media: dvb-net.rst: document DVB network kAPI interface

That's the last DVB kAPI that misses documentation.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/kapi/dtv-core.rst

@@ -34,3 +34,4 @@ I2C bus.
     dtv-frontend
     dtv-demux
     dtv-ca
+    dtv-net

Documentation/media/kapi/dtv-net.rst

+Digital TV Network kABI
+-----------------------
+
+.. kernel-doc:: drivers/media/dvb-core/dvb_net.h

Documentation/media/uapi/dvb/net-types.rst

 .. -*- coding: utf-8; mode: rst -*-
 
-.. _dmx_types:
+.. _net_types:
 
 **************
 Net Data Types

drivers/media/dvb-core/dvb_net.h

@@ -30,6 +30,22 @@
 
 #ifdef CONFIG_DVB_NET
 
+/**
+ * struct dvb_net - describes a DVB network interface
+ *
+ * @dvbdev:		pointer to &struct dvb_device.
+ * @device:		array of pointers to &struct net_device.
+ * @state:		array of integers to each net device. A value
+ *			different than zero means that the interface is
+ *			in usage.
+ * @exit:		flag to indicate when the device is being removed.
+ * @demux:		pointer to &struct dmx_demux.
+ * @ioctl_mutex:	protect access to this struct.
+ *
+ * Currently, the core supports up to %DVB_NET_DEVICES_MAX (10) network
+ * devices.
+ */
+
 struct dvb_net {
 	struct dvb_device *dvbdev;
 	struct net_device *device[DVB_NET_DEVICES_MAX];
@@ -39,8 +55,22 @@ struct dvb_net {
 	struct mutex ioctl_mutex;
 };
 
-void dvb_net_release(struct dvb_net *);
-int  dvb_net_init(struct dvb_adapter *, struct dvb_net *, struct dmx_demux *);
+/**
+ * dvb_net_init - nitializes a digital TV network device and registers it.
+ *
+ * @adap:	pointer to &struct dvb_adapter.
+ * @dvbnet:	pointer to &struct dvb_net.
+ * @dmxdemux:	pointer to &struct dmx_demux.
+ */
+int dvb_net_init(struct dvb_adapter *adap, struct dvb_net *dvbnet,
+		  struct dmx_demux *dmxdemux);
+
+/**
+ * dvb_net_release - releases a digital TV network device and unregisters it.
+ *
+ * @dvbnet:	pointer to &struct dvb_net.
+ */
+void dvb_net_release(struct dvb_net *dvbnet);
 
 #else