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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 | * | |
27 | * If the I2C "force" mechanism is used, we assume the chip is a ds1337. | |
28 | * (Much better would be board-specific tables of I2C devices, along with | |
29 | * the platform_data drivers would use to sort such issues out.) | |
30 | */ | |
31 | enum ds_type { | |
32 | unknown = 0, | |
33 | ds_1307, /* or ds1338, ... */ | |
34 | ds_1337, /* or ds1339, ... */ | |
35 | ds_1340, /* or st m41t00, ... */ | |
36 | // rs5c372 too? different address... | |
37 | }; | |
38 | ||
39 | static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END }; | |
40 | ||
41 | I2C_CLIENT_INSMOD; | |
42 | ||
43 | ||
44 | ||
45 | /* RTC registers don't differ much, except for the century flag */ | |
46 | #define DS1307_REG_SECS 0x00 /* 00-59 */ | |
47 | # define DS1307_BIT_CH 0x80 | |
48 | #define DS1307_REG_MIN 0x01 /* 00-59 */ | |
49 | #define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */ | |
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) | |
59 | * start at 7, and they differ a lot. Only control and status matter for RTC; | |
60 | * be careful using them. | |
61 | */ | |
62 | #define DS1307_REG_CONTROL 0x07 | |
63 | # define DS1307_BIT_OUT 0x80 | |
64 | # define DS1307_BIT_SQWE 0x10 | |
65 | # define DS1307_BIT_RS1 0x02 | |
66 | # define DS1307_BIT_RS0 0x01 | |
67 | #define DS1337_REG_CONTROL 0x0e | |
68 | # define DS1337_BIT_nEOSC 0x80 | |
69 | # define DS1337_BIT_RS2 0x10 | |
70 | # define DS1337_BIT_RS1 0x08 | |
71 | # define DS1337_BIT_INTCN 0x04 | |
72 | # define DS1337_BIT_A2IE 0x02 | |
73 | # define DS1337_BIT_A1IE 0x01 | |
74 | #define DS1337_REG_STATUS 0x0f | |
75 | # define DS1337_BIT_OSF 0x80 | |
76 | # define DS1337_BIT_A2I 0x02 | |
77 | # define DS1337_BIT_A1I 0x01 | |
78 | #define DS1339_REG_TRICKLE 0x10 | |
79 | ||
80 | ||
81 | ||
82 | struct ds1307 { | |
83 | u8 reg_addr; | |
84 | u8 regs[8]; | |
85 | enum ds_type type; | |
86 | struct i2c_msg msg[2]; | |
87 | struct i2c_client client; | |
88 | struct rtc_device *rtc; | |
89 | }; | |
90 | ||
91 | ||
92 | static int ds1307_get_time(struct device *dev, struct rtc_time *t) | |
93 | { | |
94 | struct ds1307 *ds1307 = dev_get_drvdata(dev); | |
95 | int tmp; | |
96 | ||
97 | /* read the RTC registers all at once */ | |
98 | ds1307->msg[1].flags = I2C_M_RD; | |
99 | ds1307->msg[1].len = 7; | |
100 | ||
101 | tmp = i2c_transfer(ds1307->client.adapter, ds1307->msg, 2); | |
102 | if (tmp != 2) { | |
103 | dev_err(dev, "%s error %d\n", "read", tmp); | |
104 | return -EIO; | |
105 | } | |
106 | ||
107 | dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", | |
108 | "read", | |
109 | ds1307->regs[0], ds1307->regs[1], | |
110 | ds1307->regs[2], ds1307->regs[3], | |
111 | ds1307->regs[4], ds1307->regs[5], | |
112 | ds1307->regs[6]); | |
113 | ||
114 | t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f); | |
115 | t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f); | |
116 | tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f; | |
117 | t->tm_hour = BCD2BIN(tmp); | |
118 | t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1; | |
119 | t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f); | |
120 | tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f; | |
121 | t->tm_mon = BCD2BIN(tmp) - 1; | |
122 | ||
123 | /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */ | |
124 | t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100; | |
125 | ||
126 | dev_dbg(dev, "%s secs=%d, mins=%d, " | |
127 | "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", | |
128 | "read", t->tm_sec, t->tm_min, | |
129 | t->tm_hour, t->tm_mday, | |
130 | t->tm_mon, t->tm_year, t->tm_wday); | |
131 | ||
132 | return 0; | |
133 | } | |
134 | ||
135 | static int ds1307_set_time(struct device *dev, struct rtc_time *t) | |
136 | { | |
137 | struct ds1307 *ds1307 = dev_get_drvdata(dev); | |
138 | int result; | |
139 | int tmp; | |
140 | u8 *buf = ds1307->regs; | |
141 | ||
142 | dev_dbg(dev, "%s secs=%d, mins=%d, " | |
143 | "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", | |
