1 /*
2 * An I2C driver for the Epson RX8581 RTC
3 *
4 * Author: Martyn Welch <martyn.welch@gefanuc.com>
5 * Copyright 2008 GE Fanuc Intelligent Platforms Embedded Systems, Inc.
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 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
12 * Copyright 2005-06 Tower Technologies
13 */
14
15 #include <linux/module.h>
16 #include <linux/i2c.h>
17 #include <linux/bcd.h>
18 #include <linux/rtc.h>
19 #include <linux/log2.h>
20
21 #define DRV_VERSION "0.1"
22
23 #define RX8581_REG_SC 0x00 /* Second in BCD */
24 #define RX8581_REG_MN 0x01 /* Minute in BCD */
25 #define RX8581_REG_HR 0x02 /* Hour in BCD */
26 #define RX8581_REG_DW 0x03 /* Day of Week */
27 #define RX8581_REG_DM 0x04 /* Day of Month in BCD */
28 #define RX8581_REG_MO 0x05 /* Month in BCD */
29 #define RX8581_REG_YR 0x06 /* Year in BCD */
30 #define RX8581_REG_RAM 0x07 /* RAM */
31 #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/
32 #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */
33 #define RX8581_REG_ADM 0x0A
34 #define RX8581_REG_ADW 0x0A
35 #define RX8581_REG_TMR0 0x0B
36 #define RX8581_REG_TMR1 0x0C
37 #define RX8581_REG_EXT 0x0D /* Extension Register */
38 #define RX8581_REG_FLAG 0x0E /* Flag Register */
39 #define RX8581_REG_CTRL 0x0F /* Control Register */
40
41
42 /* Flag Register bit definitions */
43 #define RX8581_FLAG_UF 0x20 /* Update */
44 #define RX8581_FLAG_TF 0x10 /* Timer */
45 #define RX8581_FLAG_AF 0x08 /* Alarm */
46 #define RX8581_FLAG_VLF 0x02 /* Voltage Low */
47
48 /* Control Register bit definitions */
49 #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */
50 #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */
51 #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */
52 #define RX8581_CTRL_STOP 0x02 /* STOP bit */
53 #define RX8581_CTRL_RESET 0x01 /* RESET bit */
54
55 static struct i2c_driver rx8581_driver;
56
57 /*
58 * In the routines that deal directly with the rx8581 hardware, we use
59 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
60 */
61 static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
62 {
63 unsigned char date[7];
64 int data, err;
65
66 /* First we ensure that the "update flag" is not set, we read the
67 * time and date then re-read the "update flag". If the update flag
68 * has been set, we know that the time has changed during the read so
69 * we repeat the whole process again.
70 */
71 data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
72 if (data < 0) {
73 dev_err(&client->dev, "Unable to read device flags\n");
74 return -EIO;
75 }
76
77 do {
78 /* If update flag set, clear it */
79 if (data & RX8581_FLAG_UF) {
80 err = i2c_smbus_write_byte_data(client,
81 RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF));
82 if (err != 0) {
83 dev_err(&client->dev, "Unable to write device "
84 "flags\n");
85 return -EIO;
86 }
87 }
88
89 /* Now read time and date */
90 err = i2c_smbus_read_i2c_block_data(client, RX8581_REG_SC,
91 7, date);
92 if (err < 0) {
93 dev_err(&client->dev, "Unable to read date\n");
94 return -EIO;
95 }
96
97 /* Check flag register */
98 data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
99 if (data < 0) {
100 dev_err(&client->dev, "Unable to read device flags\n");
101 return -EIO;
102 }
103 } while (data & RX8581_FLAG_UF);
104
105 if (data & RX8581_FLAG_VLF)
106 dev_info(&client->dev,
107 "low voltage detected, date/time is not reliable.\n");
108
109 dev_dbg(&client->dev,
110 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
111 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
112 __func__,
113 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
114
115 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
116 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
117 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
118 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
119 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
120 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
121 tm->tm_year = bcd2bin(date[RX8581_REG_YR]);
122 if (tm->tm_year < 70)
123 tm->tm_year += 100; /* assume we are in 1970...2069 */
124
125
126 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
