arm 驱动进阶：驱动程序总线设备驱动模型
总线设备驱动模型关系图：
驱动程序总线设备驱动模型代码编写步骤：
device、driver、app led驱动实例：
device代码实现：
led_drv.c
#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[] = { [0] = { .start = 0x56000050, .end = 0x56000050 + 8 - 1, .flags = IORESOURCE_MEM, }, [1] = { .start = 5, .end = 5, .flags = IORESOURCE_IRQ, } }; static void led_release(struct device * dev) { } static struct platform_device led_dev = { .name = "myled", .id = -1, .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 0; } static void led_dev_exit(void) { platform_device_unregister(&led_dev); } module_init(led_dev_init); module_exit(led_dev_exit); MODULE_LICENSE("GPL");
driver代码实现：
led_drv.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*2)); *gpio_con |= (0x1<<(pin*2)); return 0; } 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 == 1) { // 点灯 *gpio_dat &= ~(1<<pin); } else { // 灭灯 *gpio_dat |= (1<<pin); } return 0; } 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, 0); gpio_con = ioremap(res->start, res->end - res->start + 1); gpio_dat = gpio_con + 1; res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); pin = res->start; /* 注册字符设备驱动程序 */ printk("led_probe, found led\n"); major = register_chrdev(0, "myled", &led_fops); cls = class_create(THIS_MODULE, "myled"); class_device_create(cls, NULL, MKDEV(major, 0), NULL, "led"); /* /dev/led */ return 0; } 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, 0)); class_destroy(cls); unregister_chrdev(major, "myled"); iounmap(gpio_con); return 0; } 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 0; } static void led_drv_exit(void) { platform_driver_unregister(&led_drv); } module_init(led_drv_init); module_exit(led_drv_exit); MODULE_LICENSE("GPL");
app代码实现：
led_test.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 = 1; fd = open("/dev/led", O_RDWR); if (fd < 0) { printf("can't open!\n"); } if (argc != 2) { printf("Usage :\n"); printf("%s <on|off>\n", argv[0]); return 0; } if (strcmp(argv[1], "on") == 0) { val = 1; } else { val = 0; } write(fd, &val, 4); return 0; }