USB驱动——鼠标驱动程序（中断传输）

USB驱动——鼠标驱动程序（中断传输）

http://blog.csdn.net/lizuobin2/ https://blog.csdn.net/lizuobin2/article/details/51969817

    本文以 usbmouse.c 为例，简单分析usb鼠标驱动程序。

1. static int __init usb_mouse_init(void)

2. {

3. int retval = usb_register(&usb_mouse_driver);

4. if (retval == 0)

5. printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"

6. DRIVER_DESC "\n");

7. return retval;

8. }

    使用 usb_register 注册到内核的驱动程序都是对应于一个usb设备的接口（逻辑设备）。

1. static struct usb_driver usb_mouse_driver = {

2. .name = "usbmouse",

3. .probe = usb_mouse_probe,

4. .disconnect = usb_mouse_disconnect,

5. .id_table = usb_mouse_id_table,

6. };

    id_table 中指明了这个驱动程序支持哪些类型的接口

1. static struct usb_device_id usb_mouse_id_table [] = {

2. { USB_INTERFACE_INFO(USB_INTERFACE_CLASS_HID, USB_INTERFACE_SUBCLASS_BOOT,

3. USB_INTERFACE_PROTOCOL_MOUSE) },

4. { } /* Terminating entry */

5. };

    USB_INTERFACE_INFO ，通过接口信息来匹配，内核里还有一些其它的宏，例如 USB_DEVICE ，使用它可以根据厂商ID、设备ID来匹配，让你的驱动程序仅仅支持某一个厂家的某一款设备。还有一些其它的匹配方法不再赘述。

    匹配成功之后，便会调用 probe 函数。

1. static int usb_mouse_probe(struct usb_interface *intf, const struct usb_device_id *id)

2. {

3. /* 得到设备 */

4. struct usb_device *dev = interface_to_usbdev(intf);

5.  

6. /* 一个接口的当前设置 */

7. struct usb_host_interface *interface;

8.  

9. /* 端点描述符 */

10. struct usb_endpoint_descriptor *endpoint;

11.  

12. struct usb_mouse *mouse;

13.  

14. /* 输入设备 */

15. struct input_dev *input_dev;

16. int pipe, maxp;

17. int error = -ENOMEM;

18.  

19. /* 获取接口的当前设置 */

20. interface = intf->cur_altsetting;

21.  

22. /* 获得当前设置的第一个端点的描述符，usb鼠标除了端点0就这一个端点 */

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

24.  

25. /* 获得端点对应的管道 */

26. pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);

27.  

28. /* 返回这个端点的传输最大包大小 */

29. maxp = usb_maxpacket(dev, pipe, usb_pipeout(pipe));

30.  

31. /* 输入子系统 */

32. input_dev = input_allocate_device();

33.  

34. /* 用一个 usb_mouse 结构来保存 urb buffer irq 等信息 */

35. mouse = kzalloc(sizeof(struct usb_mouse), GFP_KERNEL);

36.  

37. /* 分配空间 */

38. mouse->data = usb_buffer_alloc(dev, 8, GFP_ATOMIC, &mouse->data_dma);

39.  

40. /* 分配urb */

41. mouse->irq = usb_alloc_urb(0, GFP_KERNEL);

42.  

43. mouse->usbdev = dev;

44. mouse->dev = input_dev;

45.  

46. /* 一些设备信息的拷贝，无关紧要 */

47. if (dev->manufacturer)

48. strlcpy(mouse->name, dev->manufacturer, sizeof(mouse->name));

49.  

50. if (dev->product) {

51. if (dev->manufacturer)

52. strlcat(mouse->name, " ", sizeof(mouse->name));

53. strlcat(mouse->name, dev->product, sizeof(mouse->name));

54. }

55.  

56. if (!strlen(mouse->name))

57. snprintf(mouse->name, sizeof(mouse->name),

58. "USB HIDBP Mouse %04x:%04x",

59. le16_to_cpu(dev->descriptor.idVendor),

60. le16_to_cpu(dev->descriptor.idProduct));

61.  

