2 * x1205.c - An i2c driver for the Xicor X1205 RTC
3 * Copyright 2004 Karen Spearel
4 * Copyright 2005 Alessandro Zummo
6 * please send all reports to:
7 * kas11 at tampabay dot rr dot com
8 * a dot zummo at towertech dot it
10 * based on the other drivers in this same directory.
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/slab.h>
21 #include <linux/i2c.h>
22 #include <linux/string.h>
23 #include <linux/bcd.h>
24 #include <linux/rtc.h>
25 #include <linux/list.h>
27 #include <linux/x1205.h>
29 #define DRV_VERSION "0.9.9"
31 /* Addresses to scan: none. This chip is located at
32 * 0x6f and uses a two bytes register addressing.
33 * Two bytes need to be written to read a single register,
34 * while most other chips just require one and take the second
35 * one as the data to be written. To prevent corrupting
36 * unknown chips, the user must explicitely set the probe parameter.
39 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
41 /* Insmod parameters */
43 I2C_CLIENT_MODULE_PARM(hctosys,
44 "Set the system time from the hardware clock upon initialization");
46 /* offsets into CCR area */
57 #define X1205_REG_SR 0x3F /* status register */
58 #define X1205_REG_Y2K 0x37
59 #define X1205_REG_DW 0x36
60 #define X1205_REG_YR 0x35
61 #define X1205_REG_MO 0x34
62 #define X1205_REG_DT 0x33
63 #define X1205_REG_HR 0x32
64 #define X1205_REG_MN 0x31
65 #define X1205_REG_SC 0x30
66 #define X1205_REG_DTR 0x13
67 #define X1205_REG_ATR 0x12
68 #define X1205_REG_INT 0x11
69 #define X1205_REG_0 0x10
70 #define X1205_REG_Y2K1 0x0F
71 #define X1205_REG_DWA1 0x0E
72 #define X1205_REG_YRA1 0x0D
73 #define X1205_REG_MOA1 0x0C
74 #define X1205_REG_DTA1 0x0B
75 #define X1205_REG_HRA1 0x0A
76 #define X1205_REG_MNA1 0x09
77 #define X1205_REG_SCA1 0x08
78 #define X1205_REG_Y2K0 0x07
79 #define X1205_REG_DWA0 0x06
80 #define X1205_REG_YRA0 0x05
81 #define X1205_REG_MOA0 0x04
82 #define X1205_REG_DTA0 0x03
83 #define X1205_REG_HRA0 0x02
84 #define X1205_REG_MNA0 0x01
85 #define X1205_REG_SCA0 0x00
87 #define X1205_CCR_BASE 0x30 /* Base address of CCR */
88 #define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */
90 #define X1205_SR_RTCF 0x01 /* Clock failure */
91 #define X1205_SR_WEL 0x02 /* Write Enable Latch */
92 #define X1205_SR_RWEL 0x04 /* Register Write Enable */
94 #define X1205_DTR_DTR0 0x01
95 #define X1205_DTR_DTR1 0x02
96 #define X1205_DTR_DTR2 0x04
98 #define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */
101 static int x1205_attach(struct i2c_adapter *adapter);
102 static int x1205_detach(struct i2c_client *client);
103 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
104 static int x1205_command(struct i2c_client *client, unsigned int cmd,
107 static struct i2c_driver x1205_driver = {
108 .owner = THIS_MODULE,
110 .flags = I2C_DF_NOTIFY,
111 .attach_adapter = &x1205_attach,
112 .detach_client = &x1205_detach,
116 struct i2c_client client;
117 struct list_head list;
121 static const unsigned char days_in_mo[] =
122 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
124 static LIST_HEAD(x1205_clients);
126 /* Workaround until the I2C subsytem will allow to send
127 * commands to a specific client. This function will send the command
128 * to the first client.
