drivers/i2c/chips/eeprom.c - kernel/msm-4.9 - Gitiles

 /*
     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 <khali@linux-fr.org>

     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/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 };

 /* 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",
 	},
 	.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;

 	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 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,
 };

 static int eeprom_attach_adapter(struct i2c_adapter *adapter)
 {
 	if (!(adapter->class & (I2C_CLASS_DDC | I2C_CLASS_SPD)))
 		return 0;
 	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 *client;
 	struct eeprom_data *data;
 	int err = 0;

 	/* 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) && address >= 0x51)
 		goto exit;

 	/* 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))
 		goto exit;

 	if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
 		err = -ENOMEM;
 		goto exit;
 	}

 	client = &data->client;
 	memset(data->data, 0xff, EEPROM_SIZE);
 	i2c_set_clientdata(client, data);
 	client->addr = address;
 	client->adapter = adapter;
 	client->driver = &eeprom_driver;

 	/* Fill in the remaining client fields */
 	strlcpy(client->name, "eeprom", I2C_NAME_SIZE);
 	mutex_init(&data->update_lock);
 	data->nature = UNKNOWN;

 	/* Tell the I2C layer a new client has arrived */
 	if ((err = i2c_attach_client(client)))
 		goto exit_kfree;

 	/* Detect the Vaio nature of EEPROMs.
 	   We use the "PCG-" or "VGN-" prefix as the signature. */
 	if (address == 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_detach;

 	return 0;

 exit_detach:
 	i2c_detach_client(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);
	/*
	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 <khali@linux-fr.org>

	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/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 };

	/* 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",
	},
	.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;

	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 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,
	};

	static int eeprom_attach_adapter(struct i2c_adapter *adapter)
	{
	if (!(adapter->class & (I2C_CLASS_DDC \| I2C_CLASS_SPD)))
	return 0;
	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 *client;
	struct eeprom_data *data;
	int err = 0;

	/* 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) && address >= 0x51)
	goto exit;

	/* 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))
	goto exit;

	if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
	err = -ENOMEM;
	goto exit;
	}

	client = &data->client;
	memset(data->data, 0xff, EEPROM_SIZE);
	i2c_set_clientdata(client, data);
	client->addr = address;
	client->adapter = adapter;
	client->driver = &eeprom_driver;

	/* Fill in the remaining client fields */
	strlcpy(client->name, "eeprom", I2C_NAME_SIZE);
	mutex_init(&data->update_lock);
	data->nature = UNKNOWN;

	/* Tell the I2C layer a new client has arrived */
	if ((err = i2c_attach_client(client)))
	goto exit_kfree;

	/* Detect the Vaio nature of EEPROMs.
	We use the "PCG-" or "VGN-" prefix as the signature. */
	if (address == 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_detach;

	return 0;

	exit_detach:
	i2c_detach_client(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);