Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
rtc-rv3029c2.c
Go to the documentation of this file.
1 /*
2  * Micro Crystal RV-3029C2 rtc class driver
3  *
4  * Author: Gregory Hermant <[email protected]>
5  *
6  * based on previously existing rtc class drivers
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  *
12  * NOTE: Currently this driver only supports the bare minimum for read
13  * and write the RTC and alarms. The extra features provided by this chip
14  * (trickle charger, eeprom, T° compensation) are unavailable.
15  */
16 
17 #include <linux/module.h>
18 #include <linux/i2c.h>
19 #include <linux/bcd.h>
20 #include <linux/rtc.h>
21 
22 /* Register map */
23 /* control section */
24 #define RV3029C2_ONOFF_CTRL 0x00
25 #define RV3029C2_IRQ_CTRL 0x01
26 #define RV3029C2_IRQ_CTRL_AIE (1 << 0)
27 #define RV3029C2_IRQ_FLAGS 0x02
28 #define RV3029C2_IRQ_FLAGS_AF (1 << 0)
29 #define RV3029C2_STATUS 0x03
30 #define RV3029C2_STATUS_VLOW1 (1 << 2)
31 #define RV3029C2_STATUS_VLOW2 (1 << 3)
32 #define RV3029C2_STATUS_SR (1 << 4)
33 #define RV3029C2_STATUS_PON (1 << 5)
34 #define RV3029C2_STATUS_EEBUSY (1 << 7)
35 #define RV3029C2_RST_CTRL 0x04
36 #define RV3029C2_CONTROL_SECTION_LEN 0x05
37 
38 /* watch section */
39 #define RV3029C2_W_SEC 0x08
40 #define RV3029C2_W_MINUTES 0x09
41 #define RV3029C2_W_HOURS 0x0A
42 #define RV3029C2_REG_HR_12_24 (1<<6) /* 24h/12h mode */
43 #define RV3029C2_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
44 #define RV3029C2_W_DATE 0x0B
45 #define RV3029C2_W_DAYS 0x0C
46 #define RV3029C2_W_MONTHS 0x0D
47 #define RV3029C2_W_YEARS 0x0E
48 #define RV3029C2_WATCH_SECTION_LEN 0x07
49 
50 /* alarm section */
51 #define RV3029C2_A_SC 0x10
52 #define RV3029C2_A_MN 0x11
53 #define RV3029C2_A_HR 0x12
54 #define RV3029C2_A_DT 0x13
55 #define RV3029C2_A_DW 0x14
56 #define RV3029C2_A_MO 0x15
57 #define RV3029C2_A_YR 0x16
58 #define RV3029C2_ALARM_SECTION_LEN 0x07
59 
60 /* timer section */
61 #define RV3029C2_TIMER_LOW 0x18
62 #define RV3029C2_TIMER_HIGH 0x19
63 
64 /* temperature section */
65 #define RV3029C2_TEMP_PAGE 0x20
66 
67 /* eeprom data section */
68 #define RV3029C2_E2P_EEDATA1 0x28
69 #define RV3029C2_E2P_EEDATA2 0x29
70 
71 /* eeprom control section */
72 #define RV3029C2_CONTROL_E2P_EECTRL 0x30
73 #define RV3029C2_TRICKLE_1K (1<<0) /* 1K resistance */
74 #define RV3029C2_TRICKLE_5K (1<<1) /* 5K resistance */
75 #define RV3029C2_TRICKLE_20K (1<<2) /* 20K resistance */
76 #define RV3029C2_TRICKLE_80K (1<<3) /* 80K resistance */
77 #define RV3029C2_CONTROL_E2P_XTALOFFSET 0x31
78 #define RV3029C2_CONTROL_E2P_QCOEF 0x32
79 #define RV3029C2_CONTROL_E2P_TURNOVER 0x33
80 
81 /* user ram section */
82 #define RV3029C2_USR1_RAM_PAGE 0x38
83 #define RV3029C2_USR1_SECTION_LEN 0x04
84 #define RV3029C2_USR2_RAM_PAGE 0x3C
85 #define RV3029C2_USR2_SECTION_LEN 0x04
86 
87 static int
88 rv3029c2_i2c_read_regs(struct i2c_client *client, u8 reg, u8 *buf,
89  unsigned len)
90 {
91  int ret;
92 
93  if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
94  (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
95  return -EINVAL;
96 
97  ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
98  if (ret < 0)
99  return ret;
100  if (ret < len)
101  return -EIO;
102  return 0;
103 }
104 
105 static int
106 rv3029c2_i2c_write_regs(struct i2c_client *client, u8 reg, u8 const buf[],
107  unsigned len)
108 {
109  if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
