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1abb0dc9 DB |
1 | /* |
2 | * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips. | |
3 | * | |
4 | * Copyright (C) 2005 James Chapman (ds1337 core) | |
5 | * Copyright (C) 2006 David Brownell | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/i2c.h> | |
16 | #include <linux/string.h> | |
17 | #include <linux/rtc.h> | |
18 | #include <linux/bcd.h> | |
19 | ||
20 | ||
21 | ||
22 | /* We can't determine type by probing, but if we expect pre-Linux code | |
23 | * to have set the chip up as a clock (turning on the oscillator and | |
24 | * setting the date and time), Linux can ignore the non-clock features. | |
25 | * That's a natural job for a factory or repair bench. | |
26 | * | |
045e0e85 DB |
27 | * This is currently a simple no-alarms driver. If your board has the |
28 | * alarm irq wired up on a ds1337 or ds1339, and you want to use that, | |
29 | * then look at the rtc-rs5c372 driver for code to steal... | |
1abb0dc9 DB |
30 | */ |
31 | enum ds_type { | |
045e0e85 DB |
32 | ds_1307, |
33 | ds_1337, | |
34 | ds_1338, | |
35 | ds_1339, | |
36 | ds_1340, | |
37 | m41t00, | |
1abb0dc9 DB |
38 | // rs5c372 too? different address... |
39 | }; | |
40 | ||
1abb0dc9 DB |
41 | |
42 | /* RTC registers don't differ much, except for the century flag */ | |
43 | #define DS1307_REG_SECS 0x00 /* 00-59 */ | |
44 | # define DS1307_BIT_CH 0x80 | |
be5f59f4 | 45 | # define DS1340_BIT_nEOSC 0x80 |
1abb0dc9 DB |
46 | #define DS1307_REG_MIN 0x01 /* 00-59 */ |
47 | #define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */ | |
c065f35c DB |
48 | # define DS1307_BIT_12HR 0x40 /* in REG_HOUR */ |
49 | # define DS1307_BIT_PM 0x20 /* in REG_HOUR */ | |
1abb0dc9 DB |
50 | # define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */ |
51 | # define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */ | |
52 | #define DS1307_REG_WDAY 0x03 /* 01-07 */ | |
53 | #define DS1307_REG_MDAY 0x04 /* 01-31 */ | |
54 | #define DS1307_REG_MONTH 0x05 /* 01-12 */ | |
55 | # define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */ | |
56 | #define DS1307_REG_YEAR 0x06 /* 00-99 */ | |
57 | ||
58 | /* Other registers (control, status, alarms, trickle charge, NVRAM, etc) | |
045e0e85 DB |
59 | * start at 7, and they differ a LOT. Only control and status matter for |
60 | * basic RTC date and time functionality; be careful using them. | |
1abb0dc9 | 61 | */ |
045e0e85 | 62 | #define DS1307_REG_CONTROL 0x07 /* or ds1338 */ |
1abb0dc9 | 63 | # define DS1307_BIT_OUT 0x80 |
be5f59f4 | 64 | # define DS1338_BIT_OSF 0x20 |
1abb0dc9 DB |
65 | # define DS1307_BIT_SQWE 0x10 |
66 | # define DS1307_BIT_RS1 0x02 | |
67 | # define DS1307_BIT_RS0 0x01 | |
68 | #define DS1337_REG_CONTROL 0x0e | |
69 | # define DS1337_BIT_nEOSC 0x80 | |
70 | # define DS1337_BIT_RS2 0x10 | |
71 | # define DS1337_BIT_RS1 0x08 | |
72 | # define DS1337_BIT_INTCN 0x04 | |
73 | # define DS1337_BIT_A2IE 0x02 | |
74 | # define DS1337_BIT_A1IE 0x01 | |
045e0e85 DB |
75 | #define DS1340_REG_CONTROL 0x07 |
76 | # define DS1340_BIT_OUT 0x80 | |
77 | # define DS1340_BIT_FT 0x40 | |
78 | # define DS1340_BIT_CALIB_SIGN 0x20 | |
79 | # define DS1340_M_CALIBRATION 0x1f | |
be5f59f4 RG |
80 | #define DS1340_REG_FLAG 0x09 |
81 | # define DS1340_BIT_OSF 0x80 | |
1abb0dc9 DB |
82 | #define DS1337_REG_STATUS 0x0f |
