On Fri, 2013-08-16 at 22:25 +0200, Yann Cantin wrote:

> +/* IRQ */
> +static int ebeam_read_data(struct ebeam_device *ebeam, unsigned char *pkt)
> +{
> +
> +/*
> + * Packet description : 8 bytes
> + *
> + *  nop packet : FF FF FF FF FF FF FF FF
> + *
> + *  pkt[0] : Sensors
> + *   bit 1 : ultrasound signal (guessed)
> + *   bit 2 : IR signal (tested with a remote...) ;
> + *   readings OK : 0x03 (anything else is a show-stopper)
> + *
> + *  pkt[1] : raw_x low
> + *  pkt[2] : raw_x high
> + *
> + *  pkt[3] : raw_y low
> + *  pkt[4] : raw_y high
> + *
> + *  pkt[5] : fiability ?
> + *   often 0xC0
> + *   > 0x80 : OK
> + *
> + *  pkt[6] :
> + *   buttons state (low 4 bits)
> + *           0x1 = no buttons
> + *           bit 0 : tip (WARNING inversed : 0=pressed)
> + *           bit 1 : ? (always 0 during tests)
> + *           bit 2 : little (1=pressed)
> + *           bit 3 : big (1=pressed)
> + *
> + *   pointer ID : (high 4 bits)
> + *           Tested  : 0x6=wand ;
> + *           Guessed : 0x1=red ; 0x2=blue ; 0x3=green ; 0x4=black ;
> + *                     0x5=eraser
> + *           bit 4 : pointer ID
> + *           bit 5 : pointer ID
> + *           bit 6 : pointer ID
> + *           bit 7 : pointer ID
> + *
> + *
> + *  pkt[7] : fiability ?
> + *   often 0xFF
> + *
> + */
> +
> +     /* Filtering bad/nop packet */
> +     if (pkt[0] != 0x03)
> +             return 0;
> +
> +     ebeam->raw_x = (pkt[2] << 8) | pkt[1];
> +     ebeam->raw_y = (pkt[4] << 8) | pkt[3];

We have macros. In this case get_unaligned_le16.

> +     ebeam->btn_map = (!(pkt[6] & 0x1))      |
> +                      ((pkt[6] & 0x4) >> 1)  |
> +                      ((pkt[6] & 0x8) >> 1);
> +
> +     return 1;
> +}


> +static void ebeam_close(struct input_dev *input)
> +{
> +     struct ebeam_device *ebeam = input_get_drvdata(input);
> +     int r;
> +
> +     usb_kill_urb(ebeam->irq);
> +
> +     r = usb_autopm_get_interface(ebeam->interface);

Nope. That's an uncool race. If the interface is suspended when
you call this, you will resume it and restart the URB. Therefore
you ought to kill the URB after resuming.

> +     ebeam->interface->needs_remote_wakeup = 0;
> +
> +     if (!r)
> +             usb_autopm_put_interface(ebeam->interface);
> +}
> +
> +static int ebeam_suspend(struct usb_interface *intf, pm_message_t message)
> +{
> +     struct ebeam_device *ebeam = usb_get_intfdata(intf);
> +
> +     usb_kill_urb(ebeam->irq);
> +
> +     return 0;
> +}
> +
> +static int ebeam_resume(struct usb_interface *intf)
> +{
> +     struct ebeam_device *ebeam = usb_get_intfdata(intf);
> +     struct input_dev *input = ebeam->input;
> +     int result = 0;
> +
> +     mutex_lock(&input->mutex);
> +     if (input->users)
> +             result = usb_submit_urb(ebeam->irq, GFP_NOIO);
> +     mutex_unlock(&input->mutex);
> +
> +     return result;
> +}
> +
> +static int ebeam_reset_resume(struct usb_interface *intf)
> +{
> +     return ebeam_resume(intf);
> +}

No need to define a function. You can use the function as
value for resume and reset_resume.

