diff options
Diffstat (limited to 'Documentation/i2c/writing-clients')
| -rw-r--r-- | Documentation/i2c/writing-clients | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index 0a74603eb67..6b344b516bf 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -38,7 +38,7 @@ static struct i2c_driver foo_driver = { .name = "foo", }, - .id_table = foo_ids, + .id_table = foo_idtable, .probe = foo_probe, .remove = foo_remove, /* if device autodetection is needed: */ @@ -74,6 +74,11 @@ structure at all. You should use this to keep device-specific data. /* retrieve the value */ void *i2c_get_clientdata(const struct i2c_client *client); +Note that starting with kernel 2.6.34, you don't have to set the `data' field +to NULL in remove() or if probe() failed anymore. The i2c-core does this +automatically on these occasions. Those are also the only times the core will +touch this field. + Accessing the client ==================== @@ -240,21 +245,17 @@ static int __init foo_init(void) { return i2c_add_driver(&foo_driver); } +module_init(foo_init); static void __exit foo_cleanup(void) { i2c_del_driver(&foo_driver); } +module_exit(foo_cleanup); -/* Substitute your own name and email address */ -MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>" -MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices"); - -/* a few non-GPL license types are also allowed */ -MODULE_LICENSE("GPL"); +The module_i2c_driver() macro can be used to reduce above code. -module_init(foo_init); -module_exit(foo_cleanup); +module_i2c_driver(foo_driver); Note that some functions are marked by `__init'. These functions can be removed after kernel booting (or module loading) is completed. @@ -262,6 +263,17 @@ Likewise, functions marked by `__exit' are dropped by the compiler when the code is built into the kernel, as they would never be called. +Driver Information +================== + +/* Substitute your own name and email address */ +MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>" +MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices"); + +/* a few non-GPL license types are also allowed */ +MODULE_LICENSE("GPL"); + + Power Management ================ @@ -318,8 +330,9 @@ Plain I2C communication These routines read and write some bytes from/to a client. The client contains the i2c address, so you do not have to include it. The second parameter contains the bytes to read/write, the third the number of bytes -to read/write (must be less than the length of the buffer.) Returned is -the actual number of bytes read/written. +to read/write (must be less than the length of the buffer, also should be +less than 64k since msg.len is u16.) Returned is the actual number of bytes +read/written. int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num); @@ -352,8 +365,6 @@ in terms of it. Never use this function directly! s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command); s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value); - s32 i2c_smbus_process_call(struct i2c_client *client, - u8 command, u16 value); s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command, u8 *values); s32 i2c_smbus_write_block_data(struct i2c_client *client, @@ -368,6 +379,8 @@ These ones were removed from i2c-core because they had no users, but could be added back later if needed: s32 i2c_smbus_write_quick(struct i2c_client *client, u8 value); + s32 i2c_smbus_process_call(struct i2c_client *client, + u8 command, u16 value); s32 i2c_smbus_block_process_call(struct i2c_client *client, u8 command, u8 length, u8 *values); |