diff options
Diffstat (limited to 'drivers/rtc/rtc-rx8581.c')
-rw-r--r-- | drivers/rtc/rtc-rx8581.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rx8581.c b/drivers/rtc/rtc-rx8581.c new file mode 100644 index 00000000000..c9522f3bc21 --- /dev/null +++ b/drivers/rtc/rtc-rx8581.c | |||
@@ -0,0 +1,281 @@ | |||
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); | ||