227 lines
6.4 KiB
C
227 lines
6.4 KiB
C
/*
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* Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
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* Philip Edelbrock <phil@netroedge.com>
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* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
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* Copyright (C) 2003 IBM Corp.
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* Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
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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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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/mutex.h>
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/* Addresses to scan */
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static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
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0x55, 0x56, 0x57, I2C_CLIENT_END };
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/* Size of EEPROM in bytes */
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#define EEPROM_SIZE 256
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/* possible types of eeprom devices */
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enum eeprom_nature {
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UNKNOWN,
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VAIO,
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};
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/* Each client has this additional data */
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struct eeprom_data {
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struct mutex update_lock;
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u8 valid; /* bitfield, bit!=0 if slice is valid */
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unsigned long last_updated[8]; /* In jiffies, 8 slices */
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u8 data[EEPROM_SIZE]; /* Register values */
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enum eeprom_nature nature;
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};
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static void eeprom_update_client(struct i2c_client *client, u8 slice)
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{
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struct eeprom_data *data = i2c_get_clientdata(client);
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int i;
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mutex_lock(&data->update_lock);
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if (!(data->valid & (1 << slice)) ||
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time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
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dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
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if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
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for (i = slice << 5; i < (slice + 1) << 5; i += 32)
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if (i2c_smbus_read_i2c_block_data(client, i,
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32, data->data + i)
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!= 32)
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goto exit;
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} else {
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for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
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int word = i2c_smbus_read_word_data(client, i);
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if (word < 0)
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goto exit;
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data->data[i] = word & 0xff;
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data->data[i + 1] = word >> 8;
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}
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}
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data->last_updated[slice] = jiffies;
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data->valid |= (1 << slice);
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}
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exit:
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mutex_unlock(&data->update_lock);
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}
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static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr,
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char *buf, loff_t off, size_t count)
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{
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struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
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struct eeprom_data *data = i2c_get_clientdata(client);
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u8 slice;
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if (off > EEPROM_SIZE)
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return 0;
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if (off + count > EEPROM_SIZE)
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count = EEPROM_SIZE - off;
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/* Only refresh slices which contain requested bytes */
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for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
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eeprom_update_client(client, slice);
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/* Hide Vaio private settings to regular users:
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- BIOS passwords: bytes 0x00 to 0x0f
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- UUID: bytes 0x10 to 0x1f
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- Serial number: 0xc0 to 0xdf */
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if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
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int i;
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for (i = 0; i < count; i++) {
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if ((off + i <= 0x1f) ||
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(off + i >= 0xc0 && off + i <= 0xdf))
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buf[i] = 0;
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else
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buf[i] = data->data[off + i];
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}
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} else {
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memcpy(buf, &data->data[off], count);
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}
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return count;
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}
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static struct bin_attribute eeprom_attr = {
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.attr = {
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.name = "eeprom",
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.mode = S_IRUGO,
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},
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.size = EEPROM_SIZE,
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.read = eeprom_read,
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};
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/* Return 0 if detection is successful, -ENODEV otherwise */
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static int eeprom_detect(struct i2c_client *client, struct i2c_board_info *info)
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{
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struct i2c_adapter *adapter = client->adapter;
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/* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
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addresses 0x50-0x57, but we only care about 0x50. So decline
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attaching to addresses >= 0x51 on DDC buses */
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if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51)
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return -ENODEV;
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/* There are four ways we can read the EEPROM data:
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(1) I2C block reads (faster, but unsupported by most adapters)
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(2) Word reads (128% overhead)
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(3) Consecutive byte reads (88% overhead, unsafe)
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(4) Regular byte data reads (265% overhead)
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The third and fourth methods are not implemented by this driver
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because all known adapters support one of the first two. */
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
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&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
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return -ENODEV;
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strlcpy(info->type, "eeprom", I2C_NAME_SIZE);
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return 0;
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}
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static int eeprom_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 eeprom_data *data;
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data = devm_kzalloc(&client->dev, sizeof(struct eeprom_data),
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GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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memset(data->data, 0xff, EEPROM_SIZE);
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i2c_set_clientdata(client, data);
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mutex_init(&data->update_lock);
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data->nature = UNKNOWN;
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/* Detect the Vaio nature of EEPROMs.
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We use the "PCG-" or "VGN-" prefix as the signature. */
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if (client->addr == 0x57
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&& i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
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char name[4];
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name[0] = i2c_smbus_read_byte_data(client, 0x80);
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name[1] = i2c_smbus_read_byte_data(client, 0x81);
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name[2] = i2c_smbus_read_byte_data(client, 0x82);
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name[3] = i2c_smbus_read_byte_data(client, 0x83);
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if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
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dev_info(&client->dev, "Vaio EEPROM detected, "
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"enabling privacy protection\n");
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data->nature = VAIO;
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}
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}
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/* create the sysfs eeprom file */
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return sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
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}
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static int eeprom_remove(struct i2c_client *client)
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{
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sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
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return 0;
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}
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static const struct i2c_device_id eeprom_id[] = {
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{ "eeprom", 0 },
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{ }
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};
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static struct i2c_driver eeprom_driver = {
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.driver = {
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.name = "eeprom",
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},
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.probe = eeprom_probe,
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.remove = eeprom_remove,
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.id_table = eeprom_id,
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.class = I2C_CLASS_DDC | I2C_CLASS_SPD,
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.detect = eeprom_detect,
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.address_list = normal_i2c,
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};
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module_i2c_driver(eeprom_driver);
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MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
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"Philip Edelbrock <phil@netroedge.com> and "
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"Greg Kroah-Hartman <greg@kroah.com>");
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MODULE_DESCRIPTION("I2C EEPROM driver");
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MODULE_LICENSE("GPL");
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