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Subjectgetting configuration info into a driver at load-time
Hi folks, i'm looking for a way to pass structured configuration 
information to a device driver at load-time.

I'm working on a device driver for a family of FPGA cards for motion
control of industrial robots and computer-controlled machine tools. The
driver loads the FPGA firmware with request_firmware() and sends it to
the FPGA.

Once the FPGA is up and running, the user needs to configure the
firmware specifically for their machine, by telling the firmware things
like "my machine has two stepper motors and three servo motors, and the
second servo motor has an encoder with an index channel". The details
of the information being relayed isnt important, the key thing is that
it's like a struct containing a couple of arrays of different kinds
structs, something like this:

struct config {

struct {
bool enabled;
bool index_enabled;
bool index_mask_enabled;
} encoder_config[];

struct {
bool enabled;
} pwmgen_config[];

struct {
bool enabled;
uint width;
} stepgen_config[];

char *firmware;

bool enable_raw;

} board_config;


Each board that the driver finds should get its own "board_config".

I thought about exposing this config structure in /sys or /proc (in a
per-board directory), and let the user poke in the config values after
the driver has loaded, but I'd really prefer to make the information
available at load-time.

Currently the driver has a module param array of char*, with each
board's configuration encoded into an ascii string which gets decoded
"by hand" in the driver. Pretty grotty.

Is there some easier/cleaner way to do this?

--
Sebastian Kuzminsky
what i like best about 12648430 is the coffee


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