usb-nrf2401_receive.c

USB2.0控制器CY7C68013在Ubuntu下的驱动程序

#include <linux/autoconf.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <asm/uaccess.h>
#include <linux/usb.h>


/* Define these values to match your devices */
#define USB_SKEL_VENDOR_ID	0x0547
#define USB_SKEL_PRODUCT_ID	0x1002

#define FRAMES_PER_DESC 10
#define ISO_PACKET_LEN 32

/* table of devices that work with this driver */
static struct usb_device_id skel_table [] = {
	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
	{ }					/* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, skel_table);


/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE	192

/* Structure to hold all of our device specific stuff */
struct usb_skel {
	struct usb_device *	udev;			/* the usb device for this device */
	struct usb_interface *	interface;		/* the interface for this device */
	unsigned char *		iso_in_buffer;		/* the buffer to receive data */
	size_t			iso_in_size;		/* the size of the receive buffer */
	__u8			iso_in_endpointAddr;	/* the address of the iso in endpoint */
	struct kref		kref;
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)

static struct usb_driver skel_driver;

static void skel_delete(struct kref *kref)
{	
	struct usb_skel *dev = to_skel_dev(kref);

	usb_put_dev(dev->udev);
	kfree (dev->iso_in_buffer);
	kfree (dev);
}

static int skel_open(struct inode *inode, struct file *file)
{
	struct usb_skel *dev;
	struct usb_interface *interface;
	int subminor;
	int retval = 0;

	subminor = iminor(inode);

	interface = usb_find_interface(&skel_driver, subminor);
	if (!interface) {
		err ("%s - error, can't find device for minor %d",
		     __FUNCTION__, subminor);
		retval = -ENODEV;
		goto exit;
	}

	dev = usb_get_intfdata(interface);
	if (!dev) {
		retval = -ENODEV;
		goto exit;
	}

	/* increment our usage count for the device */
	kref_get(&dev->kref);

	/* save our object in the file's private structure */
	file->private_data = dev;

exit:
	return retval;
}

static int skel_release(struct inode *inode, struct file *file)
{
	struct usb_skel *dev;

	dev = (struct usb_skel *)file->private_data;
	if (dev == NULL)
		return -ENODEV;

	/* decrement the count on our device */
	kref_put(&dev->kref, skel_delete);
	return 0;
}

static void skel_iso_callback(struct urb *urb, struct pt_regs *regs)
{
	struct usb_skel *dev;

	dev = (struct usb_skel *)urb->context;

	/* sync/async unlink faults aren't errors */
	if (urb->status && 
	    !(urb->status == -ENOENT || 
	      urb->status == -ECONNRESET ||
	      urb->status == -ESHUTDOWN)) {
		dbg("%s - nonzero write bulk status received: %d",
		    __FUNCTION__, urb->status);
	}

	/* free up our allocated buffer */
	usb_buffer_free(urb->dev, urb->transfer_buffer_length, 
			urb->transfer_buffer, urb->transfer_dma);
}

static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
{
	struct usb_skel *dev;
	int retval = 0;
	int j, k;
	struct urb *urb = NULL;
	
	dev = (struct usb_skel *)file->private_data;
	
	/* verify that we actually have some data to write */
	if (count == 0)
		goto exit;

	/* create a urb, and a buffer for it, and copy the data to the urb */
	urb = usb_alloc_urb(FRAMES_PER_DESC, GFP_KERNEL);
	if (!urb) {
		retval = -ENOMEM;
		goto error;
	}

	dev->iso_in_buffer = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
	if (!dev->iso_in_buffer) {
		retval = -ENOMEM;
		goto error;
	}
	
	/* initialize the urb properly */
	urb->dev = dev->udev;
	urb->context = dev;
	urb->pipe = usb_rcvisocpipe(dev->udev, dev->iso_in_endpointAddr);
	urb->interval = 1;
	urb->transfer_flags = URB_ISO_ASAP;
	urb->transfer_buffer = dev->iso_in_buffer;
	urb->complete = skel_iso_callback;
	urb->number_of_packets = FRAMES_PER_DESC;
	urb->transfer_buffer_length = ISO_PACKET_LEN * FRAMES_PER_DESC;
	for (j=k=0; j < FRAMES_PER_DESC; j++, k += ISO_PACKET_LEN) {
		urb->iso_frame_desc[j].offset = k;
		urb->iso_frame_desc[j].length = ISO_PACKET_LEN;
	}
		
