vserver 1.9.5.x5

[linux-2.6.git] / Documentation / i2c / writing-clients

diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients
index a454212..011e920 100644 (file)
--- a/Documentation/i2c/writing-clients
+++ b/Documentation/i2c/writing-clients
@@ -24,22 +24,24 @@ all clients from it. Remember, a driver structure contains general access
 routines, a client structure specific information like the actual I2C
 address.
 
-  static struct i2c_driver foo_driver = {
-    .owner          = THIS_MODULE,
-    .name           = "Foo version 2.3 driver",
-    .id             = I2C_DRIVERID_FOO, /* usually from i2c-id.h */
-    .flags          = I2C_DF_NOTIFY,
-    .attach_adapter = &foo_attach_adapter,
-    .detach_client  = &foo_detach_client,
-    .command        = &foo_command /* may be NULL */
-  }
+static struct i2c_driver foo_driver = {
+       .owner          = THIS_MODULE,
+       .name           = "Foo version 2.3 driver",
+       .id             = I2C_DRIVERID_FOO, /* from i2c-id.h, optional */
+       .flags          = I2C_DF_NOTIFY,
+       .attach_adapter = &foo_attach_adapter,
+       .detach_client  = &foo_detach_client,
+       .command        = &foo_command /* may be NULL */
+}
  
 The name can be chosen freely, and may be upto 40 characters long. Please
 use something descriptive here.
 
-The id should be a unique ID. The range 0xf000 to 0xffff is reserved for
-local use, and you can use one of those until you start distributing the
-driver. Before you do that, contact the i2c authors to get your own ID(s).
+If used, the id should be a unique ID. The range 0xf000 to 0xffff is
+reserved for local use, and you can use one of those until you start
+distributing the driver, at which time you should contact the i2c authors
+to get your own ID(s). Note that most of the time you don't need an ID
+at all so you can just omit it.
 
 Don't worry about the flags field; just put I2C_DF_NOTIFY into it. This
 means that your driver will be notified when new adapters are found.
@@ -569,7 +571,7 @@ the driver module is usually enough.
      have to be cleaned up! */
   static int __initdata foo_initialized = 0;
 
-  int __init foo_init(void)
+  static int __init foo_init(void)
   {
     int res;
     printk("foo version %s (%s)\n",FOO_VERSION,FOO_DATE);
@@ -583,41 +585,27 @@ the driver module is usually enough.
     return 0;
   }
 
-  int __init foo_cleanup(void)
+  void foo_cleanup(void)
   {
-    int res;
     if (foo_initialized == 1) {
       if ((res = i2c_del_driver(&foo_driver))) {
         printk("foo: Driver registration failed, module not removed.\n");
-        return res;
+        return;
       }
       foo_initialized --;
     }
-    return 0;
   }
 
-  #ifdef MODULE
-
   /* Substitute your own name and email address */
   MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"
   MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices");
 
-  int init_module(void)
-  {
-    return foo_init();
-  }
-
-  int cleanup_module(void)
-  {
-    return foo_cleanup();
-  }
-
-  #endif /* def MODULE */
+  module_init(foo_init);
+  module_exit(foo_cleanup);
 
 Note that some functions are marked by `__init', and some data structures
-by `__init_data'. If this driver is compiled as part of the kernel (instead
-of as a module), those functions and structures can be removed after
-kernel booting is completed.
+by `__init_data'.  Hose functions and structures can be removed after
+kernel booting (or module loading) is completed.
 
 Command function
 ================
@@ -688,14 +676,26 @@ SMBus communication
   extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command);
   extern s32 i2c_smbus_write_word_data(struct i2c_client * client,
                                        u8 command, u16 value);
-  extern s32 i2c_smbus_process_call(struct i2c_client * client,
-                                    u8 command, u16 value);
-  extern s32 i2c_smbus_read_block_data(struct i2c_client * client,
-                                       u8 command, u8 *values);
   extern s32 i2c_smbus_write_block_data(struct i2c_client * client,
                                         u8 command, u8 length,
                                         u8 *values);
 
+These ones were removed in Linux 2.6.10 because they had no users, but could
+be added back later if needed:
+
+  extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client,
+                                           u8 command, u8 *values);
+  extern s32 i2c_smbus_read_block_data(struct i2c_client * client,
+                                       u8 command, u8 *values);
+  extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client * client,
+                                            u8 command, u8 length,
+                                            u8 *values);
+  extern s32 i2c_smbus_process_call(struct i2c_client * client,
+                                    u8 command, u16 value);
+  extern s32 i2c_smbus_block_process_call(struct i2c_client *client,
+                                          u8 command, u8 length,
+                                          u8 *values)
+
 All these transactions return -1 on failure. The 'write' transactions 
 return 0 on success; the 'read' transactions return the read value, except 
 for read_block, which returns the number of values read. The block buffers