[media] ca-get-slot-info.rst: document struct ca_slot_info

Add documentation for struct ca_slot_info and for the two
sets of define used by it, according with what's there at the
ca.h header.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/dvb/ca-get-slot-info.rst

@@ -26,7 +26,89 @@ Arguments
   File descriptor returned by a previous call to :c:func:`open() <cec-open>`.
 
 ``info``
-  Undocumented.
+  Pointer to struct c:type:`ca_slot_info`.
+
+.. _ca_slot_info_type:
+
+.. flat-table:: ca_slot_info types
+    :header-rows:  1
+    :stub-columns: 0
+
+    -
+      - type
+      - name
+      - description
+    -
+       - CA_CI
+       - 1
+       - CI high level interface
+
+    -
+       - CA_CI_LINK
+       - 2
+       - CI link layer level interface
+
+    -
+       - CA_CI_PHYS
+       - 4
+       - CI physical layer level interface
+
+    -
+       - CA_DESCR
+       - 8
+       - built-in descrambler
+
+    -
+       - CA_SC
+       - 128
+       - simple smart card interface
+
+.. _ca_slot_info_flag:
+
+.. flat-table:: ca_slot_info flags
+    :header-rows:  1
+    :stub-columns: 0
+
+    -
+      - type
+      - name
+      - description
+
+    -
+       - CA_CI_MODULE_PRESENT
+       - 1
+       - module (or card) inserted
+
+    -
+       - CA_CI_MODULE_READY
+       - 2
+       -
+
+.. c:type:: ca_slot_info
+
+.. flat-table:: struct ca_slot_info
+    :header-rows:  1
+    :stub-columns: 0
+
+    -
+      - type
+      - name
+      - description
+
+    -
+       - int
+       - num
+       - slot number
+
+    -
+       - int
+       - type
+       - CA interface this slot supports, as defined at :ref:`ca_slot_info_type`.
+
+    -
+       - unsigned int
+       - flags
+       - flags as defined at :ref:`ca_slot_info_flag`.
 
 
 Description