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9c0c5705 L |
1 | /* |
2 | * drivers/rtc/rtc-pcf8583.c | |
3 | * | |
4 | * Copyright (C) 2000 Russell King | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * Driver for PCF8583 RTC & RAM chip | |
11 | * | |
12 | * Converted to the generic RTC susbsystem by G. Liakhovetski (2006) | |
13 | */ | |
14 | #include <linux/module.h> | |
15 | #include <linux/i2c.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/string.h> | |
18 | #include <linux/mc146818rtc.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/errno.h> | |
21 | #include <linux/bcd.h> | |
22 | ||
23 | struct rtc_mem { | |
24 | unsigned int loc; | |
25 | unsigned int nr; | |
26 | unsigned char *data; | |
27 | }; | |
28 | ||
29 | struct pcf8583 { | |
30 | struct i2c_client client; | |
31 | struct rtc_device *rtc; | |
32 | unsigned char ctrl; | |
33 | }; | |
34 | ||
35 | #define CTRL_STOP 0x80 | |
36 | #define CTRL_HOLD 0x40 | |
37 | #define CTRL_32KHZ 0x00 | |
38 | #define CTRL_MASK 0x08 | |
39 | #define CTRL_ALARMEN 0x04 | |
40 | #define CTRL_ALARM 0x02 | |
41 | #define CTRL_TIMER 0x01 | |
42 | ||
bb71f99f | 43 | static unsigned short normal_i2c[] = { 0x50, I2C_CLIENT_END }; |
9c0c5705 L |
44 | |
45 | /* Module parameters */ | |
46 | I2C_CLIENT_INSMOD; | |
47 | ||
48 | static struct i2c_driver pcf8583_driver; | |
49 | ||
50 | #define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl | |
51 | #define set_ctrl(x, v) get_ctrl(x) = v | |
52 | ||
53 | #define CMOS_YEAR (64 + 128) | |
54 | #define CMOS_CHECKSUM (63) | |
55 | ||
56 | static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt) | |
57 | { | |
58 | unsigned char buf[8], addr[1] = { 1 }; | |
59 | struct i2c_msg msgs[2] = { | |
60 | { | |
61 | .addr = client->addr, | |
62 | .flags = 0, | |
63 | .len = 1, | |
64 | .buf = addr, | |
65 | }, { | |
66 | .addr = client->addr, | |
67 | .flags = I2C_M_RD, | |
68 | .len = 6, | |
69 | .buf = buf, | |
70 | } | |
71 | }; | |
72 | int ret; | |
73 | ||
74 | memset(buf, 0, sizeof(buf)); | |
75 | ||
76 | ret = i2c_transfer(client->adapter, msgs, 2); | |
77 | if (ret == 2) { | |
78 | dt->tm_year = buf[4] >> 6; | |
79 | dt->tm_wday = buf[5] >> 5; | |
80 | ||
81 | buf[4] &= 0x3f; | |
82 | buf[5] &= 0x1f; | |
83 | ||
f5e5b734 RK |
84 | dt->tm_sec = BCD2BIN(buf[1]); |
85 | dt->tm_min = BCD2BIN(buf[2]); | |
86 | dt->tm_hour = BCD2BIN(buf[3]); | |
87 | dt->tm_mday = BCD2BIN(buf[4]); | |
0ed8f210 | 88 | dt->tm_mon = BCD2BIN(buf[5]) - 1; |
9c0c5705 L |
89 | } |
90 | ||
91 | return ret == 2 ? 0 : -EIO; | |
92 | } | |
93 | ||
94 | static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo) | |
95 | { | |
96 | unsigned char buf[8]; | |
97 | int ret, len = 6; | |
98 | ||
99 | buf[0] = 0; | |
100 | buf[1] = get_ctrl(client) | 0x80; | |
101 | buf[2] = 0; | |
f5e5b734 RK |
102 | buf[3] = BIN2BCD(dt->tm_sec); |
103 | buf[4] = BIN2BCD(dt->tm_min); | |
104 | buf[5] = BIN2BCD(dt->tm_hour); | |
9c0c5705 L |
105 | |
106 | if (datetoo) { | |
107 | len = 8; | |
f5e5b734 | 108 | buf[6] = BIN2BCD(dt->tm_mday) | (dt->tm_year << 6); |
0ed8f210 | 109 | buf[7] = BIN2BCD(dt->tm_mon + 1) | (dt->tm_wday << 5); |
9c0c5705 L |
110 | } |
111 | ||
112 | ret = i2c_master_send(client, (char *)buf, len); | |
113 | if (ret != len) | |
114 | return -EIO; | |
115 | ||
116 | buf[1] = get_ctrl(client); | |
117 | ret = i2c_master_send(client, (char *)buf, 2); | |
118 | ||
119 | return ret == 2 ? 0 : -EIO; | |
120 | } | |
121 | ||
122 | static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl) | |
123 | { | |
124 | *ctrl = get_ctrl(client); | |
125 | return 0; | |
126 | } | |
127 | ||
128 | static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl) | |
129 | { | |
130 | unsigned char buf[2]; | |
131 | ||
