1 /*
2 * An I2C driver for the Philips PCF8563 RTC
3 * Copyright 2005-06 Tower Technologies
4 *
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
6 * Maintainers: http://www.nslu2-linux.org/
7 *
8 * based on the other drivers in this same directory.
9 *
10 * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
11 *
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.
15 */
16
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>
22
23 #define DRV_VERSION "0.4.3"
24
25 #define PCF8563_REG_ST1 0x00 /* status */
26 #define PCF8563_REG_ST2 0x01
27
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
35
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
40
41 #define PCF8563_REG_CLKO 0x0D /* clock out */
42 #define PCF8563_REG_TMRC 0x0E /* timer control */
43 #define PCF8563_REG_TMR 0x0F /* timer */
44
45 #define PCF8563_SC_LV 0x80 /* low voltage */
46 #define PCF8563_MO_C 0x80 /* century */
47
48 static struct i2c_driver pcf8563_driver;
49
50 struct pcf8563 {
51 struct rtc_device *rtc;
52 /*
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
64 * 1970...2069.
65 */
66 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
67 };
68
69 /*
70 * In the routines that deal directly with the pcf8563 hardware, we use
71 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
72 */
pcf8563_get_datetime(struct i2c_client * client,struct rtc_time * tm)73 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
74 {
75 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
76 unsigned char buf[13] = { PCF8563_REG_ST1 };
77
78 struct i2c_msg msgs[] = {
79 { client->addr, 0, 1, buf }, /* setup read ptr */
80 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */
81 };
82
83 /* read registers */
84 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
85 dev_err(&client->dev, "%s: read error\n", __func__);
86 return -EIO;
87 }
88
89 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
90 dev_info(&client->dev,
91 "low voltage detected, date/time is not reliable.\n");
92
93 dev_dbg(&client->dev,
94 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
95 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
96 __func__,
97 buf[0], buf[1], buf[2], buf[3],
98 buf[4], buf[5], buf[6], buf[7],
99 buf[8]);
100
101
102 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
103 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
104 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
105 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
106 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
107 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
108 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
109 if (tm->tm_year < 70)
110 tm->tm_year += 100; /* assume we are in 1970...2069 */
111 /* detect the polarity heuristically. see note above. */
112 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
113 (tm->tm_year >= 100) : (tm->tm_year < 100);
114
115 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
116 "mday=%d, mon=%d, year=%d, wday=%d\n",
117 __func__,
118 tm->tm_sec, tm->tm_min, tm->tm_hour,
119 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
120
121 /* the clock can give out invalid datetime, but we cannot return
122 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
123 */
124 if (rtc_valid_tm(tm) < 0)
125 dev_err(&client->dev, "retrieved date/time is not valid.\n");
126
127 return 0;
128 }
129
pcf8563_set_datetime(struct i2c_client * client,struct rtc_time * tm)130 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
131 {
132 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
133 int i, err;
134 unsigned char buf[9];
135
136 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
137 "mday=%d, mon=%d, year=%d, wday=%d\n",
138 __func__,
139 tm->tm_sec, tm->tm_min, tm->tm_hour,
140 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
141
142 /* hours, minutes and seconds */
143 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
144 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
145 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
146
147 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
148
149 /* month, 1 - 12 */
150 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
151
152 /* year and century */
153 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
154 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
155 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
156
157 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
158
159 /* write register's data */
160 for (i = 0; i < 7; i++) {
161 unsigned char data[2] = { PCF8563_REG_SC + i,
162 buf[PCF8563_REG_SC + i] };
163
164 err = i2c_master_send(client, data, sizeof(data));
165 if (err != sizeof(data)) {
166 dev_err(&client->dev,
167 "%s: err=%d addr=%02x, data=%02x\n",
168 __func__, err, data[0], data[1]);
169 return -EIO;
170 }
171 };
172
173 return 0;
174 }
175
pcf8563_rtc_read_time(struct device * dev,struct rtc_time * tm)176 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
177 {
178 return pcf8563_get_datetime(to_i2c_client(dev), tm);
179 }
180
pcf8563_rtc_set_time(struct device * dev,struct rtc_time * tm)181 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
182 {
183 return pcf8563_set_datetime(to_i2c_client(dev), tm);
184 }
185
186 static const struct rtc_class_ops pcf8563_rtc_ops = {
187 .read_time = pcf8563_rtc_read_time,
188 .set_time = pcf8563_rtc_set_time,
189 };
190
pcf8563_probe(struct i2c_client * client,const struct i2c_device_id * id)191 static int pcf8563_probe(struct i2c_client *client,
192 const struct i2c_device_id *id)
193 {
194 struct pcf8563 *pcf8563;
195
196 int err = 0;
197
198 dev_dbg(&client->dev, "%s\n", __func__);
199
200 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
201 return -ENODEV;
202
203 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
204 if (!pcf8563)
205 return -ENOMEM;
206
207 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
208
209 i2c_set_clientdata(client, pcf8563);
210
211 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
212 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
213
214 if (IS_ERR(pcf8563->rtc)) {
215 err = PTR_ERR(pcf8563->rtc);
216 goto exit_kfree;
217 }
218
219 return 0;
220
221 exit_kfree:
222 kfree(pcf8563);
223
224 return err;
225 }
226
pcf8563_remove(struct i2c_client * client)227 static int pcf8563_remove(struct i2c_client *client)
228 {
229 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
230
231 if (pcf8563->rtc)
232 rtc_device_unregister(pcf8563->rtc);
233
234 kfree(pcf8563);
235
236 return 0;
237 }
238
239 static const struct i2c_device_id pcf8563_id[] = {
240 { "pcf8563", 0 },
241 { "rtc8564", 0 },
242 { }
243 };
244 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
245
246 static struct i2c_driver pcf8563_driver = {
247 .driver = {
248 .name = "rtc-pcf8563",
249 },
250 .probe = pcf8563_probe,
251 .remove = pcf8563_remove,
252 .id_table = pcf8563_id,
253 };
254
255 module_i2c_driver(pcf8563_driver);
256
257 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
258 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
259 MODULE_LICENSE("GPL");
260 MODULE_VERSION(DRV_VERSION);
261