83 | # define DS1337_BIT_OSF 0x80 | |
84 | # define DS1337_BIT_A2I 0x02 | |
85 | # define DS1337_BIT_A1I 0x01 | |
86 | #define DS1339_REG_TRICKLE 0x10 | |
87 | ||
88 | ||
89 | ||
90 | struct ds1307 { | |
91 | u8 reg_addr; | |
92 | u8 regs[8]; | |
93 | enum ds_type type; | |
94 | struct i2c_msg msg[2]; | |
045e0e85 DB |
95 | struct i2c_client *client; |
96 | struct i2c_client dev; | |
1abb0dc9 DB |
97 | struct rtc_device *rtc; |
98 | }; | |
99 | ||
045e0e85 DB |
100 | struct chip_desc { |
101 | char name[9]; | |
102 | unsigned nvram56:1; | |
103 | unsigned alarm:1; | |
104 | enum ds_type type; | |
105 | }; | |
106 | ||
107 | static const struct chip_desc chips[] = { { | |
108 | .name = "ds1307", | |
109 | .type = ds_1307, | |
110 | .nvram56 = 1, | |
111 | }, { | |
112 | .name = "ds1337", | |
113 | .type = ds_1337, | |
114 | .alarm = 1, | |
115 | }, { | |
116 | .name = "ds1338", | |
117 | .type = ds_1338, | |
118 | .nvram56 = 1, | |
119 | }, { | |
120 | .name = "ds1339", | |
121 | .type = ds_1339, | |
122 | .alarm = 1, | |
123 | }, { | |
124 | .name = "ds1340", | |
125 | .type = ds_1340, | |
126 | }, { | |
127 | .name = "m41t00", | |
128 | .type = m41t00, | |
129 | }, }; | |
130 | ||
131 | static inline const struct chip_desc *find_chip(const char *s) | |
132 | { | |
133 | unsigned i; | |
134 | ||
135 | for (i = 0; i < ARRAY_SIZE(chips); i++) | |
136 | if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0) | |
137 | return &chips[i]; | |
138 | return NULL; | |
139 | } | |
1abb0dc9 DB |
140 | |
141 | static int ds1307_get_time(struct device *dev, struct rtc_time *t) | |
142 | { | |
143 | struct ds1307 *ds1307 = dev_get_drvdata(dev); | |
144 | int tmp; | |
145 | ||
045e0e85 | 146 | /* read the RTC date and time registers all at once */ |
1abb0dc9 DB |
147 | ds1307->msg[1].flags = I2C_M_RD; |
148 | ds1307->msg[1].len = 7; | |
149 | ||
045e0e85 DB |
150 | tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent), |
151 | ds1307->msg, 2); | |
1abb0dc9 DB |
152 | if (tmp != 2) { |
153 | dev_err(dev, "%s error %d\n", "read", tmp); | |
154 | return -EIO; | |
155 | } | |
156 | ||
157 | dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", | |
158 | "read", | |
159 | ds1307->regs[0], ds1307->regs[1], | |
160 | ds1307->regs[2], ds1307->regs[3], | |
161 | ds1307->regs[4], ds1307->regs[5], | |
162 | ds1307->regs[6]); | |
163 | ||
164 | t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f); | |
165 | t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f); | |
166 | tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f; | |
167 | t->tm_hour = BCD2BIN(tmp); | |
168 | t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1; | |
169 | t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f); | |
170 | tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f; | |
171 | t->tm_mon = BCD2BIN(tmp) - 1; | |
172 | ||
173 | /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */ | |
174 | t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100; | |
175 | ||
176 | dev_dbg(dev, "%s secs=%d, mins=%d, " | |
177 | "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", | |
178 | "read", t->tm_sec, t->tm_min, | |
179 | t->tm_hour, t->tm_mday, | |
180 | t->tm_mon, t->tm_year, t->tm_wday); | |
181 | ||
045e0e85 DB |
182 | /* initial clock setting can be undefined */ |
183 | return rtc_valid_tm(t); | |
1abb0dc9 DB |
184 | } |
185 | ||
