Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / drivers / rtc / rtc-pcf8563.c
blobb42c0c6792667cb163d397e6f10ab8eced5f4999
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>
20 #include <linux/slab.h>
22 #define DRV_VERSION "0.4.3"
24 #define PCF8563_REG_ST1 0x00 /* status */
25 #define PCF8563_REG_ST2 0x01
27 #define PCF8563_REG_SC 0x02 /* datetime */
28 #define PCF8563_REG_MN 0x03
29 #define PCF8563_REG_HR 0x04
30 #define PCF8563_REG_DM 0x05
31 #define PCF8563_REG_DW 0x06
32 #define PCF8563_REG_MO 0x07
33 #define PCF8563_REG_YR 0x08
35 #define PCF8563_REG_AMN 0x09 /* alarm */
36 #define PCF8563_REG_AHR 0x0A
37 #define PCF8563_REG_ADM 0x0B
38 #define PCF8563_REG_ADW 0x0C
40 #define PCF8563_REG_CLKO 0x0D /* clock out */
41 #define PCF8563_REG_TMRC 0x0E /* timer control */
42 #define PCF8563_REG_TMR 0x0F /* timer */
44 #define PCF8563_SC_LV 0x80 /* low voltage */
45 #define PCF8563_MO_C 0x80 /* century */
47 static struct i2c_driver pcf8563_driver;
49 struct pcf8563 {
50 struct rtc_device *rtc;
52 * The meaning of MO_C bit varies by the chip type.
53 * From PCF8563 datasheet: this bit is toggled when the years
54 * register overflows from 99 to 00
55 * 0 indicates the century is 20xx
56 * 1 indicates the century is 19xx
57 * From RTC8564 datasheet: this bit indicates change of
58 * century. When the year digit data overflows from 99 to 00,
59 * this bit is set. By presetting it to 0 while still in the
60 * 20th century, it will be set in year 2000, ...
61 * There seems no reliable way to know how the system use this
62 * bit. So let's do it heuristically, assuming we are live in
63 * 1970...2069.
65 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
69 * In the routines that deal directly with the pcf8563 hardware, we use
70 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
72 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
74 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
75 unsigned char buf[13] = { PCF8563_REG_ST1 };
77 struct i2c_msg msgs[] = {
78 { client->addr, 0, 1, buf }, /* setup read ptr */
79 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */
82 /* read registers */
83 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
84 dev_err(&client->dev, "%s: read error\n", __func__);
85 return -EIO;
88 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
89 dev_info(&client->dev,
90 "low voltage detected, date/time is not reliable.\n");
92 dev_dbg(&client->dev,
93 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
94 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
95 __func__,
96 buf[0], buf[1], buf[2], buf[3],
97 buf[4], buf[5], buf[6], buf[7],
98 buf[8]);
101 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
102 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
103 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
104 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
105 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
106 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
107 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
108 if (tm->tm_year < 70)
109 tm->tm_year += 100; /* assume we are in 1970...2069 */
110 /* detect the polarity heuristically. see note above. */
111 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
112 (tm->tm_year >= 100) : (tm->tm_year < 100);
114 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
115 "mday=%d, mon=%d, year=%d, wday=%d\n",
116 __func__,
117 tm->tm_sec, tm->tm_min, tm->tm_hour,
118 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
120 /* the clock can give out invalid datetime, but we cannot return
121 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
123 if (rtc_valid_tm(tm) < 0)
124 dev_err(&client->dev, "retrieved date/time is not valid.\n");
126 return 0;
129 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
131 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
132 int i, err;
133 unsigned char buf[9];
135 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
136 "mday=%d, mon=%d, year=%d, wday=%d\n",
137 __func__,
138 tm->tm_sec, tm->tm_min, tm->tm_hour,
139 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
141 /* hours, minutes and seconds */
142 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
143 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
144 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
146 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
148 /* month, 1 - 12 */
149 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
151 /* year and century */
152 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
153 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
154 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
156 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
158 /* write register's data */
159 for (i = 0; i < 7; i++) {
160 unsigned char data[2] = { PCF8563_REG_SC + i,
161 buf[PCF8563_REG_SC + i] };
163 err = i2c_master_send(client, data, sizeof(data));
164 if (err != sizeof(data)) {
165 dev_err(&client->dev,
166 "%s: err=%d addr=%02x, data=%02x\n",
167 __func__, err, data[0], data[1]);
168 return -EIO;
172 return 0;
175 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
177 return pcf8563_get_datetime(to_i2c_client(dev), tm);
180 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
182 return pcf8563_set_datetime(to_i2c_client(dev), tm);
185 static const struct rtc_class_ops pcf8563_rtc_ops = {
186 .read_time = pcf8563_rtc_read_time,
187 .set_time = pcf8563_rtc_set_time,
190 static int pcf8563_probe(struct i2c_client *client,
191 const struct i2c_device_id *id)
193 struct pcf8563 *pcf8563;
195 int err = 0;
197 dev_dbg(&client->dev, "%s\n", __func__);
199 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
200 return -ENODEV;
202 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
203 if (!pcf8563)
204 return -ENOMEM;
206 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
208 i2c_set_clientdata(client, pcf8563);
210 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
211 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
213 if (IS_ERR(pcf8563->rtc)) {
214 err = PTR_ERR(pcf8563->rtc);
215 goto exit_kfree;
218 return 0;
220 exit_kfree:
221 kfree(pcf8563);
223 return err;
226 static int pcf8563_remove(struct i2c_client *client)
228 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
230 if (pcf8563->rtc)
231 rtc_device_unregister(pcf8563->rtc);
233 kfree(pcf8563);
235 return 0;
238 static const struct i2c_device_id pcf8563_id[] = {
239 { "pcf8563", 0 },
240 { "rtc8564", 0 },
243 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
245 static struct i2c_driver pcf8563_driver = {
246 .driver = {
247 .name = "rtc-pcf8563",
249 .probe = pcf8563_probe,
250 .remove = pcf8563_remove,
251 .id_table = pcf8563_id,
254 static int __init pcf8563_init(void)
256 return i2c_add_driver(&pcf8563_driver);
259 static void __exit pcf8563_exit(void)
261 i2c_del_driver(&pcf8563_driver);
264 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
265 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
266 MODULE_LICENSE("GPL");
267 MODULE_VERSION(DRV_VERSION);
269 module_init(pcf8563_init);
270 module_exit(pcf8563_exit);