	/* get the data in the iso port */
	retval = usb_submit_urb(urb, GFP_KERNEL);
	if (retval) {
		err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
		goto error;
	}

	/* if the read was successful, copy the data to userspace */
	if (!retval) {
		if (copy_to_user(buffer, dev->iso_in_buffer, urb->actual_length))
			retval = -EFAULT;
		else
			retval = urb->actual_length;
	}
	
	/* release our reference to this urb, the USB core will eventually free it entirely */
	usb_free_urb(urb);
	
exit:
	return count;

error:
	usb_buffer_free(dev->udev, count, dev->iso_in_buffer, urb->transfer_dma);
	usb_free_urb(urb);
	return retval;
}

static struct file_operations skel_fops = {
	.owner =	THIS_MODULE,
	.read =		skel_read,
	.open =		skel_open,
	.release =	skel_release,
};

/* 
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with devfs and the driver core
 */
static struct usb_class_driver skel_class = {
	.name =		"usb/skel%d",
	.fops =		&skel_fops,
	.minor_base =	USB_SKEL_MINOR_BASE,
};

static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
	struct usb_skel *dev = NULL;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	size_t buffer_size;
	int i;
	int retval = -ENOMEM;

	/* allocate memory for our device state and initialize it */
	dev = kmalloc(sizeof(*dev), GFP_KERNEL); 
	if (dev == NULL) {
		err("Out of memory");
		goto error;
	}
	memset(dev, 0x00, sizeof(*dev));
	kref_init(&dev->kref);

	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	dev->interface = interface;

	/* set up the endpoint information */
	/* use only the iso-in endpoint */
	iface_desc = interface->cur_altsetting;
	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
		endpoint = &iface_desc->endpoint[i].desc;

		if (!dev->iso_in_endpointAddr &&
		    (endpoint->bEndpointAddress & USB_DIR_IN) &&
		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
					== USB_ENDPOINT_XFER_ISOC)) {
			/* we found an iso in endpoint */
			buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
			dev->iso_in_size = buffer_size;
			dev->iso_in_endpointAddr = endpoint->bEndpointAddress;
			dev->iso_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
			if (!dev->iso_in_buffer) {
				err("Could not allocate iso_in_buffer");
				goto error;
			}
		}
	}	
	/* save our data pointer in this interface device */
	usb_set_intfdata(interface, dev);

	/* we can register the device now, as it is ready */
	retval = usb_register_dev(interface, &skel_class);
	if (retval) {
		/* something prevented us from registering this driver */
		err("Not able to get a minor for this device.");
		usb_set_intfdata(interface, NULL);
		goto error;
	}

	/* let the user know what node this device is now attached to */
	info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
	return 0;

error:
	if (dev)
		kref_put(&dev->kref, skel_delete);
	return retval;
}

static void skel_disconnect(struct usb_interface *interface)
{
	struct usb_skel *dev;
	int minor = interface->minor;

	/* prevent skel_open() from racing skel_disconnect() */
	lock_kernel();

	dev = usb_get_intfdata(interface);
	usb_set_intfdata(interface, NULL);

	/* give back our minor */
	usb_deregister_dev(interface, &skel_class);

	unlock_kernel();

	/* decrement our usage count */
	kref_put(&dev->kref, skel_delete);

	info("USB Skeleton #%d now disconnected", minor);
}

static struct usb_driver skel_driver = {
	.name =		"skeleton",
	.probe =	skel_probe,
	.disconnect =	skel_disconnect,
	.id_table =	skel_table,
};

static int __init usb_skel_init(void)
{
	int result;

	/* register this driver with the USB subsystem */
	result = usb_register(&skel_driver);
	if (result)
		err("usb_register failed. Error number %d", result);
	printk(KERN_ALERT "Entering myusb init\n"); 
	
	return result;
}

static void __exit usb_skel_exit(void)
{
	/* deregister this driver with the USB subsystem */
	usb_deregister(&skel_driver);
	printk(KERN_ALERT "Entering myusb exit\n"); 
}

module_init (usb_skel_init);
module_exit (usb_skel_exit);

MODULE_LICENSE("GPL");