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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:03 EST.

1	I2C device driver binding control from user-space
2	=================================================
3	
4	Up to kernel 2.6.32, many i2c drivers used helper macros provided by
5	<linux/i2c.h> which created standard module parameters to let the user
6	control how the driver would probe i2c buses and attach to devices. These
7	parameters were known as "probe" (to let the driver probe for an extra
8	address), "force" (to forcibly attach the driver to a given device) and
9	"ignore" (to prevent a driver from probing a given address).
10	
11	With the conversion of the i2c subsystem to the standard device driver
12	binding model, it became clear that these per-module parameters were no
13	longer needed, and that a centralized implementation was possible. The new,
14	sysfs-based interface is described in the documentation file
15	"instantiating-devices", section "Method 4: Instantiate from user-space".
16	
17	Below is a mapping from the old module parameters to the new interface.
18	
19	Attaching a driver to an I2C device
20	-----------------------------------
21	
22	Old method (module parameters):
23	# modprobe <driver> probe=1,0x2d
24	# modprobe <driver> force=1,0x2d
25	# modprobe <driver> force_<device>=1,0x2d
26	
27	New method (sysfs interface):
28	# echo <device> 0x2d > /sys/bus/i2c/devices/i2c-1/new_device
29	
30	Preventing a driver from attaching to an I2C device
31	---------------------------------------------------
32	
33	Old method (module parameters):
34	# modprobe <driver> ignore=1,0x2f
35	
36	New method (sysfs interface):
37	# echo dummy 0x2f > /sys/bus/i2c/devices/i2c-1/new_device
38	# modprobe <driver>
39	
40	Of course, it is important to instantiate the "dummy" device before loading
41	the driver. The dummy device will be handled by i2c-core itself, preventing
42	other drivers from binding to it later on. If there is a real device at the
43	problematic address, and you want another driver to bind to it, then simply
44	pass the name of the device in question instead of "dummy".
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