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i2c: Document i2c_new_device() 

Document the new i2c_new_device(), i2c_new_probed_device() and
i2c_unregister_device() functions.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
hifive-unleashed-5.1
Jean Delvare 2007-05-01 23:26:32 +02:00 committed by Jean Delvare
parent 12b5053ac5
commit ce9e0794c2
1 changed files with 38 additions and 0 deletions
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38
Documentation/i2c/writing-clients
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@ -200,6 +200,44 @@ device typing support in the hardware. The driver and module name should
match, so hotplug/coldplug mechanisms will modprobe the driver.
Device Creation (Standard driver model)
---------------------------------------
If you know for a fact that an I2C device is connected to a given I2C bus,
you can instantiate that device by simply filling an i2c_board_info
structure with the device address and driver name, and calling
i2c_new_device(). This will create the device, then the driver core will
take care of finding the right driver and will call its probe() method.
If a driver supports different device types, you can specify the type you
want using the type field. You can also specify an IRQ and platform data
if needed.
Sometimes you know that a device is connected to a given I2C bus, but you
don't know the exact address it uses. This happens on TV adapters for
example, where the same driver supports dozens of slightly different
models, and I2C device addresses change from one model to the next. In
that case, you can use the i2c_new_probed_device() variant, which is
similar to i2c_new_device(), except that it takes an additional list of
possible I2C addresses to probe. A device is created for the first
responsive address in the list. If you expect more than one device to be
present in the address range, simply call i2c_new_probed_device() that
many times.
The call to i2c_new_device() or i2c_new_probed_device() typically happens
in the I2C bus driver. You may want to save the returned i2c_client
reference for later use.
Device Deletion (Standard driver model)
---------------------------------------
Each I2C device which has been created using i2c_new_device() or
i2c_new_probed_device() can be unregistered by calling
i2c_unregister_device(). If you don't call it explicitly, it will be
called automatically before the underlying I2C bus itself is removed, as a
device can't survive its parent in the device driver model.
Legacy Driver Binding Model
---------------------------