130 int x1205_do_command(unsigned int cmd, void *arg)
132 struct list_head *walk;
133 struct list_head *tmp;
134 struct x1205_data *data;
136 list_for_each_safe(walk, tmp, &x1205_clients) {
137 data = list_entry(walk, struct x1205_data, list);
138 return x1205_command(&data->client, cmd, arg);
144 #define is_leap(year) \
145 ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
147 /* make sure the rtc_time values are in bounds */
148 static int x1205_validate_tm(struct rtc_time *tm)
150 int year = tm->tm_year + 1900;
152 if ((tm->tm_year < 70) || (tm->tm_year > 255))
155 if ((tm->tm_mon > 11) || (tm->tm_mday == 0))
158 if (tm->tm_mday > days_in_mo[tm->tm_mon]
159 + ((tm->tm_mon == 1) && is_leap(year)))
162 if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) || (tm->tm_sec >= 60))
169 * In the routines that deal directly with the x1205 hardware, we use
170 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
171 * Epoch is initialized as 2000. Time is set to UTC.
173 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
176 unsigned char dt_addr[2] = { 0, reg_base };
177 static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
179 unsigned char buf[8], sr;
181 struct i2c_msg msgs[] = {
182 { client->addr, 0, 2, sr_addr }, /* setup read ptr */
183 { client->addr, I2C_M_RD, 1, &sr }, /* read status */
184 { client->addr, 0, 2, dt_addr }, /* setup read ptr */
185 { client->addr, I2C_M_RD, 8, buf }, /* read date */
188 struct x1205_data *data = i2c_get_clientdata(client);
190 /* read status register */
191 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
192 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
196 /* check for battery failure */
197 if (sr & X1205_SR_RTCF) {
198 dev_warn(&client->dev,
199 "Clock had a power failure, you must set the date.\n");
203 /* read date registers */
204 if ((i2c_transfer(client->adapter, &msgs[2], 2)) != 2) {
205 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
209 dev_dbg(&client->dev,
210 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
211 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
213 buf[0], buf[1], buf[2], buf[3],
214 buf[4], buf[5], buf[6], buf[7]);
216 tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
217 tm->tm_min = BCD2BIN(buf[CCR_MIN]);
218 tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
219 tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
220 tm->tm_mon = BCD2BIN(buf[CCR_MONTH]);
221 data->epoch = BCD2BIN(buf[CCR_Y2K]) * 100;
222 tm->tm_year = BCD2BIN(buf[CCR_YEAR]) + data->epoch - 1900;
223 tm->tm_wday = buf[CCR_WDAY];
225 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
226 "mday=%d, mon=%d, year=%d, wday=%d\n",
228 tm->tm_sec, tm->tm_min, tm->tm_hour,
229 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
234 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
235 int datetoo, u8 reg_base)
239 unsigned char buf[8];
241 static const unsigned char wel[3] = { 0, X1205_REG_SR,
244 static const unsigned char rwel[3] = { 0, X1205_REG_SR,
245 X1205_SR_WEL | X1205_SR_RWEL };
247 static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
249 struct x1205_data *data = i2c_get_clientdata(client);
251 /* check if all values in the tm struct are correct */
252 if ((err = x1205_validate_tm(tm)) < 0)
255 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
256 "mday=%d, mon=%d, year=%d, wday=%d\n",
258 tm->tm_sec, tm->tm_min, tm->tm_hour,
259 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
261 buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
262 buf[CCR_MIN] = BIN2BCD(tm->tm_min);
264 /* set hour and 24hr bit */
265 buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
267 /* should we also set the date? */
269 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
272 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon);
274 /* year, since 1900 */
275 buf[CCR_YEAR] = BIN2BCD(tm->tm_year + 1900 - data->epoch);
276 buf[CCR_WDAY] = tm->tm_wday & 0x07;
277 buf[CCR_Y2K] = BIN2BCD(data->epoch / 100);
280 /* this sequence is required to unlock the chip */
281 xfer = i2c_master_send(client, wel, 3);
283 dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);
287 xfer = i2c_master_send(client, rwel, 3);
289 dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);
293 /* write register's data */
294 for (i = 0; i < (datetoo ? 8 : 3); i++) {
295 unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
297 xfer = i2c_master_send(client, rdata, 3);
299 dev_err(&client->dev,
300 "%s: xfer=%d addr=%02x, data=%02x\n",
302 xfer, rdata[1], rdata[2]);
307 /* disable further writes */
308 xfer = i2c_master_send(client, diswe, 3);
310 dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);
317 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
320 static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
322 struct i2c_msg msgs[] = {
323 { client->addr, 0, 2, dtr_addr }, /* setup read ptr */
324 { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */
327 /* read dtr register */
328 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
329 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
333 dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);
337 if (dtr & X1205_DTR_DTR0)
340 if (dtr & X1205_DTR_DTR1)
343 if (dtr & X1205_DTR_DTR2)
349 static int x1205_get_atrim(struct i2c_client *client, int *trim)
352 static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
354 struct i2c_msg msgs[] = {
355 { client->addr, 0, 2, atr_addr }, /* setup read ptr */
356 { client->addr, I2C_M_RD, 1, &atr }, /* read atr */
359 /* read atr register */
360 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
361 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
365 dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);
367 /* atr is a two's complement value on 6 bits,
368 * perform sign extension. The formula is
369 * Catr = (atr * 0.25pF) + 11.00pF.
