驱动学习4--led静态映射
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驱动
#include <linux/module.h> // module_init module_exit#include <linux/init.h> // __init __exit#include <linux/fs.h> //register_chrdev file_operations#include <asm/uaccess.h> //copy_from_user copy_to_user#include <mach/regs-gpio.h> //gpio virtual address#include <mach/gpio-bank.h> //gpio virtual address#define DEMO_NAME "demo_char"#define GPJ0CON *((volatile unsigned int *)S5PV210_GPJ0CON)#define GPJ0DAT *((volatile unsigned int *)S5PV210_GPJ0DAT)static int my_major;static int demo_chrdev_open(struct inode *inode, struct file *file){ GPJ0CON &= 0xff000fff; GPJ0CON |= (1<<12)|(1<<16)|(1<<20); GPJ0DAT |= ((1<<3)|(1<<4)|(1<<5)); printk(KERN_INFO "demo_chrdev_open\n");/*open的调试代码*/ return 0;}static int demo_chrdev_release(struct inode *inode, struct file *file){ GPJ0DAT |= ((1<<3)|(1<<4)|(1<<5)); printk(KERN_INFO "demo_chrdev_release\n");/*close的调试代码*/ return 0;}static ssize_t demo_chrdev_write(struct file *file, const char __user *ubuf, size_t count, loff_t *ppos){ int ret = -1; char kbuf[100] = {0}; ret = copy_from_user(kbuf,ubuf,count);/*返回值为0成功*/ if(ret) { printk(KERN_ERR "copy_from_user fail\n"); return -EINVAL; } if(!strcmp(kbuf,"0")) GPJ0DAT &= ~((1<<3)|(1<<4)|(1<<5)); else if(!strcmp(kbuf,"1")) GPJ0DAT |= ((1<<3)|(1<<4)|(1<<5)); else printk(KERN_INFO "input err\r\n"); printk(KERN_INFO "copy_from_user %s\r\n",kbuf); return 0;}static const struct file_operations demo_fops = { .owner = THIS_MODULE,/*惯例,直接写即可*/ .open = demo_chrdev_open,/*把open的api与此函数联系起来*/ .release = demo_chrdev_release,/*把close的api于此函数联系起来*/ .write = demo_chrdev_write,/*把write的api于此函数联系起来*/};static int __init chrdev_init(void) /*模块安装*/{ my_major = register_chrdev(0,DEMO_NAME,&demo_fops);/*注册设备,0表示自动分配设备号*/ if(my_major<0){ printk(KERN_ERR "chrdev_init error.\n"); return -EINVAL; } printk(KERN_INFO "chrdev_init success.\n"); return 0;}static void __exit chrdev_exit(void)/*模块卸载*/{ unregister_chrdev(my_major,DEMO_NAME);/*注销设备*/ printk(KERN_INFO "chrdev_exit\n");}module_init(chrdev_init);module_exit(chrdev_exit);MODULE_LICENSE("GPL");/*描述模块的许可证*/MODULE_AUTHOR("Xin-Ya Zhu<mhzhuxinya@outlook.com>");/*描述模块的作者*/MODULE_DESCRIPTION("demo test");/*描述模块的介绍信息*/ MODULE_ALIAS("alias xxx");/*描述模块的别名信息*/
应用
#include <stdio.h>#include <string.h>#include <stdlib.h>#include <sys/types.h> //open close#include <sys/stat.h>#include <fcntl.h>#define FILE "/dev/demo_text"#define LED_ON "led_on"#define LED_OFF "led_off"int main(void){ int fd = -1; char buf[100] = {0}; fd = open(FILE,O_RDWR); if(fd<0) { printf("open error.\n"); return -1; } write(fd,LED_ON,strlen(LED_ON)); sleep(1); write(fd,LED_OFF,strlen(LED_OFF)); sleep(1); write(fd,LED_ON,strlen(LED_ON)); sleep(1); write(fd,LED_OFF,strlen(LED_OFF)); sleep(1); close(fd); return 0;}/***************************[root@zhuxinya text]# insmod demo.ko [ 2280.440257] chrdev_init success.[root@zhuxinya text]# mknod /dev/demo_text c 250 0[root@zhuxinya text]# ./app [ 2295.883318] demo_chrdev_open[ 2295.884771] copy_from_user 0[ 2296.887767] copy_from_user 1[ 2297.889327] copy_from_user 0[ 2298.890857] copy_from_user 1[ 2299.892409] demo_chrdev_release*****************************/
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