diff options
author | David Brownell <david-b@pacbell.net> | 2007-05-01 23:26:31 +0200 |
---|---|---|
committer | Jean Delvare <khali@hyperion.delvare> | 2007-05-01 23:26:31 +0200 |
commit | 9c1600eda42e52796f49b36cf15b9debcfd09bea (patch) | |
tree | fe93f5924c7777cd5c3cc1ef6033dd2dfae542b5 /include/linux | |
parent | 4298cfc3eb6110df989f784be516c6340c597a66 (diff) |
i2c: Add i2c_board_info and i2c_new_device()
This provides partial support for new-style I2C driver binding. It builds
on "struct i2c_board_info" declarations that identify I2C devices on a given
board. This is needed on systems with I2C devices that can't be fully probed
and/or autoconfigured, such as many embedded Linux configurations where the
way a given I2C device is wired may affect how it must be used.
There are two models for declaring such devices:
* LATE -- using a public function i2c_new_device(). This lets modules
declare I2C devices found *AFTER* a given I2C adapter becomes available.
For example, a PCI card could create adapters giving access to utility
chips on that card, and this would be used to associate those chips with
those adapters.
* EARLY -- from arch_initcall() level code, using a non-exported function
i2c_register_board_info(). This copies the declarations *BEFORE* such
an i2c_adapter becomes available, arranging that i2c_new_device() will
be called later when i2c-core registers the relevant i2c_adapter.
For example, arch/.../.../board-*.c files would declare the I2C devices
along with their platform data, and I2C devices would behave much like
PNPACPI devices. (That is, both enumerate from board-specific tables.)
To match the exported i2c_new_device(), the previously-private function
i2c_unregister_device() is now exported.
Pending later patches using these new APIs, this is effectively a NOP.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/i2c.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 6802c3a0a3a..382a43bf3ad 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -172,6 +172,7 @@ struct i2c_client { int usage_count; /* How many accesses currently */ /* to the client */ struct device dev; /* the device structure */ + int irq; /* irq issued by device (or -1) */ char driver_name[KOBJ_NAME_LEN]; struct list_head list; struct completion released; @@ -193,6 +194,67 @@ static inline void i2c_set_clientdata (struct i2c_client *dev, void *data) dev_set_drvdata (&dev->dev, data); } +/** + * struct i2c_board_info - template for device creation + * @driver_name: identifies the driver to be bound to the device + * @type: optional chip type information, to initialize i2c_client.name + * @flags: to initialize i2c_client.flags + * @addr: stored in i2c_client.addr + * @platform_data: stored in i2c_client.dev.platform_data + * @irq: stored in i2c_client.irq + + * I2C doesn't actually support hardware probing, although controllers and + * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's + * a device at a given address. Drivers commonly need more information than + * that, such as chip type, configuration, associated IRQ, and so on. + * + * i2c_board_info is used to build tables of information listing I2C devices + * that are present. This information is used to grow the driver model tree + * for "new style" I2C drivers. For mainboards this is done statically using + * i2c_register_board_info(), where @bus_num represents an adapter that isn't + * yet available. For add-on boards, i2c_new_device() does this dynamically + * with the adapter already known. + */ +struct i2c_board_info { + char driver_name[KOBJ_NAME_LEN]; + char type[I2C_NAME_SIZE]; + unsigned short flags; + unsigned short addr; + void *platform_data; + int irq; +}; + +/** + * I2C_BOARD_INFO - macro used to list an i2c device and its driver + * @driver: identifies the driver to use with the device + * @dev_addr: the device's address on the bus. + * + * This macro initializes essential fields of a struct i2c_board_info, + * declaring what has been provided on a particular board. Optional + * fields (such as the chip type, its associated irq, or device-specific + * platform_data) are provided using conventional syntax. + */ +#define I2C_BOARD_INFO(driver,dev_addr) \ + .driver_name = (driver), .addr = (dev_addr) + + +/* Add-on boards should register/unregister their devices; e.g. a board + * with integrated I2C, a config eeprom, sensors, and a codec that's + * used in conjunction with the primary hardware. + */ +extern struct i2c_client * +i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); + +extern void i2c_unregister_device(struct i2c_client *); + +/* Mainboard arch_initcall() code should register all its I2C devices. + * This is done at arch_initcall time, before declaring any i2c adapters. + * Modules for add-on boards must use other calls. + */ +extern int +i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned n); + + /* * The following structs are for those who like to implement new bus drivers: * i2c_algorithm is the interface to a class of hardware solutions which can |