Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
[deliverable/linux.git] / drivers / rtc / rtc-pcf8563.c
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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>
5a0e3ad6 20#include <linux/slab.h>
2113852b 21#include <linux/module.h>
8dccaf06 22#include <linux/of.h>
b5a82d62 23
e5fc9cc0 24#define DRV_VERSION "0.4.3"
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25
26#define PCF8563_REG_ST1 0x00 /* status */
27#define PCF8563_REG_ST2 0x01
28
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
36
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
41
42#define PCF8563_REG_CLKO 0x0D /* clock out */
43#define PCF8563_REG_TMRC 0x0E /* timer control */
44#define PCF8563_REG_TMR 0x0F /* timer */
45
46#define PCF8563_SC_LV 0x80 /* low voltage */
47#define PCF8563_MO_C 0x80 /* century */
48
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49static struct i2c_driver pcf8563_driver;
50
cbb94502 51struct pcf8563 {
e5fc9cc0 52 struct rtc_device *rtc;
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53 /*
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
65 * 1970...2069.
66 */
67 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
0f20b767 68 int voltage_low; /* incicates if a low_voltage was detected */
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69};
70
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71/*
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.
74 */
75static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
76{
e5fc9cc0 77 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
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78 unsigned char buf[13] = { PCF8563_REG_ST1 };
79
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 */
83 };
84
85 /* read registers */
86 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
2a4e2b87 87 dev_err(&client->dev, "%s: read error\n", __func__);
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88 return -EIO;
89 }
90
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91 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
92 pcf8563->voltage_low = 1;
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93 dev_info(&client->dev,
94 "low voltage detected, date/time is not reliable.\n");
0f20b767 95 }
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96
97 dev_dbg(&client->dev,
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",
2a4e2b87 100 __func__,
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101 buf[0], buf[1], buf[2], buf[3],
102 buf[4], buf[5], buf[6], buf[7],
103 buf[8]);
104
105
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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);
b5a82d62 110 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
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111 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
112 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
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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);
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118
119 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
120 "mday=%d, mon=%d, year=%d, wday=%d\n",
2a4e2b87 121 __func__,
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122 tm->tm_sec, tm->tm_min, tm->tm_hour,
123 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
124
125 /* the clock can give out invalid datetime, but we cannot return
126 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
127 */
128 if (rtc_valid_tm(tm) < 0)
129 dev_err(&client->dev, "retrieved date/time is not valid.\n");
130
131 return 0;
132}
133
134static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
135{
e5fc9cc0 136 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
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137 int i, err;
138 unsigned char buf[9];
139
140 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
141 "mday=%d, mon=%d, year=%d, wday=%d\n",
2a4e2b87 142 __func__,
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143 tm->tm_sec, tm->tm_min, tm->tm_hour,
144 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
145
146 /* hours, minutes and seconds */
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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);
b5a82d62 150
fe20ba70 151 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
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152
153 /* month, 1 - 12 */
fe20ba70 154 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
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155
156 /* year and century */
fe20ba70 157 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
cbb94502 158 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
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159 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
160
161 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
162
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] };
167
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",
2a4e2b87 172 __func__, err, data[0], data[1]);
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173 return -EIO;
174 }
175 };
176
177 return 0;
178}
179
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180#ifdef CONFIG_RTC_INTF_DEV
181static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
182{
183 struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
184 struct rtc_time tm;
185
186 switch (cmd) {
187 case RTC_VL_READ:
188 if (pcf8563->voltage_low)
189 dev_info(dev, "low voltage detected, date/time is not reliable.\n");
190
191 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
192 sizeof(int)))
193 return -EFAULT;
194 return 0;
195 case RTC_VL_CLR:
196 /*
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.
202 */
203 if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
204 pcf8563_set_datetime(to_i2c_client(dev), &tm);
205
206 /* Clear the cached value. */
207 pcf8563->voltage_low = 0;
208
209 return 0;
210 default:
211 return -ENOIOCTLCMD;
212 }
213}
214#else
215#define pcf8563_rtc_ioctl NULL
216#endif
217
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218static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
219{
220 return pcf8563_get_datetime(to_i2c_client(dev), tm);
221}
222
223static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
224{
225 return pcf8563_set_datetime(to_i2c_client(dev), tm);
226}
227
ff8371ac 228static const struct rtc_class_ops pcf8563_rtc_ops = {
0f20b767 229 .ioctl = pcf8563_rtc_ioctl,
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230 .read_time = pcf8563_rtc_read_time,
231 .set_time = pcf8563_rtc_set_time,
232};
233
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234static int pcf8563_probe(struct i2c_client *client,
235 const struct i2c_device_id *id)
b5a82d62 236{
cbb94502 237 struct pcf8563 *pcf8563;
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238
239 int err = 0;
240
e5fc9cc0 241 dev_dbg(&client->dev, "%s\n", __func__);
b5a82d62 242
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243 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
244 return -ENODEV;
b5a82d62 245
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246 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
247 if (!pcf8563)
248 return -ENOMEM;
b5a82d62 249
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250 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
251
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252 i2c_set_clientdata(client, pcf8563);
253
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254 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
255 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
b5a82d62 256
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257 if (IS_ERR(pcf8563->rtc)) {
258 err = PTR_ERR(pcf8563->rtc);
259 goto exit_kfree;
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260 }
261
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262 return 0;
263
b5a82d62 264exit_kfree:
cbb94502 265 kfree(pcf8563);
b5a82d62 266
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267 return err;
268}
269
e5fc9cc0 270static int pcf8563_remove(struct i2c_client *client)
b5a82d62 271{
e5fc9cc0 272 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
b5a82d62 273
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274 if (pcf8563->rtc)
275 rtc_device_unregister(pcf8563->rtc);
b5a82d62 276
cbb94502 277 kfree(pcf8563);
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278
279 return 0;
280}
281
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282static const struct i2c_device_id pcf8563_id[] = {
283 { "pcf8563", 0 },
8ea9212c 284 { "rtc8564", 0 },
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285 { }
286};
287MODULE_DEVICE_TABLE(i2c, pcf8563_id);
288
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289#ifdef CONFIG_OF
290static const struct of_device_id pcf8563_of_match[] __devinitconst = {
291 { .compatible = "nxp,pcf8563" },
292 {}
293};
294MODULE_DEVICE_TABLE(of, pcf8563_of_match);
295#endif
296
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297static struct i2c_driver pcf8563_driver = {
298 .driver = {
299 .name = "rtc-pcf8563",
0a25bf40 300 .owner = THIS_MODULE,
8dccaf06 301 .of_match_table = of_match_ptr(pcf8563_of_match),
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302 },
303 .probe = pcf8563_probe,
304 .remove = pcf8563_remove,
3760f736 305 .id_table = pcf8563_id,
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306};
307
0abc9201 308module_i2c_driver(pcf8563_driver);
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309
310MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
311MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
312MODULE_LICENSE("GPL");
313MODULE_VERSION(DRV_VERSION);
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