186 | static int ds1307_set_time(struct device *dev, struct rtc_time *t) | |
187 | { | |
188 | struct ds1307 *ds1307 = dev_get_drvdata(dev); | |
189 | int result; | |
190 | int tmp; | |
191 | u8 *buf = ds1307->regs; | |
192 | ||
193 | dev_dbg(dev, "%s secs=%d, mins=%d, " | |
194 | "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", | |
11966adc JG |
195 | "write", t->tm_sec, t->tm_min, |
196 | t->tm_hour, t->tm_mday, | |
197 | t->tm_mon, t->tm_year, t->tm_wday); | |
1abb0dc9 DB |
198 | |
199 | *buf++ = 0; /* first register addr */ | |
200 | buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec); | |
201 | buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min); | |
202 | buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour); | |
203 | buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1); | |
204 | buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday); | |
205 | buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1); | |
206 | ||
207 | /* assume 20YY not 19YY */ | |
208 | tmp = t->tm_year - 100; | |
209 | buf[DS1307_REG_YEAR] = BIN2BCD(tmp); | |
210 | ||
be5f59f4 RG |
211 | switch (ds1307->type) { |
212 | case ds_1337: | |
213 | case ds_1339: | |
1abb0dc9 | 214 | buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY; |
be5f59f4 RG |
215 | break; |
216 | case ds_1340: | |
1abb0dc9 DB |
217 | buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN |
218 | | DS1340_BIT_CENTURY; | |
be5f59f4 RG |
219 | break; |
220 | default: | |
221 | break; | |
222 | } | |
1abb0dc9 DB |
223 | |
224 | ds1307->msg[1].flags = 0; | |
225 | ds1307->msg[1].len = 8; | |
226 | ||
227 | dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", | |
228 | "write", buf[0], buf[1], buf[2], buf[3], | |
229 | buf[4], buf[5], buf[6]); | |
230 | ||
045e0e85 DB |
231 | result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent), |
232 | &ds1307->msg[1], 1); | |
1abb0dc9 DB |
233 | if (result != 1) { |
234 | dev_err(dev, "%s error %d\n", "write", tmp); | |
235 | return -EIO; | |
236 | } | |
237 | return 0; | |
238 | } | |
239 | ||
ff8371ac | 240 | static const struct rtc_class_ops ds13xx_rtc_ops = { |
1abb0dc9 DB |
241 | .read_time = ds1307_get_time, |
242 | .set_time = ds1307_set_time, | |
243 | }; | |
244 | ||
245 | static struct i2c_driver ds1307_driver; | |
246 | ||
c065f35c | 247 | static int __devinit ds1307_probe(struct i2c_client *client) |
1abb0dc9 DB |
248 | { |
249 | struct ds1307 *ds1307; | |
250 | int err = -ENODEV; | |
1abb0dc9 | 251 | int tmp; |
045e0e85 | 252 | const struct chip_desc *chip; |
c065f35c | 253 | struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); |
1abb0dc9 | 254 | |
c065f35c DB |
255 | chip = find_chip(client->name); |
256 | if (!chip) { | |
257 | dev_err(&client->dev, "unknown chip type '%s'\n", | |
258 | client->name); | |
259 | return -ENODEV; | |
1abb0dc9 DB |
260 | } |
261 | ||
c065f35c DB |
262 | if (!i2c_check_functionality(adapter, |
263 | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) | |
264 | return -EIO; | |
265 | ||
266 | if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) | |
267 | return -ENOMEM; | |
045e0e85 DB |
268 | |
269 | ds1307->client = client; | |
1abb0dc9 DB |
270 | i2c_set_clientdata(client, ds1307); |
271 | ||
272 | ds1307->msg[0].addr = client->addr; | |
273 | ds1307->msg[0].flags = 0; | |
274 | ds1307->msg[0].len = 1; | |
