V4L/DVB (10242): pwc: add support for webcam snapshot button

This patch adds support for Philips webcam snapshot button as an
event input device, for consistency with other webcam drivers.
Signed-off-by: Pham Thanh Nam <phamthanhnam.ptn@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/pwc/Kconfig

@@ -35,3 +35,13 @@ config USB_PWC_DEBUG
 	  Say Y here in order to have the pwc driver generate verbose debugging
 	  messages.
 	  A special module options 'trace' is used to control the verbosity.
+
+config USB_PWC_INPUT_EVDEV
+	bool "USB Philips Cameras input events device support"
+	default y
+	depends on USB_PWC && INPUT
+	---help---
+	  This option makes USB Philips cameras register the snapshot button as
+	  an input device to report button events.
+
+	  If you are in doubt, say Y.

drivers/media/video/pwc/pwc-if.c

@@ -53,6 +53,7 @@
    - Xavier Roche: QuickCam Pro 4000 ID
    - Jens Knudsen: QuickCam Zoom ID
    - J. Debert: QuickCam for Notebooks ID
+   - Pham Thanh Nam: webcam snapshot button as an event input device
 */
 
 #include <linux/errno.h>
@@ -61,6 +62,9 @@
 #include <linux/module.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
+#ifdef CONFIG_USB_PWC_INPUT_EVDEV
+#include <linux/usb/input.h>
+#endif
 #include <linux/vmalloc.h>
 #include <asm/io.h>
 
@@ -586,6 +590,23 @@ static void pwc_frame_dumped(struct pwc_device *pdev)
 				pdev->vframe_count);
 }
 
+static void pwc_snapshot_button(struct pwc_device *pdev, int down)
+{
+	if (down) {
+		PWC_TRACE("Snapshot button pressed.\n");
+		pdev->snapshot_button_status = 1;
+	} else {
+		PWC_TRACE("Snapshot button released.\n");
+	}
+
+#ifdef CONFIG_USB_PWC_INPUT_EVDEV
+	if (pdev->button_dev) {
+		input_report_key(pdev->button_dev, BTN_0, down);
+		input_sync(pdev->button_dev);
+	}
+#endif
+}
+
 static int pwc_rcv_short_packet(struct pwc_device *pdev, const struct pwc_frame_buf *fbuf)
 {
 	int awake = 0;
@@ -603,13 +624,7 @@ static int pwc_rcv_short_packet(struct pwc_device *pdev, const struct pwc_frame_
 			pdev->vframes_error++;
 		}
 		if ((ptr[0] ^ pdev->vmirror) & 0x01) {
-			if (ptr[0] & 0x01) {
-				pdev->snapshot_button_status = 1;
-				PWC_TRACE("Snapshot button pressed.\n");
-			}
-			else {
-				PWC_TRACE("Snapshot button released.\n");
-			}
+			pwc_snapshot_button(pdev, ptr[0] & 0x01);
 		}
 		if ((ptr[0] ^ pdev->vmirror) & 0x02) {
 			if (ptr[0] & 0x02)
@@ -633,12 +648,7 @@ static int pwc_rcv_short_packet(struct pwc_device *pdev, const struct pwc_frame_
 	else if (pdev->type == 740 || pdev->type == 720) {
 		unsigned char *ptr = (unsigned char *)fbuf->data;
 		if ((ptr[0] ^ pdev->vmirror) & 0x01) {
-			if (ptr[0] & 0x01) {
-				pdev->snapshot_button_status = 1;
-				PWC_TRACE("Snapshot button pressed.\n");
-			}
-			else
-				PWC_TRACE("Snapshot button released.\n");
+			pwc_snapshot_button(pdev, ptr[0] & 0x01);
 		}
 		pdev->vmirror = ptr[0] & 0x03;
 	}
@@ -1216,6 +1226,15 @@ static void pwc_cleanup(struct pwc_device *pdev)
 {
 	pwc_remove_sysfs_files(pdev->vdev);
 	video_unregister_device(pdev->vdev);
+
+#ifdef CONFIG_USB_PWC_INPUT_EVDEV
+	if (pdev->button_dev) {
+		input_unregister_device(pdev->button_dev);
+		input_free_device(pdev->button_dev);
+		kfree(pdev->button_dev->phys);
+		pdev->button_dev = NULL;
+	}
+#endif
 }
 
 /* Note that all cleanup is done in the reverse order as in _open */
@@ -1483,6 +1502,9 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
 	int features = 0;
 	int video_nr = -1; /* default: use next available device */
 	char serial_number[30], *name;
+#ifdef CONFIG_USB_PWC_INPUT_EVDEV
+	char *phys = NULL;
+#endif
 
 	vendor_id = le16_to_cpu(udev->descriptor.idVendor);
 	product_id = le16_to_cpu(udev->descriptor.idProduct);
@@ -1807,6 +1829,35 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
 	pwc_set_leds(pdev, 0, 0);
 	pwc_camera_power(pdev, 0);
 
+#ifdef CONFIG_USB_PWC_INPUT_EVDEV
+	/* register webcam snapshot button input device */
+	pdev->button_dev = input_allocate_device();
+	if (!pdev->button_dev) {
+		PWC_ERROR("Err, insufficient memory for webcam snapshot button device.");
+		return -ENOMEM;
+	}
+
+	pdev->button_dev->name = "PWC snapshot button";
+	phys = kasprintf(GFP_KERNEL,"usb-%s-%s", pdev->udev->bus->bus_name, pdev->udev->devpath);
+	if (!phys) {
+		input_free_device(pdev->button_dev);
+		return -ENOMEM;
+	}
+	pdev->button_dev->phys = phys;
+	usb_to_input_id(pdev->udev, &pdev->button_dev->id);
+	pdev->button_dev->dev.parent = &pdev->udev->dev;
+	pdev->button_dev->evbit[0] = BIT_MASK(EV_KEY);
+	pdev->button_dev->keybit[BIT_WORD(BTN_0)] = BIT_MASK(BTN_0);
+
+	rc = input_register_device(pdev->button_dev);
+	if (rc) {
+		input_free_device(pdev->button_dev);
+		kfree(pdev->button_dev->phys);
+		pdev->button_dev = NULL;
+		return rc;
+	}
+#endif
+
 	return 0;
 
 err_unreg:

drivers/media/video/pwc/pwc.h

@@ -37,6 +37,9 @@
 #include <linux/videodev.h>
 #include <media/v4l2-common.h>
 #include <media/v4l2-ioctl.h>
+#ifdef CONFIG_USB_PWC_INPUT_EVDEV
+#include <linux/input.h>
+#endif
 
 #include "pwc-uncompress.h"
 #include <media/pwc-ioctl.h>
@@ -255,6 +258,9 @@ struct pwc_device
    int pan_angle;			/* in degrees * 100 */
    int tilt_angle;			/* absolute angle; 0,0 is home position */
    int snapshot_button_status;		/* set to 1 when the user push the button, reset to 0 when this value is read */
+#ifdef CONFIG_USB_PWC_INPUT_EVDEV
+   struct input_dev *button_dev;	/* webcam snapshot button input */
+#endif
 
    /*** Misc. data ***/
    wait_queue_head_t frameq;		/* When waiting for a frame to finish... */