![[DM8168]Linux下控制GPIO实现LED流水灯](https://image.shishitao.com:8440/aHR0cHM6Ly9ia3FzaW1nLmlrYWZhbi5jb20vdXBsb2FkL2NoYXRncHQtcy5wbmc%2FIQ%3D%3D.png?!?w=700&webp=1 "[DM8168]Linux下控制GPIO实现LED流水灯")
首先加载驱动模块，应用程序通过调用API实现GPIO控制功能。
驱动程序：
/*
* fileName: led_gpio.c
* just for LED GPIO test
* GP1_14 -> HDD
* GP1_15 -> REC
* GP1_27 -> NC
* GP1_28 -> IR
*/ #include <linux/device.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/list.h>
#include <linux/cdev.h>
#include <linux/proc_fs.h>
#include <linux/mm.h>
#include <linux/seq_file.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <asm/io.h>
#include <linux/io.h>
#include <mach/gpio.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/ioctl.h> #define DRIVERNAME "led4" #define CTRL_MODULE_BASE_ADDR 0x48140000 // PANEL CON
#define conf_gpio46 (CTRL_MODULE_BASE_ADDR + 0x0B04)
#define conf_gpio47 (CTRL_MODULE_BASE_ADDR + 0x0B08)
#define conf_gpio59 (CTRL_MODULE_BASE_ADDR + 0x0AB8)
#define conf_gpio60 (CTRL_MODULE_BASE_ADDR + 0x0ABC) #define WR_MEM_32(addr, data) *(unsigned int*)OMAP2_L4_IO_ADDRESS(addr) = (unsigned int)(data)
#define RD_MEM_32(addr) *(unsigned int*)OMAP2_L4_IO_ADDRESS(addr) static dev_t dev;
static struct cdev cdev;
static struct class *led_gpio_class = NULL;
static int gpio[]; static int led_gpio_open(struct inode *inode, struct file *file);
static int led_gpio_close(struct inode *inode, struct file *file);
static long led_gpio_ioctl(struct file *file, unsigned int val, unsigned long pin);
//static int valid_check(unsigned int gpioNum); //////////////////////////////////////////////////////////////////////////////
/*-
static int valid_check(unsigned int gpioNum)
{
if((gpioNum==46)||(gpioNum==47)||(gpioNum==59)||(gpioNum==60))
return 1;
return -1;
}
-*/ static void store_gpio_pin(void)
{
// store gpio pinmux
gpio[] = RD_MEM_32(conf_gpio46);
gpio[] = RD_MEM_32(conf_gpio47);
gpio[] = RD_MEM_32(conf_gpio59);
gpio[] = RD_MEM_32(conf_gpio60);
} static void recover_gpio_pin(void)
{
// recover gpio pinmux
WR_MEM_32(conf_gpio46, gpio[]);
WR_MEM_32(conf_gpio47, gpio[]);
WR_MEM_32(conf_gpio59, gpio[]);
WR_MEM_32(conf_gpio60, gpio[]);
gpio_free(gpio[]);
gpio_free(gpio[]);
gpio_free(gpio[]);
gpio_free(gpio[]);
} static void config_gpio_pin(void)
{
WR_MEM_32(conf_gpio46, );
gpio_request(, "gpio46_en"); // request gpio46
gpio_direction_output(, ); WR_MEM_32(conf_gpio47, );
gpio_request(, "gpio47_en"); // request gpio47
gpio_direction_output(, ); WR_MEM_32(conf_gpio59, );
gpio_request(, "gpio59_en"); // request gpio59
gpio_direction_output(, ); WR_MEM_32(conf_gpio60, );
gpio_request(, "gpio60_en"); // request gpio60
gpio_direction_output(, );
} static int led_gpio_open(struct inode *inode, struct file *file)
{
// store gpio pin value
store_gpio_pin();
// configure all used gpio
config_gpio_pin();
return ;
} static int led_gpio_close(struct inode *inode, struct file *file)
{
// recover gpio pin mux;
recover_gpio_pin();
return ;
} static long led_gpio_ioctl(struct file *file, unsigned int val, unsigned long pin)
{
if(valid_check(pin) < ){
printk("GPIO:%d can't use!\n", (int)pin);
return -;
}
gpio_set_value(pin, val); return ;
} static struct file_operations led_gpio_fops =
{
.owner = THIS_MODULE,
.open = led_gpio_open,
.release = led_gpio_close,
.unlocked_ioctl = led_gpio_ioctl,
}; static int __init LED_init(void)
{
int result; result = alloc_chrdev_region(&dev, , , DRIVERNAME);
if(result < ){
printk("Error registering led_gpio character device\n");
return -ENODEV;
}
printk(KERN_INFO "led_gpio major#: %d, minor#: %d\n", MAJOR(dev), MINOR(dev)); cdev_init(&cdev, &led_gpio_fops);
cdev.owner = THIS_MODULE;
cdev.ops = &led_gpio_fops; result = cdev_add(&cdev, dev, );
if(result){
unregister_chrdev_region(dev, );
printk("Error adding led_gpio.. error no:%d\n",result);
return -EINVAL;
}
led_gpio_class = class_create(THIS_MODULE, DRIVERNAME);
device_create(led_gpio_class, NULL, dev, NULL, DRIVERNAME); printk(DRIVERNAME "initialized"); return ;
} static void __exit LED_exit(void)
{
printk("led chrdev exit!\n");
cdev_del(&cdev);
unregister_chrdev_region(dev, );
device_destroy(led_gpio_class, dev);
class_destroy(led_gpio_class);
} module_init(LED_init);
module_exit(LED_exit);
MODULE_LICENSE("GPL");
API函数：
#ifndef API_LED_H
#define API_LED_H
#include <stdio.h> #ifdef __cplusplus
extern "C" {
#endif int api_led_open(void);
int api_led_close(int fd_led);
int api_led_ioctl(int fd_led, unsigned int pin, unsigned int val); #ifdef __cplusplus
}
#endif #endif
#include "api_led.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h> #define DEVICENAME "/dev/led4" int api_led_open(void)
{
int fd_led;
if((fd_led=open(DEVICENAME,O_RDWR)) <= -){
printf("open device error\n");
return -;
}
return fd_led;
} int api_led_close(int fd_led)
{
if( == close(fd_led))
return ;
else
return -;
} int api_led_ioctl(int fd_led, unsigned int pin, unsigned int val)
{
if(ioctl(fd_led, val, pin) < ){
printf("write error\n");
return -;
}else{
return ;
}
}
应用程序：
/*- test for Lcd12864 -*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "api_led.h"
int main(void)
{
int fd_led;
// int num;
// int ret;
int delay = ; fd_led = api_led_open(); if(fd_led < ){
printf("fd_led open failed!\n");
return -;
} api_led_ioctl(fd_led, , );
api_led_ioctl(fd_led, , ); printf("Hello, Water LEDs run!\n"); while(delay--){
api_led_ioctl(fd_led, , ); // LED IR off
api_led_ioctl(fd_led, , ); // LED HDD on
usleep();
api_led_ioctl(fd_led, , ); // LED HDD off
api_led_ioctl(fd_led, , ); // LED REC on
usleep();
api_led_ioctl(fd_led, , ); // LED REC off
api_led_ioctl(fd_led, , ); // LED IR on
usleep();
// if(count < 0) return -1;
// printf("light LED HDD!\n ")
} api_led_close(fd_led); return ;
}