Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
rtc-max8998.c
Go to the documentation of this file.
1 /*
2  * RTC driver for Maxim MAX8998
3  *
4  * Copyright (C) 2010 Samsung Electronics Co.Ltd
5  * Author: Minkyu Kang <[email protected]>
6  * Author: Joonyoung Shim <[email protected]>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the
10  * Free Software Foundation; either version 2 of the License, or (at your
11  * option) any later version.
12  *
13  */
14 
15 #include <linux/module.h>
16 #include <linux/i2c.h>
17 #include <linux/slab.h>
18 #include <linux/bcd.h>
19 #include <linux/rtc.h>
20 #include <linux/platform_device.h>
21 #include <linux/mfd/max8998.h>
22 #include <linux/mfd/max8998-private.h>
23 #include <linux/delay.h>
24 
25 #define MAX8998_RTC_SEC 0x00
26 #define MAX8998_RTC_MIN 0x01
27 #define MAX8998_RTC_HOUR 0x02
28 #define MAX8998_RTC_WEEKDAY 0x03
29 #define MAX8998_RTC_DATE 0x04
30 #define MAX8998_RTC_MONTH 0x05
31 #define MAX8998_RTC_YEAR1 0x06
32 #define MAX8998_RTC_YEAR2 0x07
33 #define MAX8998_ALARM0_SEC 0x08
34 #define MAX8998_ALARM0_MIN 0x09
35 #define MAX8998_ALARM0_HOUR 0x0a
36 #define MAX8998_ALARM0_WEEKDAY 0x0b
37 #define MAX8998_ALARM0_DATE 0x0c
38 #define MAX8998_ALARM0_MONTH 0x0d
39 #define MAX8998_ALARM0_YEAR1 0x0e
40 #define MAX8998_ALARM0_YEAR2 0x0f
41 #define MAX8998_ALARM1_SEC 0x10
42 #define MAX8998_ALARM1_MIN 0x11
43 #define MAX8998_ALARM1_HOUR 0x12
44 #define MAX8998_ALARM1_WEEKDAY 0x13
45 #define MAX8998_ALARM1_DATE 0x14
46 #define MAX8998_ALARM1_MONTH 0x15
47 #define MAX8998_ALARM1_YEAR1 0x16
48 #define MAX8998_ALARM1_YEAR2 0x17
49 #define MAX8998_ALARM0_CONF 0x18
50 #define MAX8998_ALARM1_CONF 0x19
51 #define MAX8998_RTC_STATUS 0x1a
52 #define MAX8998_WTSR_SMPL_CNTL 0x1b
53 #define MAX8998_TEST 0x1f
54 
55 #define HOUR_12 (1 << 7)
56 #define HOUR_PM (1 << 5)
57 #define ALARM0_STATUS (1 << 1)
58 #define ALARM1_STATUS (1 << 2)
59 
60 enum {
61  RTC_SEC = 0,
62  RTC_MIN,
63  RTC_HOUR,
64  RTC_WEEKDAY,
65  RTC_DATE,
66  RTC_MONTH,
67  RTC_YEAR1,
68  RTC_YEAR2,
69 };
70 
71 struct max8998_rtc_info {
72  struct device *dev;
73  struct max8998_dev *max8998;
74  struct i2c_client *rtc;
75  struct rtc_device *rtc_dev;
76  int irq;
77  bool lp3974_bug_workaround;
78 };
79 
80 static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
81 {
82  tm->tm_sec = bcd2bin(data[RTC_SEC]);
83  tm->tm_min = bcd2bin(data[RTC_MIN]);
84  if (data[RTC_HOUR] & HOUR_12) {
85  tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);
86  if (data[RTC_HOUR] & HOUR_PM)
87  tm->tm_hour += 12;
88  } else
89  tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
90 
91  tm->tm_wday = data[RTC_WEEKDAY] & 0x07;
92  tm->tm_mday = bcd2bin(data[RTC_DATE]);
93  tm->tm_mon = bcd2bin(data[RTC_MONTH]);
94  tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;
95  tm->tm_year -= 1900;
96 }
97 
98 static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)
99 {
100  data[RTC_SEC] = bin2bcd(tm->tm_sec);
101  data[RTC_MIN] = bin2bcd(tm->tm_min);
102  data[RTC_HOUR] = bin2bcd(tm->tm_hour);
103  data[RTC_WEEKDAY] = tm->tm_wday;
104  data[RTC_DATE] = bin2bcd(tm->tm_mday);
105  data[RTC_MONTH] = bin2bcd(tm->tm_mon);
106  data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);
107  data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
108 }
109 
110 static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)
111 {
112  struct max8998_rtc_info *info = dev_get_drvdata(dev);
113  u8 data[8];
114  int ret;
115 
116  ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);
117  if (ret < 0)
118  return ret;
119 
120  max8998_data_to_tm(data, tm);
121 
122  return rtc_valid_tm(tm);
123 }
124 
125 static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)
126 {
127  struct max8998_rtc_info *info = dev_get_drvdata(dev);
128  u8 data[8];
129  int ret;
130 
131  max8998_tm_to_data(tm, data);
132 
133  ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
134 
135  if (info->lp3974_bug_workaround)
136  msleep(2000);
137 
138  return ret;
139 }
140 
141 static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
142 {
143  struct max8998_rtc_info *info = dev_get_drvdata(dev);
144  u8 data[8];
145  u8 val;
146  int ret;
147 
148  ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);
149  if (ret < 0)
150  return ret;
151 
152  max8998_data_to_tm(data, &alrm->time);
153 
154  ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);
155  if (ret < 0)
156  return ret;
157 
158  alrm->enabled = !!val;
159 
160  ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);
161  if (ret < 0)
162  return ret;
