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a7fa9851 MW |
1 | /* |
2 | * An I2C driver for the Epson RX8581 RTC | |
3 | * | |
9756c4da MW |
4 | * Author: Martyn Welch <martyn.welch@ge.com> |
5 | * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. | |
a7fa9851 MW |
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 | ||
a7fa9851 MW |
21 | #define RX8581_REG_SC 0x00 /* Second in BCD */ |
22 | #define RX8581_REG_MN 0x01 /* Minute in BCD */ | |
23 | #define RX8581_REG_HR 0x02 /* Hour in BCD */ | |
24 | #define RX8581_REG_DW 0x03 /* Day of Week */ | |
25 | #define RX8581_REG_DM 0x04 /* Day of Month in BCD */ | |
26 | #define RX8581_REG_MO 0x05 /* Month in BCD */ | |
27 | #define RX8581_REG_YR 0x06 /* Year in BCD */ | |
28 | #define RX8581_REG_RAM 0x07 /* RAM */ | |
29 | #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/ | |
30 | #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */ | |
31 | #define RX8581_REG_ADM 0x0A | |
32 | #define RX8581_REG_ADW 0x0A | |
33 | #define RX8581_REG_TMR0 0x0B | |
34 | #define RX8581_REG_TMR1 0x0C | |
35 | #define RX8581_REG_EXT 0x0D /* Extension Register */ | |
36 | #define RX8581_REG_FLAG 0x0E /* Flag Register */ | |
37 | #define RX8581_REG_CTRL 0x0F /* Control Register */ | |
38 | ||
39 | ||
40 | /* Flag Register bit definitions */ | |
41 | #define RX8581_FLAG_UF 0x20 /* Update */ | |
42 | #define RX8581_FLAG_TF 0x10 /* Timer */ | |
43 | #define RX8581_FLAG_AF 0x08 /* Alarm */ | |
44 | #define RX8581_FLAG_VLF 0x02 /* Voltage Low */ | |
45 | ||
46 | /* Control Register bit definitions */ | |
47 | #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */ | |
48 | #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ | |
49 | #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ | |
50 | #define RX8581_CTRL_STOP 0x02 /* STOP bit */ | |
51 | #define RX8581_CTRL_RESET 0x01 /* RESET bit */ | |
52 | ||
d643a49a AW |
53 | struct rx8581 { |
54 | struct i2c_client *client; | |
55 | struct rtc_device *rtc; | |
56 | s32 (*read_block_data)(const struct i2c_client *client, u8 command, | |
57 | u8 length, u8 *values); | |
58 | s32 (*write_block_data)(const struct i2c_client *client, u8 command, | |
59 | u8 length, const u8 *values); | |
60 | }; | |
61 | ||
a7fa9851 MW |
62 | static struct i2c_driver rx8581_driver; |
63 | ||
d643a49a AW |
64 | static int rx8581_read_block_data(const struct i2c_client *client, u8 command, |
65 | u8 length, u8 *values) | |
66 | { | |
67 | s32 i, data; | |
68 | ||
69 | for (i = 0; i < length; i++) { | |
70 | data = i2c_smbus_read_byte_data(client, command + i); | |
71 | if (data < 0) | |
72 | return data; | |
73 | values[i] = data; | |
74 | } | |
75 | return i; | |
76 | } | |
77 | ||
78 | static int rx8581_write_block_data(const struct i2c_client *client, u8 command, | |
79 | u8 length, const u8 *values) | |
80 | { | |
81 | s32 i, ret; | |
82 | ||
83 | for (i = 0; i < length; i++) { | |
84 | ret = i2c_smbus_write_byte_data(client, command + i, | |
85 | values[i]); | |
86 | if (ret < 0) | |
87 | return ret; | |
88 | } | |
89 | return length; | |
90 | } | |
91 | ||
a7fa9851 MW |
92 | /* |
93 | * In the routines that deal directly with the rx8581 hardware, we use | |
94 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. | |
95 | */ | |
96 | static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm) | |
97 | { | |
98 | unsigned char date[7]; | |
99 | int data, err; | |
d643a49a | 100 | struct rx8581 *rx8581 = i2c_get_clientdata(client); |
a7fa9851 MW |
101 | |
102 | /* First we ensure that the "update flag" is not set, we read the | |
103 | * time and date then re-read the "update flag". If the update flag | |
104 | * has been set, we know that the time has changed during the read so | |
105 | * we repeat the whole process again. | |
106 | */ | |
107 | data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); | |
108 | if (data < 0) { | |
109 | dev_err(&client->dev, "Unable to read device flags\n"); | |
110 | return -EIO; | |
111 | } | |