110  (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
111  return -EINVAL;
112 
113  return i2c_smbus_write_i2c_block_data(client, reg, len, buf);
114 }
115 
116 static int
117 rv3029c2_i2c_get_sr(struct i2c_client *client, u8 *buf)
118 {
119  int ret = rv3029c2_i2c_read_regs(client, RV3029C2_STATUS, buf, 1);
120 
121  if (ret < 0)
122  return -EIO;
123  dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
124  return 0;
125 }
126 
127 static int
128 rv3029c2_i2c_set_sr(struct i2c_client *client, u8 val)
129 {
130  u8 buf[1];
131  int sr;
132 
133  buf[0] = val;
134  sr = rv3029c2_i2c_write_regs(client, RV3029C2_STATUS, buf, 1);
135  dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
136  if (sr < 0)
137  return -EIO;
138  return 0;
139 }
140 
141 static int
142 rv3029c2_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
143 {
144  u8 buf[1];
145  int ret;
146  u8 regs[RV3029C2_WATCH_SECTION_LEN] = { 0, };
147 
148  ret = rv3029c2_i2c_get_sr(client, buf);
149  if (ret < 0) {
150  dev_err(&client->dev, "%s: reading SR failed\n", __func__);
151  return -EIO;
152  }
153 
154  ret = rv3029c2_i2c_read_regs(client, RV3029C2_W_SEC , regs,
155  RV3029C2_WATCH_SECTION_LEN);
156  if (ret < 0) {
157  dev_err(&client->dev, "%s: reading RTC section failed\n",
158  __func__);
159  return ret;
160  }
161 
162  tm->tm_sec = bcd2bin(regs[RV3029C2_W_SEC-RV3029C2_W_SEC]);
163  tm->tm_min = bcd2bin(regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC]);
164 
165  /* HR field has a more complex interpretation */
166  {
167  const u8 _hr = regs[RV3029C2_W_HOURS-RV3029C2_W_SEC];
168  if (_hr & RV3029C2_REG_HR_12_24) {
169  /* 12h format */
170  tm->tm_hour = bcd2bin(_hr & 0x1f);
171  if (_hr & RV3029C2_REG_HR_PM) /* PM flag set */
172  tm->tm_hour += 12;
173  } else /* 24h format */
174  tm->tm_hour = bcd2bin(_hr & 0x3f);
175  }
176 
177  tm->tm_mday = bcd2bin(regs[RV3029C2_W_DATE-RV3029C2_W_SEC]);
178  tm->tm_mon = bcd2bin(regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC]) - 1;
179  tm->tm_year = bcd2bin(regs[RV3029C2_W_YEARS-RV3029C2_W_SEC]) + 100;
180  tm->tm_wday = bcd2bin(regs[RV3029C2_W_DAYS-RV3029C2_W_SEC]) - 1;
181 
182  return 0;
183 }
184 
185 static int rv3029c2_rtc_read_time(struct device *dev, struct rtc_time *tm)
186 {
187  return rv3029c2_i2c_read_time(to_i2c_client(dev), tm);
188 }
189 
190 static int
191 rv3029c2_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
192 {
193  struct rtc_time *const tm = &alarm->time;
194  int ret;
195  u8 regs[8];
196 
197  ret = rv3029c2_i2c_get_sr(client, regs);
198  if (ret < 0) {
199  dev_err(&client->dev, "%s: reading SR failed\n", __func__);
200  return -EIO;
201  }
202 
203  ret = rv3029c2_i2c_read_regs(client, RV3029C2_A_SC, regs,
204  RV3029C2_ALARM_SECTION_LEN);
205 
206  if (ret < 0) {
207  dev_err(&client->dev, "%s: reading alarm section failed\n",
208  __func__);
209  return ret;
210  }
211 
212  tm->tm_sec = bcd2bin(regs[RV3029C2_A_SC-RV3029C2_A_SC] & 0x7f);
213  tm->tm_min = bcd2bin(regs[RV3029C2_A_MN-RV3029C2_A_SC] & 0x7f);
214  tm->tm_hour = bcd2bin(regs[RV3029C2_A_HR-RV3029C2_A_SC] & 0x3f);
215  tm->tm_mday = bcd2bin(regs[RV3029C2_A_DT-RV3029C2_A_SC] & 0x3f);
216  tm->tm_mon = bcd2bin(regs[RV3029C2_A_MO-RV3029C2_A_SC] & 0x1f) - 1;
217  tm->tm_year = bcd2bin(regs[RV3029C2_A_YR-RV3029C2_A_SC] & 0x7f) + 100;
218  tm->tm_wday = bcd2bin(regs[RV3029C2_A_DW-RV3029C2_A_SC] & 0x07) - 1;
219 
220  return 0;