163 
164  if (val & ALARM0_STATUS)
165  alrm->pending = 1;
166  else
167  alrm->pending = 0;
168 
169  return 0;
170 }
171 
172 static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
173 {
174  int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
175 
176  if (info->lp3974_bug_workaround)
177  msleep(2000);
178 
179  return ret;
180 }
181 
182 static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
183 {
184  int ret;
185  u8 alarm0_conf = 0x77;
186 
187  /* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */
188  if (info->lp3974_bug_workaround)
189  alarm0_conf = 0x57;
190 
191  ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);
192 
193  if (info->lp3974_bug_workaround)
194  msleep(2000);
195 
196  return ret;
197 }
198 
199 static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
200 {
201  struct max8998_rtc_info *info = dev_get_drvdata(dev);
202  u8 data[8];
203  int ret;
204 
205  max8998_tm_to_data(&alrm->time, data);
206 
207  ret = max8998_rtc_stop_alarm(info);
208  if (ret < 0)
209  return ret;
210 
211  ret = max8998_bulk_write(info->rtc, MAX8998_ALARM0_SEC, 8, data);
212  if (ret < 0)
213  return ret;
214 
215  if (info->lp3974_bug_workaround)
216  msleep(2000);
217 
218  if (alrm->enabled)
219  ret = max8998_rtc_start_alarm(info);
220 
221  return ret;
222 }
223 
224 static int max8998_rtc_alarm_irq_enable(struct device *dev,
225  unsigned int enabled)
226 {
227  struct max8998_rtc_info *info = dev_get_drvdata(dev);
228 
229  if (enabled)
230  return max8998_rtc_start_alarm(info);
231  else
232  return max8998_rtc_stop_alarm(info);
233 }
234 
235 static irqreturn_t max8998_rtc_alarm_irq(int irq, void *data)
236 {
237  struct max8998_rtc_info *info = data;
238 
239  rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
240 
241  return IRQ_HANDLED;
242 }
243 
244 static const struct rtc_class_ops max8998_rtc_ops = {
245  .read_time = max8998_rtc_read_time,
246  .set_time = max8998_rtc_set_time,
247  .read_alarm = max8998_rtc_read_alarm,
248  .set_alarm = max8998_rtc_set_alarm,
249  .alarm_irq_enable = max8998_rtc_alarm_irq_enable,
250 };
251 
252 static int __devinit max8998_rtc_probe(struct platform_device *pdev)
253 {
254  struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
255  struct max8998_platform_data *pdata = dev_get_platdata(max8998->dev);
256  struct max8998_rtc_info *info;
257  int ret;
258 
259  info = kzalloc(sizeof(struct max8998_rtc_info), GFP_KERNEL);
260  if (!info)
261  return -ENOMEM;
262 
263  info->dev = &pdev->dev;
264  info->max8998 = max8998;
265  info->rtc = max8998->rtc;
266  info->irq = max8998->irq_base + MAX8998_IRQ_ALARM0;
267 
268  platform_set_drvdata(pdev, info);
269 
270  info->rtc_dev = rtc_device_register("max8998-rtc", &pdev->dev,
271  &max8998_rtc_ops, THIS_MODULE);
272 
273  if (IS_ERR(info->rtc_dev)) {
274  ret = PTR_ERR(info->rtc_dev);
275  dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
276  goto out_rtc;
277  }
278 
279  ret = request_threaded_irq(info->irq, NULL, max8998_rtc_alarm_irq, 0,
280  "rtc-alarm0", info);
281 
282  if (ret < 0)
283  dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
284  info->irq, ret);
285 
286  dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);
287  if (pdata->rtc_delay) {
288  info->lp3974_bug_workaround = true;
289  dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
290  " RTC updates will be extremely slow.\n");
291  }
292 
293  return 0;
294 
295 out_rtc:
296  platform_set_drvdata(pdev, NULL);
297  kfree(info);
298  return ret;
299 }
300 
301 static int __devexit max8998_rtc_remove(struct platform_device *pdev)
302 {
303  struct max8998_rtc_info *info = platform_get_drvdata(pdev);
304 
305  if (info) {
306  free_irq(info->irq, info);
307  rtc_device_unregister(info->rtc_dev);
308  kfree(info);
309  }
310 
311  return 0;
312 }
313 
314 static const struct platform_device_id max8998_rtc_id[] = {
315  { "max8998-rtc", TYPE_MAX8998 },
316  { "lp3974-rtc", TYPE_LP3974 },
317  { }
318 };
319 
320 static struct platform_driver max8998_rtc_driver = {
321  .driver = {
322  .name = "max8998-rtc",
323  .owner = THIS_MODULE,
324  },
325  .probe = max8998_rtc_probe,
326  .remove = __devexit_p(max8998_rtc_remove),
327  .id_table = max8998_rtc_id,
328 };
329 
330 module_platform_driver(max8998_rtc_driver);
331 
332 MODULE_AUTHOR("Minkyu Kang <[email protected]>");
333 MODULE_AUTHOR("Joonyoung Shim <[email protected]>");
334 MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
335 MODULE_LICENSE("GPL");
Generated on Thu Jan 10 2013 14:16:54 for Linux Kernel by   doxygen 1.8.2