374 dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);
376 *trim = (atr * 250) + 11000;
378 dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);
383 static int x1205_hctosys(struct i2c_client *client)
390 err = x1205_command(client, X1205_CMD_GETDATETIME, &tm);
393 dev_err(&client->dev,
394 "Unable to set the system clock\n");
398 /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
399 * whether it stores the most close value or the value with partial
400 * seconds truncated. However, it is important that we use it to store
401 * the truncated value. This is because otherwise it is necessary,
402 * in an rtc sync function, to read both xtime.tv_sec and
403 * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
404 * of >32bits is not possible. So storing the most close value would
405 * slow down the sync API. So here we have the truncated value and
406 * the best guess is to add 0.5s.
409 tv.tv_nsec = NSEC_PER_SEC >> 1;
411 /* WARNING: this is not the C library 'mktime' call, it is a built in
412 * inline function from include/linux/time.h. It expects (requires)
413 * the month to be in the range 1-12
416 tv.tv_sec = mktime(tm.tm_year + 1900, tm.tm_mon + 1,
417 tm.tm_mday, tm.tm_hour,
418 tm.tm_min, tm.tm_sec);
420 do_settimeofday(&tv);
422 dev_info(&client->dev,
423 "setting the system clock to %d-%d-%d %d:%d:%d\n",
424 tm.tm_year + 1900, tm.tm_mon + 1,
425 tm.tm_mday, tm.tm_hour, tm.tm_min,
439 static int x1205_validate_client(struct i2c_client *client)
443 /* Probe array. We will read the register at the specified
444 * address and check if the given bits are zero.
446 static const unsigned char probe_zero_pattern[] = {
455 static const struct x1205_limit probe_limits_pattern[] = {
456 /* register, mask, min, max */
457 { X1205_REG_Y2K, 0xFF, 19, 20 },
458 { X1205_REG_DW, 0xFF, 0, 6 },
459 { X1205_REG_YR, 0xFF, 0, 99 },
460 { X1205_REG_MO, 0xFF, 0, 12 },
461 { X1205_REG_DT, 0xFF, 0, 31 },
462 { X1205_REG_HR, 0x7F, 0, 23 },
463 { X1205_REG_MN, 0xFF, 0, 59 },
464 { X1205_REG_SC, 0xFF, 0, 59 },
465 { X1205_REG_Y2K1, 0xFF, 19, 20 },
466 { X1205_REG_Y2K0, 0xFF, 19, 20 },
469 /* check that registers have bits a 0 where expected */
470 for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
473 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
475 struct i2c_msg msgs[2] = {
476 { client->addr, 0, 2, addr },
477 { client->addr, I2C_M_RD, 1, &buf },
480 xfer = i2c_transfer(client->adapter, msgs, 2);
482 dev_err(&client->adapter->dev,
483 "%s: could not read register %x\n",
484 __FUNCTION__, addr[1]);
489 if ((buf & probe_zero_pattern[i+1]) != 0) {
490 dev_err(&client->adapter->dev,
491 "%s: register=%02x, zero pattern=%d, value=%x\n",
492 __FUNCTION__, addr[1], i, buf);
498 /* check limits (only registers with bcd values) */
499 for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
500 unsigned char reg, value;
502 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
504 struct i2c_msg msgs[2] = {
505 { client->addr, 0, 2, addr },
506 { client->addr, I2C_M_RD, 1, ® },
509 xfer = i2c_transfer(client->adapter, msgs, 2);
512 dev_err(&client->adapter->dev,
