Initial import

1 files changed, 226 insertions, 0 deletions

diff --git a/drivers/misc/eeprom/eeprom.c b/drivers/misc/eeprom/eeprom.c
new file mode 100644
index 000000000..b432873de
--- /dev/null
+++ b/drivers/misc/eeprom/eeprom.c
@@ -0,0 +1,226 @@
+/*
+ * 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");