> +
> +static int ebeam_probe(struct usb_interface *intf,
> +                    const struct usb_device_id *id)
> +{
> +     struct ebeam_device *ebeam;
> +     struct input_dev *input_dev;
> +     struct usb_endpoint_descriptor *endpoint;
> +     struct usb_device *udev = interface_to_usbdev(intf);
> +     int err = -ENOMEM;
> +
> +     endpoint = ebeam_get_input_endpoint(intf->cur_altsetting);
> +     if (!endpoint)
> +             return -ENXIO;
> +
> +     ebeam = kzalloc(sizeof(struct ebeam_device), GFP_KERNEL);
> +     input_dev = input_allocate_device();
> +     if (!ebeam || !input_dev)
> +             goto out_free;
> +
> +     ebeam_init_settings(ebeam);
> +
> +     ebeam->data = usb_alloc_coherent(udev, REPT_SIZE,
> +                                      GFP_KERNEL, &ebeam->data_dma);
> +     if (!ebeam->data)
> +             goto out_free;
> +
> +     ebeam->irq = usb_alloc_urb(0, GFP_KERNEL);
> +     if (!ebeam->irq) {
> +             dev_dbg(&intf->dev,
> +                     "%s - usb_alloc_urb failed: ebeam->irq\n", __func__);
> +             goto out_free_buffers;
> +     }
> +
> +     ebeam->interface = intf;
> +     ebeam->input = input_dev;
> +
> +     /* setup name */
> +     snprintf(ebeam->name, sizeof(ebeam->name),
> +              "USB eBeam %04x:%04x",
> +              le16_to_cpu(udev->descriptor.idVendor),
> +              le16_to_cpu(udev->descriptor.idProduct));
> +
> +     if (udev->manufacturer || udev->product) {
> +             strlcat(ebeam->name,
> +                     " (",
> +                     sizeof(ebeam->name));
> +
> +             if (udev->manufacturer)
> +                     strlcat(ebeam->name,
> +                             udev->manufacturer,
> +                             sizeof(ebeam->name));
> +
> +             if (udev->product) {
> +                     if (udev->manufacturer)
> +                             strlcat(ebeam->name,
> +                                     " ",
> +                                     sizeof(ebeam->name));
> +                     strlcat(ebeam->name,
> +                             udev->product,
> +                             sizeof(ebeam->name));
> +             }
> +
> +             if (strlcat(ebeam->name, ")", sizeof(ebeam->name))
> +                     >= sizeof(ebeam->name)) {
> +                     /* overflowed, closing ) anyway */
> +                     ebeam->name[sizeof(ebeam->name)-2] = ')';
> +             }
> +     }
> +
> +     /* usb tree */
> +     usb_make_path(udev, ebeam->phys, sizeof(ebeam->phys));
> +     strlcat(ebeam->phys, "/input0", sizeof(ebeam->phys));
> +
> +     /* input setup */
> +     input_dev->name = ebeam->name;
> +     input_dev->phys = ebeam->phys;
> +     usb_to_input_id(udev, &input_dev->id);
> +     input_dev->dev.parent = &intf->dev;
> +
> +     input_set_drvdata(input_dev, ebeam);
> +
> +     input_dev->open = ebeam_open;
> +     input_dev->close = ebeam_close;
> +
> +     /* usb urb setup */
> +     if (usb_endpoint_type(endpoint) == USB_ENDPOINT_XFER_INT)
> +             usb_fill_int_urb(ebeam->irq, udev,
> +                     usb_rcvintpipe(udev, endpoint->bEndpointAddress),
> +                     ebeam->data, REPT_SIZE,
> +                     ebeam_irq, ebeam, endpoint->bInterval);
> +     else
> +             usb_fill_bulk_urb(ebeam->irq, udev,
> +                     usb_rcvbulkpipe(udev, endpoint->bEndpointAddress),
> +                     ebeam->data, REPT_SIZE,
> +                     ebeam_irq, ebeam);
> +
> +     ebeam->irq->dev = udev;
> +     ebeam->irq->transfer_dma = ebeam->data_dma;
> +     ebeam->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
> +
> +     /* input final setup */
> +     ebeam_setup_input(ebeam, input_dev);
> +
> +     err = input_register_device(ebeam->input);
> +     if (err) {
> +             dev_dbg(&intf->dev,
> +                     "%s - input_register_device failed, err: %d\n",
> +                     __func__, err);
> +             goto out_free_urb;
> +     }
> +
> +     /* usb final setup */
> +     usb_set_intfdata(intf, ebeam);
> +
> +     /* sysfs setup */
> +     err = sysfs_create_group(&intf->dev.kobj, &ebeam_attr_group);
> +     if (err) {
> +             dev_dbg(&intf->dev,
> +                     "%s - cannot create sysfs group, err: %d\n",
> +                     __func__, err);
> +             goto out_unregister_input;
> +     }

This is not nice. User space may react to a new input device of this
type by setting up the calibration. But the sysfs files may be created
after that. You should invert the order.

        HTH
                Oliver


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