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1 | /* |
2 | * Seiko Instruments S-35390A RTC Driver | |
3 | * | |
4 | * Copyright (c) 2007 Byron Bradley | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/rtc.h> | |
14 | #include <linux/i2c.h> | |
15 | #include <linux/bitrev.h> | |
16 | #include <linux/bcd.h> | |
17 | #include <linux/slab.h> | |
18 | ||
19 | #define S35390A_CMD_STATUS1 0 | |
20 | #define S35390A_CMD_STATUS2 1 | |
21 | #define S35390A_CMD_TIME1 2 | |
22 | ||
23 | #define S35390A_BYTE_YEAR 0 | |
24 | #define S35390A_BYTE_MONTH 1 | |
25 | #define S35390A_BYTE_DAY 2 | |
26 | #define S35390A_BYTE_WDAY 3 | |
27 | #define S35390A_BYTE_HOURS 4 | |
28 | #define S35390A_BYTE_MINS 5 | |
29 | #define S35390A_BYTE_SECS 6 | |
30 | ||
31 | #define S35390A_FLAG_POC 0x01 | |
32 | #define S35390A_FLAG_BLD 0x02 | |
33 | #define S35390A_FLAG_24H 0x40 | |
34 | #define S35390A_FLAG_RESET 0x80 | |
35 | #define S35390A_FLAG_TEST 0x01 | |
36 | ||
37 | struct s35390a { | |
38 | struct i2c_client *client[8]; | |
39 | struct rtc_device *rtc; | |
40 | int twentyfourhour; | |
41 | }; | |
42 | ||
43 | static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len) | |
44 | { | |
45 | struct i2c_client *client = s35390a->client[reg]; | |
46 | struct i2c_msg msg[] = { | |
47 | { client->addr, 0, len, buf }, | |
48 | }; | |
49 | ||
50 | if ((i2c_transfer(client->adapter, msg, 1)) != 1) | |
51 | return -EIO; | |
52 | ||
53 | return 0; | |
54 | } | |
55 | ||
56 | static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len) | |
57 | { | |
58 | struct i2c_client *client = s35390a->client[reg]; | |
59 | struct i2c_msg msg[] = { | |
60 | { client->addr, I2C_M_RD, len, buf }, | |
61 | }; | |
62 | ||
63 | if ((i2c_transfer(client->adapter, msg, 1)) != 1) | |
64 | return -EIO; | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
69 | static int s35390a_reset(struct s35390a *s35390a) | |
70 | { | |
71 | char buf[1]; | |
72 | ||
73 | if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0) | |
74 | return -EIO; | |
75 | ||
76 | if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD))) | |
77 | return 0; | |
78 | ||
79 | buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H); | |
80 | buf[0] &= 0xf0; | |
81 | return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)); | |
82 | } | |
83 | ||
84 | static int s35390a_disable_test_mode(struct s35390a *s35390a) | |
85 | { | |
86 | char buf[1]; | |
87 | ||
88 | if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0) | |
89 | return -EIO; | |
90 | ||
91 | if (!(buf[0] & S35390A_FLAG_TEST)) | |
92 | return 0; | |
93 | ||
94 | buf[0] &= ~S35390A_FLAG_TEST; | |
95 | return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)); | |
96 | } | |
97 | ||
98 | static char s35390a_hr2reg(struct s35390a *s35390a, int hour) | |
99 | { | |
100 | if (s35390a->twentyfourhour) | |
101 | return BIN2BCD(hour); | |
102 | ||
103 | if (hour < 12) | |
104 | return BIN2BCD(hour); | |
105 | ||
106 | return 0x40 | BIN2BCD(hour - 12); | |
107 | } | |
108 | ||
109 | static int s35390a_reg2hr(struct s35390a *s35390a, char reg) | |
110 | { | |
111 | unsigned hour; | |
112 | ||
113 | if (s35390a->twentyfourhour) | |
114 | return BCD2BIN(reg & 0x3f); | |
115 | ||
116 | hour = BCD2BIN(reg & 0x3f); | |
117 | if (reg & 0x40) | |
