/*
eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
monitoring
Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
Philip Edelbrock <phil@netroedge.com>
Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
Copyright (C) 2003 IBM Corp.
2004-01-16 Jean Delvare <khali@linux-fr.org>
Divide the eeprom in 32-byte (arbitrary) slices. This significantly
speeds sensors up, as well as various scripts using the eeprom
module.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
0x55, 0x56, 0x57, I2C_CLIENT_END };
/* Insmod parameters */
I2C_CLIENT_INSMOD_1(eeprom);
/* Size of EEPROM in bytes */
#define EEPROM_SIZE 256
/* possible types of eeprom devices */
enum eeprom_nature {
UNKNOWN,
VAIO,
};
/* Each client has this additional data */
struct eeprom_data {
struct i2c_client client;
struct mutex update_lock;
u8 valid; /* bitfield, bit!=0 if slice is valid */
unsigned long last_updated[8]; /* In jiffies, 8 slices */
u8 data[EEPROM_SIZE]; /* Register values */
enum eeprom_nature nature;
};
static int eeprom_attach_adapter(struct i2c_adapter *adapter);
static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
static int eeprom_detach_client(struct i2c_client *client);
/* This is the driver that will be inserted */
static struct i2c_driver eeprom_driver = {
.driver = {
.name = "eeprom",
},
.id = I2C_DRIVERID_EEPROM,
.attach_adapter = eeprom_attach_adapter,
.detach_client = eeprom_detach_client,
};
static void eeprom_update_client(struct i2c_client *client, u8 slice)
{
struct eeprom_data *data = i2c_get_clientdata(client);
int i, j;
mutex_lock(&data->update_lock);
if (!(data->valid & (1 << slice)) ||
time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_BLOCK_MAX)
if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
goto exit;
} else {
if (i2c_smbus_write_byte(client, slice << 5)) {
dev_dbg(&client->dev, "eeprom read start has failed!\n");
goto exit;
}
for (i = slice << 5; i < (slice + 1) << 5; i++) {
j = i2c_smbus_read_byte(client);
if (j < 0)
goto exit;
data->data[i] = (u8) j;
}
}
data->last_updated[slice] = jiffies;
data->valid |= (1 << slice);
}
exit:
mutex_unlock(&data->update_lock);
}
static ssize_t eeprom_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
{
struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
struct eeprom_data *data = i2c_get_clientdata(client);
u8 slice;
if (off > EEPROM_SIZE)
return 0;
if (off + count > EEPROM_SIZE)
count = EEPROM_SIZE - off;
/* Only refresh slices which contain requested bytes */
for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
eeprom_update_client(client, slice);
/* Hide Vaio security settings to regular users (16 first bytes) */
if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
size_t in_row1 = 16 - off;
in_row1 = min(in_row1, count);
memset(buf, 0, in_row1);
if (count - in_row1 > 0)
memcpy(buf + in_row1, &data->data[16], count - in_row1);
} else {
memcpy(buf, &data->data[off], count);
}
return count;
}
static struct bin_attribute eeprom_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO,
.owner = THIS_MODULE,
},
.size = EEPROM_SIZE,
.read = eeprom_read,
};
static int eeprom_attach_adapter(struct i2c_adapter *adapter)
{
return i2c_probe(adapter, &addr_data, eeprom_detect);
}
/* This function is called by i2c_probe */
static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
{
struct i2c_client *new_client;
struct eeprom_data *data;
int err = 0;
/* There are three ways we can read the EEPROM data:
(1) I2C block reads (faster, but unsupported by most adapters)
(2) Consecutive byte reads (100% overhead)
(3) Regular byte data reads (200% overhead)
The third method is not implemented by this driver because all
known adapters support at least the second. */
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
| I2C_FUNC_SMBUS_BYTE))
goto exit;
if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
new_client = &data->client;
memset(data->data, 0xff, EEPROM_SIZE);
i2c_set_clientdata(new_client, data);
new_client->addr = address;
new_client->adapter = adapter;
new_client->driver = &eeprom_driver;
new_client->flags = 0;
/* Fill in the remaining client fields */
strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
data->valid = 0;
mutex_init(&data->update_lock);
data->nature = UNKNOWN;
/* Tell the I2C layer a new client has arrived */
if ((err = i2c_attach_client(new_client)))
goto exit_kfree;
/* Detect the Vaio nature of EEPROMs.
We use the "PCG-" prefix as the signature. */
if (address == 0x57) {
if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
&& i2c_smbus_read_byte(new_client) == 'C'
&& i2c_smbus_read_byte(new_client) == 'G'
&& i2c_smbus_read_byte(new_client) == '-') {
dev_info(&new_client->dev, "Vaio EEPROM detected, "
"enabling password protection\n");
data->nature = VAIO;
}
}
/* create the sysfs eeprom file */
err = sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
if (err)
goto exit_detach;
return 0;
exit_detach:
i2c_detach_client(new_client);
exit_kfree:
kfree(data);
exit:
return err;
}
static int eeprom_detach_client(struct i2c_client *client)
{
int err;
sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
err = i2c_detach_client(client);
if (err)
return err;
kfree(i2c_get_clientdata(client));
return 0;
}
static int __init eeprom_init(void)
{
return i2c_add_driver(&eeprom_driver);
}
static void __exit eeprom_exit(void)
{
i2c_del_driver(&eeprom_driver);
}
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
"Philip Edelbrock <phil@netroedge.com> and "
"Greg Kroah-Hartman <greg@kroah.com>");
MODULE_DESCRIPTION("I2C EEPROM driver");
MODULE_LICENSE("GPL");
module_init(eeprom_init);
module_exit(eeprom_exit);
