Adding Interrupt service routine in kernel

Question

I am trying to add a switch/GPIO interrupt. I want to write it as part of kernel source tree. After building the kernel image and deploying to my custom board it has to appear in proc/interrupts. I have already written the module and it is working if do insmod. Instead of compiling separately i want it to be a part of my kernel tree. What are the steps to add the irq to kernel source.

Answer 1

Actually if you have written the module inside the kernel tree, it is pretty straightforward:

Lets say you put the source code in drivers directory, so the hierarchy looks as follows: drivers/hello Kconfig Makefile hello.c

In drivers/Makefile you should add the following:

obj-$(CONFIG-HELLO) += hello/

In drivers/Kconfig you should add the following:

source "drivers/hello/Kconfig"

Sample code for drivers/hello/Kconfig:

config HELLO
tristate "Hello world module"
default n
help
   Enable Hello world module support

Sample code for drivers/hello/Makefile:

obj-$(CONFIG_HELLO) += hello.o

Sample code for drivers/hello.c:

#include <linux/module.h>
#include <linux/moduleparam.h>

...
...

static int __init hello_init(void)
{
   ...
}

static void __exit hello_exit(void)
{
   ...
}

module_init(hello_init);
module_exit(hello_exit);

MODULE_AUTHOR("Obi One Kenoby");
MODULE_DESCRIPTION("Hello Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");

Now you should be able to see the hello module in make menuconfig - select 'm' for module and '*' for built in. the module_init/module_exit macros works with both options.