132 | buf[0] = 0; | |
133 | buf[1] = *ctrl; | |
134 | set_ctrl(client, *ctrl); | |
135 | ||
136 | return i2c_master_send(client, (char *)buf, 2); | |
137 | } | |
138 | ||
139 | static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem) | |
140 | { | |
141 | unsigned char addr[1]; | |
142 | struct i2c_msg msgs[2] = { | |
143 | { | |
144 | .addr = client->addr, | |
145 | .flags = 0, | |
146 | .len = 1, | |
147 | .buf = addr, | |
148 | }, { | |
149 | .addr = client->addr, | |
150 | .flags = I2C_M_RD, | |
151 | .len = mem->nr, | |
152 | .buf = mem->data, | |
153 | } | |
154 | }; | |
155 | ||
156 | if (mem->loc < 8) | |
157 | return -EINVAL; | |
158 | ||
159 | addr[0] = mem->loc; | |
160 | ||
161 | return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; | |
162 | } | |
163 | ||
164 | static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem) | |
165 | { | |
166 | unsigned char addr[1]; | |
167 | struct i2c_msg msgs[2] = { | |
168 | { | |
169 | .addr = client->addr, | |
170 | .flags = 0, | |
171 | .len = 1, | |
172 | .buf = addr, | |
173 | }, { | |
174 | .addr = client->addr, | |
175 | .flags = I2C_M_NOSTART, | |
176 | .len = mem->nr, | |
177 | .buf = mem->data, | |
178 | } | |
179 | }; | |
180 | ||
181 | if (mem->loc < 8) | |
182 | return -EINVAL; | |
183 | ||
184 | addr[0] = mem->loc; | |
185 | ||
186 | return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; | |
187 | } | |
188 | ||
189 | static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
190 | { | |
191 | struct i2c_client *client = to_i2c_client(dev); | |
192 | unsigned char ctrl, year[2]; | |
193 | struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year }; | |
194 | int real_year, year_offset, err; | |
195 | ||
196 | /* | |
197 | * Ensure that the RTC is running. | |
198 | */ | |
199 | pcf8583_get_ctrl(client, &ctrl); | |
200 | if (ctrl & (CTRL_STOP | CTRL_HOLD)) { | |
201 | unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD); | |
202 | ||
203 | printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n", | |
204 | ctrl, new_ctrl); | |
205 | ||
206 | if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0) | |
207 | return err; | |
208 | } | |
209 | ||
210 | if (pcf8583_get_datetime(client, tm) || | |
211 | pcf8583_read_mem(client, &mem)) | |
212 | return -EIO; | |
213 | ||
214 | real_year = year[0]; | |
215 | ||
216 | /* | |
217 | * The RTC year holds the LSB two bits of the current | |
218 | * year, which should reflect the LSB two bits of the | |
219 | * CMOS copy of the year. Any difference indicates | |
220 | * that we have to correct the CMOS version. | |
221 | */ | |
222 | year_offset = tm->tm_year - (real_year & 3); | |
223 | if (year_offset < 0) | |
224 | /* | |
225 | * RTC year wrapped. Adjust it appropriately. | |
226 | */ | |
227 | year_offset += 4; | |
228 | ||
0ed8f210 | 229 | tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900; |
9c0c5705 L |
230 | |
231 | return 0; | |
232 | } | |
233 | ||
234 | static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
235 | { | |
236 | struct i2c_client *client = to_i2c_client(dev); | |
237 | unsigned char year[2], chk; | |
238 | struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year }; | |
239 | struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk }; | |
0ed8f210 | 240 | unsigned int proper_year = tm->tm_year + 1900; |
9c0c5705 L |
241 | int ret; |
242 | ||
243 | /* | |
244 | * The RTC's own 2-bit year must reflect the least | |
245 | * significant two bits of the CMOS year. | |
246 | */ | |
247 | ||
248 | ret = pcf8583_set_datetime(client, tm, 1); | |
249 | if (ret) | |
250 | return ret; | |
251 | ||
252 | ret = pcf8583_read_mem(client, &cmos_check); | |
253 | if (ret) | |
254 | return ret; | |
255 | ||