118 | hour += 12; | |
119 | ||
120 | return hour; | |
121 | } | |
122 | ||
123 | static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm) | |
124 | { | |
125 | struct s35390a *s35390a = i2c_get_clientdata(client); | |
126 | int i, err; | |
127 | char buf[7]; | |
128 | ||
129 | dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, " | |
130 | "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, | |
131 | tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, | |
132 | tm->tm_wday); | |
133 | ||
134 | buf[S35390A_BYTE_YEAR] = BIN2BCD(tm->tm_year - 100); | |
135 | buf[S35390A_BYTE_MONTH] = BIN2BCD(tm->tm_mon + 1); | |
136 | buf[S35390A_BYTE_DAY] = BIN2BCD(tm->tm_mday); | |
137 | buf[S35390A_BYTE_WDAY] = BIN2BCD(tm->tm_wday); | |
138 | buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour); | |
139 | buf[S35390A_BYTE_MINS] = BIN2BCD(tm->tm_min); | |
140 | buf[S35390A_BYTE_SECS] = BIN2BCD(tm->tm_sec); | |
141 | ||
142 | /* This chip expects the bits of each byte to be in reverse order */ | |
143 | for (i = 0; i < 7; ++i) | |
144 | buf[i] = bitrev8(buf[i]); | |
145 | ||
146 | err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); | |
147 | ||
148 | return err; | |
149 | } | |
150 | ||
151 | static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm) | |
152 | { | |
153 | struct s35390a *s35390a = i2c_get_clientdata(client); | |
154 | char buf[7]; | |
155 | int i, err; | |
156 | ||
157 | err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); | |
158 | if (err < 0) | |
159 | return err; | |
160 | ||
161 | /* This chip returns the bits of each byte in reverse order */ | |
162 | for (i = 0; i < 7; ++i) | |
163 | buf[i] = bitrev8(buf[i]); | |
164 | ||
165 | tm->tm_sec = BCD2BIN(buf[S35390A_BYTE_SECS]); | |
166 | tm->tm_min = BCD2BIN(buf[S35390A_BYTE_MINS]); | |
167 | tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]); | |
168 | tm->tm_wday = BCD2BIN(buf[S35390A_BYTE_WDAY]); | |
169 | tm->tm_mday = BCD2BIN(buf[S35390A_BYTE_DAY]); | |
170 | tm->tm_mon = BCD2BIN(buf[S35390A_BYTE_MONTH]) - 1; | |
171 | tm->tm_year = BCD2BIN(buf[S35390A_BYTE_YEAR]) + 100; | |
172 | ||
173 | dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, " | |
174 | "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, | |
175 | tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, | |
176 | tm->tm_wday); | |
177 | ||
178 | return rtc_valid_tm(tm); | |
179 | } | |
180 | ||
181 | static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
182 | { | |
183 | return s35390a_get_datetime(to_i2c_client(dev), tm); | |
184 | } | |
185 | ||
186 | static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
187 | { | |
188 | return s35390a_set_datetime(to_i2c_client(dev), tm); | |
189 | } | |
190 | ||
191 | static const struct rtc_class_ops s35390a_rtc_ops = { | |
192 | .read_time = s35390a_rtc_read_time, | |
193 | .set_time = s35390a_rtc_set_time, | |
194 | }; | |
195 | ||
196 | static struct i2c_driver s35390a_driver; | |
197 | ||
198 | static int s35390a_probe(struct i2c_client *client) | |
199 | { | |
200 | int err; | |
201 | unsigned int i; | |
202 | struct s35390a *s35390a; | |
203 | struct rtc_time tm; | |
204 | char buf[1]; | |
205 | ||
206 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { | |
207 | err = -ENODEV; | |
208 | goto exit; | |