11966adc JG |
144 | "write", t->tm_sec, t->tm_min, |
145 | t->tm_hour, t->tm_mday, | |
146 | t->tm_mon, t->tm_year, t->tm_wday); | |
1abb0dc9 DB |
147 | |
148 | *buf++ = 0; /* first register addr */ | |
149 | buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec); | |
150 | buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min); | |
151 | buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour); | |
152 | buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1); | |
153 | buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday); | |
154 | buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1); | |
155 | ||
156 | /* assume 20YY not 19YY */ | |
157 | tmp = t->tm_year - 100; | |
158 | buf[DS1307_REG_YEAR] = BIN2BCD(tmp); | |
159 | ||
160 | if (ds1307->type == ds_1337) | |
161 | buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY; | |
162 | else if (ds1307->type == ds_1340) | |
163 | buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN | |
164 | | DS1340_BIT_CENTURY; | |
165 | ||
166 | ds1307->msg[1].flags = 0; | |
167 | ds1307->msg[1].len = 8; | |
168 | ||
169 | dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", | |
170 | "write", buf[0], buf[1], buf[2], buf[3], | |
171 | buf[4], buf[5], buf[6]); | |
172 | ||
173 | result = i2c_transfer(ds1307->client.adapter, &ds1307->msg[1], 1); | |
174 | if (result != 1) { | |
175 | dev_err(dev, "%s error %d\n", "write", tmp); | |
176 | return -EIO; | |
177 | } | |
178 | return 0; | |
179 | } | |
180 | ||
ff8371ac | 181 | static const struct rtc_class_ops ds13xx_rtc_ops = { |
1abb0dc9 DB |
182 | .read_time = ds1307_get_time, |
183 | .set_time = ds1307_set_time, | |
184 | }; | |
185 | ||
186 | static struct i2c_driver ds1307_driver; | |
187 | ||
188 | static int __devinit | |
189 | ds1307_detect(struct i2c_adapter *adapter, int address, int kind) | |
190 | { | |
191 | struct ds1307 *ds1307; | |
192 | int err = -ENODEV; | |
193 | struct i2c_client *client; | |
194 | int tmp; | |
195 | ||
196 | if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) { | |
197 | err = -ENOMEM; | |
198 | goto exit; | |
199 | } | |
200 | ||
201 | client = &ds1307->client; | |
202 | client->addr = address; | |
203 | client->adapter = adapter; | |
204 | client->driver = &ds1307_driver; | |
205 | client->flags = 0; | |
206 | ||
207 | i2c_set_clientdata(client, ds1307); | |
208 | ||
209 | ds1307->msg[0].addr = client->addr; | |
210 | ds1307->msg[0].flags = 0; | |
211 | ds1307->msg[0].len = 1; | |
212 | ds1307->msg[0].buf = &ds1307->reg_addr; | |
213 | ||
214 | ds1307->msg[1].addr = client->addr; | |
215 | ds1307->msg[1].flags = I2C_M_RD; | |
216 | ds1307->msg[1].len = sizeof(ds1307->regs); | |
217 | ds1307->msg[1].buf = ds1307->regs; | |
218 | ||
219 | /* HACK: "force" implies "needs ds1337-style-oscillator setup" */ | |
220 | if (kind >= 0) { | |
221 | ds1307->type = ds_1337; | |
222 | ||
223 | ds1307->reg_addr = DS1337_REG_CONTROL; | |
224 | ds1307->msg[1].len = 2; | |
225 | ||
226 | tmp = i2c_transfer(client->adapter, ds1307->msg, 2); | |
227 | if (tmp != 2) { | |
228 | pr_debug("read error %d\n", tmp); | |
229 | err = -EIO; | |
230 | goto exit_free; | |
231 | } | |
232 | ||
233 | ds1307->reg_addr = 0; | |
234 | ds1307->msg[1].len = sizeof(ds1307->regs); | |
235 | ||
236 | /* oscillator is off; need to turn it on */ | |
237 | if ((ds1307->regs[0] & DS1337_BIT_nEOSC) | |
238 | || (ds1307->regs[1] & DS1337_BIT_OSF)) { | |
239 | printk(KERN_ERR "no ds1337 oscillator code\n"); | |
240 | goto exit_free; | |
241 | } | |
242 | } else | |
243 | ds1307->type = ds_1307; | |
244 | ||
245 | read_rtc: | |
246 | /* read RTC registers */ | |
247 | ||
248 | tmp = i2c_transfer(client->adapter, ds1307->msg, 2); | |
249 | if (tmp != 2) { | |
250 | pr_debug("read error %d\n", tmp); | |
251 | err = -EIO; | |
252 | goto exit_free; | |
253 | } | |
254 | ||
255 | /* minimal sanity checking; some chips (like DS1340) don't | |
256 | * specify the extra bits as must-be-zero, but there are | |
257 | * still a few values that are clearly out-of-range. | |
258 | */ | |
