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: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
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2 changed files with 64 additions and 1 deletions
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@ -296,6 +296,50 @@ void i2c_unregister_device(struct i2c_client *client)
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EXPORT_SYMBOL_GPL(i2c_unregister_device);
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static int dummy_nop(struct i2c_client *client)
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{
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return 0;
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}
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static struct i2c_driver dummy_driver = {
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.driver.name = "dummy",
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.probe = dummy_nop,
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.remove = dummy_nop,
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};
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/**
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* i2c_new_dummy - return a new i2c device bound to a dummy driver
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* @adapter: the adapter managing the device
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* @address: seven bit address to be used
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* @type: optional label used for i2c_client.name
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* Context: can sleep
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*
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* This returns an I2C client bound to the "dummy" driver, intended for use
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* with devices that consume multiple addresses. Examples of such chips
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* include various EEPROMS (like 24c04 and 24c08 models).
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*
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* These dummy devices have two main uses. First, most I2C and SMBus calls
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* except i2c_transfer() need a client handle; the dummy will be that handle.
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* And second, this prevents the specified address from being bound to a
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* different driver.
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*
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* This returns the new i2c client, which should be saved for later use with
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* i2c_unregister_device(); or NULL to indicate an error.
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*/
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struct i2c_client *
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i2c_new_dummy(struct i2c_adapter *adapter, u16 address, const char *type)
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{
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struct i2c_board_info info = {
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.driver_name = "dummy",
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.addr = address,
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};
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if (type)
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strlcpy(info.type, type, sizeof info.type);
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return i2c_new_device(adapter, &info);
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}
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EXPORT_SYMBOL_GPL(i2c_new_dummy);
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/* ------------------------------------------------------------------------- */
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/* I2C bus adapters -- one roots each I2C or SMBUS segment */
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@ -841,11 +885,24 @@ static int __init i2c_init(void)
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retval = bus_register(&i2c_bus_type);
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if (retval)
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return retval;
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return class_register(&i2c_adapter_class);
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retval = class_register(&i2c_adapter_class);
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if (retval)
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goto bus_err;
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retval = i2c_add_driver(&dummy_driver);
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if (retval)
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goto class_err;
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return 0;
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class_err:
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class_unregister(&i2c_adapter_class);
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bus_err:
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bus_unregister(&i2c_bus_type);
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return retval;
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}
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static void __exit i2c_exit(void)
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{
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i2c_del_driver(&dummy_driver);
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class_unregister(&i2c_adapter_class);
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bus_unregister(&i2c_bus_type);
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}
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@ -259,6 +259,12 @@ i2c_new_probed_device(struct i2c_adapter *adap,
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struct i2c_board_info *info,
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unsigned short const *addr_list);
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/* For devices that use several addresses, use i2c_new_dummy() to make
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* client handles for the extra addresses.
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*/
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extern struct i2c_client *
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i2c_new_dummy(struct i2c_adapter *adap, u16 address, const char *type);
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extern void i2c_unregister_device(struct i2c_client *);
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/* Mainboard arch_initcall() code should register all its I2C devices.
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