[media] cec-core.rst: improve documentation

		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:

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

---------------------------------------

.. 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

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