root/trunk/patches/2.6.22/14-eeprom-new-notifier.patch

drivers/i2c/chips/eeprom.c

@@ -33 +33 @@
 #include <linux/jiffies.h>
 #include <linux/i2c.h>
 #include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/eeprom.h>
 
 /* Addresses to scan */
 static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
@@ -41 +43 @@
 /* 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);
@@ -189 +172 @@
         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)))
@@ -212 +196 @@
         if (err)
                 goto exit_detach;
 
+        /* call the notifier chain */
+        atomic_notifier_call_chain(&eeprom_chain, EEPROM_REGISTER, data);
+
         return 0;
 
 exit_detach:
@@ -237 +224 @@
         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);

(a) /dev/null vs. (b) linux-2.6.22-rc1-arm/include/linux/eeprom.h

@@ +1 @@
+#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 <linux/list.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+
+/* 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 */

include/linux/notifier.h

@@ -209 +209 @@
 #define CPU_DOWN_FAILED_FROZEN  (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
 #define CPU_DEAD_FROZEN         (CPU_DEAD | CPU_TASKS_FROZEN)
 
+/* eeprom notifier chain */
+#define EEPROM_REGISTER         0x0001
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_NOTIFIER_H */