[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>

Documentation/DocBook/media/v4l/compat.xml

@@ -2393,6 +2393,10 @@ details.</para>
 	    to the <link linkend="control">User controls class</link>.
 	  </para>
         </listitem>
+        <listitem>
+	  <para>Added the device_caps field to struct v4l2_capabilities and added the new
+	  V4L2_CAP_DEVICE_CAPS capability.</para>
+        </listitem>
       </orderedlist>
     </section>
 

Documentation/DocBook/media/v4l/v4l2.xml

@@ -127,6 +127,13 @@ structs, ioctls) must be noted in more detail in the history chapter
 (compat.xml), along with the possible impact on existing drivers and
 applications. -->
 
+      <revision>
+	<revnumber>3.3</revnumber>
+	<date>2012-01-11</date>
+	<authorinitials>hv</authorinitials>
+	<revremark>Added device_caps field to struct v4l2_capabilities.</revremark>
+      </revision>
+
       <revision>
 	<revnumber>3.2</revnumber>
 	<date>2011-08-26</date>
@@ -417,7 +424,7 @@ and discussions on the V4L mailing list.</revremark>
 </partinfo>
 
 <title>Video for Linux Two API Specification</title>
- <subtitle>Revision 3.2</subtitle>
+ <subtitle>Revision 3.3</subtitle>
 
   <chapter id="common">
     &sub-common;

Documentation/DocBook/media/v4l/vidioc-querycap.xml

@@ -124,12 +124,35 @@ printf ("Version: %u.%u.%u\n",
 	  <row>
 	    <entry>__u32</entry>
 	    <entry><structfield>capabilities</structfield></entry>
-	    <entry>Device capabilities, see <xref
-		linkend="device-capabilities" />.</entry>
+	    <entry>Available capabilities of the physical device as a whole, see <xref
+		linkend="device-capabilities" />. The same physical device can export
+		multiple devices in /dev (e.g. /dev/videoX, /dev/vbiY and /dev/radioZ).
+		The <structfield>capabilities</structfield> field should contain a union
+		of all capabilities available around the several V4L2 devices exported
+		to userspace.
+		For all those devices the <structfield>capabilities</structfield> field
+		returns the same set of	capabilities. This allows applications to open
+		just one of the devices (typically the video device) and discover whether
+		video, vbi and/or radio are also supported.
+	    </entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>
-	    <entry><structfield>reserved</structfield>[4]</entry>
+	    <entry><structfield>device_caps</structfield></entry>
+	    <entry>Device capabilities of the opened device, see <xref
+		linkend="device-capabilities" />. Should contain the available capabilities
+		of that specific device node. So, for example, <structfield>device_caps</structfield>
+		of a radio device will only contain radio related capabilities and
+		no video or vbi capabilities. This field is only set if the <structfield>capabilities</structfield>
+		field contains the <constant>V4L2_CAP_DEVICE_CAPS</constant> capability.
+		Only the <structfield>capabilities</structfield> field can have the
+		<constant>V4L2_CAP_DEVICE_CAPS</constant> capability, <structfield>device_caps</structfield>
+		will never set <constant>V4L2_CAP_DEVICE_CAPS</constant>.
+	    </entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>reserved</structfield>[3]</entry>
 	    <entry>Reserved for future extensions. Drivers must set
 this array to zero.</entry>
 	  </row>
@@ -276,6 +299,13 @@ linkend="async">asynchronous</link> I/O methods.</entry>
 	    <entry>The device supports the <link
 linkend="mmap">streaming</link> I/O method.</entry>
 	  </row>
+	  <row>
+	    <entry><constant>V4L2_CAP_DEVICE_CAPS</constant></entry>
+	    <entry>0x80000000</entry>
+	    <entry>The driver fills the <structfield>device_caps</structfield>
+	    field. This capability can only appear in the <structfield>capabilities</structfield>
+	    field and never in the <structfield>device_caps</structfield> field.</entry>
+	  </row>
 	</tbody>
       </tgroup>
     </table>

drivers/media/video/cx231xx/cx231xx-417.c

@@ -1686,7 +1686,6 @@ static struct v4l2_capability pvr_capability = {
 	.capabilities   = (V4L2_CAP_VIDEO_CAPTURE |
 			   V4L2_CAP_TUNER | V4L2_CAP_AUDIO | V4L2_CAP_RADIO |
 			 V4L2_CAP_STREAMING | V4L2_CAP_READWRITE),
-	.reserved       = {0, 0, 0, 0}
 };
 static int vidioc_querycap(struct file *file, void  *priv,
 				struct v4l2_capability *cap)

drivers/media/video/pvrusb2/pvrusb2-v4l2.c

@@ -96,7 +96,6 @@ static struct v4l2_capability pvr_capability ={
 	.capabilities   = (V4L2_CAP_VIDEO_CAPTURE |
 			   V4L2_CAP_TUNER | V4L2_CAP_AUDIO | V4L2_CAP_RADIO |
 			   V4L2_CAP_READWRITE),
-	.reserved       = {0,0,0,0}
 };
 
 static struct v4l2_fmtdesc pvr_fmtdesc [] = {

drivers/media/video/v4l2-ioctl.c

@@ -540,10 +540,12 @@ static long __video_do_ioctl(struct file *file,
 		if (!ret)
 			dbgarg(cmd, "driver=%s, card=%s, bus=%s, "
 					"version=0x%08x, "
-					"capabilities=0x%08x\n",
+					"capabilities=0x%08x, "
+					"device_caps=0x%08x\n",
 					cap->driver, cap->card, cap->bus_info,
 					cap->version,
-					cap->capabilities);
+					cap->capabilities,
+					cap->device_caps);
 		break;
 	}
 

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
  */