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Alessandro Zummoedf1aaa2006-03-27 01:16:43 -08001/*
2 * An rtc/i2c driver for the Dallas DS1672
Alessandro Zummo39035862006-04-10 22:54:41 -07003 * Copyright 2005-06 Tower Technologies
4 *
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -08006 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080012#include <linux/i2c.h>
13#include <linux/rtc.h>
14
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070015#define DRV_VERSION "0.4"
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080016
17/* Registers */
18
19#define DS1672_REG_CNT_BASE 0
20#define DS1672_REG_CONTROL 4
21#define DS1672_REG_TRICKLE 5
22
Alessandro Zummo39035862006-04-10 22:54:41 -070023#define DS1672_REG_CONTROL_EOSC 0x80
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080024
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070025static struct i2c_driver ds1672_driver;
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080026
27/*
28 * In the routines that deal directly with the ds1672 hardware, we use
29 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
30 * Epoch is initialized as 2000. Time is set to UTC.
31 */
32static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
33{
34 unsigned long time;
35 unsigned char addr = DS1672_REG_CNT_BASE;
36 unsigned char buf[4];
37
38 struct i2c_msg msgs[] = {
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070039 {client->addr, 0, 1, &addr}, /* setup read ptr */
40 {client->addr, I2C_M_RD, 4, buf}, /* read date */
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080041 };
42
43 /* read date registers */
44 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070045 dev_err(&client->dev, "%s: read error\n", __func__);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080046 return -EIO;
47 }
48
49 dev_dbg(&client->dev,
Jeff Garzik11966ad2006-10-04 04:41:53 -040050 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070051 __func__, buf[0], buf[1], buf[2], buf[3]);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080052
53 time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
54
55 rtc_time_to_tm(time, tm);
56
57 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
58 "mday=%d, mon=%d, year=%d, wday=%d\n",
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070059 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080060 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
61
62 return 0;
63}
64
65static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
66{
67 int xfer;
Kumar Gala8a95b252006-04-10 22:54:39 -070068 unsigned char buf[6];
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080069
70 buf[0] = DS1672_REG_CNT_BASE;
71 buf[1] = secs & 0x000000FF;
72 buf[2] = (secs & 0x0000FF00) >> 8;
73 buf[3] = (secs & 0x00FF0000) >> 16;
74 buf[4] = (secs & 0xFF000000) >> 24;
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070075 buf[5] = 0; /* set control reg to enable counting */
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080076
Kumar Gala8a95b252006-04-10 22:54:39 -070077 xfer = i2c_master_send(client, buf, 6);
78 if (xfer != 6) {
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070079 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080080 return -EIO;
81 }
82
83 return 0;
84}
85
86static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm)
87{
88 unsigned long secs;
89
90 dev_dbg(&client->dev,
Jeff Garzik11966ad2006-10-04 04:41:53 -040091 "%s: secs=%d, mins=%d, hours=%d, "
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080092 "mday=%d, mon=%d, year=%d, wday=%d\n",
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070093 __func__,
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080094 tm->tm_sec, tm->tm_min, tm->tm_hour,
95 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
96
97 rtc_tm_to_time(tm, &secs);
98
99 return ds1672_set_mmss(client, secs);
100}
101
102static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
103{
104 return ds1672_get_datetime(to_i2c_client(dev), tm);
105}
106
107static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm)
108{
109 return ds1672_set_datetime(to_i2c_client(dev), tm);
110}
111
112static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
113{
114 return ds1672_set_mmss(to_i2c_client(dev), secs);
115}
116
Kumar Gala8a95b252006-04-10 22:54:39 -0700117static int ds1672_get_control(struct i2c_client *client, u8 *status)
118{
119 unsigned char addr = DS1672_REG_CONTROL;
120
121 struct i2c_msg msgs[] = {
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700122 {client->addr, 0, 1, &addr}, /* setup read ptr */
123 {client->addr, I2C_M_RD, 1, status}, /* read control */
Kumar Gala8a95b252006-04-10 22:54:39 -0700124 };
125
126 /* read control register */
127 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
Harvey Harrison2a4e2b82008-04-28 02:12:00 -0700128 dev_err(&client->dev, "%s: read error\n", __func__);
Kumar Gala8a95b252006-04-10 22:54:39 -0700129 return -EIO;
