From 3bc22dc66a4f386393119118169ed0b78c389898 Mon Sep 17 00:00:00 2001 From: Ricardo Ribalda Date: Tue, 20 Sep 2022 16:09:50 +0200 Subject: [PATCH] media: uvcvideo: Only create input devs if hw supports it Examine the stream headers to figure out if the device has a button and can be used as an input. Signed-off-by: Ricardo Ribalda Reviewed-by: Laurent Pinchart Signed-off-by: Laurent Pinchart --- drivers/media/usb/uvc/uvc_status.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c index 7518ffc..cb90aff 100644 --- a/drivers/media/usb/uvc/uvc_status.c +++ b/drivers/media/usb/uvc/uvc_status.c @@ -18,11 +18,34 @@ * Input device */ #ifdef CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV + +static bool uvc_input_has_button(struct uvc_device *dev) +{ + struct uvc_streaming *stream; + + /* + * The device has button events if both bTriggerSupport and + * bTriggerUsage are one. Otherwise the camera button does not + * exist or is handled automatically by the camera without host + * driver or client application intervention. + */ + list_for_each_entry(stream, &dev->streams, list) { + if (stream->header.bTriggerSupport == 1 && + stream->header.bTriggerUsage == 1) + return true; + } + + return false; +} + static int uvc_input_init(struct uvc_device *dev) { struct input_dev *input; int ret; + if (!uvc_input_has_button(dev)) + return 0; + input = input_allocate_device(); if (input == NULL) return -ENOMEM; -- 2.7.4