blob: 3d09d8f0b1f0244220bcd1562d109664fa87f266 [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>
David Brownell77459b02008-04-28 02:11:51 -070018#include <linux/rtc.h>
G. Liakhovetski9c0c5702006-06-25 05:48:18 -070019#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
Jean Delvare922539a2008-01-27 18:14:47 +010043static const unsigned short normal_i2c[] = { 0x50, I2C_CLIENT_END };
G. Liakhovetski9c0c5702006-06-25 05:48:18 -070044
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
Russell Kingf5e5b732007-03-04 20:12:07 +000084 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]);
Russell King0ed8f212007-03-04 20:13:13 +000088 dt->tm_mon = BCD2BIN(buf[5]) - 1;
G. Liakhovetski9c0c5702006-06-25 05:48:18 -070089 }
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;
Russell Kingf5e5b732007-03-04 20:12:07 +0000102 buf[3] = BIN2BCD(dt->tm_sec);
103 buf[4] = BIN2BCD(dt->tm_min);
104 buf[5] = BIN2BCD(dt->tm_hour);
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700105
106 if (datetoo) {
107 len = 8;
Russell Kingf5e5b732007-03-04 20:12:07 +0000108 buf[6] = BIN2BCD(dt->tm_mday) | (dt->tm_year << 6);
Russell King0ed8f212007-03-04 20:13:13 +0000109 buf[7] = BIN2BCD(dt->tm_mon + 1) | (dt->tm_wday << 5);
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700110 }
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{
Jean Delvare037e2912008-02-06 01:38:41 -0800166 unsigned char buf[9];
167 int ret;
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700168
Jean Delvare037e2912008-02-06 01:38:41 -0800169 if (mem->loc < 8 || mem->nr > 8)
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700170 return -EINVAL;
171
Jean Delvare037e2912008-02-06 01:38:41 -0800172 buf[0] = mem->loc;
173 memcpy(buf + 1, mem->data, mem->nr);
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700174
Jean Delvare037e2912008-02-06 01:38:41 -0800175 ret = i2c_master_send(client, buf, mem->nr + 1);
176 return ret == mem->nr + 1 ? 0 : -EIO;
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700177}
178
179static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm)
180{
181 struct i2c_client *client = to_i2c_client(dev);
182 unsigned char ctrl, year[2];
183 struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year };
184 int real_year, year_offset, err;
185
186 /*
187 * Ensure that the RTC is running.
188 */
189 pcf8583_get_ctrl(client, &ctrl);
190 if (ctrl & (CTRL_STOP | CTRL_HOLD)) {
191 unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD);
192
193 printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n",
194 ctrl, new_ctrl);
195
196 if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0)
197 return err;
198 }
199
200 if (pcf8583_get_datetime(client, tm) ||
201 pcf8583_read_mem(client, &mem))
202 return -EIO;
203
204 real_year = year[0];
205
206 /*
207 * The RTC year holds the LSB two bits of the current
208 * year, which should reflect the LSB two bits of the
209 * CMOS copy of the year. Any difference indicates
210 * that we have to correct the CMOS version.
211 */
212 year_offset = tm->tm_year - (real_year & 3);
213 if (year_offset < 0)
214 /*
215 * RTC year wrapped. Adjust it appropriately.
216 */
217 year_offset += 4;
218
Russell King0ed8f212007-03-04 20:13:13 +0000219 tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700220
221 return 0;
222}
223
224static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm)
225{
226 struct i2c_client *client = to_i2c_client(dev);
227 unsigned char year[2], chk;
228 struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year };
229 struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk };
Russell King0ed8f212007-03-04 20:13:13 +0000230 unsigned int proper_year = tm->tm_year + 1900;
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700231 int ret;
232
233 /*
234 * The RTC's own 2-bit year must reflect the least
235 * significant two bits of the CMOS year.
