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Commit e9f1373b authored by David Brownell's avatar David Brownell Committed by Jean Delvare
Browse files

i2c: Add i2c_new_dummy() utility 



This adds a i2c_new_dummy() primitive to help work with devices
that consume multiple addresses, which include many I2C eeproms
and at least one RTC.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 0b987dcd

drivers/i2c/i2c-core.c

+58 −1
Original line number Diff line number Diff line
@@ -296,6 +296,50 @@ void i2c_unregister_device(struct i2c_client *client) 
EXPORT_SYMBOL_GPL(i2c_unregister_device);





static int dummy_nop(struct i2c_client *client)

{

	return 0;

}



static struct i2c_driver dummy_driver = {

	.driver.name	= "dummy",

	.probe		= dummy_nop,

	.remove		= dummy_nop,

};



/**

 * i2c_new_dummy - return a new i2c device bound to a dummy driver

 * @adapter: the adapter managing the device

 * @address: seven bit address to be used

 * @type: optional label used for i2c_client.name

 * Context: can sleep

 *

 * This returns an I2C client bound to the "dummy" driver, intended for use

 * with devices that consume multiple addresses.  Examples of such chips

 * include various EEPROMS (like 24c04 and 24c08 models).

 *

 * These dummy devices have two main uses.  First, most I2C and SMBus calls

 * except i2c_transfer() need a client handle; the dummy will be that handle.

 * And second, this prevents the specified address from being bound to a

 * different driver.

 *

 * This returns the new i2c client, which should be saved for later use with

 * i2c_unregister_device(); or NULL to indicate an error.

 */

struct i2c_client *

i2c_new_dummy(struct i2c_adapter *adapter, u16 address, const char *type)

{

	struct i2c_board_info info = {

		.driver_name	= "dummy",

		.addr		= address,

	};



	if (type)

		strlcpy(info.type, type, sizeof info.type);

	return i2c_new_device(adapter, &info);

}

EXPORT_SYMBOL_GPL(i2c_new_dummy);



/* ------------------------------------------------------------------------- */



/* I2C bus adapters -- one roots each I2C or SMBUS segment */
@@ -841,11 +885,24 @@ static int __init i2c_init(void) 
	retval = bus_register(&i2c_bus_type);

	if (retval)

		return retval;

	return class_register(&i2c_adapter_class);

	retval = class_register(&i2c_adapter_class);

	if (retval)

		goto bus_err;

	retval = i2c_add_driver(&dummy_driver);

	if (retval)

		goto class_err;

	return 0;



class_err:

	class_unregister(&i2c_adapter_class);

bus_err:

	bus_unregister(&i2c_bus_type);

	return retval;

}



static void __exit i2c_exit(void)

{

	i2c_del_driver(&dummy_driver);

	class_unregister(&i2c_adapter_class);

	bus_unregister(&i2c_bus_type);

}

include/linux/i2c.h

+6 −0
Original line number Diff line number Diff line
@@ -259,6 +259,12 @@ i2c_new_probed_device(struct i2c_adapter *adap, 
		      struct i2c_board_info *info,

		      unsigned short const *addr_list);



/* For devices that use several addresses, use i2c_new_dummy() to make

 * client handles for the extra addresses.

 */

extern struct i2c_client *

i2c_new_dummy(struct i2c_adapter *adap, u16 address, const char *type);



extern void i2c_unregister_device(struct i2c_client *);



/* Mainboard arch_initcall() code should register all its I2C devices.