[media] V4L2: Add per-device-node capabilities

If V4L2_CAP_DEVICE_CAPS is set, then the new device_caps field is filled with
the capabilities of the opened device node.

The capabilities field traditionally contains the capabilities of the physical
device, being a superset of all capabilities available at the several device
nodes. E.g., if you open /dev/video0, then if it contains VBI caps then that means
that there is a corresponding vbi node as well. And the capabilities field of
both the video and vbi nodes should contain identical caps.

However, it would be very useful to also have a capabilities field that contains
just the caps for the currently open device, hence the new CAP bit and field.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 20 insertions, 9 deletions

diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 5e11f8a1f867..0db05033c2ec 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -235,16 +235,25 @@ struct v4l2_fract {
         __u32   denominator;
 };
 
-/*
- *      D R I V E R   C A P A B I L I T I E S
- */
+/**
+  * struct v4l2_capability - Describes V4L2 device caps returned by VIDIOC_QUERYCAP
+  *
+  * @driver:       name of the driver module (e.g. "bttv")
+  * @card:         name of the card (e.g. "Hauppauge WinTV")
+  * @bus_info:     name of the bus (e.g. "PCI:" + pci_name(pci_dev) )
+  * @version:      KERNEL_VERSION
+  * @capabilities: capabilities of the physical device as a whole
+  * @device_caps:  capabilities accessed via this particular device (node)
+  * @reserved:     reserved fields for future extensions
+  */
 struct v4l2_capability {
-        __u8    driver[16];     /* i.e. "bttv" */
-        __u8    card[32];       /* i.e. "Hauppauge WinTV" */
-        __u8    bus_info[32];   /* "PCI:" + pci_name(pci_dev) */
-        __u32   version;        /* should use KERNEL_VERSION() */
-        __u32   capabilities;   /* Device capabilities */
-        __u32   reserved[4];
+        __u8    driver[16];
+        __u8    card[32];
+        __u8    bus_info[32];
+        __u32   version;
+        __u32   capabilities;
+        __u32   device_caps;
+        __u32   reserved[3];
 };
 
 /* Values for 'capabilities' field */
@@ -274,6 +283,8 @@ struct v4l2_capability {
 #define V4L2_CAP_ASYNCIO                0x02000000  /* async I/O */
 #define V4L2_CAP_STREAMING              0x04000000  /* streaming I/O ioctls */
 
+#define V4L2_CAP_DEVICE_CAPS            0x80000000  /* sets device capabilities field */
+
 /*
  *      V I D E O   I M A G E   F O R M A T
  */