USB设备驱动程序学习笔记（二）

一、usbmouse_as_key.c

/*
* drivershidusbhidusbmouse.c
*/

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/usb/input.h>
#include <linux/hid.h>

static struct input_dev *uk_dev;
static char *usb_buf;
static dma_addr_t usb_buf_phys;
static int len;
static struct urb *uk_urb;

static struct usb_device_id usbmouse_as_key_id_table [] = {
   { USB_INTERFACE_INFO(USB_INTERFACE_CLASS_HID, USB_INTERFACE_SUBCLASS_BOOT,
       USB_INTERFACE_PROTOCOL_MOUSE) },
   //{USB_DEVICE(0x1234,0x5678)},
   { }   /* Terminating entry */
};

static void usbmouse_as_key_irq(struct urb *urb)
{
   static unsigned char pre_val;
#if 0
   int i;
   static int cnt = 0;
   printk("data cnt %d: ", ++cnt);
   for (i = 0; i < len; i++)
   {
       printk("%02x ", usb_buf[i]);
   }
   printk(" ");
#endif
   /* USB鼠标数据含义
   * data[0]: bit0-左键, 1-按下, 0-松开
   *          bit1-右键, 1-按下, 0-松开
   *          bit2-中键, 1-按下, 0-松开
   *
     */
   if ((pre_val & (1<<0)) != (usb_buf[0] & (1<<0)))
   {
       /* 左键发生了变化 */
       input_event(uk_dev, EV_KEY, KEY_L, (usb_buf[0] & (1<<0)) ? 1 : 0);
       input_sync(uk_dev);
   }

   if ((pre_val & (1<<1)) != (usb_buf[0] & (1<<1)))
   {
       /* 右键发生了变化 */
       input_event(uk_dev, EV_KEY, KEY_S, (usb_buf[0] & (1<<1)) ? 1 : 0);
       input_sync(uk_dev);
   }

   if ((pre_val & (1<<2)) != (usb_buf[0] & (1<<2)))
   {
       /* 中键发生了变化 */
       input_event(uk_dev, EV_KEY, KEY_ENTER, (usb_buf[0] & (1<<2)) ? 1 : 0);
       input_sync(uk_dev);
   }

   pre_val = usb_buf[0];

   /* 重新提交urb */
   usb_submit_urb(uk_urb, GFP_KERNEL);
}

static int usbmouse_as_key_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
   struct usb_device *dev = interface_to_usbdev(intf);
   struct usb_host_interface *interface;
   struct usb_endpoint_descriptor *endpoint;
   int pipe;

   interface = intf->cur_altsetting;
   endpoint = &interface->endpoint[0].desc;

   /* a. 分配一个input_dev */
   uk_dev = input_allocate_device();

   /* b. 设置 */
   /* b.1 能产生哪类事件 */
   set_bit(EV_KEY, uk_dev->evbit);
   set_bit(EV_REP, uk_dev->evbit);

   /* b.2 能产生哪些事件 */
   set_bit(KEY_L, uk_dev->keybit);
   set_bit(KEY_S, uk_dev->keybit);
   set_bit(KEY_ENTER, uk_dev->keybit);

   /* c. 注册 */
   input_register_device(uk_dev);

   /* d. 硬件相关操作 */
   /* 数据传输3要素: 源,目的,长度 */
   /* 源: USB设备的某个端点 */
   pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);

   /* 长度: */
   len = endpoint->wMaxPacketSize;

   /* 目的: */
   usb_buf = usb_buffer_alloc(dev, len, GFP_ATOMIC, &usb_buf_phys);

   /* 使用"3要素" */
   /* 分配usb request block */
   uk_urb = usb_alloc_urb(0, GFP_KERNEL);
   /* 使用"3要素设置urb" */
   usb_fill_int_urb(uk_urb, dev, pipe, usb_buf, len, usbmouse_as_key_irq, NULL, endpoint->bInterval);
   uk_urb->transfer_dma = usb_buf_phys;
   uk_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

   /* 使用URB */
   usb_submit_urb(uk_urb, GFP_KERNEL);

   return 0;
}

static void usbmouse_as_key_disconnect(struct usb_interface *intf)
{
   struct usb_device *dev = interface_to_usbdev(intf);

   //printk("disconnect usbmouse! ");
   usb_kill_urb(uk_urb);
   usb_free_urb(uk_urb);

   usb_buffer_free(dev, len, usb_buf, usb_buf_phys);
   input_unregister_device(uk_dev);
   input_free_device(uk_dev);
}

/* 1. 分配/设置usb_driver */
static struct usb_driver usbmouse_as_key_driver = {
   .name       = "usbmouse_as_key_",
   .probe       = usbmouse_as_key_probe,
   .disconnect   = usbmouse_as_key_disconnect,
   .id_table   = usbmouse_as_key_id_table,
};

static int usbmouse_as_key_init(void)
{
   /* 2. 注册 */
   usb_register(&usbmouse_as_key_driver);
   return 0;
}

static void usbmouse_as_key_exit(void)
{
   usb_deregister(&usbmouse_as_key_driver);
}

module_init(usbmouse_as_key_init);
module_exit(usbmouse_as_key_exit);

MODULE_LICENSE("GPL");

二、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   += usbmouse_as_key.o