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-rw-r--r--Documentation/driver-api/media/tx-rx.rst25
1 files changed, 13 insertions, 12 deletions
diff --git a/Documentation/driver-api/media/tx-rx.rst b/Documentation/driver-api/media/tx-rx.rst
index e1e9258dd8..29d66a47b5 100644
--- a/Documentation/driver-api/media/tx-rx.rst
+++ b/Documentation/driver-api/media/tx-rx.rst
@@ -6,8 +6,8 @@ Pixel data transmitter and receiver drivers
===========================================
V4L2 supports various devices that transmit and receive pixel data. Examples of
-these devices include a camera sensor, a TV tuner and a parallel or a CSI-2
-receiver in an SoC.
+these devices include a camera sensor, a TV tuner and a parallel, a BT.656 or a
+CSI-2 receiver in an SoC.
Bus types
---------
@@ -22,12 +22,13 @@ the host SoC. It is defined by the `MIPI alliance`_.
.. _`MIPI alliance`: https://www.mipi.org/
-Parallel
-^^^^^^^^
+Parallel and BT.656
+^^^^^^^^^^^^^^^^^^^
-`BT.601`_ and `BT.656`_ are the most common parallel busses.
+The parallel and `BT.656`_ buses transport one bit of data on each clock cycle
+per data line. The parallel bus uses synchronisation and other additional
+signals whereas BT.656 embeds synchronisation.
-.. _`BT.601`: https://en.wikipedia.org/wiki/Rec._601
.. _`BT.656`: https://en.wikipedia.org/wiki/ITU-R_BT.656
Transmitter drivers
@@ -90,8 +91,8 @@ where
pixel rate on the camera sensor's pixel array which is indicated by the
:ref:`V4L2_CID_PIXEL_RATE <v4l2-cid-pixel-rate>` control.
-LP-11 and LP-111 modes
-^^^^^^^^^^^^^^^^^^^^^^
+LP-11 and LP-111 states
+^^^^^^^^^^^^^^^^^^^^^^^
As part of transitioning to high speed mode, a CSI-2 transmitter typically
briefly sets the bus to LP-11 or LP-111 state, depending on the PHY. This period
@@ -105,7 +106,7 @@ in software, especially when there is no interrupt telling something is
happening.
One way to address this is to configure the transmitter side explicitly to LP-11
-or LP-111 mode, which requires support from the transmitter hardware. This is
+or LP-111 state, which requires support from the transmitter hardware. This is
not universally available. Many devices return to this state once streaming is
stopped while the state after power-on is LP-00 or LP-000.
@@ -116,11 +117,11 @@ transitioning to streaming state, but not yet start streaming. Similarly, the
to call ``.post_streamoff()`` for each successful call of ``.pre_streamon()``.
In the context of CSI-2, the ``.pre_streamon()`` callback is used to transition
-the transmitter to the LP-11 or LP-111 mode. This also requires powering on the
+the transmitter to the LP-11 or LP-111 state. This also requires powering on the
device, so this should be only done when it is needed.
-Receiver drivers that do not need explicit LP-11 or LP-111 mode setup are waived
-from calling the two callbacks.
+Receiver drivers that do not need explicit LP-11 or LP-111 state setup are
+waived from calling the two callbacks.
Stopping the transmitter
^^^^^^^^^^^^^^^^^^^^^^^^