221 }
222 
223 static int
224 rv3029c2_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
225 {
226  return rv3029c2_i2c_read_alarm(to_i2c_client(dev), alarm);
227 }
228 
229 static int rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client *client,
230  int enable)
231 {
232  int ret;
233  u8 buf[1];
234 
235  /* enable AIE irq */
236  ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
237  if (ret < 0) {
238  dev_err(&client->dev, "can't read INT reg\n");
239  return ret;
240  }
241  if (enable)
242  buf[0] |= RV3029C2_IRQ_CTRL_AIE;
243  else
244  buf[0] &= ~RV3029C2_IRQ_CTRL_AIE;
245 
246  ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
247  if (ret < 0) {
248  dev_err(&client->dev, "can't set INT reg\n");
249  return ret;
250  }
251 
252  return 0;
253 }
254 
255 static int rv3029c2_rtc_i2c_set_alarm(struct i2c_client *client,
256  struct rtc_wkalrm *alarm)
257 {
258  struct rtc_time *const tm = &alarm->time;
259  int ret;
260  u8 regs[8];
261 
262  /*
263  * The clock has an 8 bit wide bcd-coded register (they never learn)
264  * for the year. tm_year is an offset from 1900 and we are interested
265  * in the 2000-2099 range, so any value less than 100 is invalid.
266  */
267  if (tm->tm_year < 100)
268  return -EINVAL;
269 
270  ret = rv3029c2_i2c_get_sr(client, regs);
271  if (ret < 0) {
272  dev_err(&client->dev, "%s: reading SR failed\n", __func__);
273  return -EIO;
274  }
275  regs[RV3029C2_A_SC-RV3029C2_A_SC] = bin2bcd(tm->tm_sec & 0x7f);
276  regs[RV3029C2_A_MN-RV3029C2_A_SC] = bin2bcd(tm->tm_min & 0x7f);
277  regs[RV3029C2_A_HR-RV3029C2_A_SC] = bin2bcd(tm->tm_hour & 0x3f);
278  regs[RV3029C2_A_DT-RV3029C2_A_SC] = bin2bcd(tm->tm_mday & 0x3f);
279  regs[RV3029C2_A_MO-RV3029C2_A_SC] = bin2bcd((tm->tm_mon & 0x1f) - 1);
280  regs[RV3029C2_A_DW-RV3029C2_A_SC] = bin2bcd((tm->tm_wday & 7) - 1);
281  regs[RV3029C2_A_YR-RV3029C2_A_SC] = bin2bcd((tm->tm_year & 0x7f) - 100);
282 
283  ret = rv3029c2_i2c_write_regs(client, RV3029C2_A_SC, regs,
284  RV3029C2_ALARM_SECTION_LEN);
285  if (ret < 0)
286  return ret;
287 
288  if (alarm->enabled) {
289  u8 buf[1];
290 
291  /* clear AF flag */
292  ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_FLAGS,
293  buf, 1);
294  if (ret < 0) {
295  dev_err(&client->dev, "can't read alarm flag\n");
296  return ret;
297  }
298  buf[0] &= ~RV3029C2_IRQ_FLAGS_AF;
299  ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_FLAGS,
300  buf, 1);
301  if (ret < 0) {
302  dev_err(&client->dev, "can't set alarm flag\n");
303  return ret;
304  }
305  /* enable AIE irq */
306  ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
307  if (ret)
308  return ret;
309 
310  dev_dbg(&client->dev, "alarm IRQ armed\n");
311  } else {
312  /* disable AIE irq */
313  ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
314  if (ret)
315  return ret;
316 
317  dev_dbg(&client->dev, "alarm IRQ disabled\n");
318  }
319 
320  return 0;
321 }
322 
323 static int rv3029c2_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
324 {
325  return rv3029c2_rtc_i2c_set_alarm(to_i2c_client(dev), alarm);
326 }
327 
328 static int
329 rv3029c2_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
330 {
331  u8 regs[8];
332  int ret;
333 
334  /*
335  * The clock has an 8 bit wide bcd-coded register (they never learn)
336  * for the year. tm_year is an offset from 1900 and we are interested
337  * in the 2000-2099 range, so any value less than 100 is invalid.
