25、USB设备驱动开发详解

USB设备驱动开发详解

1. 遥测卡数据传输

在USB设备驱动开发中，遥测卡的数据传输是一个重要的部分。以下是相关的代码和操作流程。

首先是提交URB（USB请求块）的代码：

/* Submit the URB */
usb_submit_urb(tele_device->ctrl_urb, GFP_ATOMIC);
/* Wait until the callback returns indicating that the telemetry
   configuration register has been successfully initialized */
wait_for_completion(&tele_config_done);

/* Release our reference to the URB */
usb_free_urb(urb);
kfree(tmp);
/* Save the device-specific object to the file’s private_data 
   so that you can directly retrieve it from other entry points 
   such as tele_read() and tele_write() */
file->private_data = tele_device;
/* Return the URB transfer status */
return(tele_device->ctrl_urb->status);

这里使用了异步方式提交