下面以一个按键的实验作为驱动分离时间简单学习：
#include <linux/module.h>
#include <linux/version.h> #include <linux/init.h> #include <linux/kernel.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/timer.h>
#include <linux/init.h>
#include <linux/serial_core.h>
#include <linux/platform_device.h> /* 分配/设置/注册一个platform_device */ static struct resource led_resource[] = {
[] = {
.start = 0x56000050,
.end = 0x56000050 + - ,
.flags = IORESOURCE_MEM,
},
[] = {
.start = ,
.end = ,
.flags = IORESOURCE_IRQ,
} }; static void led_release(struct device * dev)
{
} static struct platform_device led_dev = {
.name = "myled",
.id = -,
.num_resources = ARRAY_SIZE(led_resource),
.resource = led_resource,
.dev = {
.release = led_release,
},
}; static int led_dev_init(void)
{
platform_device_register(&led_dev);
return ;
} static void led_dev_exit(void)
{
platform_device_unregister(&led_dev);
} module_init(led_dev_init);
module_exit(led_dev_exit); MODULE_LICENSE("GPL");
led_dev.c
/* 分配/设置/注册一个platform_driver */ #include <linux/module.h>
#include <linux/version.h> #include <linux/init.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/irq.h>
#include <asm/uaccess.h>
#include <asm/io.h> static int major; static struct class *cls;
static volatile unsigned long *gpio_con;
static volatile unsigned long *gpio_dat;
static int pin; static int led_open(struct inode *inode, struct file *file)
{
//printk("first_drv_open\n");
/* 配置为输出 */
*gpio_con &= ~(0x3<<(pin*));
*gpio_con |= (0x1<<(pin*));
return ;
} static ssize_t led_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
{
int val; //printk("first_drv_write\n"); copy_from_user(&val, buf, count); // copy_to_user(); if (val == )
{
// 点灯
*gpio_dat &= ~(<<pin);
}
else
{
// 灭灯
*gpio_dat |= (<<pin);
} return ;
} static struct file_operations led_fops = {
.owner = THIS_MODULE, /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */
.open = led_open,
.write = led_write,
}; static int led_probe(struct platform_device *pdev)
{
struct resource *res; /* 根据platform_device的资源进行ioremap */
res = platform_get_resource(pdev, IORESOURCE_MEM, );
gpio_con = ioremap(res->start, res->end - res->start + );
gpio_dat = gpio_con + ; res = platform_get_resource(pdev, IORESOURCE_IRQ, );
pin = res->start; /* 注册字符设备驱动程序 */ printk("led_probe, found led\n"); major = register_chrdev(, "myled", &led_fops); cls = class_create(THIS_MODULE, "myled"); class_device_create(cls, NULL, MKDEV(major, ), NULL, "led"); /* /dev/led */ return ;
} static int led_remove(struct platform_device *pdev)
{
/* 卸载字符设备驱动程序 */
/* iounmap */
printk("led_remove, remove led\n"); class_device_destroy(cls, MKDEV(major, ));
class_destroy(cls);
unregister_chrdev(major, "myled");
iounmap(gpio_con); return ;
} struct platform_driver led_drv = {
.probe = led_probe,
.remove = led_remove,
.driver = {
.name = "myled",
}
}; static int led_drv_init(void)
{
platform_driver_register(&led_drv);
return ;
} static void led_drv_exit(void)
{
platform_driver_unregister(&led_drv);
} module_init(led_drv_init);
module_exit(led_drv_exit); MODULE_LICENSE("GPL");
led_drv.c
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h> /* led_test on
* led_test off
*/
int main(int argc, char **argv)
{
int fd;
int val = ;
fd = open("/dev/led", O_RDWR);
if (fd < )
{
printf("can't open!\n");
}
if (argc != )
{
printf("Usage :\n");
printf("%s <on|off>\n", argv[]);
return ;
} if (strcmp(argv[], "on") == )
{
val = ;
}
else
{
val = ;
} write(fd, &val, );
return ;
}
led_test.c