--- /dev/null
+/*
+ * 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.
+ * Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
+ *
+ * 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 <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+
+/* 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;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct eeprom_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ 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 */
+ return sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
+}
+
+static int eeprom_remove(struct i2c_client *client)
+{
+ sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
+
+ 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,
+};
+
+module_i2c_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");
Code Review / kvmfornfv.git / blobdiff