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| author | Hans Verkuil <hverkuil@xs4all.nl> | 2016-11-09 09:00:53 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-11-16 18:26:13 +0100 |
| commit | e92ca73b7057ebdba5ea926f25f51b77b41f6c80 (patch) | |
| tree | f0e2ea7b1f824f6eb2f98605b2945e16038c3ca0 /Documentation | |
| parent | [media] DaVinci-VPFE-Capture: Replace a memcpy() call by an assignment in vpf... (diff) | |
| download | linux-e92ca73b7057ebdba5ea926f25f51b77b41f6c80.tar.xz linux-e92ca73b7057ebdba5ea926f25f51b77b41f6c80.zip | |
[media] cec-core.rst: improve documentation
Improve the internal CEC documentation. In particular add a section
that specifies that transmit-related interrupts should be processed
before receive interrupts.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/media/kapi/cec-core.rst | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/Documentation/media/kapi/cec-core.rst b/Documentation/media/kapi/cec-core.rst index 88c33b53ec13..8a88dd4ce3d4 100644 --- a/Documentation/media/kapi/cec-core.rst +++ b/Documentation/media/kapi/cec-core.rst @@ -106,13 +106,13 @@ your driver: int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr); int (*adap_transmit)(struct cec_adapter *adap, u8 attempts, u32 signal_free_time, struct cec_msg *msg); - void (\*adap_log_status)(struct cec_adapter *adap); + void (*adap_status)(struct cec_adapter *adap, struct seq_file *file); /* High-level callbacks */ ... }; -The three low-level ops deal with various aspects of controlling the CEC adapter +The five low-level ops deal with various aspects of controlling the CEC adapter hardware: @@ -238,6 +238,18 @@ When a CEC message was received: Speaks for itself. +Implementing the interrupt handler +---------------------------------- + +Typically the CEC hardware provides interrupts that signal when a transmit +finished and whether it was successful or not, and it provides and interrupt +when a CEC message was received. + +The CEC driver should always process the transmit interrupts first before +handling the receive interrupt. The framework expects to see the cec_transmit_done +call before the cec_received_msg call, otherwise it can get confused if the +received message was in reply to the transmitted message. + Implementing the High-Level CEC Adapter --------------------------------------- @@ -247,11 +259,11 @@ CEC protocol driven. The following high-level callbacks are available: .. code-block:: none struct cec_adap_ops { - /\* Low-level callbacks \*/ + /* Low-level callbacks */ ... - /\* High-level CEC message callback \*/ - int (\*received)(struct cec_adapter \*adap, struct cec_msg \*msg); + /* High-level CEC message callback */ + int (*received)(struct cec_adapter *adap, struct cec_msg *msg); }; The received() callback allows the driver to optionally handle a newly @@ -263,7 +275,7 @@ received CEC message If the driver wants to process a CEC message, then it can implement this callback. If it doesn't want to handle this message, then it should return -ENOMSG, otherwise the CEC framework assumes it processed this message and -it will not no anything with it. +it will not do anything with it. CEC framework functions |