/* * Copyright (C) 1998, 1999 Frodo Looijaard and * Philip Edelbrock * Copyright (C) 2003 Greg Kroah-Hartman * Copyright (C) 2003 IBM Corp. * Copyright (C) 2004 Jean Delvare * * 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. */ #include #include #include #include #include #include #include /* Addresses to scan */ static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, I2C_CLIENT_END }; /* 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 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 void eeprom_update_client(struct i2c_client *client, u8 slice) { struct eeprom_data *data = i2c_get_clientdata(client); int i; 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 += 32) if (i2c_smbus_read_i2c_block_data(client, i, 32, data->data + i) != 32) goto exit; } else { for (i = slice << 5; i < (slice + 1) << 5; i += 2) { int word = i2c_smbus_read_word_data(client, i); if (word < 0) goto exit; data->data[i] = word & 0xff; data->data[i + 1] = word >> 8; } } data->last_updated[slice] = jiffies; data->valid |= (1 << slice); } exit: mutex_unlock(&data->update_lock); } static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, 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 private settings to regular users: - BIOS passwords: bytes 0x00 to 0x0f - UUID: bytes 0x10 to 0x1f - Serial number: 0xc0 to 0xdf */ if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) { int i; for (i = 0; i < count; i++) { if ((off + i <= 0x1f) || (off + i >= 0xc0 && off + i <= 0xdf)) buf[i] = 0; else buf[i] = data->data[off + i]; } } else { memcpy(buf, &data->data[off], count); } return count; } static struct bin_attribute eeprom_attr = { .attr = { .name = "eeprom", .mode = S_IRUGO, }, .size = EEPROM_SIZE, .read = eeprom_read, }; /* Return 0 if detection is successful, -ENODEV otherwise */ static int eeprom_detect(struct i2c_client *client, struct i2c_board_info *info) { struct i2c_adapter *adapter = client->adapter; /* EDID EEPROMs are often 24C00 EEPROMs, which answer to all addresses 0x50-0x57, but we only care about 0x50. So decline attaching to addresses >= 0x51 on DDC buses */ if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51) return -ENODEV; /* There are four ways we can read the EEPROM data: (1) I2C block reads (faster, but unsupported by most adapters) (2) Word reads (128% overhead) (3) Consecutive byte reads (88% overhead, unsafe) (4) Regular byte data reads (265% overhead) The third and fourth methods are not implemented by this driver because all known adapters support one of the first two. */ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA) && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) return -ENODEV; strlcpy(info->type, "eeprom", I2C_NAME_SIZE); return 0; } static int eeprom_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct i2c_adapter *adapter = client->adapter; struct eeprom_data *data; int err; if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) { err = -ENOMEM; goto exit; } memset(data->data, 0xff, EEPROM_SIZE); i2c_set_clientdata(client, data); mutex_init(&data->update_lock); data->nature = UNKNOWN; /* Detect the Vaio nature of EEPROMs. We use the "PCG-" or "VGN-" prefix as the signature. */ if (client->addr == 0x57 && i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) { char name[4]; name[0] = i2c_smbus_read_byte_data(client, 0x80); name[1] = i2c_smbus_read_byte_data(client, 0x81); name[2] = i2c_smbus_read_byte_data(client, 0x82); name[3] = i2c_smbus_read_byte_data(client, 0x83); if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) { dev_info(&client->dev, "Vaio EEPROM detected, " "enabling privacy protection\n"); data->nature = VAIO; } } /* create the sysfs eeprom file */ err = sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr); if (err) goto exit_kfree; return 0; exit_kfree: kfree(data); exit: return err; } static int eeprom_remove(struct i2c_client *client) { sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr); kfree(i2c_get_clientdata(client)); return 0; } static const struct i2c_device_id eeprom_id[] = { { "eeprom", 0 }, { } }; static struct i2c_driver eeprom_driver = { .driver = { .name = "eeprom", }, .probe = eeprom_probe, .remove = eeprom_remove, .id_table = eeprom_id, .class = I2C_CLASS_DDC | I2C_CLASS_SPD, .detect = eeprom_detect, .address_list = normal_i2c, }; 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 and " "Philip Edelbrock and " "Greg Kroah-Hartman "); MODULE_DESCRIPTION("I2C EEPROM driver"); MODULE_LICENSE("GPL"); module_init(eeprom_init); module_exit(eeprom_exit);