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Diffstat (limited to 'Documentation/i2c/old-module-parameters.rst')
| -rw-r--r-- | Documentation/i2c/old-module-parameters.rst | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/Documentation/i2c/old-module-parameters.rst b/Documentation/i2c/old-module-parameters.rst index a1939512ad66..38e55829dee8 100644 --- a/Documentation/i2c/old-module-parameters.rst +++ b/Documentation/i2c/old-module-parameters.rst @@ -1,19 +1,24 @@ -================================================= -I2C device driver binding control from user-space -================================================= +================================================================ +I2C device driver binding control from user-space in old kernels +================================================================ -Up to kernel 2.6.32, many i2c drivers used helper macros provided by +.. NOTE:: + Note: this section is only relevant if you are handling some old code + found in kernel 2.6. If you work with more recent kernels, you can + safely skip this section. + +Up to kernel 2.6.32, many I2C drivers used helper macros provided by <linux/i2c.h> which created standard module parameters to let the user -control how the driver would probe i2c buses and attach to devices. These -parameters were known as "probe" (to let the driver probe for an extra -address), "force" (to forcibly attach the driver to a given device) and -"ignore" (to prevent a driver from probing a given address). +control how the driver would probe I2C buses and attach to devices. These +parameters were known as ``probe`` (to let the driver probe for an extra +address), ``force`` (to forcibly attach the driver to a given device) and +``ignore`` (to prevent a driver from probing a given address). -With the conversion of the i2c subsystem to the standard device driver +With the conversion of the I2C subsystem to the standard device driver binding model, it became clear that these per-module parameters were no longer needed, and that a centralized implementation was possible. The new, -sysfs-based interface is described in the documentation file -"instantiating-devices", section "Method 4: Instantiate from user-space". +sysfs-based interface is described in :doc:`instantiating-devices`, section +"Method 4: Instantiate from user-space". Below is a mapping from the old module parameters to the new interface. @@ -42,8 +47,8 @@ New method (sysfs interface):: # echo dummy 0x2f > /sys/bus/i2c/devices/i2c-1/new_device # modprobe <driver> -Of course, it is important to instantiate the "dummy" device before loading +Of course, it is important to instantiate the ``dummy`` device before loading the driver. The dummy device will be handled by i2c-core itself, preventing other drivers from binding to it later on. If there is a real device at the problematic address, and you want another driver to bind to it, then simply -pass the name of the device in question instead of "dummy". +pass the name of the device in question instead of ``dummy``. |