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[1/2] media: ca docs: document CA_SET_DESCR ioctl and structs

Message ID 25b64639e9b3c7880a64b20955174196c877fdb8.1504526763.git.mchehab@s-opensource.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mauro Carvalho Chehab Sept. 4, 2017, 12:15 p.m. UTC 
The av7110 driver uses CA_SET_DESCR to store the descrambler
control words at the CA descrambler slots.

Document it.

Thanks-to: Honza Petrouš <jpetrous@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
 Documentation/media/uapi/dvb/ca-set-descr.rst | 15 ++-------------
 include/uapi/linux/dvb/ca.h                   |  9 ++++++++-
 2 files changed, 10 insertions(+), 14 deletions(-)
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Patch

diff --git a/Documentation/media/uapi/dvb/ca-set-descr.rst b/Documentation/media/uapi/dvb/ca-set-descr.rst
index 9c484317d55c..a6c47205ffd8 100644
--- a/Documentation/media/uapi/dvb/ca-set-descr.rst
+++ b/Documentation/media/uapi/dvb/ca-set-descr.rst
@@ -28,22 +28,11 @@  Arguments
 ``msg``
   Pointer to struct :c:type:`ca_descr`.
 
-.. c:type:: ca_descr
-
-.. code-block:: c
-
-    struct ca_descr {
-	unsigned int index;
-	unsigned int parity;
-	unsigned char cw[8];
-    };
-
-
 Description
 -----------
 
-.. note:: This ioctl is undocumented. Documentation is welcome.
-
+CA_SET_DESCR is used for feeding descrambler CA slots with descrambling
+keys (refered as control words).
 
 Return Value
 ------------
diff --git a/include/uapi/linux/dvb/ca.h b/include/uapi/linux/dvb/ca.h
index f66ed53f4dc7..a62ddf0cebcd 100644
--- a/include/uapi/linux/dvb/ca.h
+++ b/include/uapi/linux/dvb/ca.h
@@ -109,9 +109,16 @@  struct ca_msg {
 	unsigned char msg[256];
 };
 
+/**
+ * struct ca_descr - CA descrambler control words info
+ *
+ * @index: CA Descrambler slot
+ * @parity: control words parity, where 0 means even and 1 means odd
+ * @cw: CA Descrambler control words
+ */
 struct ca_descr {
 	unsigned int index;
-	unsigned int parity;	/* 0 == even, 1 == odd */
+	unsigned int parity;
 	unsigned char cw[8];
 };