209 | } | |
210 | ||
211 | s35390a = kzalloc(sizeof(struct s35390a), GFP_KERNEL); | |
212 | if (!s35390a) { | |
213 | err = -ENOMEM; | |
214 | goto exit; | |
215 | } | |
216 | ||
217 | s35390a->client[0] = client; | |
218 | i2c_set_clientdata(client, s35390a); | |
219 | ||
220 | /* This chip uses multiple addresses, use dummy devices for them */ | |
221 | for (i = 1; i < 8; ++i) { | |
222 | s35390a->client[i] = i2c_new_dummy(client->adapter, | |
223 | client->addr + i, "rtc-s35390a"); | |
224 | if (!s35390a->client[i]) { | |
225 | dev_err(&client->dev, "Address %02x unavailable\n", | |
226 | client->addr + i); | |
227 | err = -EBUSY; | |
228 | goto exit_dummy; | |
229 | } | |
230 | } | |
231 | ||
232 | err = s35390a_reset(s35390a); | |
233 | if (err < 0) { | |
234 | dev_err(&client->dev, "error resetting chip\n"); | |
235 | goto exit_dummy; | |
236 | } | |
237 | ||
238 | err = s35390a_disable_test_mode(s35390a); | |
239 | if (err < 0) { | |
240 | dev_err(&client->dev, "error disabling test mode\n"); | |
241 | goto exit_dummy; | |
242 | } | |
243 | ||
244 | err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)); | |
245 | if (err < 0) { | |
246 | dev_err(&client->dev, "error checking 12/24 hour mode\n"); | |
247 | goto exit_dummy; | |
248 | } | |
249 | if (buf[0] & S35390A_FLAG_24H) | |
250 | s35390a->twentyfourhour = 1; | |
251 | else | |
252 | s35390a->twentyfourhour = 0; | |
253 | ||
254 | if (s35390a_get_datetime(client, &tm) < 0) | |
255 | dev_warn(&client->dev, "clock needs to be set\n"); | |
256 | ||
257 | s35390a->rtc = rtc_device_register(s35390a_driver.driver.name, | |
258 | &client->dev, &s35390a_rtc_ops, THIS_MODULE); | |
259 | ||
260 | if (IS_ERR(s35390a->rtc)) { | |
261 | err = PTR_ERR(s35390a->rtc); | |
262 | goto exit_dummy; | |
263 | } | |
264 | return 0; | |
265 | ||
266 | exit_dummy: | |
267 | for (i = 1; i < 8; ++i) | |
268 | if (s35390a->client[i]) | |
269 | i2c_unregister_device(s35390a->client[i]); | |
270 | kfree(s35390a); | |
271 | i2c_set_clientdata(client, NULL); | |
272 | ||
273 | exit: | |
274 | return err; | |
275 | } | |
276 | ||
277 | static int s35390a_remove(struct i2c_client *client) | |
278 | { | |
279 | unsigned int i; | |
280 | ||
281 | struct s35390a *s35390a = i2c_get_clientdata(client); | |
282 | for (i = 1; i < 8; ++i) | |
283 | if (s35390a->client[i]) | |
284 | i2c_unregister_device(s35390a->client[i]); | |
285 | ||
286 | rtc_device_unregister(s35390a->rtc); | |
287 | kfree(s35390a); | |
288 | i2c_set_clientdata(client, NULL); | |
289 | ||
290 | return 0; | |
291 | } | |
292 | ||
293 | static struct i2c_driver s35390a_driver = { | |
294 | .driver = { | |
295 | .name = "rtc-s35390a", | |
296 | }, | |
297 | .probe = s35390a_probe, | |
298 | .remove = s35390a_remove, | |
299 | }; | |
300 | ||
301 | static int __init s35390a_rtc_init(void) | |
302 | { | |
303 | return i2c_add_driver(&s35390a_driver); | |
304 | } | |
305 | ||
306 | static void __exit s35390a_rtc_exit(void) | |
307 | { | |
308 | i2c_del_driver(&s35390a_driver); | |
309 | } | |
310 | ||
311 | MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>"); | |
312 | MODULE_DESCRIPTION("S35390A RTC driver"); | |
313 | MODULE_LICENSE("GPL"); | |
314 | ||
315 | module_init(s35390a_rtc_init); | |
316 | module_exit(s35390a_rtc_exit); |