kbtab.c

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

/*
 * Version Information
 * v0.0.1 - Original, extremely basic version, 2.4.xx only
 * v0.0.2 - Updated, works with 2.5.62 and 2.4.20;
 *           - added pressure-threshold modules param code from
 *              Alex Perry <[email protected]>
 */

#define DRIVER_VERSION "v0.0.2"
#define DRIVER_AUTHOR "Josh Myer <[email protected]>"
#define DRIVER_DESC "USB KB Gear JamStudio Tablet driver"
#define DRIVER_LICENSE "GPL"

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE(DRIVER_LICENSE);

#define USB_VENDOR_ID_KBGEAR    0x084e

static int kb_pressure_click = 0x10;
module_param(kb_pressure_click, int, 0);
MODULE_PARM_DESC(kb_pressure_click, "pressure threshold for clicks");

struct kbtab {
    unsigned char *data;
    dma_addr_t data_dma;
    struct input_dev *dev;
    struct usb_device *usbdev;
    struct usb_interface *intf;
    struct urb *irq;
    char phys[32];
};

static void kbtab_irq(struct urb *urb)
{
    struct kbtab *kbtab = urb->context;
    unsigned char *data = kbtab->data;
    struct input_dev *dev = kbtab->dev;
    int pressure;
    int retval;

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


    input_report_key(dev, BTN_TOOL_PEN, 1);

    input_report_abs(dev, ABS_X, get_unaligned_le16(&data[1]));
    input_report_abs(dev, ABS_Y, get_unaligned_le16(&data[3]));

    /*input_report_key(dev, BTN_TOUCH , data[0] & 0x01);*/
    input_report_key(dev, BTN_RIGHT, data[0] & 0x02);

    pressure = data[5];
    if (kb_pressure_click == -1)
        input_report_abs(dev, ABS_PRESSURE, pressure);
    else
        input_report_key(dev, BTN_LEFT, pressure > kb_pressure_click ? 1 : 0);

    input_sync(dev);

 exit:
    retval = usb_submit_urb(urb, GFP_ATOMIC);
    if (retval)
        dev_err(&kbtab->intf->dev,
            "%s - usb_submit_urb failed with result %d\n",
            __func__, retval);
}

static struct usb_device_id kbtab_ids[] = {
    { USB_DEVICE(USB_VENDOR_ID_KBGEAR, 0x1001), .driver_info = 0 },
    { }
};

MODULE_DEVICE_TABLE(usb, kbtab_ids);

static int kbtab_open(struct input_dev *dev)
{
    struct kbtab *kbtab = input_get_drvdata(dev);

    kbtab->irq->dev = kbtab->usbdev;
    if (usb_submit_urb(kbtab->irq, GFP_KERNEL))
        return -EIO;

    return 0;
}

static void kbtab_close(struct input_dev *dev)
{
    struct kbtab *kbtab = input_get_drvdata(dev);

    usb_kill_urb(kbtab->irq);
}

static int kbtab_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
    struct usb_device *dev = interface_to_usbdev(intf);
    struct usb_endpoint_descriptor *endpoint;
    struct kbtab *kbtab;
    struct input_dev *input_dev;
    int error = -ENOMEM;

    kbtab = kzalloc(sizeof(struct kbtab), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!kbtab || !input_dev)
        goto fail1;

    kbtab->data = usb_alloc_coherent(dev, 8, GFP_KERNEL, &kbtab->data_dma);
    if (!kbtab->data)
        goto fail1;

    kbtab->irq = usb_alloc_urb(0, GFP_KERNEL);
    if (!kbtab->irq)
        goto fail2;

    kbtab->usbdev = dev;
    kbtab->intf = intf;
    kbtab->dev = input_dev;

    usb_make_path(dev, kbtab->phys, sizeof(kbtab->phys));
    strlcat(kbtab->phys, "/input0", sizeof(kbtab->phys));

    input_dev->name = "KB Gear Tablet";
    input_dev->phys = kbtab->phys;
    usb_to_input_id(dev, &input_dev->id);
    input_dev->dev.parent = &intf->dev;

    input_set_drvdata(input_dev, kbtab);

    input_dev->open = kbtab_open;
    input_dev->close = kbtab_close;

    input_dev->evbit[0] |= BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
    input_dev->keybit[BIT_WORD(BTN_LEFT)] |=
        BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_RIGHT);
    input_dev->keybit[BIT_WORD(BTN_DIGI)] |=
        BIT_MASK(BTN_TOOL_PEN) | BIT_MASK(BTN_TOUCH);
    input_set_abs_params(input_dev, ABS_X, 0, 0x2000, 4, 0);
    input_set_abs_params(input_dev, ABS_Y, 0, 0x1750, 4, 0);
    input_set_abs_params(input_dev, ABS_PRESSURE, 0, 0xff, 0, 0);

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

    usb_fill_int_urb(kbtab->irq, dev,
             usb_rcvintpipe(dev, endpoint->bEndpointAddress),
             kbtab->data, 8,
             kbtab_irq, kbtab, endpoint->bInterval);
    kbtab->irq->transfer_dma = kbtab->data_dma;
    kbtab->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

    error = input_register_device(kbtab->dev);
    if (error)
        goto fail3;

    usb_set_intfdata(intf, kbtab);

    return 0;

 fail3: usb_free_urb(kbtab->irq);
 fail2: usb_free_coherent(dev, 8, kbtab->data, kbtab->data_dma);
 fail1: input_free_device(input_dev);
    kfree(kbtab);
    return error;
}

static void kbtab_disconnect(struct usb_interface *intf)
{
    struct kbtab *kbtab = usb_get_intfdata(intf);

    usb_set_intfdata(intf, NULL);

    input_unregister_device(kbtab->dev);
    usb_free_urb(kbtab->irq);
    usb_free_coherent(kbtab->usbdev, 8, kbtab->data, kbtab->data_dma);
    kfree(kbtab);
}

static struct usb_driver kbtab_driver = {
    .name =     "kbtab",
    .probe =    kbtab_probe,
    .disconnect =   kbtab_disconnect,
    .id_table = kbtab_ids,
};

module_usb_driver(kbtab_driver);