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>
21 #include <linux/module.h>
24 #define DRV_VERSION "0.4.3"
26 #define PCF8563_REG_ST1 0x00 /* status */
27 #define PCF8563_REG_ST2 0x01
29 #define PCF8563_REG_SC 0x02 /* datetime */
30 #define PCF8563_REG_MN 0x03
31 #define PCF8563_REG_HR 0x04
32 #define PCF8563_REG_DM 0x05
33 #define PCF8563_REG_DW 0x06
34 #define PCF8563_REG_MO 0x07
35 #define PCF8563_REG_YR 0x08
37 #define PCF8563_REG_AMN 0x09 /* alarm */
38 #define PCF8563_REG_AHR 0x0A
39 #define PCF8563_REG_ADM 0x0B
40 #define PCF8563_REG_ADW 0x0C
42 #define PCF8563_REG_CLKO 0x0D /* clock out */
43 #define PCF8563_REG_TMRC 0x0E /* timer control */
44 #define PCF8563_REG_TMR 0x0F /* timer */
46 #define PCF8563_SC_LV 0x80 /* low voltage */
47 #define PCF8563_MO_C 0x80 /* century */
49 static struct i2c_driver pcf8563_driver;
52 struct rtc_device *rtc;
54 * The meaning of MO_C bit varies by the chip type.
55 * From PCF8563 datasheet: this bit is toggled when the years
56 * register overflows from 99 to 00
57 * 0 indicates the century is 20xx
58 * 1 indicates the century is 19xx
59 * From RTC8564 datasheet: this bit indicates change of
60 * century. When the year digit data overflows from 99 to 00,
61 * this bit is set. By presetting it to 0 while still in the
62 * 20th century, it will be set in year 2000, ...
63 * There seems no reliable way to know how the system use this
64 * bit. So let's do it heuristically, assuming we are live in
67 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
68 int voltage_low; /* incicates if a low_voltage was detected */
72 * In the routines that deal directly with the pcf8563 hardware, we use
73 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
75 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
77 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
78 unsigned char buf[13] = { PCF8563_REG_ST1 };
80 struct i2c_msg msgs[] = {
81 { client->addr, 0, 1, buf }, /* setup read ptr */
82 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */
86 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
87 dev_err(&client->dev, "%s: read error\n", __func__);
91 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
92 pcf8563->voltage_low = 1;
93 dev_info(&client->dev,
94 "low voltage detected, date/time is not reliable.\n");
98 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
99 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
101 buf[0], buf[1], buf[2], buf[3],
102 buf[4], buf[5], buf[6], buf[7],
106 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
107 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
108 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
109 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
110 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
111 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
112 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
113 if (tm->tm_year < 70)
114 tm->tm_year += 100; /* assume we are in 1970...2069 */
115 /* detect the polarity heuristically. see note above. */
116 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
117 (tm->tm_year >= 100) : (tm->tm_year < 100);
119 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
120 "mday=%d, mon=%d, year=%d, wday=%d\n",
122 tm->tm_sec, tm->tm_min, tm->tm_hour,
123 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
125 /* the clock can give out invalid datetime, but we cannot return
126 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
128 if (rtc_valid_tm(tm) < 0)
129 dev_err(&client->dev, "retrieved date/time is not valid.\n");
134 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
136 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
138 unsigned char buf[9];
140 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
141 "mday=%d, mon=%d, year=%d, wday=%d\n",
143 tm->tm_sec, tm->tm_min, tm->tm_hour,
144 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
146 /* hours, minutes and seconds */
147 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
148 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
149 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
151 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
154 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
156 /* year and century */
157 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
158 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
159 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
161 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
163 /* write register's data */
164 for (i = 0; i < 7; i++) {
165 unsigned char data[2] = { PCF8563_REG_SC + i,
166 buf[PCF8563_REG_SC + i] };
168 err = i2c_master_send(client, data, sizeof(data));
169 if (err != sizeof(data)) {
170 dev_err(&client->dev,
171 "%s: err=%d addr=%02x, data=%02x\n",
172 __func__, err, data[0], data[1]);
180 #ifdef CONFIG_RTC_INTF_DEV
181 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
183 struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
188 if (pcf8563->voltage_low)
189 dev_info(dev, "low voltage detected, date/time is not reliable.\n");
191 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
197 * Clear the VL bit in the seconds register in case
198 * the time has not been set already (which would
199 * have cleared it). This does not really matter
200 * because of the cached voltage_low value but do it
201 * anyway for consistency.
203 if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
204 pcf8563_set_datetime(to_i2c_client(dev), &tm);
206 /* Clear the cached value. */
207 pcf8563->voltage_low = 0;
215 #define pcf8563_rtc_ioctl NULL
218 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
220 return pcf8563_get_datetime(to_i2c_client(dev), tm);
223 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
225 return pcf8563_set_datetime(to_i2c_client(dev), tm);
228 static const struct rtc_class_ops pcf8563_rtc_ops = {
229 .ioctl = pcf8563_rtc_ioctl,
230 .read_time = pcf8563_rtc_read_time,
231 .set_time = pcf8563_rtc_set_time,
234 static int pcf8563_probe(struct i2c_client *client,
235 const struct i2c_device_id *id)
237 struct pcf8563 *pcf8563;
241 dev_dbg(&client->dev, "%s\n", __func__);
243 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
246 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
250 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
252 i2c_set_clientdata(client, pcf8563);
254 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
255 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
257 if (IS_ERR(pcf8563->rtc)) {
258 err = PTR_ERR(pcf8563->rtc);
270 static int pcf8563_remove(struct i2c_client *client)
272 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
275 rtc_device_unregister(pcf8563->rtc);
282 static const struct i2c_device_id pcf8563_id[] = {
287 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
290 static const struct of_device_id pcf8563_of_match[] __devinitconst = {
291 { .compatible = "nxp,pcf8563" },
294 MODULE_DEVICE_TABLE(of, pcf8563_of_match);
297 static struct i2c_driver pcf8563_driver = {
299 .name = "rtc-pcf8563",
300 .owner = THIS_MODULE,
301 .of_match_table = of_match_ptr(pcf8563_of_match),
303 .probe = pcf8563_probe,
304 .remove = pcf8563_remove,
305 .id_table = pcf8563_id,
308 module_i2c_driver(pcf8563_driver);
310 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
311 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
312 MODULE_LICENSE("GPL");
313 MODULE_VERSION(DRV_VERSION);