Driver porting: more module changes

Driver porting: more module changes

Posted Feb 14, 2003 8:41 UTC (Fri) by rusty (subscriber, #26)
Parent article: Driver porting: more module changes

Regarding module_param(): MODULE_PARM() will certainly stay throughout the 2.6 series, so no need to change existing code just yet.

However, the real power of module_param() is that you can easily build your own types: i.e. it is extensible. One way to do this is to use the underlying module_param_call() macro, but a more convenient way goes like this:

 #define param_check_mytype(name, p) /* optional typechecking */
 int param_set_mytype(const char *val, struct kernel_param *kp) ...
 int param_get_mytype(char *buffer, struct kernel_param *kp) ...

Then you can use it as follows:

 module_param(myparam, mytype, 000);

This is extremely useful for implementing things like ranges, or any holes in the provided macros.

The other issue to note is that (as an unrelated bonus) the module_param parameters are also available as boot parameters, prefixed with the module name and a "." (- and _ can be used interchangably here). Previously __setup() was needed for boot parameters, and MODULE_PARM for module parameters.

Hope that helps!
Rusty.

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