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Date: Wed, 21 Aug 2013 07:25:50 +0200
From: Oliver Neukum <oliver@...kum.org>
To: Yann Cantin <yann.cantin@...oste.net>
Cc: linux-input@...r.kernel.org, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
dmitry.torokhov@...il.com, jkosina@...e.cz, rob@...dley.net,
gregkh@...uxfoundation.org
Subject: Re: [PATCH 2/2] input: misc: New USB eBeam input driver
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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