驱动程序分层分离概念--总线驱动设备模型

一、示意图

                  App
--------------------------------------------------
               input.c
--------------------------------------------------
           /
          /
         /       分离
button.c       < ===== >   evdev.c
硬件相关                  纯软件(稳定)

-----------------------------------------------

bus_drv_dev模型                           bus drv链表
1.把device放入bus的dev链表      device_add /.match 1.放入drv链表 2.从dv链表取出一一比较（match）
2.从bus的drv链表取出每一个drv              /         driver_register
用bus的match函数判断drv能否支持dev        /           3.若支持，调用probe
3.若可以支持，调用drv的probe           device       driver
                                    硬件相关      .probe比较稳定的代码
                                                 .name

-----------------------------------------------
                 usb_bus_type
                /
usb_new_device /              usb_register
              /
usb_interface                  usb_driver
                               .id_table
                               .probe

-----------------------------------------------
        platform_bus_type
      /     .match　　
   /
    /　　　　　　　　　　　　
platform_device       platform_driver
                        .probe

-----------------------------------------------

二、led_dev.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");

三、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 ");
   /* 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 ");

   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 ");

   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 ");

   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");

四、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! ");
   }
   if (argc != 2)
   {
       printf("Usage : ");
       printf("%s <on|off> ", argv[0]);
       return 0;
   }

   if (strcmp(argv[1], "on") == 0)
   {
       val = 1;
   }
   else
   {
       val = 0;
   }

   write(fd, &val, 4);
   return 0;
}
五、Makefile

KERN_DIR = /work/system/linux-2.6.22.6

all:
   make -C $(KERN_DIR) M=`pwd` modules

clean:
   make -C $(KERN_DIR) M=`pwd` modules clean
   rm -rf modules.order

obj-m   += led_drv.o
obj-m   += led_dev.o