blob: 5875ebb8c79d9c3070c025860a8a5b1cf428fbec [file] [log] [blame]
G. Liakhovetski9c0c5702006-06-25 05:48:18 -07001/*
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
23struct rtc_mem {
24 unsigned int loc;
25 unsigned int nr;
26 unsigned char *data;
27};
28
29struct 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
43static unsigned short normal_i2c[] = { I2C_CLIENT_END };
44
45/* Module parameters */
46I2C_CLIENT_INSMOD;
47
48static 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
56static 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
84 dt->tm_sec = BCD_TO_BIN(buf[1]);
85 dt->tm_min = BCD_TO_BIN(buf[2]);
86 dt->tm_hour = BCD_TO_BIN(buf[3]);
87 dt->tm_mday = BCD_TO_BIN(buf[4]);
88 dt->tm_mon = BCD_TO_BIN(buf[5]);
89 }
90
91 return ret == 2 ? 0 : -EIO;
92}
93
94static 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;
102 buf[3] = BIN_TO_BCD(dt->tm_sec);
103 buf[4] = BIN_TO_BCD(dt->tm_min);
104 buf[5] = BIN_TO_BCD(dt->tm_hour);
105
106 if (datetoo) {
107 len = 8;
108 buf[6] = BIN_TO_BCD(dt->tm_mday) | (dt->tm_year << 6);
109 buf[7] = BIN_TO_BCD(dt->tm_mon) | (dt->tm_wday << 5);
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
122static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
123{
124 *ctrl = get_ctrl(client);
125 return 0;
126}
127
128static 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
139static 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
164static 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
189static 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
229 tm->tm_year = real_year + year_offset + year[1] * 100;
230
231 return 0;
232}
233
234static 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 };
240 int ret;
241
242 /*
243 * The RTC's own 2-bit year must reflect the least
244 * significant two bits of the CMOS year.
245 */
246
247 ret = pcf8583_set_datetime(client, tm, 1);
248 if (ret)
249 return ret;
250
251 ret = pcf8583_read_mem(client, &cmos_check);
252 if (ret)
253 return ret;
254
255 ret = pcf8583_read_mem(client, &cmos_year);
256 if (ret)
257 return ret;
258
259 chk -= year[1] + year[0];
260
261 year[1] = tm->tm_year / 100;
262 year[0] = tm->tm_year % 100;
263
264 chk += year[1] + year[0];
265
266 ret = pcf8583_write_mem(client, &cmos_year);
267
268 if (ret)
269 return ret;
270
271 ret = pcf8583_write_mem(client, &cmos_check);
272
273 return ret;
274}
275
David Brownellff8371a2006-09-30 23:28:17 -0700276static const struct rtc_class_ops pcf8583_rtc_ops = {
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700277 .read_time = pcf8583_rtc_read_time,
278 .set_time = pcf8583_rtc_set_time,
279};
280
281static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind);
282
283static int pcf8583_attach(struct i2c_adapter *adap)
284{
285 return i2c_probe(adap, &addr_data, pcf8583_probe);
286}
287
288static int pcf8583_detach(struct i2c_client *client)
289{
290 int err;
291 struct pcf8583 *pcf = i2c_get_clientdata(client);
292 struct rtc_device *rtc = pcf->rtc;
293
294 if (rtc)
295 rtc_device_unregister(rtc);
296
297 if ((err = i2c_detach_client(client)))
298 return err;
299
300 kfree(pcf);
301 return 0;
302}
303
304static struct i2c_driver pcf8583_driver = {
305 .driver = {
306 .name = "pcf8583",
307 },
308 .id = I2C_DRIVERID_PCF8583,
309 .attach_adapter = pcf8583_attach,
310 .detach_client = pcf8583_detach,
311};
312
313static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind)
314{
315 struct pcf8583 *pcf;
316 struct i2c_client *client;
317 struct rtc_device *rtc;
318 unsigned char buf[1], ad[1] = { 0 };
319 int err;
320 struct i2c_msg msgs[2] = {
321 {
322 .addr = addr,
323 .flags = 0,
324 .len = 1,
325 .buf = ad,
326 }, {
327 .addr = addr,
328 .flags = I2C_M_RD,
329 .len = 1,
330 .buf = buf,
331 }
332 };
333
334 pcf = kzalloc(sizeof(*pcf), GFP_KERNEL);
335 if (!pcf)
336 return -ENOMEM;
337
338 client = &pcf->client;
339
340 client->addr = addr;
341 client->adapter = adap;
342 client->driver = &pcf8583_driver;
343
344 strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE);
345
346 if (i2c_transfer(client->adapter, msgs, 2) != 2) {
347 err = -EIO;
348 goto exit_kfree;
349 }
350
351 err = i2c_attach_client(client);
352
353 if (err)
354 goto exit_kfree;
355
356 rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev,
357 &pcf8583_rtc_ops, THIS_MODULE);
358
359 if (IS_ERR(rtc)) {
360 err = PTR_ERR(rtc);
361 goto exit_detach;
362 }
363
364 pcf->rtc = rtc;
365 i2c_set_clientdata(client, pcf);
366 set_ctrl(client, buf[0]);
367
368 return 0;
369
370exit_detach:
371 i2c_detach_client(client);
372
373exit_kfree:
374 kfree(pcf);
375
376 return err;
377}
378
379static __init int pcf8583_init(void)
380{
381 return i2c_add_driver(&pcf8583_driver);
382}
383
384static __exit void pcf8583_exit(void)
385{
386 i2c_del_driver(&pcf8583_driver);
387}
388
389module_init(pcf8583_init);
390module_exit(pcf8583_exit);
391
392MODULE_AUTHOR("Russell King");
393MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
394MODULE_LICENSE("GPL");