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>
23 #define DRV_VERSION "0.4.3"
25 #define PCF8563_REG_ST1 0x00 /* status */
26 #define PCF8563_REG_ST2 0x01
28 #define PCF8563_REG_SC 0x02 /* datetime */
29 #define PCF8563_REG_MN 0x03
30 #define PCF8563_REG_HR 0x04
31 #define PCF8563_REG_DM 0x05
32 #define PCF8563_REG_DW 0x06
33 #define PCF8563_REG_MO 0x07
34 #define PCF8563_REG_YR 0x08
36 #define PCF8563_REG_AMN 0x09 /* alarm */
37 #define PCF8563_REG_AHR 0x0A
38 #define PCF8563_REG_ADM 0x0B
39 #define PCF8563_REG_ADW 0x0C
41 #define PCF8563_REG_CLKO 0x0D /* clock out */
42 #define PCF8563_REG_TMRC 0x0E /* timer control */
43 #define PCF8563_REG_TMR 0x0F /* timer */
45 #define PCF8563_SC_LV 0x80 /* low voltage */
46 #define PCF8563_MO_C 0x80 /* century */
48 static struct i2c_driver pcf8563_driver
;
51 struct rtc_device
*rtc
;
53 * The meaning of MO_C bit varies by the chip type.
54 * From PCF8563 datasheet: this bit is toggled when the years
55 * register overflows from 99 to 00
56 * 0 indicates the century is 20xx
57 * 1 indicates the century is 19xx
58 * From RTC8564 datasheet: this bit indicates change of
59 * century. When the year digit data overflows from 99 to 00,
60 * this bit is set. By presetting it to 0 while still in the
61 * 20th century, it will be set in year 2000, ...
62 * There seems no reliable way to know how the system use this
63 * bit. So let's do it heuristically, assuming we are live in
66 int c_polarity
; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
67 int voltage_low
; /* incicates if a low_voltage was detected */
71 * In the routines that deal directly with the pcf8563 hardware, we use
72 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
74 static int pcf8563_get_datetime(struct i2c_client
*client
, struct rtc_time
*tm
)
76 struct pcf8563
*pcf8563
= i2c_get_clientdata(client
);
77 unsigned char buf
[13] = { PCF8563_REG_ST1
};
79 struct i2c_msg msgs
[] = {
80 { client
->addr
, 0, 1, buf
}, /* setup read ptr */
81 { client
->addr
, I2C_M_RD
, 13, buf
}, /* read status + date */
85 if ((i2c_transfer(client
->adapter
, msgs
, 2)) != 2) {
86 dev_err(&client
->dev
, "%s: read error\n", __func__
);
90 if (buf
[PCF8563_REG_SC
] & PCF8563_SC_LV
) {
91 pcf8563
->voltage_low
= 1;
92 dev_info(&client
->dev
,
93 "low voltage detected, date/time is not reliable.\n");
97 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
98 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
100 buf
[0], buf
[1], buf
[2], buf
[3],
101 buf
[4], buf
[5], buf
[6], buf
[7],
105 tm
->tm_sec
= bcd2bin(buf
[PCF8563_REG_SC
] & 0x7F);
106 tm
->tm_min
= bcd2bin(buf
[PCF8563_REG_MN
] & 0x7F);
107 tm
->tm_hour
= bcd2bin(buf
[PCF8563_REG_HR
] & 0x3F); /* rtc hr 0-23 */
108 tm
->tm_mday
= bcd2bin(buf
[PCF8563_REG_DM
] & 0x3F);
109 tm
->tm_wday
= buf
[PCF8563_REG_DW
] & 0x07;
110 tm
->tm_mon
= bcd2bin(buf
[PCF8563_REG_MO
] & 0x1F) - 1; /* rtc mn 1-12 */
111 tm
->tm_year
= bcd2bin(buf
[PCF8563_REG_YR
]);
112 if (tm
->tm_year
< 70)
113 tm
->tm_year
+= 100; /* assume we are in 1970...2069 */
114 /* detect the polarity heuristically. see note above. */
115 pcf8563
->c_polarity
= (buf
[PCF8563_REG_MO
] & PCF8563_MO_C
) ?
