278 lines
6.4 KiB
C
278 lines
6.4 KiB
C
/*
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* An rtc/i2c driver for the Dallas DS1672
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* Copyright 2005-06 Tower Technologies
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*
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* Author: Alessandro Zummo <a.zummo@towertech.it>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/rtc.h>
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#define DRV_VERSION "0.3"
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/* Addresses to scan: none. This chip cannot be detected. */
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static unsigned short normal_i2c[] = { I2C_CLIENT_END };
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/* Insmod parameters */
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I2C_CLIENT_INSMOD;
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/* Registers */
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#define DS1672_REG_CNT_BASE 0
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#define DS1672_REG_CONTROL 4
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#define DS1672_REG_TRICKLE 5
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#define DS1672_REG_CONTROL_EOSC 0x80
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/* Prototypes */
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static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind);
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/*
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* In the routines that deal directly with the ds1672 hardware, we use
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* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
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* Epoch is initialized as 2000. Time is set to UTC.
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*/
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static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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unsigned long time;
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unsigned char addr = DS1672_REG_CNT_BASE;
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unsigned char buf[4];
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struct i2c_msg msgs[] = {
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{ client->addr, 0, 1, &addr }, /* setup read ptr */
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{ client->addr, I2C_M_RD, 4, buf }, /* read date */
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};
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/* read date registers */
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if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
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dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
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return -EIO;
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}
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dev_dbg(&client->dev,
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"%s: raw read data - counters=%02x,%02x,%02x,%02x\n"
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__FUNCTION__, buf[0], buf[1], buf[2], buf[3]);
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time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
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rtc_time_to_tm(time, tm);
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dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__FUNCTION__, tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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return 0;
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}
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static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
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{
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int xfer;
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unsigned char buf[6];
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buf[0] = DS1672_REG_CNT_BASE;
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buf[1] = secs & 0x000000FF;
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buf[2] = (secs & 0x0000FF00) >> 8;
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buf[3] = (secs & 0x00FF0000) >> 16;
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buf[4] = (secs & 0xFF000000) >> 24;
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buf[5] = 0; /* set control reg to enable counting */
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xfer = i2c_master_send(client, buf, 6);
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if (xfer != 6) {
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dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer);
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return -EIO;
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}
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return 0;
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}
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static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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unsigned long secs;
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dev_dbg(&client->dev,
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"%s: secs=%d, mins=%d, hours=%d, ",
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__FUNCTION__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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rtc_tm_to_time(tm, &secs);
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return ds1672_set_mmss(client, secs);
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}
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static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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return ds1672_get_datetime(to_i2c_client(dev), tm);
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}
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static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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return ds1672_set_datetime(to_i2c_client(dev), tm);
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}
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static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
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{
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return ds1672_set_mmss(to_i2c_client(dev), secs);
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}
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static int ds1672_get_control(struct i2c_client *client, u8 *status)
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{
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unsigned char addr = DS1672_REG_CONTROL;
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struct i2c_msg msgs[] = {
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{ client->addr, 0, 1, &addr }, /* setup read ptr */
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{ client->addr, I2C_M_RD, 1, status }, /* read control */
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};
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/* read control register */
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if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
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dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
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return -EIO;
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}
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return 0;
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}
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/* following are the sysfs callback functions */
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static ssize_t show_control(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct i2c_client *client = to_i2c_client(dev);
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u8 control;
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int err;
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err = ds1672_get_control(client, &control);
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if (err)
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return err;
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return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
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? "disabled" : "enabled");
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}
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static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
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static struct rtc_class_ops ds1672_rtc_ops = {
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.read_time = ds1672_rtc_read_time,
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.set_time = ds1672_rtc_set_time,
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.set_mmss = ds1672_rtc_set_mmss,
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};
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static int ds1672_attach(struct i2c_adapter *adapter)
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{
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return i2c_probe(adapter, &addr_data, ds1672_probe);
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}
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static int ds1672_detach(struct i2c_client *client)
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{
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int err;
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struct rtc_device *rtc = i2c_get_clientdata(client);
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if (rtc)
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rtc_device_unregister(rtc);
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if ((err = i2c_detach_client(client)))
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return err;
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kfree(client);
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return 0;
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}
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static struct i2c_driver ds1672_driver = {
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.driver = {
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.name = "ds1672",
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},
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.id = I2C_DRIVERID_DS1672,
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.attach_adapter = &ds1672_attach,
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.detach_client = &ds1672_detach,
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};
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static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind)
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{
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int err = 0;
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u8 control;
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struct i2c_client *client;
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struct rtc_device *rtc;
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dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
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if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
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err = -ENODEV;
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goto exit;
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}
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if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
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err = -ENOMEM;
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goto exit;
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}
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/* I2C client */
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client->addr = address;
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client->driver = &ds1672_driver;
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client->adapter = adapter;
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strlcpy(client->name, ds1672_driver.driver.name, I2C_NAME_SIZE);
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/* Inform the i2c layer */
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if ((err = i2c_attach_client(client)))
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goto exit_kfree;
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dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
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rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev,
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&ds1672_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc)) {
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err = PTR_ERR(rtc);
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goto exit_detach;
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}
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i2c_set_clientdata(client, rtc);
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/* read control register */
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err = ds1672_get_control(client, &control);
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if (err)
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goto exit_detach;
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if (control & DS1672_REG_CONTROL_EOSC)
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dev_warn(&client->dev, "Oscillator not enabled. "
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"Set time to enable.\n");
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/* Register sysfs hooks */
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device_create_file(&client->dev, &dev_attr_control);
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return 0;
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exit_detach:
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i2c_detach_client(client);
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exit_kfree:
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kfree(client);
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exit:
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return err;
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}
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static int __init ds1672_init(void)
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{
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return i2c_add_driver(&ds1672_driver);
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}
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static void __exit ds1672_exit(void)
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{
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i2c_del_driver(&ds1672_driver);
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}
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MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
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MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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module_init(ds1672_init);
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module_exit(ds1672_exit);
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