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1. GPIO的char型驱动,这里主要就是点个灯,感受一下驱动的设计和硬件的控制驱动程序:
- #include <linux/init.h>
- #include <linux/module.h>
- #include <linux/leds.h>
- #include <linux/io.h>
- #include <linux/semaphore.h>
- #include <linux/kernel.h>
- #include <linux/cdev.h>
- #include <linux/types.h>
- #include <linux/fs.h>
- #include <mach/gpio.h>
- #include <plat/mux.h>
- #include <linux/gpio.h>
- /*******************************************/
- #define NAME "leds"
- #define GPIO_TO_PIN(bank, gpio) (32 * (bank) + (gpio))
- static int major =251;//定义主设备号
- /*******************************************/
- void led_on(void)
- {
- gpio_set_value(GPIO_TO_PIN(1,22), 1);
- }
- void led_off(void)
- {
- gpio_set_value(GPIO_TO_PIN(1,22), 0);
- }
- void led_init(void)
- {
- int result;
- /* Allocating GPIOs and setting direction */
- result = gpio_request(GPIO_TO_PIN(1,22), "Leds");//usr1
- if (result != 0)
- printk("gpio_request(1_22) failed!\n");
- result = gpio_direction_output(GPIO_TO_PIN(1,22), 1);
- if (result != 0)
- printk("gpio_direction(1_22) failed!\n");
- }
- struct light_dev
- {
- struct cdev cdev;
- unsigned char value;
- };
- struct light_dev *light_devp;
- MODULE_AUTHOR("chenzhufly");
- MODULE_LICENSE("Dual BSD/GPL");
- // 打开和关闭函数
- int light_open(struct inode *inode,struct file *filp)
- {
- struct light_dev *dev;
- // 获得设备结构体指针
- dev = container_of(inode->i_cdev,struct light_dev,cdev);
- // 让设备结构体作为设备的私有信息
- filp->private_data = dev;
- return 0;
- }
- int light_release(struct inode *inode,struct file *filp)
- {
- return 0;
- }
- // ioctl
- int light_ioctl(struct file *filp,unsigned int cmd,
- unsigned long arg)
- {
- struct light_dev *dev = filp->private_data;
- switch(cmd)
- {
- case 0:
- dev->value = 0;
- led_off();
- break;
- case 1:
- dev->value = 1;
- led_on();
- break;
- default:
- return -ENOTTY;
- // break;
- }
- return 0;
- }
- struct file_operations light_fops =
- {
- .owner = THIS_MODULE,
- .unlocked_ioctl = light_ioctl,
- .open = light_open,
- .release = light_release,
- };
- // 模块加载函数
- int light_init(void)
- {
- int ret;
- led_init();
- printk(KERN_ALERT "led modules is install\n");
- ret=register_chrdev(major,NAME,&light_fops);
- if(ret<0)
- {
- printk("unable to register myled driver!\n");
- return ret;
- }
- return 0;
-
- }
- // 模块卸载函数
- void light_cleanup(void)
- {
- unregister_chrdev(major,NAME);
- printk("Goodbye,cruel world!\n");
- }
- module_init(light_init);
- module_exit(light_cleanup);
应用程序:
- #include <stdlib.h>
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <fcntl.h>
- #include <linux/input.h>
- #include <unistd.h>
- #include <sys/ioctl.h>
- int main(int argc, char * argv)
- {
- int i, n, fd;
- fd = open("/dev/leds", O_RDWR);
- if (fd < 0)
- {
- printf("can't open /dev/leds!\n");
- exit(1);
- }
- while (1) {
- ioctl(fd, 1, 1);
- sleep(1);
- ioctl(fd, 0, 1);
- sleep(1);
- }
- close(fd);
- return 0;
- }
Makefile文件:
- ARCH=arm
- CROSS_COMPILE=/home/chenzhufly/beaglebone/linux-devkit/bin/arm-arago-linux-gnueabi-
- obj-m := leds.o
- KDIR := /home/chenzhufly/beaglebone/board-support/linux-3.1.0-psp04.06.00.03.sdk
- PWD := $(shell pwd)
- default:
- make -C $(KDIR) M=$(PWD) ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) modules
- app: leds_test.c
- $(CROSS_COMPILE)gcc -o leds_test leds_test.c
- clean:
- $(MAKE) -C $(KDIR) M=$(PWD) clean
leds.sh脚本- insmod leds.ko
- mknod /dev/leds c 251 0
- ./leds_test
2. 使用echo命令,这个我在前面也说过
- 点亮usr1
- root@beaglebone:~# echo 1 >
- /sys/class/leds/beaglebone::usr1/brightness
- 关闭usr1
- root@beaglebone:~# echo 0 > /sys/class/leds/beaglebone::usr1/brightness
3. 做个应用程序实现流水灯功能吧
- #include <stdio.h>
- #include <unistd.h>
- #include <sys/types.h>
- #include <sys/ipc.h>
- #include <sys/ioctl.h>
- #include <fcntl.h>
- #define LED1 "/sys/class/leds/beaglebone::usr1/brightness" // usr1 led
- #define LED2 "/sys/class/leds/beaglebone::usr2/brightness" // usr2 led
- #define LED3 "/sys/class/leds/beaglebone::usr3/brightness" // usr3 led
- int main(void)
- {
- int f_led1 = open(LED1, O_RDWR);
- int f_led2 = open(LED2, O_RDWR);
- int f_led3 = open(LED3, O_RDWR);
-
- unsigned char dat1, dat2, dat3;
- unsigned char i = 0;
-
- if (f_led1 < 0)
- {
- printf("error in open %s",LED1);
- return -1;
- }
- if (f_led2 < 0)
- {
- printf("error in open %s",LED2);
- return -1;
- }
- if (f_led3 < 0)
- {
- printf("error in open %s",LED3);
- return -1;
- }
- //add 10 times
- for(i=1; i<30; i++)
- {
- dat1 = ((i%3) == 1) ? '1' : '0';
- dat2 = ((i%3) == 2) ? '1' : '0';
- dat3 = ((i%3) == 0) ? '1' : '0';
- write(f_led1, &dat1, sizeof(dat1));
- write(f_led2, &dat2, sizeof(dat2));
- write(f_led3, &dat3, sizeof(dat3));
- usleep(300000);
- }
- // all the bright
- {
- dat1 = '1';
- dat2 = '1';
- dat3 = '1';
- write(f_led1, &dat1, sizeof(dat1));
- write(f_led2, &dat2, sizeof(dat2));
- write(f_led3, &dat3, sizeof(dat3));
- }
- }
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