kernel-ark/drivers/i2c/chips/eeprom.c
Jean Delvare 7d9db67feb i2c: __must_check fixes (chip drivers)
i2c: __must_check fixes (chip drivers)

Check for error on sysfs file creation.
Delete sysfs files on device removal.

The approach taken for the most complex case (pcf8591) is similar to
what Mark M. Hoffman proposed for hardware monitoring chip drivers.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Ben Gardner <bgardner@wabtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-26 15:38:51 -07:00

260 lines
7.1 KiB
C

/*
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/sched.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);