[media] cec: document the error codes

Document all the various error codes returned by the CEC ioctls.

These were never documented, instead the documentation relied on a reference
to the generic error codes, but that's not sufficient.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/cec/cec-ioc-adap-g-log-addrs.rst

@@ -351,3 +351,16 @@ On success 0 is returned, on error -1 and the ``errno`` variable is set
 appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
 
+The :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>` can return the following
+error codes:
+
+ENOTTY
+    The ``CEC_CAP_LOG_ADDRS`` capability wasn't set, so this ioctl is not supported.
+
+EBUSY
+    The CEC adapter is currently configuring itself, or it is already configured and
+    ``num_log_addrs`` is non-zero, or another filehandle is in exclusive follower or
+    initiator mode, or the filehandle is in mode ``CEC_MODE_NO_INITIATOR``.
+
+EINVAL
+    The contents of struct :c:type:`cec_log_addrs` is invalid.

Documentation/media/uapi/cec/cec-ioc-adap-g-phys-addr.rst

@@ -78,3 +78,16 @@ Return Value
 On success 0 is returned, on error -1 and the ``errno`` variable is set
 appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
+
+The :ref:`ioctl CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` can return the following
+error codes:
+
+ENOTTY
+    The ``CEC_CAP_PHYS_ADDR`` capability wasn't set, so this ioctl is not supported.
+
+EBUSY
+    Another filehandle is in exclusive follower or initiator mode, or the filehandle
+    is in mode ``CEC_MODE_NO_INITIATOR``.
+
+EINVAL
+    The physical address is malformed.

Documentation/media/uapi/cec/cec-ioc-dqevent.rst

@@ -174,3 +174,14 @@ Return Value
 On success 0 is returned, on error -1 and the ``errno`` variable is set
 appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
+
+The :ref:`ioctl CEC_DQEVENT <CEC_DQEVENT>` can return the following
+error codes:
+
+EAGAIN
+    This is returned when the filehandle is in non-blocking mode and there
+    are no pending events.
+
+ERESTARTSYS
+    An interrupt (e.g. Ctrl-C) arrived while in blocking mode waiting for
+    events to arrive.

Documentation/media/uapi/cec/cec-ioc-g-mode.rst

@@ -249,3 +249,15 @@ Return Value
 On success 0 is returned, on error -1 and the ``errno`` variable is set
 appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
+
+The :ref:`ioctl CEC_S_MODE <CEC_S_MODE>` can return the following
+error codes:
+
+EINVAL
+    The requested mode is invalid.
+
+EPERM
+    Monitor mode is requested without having root permissions
+
+EBUSY
+    Someone else is already an exclusive follower or initiator.

Documentation/media/uapi/cec/cec-ioc-receive.rst

@@ -289,3 +289,40 @@ Return Value
 On success 0 is returned, on error -1 and the ``errno`` variable is set
 appropriately. The generic error codes are described at the
 :ref:`Generic Error Codes <gen-errors>` chapter.
+
+The :ref:`ioctl CEC_RECEIVE <CEC_RECEIVE>` can return the following
+error codes:
+
+EAGAIN
+    No messages are in the receive queue, and the filehandle is in non-blocking mode.
+
+ETIMEDOUT
+    The ``timeout`` was reached while waiting for a message.
+
+ERESTARTSYS
+    The wait for a message was interrupted (e.g. by Ctrl-C).
+
+The :ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>` can return the following
+error codes:
+
+ENOTTY
+    The ``CEC_CAP_TRANSMIT`` capability wasn't set, so this ioctl is not supported.
+
+EPERM
+    The CEC adapter is not configured, i.e. :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
+    has never been called.
+
+ENONET
+    The CEC adapter is not configured, i.e. :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
+    was called, but the physical address is invalid so no logical address was claimed.
+
+EBUSY
+    Another filehandle is in exclusive follower or initiator mode, or the filehandle
+    is in mode ``CEC_MODE_NO_INITIATOR``. This is also returned if the transmit
+    queue is full.
+
+EINVAL
+    The contents of struct :c:type:`cec_msg` is invalid.
+
+ERESTARTSYS
+    The wait for a successful transmit was interrupted (e.g. by Ctrl-C).