259 | tmp = ds1307->regs[DS1307_REG_SECS]; | |
260 | if (tmp & DS1307_BIT_CH) { | |
261 | if (ds1307->type && ds1307->type != ds_1307) { | |
262 | pr_debug("not a ds1307?\n"); | |
263 | goto exit_free; | |
264 | } | |
265 | ds1307->type = ds_1307; | |
266 | ||
267 | /* this partial initialization should work for ds1307, | |
268 | * ds1338, ds1340, st m41t00, and more. | |
269 | */ | |
270 | dev_warn(&client->dev, "oscillator started; SET TIME!\n"); | |
271 | i2c_smbus_write_byte_data(client, 0, 0); | |
272 | goto read_rtc; | |
273 | } | |
274 | tmp = BCD2BIN(tmp & 0x7f); | |
275 | if (tmp > 60) | |
276 | goto exit_free; | |
277 | tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f); | |
278 | if (tmp > 60) | |
279 | goto exit_free; | |
280 | ||
281 | tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f); | |
282 | if (tmp == 0 || tmp > 31) | |
283 | goto exit_free; | |
284 | ||
285 | tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f); | |
286 | if (tmp == 0 || tmp > 12) | |
287 | goto exit_free; | |
288 | ||
289 | /* force into in 24 hour mode (most chips) or | |
290 | * disable century bit (ds1340) | |
291 | */ | |
292 | tmp = ds1307->regs[DS1307_REG_HOUR]; | |
293 | if (tmp & (1 << 6)) { | |
294 | if (tmp & (1 << 5)) | |
295 | tmp = BCD2BIN(tmp & 0x1f) + 12; | |
296 | else | |
297 | tmp = BCD2BIN(tmp); | |
298 | i2c_smbus_write_byte_data(client, | |
299 | DS1307_REG_HOUR, | |
300 | BIN2BCD(tmp)); | |
301 | } | |
302 | ||
303 | /* FIXME chips like 1337 can generate alarm irqs too; those are | |
304 | * worth exposing through the API (especially when the irq is | |
305 | * wakeup-capable). | |
306 | */ | |
307 | ||
308 | switch (ds1307->type) { | |
309 | case unknown: | |
310 | strlcpy(client->name, "unknown", I2C_NAME_SIZE); | |
311 | break; | |
312 | case ds_1307: | |
313 | strlcpy(client->name, "ds1307", I2C_NAME_SIZE); | |
314 | break; | |
315 | case ds_1337: | |
316 | strlcpy(client->name, "ds1337", I2C_NAME_SIZE); | |
317 | break; | |
318 | case ds_1340: | |
319 | strlcpy(client->name, "ds1340", I2C_NAME_SIZE); | |
320 | break; | |
321 | } | |
322 | ||
323 | /* Tell the I2C layer a new client has arrived */ | |
324 | if ((err = i2c_attach_client(client))) | |
325 | goto exit_free; | |
326 | ||
327 | ds1307->rtc = rtc_device_register(client->name, &client->dev, | |
328 | &ds13xx_rtc_ops, THIS_MODULE); | |
329 | if (IS_ERR(ds1307->rtc)) { | |
330 | err = PTR_ERR(ds1307->rtc); | |
331 | dev_err(&client->dev, | |
332 | "unable to register the class device\n"); | |
333 | goto exit_detach; | |
334 | } | |
335 | ||
336 | return 0; | |
337 | ||
338 | exit_detach: | |
339 | i2c_detach_client(client); | |
340 | exit_free: | |
341 | kfree(ds1307); | |
342 | exit: | |
343 | return err; | |
344 | } | |
345 | ||
346 | static int __devinit | |
347 | ds1307_attach_adapter(struct i2c_adapter *adapter) | |
348 | { | |
349 | if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) | |
350 | return 0; | |
351 | return i2c_probe(adapter, &addr_data, ds1307_detect); | |
352 | } | |
353 | ||
354 | static int __devexit ds1307_detach_client(struct i2c_client *client) | |
355 | { | |
356 | int err; | |
357 | struct ds1307 *ds1307 = i2c_get_clientdata(client); | |
358 | ||
359 | rtc_device_unregister(ds1307->rtc); | |
360 | if ((err = i2c_detach_client(client))) | |
361 | return err; | |
362 | kfree(ds1307); | |
363 | return 0; | |
364 | } | |
365 | ||
366 | static struct i2c_driver ds1307_driver = { | |
367 | .driver = { | |
368 | .name = "ds1307", | |
369 | .owner = THIS_MODULE, | |
370 | }, | |
371 | .attach_adapter = ds1307_attach_adapter, | |
372 | .detach_client = __devexit_p(ds1307_detach_client), | |
373 | }; | |
374 | ||
375 | static int __init ds1307_init(void) | |
376 | { | |
377 | return i2c_add_driver(&ds1307_driver); | |
378 | } | |
379 | module_init(ds1307_init); | |
380 | ||
381 | static void __exit ds1307_exit(void) | |
382 | { | |
383 | i2c_del_driver(&ds1307_driver); | |
384 | } | |
385 | module_exit(ds1307_exit); | |
386 | ||
387 | MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips"); | |
388 | MODULE_LICENSE("GPL"); |