Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6/linux-2.6-openrd.git] / drivers / rtc / rtc-pcf8563.c
blob65f346b2fbaebfcf73b58759e6622d6e9ababefd
1 /*
2 * An I2C driver for the Philips PCF8563 RTC
3 * Copyright 2005-06 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
6 * Maintainers: http://www.nslu2-linux.org/
8 * based on the other drivers in this same directory.
10 * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
17 #include <linux/i2c.h>
18 #include <linux/bcd.h>
19 #include <linux/rtc.h>
21 #define DRV_VERSION "0.4.3"
23 #define PCF8563_REG_ST1 0x00 /* status */
24 #define PCF8563_REG_ST2 0x01
26 #define PCF8563_REG_SC 0x02 /* datetime */
27 #define PCF8563_REG_MN 0x03
28 #define PCF8563_REG_HR 0x04
29 #define PCF8563_REG_DM 0x05
30 #define PCF8563_REG_DW 0x06
31 #define PCF8563_REG_MO 0x07
32 #define PCF8563_REG_YR 0x08
34 #define PCF8563_REG_AMN 0x09 /* alarm */
35 #define PCF8563_REG_AHR 0x0A
36 #define PCF8563_REG_ADM 0x0B
37 #define PCF8563_REG_ADW 0x0C
39 #define PCF8563_REG_CLKO 0x0D /* clock out */
40 #define PCF8563_REG_TMRC 0x0E /* timer control */
41 #define PCF8563_REG_TMR 0x0F /* timer */
43 #define PCF8563_SC_LV 0x80 /* low voltage */
44 #define PCF8563_MO_C 0x80 /* century */
46 static struct i2c_driver pcf8563_driver;
48 struct pcf8563 {
49 struct rtc_device *rtc;
51 * The meaning of MO_C bit varies by the chip type.
52 * From PCF8563 datasheet: this bit is toggled when the years
53 * register overflows from 99 to 00
54 * 0 indicates the century is 20xx
55 * 1 indicates the century is 19xx
56 * From RTC8564 datasheet: this bit indicates change of
57 * century. When the year digit data overflows from 99 to 00,
58 * this bit is set. By presetting it to 0 while still in the
59 * 20th century, it will be set in year 2000, ...
60 * There seems no reliable way to know how the system use this
61 * bit. So let's do it heuristically, assuming we are live in
62 * 1970...2069.
64 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
68 * In the routines that deal directly with the pcf8563 hardware, we use
69 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
71 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
73 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
74 unsigned char buf[13] = { PCF8563_REG_ST1 };
76 struct i2c_msg msgs[] = {
77 { client->addr, 0, 1, buf }, /* setup read ptr */
78 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */
81 /* read registers */
82 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
83 dev_err(&client->dev, "%s: read error\n", __func__);
84 return -EIO;
87 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
88 dev_info(&client->dev,
89 "low voltage detected, date/time is not reliable.\n");
91 dev_dbg(&client->dev,
92 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
93 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
94 __func__,
95 buf[0], buf[1], buf[2], buf[3],
96 buf[4], buf[5], buf[6], buf[7],
97 buf[8]);
100 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
101 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
102 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
103 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
104 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
105 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
106 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
107 if (tm->tm_year < 70)
108 tm->tm_year += 100; /* assume we are in 1970...2069 */
109 /* detect the polarity heuristically. see note above. */
110 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
111 (tm->tm_year >= 100) : (tm->tm_year < 100);
113 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
114 "mday=%d, mon=%d, year=%d, wday=%d\n",
115 __func__,
116 tm->tm_sec, tm->tm_min, tm->tm_hour,
117 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
119 /* the clock can give out invalid datetime, but we cannot return
120 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
122 if (rtc_valid_tm(tm) < 0)
123 dev_err(&client->dev, "retrieved date/time is not valid.\n");
125 return 0;
128 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
130 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
131 int i, err;
132 unsigned char buf[9];
134 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
135 "mday=%d, mon=%d, year=%d, wday=%d\n",
136 __func__,
137 tm->tm_sec, tm->tm_min, tm->tm_hour,
138 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
140 /* hours, minutes and seconds */
141 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
142 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
143 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
145 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
147 /* month, 1 - 12 */
148 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
150 /* year and century */
151 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
152 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
153 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
155 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
157 /* write register's data */
158 for (i = 0; i < 7; i++) {
159 unsigned char data[2] = { PCF8563_REG_SC + i,
160 buf[PCF8563_REG_SC + i] };
162 err = i2c_master_send(client, data, sizeof(data));
163 if (err != sizeof(data)) {
164 dev_err(&client->dev,
165 "%s: err=%d addr=%02x, data=%02x\n",
166 __func__, err, data[0], data[1]);
167 return -EIO;
171 return 0;
174 struct pcf8563_limit
176 unsigned char reg;
177 unsigned char mask;
178 unsigned char min;
179 unsigned char max;
182 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
184 return pcf8563_get_datetime(to_i2c_client(dev), tm);
187 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
189 return pcf8563_set_datetime(to_i2c_client(dev), tm);
192 static const struct rtc_class_ops pcf8563_rtc_ops = {
193 .read_time = pcf8563_rtc_read_time,
194 .set_time = pcf8563_rtc_set_time,
197 static int pcf8563_probe(struct i2c_client *client,
198 const struct i2c_device_id *id)
200 struct pcf8563 *pcf8563;
202 int err = 0;
204 dev_dbg(&client->dev, "%s\n", __func__);
206 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
207 return -ENODEV;
209 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
210 if (!pcf8563)
211 return -ENOMEM;
213 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
215 i2c_set_clientdata(client, pcf8563);
217 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
218 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
220 if (IS_ERR(pcf8563->rtc)) {
221 err = PTR_ERR(pcf8563->rtc);
222 goto exit_kfree;
225 return 0;
227 exit_kfree:
228 kfree(pcf8563);
230 return err;
233 static int pcf8563_remove(struct i2c_client *client)
235 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
237 if (pcf8563->rtc)
238 rtc_device_unregister(pcf8563->rtc);
240 kfree(pcf8563);
242 return 0;
245 static const struct i2c_device_id pcf8563_id[] = {
246 { "pcf8563", 0 },
247 { "rtc8564", 0 },
250 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
252 static struct i2c_driver pcf8563_driver = {
253 .driver = {
254 .name = "rtc-pcf8563",
256 .probe = pcf8563_probe,
257 .remove = pcf8563_remove,
258 .id_table = pcf8563_id,
261 static int __init pcf8563_init(void)
263 return i2c_add_driver(&pcf8563_driver);
266 static void __exit pcf8563_exit(void)
268 i2c_del_driver(&pcf8563_driver);
271 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
272 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
273 MODULE_LICENSE("GPL");
274 MODULE_VERSION(DRV_VERSION);
276 module_init(pcf8563_init);
277 module_exit(pcf8563_exit);