MINI2440 key input subsystem driver and test code analysis

Key input subsystem driver:

#include

#include

#include

#include

#include

#include /* for -EBUSY */

#include /* for request_region */

#include /* for loops_per_jiffy */

#include    /* for inb_p, outb_p, inb, outb, etc. */

#include /* for get_user, etc. */

#include   /* for wait_queue */

#include   /* for __init, module_{init,exit} */

#include   /* for POLLIN, etc. */

#include

#include

#include

#include

#include

#include

struct pin_desc {

    int     irq;

    int     pin;

    int     pin_state;

    char    *name;

    int     key_val;

    int     pin_val;

};

static struct pin_desc buttons_pin[] = {

    {IRQ_EINT8,    S3C2410_GPG(0),   S3C2410_GPG0_EINT8,    "KEY1",   BTN_0},

    {IRQ_EINT11,   S3C2410_GPG(3),   S3C2410_GPG3_EINT11,   "KEY3",   BTN_1},

    {IRQ_EINT13,   S3C2410_GPG(5),   S3C2410_GPG5_EINT13,   "KEY2",   BTN_2},

    {IRQ_EINT14,   S3C2410_GPG(6),   S3C2410_GPG6_EINT14,   "KEY4",   BTN_3},

    {IRQ_EINT15,   S3C2410_GPG(7),   S3C2410_GPG7_EINT15,   "KEY5",   BTN_4},

    {IRQ_EINT19,   S3C2410_GPG(11),  S3C2410_GPG11_EINT19,  "KEY6",   BTN_5},

};

static struct input_dev *buttons_input;

static irqreturn_t buttons_interrupt(int irq,void *dev_id)

{

    struct pin_desc *pin_desc = (struct pin_desc *)dev_id;

    int val;

    val = s3c2410_gpio_getpin(pin_desc->pin);

    input_event(buttons_input,EV_KEY,pin_desc->key_val, !val);

    input_sync(buttons_input);

    return IRQ_HANDLED;

}

static int __init buttons_init(void)

{

    int error;

    int i;

    buttons_input = input_allocate_device();

    if(!buttons_input)

        return  -ENOMEM;

#if 0

    buttons_input->evbit[0] = BIT(EV_KEY);

    buttons_input->keybit[BITS_TO_LONGS(KEY_L)] = BIT(KEY_L);

    buttons_input->keybit[BITS_TO_LONGS(KEY_S)] = BIT(KEY_S);

    buttons_input->keybit[BITS_TO_LONGS(KEY_ENTER)] = BIT(KEY_ENTER);

    buttons_input->keybit[BITS_TO_LONGS(KEY_LEFTSHIFT)] = BIT(KEY_LEFTSHIFT);

#endif

    set_bit(EV_KEY,buttons_input->evbit);

    for(i = 0;i    {

        set_bit(buttons_pin[i].key_val,buttons_input->keybit);

    }

    error = input_register_device(buttons_input);

    if(error){

        input_free_device(buttons_input);

        return -1;

    }

    for(i = 0;i    {

       s3c2410_gpio_cfgpin(buttons_pin[i].pin,buttons_pin[i].pin_state);

       request_irq(buttons_pin[i].irq,buttons_interrupt, IRQF_SHARED | IRQF_TRIGGER_RISING

               | IRQF_TRIGGER_FALLING,buttons_pin[i].name,(void *)&buttons_pin[i]);

    }

    return 0;

}

static void __exit buttons_exit(void)

{

    int i;

    for(i = 0; i< sizeof(buttons_pin)/sizeof(buttons_pin[0]); i++)

    {

        free_irq(buttons_pin[i].irq, (void *)&buttons_pin[i]);

    }

    input_unregister_device(buttons_input);

    input_free_device(buttons_input);

}

module_init(buttons_init);

module_exit(buttons_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("RopenYuan");

Key input subsystem test program

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

int main(void)

{

 int buttons_fd;

 int key_value,i=0,count;

 struct input_event ev_key;

 buttons_fd = open("/dev/input/event0", O_RDWR);

 if (buttons_fd < 0) {

  perror("open device buttons");

  exit(1);

 }

 for (;;) {

  count = read(buttons_fd,&ev_key,sizeof(struct input_event));

  for(i=0; i<(int)count/sizeof(struct input_event); i++)

   if(EV_KEY==ev_key.type)

    printf("type:%d,code:%d,value:%dn", ev_key.type,ev_key.code,ev_key.value);

   if(EV_SYN==ev_key.type)

    printf("syn eventnn");

    }

 close(buttons_fd);

 return 0;

}

MAKEFILE

ifneq ($(KERNELRELEASE),)

obj-m := buttons.o

else

#KDIR := /home/yuanpengjun/home/linuxeditorkernelfilesystem/kernal/linux-2.6.32/linux-2.6.32.2/

KDIR := /home/yuanpengjun/mini2440/kernel/linux-2.6.32.2/

all:

#  make -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-linux-

  make -C $(KDIR) M=$(PWD) modules

  /home/yuanpengjun/mini2440/editor/4.4.3/bin/arm-none-linux-gnueabi-gcc -o button button_app.c

clean:

  rm -f *.ko *.o *.mod.o *.mod.c *.symvers modul*

endif

The above driver code does not include fault tolerance processing, just to verify whether it can run successfully.

Input appears when loading the module: Unspecified device as /devices/virtual/input/input0  

The reason is that the member name in struct input_dev is not set in the driver. If there is a member named XXXX->name = "yyyyyyy", the following situation will occur after the driver module is loaded:

input: yyyyyyy as /devices/virtual/input/input0  

When uninstalling the module, rmmod: chdir(2.6.32.2): No such file or directory appears, and the module cannot be uninstalled from the system;

The reason is: When the current kernel module is inserted and uninstalled, it will be transferred to the directory /lib/modules/kernel version number/, in the format of /lib/modules/2.6.32.2/. In this case, the module will no longer appear. Unable to uninstall;