慢慢学Linux驱动开发，第九篇，tiny6410_LED驱动

     一直在看代码，今天准备真正去试试，就拿tiny6410的LED灯开刀，虽说是自己写，但实际上也是参考例程来的。不过还好基本的思路还是蛮清晰的。

 

     定义本次驱动为misc device（杂项设备驱动），包含头文件miscdevice.h，其实所谓的杂项驱动程序就是主设备号为10的字符设备驱动，其实就是用主设备号10调用了函数register_chrdev()。且misc device会自动在/dev目录下建立设备节点，而不需用mkmod手动建立。

 

开发板IO定义：

 

S3C6410 GPK口：

 

 

#include <linux/miscdevice.h>#include <linux/fs.h>#include <linux/pci.h>#include <mach/map.h>#include <mach/regs-gpio.h>#include <mach/gpio-bank-k.h>#include "leds.h"#define DEVICE_NAME "tiny6410_leds"MODULE_LICENSE("GPL");MODULE_AUTHOR("pang123hui");static long sbc2440_leds_ioctl(struct file *filp, unsigned int cmd, unsigned long arg){switch(cmd) {unsigned tmp;/*case 0:case 1:if(arg > 4){//非法参数return -EINVAL;}tmp = readl(S3C64XX_GPKDAT);tmp &= ~(1 << (3 + arg));tmp |= ((cmd) << (3 + arg));writel(tmp, S3C64XX_GPKDAT);return 0;*/case 1:case 2:case 3:case 4:tmp = readl(S3C64XX_GPKDAT);tmp = (tmp & ~(1<<(cmd - 1 + 4)))|(arg<<(cmd -1 + 4));writel(tmp, S3C64XX_GPKDAT);return 0;default:return -EINVAL;}}static struct file_operations dev_fops = {.owner= THIS_MODULE,.unlocked_ioctl= sbc2440_leds_ioctl,};//misc device：杂项设备，即主设备号为10的特殊字符设备static struct miscdevice misc = {//次设备号，注意不要与/proc/misc中已有杂项设备次设备号冲突//MISC_DYNAMIC_MINOR来动态获取次设备号.minor = MISC_DYNAMIC_MINOR,//设备名称.name = DEVICE_NAME,.fops = &dev_fops,};static int __init dev_init(void){int ret;{unsigned tmp;tmp = readl(S3C64XX_GPKCON);//GPKCON配置GPK4到GPK7配置为0001输出tmp = (tmp & ~(0xffffU<<16))|(0x1111U<<16);writel(tmp, S3C64XX_GPKCON);//GPKDAT[7:4] = 1//灯灭tmp = readl(S3C64XX_GPKDAT);tmp |= (0xF << 4);writel(tmp, S3C64XX_GPKDAT);//禁止上拉下拉tmp = readl(S3C64XX_GPKPUD);tmp &= (0x00 << 8);writel(tmp, S3C64XX_GPKPUD);}//该函数会自动创建设备节点，即设备文件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);

 

makefile

 

ifneq ($(KERNELRELEASE),) obj-m := leds.o else KERNELDIR := /opt/FriendlyARM/mini6410/linux/linux-2.6.38PWD:=$(shell pwd) all: make -C $(KERNELDIR) M=$(PWD) modules clean: rm -rf *.ko *.o *.mod.c *.mod.o *.symvers endif

 

leds_test

 

#include <stdio.h>//exit#include <stdlib.h>#include <sys/ioctl.h>int main(int argc, char **argv){int num = 0;int led_state = 1;int fd = 0;//参数赋值if(argc != 3 || sscanf(argv[1],"%d", &num) != 1 || sscanf(argv[2], "%d", &led_state) != 1 || num > 4 || led_state > 1){fprintf(stderr, "error/n");exit(1);}printf("num = %d, led_state = %d/n", num, led_state);fd = open("/dev/tiny6410_leds", 0);if (fd < 0) {fd = open("/dev/tiny6410_leds0", 0);}if (fd < 0) {perror("open device leds");exit(1);}ioctl(fd, num, led_state);printf("led%d/n", num);close(fd);return 0;}