diff options
Diffstat (limited to 'Documentation/media/kapi')
| -rw-r--r-- | Documentation/media/kapi/csi2.rst | 17 | ||||
| -rw-r--r-- | Documentation/media/kapi/dtv-frontend.rst | 16 | ||||
| -rw-r--r-- | Documentation/media/kapi/v4l2-controls.rst | 9 | ||||
| -rw-r--r-- | Documentation/media/kapi/v4l2-dev.rst | 1 |
4 files changed, 32 insertions, 11 deletions
diff --git a/Documentation/media/kapi/csi2.rst b/Documentation/media/kapi/csi2.rst index a7e75e2eba85..030a5c41ec75 100644 --- a/Documentation/media/kapi/csi2.rst +++ b/Documentation/media/kapi/csi2.rst @@ -49,9 +49,13 @@ where The transmitter drivers must, if possible, configure the CSI-2 transmitter to *LP-11 mode* whenever the transmitter is powered on but -not active. Some transmitters do this automatically but some have to -be explicitly programmed to do so, and some are unable to do so -altogether due to hardware constraints. +not active, and maintain *LP-11 mode* until stream on. Only at stream +on should the transmitter activate the clock on the clock lane and +transition to *HS mode*. + +Some transmitters do this automatically but some have to be explicitly +programmed to do so, and some are unable to do so altogether due to +hardware constraints. Stopping the transmitter ^^^^^^^^^^^^^^^^^^^^^^^^ @@ -72,3 +76,10 @@ the transmitter up by using the :c:type:`v4l2_subdev_core_ops`->s_power() callback. This may take place either indirectly by using :c:func:`v4l2_pipeline_pm_use` or directly. + +Formats +------- + +The media bus pixel codes document parallel formats. Should the pixel data be +transported over a serial bus, the media bus pixel code that describes a +parallel format that transfers a sample on a single clock cycle is used. diff --git a/Documentation/media/kapi/dtv-frontend.rst b/Documentation/media/kapi/dtv-frontend.rst index fbc5517c8d5a..b362109bb131 100644 --- a/Documentation/media/kapi/dtv-frontend.rst +++ b/Documentation/media/kapi/dtv-frontend.rst @@ -15,8 +15,8 @@ The header file for this API is named ``dvb_frontend.h`` and located in Demodulator driver ^^^^^^^^^^^^^^^^^^ -The demodulator driver is responsible to talk with the decoding part of the -hardware. Such driver should implement :c:type:`dvb_frontend_ops`, with +The demodulator driver is responsible for talking with the decoding part of the +hardware. Such driver should implement :c:type:`dvb_frontend_ops`, which tells what type of digital TV standards are supported, and points to a series of functions that allow the DVB core to command the hardware via the code under ``include/media/dvb_frontend.c``. @@ -120,7 +120,7 @@ Satellite TV reception is:: .. |delta| unicode:: U+00394 -The ``include/media/dvb_frontend.c`` has a kernel thread with is +The ``include/media/dvb_frontend.c`` has a kernel thread which is responsible for tuning the device. It supports multiple algorithms to detect a channel, as defined at enum :c:func:`dvbfe_algo`. @@ -220,11 +220,11 @@ Signal strength (:ref:`DTV-STAT-SIGNAL-STRENGTH`) - As the gain is visible through the set of registers that adjust the gain, typically, this statistics is always available [#f3]_. - - Drivers should try to make it available all the times, as this statistics + - Drivers should try to make it available all the times, as these statistics can be used when adjusting an antenna position and to check for troubles at the cabling. - .. [#f3] On a few devices, the gain keeps floating if no carrier. + .. [#f3] On a few devices, the gain keeps floating if there is no carrier. On such devices, strength report should check first if carrier is detected at the tuner (``FE_HAS_CARRIER``, see :c:type:`fe_status`), and otherwise return the lowest possible value. @@ -232,7 +232,7 @@ Signal strength (:ref:`DTV-STAT-SIGNAL-STRENGTH`) Carrier Signal to Noise ratio (:ref:`DTV-STAT-CNR`) - Signal to Noise ratio for the main carrier. - - Signal to Noise measurement depends on the device. On some hardware, is + - Signal to Noise measurement depends on the device. On some hardware, it is available when the main carrier is detected. On those hardware, CNR measurement usually comes from the tuner (e. g. after ``FE_HAS_CARRIER``, see :c:type:`fe_status`). @@ -323,8 +323,8 @@ A typical example of the logic that handle status and statistics is:: .read_status = foo_get_status_and_stats, }; -Statistics collect -^^^^^^^^^^^^^^^^^^ +Statistics collection +^^^^^^^^^^^^^^^^^^^^^ On almost all frontend hardware, the bit and byte counts are stored by the hardware after a certain amount of time or after the total bit/block diff --git a/Documentation/media/kapi/v4l2-controls.rst b/Documentation/media/kapi/v4l2-controls.rst index ebe2a55908be..b20800cae3f2 100644 --- a/Documentation/media/kapi/v4l2-controls.rst +++ b/Documentation/media/kapi/v4l2-controls.rst @@ -140,6 +140,15 @@ Menu controls with a driver specific menu are added by calling const struct v4l2_ctrl_ops *ops, u32 id, s32 max, s32 skip_mask, s32 def, const char * const *qmenu); +Standard compound controls can be added by calling +:c:func:`v4l2_ctrl_new_std_compound`: + +.. code-block:: c + + struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl, + const struct v4l2_ctrl_ops *ops, u32 id, + const union v4l2_ctrl_ptr p_def); + Integer menu controls with a driver specific menu can be added by calling :c:func:`v4l2_ctrl_new_int_menu`: diff --git a/Documentation/media/kapi/v4l2-dev.rst b/Documentation/media/kapi/v4l2-dev.rst index b359f1804bbe..4c5a15c53dbf 100644 --- a/Documentation/media/kapi/v4l2-dev.rst +++ b/Documentation/media/kapi/v4l2-dev.rst @@ -288,6 +288,7 @@ Mask Description 0x08 Log the read and write file operations and the VIDIOC_QBUF and VIDIOC_DQBUF ioctls. 0x10 Log the poll file operation. +0x20 Log error and messages in the control operations. ===== ================================================================ Video device cleanup |
