
228 { client->addr, I2C_M_WR, 3, wel }, //msg 1 = write WEL to to ccr sr
229 { client->addr, I2C_M_WR, 3, rwel }, //msg 2 = write RWEL to ccr sr
230 { client->addr, I2C_M_WR, 10, buf }, //msg 3 = write ccr base addr +seq data
231 { client->addr, I2C_M_WR, 3, diswe }, //msg 4 = 0 to ccr sr to disable writes
234 msgs[2].len = 5; // 5 bytes + addr to set time only
236 buf[CCR_SEC+2] = BIN2BCD(tm->tm_sec);
237 buf[CCR_MIN+2] = BIN2BCD(tm->tm_min);
238 buf[CCR_HOUR+2] = BIN2BCD(tm->tm_hour) | X1205_MILBIT; // set 24 hour format
240 buf[CCR_MDAY+2] = BIN2BCD(tm->tm_mday);
241 buf[CCR_MONTH+2] = BIN2BCD(tm->tm_mon); // input is 0-11
242 buf[CCR_YEAR+2] = BIN2BCD((tm->tm_year + epoch - rtc_epoch)); // input is yrs since 1900
243 buf[CCR_WDAY+2] = tm->tm_wday & 7;
244 buf[CCR_Y2K+2] = BIN2BCD((rtc_epoch/100));
245 msgs[2].len += 5; //5 more bytes to set date
247 x1205_debug((KERN_DEBUG "rtc_time input - sec-%02d min-%02d hour-%02d mday-%02d mon-%02d year-%02d wday-%02d epoch-%d rtc_epoch-%d\n",
248 tm->tm_sec,tm->tm_min,tm->tm_hour,tm->tm_mday,tm->tm_mon,tm->tm_year,tm->tm_wday, epoch, rtc_epoch));
249 x1205_debug((KERN_DEBUG "BCD write data - sec-%02x min-%02x hour-%02x mday-%02x mon-%02x year-%02x wday-%02x y2k-%02x\n",
250 buf[2],buf[3],buf[4],buf[5],buf[6], buf[7], buf[8], buf[9]));
252 if ((i2c_transfer(client->adapter, msgs, 4)) != 4)
256 #else //do this if page writes aren't working
259 static unsigned char data[3] = { 0,};
260 static unsigned char buf[8];
262 buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
263 buf[CCR_MIN] = BIN2BCD(tm->tm_min);
264 buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_MILBIT; // set 24 hour format
267 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
268 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon); // input is 0-11
269 buf[CCR_YEAR] = BIN2BCD((tm->tm_year + epoch - rtc_epoch)); // input is yrs since 1900
270 buf[CCR_WDAY] = tm->tm_wday & 7;
271 buf[CCR_Y2K] = BIN2BCD((rtc_epoch/100));
274 x1205_debug((KERN_DEBUG "rtc_time input - sec-%02d min-%02d hour-%02d mday-%02d mon-%02d year-%02d wday-%02d epoch-%d rtc_epoch-%d\n",
275 tm->tm_sec,tm->tm_min,tm->tm_hour,tm->tm_mday,tm->tm_mon,tm->tm_year,tm->tm_wday, epoch, rtc_epoch));
277 xfer = i2c_master_send(client, wel, 3);
278 x1205_debug((KERN_DEBUG "wen - %x\n", xfer));
282 xfer = i2c_master_send(client, rwel, 3);
283 x1205_debug((KERN_DEBUG "wenb - %x\n", xfer));
287 for (i = 0; i < count; i++) {
288 data[1] = i + reg_base;
290 xfer = i2c_master_send(client, data, 3);
291 x1205_debug((KERN_DEBUG "xfer - %d addr - %02x data - %02x\n", xfer, data[1], data[2]));
296 xfer = i2c_master_send(client, diswe, 3);
297 x1205_debug((KERN_DEBUG "wdis - %x\n", xfer));
303 //=============================================================================
305 static int x1205_attach(struct i2c_adapter *adapter)
311 x1205_i2c_client.adapter = adapter;
312 x1205_i2c_client.id++;
314 if ((x1205_get_datetime(&x1205_i2c_client, &tm, X1205_CCR_BASE)) != NOERR) //test for functional driver
317 if ((errno = i2c_attach_client(&x1205_i2c_client)) != NOERR)
320 /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary whether
321 * it stores the most close value or the value with partial seconds
322 * truncated, however it is important for x1205_sync_rtc that it be
323 * defined to store the truncated value. This is because otherwise it
324 * is necessary to read both xtime.tv_sec and xtime.tv_nsec in the
325 * sync function, and atomic reads of >32bits on ARM are not possible.
326 * So storing the most close value would slow down the sync API. So
327 * Here we have the truncated value and the best guess is to add 0.5s
329 tv.tv_nsec = NSEC_PER_SEC >> 1;
330 /* WARNING: this is not the C library 'mktime' call, it is a built in
331 * inline function from include/linux/time.h. It expects (requires)
332 * the month to be in the range 1-12
334 tv.tv_sec = mktime(tm.tm_year+epoch, tm.tm_mon+1, tm.tm_mday, tm.tm_hour,
335 tm.tm_min, tm.tm_sec);
336 do_settimeofday(&tv);
337 set_rtc = x1205_sync_rtc;
339 printk(KERN_DEBUG "%s attached on adapter %s\n",x1205_i2c_client.name,
340 x1205_i2c_client.adapter->name); //why is this name a null string?
