2 * An rtc/i2c driver for the Dallas DS1672
3 * Copyright 2005-06 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
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.
12 #include <linux/i2c.h>
13 #include <linux/rtc.h>
14 #include <linux/module.h>
18 #define DS1672_REG_CNT_BASE 0
19 #define DS1672_REG_CONTROL 4
20 #define DS1672_REG_TRICKLE 5
22 #define DS1672_REG_CONTROL_EOSC 0x80
25 * In the routines that deal directly with the ds1672 hardware, we use
26 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
29 static int ds1672_read_time(struct device *dev, struct rtc_time *tm)
31 struct i2c_client *client = to_i2c_client(dev);
33 unsigned char addr = DS1672_REG_CONTROL;
36 struct i2c_msg msgs[] = {
50 /* read control register */
51 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
52 dev_warn(&client->dev, "Unable to read the control register\n");
56 if (buf[0] & DS1672_REG_CONTROL_EOSC) {
57 dev_warn(&client->dev, "Oscillator not enabled. Set time to enable.\n");
61 addr = DS1672_REG_CNT_BASE;
64 /* read date registers */
65 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
66 dev_err(&client->dev, "%s: read error\n", __func__);
71 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
72 __func__, buf[0], buf[1], buf[2], buf[3]);
74 time = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
75 (buf[1] << 8) | buf[0];
77 rtc_time_to_tm(time, tm);
79 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
80 "mday=%d, mon=%d, year=%d, wday=%d\n",
81 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
82 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
87 static int ds1672_set_mmss(struct device *dev, unsigned long secs)
89 struct i2c_client *client = to_i2c_client(dev);
93 buf[0] = DS1672_REG_CNT_BASE;
94 buf[1] = secs & 0x000000FF;
95 buf[2] = (secs & 0x0000FF00) >> 8;
96 buf[3] = (secs & 0x00FF0000) >> 16;
97 buf[4] = (secs & 0xFF000000) >> 24;
98 buf[5] = 0; /* set control reg to enable counting */
100 xfer = i2c_master_send(client, buf, 6);
102 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
109 static const struct rtc_class_ops ds1672_rtc_ops = {
110 .read_time = ds1672_read_time,
111 .set_mmss = ds1672_set_mmss,
114 static int ds1672_probe(struct i2c_client *client,
115 const struct i2c_device_id *id)
118 struct rtc_device *rtc;
120 dev_dbg(&client->dev, "%s\n", __func__);
122 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
125 rtc = devm_rtc_allocate_device(&client->dev);
129 rtc->ops = &ds1672_rtc_ops;
130 rtc->range_max = U32_MAX;
132 err = rtc_register_device(rtc);
139 i2c_set_clientdata(client, rtc);
144 static const struct i2c_device_id ds1672_id[] = {
148 MODULE_DEVICE_TABLE(i2c, ds1672_id);
150 static const struct of_device_id ds1672_of_match[] = {
151 { .compatible = "dallas,ds1672" },
154 MODULE_DEVICE_TABLE(of, ds1672_of_match);
156 static struct i2c_driver ds1672_driver = {
158 .name = "rtc-ds1672",
159 .of_match_table = of_match_ptr(ds1672_of_match),
161 .probe = &ds1672_probe,
162 .id_table = ds1672_id,
165 module_i2c_driver(ds1672_driver);
167 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
168 MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
169 MODULE_LICENSE("GPL");