130 }
131
132 return 0;
133}
134
135/* following are the sysfs callback functions */
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700136static ssize_t show_control(struct device *dev, struct device_attribute *attr,
137 char *buf)
Kumar Gala8a95b252006-04-10 22:54:39 -0700138{
139 struct i2c_client *client = to_i2c_client(dev);
Kumar Gala8a95b252006-04-10 22:54:39 -0700140 u8 control;
141 int err;
142
143 err = ds1672_get_control(client, &control);
144 if (err)
145 return err;
146
Alessandro Zummo39035862006-04-10 22:54:41 -0700147 return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700148 ? "disabled" : "enabled");
Kumar Gala8a95b252006-04-10 22:54:39 -0700149}
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700150
Kumar Gala8a95b252006-04-10 22:54:39 -0700151static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
152
David Brownellff8371a2006-09-30 23:28:17 -0700153static const struct rtc_class_ops ds1672_rtc_ops = {
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700154 .read_time = ds1672_rtc_read_time,
155 .set_time = ds1672_rtc_set_time,
156 .set_mmss = ds1672_rtc_set_mmss,
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800157};
158
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700159static int ds1672_remove(struct i2c_client *client)
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800160{
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800161 struct rtc_device *rtc = i2c_get_clientdata(client);
162
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700163 if (rtc)
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800164 rtc_device_unregister(rtc);
165
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800166 return 0;
167}
168
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700169static int ds1672_probe(struct i2c_client *client,
170 const struct i2c_device_id *id)
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800171{
172 int err = 0;
Kumar Gala8a95b252006-04-10 22:54:39 -0700173 u8 control;
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800174 struct rtc_device *rtc;
175
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700176 dev_dbg(&client->dev, "%s\n", __func__);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800177
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700178 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
179 return -ENODEV;
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800180
181 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
182
183 rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev,
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700184 &ds1672_rtc_ops, THIS_MODULE);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800185
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700186 if (IS_ERR(rtc))
187 return PTR_ERR(rtc);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800188
189 i2c_set_clientdata(client, rtc);
190
Kumar Gala8a95b252006-04-10 22:54:39 -0700191 /* read control register */
192 err = ds1672_get_control(client, &control);
Alessandro Zummo39035862006-04-10 22:54:41 -0700193 if (err)
Jeff Garzik91046a82006-12-06 20:35:34 -0800194 goto exit_devreg;
Kumar Gala8a95b252006-04-10 22:54:39 -0700195
196 if (control & DS1672_REG_CONTROL_EOSC)
197 dev_warn(&client->dev, "Oscillator not enabled. "
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700198 "Set time to enable.\n");
Kumar Gala8a95b252006-04-10 22:54:39 -0700199
200 /* Register sysfs hooks */
Jeff Garzik91046a82006-12-06 20:35:34 -0800201 err = device_create_file(&client->dev, &dev_attr_control);
202 if (err)
203 goto exit_devreg;
Kumar Gala8a95b252006-04-10 22:54:39 -0700204
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800205 return 0;
206
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700207 exit_devreg:
Jeff Garzik91046a82006-12-06 20:35:34 -0800208 rtc_device_unregister(rtc);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800209 return err;
210}
211
Alessandro Zummofe102c72008-12-09 13:14:11 -0800212static struct i2c_device_id ds1672_id[] = {
213 { "ds1672", 0 },
214 { }
215};
216
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700217static struct i2c_driver ds1672_driver = {
218 .driver = {
219 .name = "rtc-ds1672",
220 },
221 .probe = &ds1672_probe,
222 .remove = &ds1672_remove,
Alessandro Zummofe102c72008-12-09 13:14:11 -0800223 .id_table = ds1672_id,
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700224};
225
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800226static int __init ds1672_init(void)
227{
228 return i2c_add_driver(&ds1672_driver);
229}
230
231static void __exit ds1672_exit(void)
232{
233 i2c_del_driver(&ds1672_driver);
234}
235
236MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
237MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
238MODULE_LICENSE("GPL");
239MODULE_VERSION(DRV_VERSION);
240
241module_init(ds1672_init);
242module_exit(ds1672_exit);