itrobotics

/*******************************************************************************
* Copyright (c) 2015 Song Yang @ ittraining
*
* All rights reserved.
* This program is free to use, but the ban on selling behavior.
* Modify the program must keep all the original text description.
*
* 保留所有權利。
* 本程式可任意使用，但是禁止販售行為。
* 修改程式時必須保留所有原有文字說明。

itrobotics

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<unistd.h>
#include<fcntl.h>
#include<time.h>

int main(int argc,char *argv[]){
	int dev_0 = open("/dev/mydev_0",O_RDWR);

itrobotics

[  788.476664]
[  788.476664] *****Some body is opening me at major 200  minor 0*****
[  788.476729]
[  788.476729] *****Some body is opening me at major 200  minor 1*****
[  798.479961] *****Some body is closing me at major 0*****
[  798.480004] *****Some body is closing me at major 1*****
[  814.005473] Goodbye
[  829.987718] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[  829.998678] pgd = d9ef0000
[  830.002707] [00000000] *pgd=1b2be831, *pte=00000000, *ppte=00000000

itrobotics

#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <linux/init.h>
#include <linux/cdev.h>

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/errno.h>

itrobotics

#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/cdev.h>
#include <linux/gpio.h>
#include <asm/uaccess.h>

#define LED0_GPIO 22
#define LED1_GPIO 27

itrobotics

/*******************************************************************************
* Copyright (c) 2015 Song Yang @ ittraining
*
* All rights reserved.
* This program is free to use, but the ban on selling behavior.
* Modify the program must keep all the original text description.
*
* Email: [email protected]
* Blog : http://blog.ittraining.com.tw
*******************************************************************************/

itrobotics

/*******************************************************************************
* Copyright (c) 2015 Song Yang @ ittraining
* 
* All rights reserved.
* This program is free to use, but the ban on selling behavior.
* Modify the program must keep all the original text description.
*
* 保留所有權利。
* 本程式可任意使用，但是禁止販售行為。
* 修改程式時必須保留所有原有文字說明。

itrobotics

// Simple Character Device Driver Module for Raspberry Pi.
/*
 * DESCRIPTION:
 *     a simple example of char device 
 *     this char device can control the GPIO by file operation : write
 *     to write specific message as command
 * */

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

itrobotics

// Reference to http://elinux.org/RPi_Low-level_peripherals

#define BCM2708_PERI_BASE       0x20000000
#define GPIO_BASE               (BCM2708_PERI_BASE + 0x200000)	// GPIO controller 
 
//#define BLOCK_SIZE 		(4*1024)
 
// GPIO setup macros. Always use INP_GPIO(x) before using OUT_GPIO(x)
#define INP_GPIO(g)   *(gpio.addr + ((g)/10)) &= ~(7<<(((g)%10)*3))
#define OUT_GPIO(g)   *(gpio.addr + ((g)/10)) |=  (1<<(((g)%10)*3))

itrobotics

#include <linux/kernel.h>
#include <linux/module.h>   
#include <asm/uaccess.h>
#include <linux/fs.h>      
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio.h>