513 "%s: could not read register %x\n",
514 __FUNCTION__, addr[1]);
519 value = BCD2BIN(reg & probe_limits_pattern[i].mask);
521 if (value > probe_limits_pattern[i].max ||
522 value < probe_limits_pattern[i].min) {
523 dev_dbg(&client->adapter->dev,
524 "%s: register=%x, lim pattern=%d, value=%d\n",
525 __FUNCTION__, addr[1], i, value);
534 static int x1205_attach(struct i2c_adapter *adapter)
536 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
538 return i2c_probe(adapter, &addr_data, x1205_probe);
541 int x1205_direct_attach(int adapter_id,
542 struct i2c_client_address_data *address_data)
545 struct i2c_adapter *adapter = i2c_get_adapter(adapter_id);
548 err = i2c_probe(adapter,
549 address_data, x1205_probe);
551 i2c_put_adapter(adapter);
559 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
561 struct i2c_client *client;
562 struct x1205_data *data;
566 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
568 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
573 if (!(data = kzalloc(sizeof(struct x1205_data), GFP_KERNEL))) {
578 /* Initialize our structures */
581 client = &data->client;
582 client->addr = address;
583 client->driver = &x1205_driver;
584 client->adapter = adapter;
586 strlcpy(client->name, "x1205", I2C_NAME_SIZE);
588 i2c_set_clientdata(client, data);
590 /* Verify the chip is really an X1205 */
592 if (x1205_validate_client(client) < 0) {
598 /* Inform the i2c layer */
599 if ((err = i2c_attach_client(client)))
602 list_add(&data->list, &x1205_clients);
604 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
606 /* If requested, set the system time */
608 x1205_hctosys(client);
619 static int x1205_detach(struct i2c_client *client)
622 struct x1205_data *data = i2c_get_clientdata(client);
624 dev_dbg(&client->dev, "%s\n", __FUNCTION__);
626 if ((err = i2c_detach_client(client)))
629 list_del(&data->list);
636 static int x1205_command(struct i2c_client *client, unsigned int cmd,
642 if (!capable(CAP_SYS_TIME))
645 dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
648 case X1205_CMD_GETDATETIME:
649 return x1205_get_datetime(client, param, X1205_CCR_BASE);
651 case X1205_CMD_SETTIME:
652 return x1205_set_datetime(client, param, 0,
655 case X1205_CMD_SETDATETIME:
656 return x1205_set_datetime(client, param, 1,
659 case X1205_CMD_GETALARM:
660 return x1205_get_datetime(client, param, X1205_ALM0_BASE);
662 case X1205_CMD_SETALARM:
663 return x1205_set_datetime(client, param, 1,
666 case X1205_CMD_GETDTRIM:
667 return x1205_get_dtrim(client, param);
669 case X1205_CMD_GETATRIM:
670 return x1205_get_atrim(client, param);
677 static int __init x1205_init(void)
679 return i2c_add_driver(&x1205_driver);
682 static void __exit x1205_exit(void)
684 i2c_del_driver(&x1205_driver);
688 "Karen Spearel <kas11@tampabay.rr.com>, "
689 "Alessandro Zummo <a.zummo@towertech.it>");
690 MODULE_DESCRIPTION("Xicor X1205 RTC driver");
691 MODULE_LICENSE("GPL");
692 MODULE_VERSION(DRV_VERSION);
694 EXPORT_SYMBOL_GPL(x1205_do_command);
695 EXPORT_SYMBOL_GPL(x1205_direct_attach);
697 module_init(x1205_init);
698 module_exit(x1205_exit);