--- a/drivers/i2c/chips/eeprom.c +++ b/drivers/i2c/chips/eeprom.c @@ -33,6 +33,8 @@ #include #include #include +#include +#include /* Addresses to scan */ static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54, @@ -41,26 +43,7 @@ static const unsigned short normal_i2c[] /* 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; -}; - +ATOMIC_NOTIFIER_HEAD(eeprom_chain); static int eeprom_attach_adapter(struct i2c_adapter *adapter); static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind); @@ -197,6 +180,7 @@ static int eeprom_detect(struct i2c_adap data->valid = 0; mutex_init(&data->update_lock); data->nature = UNKNOWN; + data->attr = &eeprom_attr; /* Tell the I2C layer a new client has arrived */ if ((err = i2c_attach_client(new_client))) @@ -224,6 +208,9 @@ static int eeprom_detect(struct i2c_adap if (err) goto exit_detach; + /* call the notifier chain */ + atomic_notifier_call_chain(&eeprom_chain, EEPROM_REGISTER, data); + return 0; exit_detach: @@ -249,6 +236,41 @@ static int eeprom_detach_client(struct i return 0; } +/** + * register_eeprom_notifier - register a 'user' of EEPROM devices. + * @nb: pointer to notifier info structure + * + * Registers a callback function to be called upon detection + * of an EEPROM device. Detection invokes the 'add' callback + * with the kobj of the mutex and a bin_attribute which allows + * read from the EEPROM. The intention is that the notifier + * will be able to read system configuration from the notifier. + * + * Only EEPROMs detected *after* the addition of the notifier + * are notified. I.e. EEPROMs already known to the system + * will not be notified - add the notifier from board level + * code! + */ +int register_eeprom_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&eeprom_chain, nb); +} + +/** + * unregister_eeprom_notifier - unregister a 'user' of EEPROM devices. + * @old: pointer to notifier info structure + * + * Removes a callback function from the list of 'users' to be + * notified upon detection of EEPROM devices. + */ +int unregister_eeprom_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(&eeprom_chain, nb); +} + +EXPORT_SYMBOL_GPL(register_eeprom_notifier); +EXPORT_SYMBOL_GPL(unregister_eeprom_notifier); + static int __init eeprom_init(void) { return i2c_add_driver(&eeprom_driver); --- /dev/null +++ b/include/linux/eeprom.h @@ -0,0 +1,71 @@ +#ifndef _LINUX_EEPROM_H +#define _LINUX_EEPROM_H +/* + * EEPROM notifier header + * + * Copyright (C) 2006 John Bowler + */ + +/* + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef __KERNEL__ +#error This is a kernel header +#endif + +#include +#include +#include + +/* 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; + struct bin_attribute *attr; +}; + +/* + * This is very basic. + * + * If an EEPROM is detected on the I2C bus (this only works for + * I2C EEPROMs) the notifier chain is called with + * both the I2C information and the kobject for the sysfs + * device which has been registers. It is then possible to + * read from the device via the bin_attribute::read method + * to extract configuration information. + * + * Register the notifier in the board level code, there is no + * need to unregister it but you can if you want (it will save + * a little bit or kernel memory to do so). + */ + +extern int register_eeprom_notifier(struct notifier_block *nb); +extern int unregister_eeprom_notifier(struct notifier_block *nb); + +#endif /* _LINUX_EEPROM_H */ --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -253,5 +253,8 @@ extern struct blocking_notifier_head reb #define VT_UPDATE 0x0004 /* A bigger update occurred */ #define VT_PREWRITE 0x0005 /* A char is about to be written to the console */ +/* eeprom notifier chain */ +#define EEPROM_REGISTER 0x0001 + #endif /* __KERNEL__ */ #endif /* _LINUX_NOTIFIER_H */