112 | ||
113 | do { | |
114 | /* If update flag set, clear it */ | |
115 | if (data & RX8581_FLAG_UF) { | |
116 | err = i2c_smbus_write_byte_data(client, | |
117 | RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF)); | |
118 | if (err != 0) { | |
d643a49a | 119 | dev_err(&client->dev, "Unable to write device flags\n"); |
a7fa9851 MW |
120 | return -EIO; |
121 | } | |
122 | } | |
123 | ||
124 | /* Now read time and date */ | |
d643a49a | 125 | err = rx8581->read_block_data(client, RX8581_REG_SC, |
a7fa9851 MW |
126 | 7, date); |
127 | if (err < 0) { | |
128 | dev_err(&client->dev, "Unable to read date\n"); | |
129 | return -EIO; | |
130 | } | |
131 | ||
132 | /* Check flag register */ | |
133 | data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); | |
134 | if (data < 0) { | |
135 | dev_err(&client->dev, "Unable to read device flags\n"); | |
136 | return -EIO; | |
137 | } | |
138 | } while (data & RX8581_FLAG_UF); | |
139 | ||
140 | if (data & RX8581_FLAG_VLF) | |
141 | dev_info(&client->dev, | |
142 | "low voltage detected, date/time is not reliable.\n"); | |
143 | ||
144 | dev_dbg(&client->dev, | |
145 | "%s: raw data is sec=%02x, min=%02x, hr=%02x, " | |
146 | "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", | |
147 | __func__, | |
148 | date[0], date[1], date[2], date[3], date[4], date[5], date[6]); | |
149 | ||
150 | tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); | |
151 | tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); | |
152 | tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ | |
153 | tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); | |
154 | tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); | |
155 | tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ | |
156 | tm->tm_year = bcd2bin(date[RX8581_REG_YR]); | |
157 | if (tm->tm_year < 70) | |
158 | tm->tm_year += 100; /* assume we are in 1970...2069 */ | |
159 | ||
160 | ||
161 | dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " | |
162 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
163 | __func__, | |
164 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
165 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
166 | ||
167 | err = rtc_valid_tm(tm); | |
168 | if (err < 0) | |
169 | dev_err(&client->dev, "retrieved date/time is not valid.\n"); | |
170 | ||
171 | return err; | |
172 | } | |
173 | ||
174 | static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm) | |
175 | { | |
176 | int data, err; | |
177 | unsigned char buf[7]; | |
d643a49a | 178 | struct rx8581 *rx8581 = i2c_get_clientdata(client); |
a7fa9851 MW |
179 | |
180 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
181 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
182 | __func__, | |
183 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
184 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
185 | ||
186 | /* hours, minutes and seconds */ | |
187 | buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); | |
188 | buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); | |
189 | buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); | |
190 | ||
191 | buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); | |
192 | ||
193 | /* month, 1 - 12 */ | |
194 | buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); | |
195 | ||
196 | /* year and century */ | |
197 | buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100); | |
198 | buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); | |
199 | ||
200 | /* Stop the clock */ | |
201 | data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); | |
202 | if (data < 0) { | |
203 | dev_err(&client->dev, "Unable to read control register\n"); | |
204 | return -EIO; | |
205 | } | |
206 | ||
2884fce1 | 207 | err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, |
a7fa9851 MW |
208 | (data | RX8581_CTRL_STOP)); |
209 | if (err < 0) { | |
210 | dev_err(&client->dev, "Unable to write control register\n"); | |
211 | return -EIO; | |
212 | } | |
