target/linux/ixp4xx-2.6/patches/800-eeprom_new_notifier.patch

   1 Add EEPROM notifiers
   2
   3 These help board level code by allowing a callback when EEPROMs are
   4 loaded, this permits system level configuration to be loaded from the
   5 EEPROM.  This is particularly useful when the ethernet MAC ids are
   6 stored in EEPROM and when the ethernet hardware is generic (so it
   7 has no board level knowledge), then the MACs can be loaded into
   8 the 'maclist' code and read out by the ethernet config.
   9
  10 Signed-off-by: John Bowler <jbowler@acm.org>
  11
  12 Index: linux-2.6.21-rc1-arm/drivers/i2c/chips/eeprom.c
  13 ===================================================================
  14 --- linux-2.6.21-rc1-arm.orig/drivers/i2c/chips/eeprom.c        2007-02-21 02:24:14.000000000 -0800
  15 +++ linux-2.6.21-rc1-arm/drivers/i2c/chips/eeprom.c     2007-02-21 02:25:01.000000000 -0800
  16 @@ -33,6 +33,8 @@
  17  #include <linux/jiffies.h>
  18  #include <linux/i2c.h>
  19  #include <linux/mutex.h>
  20 +#include <linux/notifier.h>
  21 +#include <linux/eeprom.h>
  22
  23  /* Addresses to scan */
  24  static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
  25 @@ -41,26 +43,7 @@
  26  /* Insmod parameters */
  27  I2C_CLIENT_INSMOD_1(eeprom);
  28
  29 -
  30 -/* Size of EEPROM in bytes */
  31 -#define EEPROM_SIZE            256
  32 -
  33 -/* possible types of eeprom devices */
  34 -enum eeprom_nature {
  35 -       UNKNOWN,
  36 -       VAIO,
  37 -};
  38 -
  39 -/* Each client has this additional data */
  40 -struct eeprom_data {
  41 -       struct i2c_client client;
  42 -       struct mutex update_lock;
  43 -       u8 valid;                       /* bitfield, bit!=0 if slice is valid */
  44 -       unsigned long last_updated[8];  /* In jiffies, 8 slices */
  45 -       u8 data[EEPROM_SIZE];           /* Register values */
  46 -       enum eeprom_nature nature;
  47 -};
  48 -
  49 +ATOMIC_NOTIFIER_HEAD(eeprom_chain);
  50
  51  static int eeprom_attach_adapter(struct i2c_adapter *adapter);
  52  static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
  53 @@ -189,6 +172,7 @@
  54         data->valid = 0;
  55         mutex_init(&data->update_lock);
  56         data->nature = UNKNOWN;
  57 +       data->attr = &eeprom_attr;
  58
  59         /* Tell the I2C layer a new client has arrived */
  60         if ((err = i2c_attach_client(new_client)))
  61 @@ -212,6 +196,9 @@
  62         if (err)
  63                 goto exit_detach;
  64
  65 +       /* call the notifier chain */
  66 +       atomic_notifier_call_chain(&eeprom_chain, EEPROM_REGISTER, data);
  67 +
  68         return 0;
  69
  70  exit_detach:
  71 @@ -237,6 +224,41 @@
  72         return 0;
  73  }
  74
  75 +/**
  76 + * register_eeprom_notifier - register a 'user' of EEPROM devices.
  77 + * @nb: pointer to notifier info structure
  78 + *
  79 + * Registers a callback function to be called upon detection
  80 + * of an EEPROM device.  Detection invokes the 'add' callback
  81 + * with the kobj of the mutex and a bin_attribute which allows
  82 + * read from the EEPROM.  The intention is that the notifier
  83 + * will be able to read system configuration from the notifier.
  84 + *
  85 + * Only EEPROMs detected *after* the addition of the notifier
  86 + * are notified.  I.e. EEPROMs already known to the system
  87 + * will not be notified - add the notifier from board level
  88 + * code!
  89 + */
  90 +int register_eeprom_notifier(struct notifier_block *nb)
  91 +{
  92 +       return atomic_notifier_chain_register(&eeprom_chain, nb);
  93 +}
  94 +
  95 +/**
  96 + *     unregister_eeprom_notifier - unregister a 'user' of EEPROM devices.
  97 + *     @old: pointer to notifier info structure
  98 + *
  99 + *     Removes a callback function from the list of 'users' to be
 100 + *     notified upon detection of EEPROM devices.