236 */
237
238 ret = pcf8583_set_datetime(client, tm, 1);
239 if (ret)
240 return ret;
241
242 ret = pcf8583_read_mem(client, &cmos_check);
243 if (ret)
244 return ret;
245
246 ret = pcf8583_read_mem(client, &cmos_year);
247 if (ret)
248 return ret;
249
250 chk -= year[1] + year[0];
251
Russell King0ed8f212007-03-04 20:13:13 +0000252 year[1] = proper_year / 100;
253 year[0] = proper_year % 100;
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700254
255 chk += year[1] + year[0];
256
257 ret = pcf8583_write_mem(client, &cmos_year);
258
259 if (ret)
260 return ret;
261
262 ret = pcf8583_write_mem(client, &cmos_check);
263
264 return ret;
265}
266
David Brownellff8371a2006-09-30 23:28:17 -0700267static const struct rtc_class_ops pcf8583_rtc_ops = {
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700268 .read_time = pcf8583_rtc_read_time,
269 .set_time = pcf8583_rtc_set_time,
270};
271
272static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind);
273
274static int pcf8583_attach(struct i2c_adapter *adap)
275{
276 return i2c_probe(adap, &addr_data, pcf8583_probe);
277}
278
279static int pcf8583_detach(struct i2c_client *client)
280{
281 int err;
282 struct pcf8583 *pcf = i2c_get_clientdata(client);
283 struct rtc_device *rtc = pcf->rtc;
284
285 if (rtc)
286 rtc_device_unregister(rtc);
287
288 if ((err = i2c_detach_client(client)))
289 return err;
290
291 kfree(pcf);
292 return 0;
293}
294
295static struct i2c_driver pcf8583_driver = {
296 .driver = {
297 .name = "pcf8583",
298 },
299 .id = I2C_DRIVERID_PCF8583,
300 .attach_adapter = pcf8583_attach,
301 .detach_client = pcf8583_detach,
302};
303
304static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind)
305{
306 struct pcf8583 *pcf;
307 struct i2c_client *client;
308 struct rtc_device *rtc;
309 unsigned char buf[1], ad[1] = { 0 };
310 int err;
311 struct i2c_msg msgs[2] = {
312 {
313 .addr = addr,
314 .flags = 0,
315 .len = 1,
316 .buf = ad,
317 }, {
318 .addr = addr,
319 .flags = I2C_M_RD,
320 .len = 1,
321 .buf = buf,
322 }
323 };
324
Jean Delvarec0186642007-10-16 01:28:18 -0700325 if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
326 return 0;
327
G. Liakhovetski9c0c5702006-06-25 05:48:18 -0700328 pcf = kzalloc(sizeof(*pcf), GFP_KERNEL);
329 if (!pcf)
330 return -ENOMEM;
331
332 client = &pcf->client;
333
334 client->addr = addr;
335 client->adapter = adap;
336 client->driver = &pcf8583_driver;
337
338 strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE);
339
340 if (i2c_transfer(client->adapter, msgs, 2) != 2) {
341 err = -EIO;
342 goto exit_kfree;
343 }
344
345 err = i2c_attach_client(client);
346
347 if (err)
348 goto exit_kfree;
349
350 rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev,
351 &pcf8583_rtc_ops, THIS_MODULE);
352
353 if (IS_ERR(rtc)) {
354 err = PTR_ERR(rtc);
355 goto exit_detach;
356 }
357
358 pcf->rtc = rtc;
359 i2c_set_clientdata(client, pcf);
360 set_ctrl(client, buf[0]);
361
362 return 0;
363
364exit_detach:
365 i2c_detach_client(client);
366
367exit_kfree:
368 kfree(pcf);
369
370 return err;
371}
372
373static __init int pcf8583_init(void)
374{
375 return i2c_add_driver(&pcf8583_driver);
376}
377
378static __exit void pcf8583_exit(void)
379{
380 i2c_del_driver(&pcf8583_driver);
381}
382
383module_init(pcf8583_init);
384module_exit(pcf8583_exit);
385
386MODULE_AUTHOR("Russell King");
387MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
388MODULE_LICENSE("GPL");