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SIN210的LED硬件连接图如下

                                                  图3-0：SIN210  LED

一、编写LED驱动

1、LED 驱动属于字符设备,我们进入 Linux 内核的字符设备驱动目录,进行编辑。
2、新建文件 led.c 并对其进行编辑
3、在文件中添加如下代码:

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/serial_core.h>
#include <linux/gpio.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/usb/ch9.h>
#include <linux/pwm_backlight.h>
#include <linux/spi/spi.h>
#include <linux/gpio_keys.h>
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
#include <asm/setup.h>
#include <asm/mach-types.h>
#include <mach/map.h>
#include <mach/regs-mem.h>
#include <mach/regs-gpio.h>
#include <mach/gpio-bank.h>
#include <plat/s5pv210.h>
#include <plat/gpio-cfg.h>
#include <mach/gpio-bank-b.h>
#define LED_ON 0
#define LED_OFF 1
static unsigned long led_table [] = {
S5PV210_GPJ4(2),
S5PV210_GPJ4(1),
S5PV210_GPJ4(0),
S5PV210_GPJ3(7),
};
static unsigned long led_cfg_table [] = {
S3C_GPIO_OUTPUT,
S3C_GPIO_OUTPUT,
S3C_GPIO_OUTPUT,
S3C_GPIO_OUTPUT,
};
static int led_open(struct inode *inode, struct file *file)
{
int i;
for(i = 0; i < 4; i++)
{
s3c_gpio_cfgpin(led_table[i], led_cfg_table[i]);
}
return 0;
}
static int led_ioctl(struct inode *indoe, struct file *file,
unsigned int cmd, unsigned long arg)
{
if (arg > 4)
return -EINVAL;
switch(cmd)
{
case LED_ON:
s3c_gpio_setpin(led_table[arg], 0);
printk("led[%d] on\r\n", arg);
break;
case LED_OFF:
s3c_gpio_setpin(led_table[arg], 1);
printk("led[%d] off\r\n", arg);
break;
default:
break;
}
return 0;
}
static struct file_operations leds_fops = {
.owner = THIS_MODULE,
.open
= led_open,
.ioctl
= led_ioctl,
};
static int __init leds_init(void)
{
struct cdev *led_cdev;
struct class *led_class;
led_cdev = cdev_alloc();
cdev_init(led_cdev, &leds_fops);
led_cdev->owner = THIS_MODULE;
dev_t devid;
alloc_chrdev_region(&devid, 0, 1, "led");
cdev_add(led_cdev,devid,1);
led_class = class_create(THIS_MODULE,"led_class");
device_create(led_class, NULL, devid, NULL,"led");
printk("LEDS initialized.\n");
}
module_init(leds_init);
MODULE_AUTHOR("alexlee");
MODULE_DESCRIPTION("LEDS DRIVER");
MODULE_LICENSE("GPL");

二、编写LED应用程序

1、创建 led_test.c 文件
2、加入如下代码:

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/input.h>
#define IOCTL_LED_ON   0
#define IOCTL_LED_OFF  1

void usage(char *exename)
{
printf("Usage:\n");
printf("
%s <led_no> <on/off>\n", exename);
printf("
led_no = 1, 2, 3, 4\n");
}
int main(int argc, char **argv)
{
unsigned int led_no;
int fd = -1;
if (argc != 3)
goto err;
fd = open("/dev/led", O_RDWR);
if (fd < 0) {
printf("Can't open /dev/leds\n");
return -1;
}
led_no = strtoul(argv[1], 0, 0) - 1;
if (led_no > 5)
goto err;
if (!strcmp(argv[2], "on")) {
ioctl(fd, IOCTL_LED_ON, led_no);
} else if (!strcmp(argv[2], "off")) {
ioctl(fd, IOCTL_LED_OFF, led_no);
} else {
goto err;
}
printf("IOCTL no = [%d],[%s]\r\n", led_no,argv[2]);
close(fd);
return 0;
err:
if (fd > 0)
close(fd);
usage(argv[0]);
return -1;
}

#
# General Makefile
Exec := led_test
Obj := led_test.c
CC := arm-linux-gcc
$(Exec) : $(Obj)
$(CC) -o $@ $(Obj) $(LDLIBS$(LDLIBS-$(@)))
clean:
rm -vf $(Exec) *.elf *.o

如下图所示

                                                                                                                    图 3-1

                                                                                                                      图 3-2

                                                                                                                       图 3-3

每天进步一点点，每天都有新发现。走在学习的小路上。。。。。。