比原来的好,结构体指针指向更细致了 还涉及内存管理,留下有时间好好学习研究一下
转自:
http://blog.sina.com.cn/s/blog_5f8665e70100pjtz.html
这段是mini2440的led Linux驱动程序代码
- #include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/poll.h>
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#include <linux/irq.h>
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#include <asm/irq.h>
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#include <linux/interrupt.h>
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#include <asm/uaccess.h>
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#include <mach/regs-gpio.h>
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#include <mach/hardware.h>
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#include <linux/platform_device.h>
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#include <linux/cdev.h>
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#include <linux/miscdevice.h>
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#include <linux/sched.h>
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#include <linux/gpio.h>
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#include <linux/slab.h>
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#define LED_MAJOR 0
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#define LED_ON 1
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#define LED_OFF 0
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struct led_dev {
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struct cdev cdev;
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unsigned char value;
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};
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struct led_dev *led_devp;
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static unsigned long led_table [] = {
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S3C2410_GPB(5),
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S3C2410_GPB(6),
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S3C2410_GPB(7),
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S3C2410_GPB(8),
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};
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static unsigned int led_cfg_table [] = {
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S3C2410_GPIO_OUTPUT,
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S3C2410_GPIO_OUTPUT,
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S3C2410_GPIO_OUTPUT,
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S3C2410_GPIO_OUTPUT,
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};
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int led_major = LED_MAJOR;
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int led_open(struct inode *inode, struct file *filp)
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{
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struct led_dev *dev;
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dev = container_of(inode->i_cdev, struct led_dev, cdev);
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filp->private_data = dev;
-
-
return 0;
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}
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int led_release(struct inode *inode, struct file *filp)
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{
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return 0;
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}
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ssize_t led_read(struct file *filp, char __user *buff, size_t count, loff_t *f_pos)
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{
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struct led_dev *dev = filp->private_data;
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-
if(copy_to_user(buff, &(dev->value), 1))
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return -EFAULT;
-
-
return 1;
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}
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ssize_t led_write(struct file *filp, const char __user *buff, size_t count, loff_t *f_pos)
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{
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struct led_dev *dev = filp->private_data;
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if(copy_from_user(&(dev->value), buff, 1))
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return -EFAULT;
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if(dev->value == 1)
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s3c2410_gpio_setpin(led_table[1], 0);
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else
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s3c2410_gpio_setpin(led_table[1], 1);
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return 1;
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}
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int led_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
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{
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struct led_dev *dev = filp->private_data;
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switch(cmd) {
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case LED_ON:
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dev->value = 1;
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s3c2410_gpio_setpin(led_table[arg], 0);
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break;
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case LED_OFF:
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dev->value = 0;
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s3c2410_gpio_setpin(led_table[arg], 1);
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break;
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default:
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return -ENOTTY;
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}
-
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return 0;
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}
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struct file_operations led_fops = {
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.owner = THIS_MODULE,
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.read = led_read,
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.write = led_write,
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.ioctl = led_ioctl,
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.open = led_open,
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.release = led_release,
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};
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static void led_setup_cdev(struct led_dev *dev, int index)
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{
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int err, devno = MKDEV(led_major, index);
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cdev_init(&dev->cdev, &led_fops);
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dev->cdev.owner = THIS_MODULE;
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dev->cdev.ops = &led_fops;
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err = cdev_add(&dev->cdev, devno, 1);
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if(err)
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printk(KERN_NOTICE "Error %d adding LED %d\n", err, index);
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}
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int led_init(void)
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{
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int result;
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int i;
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for (i = 0; i < 4; i++) {
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s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
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s3c2410_gpio_setpin(led_table[i], 0);
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}
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dev_t dev = MKDEV(led_major, 0);
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if(led_major)
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result = register_chrdev_region(dev, 1, "leds");
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else {
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result = alloc_chrdev_region(&dev, 0, 1, "leds");
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led_major = MAJOR(dev);
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}
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if(result < 0)
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return result;
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led_devp = kmalloc(sizeof(struct led_dev), GFP_KERNEL);
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if(!led_devp) {
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result = -ENOMEM;
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goto fail_malloc;
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}
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memset(led_devp, 0, sizeof(struct led_dev));
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led_setup_cdev(led_devp, 0);
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return 0;
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fail_malloc:
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unregister_chrdev_region(dev, 1);
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return result;
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}
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void led_exit(void)
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{
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cdev_del(&led_devp->cdev);
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kfree(led_devp);
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unregister_chrdev_region(MKDEV(led_major, 0), 1);
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}
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module_init(led_init);
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module_exit(led_exit);
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MODULE_AUTHOR("Jackie");
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MODULE_LICENSE("Dual BSD/GPL");
============================================================================================
以下是测试程序:
- #include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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int main(int argc, char **argv)
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{
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int on;
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int led_no;
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int fd;
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if(argc != 3 || sscanf(argv[1], "%d", &led_no) != 1 || sscanf(argv[2], "%d", &on) != 1
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|| on < 0 || on >1 || led_no < 0 || led_no >3) {
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fprintf(stderr, "Usage: leds led_no 0|1\n");
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exit(1);
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}
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fd = open("/dev/leds0", 0);
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if(fd < 0) {
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fd = open("/dev/leds", 0);
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}
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if(fd < 0) {
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perror("open device leds");
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exit(1);
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}
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ioctl(fd, on, led_no);
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close(fd);
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return 0;
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}
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