275 | ds1307->msg[0].buf = &ds1307->reg_addr; | |
276 | ||
277 | ds1307->msg[1].addr = client->addr; | |
278 | ds1307->msg[1].flags = I2C_M_RD; | |
279 | ds1307->msg[1].len = sizeof(ds1307->regs); | |
280 | ds1307->msg[1].buf = ds1307->regs; | |
281 | ||
045e0e85 DB |
282 | ds1307->type = chip->type; |
283 | ||
284 | switch (ds1307->type) { | |
285 | case ds_1337: | |
286 | case ds_1339: | |
1abb0dc9 DB |
287 | ds1307->reg_addr = DS1337_REG_CONTROL; |
288 | ds1307->msg[1].len = 2; | |
289 | ||
be5f59f4 | 290 | /* get registers that the "rtc" read below won't read... */ |
045e0e85 | 291 | tmp = i2c_transfer(adapter, ds1307->msg, 2); |
1abb0dc9 DB |
292 | if (tmp != 2) { |
293 | pr_debug("read error %d\n", tmp); | |
294 | err = -EIO; | |
295 | goto exit_free; | |
296 | } | |
297 | ||
298 | ds1307->reg_addr = 0; | |
299 | ds1307->msg[1].len = sizeof(ds1307->regs); | |
300 | ||
be5f59f4 RG |
301 | /* oscillator off? turn it on, so clock can tick. */ |
302 | if (ds1307->regs[0] & DS1337_BIT_nEOSC) | |
303 | i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, | |
304 | ds1307->regs[0] & ~DS1337_BIT_nEOSC); | |
305 | ||
306 | /* oscillator fault? clear flag, and warn */ | |
307 | if (ds1307->regs[1] & DS1337_BIT_OSF) { | |
308 | i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, | |
309 | ds1307->regs[1] & ~DS1337_BIT_OSF); | |
310 | dev_warn(&client->dev, "SET TIME!\n"); | |
1abb0dc9 | 311 | } |
045e0e85 DB |
312 | break; |
313 | default: | |
314 | break; | |
315 | } | |
1abb0dc9 DB |
316 | |
317 | read_rtc: | |
318 | /* read RTC registers */ | |
319 | ||
045e0e85 | 320 | tmp = i2c_transfer(adapter, ds1307->msg, 2); |
1abb0dc9 DB |
321 | if (tmp != 2) { |
322 | pr_debug("read error %d\n", tmp); | |
323 | err = -EIO; | |
324 | goto exit_free; | |
325 | } | |
326 | ||
327 | /* minimal sanity checking; some chips (like DS1340) don't | |
328 | * specify the extra bits as must-be-zero, but there are | |
329 | * still a few values that are clearly out-of-range. | |
330 | */ | |
331 | tmp = ds1307->regs[DS1307_REG_SECS]; | |
045e0e85 | 332 | switch (ds1307->type) { |
be5f59f4 RG |
333 | case ds_1340: |
334 | /* FIXME read register with DS1340_BIT_OSF, use that to | |
335 | * trigger the "set time" warning (*after* restarting the | |
336 | * oscillator!) instead of this weaker ds1307/m41t00 test. | |
337 | */ | |
045e0e85 | 338 | case ds_1307: |
045e0e85 | 339 | case m41t00: |
be5f59f4 | 340 | /* clock halted? turn it on, so clock can tick. */ |
045e0e85 | 341 | if (tmp & DS1307_BIT_CH) { |
be5f59f4 RG |
342 | i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0); |
343 | dev_warn(&client->dev, "SET TIME!\n"); | |
045e0e85 | 344 | goto read_rtc; |
1abb0dc9 | 345 | } |
045e0e85 | 346 | break; |
be5f59f4 RG |
347 | case ds_1338: |
348 | /* clock halted? turn it on, so clock can tick. */ | |
045e0e85 | 349 | if (tmp & DS1307_BIT_CH) |
be5f59f4 RG |
350 | i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0); |
351 | ||
352 | /* oscillator fault? clear flag, and warn */ | |
353 | if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) { | |
354 | i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL, | |
bd16f9eb | 355 | ds1307->regs[DS1307_REG_CONTROL] |
be5f59f4 RG |
356 | & ~DS1338_BIT_OSF); |
357 | dev_warn(&client->dev, "SET TIME!\n"); | |
358 | goto read_rtc; | |
359 | } | |
045e0e85 | 360 | break; |
