【原创】Tiny6410简单驱动 --- LED控制
【原创】Tiny6410简单驱动 --- LED灯控制
编写驱动之前记住一个原则：驱动程序提供机制而不提供策略，即驱动只管做什么，怎么做的问题交给应用程序。
依据上述原则，此文的简单驱动只实现四个LED的开和关，而要怎样用这开和关就交给应用程序。
LED硬件结构和相关寄存器
如下图，应设置输出模式（即cpu向LED管脚输出信号），低电平点亮，高电平熄灭。
my_led_module.c源代码（驱动程序）
驱动程序的构建方式和其Makefile文件参考链接http://blog.csdn.net/geng823/article/details/37355109#t4
<span style="font-size:18px;"><span style="font-size:18px;">#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <asm/irq.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>
#include <mach/map.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>
#include <plat/gpio-cfg.h>
#include <mach/gpio-bank-e.h>
#include <mach/gpio-bank-k.h>
#define DEVICE_NAME "my_led" //设备名称设为 my_led
#define ALL_LED_ON 0<span style="white-space:pre"> </span>//四个灯全点亮
#define ALL_LED_OFF 1<span style="white-space:pre"> </span>//四个灯全熄灭
static long s3c6410_leds_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
switch(cmd) {
unsigned tmp;
case ALL_LED_ON: //四个灯全亮
tmp = readl(S3C64XX_GPKDAT);
tmp &= ~(0xF << 4);
writel(tmp, S3C64XX_GPKDAT);
break;
case ALL_LED_OFF: //四个灯全灭
tmp = readl(S3C64XX_GPKDAT);
tmp |= (0xF << 4);
writel(tmp, S3C64XX_GPKDAT);
break;
default:
return -EINVAL;
}
}
static struct file_operations dev_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = s3c6410_leds_ioctl,
};
static struct miscdevice misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};
static int __init dev_init(void)
{
int ret;
{
unsigned tmp;
//将S3C64XX_GPKCON配制成输出，0xffffU<<16表示控制四个LED灯
tmp = readl(S3C64XX_GPKCON);
tmp = (tmp & ~(0xffffU<<16))|(0x1111U<<16);
writel(tmp, S3C64XX_GPKCON);
//低电平有效，初始时将四个灯都关掉
tmp = readl(S3C64XX_GPKDAT);
tmp |= (0xF << 4);
writel(tmp, S3C64XX_GPKDAT);
}
ret = misc_register(&misc);//注册杂项设备
printk (DEVICE_NAME"\tinitialized\n");
return ret;
}
static void __exit dev_exit(void)
{
misc_deregister(&misc);//注销杂项设备
printk (DEVICE_NAME"\tuninstalled\n");
}
module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("GENG");</span></span>
my_led.c源代码（应用程序）
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdlib.h>
#define ALL_LED_SPLASH 'r' //四个灯间隔1s同时闪烁
#define ALL_LED_STOP 's' //四个灯停止闪烁
#define DEVICE_QUIT 'q' //设备退出
#define ALL_LED_ON 0 //四个灯全点亮
#define ALL_LED_OFF 1 //四个灯全熄灭
/*
* 此函数用来获得从键盘输入的一个字符，也可以直接在主函数中用getchar()获得
*/
static int getch(void)
{
struct termios oldt,newt;
int ch;
if (!isatty(STDIN_FILENO)) {
fprintf(stderr, "this problem should be run at a terminal\n");
exit(1);
}
// save terminal setting
if(tcgetattr(STDIN_FILENO, &oldt) < 0) {
perror("save the terminal setting");
exit(1);
}
// set terminal as need
newt = oldt;
newt.c_lflag &= ~( ICANON | ECHO );
if(tcsetattr(STDIN_FILENO,TCSANOW, &newt) < 0) {
perror("set terminal");
exit(1);
}
ch = getchar();
// restore termial setting
if(tcsetattr(STDIN_FILENO,TCSANOW,&oldt) < 0) {
perror("restore the termial setting");
exit(1);
}
return ch;
}
int main(int argc, char **argv)
{
int fd;
//打开设备
fd = open("/dev/my_led", 0);
if (fd < 0) {
fd = open("/dev/my_led", 0);
}
if (fd < 0) {
perror("open device my_led");
exit(1);
}
printf( "\nmy_led TEST ( led Control )\n" );
while(1)
{
int c;
int i;
c = getch();
//通过输入的字符选择功能
//注意：输入字符后，需要再按回车键
switch(c) {
case ALL_LED_SPLASH: //四个led灯同时以1s的间隔闪烁
for (i = 0; i < 10; i++){
ioctl(fd, ALL_LED_ON);//同时亮
sleep(1);//睡一秒
ioctl(fd, ALL_LED_OFF);//同时灭
sleep(1);//睡一秒
}
break;
case ALL_LED_STOP: //四个灯全灭
ioctl(fd, ALL_LED_OFF);//
break;
case DEVICE_QUIT://关闭设备，退出
close(fd);
exit(0);
default://其他字符，继续等待输入
break;
}
}
return 0;
}
应用程序的Makefile
<span style="font-size:18px;"><span style="font-size:18px;"><span style="font-size:18px;"># ---------------------------------------------------------------------------- # Makefile for building tapp # # Copyright 2010 FriendlyARM (http://www.arm9.net/) # ifndef DESTDIR DESTDIR ?= /tmp/FriendlyARM/mini6410/rootfs endif CFLAGS = -Wall -O2 CC = arm-linux-gcc INSTALL = install TARGET = my_led all: $(TARGET) led: my_led.c $(CC) $(CFLAGS) $< -o $@ install: $(TARGET) $(INSTALL) $^ $(DESTDIR)/usr/bin clean distclean: rm -rf *.o $(TARGET) # ---------------------------------------------------------------------------- .PHONY: $(PHONY) install clean distclean # End of file # vim: syntax=make </span></span></span>
