1、添加设备树
在设备树
arch/arm64/boot/dts/rockchip/rk3399-firefly-linux.dts
中添加
gpio-led{
status = "okay";
compatible = "gpio-led";
gpio-led1 = <&gpio1 8 GPIO_ACTIVE_LOW>;
gpio-led2 = <&gpio1 9 GPIO_ACTIVE_LOW>;
};
2、驱动代码
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/uaccess.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/miscdevice.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/ioctl.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#include <linux/miscdevice.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#define LED_ON _IO('B',0)
#define LED_OFF _IO('B',1)
int gpio_led1,gpio_led2;
static long gec3399_led_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch(cmd)
{
case LED_ON:
gpio_set_value(gpio_led1,1);
gpio_set_value(gpio_led2,1);
break;
case LED_OFF:
gpio_set_value(gpio_led1,0);
gpio_set_value(gpio_led2,0);
break;
}
return 0;
}
static int gec3399_led_release(struct inode *inode, struct file *file)
{
gpio_set_value(gpio_led1,0);
gpio_set_value(gpio_led2,0);
return 0;
}
static const struct file_operations gec3399_led_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = gec3399_led_ioctl,
.release = gec3399_led_release,
};
static struct miscdevice gec3399_led_misc = {
.minor = MISC_DYNAMIC_MINOR,
.fops = &gec3399_led_fops,
.name = "led_drv",
};
static int gec3399_led_probe(struct platform_device *pdev)
{
int ret;
struct device_node *led_node = pdev->dev.of_node;
printk(KERN_ALERT"gpio-led math succee\n");
gpio_led1 = of_get_named_gpio(led_node,"gpio-led1", 0);
if (!gpio_is_valid(gpio_led1))
{
printk("gpio-led1: %d is invalid\n",gpio_led1);
ret = -ENODEV;
goto err_get_gpio1;
}
printk("gpio-led1 = %d\n",gpio_led1);
gpio_led2 = of_get_named_gpio(led_node,"gpio-led2", 0);
if (!gpio_is_valid(gpio_led2))
{
printk("gpio-led2: %d is invalid\n",gpio_led2);
ret = -ENODEV;
goto err_get_gpio1;
}
printk("gpio-led2 = %d\n",gpio_led2);
gpio_free(gpio_led1);
ret = gpio_request(gpio_led1,"GPIO_LED1");
if(ret < 0){
printk("gpio_request gpio = GPIO_LED1 error\n");
goto err_get_gpio1;
}
gpio_free(gpio_led2);
ret = gpio_request(gpio_led2,"GPIO_LED2");
if(ret < 0){
printk("gpio_request gpio = GPIO_LED1 error\n");
goto err_get_gpio2;
}
ret = gpio_direction_output(gpio_led1,0);
if(ret < 0){
printk("gpio direction input gpio = ak8963c_DYDR error\n");
goto err_gpio_direction;
}
ret = gpio_direction_output(gpio_led2,0);
if(ret < 0){
printk("gpio direction input gpio = ak8963c_DYDR error\n");
goto err_gpio_direction;
}
ret = misc_register(&gec3399_led_misc);
if(ret < 0){
printk("misc register error\n");
goto err_misc_register;
}
printk( KERN_ALERT "led dirve install succee\n");
return 0;
err_misc_register:
err_gpio_direction:
gpio_free(gpio_led2);
err_get_gpio2:
gpio_free(gpio_led1);
err_get_gpio1:
return ret;
}
static int gec3399_led_remove(struct platform_device *pdev)
{
gpio_free(gpio_led1);
gpio_free(gpio_led2);
misc_deregister(&gec3399_led_misc);
printk(KERN_ALERT "led dirve rmove succee\n");
return 0;
}
static const struct of_device_id of_gec_leder_match[] = {
{ .compatible = "gpio-led", },
{},
};
static struct platform_driver gec3399_led_driver = {
.driver = {
.name ="gpio-led",
.owner = THIS_MODULE,
.of_match_table = of_gec_leder_match,
},
.probe = gec3399_led_probe,
.remove = gec3399_led_remove,
};
module_platform_driver(gec3399_led_driver);
MODULE_DESCRIPTION("led driver for RK3399");
MODULE_LICENSE("GPL");
MODULE_VERSION("V1.0");
3、测试代码
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#define LED_ON _IO('B',0)
#define LED_OFF _IO('B',1)
int main(void)
{
int fd_led;
int ret;
fd_led = open("/dev/led_drv", O_WRONLY);
if(fd_led < 0)
{
perror("open led driver");
return -1;
}
while(1)
{
ret = ioctl(fd_led,LED_ON);
if(ret < 0)
perror("write led driver ");
sleep(1);
ret = ioctl(fd_led,LED_OFF);
if(ret < 0 )
perror("write led driver ");
sleep(1);
}
close(fd_led);
return 0;
}
4、Makefile文件
obj-m += led_drv.o
KERNELDIR:=/file/RK3399Pro/rk3399pro_git_repo/kernel
PWD:=$(shell pwd)
default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
test:
aarch64-linux-gnu-gcc led_test.c -o led_test
clean:
rm -rf *.o *.order .*.cmd *.ko *.mod.c *.symvers *.tmp_versions led_test
5、测试
insmod led_drv.ko
./led_test
实现LED灯的闪烁
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