116 (tm
->tm_year
>= 100) : (tm
->tm_year
< 100);
118 dev_dbg(&client
->dev
, "%s: tm is secs=%d, mins=%d, hours=%d, "
119 "mday=%d, mon=%d, year=%d, wday=%d\n",
121 tm
->tm_sec
, tm
->tm_min
, tm
->tm_hour
,
122 tm
->tm_mday
, tm
->tm_mon
, tm
->tm_year
, tm
->tm_wday
);
124 /* the clock can give out invalid datetime, but we cannot return
125 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
127 if (rtc_valid_tm(tm
) < 0)
128 dev_err(&client
->dev
, "retrieved date/time is not valid.\n");
133 static int pcf8563_set_datetime(struct i2c_client
*client
, struct rtc_time
*tm
)
135 struct pcf8563
*pcf8563
= i2c_get_clientdata(client
);
137 unsigned char buf
[9];
139 dev_dbg(&client
->dev
, "%s: secs=%d, mins=%d, hours=%d, "
140 "mday=%d, mon=%d, year=%d, wday=%d\n",
142 tm
->tm_sec
, tm
->tm_min
, tm
->tm_hour
,
143 tm
->tm_mday
, tm
->tm_mon
, tm
->tm_year
, tm
->tm_wday
);
145 /* hours, minutes and seconds */
146 buf
[PCF8563_REG_SC
] = bin2bcd(tm
->tm_sec
);
147 buf
[PCF8563_REG_MN
] = bin2bcd(tm
->tm_min
);
148 buf
[PCF8563_REG_HR
] = bin2bcd(tm
->tm_hour
);
150 buf
[PCF8563_REG_DM
] = bin2bcd(tm
->tm_mday
);
153 buf
[PCF8563_REG_MO
] = bin2bcd(tm
->tm_mon
+ 1);
155 /* year and century */
156 buf
[PCF8563_REG_YR
] = bin2bcd(tm
->tm_year
% 100);
157 if (pcf8563
->c_polarity
? (tm
->tm_year
>= 100) : (tm
->tm_year
< 100))
158 buf
[PCF8563_REG_MO
] |= PCF8563_MO_C
;
160 buf
[PCF8563_REG_DW
] = tm
->tm_wday
& 0x07;
162 /* write register's data */
163 for (i
= 0; i
< 7; i
++) {
164 unsigned char data
[2] = { PCF8563_REG_SC
+ i
,
165 buf
[PCF8563_REG_SC
+ i
] };
167 err
= i2c_master_send(client
, data
, sizeof(data
));
168 if (err
!= sizeof(data
)) {
169 dev_err(&client
->dev
,
170 "%s: err=%d addr=%02x, data=%02x\n",
171 __func__
, err
, data
[0], data
[1]);
179 #ifdef CONFIG_RTC_INTF_DEV
180 static int pcf8563_rtc_ioctl(struct device
*dev
, unsigned int cmd
, unsigned long arg
)
182 struct pcf8563
*pcf8563
= i2c_get_clientdata(to_i2c_client(dev
));
187 if (pcf8563
->voltage_low
)
188 dev_info(dev
, "low voltage detected, date/time is not reliable.\n");
190 if (copy_to_user((void __user
*)arg
, &pcf8563
->voltage_low
,
196 * Clear the VL bit in the seconds register in case
197 * the time has not been set already (which would
198 * have cleared it). This does not really matter
199 * because of the cached voltage_low value but do it
200 * anyway for consistency.
202 if (pcf8563_get_datetime(to_i2c_client(dev
), &tm
))
203 pcf8563_set_datetime(to_i2c_client(dev
), &tm
);
205 /* Clear the cached value. */
206 pcf8563
->voltage_low
= 0;
214 #define pcf8563_rtc_ioctl NULL
217 static int pcf8563_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
219 return pcf8563_get_datetime(to_i2c_client(dev
), tm
);
222 static int pcf8563_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
224 return pcf8563_set_datetime(to_i2c_client(dev
), tm
);
227 static const struct rtc_class_ops pcf8563_rtc_ops
= {
228 .ioctl
= pcf8563_rtc_ioctl
,
229 .read_time
= pcf8563_rtc_read_time
,
230 .set_time
= pcf8563_rtc_set_time
,
233 static int pcf8563_probe(struct i2c_client
*client
,
234 const struct i2c_device_id
*id
)
236 struct pcf8563
*pcf8563
;
240 dev_dbg(&client
->dev
, "%s\n", __func__
);
242 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_I2C
))
245 pcf8563
= kzalloc(sizeof(struct pcf8563
), GFP_KERNEL
);
249 dev_info(&client
->dev
, "chip found, driver version " DRV_VERSION
"\n");
251 i2c_set_clientdata(client
, pcf8563
);
253 pcf8563
->rtc
= rtc_device_register(pcf8563_driver
.driver
.name
,
254 &client
->dev
, &pcf8563_rtc_ops
, THIS_MODULE
);
256 if (IS_ERR(pcf8563
->rtc
)) {
257 err
= PTR_ERR(pcf8563
->rtc
);
269 static int pcf8563_remove(struct i2c_client
*client
)
271 struct pcf8563
*pcf8563
= i2c_get_clientdata(client
);
274 rtc_device_unregister(pcf8563
->rtc
);
281 static const struct i2c_device_id pcf8563_id
[] = {
286 MODULE_DEVICE_TABLE(i2c
, pcf8563_id
);
288 static struct i2c_driver pcf8563_driver
= {
290 .name
= "rtc-pcf8563",
292 .probe
= pcf8563_probe
,
293 .remove
= pcf8563_remove
,
294 .id_table
= pcf8563_id
,
297 module_i2c_driver(pcf8563_driver
);
299 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
300 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
301 MODULE_LICENSE("GPL");
302 MODULE_VERSION(DRV_VERSION
);