345 static int x1205_detach(struct i2c_client *client)
349 if ((errno = i2c_detach_client(client)) != 0) {
350 printk(KERN_DEBUG "i2c_detach failed - errno = %d\n", errno);
357 // make sure the rtc_time values are in bounds
358 static int x1205_validate_tm(struct rtc_time *tm, int datetoo)
361 /* This used to be 1900, not epoch, but all the read APIs subtract
362 * epoch, not 1900, and the result of these APIs *is* fed back in
363 * to x1205_command (which calls this.)
365 tm->tm_year += epoch;
367 /* The RTC uses a byte containing a BCD year value, so this is
368 * limited to the range 0..99 from rtc_epoch.
370 if ((tm->tm_year < rtc_epoch || tm->tm_year > rtc_epoch + 99) ||
371 ((tm->tm_mon > 11) || tm->tm_mon < 0 || (tm->tm_mday <= 0)) ||
372 (tm->tm_mday > (days_in_mo[tm->tm_mon] + ( (tm->tm_mon == 1) &&
373 ((!(tm->tm_year % 4) && (tm->tm_year % 100) ) || !(tm->tm_year % 400)))))
375 printk(KERN_DEBUG "x1205_validate_tm: invalid date:\t%04d,%02d,%02d\n",
376 tm->tm_year, tm->tm_mon, tm->tm_mday);
380 tm->tm_year -= epoch;
383 if (((tm->tm_hour < 0) || (tm->tm_min < 0) || (tm->tm_sec < 0)) ||
384 ((tm->tm_hour >= 24) || (tm->tm_min >= 60) || (tm->tm_sec >= 60))) {
385 printk(KERN_DEBUG "x1205_validate_tm: invalid time:\t%02d,%02d,%02d\n",
386 tm->tm_hour, tm->tm_min, tm->tm_sec);
393 static int x1205_command(struct i2c_client *client, unsigned int cmd, void *tm)
395 int errno, dodate = RTC_DATETOO;
397 if (client == NULL || tm == NULL)
399 if (!capable(CAP_SYS_TIME))
402 x1205_debug((KERN_DEBUG "x1205_command %d\n", cmd));
405 case RTC_GETDATETIME:
406 return x1205_get_datetime(client, tm, X1205_CCR_BASE);
408 case RTC_SETTIME: // note fall thru
410 case RTC_SETDATETIME:
411 if ((errno = x1205_validate_tm(tm, dodate)) < NOERR)
413 return x1205_set_datetime(client, tm, dodate, X1205_CCR_BASE);
420 static int x1205_sync_rtc(void)
422 /* sync to xtime, tv_nsec is ignored (see the command above about
423 * use of the truncated value) so this is pretty easy. kas11's
424 * code took are to do RTC_SETTIME - i.e. not set the date. My
425 * assumption is that this may be because date setting is slow, so
426 * this feature is retained. NTP does a sync when the time is
427 * changed, including significant changes. The sync needs to
428 * set the date correctly if necessary.
431 time_t new_s, old_s, div, rem;
434 x1205_debug((KERN_DEBUG "x1205_sync_rtc entry\n"));
437 int err = x1205_command(&x1205_i2c_client, RTC_GETDATETIME, &tm);
439 printk(KERN_DEBUG "x1205_sync_rtc exit (failed to get date)\n");
444 old_s = mktime(tm.tm_year+epoch, tm.tm_mon+1, tm.tm_mday,
445 tm.tm_hour, tm.tm_min, tm.tm_sec);
446 new_s = xtime.tv_sec;
448 /* Optimisation, the clock only stores seconds so it's pointless
449 * to reset it if it is within 1s of now.
451 if (old_s - 1 <= new_s && new_s <= old_s + 1) {
452 x1205_debug((KERN_DEBUG "x1205_sync_rtc exit (RTC in sync)\n"));
457 tm.tm_sec = new_s - div*60;
460 tm.tm_min = rem - div*60;
463 tm.tm_hour = rem - div*24;
465 /* Now subtract the result from the original 'new' value. This
466 * should be zero, if not an mday change is required. Notice
467 * that this will tend to fire for small drifts close to UTC midnight.
