Driver for keys on GPIO using input-subsystem way

/**

  * Driver for keys on GPIO using input-subsystem way

 */

Driver Test:



----------------------------------------------------------driver---------------------------------------------------------------

#include <linux/module.h>

#include <linux/version.h>

  

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/sched.h>

#include <linux/pm.h>

#include <linux/sysctl.h>

#include <linux/proc_fs.h>

#include <linux/delay.h>

#include <linux/platform_device.h>

#include <linux/input.h>

#include <linux/irq.h>

#include <linux/gpio_keys.h>

  

#include <asm/gpio.h>

#define DRIVER_NAME "czinputsubsys_keys"

static struct input_dev *czinput_dev;

//tips: why no static?

struct czkey_desc {

     unsigned char * name;

  int irq;

  int pin;

  int code;

};

//gpio_to_irq(S3C2410_GPF1) is wrong!

static struct czkey_desc aczkey_desc[4] = {

     {"L",                   IRQ_EINT1, S3C2410_GPF1, KEY_L},

     {"S",                   IRQ_EINT4, S3C2410_GPF4, KEY_S},

     {"ENTER",        IRQ_EINT2, S3C2410_GPF2, KEY_ENTER},

     {"LEFTSHIFT", IRQ_EINT0, S3C2410_GPF0, KEY_LEFTSHIFT},

};

 static irqreturn_t czinputsubsys_keys_isr(int irq, void *dev_id)

 {

  printk("driver:czinputsubsys_keys_isr in\n");

  struct czkey_desc *pczkey_desc = (struct czkey_desc *)dev_id;

  int state = (gpio_get_value(pczkey_desc->pin) ? 1 : 0);

 

 

 // input_event(czinput_dev, czinput_dev->evbit[0], pczkey_desc->code, state);

 if(state){

   input_event(czinput_dev, EV_KEY, pczkey_desc->code, 1);//untest 2013.01.15

    printk("driver:czinputsubsys_keys_isr key state:%d\n",state);

  }

 else

  {

  input_event(czinput_dev, EV_KEY, pczkey_desc->code, 0);//untest 2013.01.15

   printk("driver:czinputsubsys_keys_isr key state:%d\n",state);

  }

 

  input_sync(czinput_dev);

  return IRQ_HANDLED;

 }

 

 static int czinputsubsys_keys_init(void)

 {

 printk("driver:czinputsubsys_key_init in\n");

 int error;

 int i ;

 czinput_dev = input_allocate_device();

 if (!czinput_dev){

  printk(KERN_ERR "Cannot request keypad device\n");

  return -ENOMEM;}

 else

  printk("Can request keypad device\n");

 //czinput_dev->evbit[0] =  BIT(EV_KEY) | BIT(EV_REP) | BIT(EV_REL);

 //czinput_dev->keybit[0] = BIT(KEY_L) | BIT(KEY_S) | BIT(KEY_ENTER) | BIT(KEY_LEFTSHIFT);

 //czinput_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);

 set_bit(EV_KEY, czinput_dev->evbit);//untest 2013.01.15

 set_bit(KEY_ENTER, czinput_dev->keybit);

 set_bit(KEY_L, czinput_dev->keybit);

 set_bit(KEY_S, czinput_dev->keybit);

 set_bit(KEY_LEFTSHIFT, czinput_dev->keybit);

 

 czinput_dev->name = DRIVER_NAME;

 //czinput_dev->phys = "gpio-keys/input0";

 //czinput_dev->dev.parent = &pdev->dev;

 //czinput_dev->id.bustype = BUS_HOST;

 //czinput_dev->id.vendor = 0x0001;

 //czinput_dev->id.product = 0x0001;

 //czinput_dev->id.version = 0x0100;

 error = input_register_device(czinput_dev);

 if (error)

    printk(KERN_ERR "Unable to register gpio-keys input device\n");

 else

    printk(KERN_ERR "able to register gpio-keys input device\n");

 

 //for(i=0;i<4;i++)

       // set_irq_type(aczkey_desc[i].irq, IRQ_TYPE_EDGE_BOTH);

//tips: about KERN_ERR?; about IRQF_SAMPLE_RANDOM

//tips: about IRQT_BOTHEDGE is the right way

 for(i=0;i<4;i++){

        error = request_irq(aczkey_desc[i].irq, czinputsubsys_keys_isr, IRQT_BOTHEDGE,

         aczkey_desc[i].name,&aczkey_desc[i]);

        if (error)

              printk(KERN_ERR "gpio-keys: unable to claim irq %d; error %d\n",aczkey_desc[i].irq, error);

     else

      printk("gpio-keys: able to claim irq %d\n",aczkey_desc[i].irq);

  }

 return 0;

 }

 static void czinputsubsys_keys_exit(void)

{

 printk("driver:czinputsubsys_key_exit in\n");

 int i;

 for(i=0;i<4;i++)

   free_irq(aczkey_desc[i].irq, &aczkey_desc[i]);

 input_unregister_device(czinput_dev);

 

 return;

}

 module_init(czinputsubsys_keys_init);

 module_exit(czinputsubsys_keys_exit);

 MODULE_AUTHOR("chaozang(cz) <zangchao.cn@gmail.com>, copy frm teacher:weidongshan,thanks so much!");

 MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");

 MODULE_LICENSE("GPL");

----------------------------------------------------test commands----------------------------------------------------------

# exec 0</dev/tty1

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