256 | ret = pcf8583_read_mem(client, &cmos_year); | |
257 | if (ret) | |
258 | return ret; | |
259 | ||
260 | chk -= year[1] + year[0]; | |
261 | ||
0ed8f210 RK |
262 | year[1] = proper_year / 100; |
263 | year[0] = proper_year % 100; | |
9c0c5705 L |
264 | |
265 | chk += year[1] + year[0]; | |
266 | ||
267 | ret = pcf8583_write_mem(client, &cmos_year); | |
268 | ||
269 | if (ret) | |
270 | return ret; | |
271 | ||
272 | ret = pcf8583_write_mem(client, &cmos_check); | |
273 | ||
274 | return ret; | |
275 | } | |
276 | ||
ff8371ac | 277 | static const struct rtc_class_ops pcf8583_rtc_ops = { |
9c0c5705 L |
278 | .read_time = pcf8583_rtc_read_time, |
279 | .set_time = pcf8583_rtc_set_time, | |
280 | }; | |
281 | ||
282 | static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind); | |
283 | ||
284 | static int pcf8583_attach(struct i2c_adapter *adap) | |
285 | { | |
286 | return i2c_probe(adap, &addr_data, pcf8583_probe); | |
287 | } | |
288 | ||
289 | static int pcf8583_detach(struct i2c_client *client) | |
290 | { | |
291 | int err; | |
292 | struct pcf8583 *pcf = i2c_get_clientdata(client); | |
293 | struct rtc_device *rtc = pcf->rtc; | |
294 | ||
295 | if (rtc) | |
296 | rtc_device_unregister(rtc); | |
297 | ||
298 | if ((err = i2c_detach_client(client))) | |
299 | return err; | |
300 | ||
301 | kfree(pcf); | |
302 | return 0; | |
303 | } | |
304 | ||
305 | static struct i2c_driver pcf8583_driver = { | |
306 | .driver = { | |
307 | .name = "pcf8583", | |
308 | }, | |
309 | .id = I2C_DRIVERID_PCF8583, | |
310 | .attach_adapter = pcf8583_attach, | |
311 | .detach_client = pcf8583_detach, | |
312 | }; | |
313 | ||
314 | static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind) | |
315 | { | |
316 | struct pcf8583 *pcf; | |
317 | struct i2c_client *client; | |
318 | struct rtc_device *rtc; | |
319 | unsigned char buf[1], ad[1] = { 0 }; | |
320 | int err; | |
321 | struct i2c_msg msgs[2] = { | |
322 | { | |
323 | .addr = addr, | |
324 | .flags = 0, | |
325 | .len = 1, | |
326 | .buf = ad, | |
327 | }, { | |
328 | .addr = addr, | |
329 | .flags = I2C_M_RD, | |
330 | .len = 1, | |
331 | .buf = buf, | |
332 | } | |
333 | }; | |
334 | ||
335 | pcf = kzalloc(sizeof(*pcf), GFP_KERNEL); | |
336 | if (!pcf) | |
337 | return -ENOMEM; | |
338 | ||
339 | client = &pcf->client; | |
340 | ||
341 | client->addr = addr; | |
342 | client->adapter = adap; | |
343 | client->driver = &pcf8583_driver; | |
344 | ||
345 | strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE); | |
346 | ||
347 | if (i2c_transfer(client->adapter, msgs, 2) != 2) { | |
348 | err = -EIO; | |
349 | goto exit_kfree; | |
350 | } | |
351 | ||
352 | err = i2c_attach_client(client); | |
353 | ||
354 | if (err) | |
355 | goto exit_kfree; | |
356 | ||
357 | rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev, | |
358 | &pcf8583_rtc_ops, THIS_MODULE); | |
359 | ||
360 | if (IS_ERR(rtc)) { | |
361 | err = PTR_ERR(rtc); | |
362 | goto exit_detach; | |
363 | } | |
364 | ||
365 | pcf->rtc = rtc; | |
366 | i2c_set_clientdata(client, pcf); | |
367 | set_ctrl(client, buf[0]); | |
368 | ||
369 | return 0; | |
370 | ||
371 | exit_detach: | |
372 | i2c_detach_client(client); | |
373 | ||
374 | exit_kfree: | |
375 | kfree(pcf); | |
376 | ||
377 | return err; | |
378 | } | |
379 | ||
380 | static __init int pcf8583_init(void) | |
381 | { | |
382 | return i2c_add_driver(&pcf8583_driver); | |
383 | } | |
384 | ||
385 | static __exit void pcf8583_exit(void) | |
386 | { | |
387 | i2c_del_driver(&pcf8583_driver); | |
388 | } | |
389 | ||
390 | module_init(pcf8583_init); | |
391 | module_exit(pcf8583_exit); | |
392 | ||
393 | MODULE_AUTHOR("Russell King"); | |
394 | MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); | |
395 | MODULE_LICENSE("GPL"); |