470 rem = new_s - mktime(tm.tm_year+epoch, tm.tm_mon+1, tm.tm_mday,
471 tm.tm_hour, tm.tm_min, tm.tm_sec);
475 /* Make an approximation to year/month/day. */
477 div = (2*div)/61; // 30.5 days/month
478 tm.tm_mday = 1 + rem - (div*61)/2;
482 while (tm.tm_mday > days_in_mo[rem]) {
483 tm.tm_mday -= days_in_mo[rem];
490 div += 1970; // base of tv_sec
492 /* Calculate the error in the approximation as a signed
495 dif = new_s - mktime(div, tm.tm_mon+1, tm.tm_mday,
496 tm.tm_hour, tm.tm_min, tm.tm_sec);
501 while (dif >= 86400) {
506 printk(KERN_ERR "x1205_sync_rtc (error in date %d)\n", dif);
508 /* Normalise the result. */
509 while (tm.tm_mday <= 0) {
510 if (--(tm.tm_mon) < 0) {
514 tm.tm_mday += days_in_mo[tm.tm_mon] + (tm.tm_mon==1 &&
515 ((!(div % 4) && (div % 100) ) || !(div % 400)));
519 rem = days_in_mo[tm.tm_mon] + (tm.tm_mon==1 &&
520 ((!(div % 4) && (div % 100) ) || !(div % 400)));
521 if (tm.tm_mday > rem) {
523 if (++(tm.tm_mon) >= 12) {
532 tm.tm_year = div-epoch;
533 cmd = RTC_SETDATETIME;
534 printk(KERN_DEBUG "x1205_sync_rtc exit (change date %d)\n", new_s-old_s);
536 printk(KERN_DEBUG "x1205_sync_rtc exit (change seconds %d)\n", new_s-old_s);
537 /* But avoid the race condition when the date is about to
540 if (tm.tm_min == 59 && tm.tm_hour == 23)
541 cmd = RTC_SETDATETIME;
544 return x1205_command(&x1205_i2c_client, cmd, &tm);
547 static int x1205_read(struct file *file, char *buf, size_t count, loff_t *ptr)
551 if ((x1205_get_datetime(&x1205_i2c_client, &tm, X1205_CCR_BASE)) < NOERR)
553 return copy_to_user(buf, &tm, sizeof(tm)) ? -EFAULT : NOERR;
556 //==============================================================================
558 static int x1205_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
564 x1205_debug((KERN_DEBUG "ioctl = %x\n", cmd));
568 if ((x1205_get_datetime(&x1205_i2c_client, &tm, X1205_CCR_BASE)) < NOERR)
573 if (!capable(CAP_SYS_TIME))
576 if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
578 if ((errno = x1205_validate_tm(&tm, RTC_DATETOO)) < NOERR)
580 return x1205_set_datetime(&x1205_i2c_client, &tm, RTC_DATETOO, X1205_CCR_BASE);
582 case RTC_ALM_SET: //FIXME: set Control Regs
583 if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
585 return x1205_set_datetime(&x1205_i2c_client, &tm, RTC_DATETOO, X1205_ALM0_BASE);
588 if ((x1205_get_datetime(&x1205_i2c_client, &tm, X1205_ALM0_BASE)) < NOERR)
594 return put_user (epoch, (unsigned long __user *)arg);
600 if (!capable(CAP_SYS_TIME))
609 return copy_to_user((void __user *)arg, &tm, sizeof tm) ? -EFAULT : 0;
613 static int x1205_read_proc(char *buf, char **start, off_t off, int len, int *eof, void *data)
618 if ((errno = x1205_get_datetime(&x1205_i2c_client, &tm, X1205_CCR_BASE)) < NOERR)
621 // here we return the real year and the month as 1-12 since it is human-readable
622 slen = sprintf(buf, "rtc_time\t: %02d:%02d:%02d\nrtc_date\t: %04d-%02d-%02d\n",
623 tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_year + 1900, tm.tm_mon+1, tm.tm_mday);
624 x1205_debug((KERN_DEBUG "raw rtc_time\t: %02d:%02d:%02d\nraw rtc_date\t: %04d-%02d-%02d\n",
625 tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_year, tm.tm_mon, tm.tm_mday));
627 if (slen <= off + len)
639 static int __init x1205_init(void)
643 printk(KERN_INFO "LOADED %s\n", DRIVERNAME);
645 if ((errno = i2c_add_driver(&x1205_driver)) != NOERR) {
646 dev_dbg(x1205_i2c_client.dev, "x1205_init failed - errno = %d\n", errno);
649 if ((errno = misc_register(&x1205_miscdev)) != NOERR) {
650 dev_dbg(x1205_i2c_client.dev, "Register Misc Driver failed - errno = %d\n", errno);
651 i2c_del_driver(&x1205_driver);
654 if (create_proc_read_entry("driver/rtc", 0, NULL, x1205_read_proc, NULL) < NOERR)
656 if ((x1205_get_datetime(&x1205_i2c_client, &tm, X1205_CCR_BASE)) != NOERR) //test for functionality
662 static void __exit x1205_exit(void)
664 remove_proc_entry("driver/rtc", NULL);
665 misc_deregister(&x1205_miscdev);
666 i2c_del_driver(&x1205_driver);
670 MODULE_AUTHOR("Karen Spearel <kas11@tampabay.rr.com>");
671 MODULE_DESCRIPTION("Xicor X1205-RTC Driver");
672 MODULE_LICENSE("GPL");
673 static int debug = 7;
674 module_param(debug, bool, 0644);
675 MODULE_PARM_DESC(debug, "Debugging enabled = 1");
677 module_init(x1205_init);
678 module_exit(x1205_exit);