269 lines
		
	
	
		
			7.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			269 lines
		
	
	
		
			7.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * An hwmon driver for the Analog Devices AD7414
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 *
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 * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
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 *
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 * Copyright (c) 2008 PIKA Technologies
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 *   Sean MacLennan <smaclennan@pikatech.com>
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 *
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 * Copyright (c) 2008 Spansion Inc.
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 *   Frank Edelhaeuser <frank.edelhaeuser at spansion.com>
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 *   (converted to "new style" I2C driver model, removed checkpatch.pl warnings)
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 *
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 * Based on ad7418.c
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 * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at 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 as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 */
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#include <linux/module.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/sysfs.h>
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/* AD7414 registers */
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#define AD7414_REG_TEMP		0x00
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#define AD7414_REG_CONF		0x01
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#define AD7414_REG_T_HIGH	0x02
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#define AD7414_REG_T_LOW	0x03
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static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };
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struct ad7414_data {
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	struct device		*hwmon_dev;
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	struct mutex		lock;	/* atomic read data updates */
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	char			valid;	/* !=0 if following fields are valid */
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	unsigned long		next_update;	/* In jiffies */
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	s16			temp_input;	/* Register values */
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	s8			temps[ARRAY_SIZE(AD7414_REG_LIMIT)];
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};
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/* REG: (0.25C/bit, two's complement) << 6 */
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static inline int ad7414_temp_from_reg(s16 reg)
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{
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	/* use integer division instead of equivalent right shift to
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	 * guarantee arithmetic shift and preserve the sign
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	 */
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	return ((int)reg / 64) * 250;
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}
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static inline int ad7414_read(struct i2c_client *client, u8 reg)
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{
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	if (reg == AD7414_REG_TEMP) {
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		int value = i2c_smbus_read_word_data(client, reg);
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		return (value < 0) ? value : swab16(value);
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	} else
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		return i2c_smbus_read_byte_data(client, reg);
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}
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static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
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{
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	return i2c_smbus_write_byte_data(client, reg, value);
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}
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static struct ad7414_data *ad7414_update_device(struct device *dev)
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{
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	struct i2c_client *client = to_i2c_client(dev);
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	struct ad7414_data *data = i2c_get_clientdata(client);
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	mutex_lock(&data->lock);
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	if (time_after(jiffies, data->next_update) || !data->valid) {
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		int value, i;
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		dev_dbg(&client->dev, "starting ad7414 update\n");
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		value = ad7414_read(client, AD7414_REG_TEMP);
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		if (value < 0)
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			dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
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				value);
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		else
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			data->temp_input = value;
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		for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
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			value = ad7414_read(client, AD7414_REG_LIMIT[i]);
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			if (value < 0)
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				dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
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					AD7414_REG_LIMIT[i], value);
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			else
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				data->temps[i] = value;
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		}
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		data->next_update = jiffies + HZ + HZ / 2;
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		data->valid = 1;
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	}
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	mutex_unlock(&data->lock);
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	return data;
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}
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static ssize_t show_temp_input(struct device *dev,
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			       struct device_attribute *attr, char *buf)
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{
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	struct ad7414_data *data = ad7414_update_device(dev);
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	return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
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}
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
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static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
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			  char *buf)
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{
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	int index = to_sensor_dev_attr(attr)->index;
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	struct ad7414_data *data = ad7414_update_device(dev);
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	return sprintf(buf, "%d\n", data->temps[index] * 1000);
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}
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static ssize_t set_max_min(struct device *dev,
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			   struct device_attribute *attr,
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			   const char *buf, size_t count)
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{
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	struct i2c_client *client = to_i2c_client(dev);
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	struct ad7414_data *data = i2c_get_clientdata(client);
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	int index = to_sensor_dev_attr(attr)->index;
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	u8 reg = AD7414_REG_LIMIT[index];
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	long temp = simple_strtol(buf, NULL, 10);
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	temp = SENSORS_LIMIT(temp, -40000, 85000);
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	temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
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	mutex_lock(&data->lock);
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	data->temps[index] = temp;
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	ad7414_write(client, reg, temp);
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	mutex_unlock(&data->lock);
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	return count;
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}
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static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
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			  show_max_min, set_max_min, 0);
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static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
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			  show_max_min, set_max_min, 1);
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static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
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			  char *buf)
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{
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	int bitnr = to_sensor_dev_attr(attr)->index;
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	struct ad7414_data *data = ad7414_update_device(dev);
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	int value = (data->temp_input >> bitnr) & 1;
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	return sprintf(buf, "%d\n", value);
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}
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static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
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static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
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static struct attribute *ad7414_attributes[] = {
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	&sensor_dev_attr_temp1_input.dev_attr.attr,
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	&sensor_dev_attr_temp1_max.dev_attr.attr,
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	&sensor_dev_attr_temp1_min.dev_attr.attr,
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	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
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	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
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	NULL
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};
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static const struct attribute_group ad7414_group = {
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	.attrs = ad7414_attributes,
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};
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static int ad7414_probe(struct i2c_client *client,
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			const struct i2c_device_id *dev_id)
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{
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	struct ad7414_data *data;
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	int conf;
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	int err = 0;
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	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
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				     I2C_FUNC_SMBUS_READ_WORD_DATA))
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		goto exit;
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	data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL);
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	if (!data) {
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		err = -ENOMEM;
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		goto exit;
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	}
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	i2c_set_clientdata(client, data);
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	mutex_init(&data->lock);
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	dev_info(&client->dev, "chip found\n");
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	/* Make sure the chip is powered up. */
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	conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
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	if (conf < 0)
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		dev_warn(&client->dev,
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			 "ad7414_probe unable to read config register.\n");
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	else {
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		conf &= ~(1 << 7);
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		i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
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	}
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	/* Register sysfs hooks */
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	err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
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	if (err)
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		goto exit_free;
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	data->hwmon_dev = hwmon_device_register(&client->dev);
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	if (IS_ERR(data->hwmon_dev)) {
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		err = PTR_ERR(data->hwmon_dev);
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		goto exit_remove;
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	}
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	return 0;
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exit_remove:
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	sysfs_remove_group(&client->dev.kobj, &ad7414_group);
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exit_free:
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	kfree(data);
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exit:
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	return err;
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}
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static int __devexit ad7414_remove(struct i2c_client *client)
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{
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	struct ad7414_data *data = i2c_get_clientdata(client);
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	hwmon_device_unregister(data->hwmon_dev);
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	sysfs_remove_group(&client->dev.kobj, &ad7414_group);
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	kfree(data);
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	return 0;
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}
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static const struct i2c_device_id ad7414_id[] = {
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	{ "ad7414", 0 },
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	{}
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};
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static struct i2c_driver ad7414_driver = {
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	.driver = {
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		.name	= "ad7414",
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	},
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	.probe	= ad7414_probe,
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	.remove	= __devexit_p(ad7414_remove),
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	.id_table = ad7414_id,
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};
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static int __init ad7414_init(void)
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{
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	return i2c_add_driver(&ad7414_driver);
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}
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module_init(ad7414_init);
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static void __exit ad7414_exit(void)
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{
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	i2c_del_driver(&ad7414_driver);
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}
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module_exit(ad7414_exit);
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MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
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	      "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
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MODULE_DESCRIPTION("AD7414 driver");
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MODULE_LICENSE("GPL");
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