c065f35c DB |
361 | case ds_1337: |
362 | case ds_1339: | |
045e0e85 | 363 | break; |
1abb0dc9 | 364 | } |
045e0e85 DB |
365 | |
366 | tmp = ds1307->regs[DS1307_REG_SECS]; | |
1abb0dc9 DB |
367 | tmp = BCD2BIN(tmp & 0x7f); |
368 | if (tmp > 60) | |
c065f35c | 369 | goto exit_bad; |
1abb0dc9 DB |
370 | tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f); |
371 | if (tmp > 60) | |
c065f35c | 372 | goto exit_bad; |
1abb0dc9 DB |
373 | |
374 | tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f); | |
375 | if (tmp == 0 || tmp > 31) | |
c065f35c | 376 | goto exit_bad; |
1abb0dc9 DB |
377 | |
378 | tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f); | |
379 | if (tmp == 0 || tmp > 12) | |
c065f35c | 380 | goto exit_bad; |
1abb0dc9 | 381 | |
1abb0dc9 | 382 | tmp = ds1307->regs[DS1307_REG_HOUR]; |
c065f35c DB |
383 | switch (ds1307->type) { |
384 | case ds_1340: | |
385 | case m41t00: | |
386 | /* NOTE: ignores century bits; fix before deploying | |
387 | * systems that will run through year 2100. | |
388 | */ | |
389 | break; | |
390 | default: | |
391 | if (!(tmp & DS1307_BIT_12HR)) | |
392 | break; | |
393 | ||
394 | /* Be sure we're in 24 hour mode. Multi-master systems | |
395 | * take note... | |
396 | */ | |
397 | tmp = BCD2BIN(tmp & 0x1f); | |
398 | if (tmp == 12) | |
399 | tmp = 0; | |
400 | if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM) | |
401 | tmp += 12; | |
1abb0dc9 DB |
402 | i2c_smbus_write_byte_data(client, |
403 | DS1307_REG_HOUR, | |
404 | BIN2BCD(tmp)); | |
405 | } | |
406 | ||
1abb0dc9 DB |
407 | ds1307->rtc = rtc_device_register(client->name, &client->dev, |
408 | &ds13xx_rtc_ops, THIS_MODULE); | |
409 | if (IS_ERR(ds1307->rtc)) { | |
410 | err = PTR_ERR(ds1307->rtc); | |
411 | dev_err(&client->dev, | |
412 | "unable to register the class device\n"); | |
c065f35c | 413 | goto exit_free; |
1abb0dc9 DB |
414 | } |
415 | ||
416 | return 0; | |
417 | ||
c065f35c DB |
418 | exit_bad: |
419 | dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", | |
420 | "bogus register", | |
421 | ds1307->regs[0], ds1307->regs[1], | |
422 | ds1307->regs[2], ds1307->regs[3], | |
423 | ds1307->regs[4], ds1307->regs[5], | |
424 | ds1307->regs[6]); | |
425 | ||
1abb0dc9 DB |
426 | exit_free: |
427 | kfree(ds1307); | |
1abb0dc9 DB |
428 | return err; |
429 | } | |
430 | ||
c065f35c | 431 | static int __devexit ds1307_remove(struct i2c_client *client) |
1abb0dc9 | 432 | { |
1abb0dc9 DB |
433 | struct ds1307 *ds1307 = i2c_get_clientdata(client); |
434 | ||
435 | rtc_device_unregister(ds1307->rtc); | |
1abb0dc9 DB |
436 | kfree(ds1307); |
437 | return 0; | |
438 | } | |
439 | ||
440 | static struct i2c_driver ds1307_driver = { | |
441 | .driver = { | |
c065f35c | 442 | .name = "rtc-ds1307", |
1abb0dc9 DB |
443 | .owner = THIS_MODULE, |
444 | }, | |
c065f35c DB |
445 | .probe = ds1307_probe, |
446 | .remove = __devexit_p(ds1307_remove), | |
1abb0dc9 DB |
447 | }; |
448 | ||
449 | static int __init ds1307_init(void) | |
450 | { | |
451 | return i2c_add_driver(&ds1307_driver); | |
452 | } | |
453 | module_init(ds1307_init); | |
454 | ||
455 | static void __exit ds1307_exit(void) | |
456 | { | |
457 | i2c_del_driver(&ds1307_driver); | |
458 | } | |
459 | module_exit(ds1307_exit); | |
460 | ||
461 | MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips"); | |
462 | MODULE_LICENSE("GPL"); |