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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>
Paul Gortmaker21138522011-05-27 09:57:25 -040014#include <linux/module.h>
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080015
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070016#define DRV_VERSION "0.4"
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080017
18/* Registers */
19
20#define DS1672_REG_CNT_BASE 0
21#define DS1672_REG_CONTROL 4
22#define DS1672_REG_TRICKLE 5
23
Alessandro Zummo39035862006-04-10 22:54:41 -070024#define DS1672_REG_CONTROL_EOSC 0x80
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080025
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070026static struct i2c_driver ds1672_driver;
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080027
28/*
29 * In the routines that deal directly with the ds1672 hardware, we use
30 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
31 * Epoch is initialized as 2000. Time is set to UTC.
32 */
33static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
34{
35 unsigned long time;
36 unsigned char addr = DS1672_REG_CNT_BASE;
37 unsigned char buf[4];
38
39 struct i2c_msg msgs[] = {
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070040 {client->addr, 0, 1, &addr}, /* setup read ptr */
41 {client->addr, I2C_M_RD, 4, buf}, /* read date */
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080042 };
43
44 /* read date registers */
45 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070046 dev_err(&client->dev, "%s: read error\n", __func__);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080047 return -EIO;
48 }
49
50 dev_dbg(&client->dev,
Jeff Garzik11966ad2006-10-04 04:41:53 -040051 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070052 __func__, buf[0], buf[1], buf[2], buf[3]);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080053
54 time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
55
56 rtc_time_to_tm(time, tm);
57
58 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
59 "mday=%d, mon=%d, year=%d, wday=%d\n",
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070060 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080061 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
62
63 return 0;
64}
65
66static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
67{
68 int xfer;
Kumar Gala8a95b252006-04-10 22:54:39 -070069 unsigned char buf[6];
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080070
71 buf[0] = DS1672_REG_CNT_BASE;
72 buf[1] = secs & 0x000000FF;
73 buf[2] = (secs & 0x0000FF00) >> 8;
74 buf[3] = (secs & 0x00FF0000) >> 16;
75 buf[4] = (secs & 0xFF000000) >> 24;
Alessandro Zummo1716b0f2008-10-15 22:03:10 -070076 buf[5] = 0; /* set control reg to enable counting */
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080077
Kumar Gala8a95b252006-04-10 22:54:39 -070078 xfer = i2c_master_send(client, buf, 6);
79 if (xfer != 6) {
Harvey Harrison2a4e2b82008-04-28 02:12:00 -070080 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080081 return -EIO;
82 }
83
84 return 0;
85}
86
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080087static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
88{
89 return ds1672_get_datetime(to_i2c_client(dev), tm);
90}
91
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -080092static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
93{
94 return ds1672_set_mmss(to_i2c_client(dev), secs);
95}
96
Kumar Gala8a95b252006-04-10 22:54:39 -070097static int ds1672_get_control(struct i2c_client *client, u8 *status)
98{
99 unsigned char addr = DS1672_REG_CONTROL;
100
101 struct i2c_msg msgs[] = {
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700102 {client->addr, 0, 1, &addr}, /* setup read ptr */
103 {client->addr, I2C_M_RD, 1, status}, /* read control */
Kumar Gala8a95b252006-04-10 22:54:39 -0700104 };
105
106 /* read control register */
107 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
Harvey Harrison2a4e2b82008-04-28 02:12:00 -0700108 dev_err(&client->dev, "%s: read error\n", __func__);
Kumar Gala8a95b252006-04-10 22:54:39 -0700109 return -EIO;
110 }
111
112 return 0;
113}
114
115/* following are the sysfs callback functions */
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700116static ssize_t show_control(struct device *dev, struct device_attribute *attr,
117 char *buf)
Kumar Gala8a95b252006-04-10 22:54:39 -0700118{
119 struct i2c_client *client = to_i2c_client(dev);
Kumar Gala8a95b252006-04-10 22:54:39 -0700120 u8 control;
121 int err;
122
123 err = ds1672_get_control(client, &control);
124 if (err)
125 return err;
126
Alessandro Zummo39035862006-04-10 22:54:41 -0700127 return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700128 ? "disabled" : "enabled");
Kumar Gala8a95b252006-04-10 22:54:39 -0700129}
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700130
Kumar Gala8a95b252006-04-10 22:54:39 -0700131static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
132
David Brownellff8371a2006-09-30 23:28:17 -0700133static const struct rtc_class_ops ds1672_rtc_ops = {
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700134 .read_time = ds1672_rtc_read_time,
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700135 .set_mmss = ds1672_rtc_set_mmss,
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800136};
137
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700138static int ds1672_remove(struct i2c_client *client)
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800139{
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800140 struct rtc_device *rtc = i2c_get_clientdata(client);
141
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700142 if (rtc)
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800143 rtc_device_unregister(rtc);
144
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800145 return 0;
146}
147
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700148static int ds1672_probe(struct i2c_client *client,
149 const struct i2c_device_id *id)
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800150{
151 int err = 0;
Kumar Gala8a95b252006-04-10 22:54:39 -0700152 u8 control;
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800153 struct rtc_device *rtc;
154
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700155 dev_dbg(&client->dev, "%s\n", __func__);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800156
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700157 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
158 return -ENODEV;
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800159
160 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
161
162 rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev,
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700163 &ds1672_rtc_ops, THIS_MODULE);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800164
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700165 if (IS_ERR(rtc))
166 return PTR_ERR(rtc);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800167
168 i2c_set_clientdata(client, rtc);
169
Kumar Gala8a95b252006-04-10 22:54:39 -0700170 /* read control register */
171 err = ds1672_get_control(client, &control);
Alessandro Zummo39035862006-04-10 22:54:41 -0700172 if (err)
Jeff Garzik91046a82006-12-06 20:35:34 -0800173 goto exit_devreg;
Kumar Gala8a95b252006-04-10 22:54:39 -0700174
175 if (control & DS1672_REG_CONTROL_EOSC)
176 dev_warn(&client->dev, "Oscillator not enabled. "
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700177 "Set time to enable.\n");
Kumar Gala8a95b252006-04-10 22:54:39 -0700178
179 /* Register sysfs hooks */
Jeff Garzik91046a82006-12-06 20:35:34 -0800180 err = device_create_file(&client->dev, &dev_attr_control);
181 if (err)
182 goto exit_devreg;
Kumar Gala8a95b252006-04-10 22:54:39 -0700183
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800184 return 0;
185
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700186 exit_devreg:
Jeff Garzik91046a82006-12-06 20:35:34 -0800187 rtc_device_unregister(rtc);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800188 return err;
189}
190
Alessandro Zummofe102c72008-12-09 13:14:11 -0800191static struct i2c_device_id ds1672_id[] = {
192 { "ds1672", 0 },
193 { }
194};
195
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700196static struct i2c_driver ds1672_driver = {
197 .driver = {
198 .name = "rtc-ds1672",
199 },
200 .probe = &ds1672_probe,
201 .remove = &ds1672_remove,
Alessandro Zummofe102c72008-12-09 13:14:11 -0800202 .id_table = ds1672_id,
Alessandro Zummo1716b0f2008-10-15 22:03:10 -0700203};
204
Axel Lin0abc9202012-03-23 15:02:31 -0700205module_i2c_driver(ds1672_driver);
Alessandro Zummoedf1aaa2006-03-27 01:16:43 -0800206
207MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
208MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
209MODULE_LICENSE("GPL");
210MODULE_VERSION(DRV_VERSION);