media: ca docs: document CA_SET_DESCR ioctl and structs

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>
This commit is contained in:
Mauro Carvalho Chehab 2017-09-03 20:50:17 -04:00
parent 56d51b65bc
commit bd9049edc6
2 changed files with 10 additions and 14 deletions

View File

@ -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
------------

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@ -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];
};