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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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257 lines
5.9 KiB
C
257 lines
5.9 KiB
C
![]() |
/*
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* Driver for Linear Technology LTC4151 High Voltage I2C Current
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* and Voltage Monitor
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*
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* Copyright (C) 2011 AppearTV AS
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*
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* Derived from:
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*
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* Driver for Linear Technology LTC4261 I2C Negative Voltage Hot
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* Swap Controller
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* Copyright (C) 2010 Ericsson AB.
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*
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* Datasheet: http://www.linear.com/docs/Datasheet/4151fc.pdf
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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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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/slab.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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/* chip registers */
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#define LTC4151_SENSE_H 0x00
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#define LTC4151_SENSE_L 0x01
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#define LTC4151_VIN_H 0x02
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#define LTC4151_VIN_L 0x03
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#define LTC4151_ADIN_H 0x04
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#define LTC4151_ADIN_L 0x05
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struct ltc4151_data {
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struct device *hwmon_dev;
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struct mutex update_lock;
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bool valid;
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unsigned long last_updated; /* in jiffies */
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/* Registers */
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u8 regs[6];
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};
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static struct ltc4151_data *ltc4151_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 ltc4151_data *data = i2c_get_clientdata(client);
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struct ltc4151_data *ret = data;
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mutex_lock(&data->update_lock);
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/*
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* The chip's A/D updates 6 times per second
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* (Conversion Rate 6 - 9 Hz)
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*/
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if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) {
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int i;
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dev_dbg(&client->dev, "Starting ltc4151 update\n");
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/* Read all registers */
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for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
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int val;
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val = i2c_smbus_read_byte_data(client, i);
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if (unlikely(val < 0)) {
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dev_dbg(dev,
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"Failed to read ADC value: error %d\n",
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val);
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ret = ERR_PTR(val);
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goto abort;
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}
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data->regs[i] = val;
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}
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data->last_updated = jiffies;
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data->valid = 1;
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}
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abort:
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mutex_unlock(&data->update_lock);
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return ret;
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}
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/* Return the voltage from the given register in mV */
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static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
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{
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u32 val;
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val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4);
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switch (reg) {
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case LTC4151_ADIN_H:
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/* 500uV resolution. Convert to mV. */
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val = val * 500 / 1000;
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break;
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case LTC4151_SENSE_H:
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/*
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* 20uV resolution. Convert to current as measured with
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* an 1 mOhm sense resistor, in mA.
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*/
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val = val * 20;
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break;
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case LTC4151_VIN_H:
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/* 25 mV per increment */
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val = val * 25;
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break;
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default:
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/* If we get here, the developer messed up */
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WARN_ON_ONCE(1);
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val = 0;
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break;
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}
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return val;
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}
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static ssize_t ltc4151_show_value(struct device *dev,
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struct device_attribute *da, char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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struct ltc4151_data *data = ltc4151_update_device(dev);
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int value;
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if (IS_ERR(data))
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return PTR_ERR(data);
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value = ltc4151_get_value(data, attr->index);
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return snprintf(buf, PAGE_SIZE, "%d\n", value);
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}
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/*
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* Input voltages.
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*/
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static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
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ltc4151_show_value, NULL, LTC4151_VIN_H);
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static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, \
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ltc4151_show_value, NULL, LTC4151_ADIN_H);
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/* Currents (via sense resistor) */
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static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
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ltc4151_show_value, NULL, LTC4151_SENSE_H);
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/* Finally, construct an array of pointers to members of the above objects,
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* as required for sysfs_create_group()
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*/
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static struct attribute *ltc4151_attributes[] = {
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&sensor_dev_attr_in1_input.dev_attr.attr,
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&sensor_dev_attr_in2_input.dev_attr.attr,
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&sensor_dev_attr_curr1_input.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ltc4151_group = {
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.attrs = ltc4151_attributes,
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};
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static int ltc4151_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct i2c_adapter *adapter = client->adapter;
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struct ltc4151_data *data;
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int ret;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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return -ENODEV;
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data = kzalloc(sizeof(*data), GFP_KERNEL);
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if (!data) {
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ret = -ENOMEM;
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goto out_kzalloc;
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}
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i2c_set_clientdata(client, data);
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mutex_init(&data->update_lock);
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/* Register sysfs hooks */
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ret = sysfs_create_group(&client->dev.kobj, <c4151_group);
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if (ret)
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goto out_sysfs_create_group;
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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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ret = PTR_ERR(data->hwmon_dev);
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goto out_hwmon_device_register;
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}
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return 0;
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out_hwmon_device_register:
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sysfs_remove_group(&client->dev.kobj, <c4151_group);
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out_sysfs_create_group:
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kfree(data);
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out_kzalloc:
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return ret;
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}
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static int ltc4151_remove(struct i2c_client *client)
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{
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struct ltc4151_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, <c4151_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 ltc4151_id[] = {
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{ "ltc4151", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ltc4151_id);
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/* This is the driver that will be inserted */
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static struct i2c_driver ltc4151_driver = {
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.driver = {
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.name = "ltc4151",
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},
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.probe = ltc4151_probe,
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.remove = ltc4151_remove,
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.id_table = ltc4151_id,
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};
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static int __init ltc4151_init(void)
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{
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return i2c_add_driver(<c4151_driver);
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}
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static void __exit ltc4151_exit(void)
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{
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i2c_del_driver(<c4151_driver);
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}
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MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
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MODULE_DESCRIPTION("LTC4151 driver");
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MODULE_LICENSE("GPL");
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module_init(ltc4151_init);
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module_exit(ltc4151_exit);
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