127 "mday=%d, mon=%d, year=%d, wday=%d\n",
128 __func__,
129 tm->tm_sec, tm->tm_min, tm->tm_hour,
130 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
131
132 err = rtc_valid_tm(tm);
133 if (err < 0)
134 dev_err(&client->dev, "retrieved date/time is not valid.\n");
135
136 return err;
137 }
138
139 static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
140 {
141 int data, err;
142 unsigned char buf[7];
143
144 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
145 "mday=%d, mon=%d, year=%d, wday=%d\n",
146 __func__,
147 tm->tm_sec, tm->tm_min, tm->tm_hour,
148 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
149
150 /* hours, minutes and seconds */
151 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
152 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
153 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
154
155 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
156
157 /* month, 1 - 12 */
158 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
159
160 /* year and century */
161 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100);
162 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
163
164 /* Stop the clock */
165 data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
166 if (data < 0) {
167 dev_err(&client->dev, "Unable to read control register\n");
168 return -EIO;
169 }
170
171 err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG,
172 (data | RX8581_CTRL_STOP));
173 if (err < 0) {
174 dev_err(&client->dev, "Unable to write control register\n");
175 return -EIO;
176 }
177
178 /* write register's data */
179 err = i2c_smbus_write_i2c_block_data(client, RX8581_REG_SC, 7, buf);
180 if (err < 0) {
181 dev_err(&client->dev, "Unable to write to date registers\n");
182 return -EIO;
183 }
184
185 /* Restart the clock */
186 data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
187 if (data < 0) {
188 dev_err(&client->dev, "Unable to read control register\n");
189 return -EIO;
190 }
191
192 err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG,
193 (data | ~(RX8581_CTRL_STOP)));
194 if (err != 0) {
195 dev_err(&client->dev, "Unable to write control register\n");
196 return -EIO;
197 }
198
199 return 0;
200 }
201
202 static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
203 {
204 return rx8581_get_datetime(to_i2c_client(dev), tm);
205 }
206
207 static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
208 {
209 return rx8581_set_datetime(to_i2c_client(dev), tm);
210 }
211
212 static const struct rtc_class_ops rx8581_rtc_ops = {
213 .read_time = rx8581_rtc_read_time,
214 .set_time = rx8581_rtc_set_time,
215 };
216
217 static int __devinit rx8581_probe(struct i2c_client *client,
218 const struct i2c_device_id *id)
219 {
220 struct rtc_device *rtc;
221
222 dev_dbg(&client->dev, "%s\n", __func__);
223
224 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
225 return -ENODEV;
226
227 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
228
229 rtc = rtc_device_register(rx8581_driver.driver.name,
230 &client->dev, &rx8581_rtc_ops, THIS_MODULE);
231
232 if (IS_ERR(rtc))
233 return PTR_ERR(rtc);
234
235 i2c_set_clientdata(client, rtc);
236
237 return 0;
238 }
239
240 static int __devexit rx8581_remove(struct i2c_client *client)
241 {
242 struct rtc_device *rtc = i2c_get_clientdata(client);
243
244 rtc_device_unregister(rtc);
245
246 return 0;
247 }
248
249 static const struct i2c_device_id rx8581_id[] = {
250 { "rx8581", 0 },
251 { }
252 };
253 MODULE_DEVICE_TABLE(i2c, rx8581_id);
254
255 static struct i2c_driver rx8581_driver = {
256 .driver = {
257 .name = "rtc-rx8581",
258 .owner = THIS_MODULE,
259 },
260 .probe = rx8581_probe,
261 .remove = __devexit_p(rx8581_remove),
262 .id_table = rx8581_id,
263 };
264
265 static int __init rx8581_init(void)
266 {
267 return i2c_add_driver(&rx8581_driver);
268 }
269
270 static void __exit rx8581_exit(void)
271 {
272 i2c_del_driver(&rx8581_driver);
273 }
274
275 MODULE_AUTHOR("Martyn Welch <martyn.welch@gefanuc.com>");
276 MODULE_DESCRIPTION("Epson RX-8581 RTC driver");
277 MODULE_LICENSE("GPL");
278 MODULE_VERSION(DRV_VERSION);
279
280 module_init(rx8581_init);
281 module_exit(rx8581_exit);
282
|
This page was automatically generated by the
LXR engine.
|