 101 + */
 102 +int unregister_eeprom_notifier(struct notifier_block *nb)
 103 +{
 104 +       return atomic_notifier_chain_unregister(&eeprom_chain, nb);
 105 +}
 106 +
 107 +EXPORT_SYMBOL_GPL(register_eeprom_notifier);
 108 +EXPORT_SYMBOL_GPL(unregister_eeprom_notifier);
 109 +
 110  static int __init eeprom_init(void)
 111  {
 112         return i2c_add_driver(&eeprom_driver);
 113 Index: linux-2.6.21-rc1-arm/include/linux/eeprom.h
 114 ===================================================================
 115 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
 116 +++ linux-2.6.21-rc1-arm/include/linux/eeprom.h 2007-02-21 02:25:01.000000000 -0800
 117 @@ -0,0 +1,71 @@
 118 +#ifndef _LINUX_EEPROM_H
 119 +#define _LINUX_EEPROM_H
 120 +/*
 121 + * $Id: 45-eeprom-new-notifier.patch,v 1.2 2006/03/27 11:10:19 azummo Exp $
 122 + *
 123 + *  Copyright (C) 2006 John Bowler
 124 + */
 125 +
 126 +/*
 127 + * This program is free software; you can redistribute it and/or modify
 128 + * it under the terms of the GNU General Public License as published by
 129 + * the Free Software Foundation; either version 2 of the License, or
 130 + * (at your option) any later version.
 131 + *
 132 + * This program is distributed in the hope that it will be useful,
 133 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
 134 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 135 + * GNU General Public License for more details.
 136 + *
 137 + * You should have received a copy of the GNU General Public License
 138 + * along with this program; if not, write to the Free Software
 139 + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 140 + */
 141 +
 142 +#ifndef __KERNEL__
 143 +#error This is a kernel header
 144 +#endif
 145 +
 146 +#include <linux/list.h>
 147 +#include <linux/kobject.h>
 148 +#include <linux/sysfs.h>
 149 +
 150 +/* Size of EEPROM in bytes */
 151 +#define EEPROM_SIZE             256
 152 +
 153 +/* possible types of eeprom devices */
 154 +enum eeprom_nature {
 155 +       UNKNOWN,
 156 +       VAIO,
 157 +};
 158 +
 159 +/* Each client has this additional data */
 160 +struct eeprom_data {
 161 +       struct i2c_client client;
 162 +       struct mutex update_lock;
 163 +       u8 valid;                       /* bitfield, bit!=0 if slice is valid */
 164 +       unsigned long last_updated[8];  /* In jiffies, 8 slices */
 165 +       u8 data[EEPROM_SIZE];           /* Register values */
 166 +       enum eeprom_nature nature;
 167 +       struct bin_attribute *attr;
 168 +};
 169 +
 170 +/*
 171 + * This is very basic.
 172 + *
 173 + * If an EEPROM is detected on the I2C bus (this only works for
 174 + * I2C EEPROMs) the notifier chain  is called with
 175 + * both the I2C information and the kobject for the sysfs
 176 + * device which has been registers.  It is then possible to
 177 + * read from the device via the bin_attribute::read method
 178 + * to extract configuration information.
 179 + *
 180 + * Register the notifier in the board level code, there is no
 181 + * need to unregister it but you can if you want (it will save
 182 + * a little bit or kernel memory to do so).
 183 + */
 184 +
 185 +extern int register_eeprom_notifier(struct notifier_block *nb);
 186 +extern int unregister_eeprom_notifier(struct notifier_block *nb);
 187 +
 188 +#endif /* _LINUX_EEPROM_H */
 189 Index: linux-2.6.21-rc1-arm/include/linux/notifier.h
 190 ===================================================================
 191 --- linux-2.6.21-rc1-arm.orig/include/linux/notifier.h  2007-02-21 02:24:14.000000000 -0800
 192 +++ linux-2.6.21-rc1-arm/include/linux/notifier.h       2007-02-21 02:25:01.000000000 -0800
 193 @@ -187,5 +187,8 @@
 194  #define CPU_DOWN_FAILED                0x0006 /* CPU (unsigned)v NOT going down */
 195  #define CPU_DEAD               0x0007 /* CPU (unsigned)v dead */
 196
 197 +/* eeprom notifier chain */
 198 +#define EEPROM_REGISTER                0x0001
 199 +
 200  #endif /* __KERNEL__ */
 201  #endif /* _LINUX_NOTIFIER_H */