Re: Reading a config file in a driver ....

Olof Johansson wrote:

On Wed, Jan 02, 2008 at 09:03:20PM -0800, Misbah khan wrote:
  

quoted

Hi all ....

I am writing a LCD driver in which the default configuration for LCD would
be loded at the Init . This default configuration if keep in the driver then
for a change in default configuration we need to compile the driver which we
never want . Hence we want a .config file in /etc/lcd.config dir which could
be changed and the next boot will take this configuration as the default
configuration. 

I need to know How to read from the config file in the driver form the dir
/etc/lcd.config. The driver would be installed at boot up 
    

The driver/kernel shouldn't read the file directly, if anything you
should have a userspace tool that reads it and adjusts the driver via
sysfs or similar. That tool can be run from some of the init scripts,
or from the ramdisk in case you want to do it early.
  

What I've done in the past is to use module_param() to define variables 
that get set when the module is loaded. Then all you need to do is edit 
the /etc/modules file and change the parameter value. However, this 
technique is only efficient if only a few parameters will ever change. 
If you need to change more than a few parameters, Olof's suggestion 
would be preferred.

Carlos