linux驅動編程實踐之LED驅動

開發板：TQ2440

核心：2.6.30.4-EmbedSky

實現目標：控制led開關，併當前讀取狀態

-------驅動實現  mini2440_leds.c-------

#include <linux/miscdevice.h>#include <linux/delay.h>#include <asm/irq.h>#include <mach/regs-gpio.h>#include <mach/hardware.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/init.h>#include <linux/mm.h>#include <linux/fs.h>#include <linux/types.h>#include <linux/delay.h>#include <linux/moduleparam.h>#include <linux/slab.h>#include <linux/errno.h>#include <linux/ioctl.h>#include <linux/cdev.h>#include <linux/string.h>#include <linux/list.h>#include <linux/pci.h>#include <asm/uaccess.h>#include <asm/atomic.h>#include <asm/unistd.h>#define DEVICE_NAME "leds"   //要操作的裝置名稱，載入成功後在/dev/下出現//操作的4個ledstatic unsigned long led_table [] = { S3C2410_GPB5, S3C2410_GPB6, S3C2410_GPB7, S3C2410_GPB8,};//輸出static unsigned int led_cfg_table [] = { S3C2410_GPB5_OUTP, S3C2410_GPB6_OUTP, S3C2410_GPB7_OUTP, S3C2410_GPB8_OUTP,};/*static unsigned int led_cfg_table1 [] = { S3C2410_GPB5_INP, S3C2410_GPB6_INP, S3C2410_GPB7_INP, S3C2410_GPB8_INP,};*/static int sbc2440_leds_ioctl( struct inode *inode,  struct file *file,  unsigned int cmd,  unsigned long arg){        unsigned char i,tmp;          switch(cmd) { case 0: case 1:  if (arg > 4) {   return -EINVAL;  }  s3c2410_gpio_cfgpin(led_table[arg], led_cfg_table[arg]);  s3c2410_gpio_setpin(led_table[arg], !cmd); //關或開  return 0; case 2:    tmp = s3c2410_gpio_getpin(led_table[arg]); //讀取狀態                tmp = tmp >>(arg+5);  return (unsigned int)tmp; default:  return -EINVAL; }}static struct file_operations dev_fops = { .owner = THIS_MODULE, .ioctl = sbc2440_leds_ioctl,};//混雜結構static struct miscdevice misc = { .minor = MISC_DYNAMIC_MINOR, .name = DEVICE_NAME, .fops = &dev_fops,};static int __init dev_init(void){ int ret; int i; //初始化四個led,並開啟 for (i = 0; i < 4; i++) {  s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);  s3c2410_gpio_setpin(led_table[i], 0); } ret = misc_register(&misc); printk (DEVICE_NAME"\tinitialized\n"); return ret;}static void __exit dev_exit(void){ misc_deregister(&misc);}module_init(dev_init);module_exit(dev_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("FriendlyARM Inc.");

======應用程式app-led.c======
 

#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <sys/ioctl.h>int main(int argc, char **argv){    int on;    int led_no;    int fd;    if (argc != 3 || sscanf(argv[1], "%d", &led_no) != 1 || sscanf(argv[2],"%d", &on) != 1 ||            on < 0 || on > 2 || led_no < 0 || led_no > 3) {        fprintf(stderr, "Usage: leds led_no 0|1|2\n");        exit(1);    }    fd = open("/dev/leds", 0);    if (fd < 0) {        perror("open device leds");        exit(1);    }    if(on==2) //讀取led狀態    {        printf("state:=%d\n",ioctl(fd, on, led_no));    }    else      //控制led開或關，即0，1    {        ioctl(fd, on, led_no);    }      close(fd);    return 0;}

=========Makefile==========

ifneq ($(KERNELRELEASE),)obj-m := mini2440_leds.oelse KDIR := /opt/guoqian/opt/EmbedSky/linux-2.6.30.4all: make -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-linux-clean: rm -f *.ko *.o *.mod.o *.mod.c *.symvers  modul*endif

=======操作結果======
[root@EmbedSky /tmp]# insmod mini2440_leds.ko
[root@EmbedSky /tmp]# ./app-led 1 2
state:=0
[root@EmbedSky /tmp]# ./app-led 1 0
[root@EmbedSky /tmp]# ./app-led 1 2
state:=1
[root@EmbedSky /tmp]#