三星6410 led平台驱动

源程序

1、应用程序led.c

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/ioctl.h>

#define LED_MAGIC 'L'
#define LED_ON    _IOW(LED_MAGIC, 0, int)
#define LED_OFF    _IOW(LED_MAGIC, 1, int)

int main(int argc, char **argv)
{
int fd;
fd = open("/dev/led", O_RDWR);
if (fd < 0) {
perror("open");
exit(1);
}
while(1)
{
ioctl(fd, LED_ON);
usleep(100000);
ioctl(fd, LED_OFF);
usleep(100000);
}
return 0;
}

2、驱动程序led_dev.c

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/platform_device.h>
#include <linux/of_device.h>
#include <asm/io.h>
#include <asm/uaccess.h>

MODULE_LICENSE("Dual BSD/GPL");

#define LED_MAGIC 'L'
#define LED_ON    _IOW(LED_MAGIC, 0, int)
#define LED_OFF    _IOW(LED_MAGIC, 1, int)

#define LED_MA 500
#define LED_MI 0
#define LED_NUM 1

//#define FS4412_GPX2CON    0x11000C40
//#define FS4412_GPX2DAT    0x11000C44

static unsigned int *gpx2con;
static unsigned int *gpx2dat;
//存放映射的地址
struct cdev cdev;

static int s5pv210_led_open(struct inode *inode, struct file *file)
{
return 0;
}

static int s5pv210_led_release(struct inode *inode, struct file *file)
{
return 0;
}

static long s5pv210_led_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case LED_ON:
writel(readl(gpx2dat) | 1 << 7, gpx2dat);
break;
case LED_OFF:
writel(readl(gpx2dat) & ~(1 << 7), gpx2dat);
break;
}
return 0;
}

struct file_operations s5pv210_led_fops = {
.owner = THIS_MODULE,
.open = s5pv210_led_open,
.release = s5pv210_led_release,
.unlocked_ioctl = s5pv210_led_unlocked_ioctl,
};

static int led_init(struct platform_device *pdev)
{
/****************设备号初始化**********************************/
dev_t devno = MKDEV(LED_MA, LED_MI);
int ret = register_chrdev_region(devno, LED_NUM, "led");
if (ret < 0) {
printk("register_chrdev_region\n");
return ret;
}
cdev_init(&cdev, &s5pv210_led_fops);
cdev.owner = THIS_MODULE;
ret = cdev_add(&cdev, devno, LED_NUM);
if (ret < 0) {
printk("cdev_add\n");
goto err1;
}
**********************根据设备树获取地址***************************/
struct resource * p = platform_get_resource(pdev,IORESOURCE_MEM,0);
gpx2con = ioremap(p->start, 4);
if (gpx2con == NULL) {
printk("ioremap gpx2con\n");
ret = -ENOMEM;
goto err2;
}
struct resource * q = platform_get_resource(pdev,IORESOURCE_MEM,1);
gpx2dat = ioremap(q->start, 4);
if (gpx2dat == NULL) {
printk("ioremap gpx2dat\n");
ret = -ENOMEM;
goto err3;
}
writel((readl(gpx2con) & ~(0xf << 28)) | (0x1 << 28), gpx2con);
writel(readl(gpx2dat) & ~(0x1<<7), gpx2dat);

printk("Led init\n");
return 0;
err3:
iounmap(gpx2con);
err2:
cdev_del(&cdev);
err1:
unregister_chrdev_region(devno, LED_NUM);
return ret;
}

static void led_exit(void)
{
dev_t devno = MKDEV(LED_MA, LED_MI);
iounmap(gpx2dat);
iounmap(gpx2con);
cdev_del(&cdev);
unregister_chrdev_region(devno, LED_NUM);
printk("Led exit\n");
}

//module_init(s5pv210_led_init);
//module_exit(s5pv210_led_exit);
static const struct of_device_id fs4412_dt_of_matches[] = {
{ .compatible = "led"},    //这个字符串 必须与设备树里的字符串一致
{},
};
MODULE_DEVICE_TABLE(of, fs4412_dt_of_matches);

struct platform_driver led_platform_driver = {
.driver = {
.name = "led",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(fs4412_dt_of_matches),
},
.probe = led_init,    //对应初始化函数
.remove = led_exit, //对应退出函数
};
module_platform_driver(led_platform_driver);  //驱动默认从该函数执行

3、设备树配置

在内核linux-3.14下执行 vim /arch/arm/boot/dts/exynos4412-fs4412.dts添加

重新编译设备树 make dtbs
复制设备树 cp  /arch/arm/boot/dts/exynos4412-fs4412.dtb到tftp共享目录下替换了原先的设备树。

4、执行驱动的makefile

#module templet
ifeq ($(KERNELRELEASE),)
KERNELDIR ?= /home/farsight/remove/linux-3.14
PWD := $(shell pwd)

all:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
arm-none-linux-gnueabi-gcc led.c -o led
cp -af *.ko /home/farsight/remove/rootfs
cp led /home/farsight/remove/rootfs
clean:
rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions Module* modules* a.out
else
obj-m := led_dev.o
endif

5、启动tftp和nfs执行程序

“`

执行sudo service tftpd-hpa restart命令，开启tftp服务

重新驱动nfs服务：sudo /etc/init.d/nfs-kernel-server restart

下载驱动，创建设备文件，执行应用程序，即可