drivers/i2c/chips/eeprom.c - kernel/msm-4.19 - Gitiles

 /*
     eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
                monitoring
     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.

     2004-01-16  Jean Delvare <khali@linux-fr.org>
     Divide the eeprom in 32-byte (arbitrary) slices. This significantly
     speeds sensors up, as well as various scripts using the eeprom
     module.

     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 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",
 	},
 	.id		= I2C_DRIVERID_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, j;

 	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 += I2C_SMBUS_BLOCK_MAX)
 				if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
 					goto exit;
 		} else {
 			if (i2c_smbus_write_byte(client, slice << 5)) {
 				dev_dbg(&client->dev, "eeprom read start has failed!\n");
 				goto exit;
 			}
 			for (i = slice << 5; i < (slice + 1) << 5; i++) {
 				j = i2c_smbus_read_byte(client);
 				if (j < 0)
 					goto exit;
 				data->data[i] = (u8) j;
 			}
 		}
 		data->last_updated[slice] = jiffies;
 		data->valid |= (1 << slice);
 	}
 exit:
 	mutex_unlock(&data->update_lock);
 }

 static ssize_t eeprom_read(struct kobject *kobj, 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 security settings to regular users (16 first bytes) */
 	if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
 		size_t in_row1 = 16 - off;
 		in_row1 = min(in_row1, count);
 		memset(buf, 0, in_row1);
 		if (count - in_row1 > 0)
 			memcpy(buf + in_row1, &data->data[16], count - in_row1);
 	} else {
 		memcpy(buf, &data->data[off], count);
 	}

 	return count;
 }

 static struct bin_attribute eeprom_attr = {
 	.attr = {
 		.name = "eeprom",
 		.mode = S_IRUGO,
 		.owner = THIS_MODULE,
 	},
 	.size = EEPROM_SIZE,
 	.read = eeprom_read,
 };

 static int eeprom_attach_adapter(struct i2c_adapter *adapter)
 {
 	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 *new_client;
 	struct eeprom_data *data;
 	int err = 0;

 	/* There are three ways we can read the EEPROM data:
 	   (1) I2C block reads (faster, but unsupported by most adapters)
 	   (2) Consecutive byte reads (100% overhead)
 	   (3) Regular byte data reads (200% overhead)
 	   The third method is not implemented by this driver because all
 	   known adapters support at least the second. */
 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
 					    | I2C_FUNC_SMBUS_BYTE))
 		goto exit;

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

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

 	/* Fill in the remaining client fields */
 	strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
 	data->valid = 0;
 	mutex_init(&data->update_lock);
 	data->nature = UNKNOWN;

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

 	/* Detect the Vaio nature of EEPROMs.
 	   We use the "PCG-" prefix as the signature. */
 	if (address == 0x57) {
 		if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
 		 && i2c_smbus_read_byte(new_client) == 'C'
 		 && i2c_smbus_read_byte(new_client) == 'G'
 		 && i2c_smbus_read_byte(new_client) == '-') {
 			dev_info(&new_client->dev, "Vaio EEPROM detected, "
 				"enabling password protection\n");
 			data->nature = VAIO;
 		}
 	}

 	/* create the sysfs eeprom file */
 	err = sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
 	if (err)
 		goto exit_detach;

 	return 0;

 exit_detach:
 	i2c_detach_client(new_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);
	/*
	eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
	monitoring
	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.

	2004-01-16 Jean Delvare <khali@linux-fr.org>
	Divide the eeprom in 32-byte (arbitrary) slices. This significantly
	speeds sensors up, as well as various scripts using the eeprom
	module.

	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 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",
	},
	.id = I2C_DRIVERID_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, j;

	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 += I2C_SMBUS_BLOCK_MAX)
	if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
	goto exit;
	} else {
	if (i2c_smbus_write_byte(client, slice << 5)) {
	dev_dbg(&client->dev, "eeprom read start has failed!\n");
	goto exit;
	}
	for (i = slice << 5; i < (slice + 1) << 5; i++) {
	j = i2c_smbus_read_byte(client);
	if (j < 0)
	goto exit;
	data->data[i] = (u8) j;
	}
	}
	data->last_updated[slice] = jiffies;
	data->valid \|= (1 << slice);
	}
	exit:
	mutex_unlock(&data->update_lock);
	}

	static ssize_t eeprom_read(struct kobject kobj, 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 security settings to regular users (16 first bytes) */
	if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
	size_t in_row1 = 16 - off;
	in_row1 = min(in_row1, count);
	memset(buf, 0, in_row1);
	if (count - in_row1 > 0)
	memcpy(buf + in_row1, &data->data[16], count - in_row1);
	} else {
	memcpy(buf, &data->data[off], count);
	}

	return count;
	}

	static struct bin_attribute eeprom_attr = {
	.attr = {
	.name = "eeprom",
	.mode = S_IRUGO,
	.owner = THIS_MODULE,
	},
	.size = EEPROM_SIZE,
	.read = eeprom_read,
	};

	static int eeprom_attach_adapter(struct i2c_adapter *adapter)
	{
	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 *new_client;
	struct eeprom_data *data;
	int err = 0;

	/* There are three ways we can read the EEPROM data:
	(1) I2C block reads (faster, but unsupported by most adapters)
	(2) Consecutive byte reads (100% overhead)
	(3) Regular byte data reads (200% overhead)
	The third method is not implemented by this driver because all
	known adapters support at least the second. */
	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
	\| I2C_FUNC_SMBUS_BYTE))
	goto exit;

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

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

	/* Fill in the remaining client fields */
	strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
	data->valid = 0;
	mutex_init(&data->update_lock);
	data->nature = UNKNOWN;

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

	/* Detect the Vaio nature of EEPROMs.
	We use the "PCG-" prefix as the signature. */
	if (address == 0x57) {
	if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
	&& i2c_smbus_read_byte(new_client) == 'C'
	&& i2c_smbus_read_byte(new_client) == 'G'
	&& i2c_smbus_read_byte(new_client) == '-') {
	dev_info(&new_client->dev, "Vaio EEPROM detected, "
	"enabling password protection\n");
	data->nature = VAIO;
	}
	}

	/* create the sysfs eeprom file */
	err = sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
	if (err)
	goto exit_detach;

	return 0;

	exit_detach:
	i2c_detach_client(new_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);