drivers/input/tablet/acecad.c

Source file repositories/reference/linux-study-clean/drivers/input/tablet/acecad.c

File Facts

System
Linux kernel
Corpus path
drivers/input/tablet/acecad.c
Extension
.c
Size
6771 bytes
Lines
255
Domain
Driver Families
Bucket
drivers/input
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct usb_acecad {
	char name[128];
	char phys[64];
	struct usb_interface *intf;
	struct input_dev *input;
	struct urb *irq;

	unsigned char *data;
	dma_addr_t data_dma;
};

static void usb_acecad_irq(struct urb *urb)
{
	struct usb_acecad *acecad = urb->context;
	unsigned char *data = acecad->data;
	struct input_dev *dev = acecad->input;
	struct usb_interface *intf = acecad->intf;
	struct usb_device *udev = interface_to_usbdev(intf);
	int prox, status;

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dev_dbg(&intf->dev, "%s - urb shutting down with status: %d\n",
			__func__, urb->status);
		return;
	default:
		dev_dbg(&intf->dev, "%s - nonzero urb status received: %d\n",
			__func__, urb->status);
		goto resubmit;
	}

	prox = (data[0] & 0x04) >> 2;
	input_report_key(dev, BTN_TOOL_PEN, prox);

	if (prox) {
		int x = data[1] | (data[2] << 8);
		int y = data[3] | (data[4] << 8);
		/* Pressure should compute the same way for flair and 302 */
		int pressure = data[5] | (data[6] << 8);
		int touch = data[0] & 0x01;
		int stylus = (data[0] & 0x10) >> 4;
		int stylus2 = (data[0] & 0x20) >> 5;
		input_report_abs(dev, ABS_X, x);
		input_report_abs(dev, ABS_Y, y);
		input_report_abs(dev, ABS_PRESSURE, pressure);
		input_report_key(dev, BTN_TOUCH, touch);
		input_report_key(dev, BTN_STYLUS, stylus);
		input_report_key(dev, BTN_STYLUS2, stylus2);
	}

	/* event termination */
	input_sync(dev);

resubmit:
	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status)
		dev_err(&intf->dev,
			"can't resubmit intr, %s-%s/input0, status %d\n",
			udev->bus->bus_name,
			udev->devpath, status);
}

static int usb_acecad_open(struct input_dev *dev)
{
	struct usb_acecad *acecad = input_get_drvdata(dev);

	acecad->irq->dev = interface_to_usbdev(acecad->intf);
	if (usb_submit_urb(acecad->irq, GFP_KERNEL))
		return -EIO;

	return 0;
}

static void usb_acecad_close(struct input_dev *dev)
{
	struct usb_acecad *acecad = input_get_drvdata(dev);

	usb_kill_urb(acecad->irq);
}

static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
	struct usb_device *dev = interface_to_usbdev(intf);
	struct usb_host_interface *interface = intf->cur_altsetting;

Annotation

Implementation Notes