338  */
339  if (tm->tm_year < 100)
340  return -EINVAL;
341 
342  regs[RV3029C2_W_SEC-RV3029C2_W_SEC] = bin2bcd(tm->tm_sec);
343  regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC] = bin2bcd(tm->tm_min);
344  regs[RV3029C2_W_HOURS-RV3029C2_W_SEC] = bin2bcd(tm->tm_hour);
345  regs[RV3029C2_W_DATE-RV3029C2_W_SEC] = bin2bcd(tm->tm_mday);
346  regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC] = bin2bcd(tm->tm_mon+1);
347  regs[RV3029C2_W_DAYS-RV3029C2_W_SEC] = bin2bcd((tm->tm_wday & 7)+1);
348  regs[RV3029C2_W_YEARS-RV3029C2_W_SEC] = bin2bcd(tm->tm_year - 100);
349 
350  ret = rv3029c2_i2c_write_regs(client, RV3029C2_W_SEC, regs,
351  RV3029C2_WATCH_SECTION_LEN);
352  if (ret < 0)
353  return ret;
354 
355  ret = rv3029c2_i2c_get_sr(client, regs);
356  if (ret < 0) {
357  dev_err(&client->dev, "%s: reading SR failed\n", __func__);
358  return ret;
359  }
360  /* clear PON bit */
361  ret = rv3029c2_i2c_set_sr(client, (regs[0] & ~RV3029C2_STATUS_PON));
362  if (ret < 0) {
363  dev_err(&client->dev, "%s: reading SR failed\n", __func__);
364  return ret;
365  }
366 
367  return 0;
368 }
369 
370 static int rv3029c2_rtc_set_time(struct device *dev, struct rtc_time *tm)
371 {
372  return rv3029c2_i2c_set_time(to_i2c_client(dev), tm);
373 }
374 
375 static const struct rtc_class_ops rv3029c2_rtc_ops = {
376  .read_time = rv3029c2_rtc_read_time,
377  .set_time = rv3029c2_rtc_set_time,
378  .read_alarm = rv3029c2_rtc_read_alarm,
379  .set_alarm = rv3029c2_rtc_set_alarm,
380 };
381 
382 static struct i2c_device_id rv3029c2_id[] = {
383  { "rv3029c2", 0 },
384  { }
385 };
386 MODULE_DEVICE_TABLE(i2c, rv3029c2_id);
387 
388 static int __devinit
389 rv3029c2_probe(struct i2c_client *client, const struct i2c_device_id *id)
390 {
391  struct rtc_device *rtc;
392  int rc = 0;
393  u8 buf[1];
394 
395  if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL))
396  return -ENODEV;
397 
398  rtc = rtc_device_register(client->name,
399  &client->dev, &rv3029c2_rtc_ops,
400  THIS_MODULE);
401 
402  if (IS_ERR(rtc))
403  return PTR_ERR(rtc);
404 
405  i2c_set_clientdata(client, rtc);
406 
407  rc = rv3029c2_i2c_get_sr(client, buf);
408  if (rc < 0) {
409  dev_err(&client->dev, "reading status failed\n");
410  goto exit_unregister;
411  }
412 
413  return 0;
414 
415 exit_unregister:
416  rtc_device_unregister(rtc);
417 
418  return rc;
419 }
420 
421 static int __devexit rv3029c2_remove(struct i2c_client *client)
422 {
423  struct rtc_device *rtc = i2c_get_clientdata(client);
424 
425  rtc_device_unregister(rtc);
426 
427  return 0;
428 }
429 
430 static struct i2c_driver rv3029c2_driver = {
431  .driver = {
432  .name = "rtc-rv3029c2",
433  },
434  .probe = rv3029c2_probe,
435  .remove = __devexit_p(rv3029c2_remove),
436  .id_table = rv3029c2_id,
437 };
438 
439 module_i2c_driver(rv3029c2_driver);
440 
441 MODULE_AUTHOR("Gregory Hermant <[email protected]>");
442 MODULE_DESCRIPTION("Micro Crystal RV3029C2 RTC driver");
443 MODULE_LICENSE("GPL");
Generated on Thu Jan 10 2013 14:16:59 for Linux Kernel by   doxygen 1.8.2