62. usb_make_path(dev, mouse->phys, sizeof(mouse->phys));

63. strlcat(mouse->phys, "/input0", sizeof(mouse->phys));

64.  

65. /* 输入子系统的一些设置 */

66. input_dev->name = mouse->name;

67. input_dev->phys = mouse->phys;

68. usb_to_input_id(dev, &input_dev->id);

69. input_dev->dev.parent = &intf->dev;

70.  

71. /* 设置支持哪些类型的事件。以及那些事件 */

72. input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);

73. input_dev->keybit[BIT_WORD(BTN_MOUSE)] = BIT_MASK(BTN_LEFT) |

74. BIT_MASK(BTN_RIGHT) | BIT_MASK(BTN_MIDDLE);

75. input_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y);

76. input_dev->keybit[BIT_WORD(BTN_MOUSE)] |= BIT_MASK(BTN_SIDE) |

77. BIT_MASK(BTN_EXTRA);

78. input_dev->relbit[0] |= BIT_MASK(REL_WHEEL);

79.  

80. input_set_drvdata(input_dev, mouse);

81.  

82. /* 输入设备的Open close 函数，open函数中会提交urb */

83. input_dev->open = usb_mouse_open;

84. input_dev->close = usb_mouse_close;

85.  

86. /* 填充中断传输类型的urb */

87. usb_fill_int_urb(mouse->irq, dev, pipe, mouse->data,

88. (maxp > 8 ? 8 : maxp),

89. usb_mouse_irq, mouse, endpoint->bInterval);

90. mouse->irq->transfer_dma = mouse->data_dma;

91. mouse->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

92.  

93. /* 注册输入设备 */

94. error = input_register_device(mouse->dev);

95.  

96. usb_set_intfdata(intf, mouse);

97. return 0;

98. }

1. static int usb_mouse_open(struct input_dev *dev)

2. {

3. struct usb_mouse *mouse = input_get_drvdata(dev);

4.  

5. mouse->irq->dev = mouse->usbdev;

6. if (usb_submit_urb(mouse->irq, GFP_KERNEL))

7. return -EIO;

8.  

9. return 0;

10. }

    open 输入设备的时候，urb 就被提交了。每次鼠标有信息要提交给usb主机时，就会调用到 

1. static void usb_mouse_irq(struct urb *urb)

2. {

3. struct usb_mouse *mouse = urb->context;

4. signed char *data = mouse->data;

5. struct input_dev *dev = mouse->dev;

6. int status;

7.  

8. switch (urb->status) {

9. case 0: /* success */

10. break;

11. case -ECONNRESET: /* unlink */

12. case -ENOENT:

13. case -ESHUTDOWN:

14. return;

15. /* -EPIPE: should clear the halt */

16. default: /* error */

17. goto resubmit;

18. }

19. /* 根据data里的内容，上报不同事件 */

20. input_report_key(dev, BTN_LEFT, data[0] & 0x01);

21. input_report_key(dev, BTN_RIGHT, data[0] & 0x02);

22. input_report_key(dev, BTN_MIDDLE, data[0] & 0x04);

23. input_report_key(dev, BTN_SIDE, data[0] & 0x08);

24. input_report_key(dev, BTN_EXTRA, data[0] & 0x10);

25.  

26. input_report_rel(dev, REL_X, data[1]);

27. input_report_rel(dev, REL_Y, data[2]);

28. input_report_rel(dev, REL_WHEEL, data[3]);

29.  

30. input_sync(dev);

31. resubmit:

32. status = usb_submit_urb (urb, GFP_ATOMIC);// 重新提交 urb

33. if (status)

34. err ("can't resubmit intr, %s-%s/input0, status %d",

35. mouse->usbdev->bus->bus_name,

36. mouse->usbdev->devpath, status);

37. }