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252 lines
7.0 KiB
252 lines
7.0 KiB
/*
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eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
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monitoring
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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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2004-01-16 Jean Delvare <khali@linux-fr.org>
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Divide the eeprom in 32-byte (arbitrary) slices. This significantly
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speeds sensors up, as well as various scripts using the eeprom
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module.
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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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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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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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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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/* Addresses to scan */
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static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
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0x55, 0x56, 0x57, I2C_CLIENT_END };
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/* Insmod parameters */
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I2C_CLIENT_INSMOD_1(eeprom);
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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 i2c_client client;
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struct semaphore 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 int eeprom_attach_adapter(struct i2c_adapter *adapter);
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static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
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static int eeprom_detach_client(struct i2c_client *client);
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/* This is the driver that will be inserted */
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static struct i2c_driver eeprom_driver = {
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.owner = THIS_MODULE,
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.name = "eeprom",
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.id = I2C_DRIVERID_EEPROM,
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.flags = I2C_DF_NOTIFY,
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.attach_adapter = eeprom_attach_adapter,
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.detach_client = eeprom_detach_client,
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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, j;
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down(&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 += I2C_SMBUS_BLOCK_MAX)
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if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
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goto exit;
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} else {
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if (i2c_smbus_write_byte(client, slice << 5)) {
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dev_dbg(&client->dev, "eeprom read start has failed!\n");
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goto exit;
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}
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for (i = slice << 5; i < (slice + 1) << 5; i++) {
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j = i2c_smbus_read_byte(client);
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if (j < 0)
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goto exit;
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data->data[i] = (u8) j;
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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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up(&data->update_lock);
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}
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static ssize_t eeprom_read(struct kobject *kobj, 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 security settings to regular users (16 first bytes) */
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if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
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size_t in_row1 = 16 - off;
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in_row1 = min(in_row1, count);
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memset(buf, 0, in_row1);
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if (count - in_row1 > 0)
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memcpy(buf + in_row1, &data->data[16], count - in_row1);
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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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.owner = THIS_MODULE,
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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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static int eeprom_attach_adapter(struct i2c_adapter *adapter)
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{
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return i2c_probe(adapter, &addr_data, eeprom_detect);
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}
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/* This function is called by i2c_probe */
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static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
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{
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struct i2c_client *new_client;
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struct eeprom_data *data;
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int err = 0;
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/* There are three 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) Consecutive byte reads (100% overhead)
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(3) Regular byte data reads (200% overhead)
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The third method is not implemented by this driver because all
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known adapters support at least the second. */
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
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| I2C_FUNC_SMBUS_BYTE))
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goto exit;
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if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
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err = -ENOMEM;
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goto exit;
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}
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new_client = &data->client;
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memset(data->data, 0xff, EEPROM_SIZE);
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i2c_set_clientdata(new_client, data);
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new_client->addr = address;
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new_client->adapter = adapter;
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new_client->driver = &eeprom_driver;
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new_client->flags = 0;
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/* Fill in the remaining client fields */
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strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
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data->valid = 0;
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init_MUTEX(&data->update_lock);
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data->nature = UNKNOWN;
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/* Tell the I2C layer a new client has arrived */
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if ((err = i2c_attach_client(new_client)))
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goto exit_kfree;
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/* Detect the Vaio nature of EEPROMs.
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We use the "PCG-" prefix as the signature. */
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if (address == 0x57) {
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if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
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&& i2c_smbus_read_byte(new_client) == 'C'
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&& i2c_smbus_read_byte(new_client) == 'G'
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&& i2c_smbus_read_byte(new_client) == '-') {
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dev_info(&new_client->dev, "Vaio EEPROM detected, "
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"enabling password 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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sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
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return 0;
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exit_kfree:
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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 eeprom_detach_client(struct i2c_client *client)
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{
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int err;
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err = i2c_detach_client(client);
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if (err)
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return err;
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kfree(i2c_get_clientdata(client));
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return 0;
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}
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static int __init eeprom_init(void)
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{
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return i2c_add_driver(&eeprom_driver);
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}
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static void __exit eeprom_exit(void)
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{
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i2c_del_driver(&eeprom_driver);
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}
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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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module_init(eeprom_init);
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module_exit(eeprom_exit);
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