213 | ||
214 | /* write register's data */ | |
d643a49a | 215 | err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf); |
a7fa9851 MW |
216 | if (err < 0) { |
217 | dev_err(&client->dev, "Unable to write to date registers\n"); | |
218 | return -EIO; | |
219 | } | |
220 | ||
2884fce1 RM |
221 | /* get VLF and clear it */ |
222 | data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); | |
223 | if (data < 0) { | |
224 | dev_err(&client->dev, "Unable to read flag register\n"); | |
225 | return -EIO; | |
226 | } | |
227 | ||
228 | err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG, | |
229 | (data & ~(RX8581_FLAG_VLF))); | |
230 | if (err != 0) { | |
231 | dev_err(&client->dev, "Unable to write flag register\n"); | |
232 | return -EIO; | |
233 | } | |
234 | ||
a7fa9851 MW |
235 | /* Restart the clock */ |
236 | data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); | |
237 | if (data < 0) { | |
238 | dev_err(&client->dev, "Unable to read control register\n"); | |
239 | return -EIO; | |
240 | } | |
241 | ||
2884fce1 RM |
242 | err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, |
243 | (data & ~(RX8581_CTRL_STOP))); | |
a7fa9851 MW |
244 | if (err != 0) { |
245 | dev_err(&client->dev, "Unable to write control register\n"); | |
246 | return -EIO; | |
247 | } | |
248 | ||
249 | return 0; | |
250 | } | |
251 | ||
252 | static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
253 | { | |
254 | return rx8581_get_datetime(to_i2c_client(dev), tm); | |
255 | } | |
256 | ||
257 | static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
258 | { | |
259 | return rx8581_set_datetime(to_i2c_client(dev), tm); | |
260 | } | |
261 | ||
262 | static const struct rtc_class_ops rx8581_rtc_ops = { | |
263 | .read_time = rx8581_rtc_read_time, | |
264 | .set_time = rx8581_rtc_set_time, | |
265 | }; | |
266 | ||
5a167f45 GKH |
267 | static int rx8581_probe(struct i2c_client *client, |
268 | const struct i2c_device_id *id) | |
a7fa9851 | 269 | { |
d643a49a | 270 | struct rx8581 *rx8581; |
a7fa9851 MW |
271 | |
272 | dev_dbg(&client->dev, "%s\n", __func__); | |
273 | ||
d643a49a AW |
274 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA) |
275 | && !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) | |
276 | return -EIO; | |
a7fa9851 | 277 | |
d643a49a AW |
278 | rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL); |
279 | if (!rx8581) | |
280 | return -ENOMEM; | |
a7fa9851 | 281 | |
d643a49a AW |
282 | i2c_set_clientdata(client, rx8581); |
283 | rx8581->client = client; | |
a7fa9851 | 284 | |
d643a49a AW |
285 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) { |
286 | rx8581->read_block_data = i2c_smbus_read_i2c_block_data; | |
287 | rx8581->write_block_data = i2c_smbus_write_i2c_block_data; | |
288 | } else { | |
289 | rx8581->read_block_data = rx8581_read_block_data; | |
290 | rx8581->write_block_data = rx8581_write_block_data; | |
291 | } | |
a7fa9851 | 292 | |
d643a49a AW |
293 | rx8581->rtc = devm_rtc_device_register(&client->dev, |
294 | rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE); | |
295 | ||
296 | if (IS_ERR(rx8581->rtc)) { | |
297 | dev_err(&client->dev, | |
298 | "unable to register the class device\n"); | |
299 | return PTR_ERR(rx8581->rtc); | |
300 | } | |
a7fa9851 MW |
301 | |
302 | return 0; | |
303 | } | |
304 | ||
a7fa9851 MW |
305 | static const struct i2c_device_id rx8581_id[] = { |
306 | { "rx8581", 0 }, | |
307 | { } | |
308 | }; | |
309 | MODULE_DEVICE_TABLE(i2c, rx8581_id); | |
310 | ||
311 | static struct i2c_driver rx8581_driver = { | |
312 | .driver = { | |
313 | .name = "rtc-rx8581", | |
a7fa9851 MW |
314 | }, |
315 | .probe = rx8581_probe, | |
a7fa9851 MW |
316 | .id_table = rx8581_id, |
317 | }; | |
318 | ||
0abc9201 | 319 | module_i2c_driver(rx8581_driver); |
a7fa9851 | 320 | |
9756c4da | 321 | MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>"); |
a7fa9851 MW |
322 | MODULE_DESCRIPTION("Epson RX-8581 RTC driver"); |
323 | MODULE_LICENSE("GPL"); |