Hi Mauro, Thanks for continuing the work on this! On Wed, Sep 27, 2017 at 07:23:43PM -0300, Mauro Carvalho Chehab wrote: > Add a glossary of terms for V4L2, as several concepts are complex > enough to cause misunderstandings. > > Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> > --- > Documentation/media/uapi/v4l/glossary.rst | 136 ++++++++++++++++++++++++++++++ > Documentation/media/uapi/v4l/v4l2.rst | 1 + > 2 files changed, 137 insertions(+) > create mode 100644 Documentation/media/uapi/v4l/glossary.rst > > diff --git a/Documentation/media/uapi/v4l/glossary.rst b/Documentation/media/uapi/v4l/glossary.rst > new file mode 100644 > index 000000000000..b6767da1a46e > --- /dev/null > +++ b/Documentation/media/uapi/v4l/glossary.rst > @@ -0,0 +1,136 @@ > +======== > +Glossary > +======== > + > +.. note:: > + > + This goal of section is to standardize the terms used within the V4L2 > + documentation. It is written incrementally as they are standardized in > + the V4L2 documentation. So, it is a Work In Progress. > + > +.. Please keep the glossary entries in alphabetical order > + > +.. glossary:: > + > + Bridge driver > + The same as V4L2 main driver. Not all V4L2 main drivers can be bridge drivers. Mem-to-mem devices, for instance. How about: A driver for a device receiving image data from another device (or transmitting it to a sub-device) controlled by a sub-device driver. Bridge drivers typically act as V4L2 main drivers. > + > + Device Node > + A character device node in the file system used to control and do > + input/output data transfers from/to a Kernel driver. > + > + Digital Signal Processor - DSP > + A specialized microprocessor, with its architecture optimized for > + the operational needs of digital signal processing. > + > + Driver > + The part of the Linux Kernel that implements support > + for a hardware component. > + > + Field-programmable Gate Array - FPGA > + A field-programmable gate array (FPGA) is an integrated circuit > + designed to be configured by a customer or a designer after > + manufacturing. > + > + See https://en.wikipedia.org/wiki/Field-programmable_gate_array. > + > + Hardware component > + A subset of the media hardware. For example an I²C or SPI device, > + or an IP block inside an SoC or FPGA. > + > + Image Signal Processor - ISP > + A specialised processor that implements a set of algorithms for > + processing image data. ISPs may implement algorithms for lens > + shading correction, demosaic, scaling and pixel format conversion > + as well as produce statistics for the use of the control > + algorithms (e.g. automatic exposure, white balance and focus). And perhaps add: ISP drivers often contain a receiver for image data from external source such as a sensor and act as V4L2 main driver. > + > + Inter-Integrated Circuit - I²C > + A multi-master, multi-slave, packet switched, single-ended, > + serial computer bus used to control V4L2 sub-devices. > + > + See http://www.nxp.com/docs/en/user-guide/UM10204.pdf. > + > + Integrated circuit - IC > + A set of electronic circuits on one small flat piece of > + semiconductor material, normally silicon. > + > + Also known as chip. > + > + Intellectual property core - IP core > + In electronic design a semiconductor intellectual property core, > + is a reusable unit of logic, cell, or integrated circuit layout > + design that is the intellectual property of one party. > + IP cores may be licensed to another party or can be owned > + and used by a single party alone. > + > + See https://en.wikipedia.org/wiki/Semiconductor_intellectual_property_core). > + > + IP block > + The same as IP core. > + > + MC-centric > + V4L2 hardware that requires a Media controller. > + > + See :ref:`v4l2_hardware_control`. > + > + Media Controller > + An API designed to expose and control devices and sub-devices > + relationships to applications. > + > + See :ref:`media_controller`. > + > + Media hardware > + A group of hardware components that together make a larger > + user-facing functional media hardware. For instance the SoC ISP IP > + cores and external camera sensors together make a > + camera media hardware. > + > + Media hardware control > + Type of control for a media hardware supported by V4L2 drivers. > + > + See :ref:`v4l2_hardware_control`. > + > + Microprocessor > + An electronic circuitry that carries out the instructions > + of a computer program by performing the basic arithmetic, logical, > + control and input/output (I/O) operations specified by the > + instructions on a single integrated circuit. > + > + SMBus > + A subset of I²C, with defines a stricter usage of the bus. > + > + Serial Peripheral Interface Bus - SPI > + Synchronous serial communication interface specification used for > + short distance communication, primarily in embedded systems. > + > + System on a Chip - SoC > + An integrated circuit that integrates all components of a computer > + or other electronic systems. > + > + V4L2 device node > + A device node that is associated to a V4L2 main driver, > + as specified in :ref:`v4l2_device_naming`. > + > + V4L2 hardware > + A hardware used to on a media device supported by the V4L2 > + subsystem. I'm not sure what this means. Nor I think the proposed term is good for the reasons elaborated earlier. "Media hardware" above has similar issues. What we would need a name for is a device that consists of other devices that are not usable individually, but instead as an ensemble. I think "aggregate device", for instance, would be good as it catches the essence of the nature of the system. We'd have "Media aggregate device" and "V4L2 aggregate device". An alternative would be simply to leave this out for now, but then we'll have issues elsewhere. I'm certainly open for better options if someone can come up with a better name. > + > + V4L2 main driver > + The V4L2 device driver that implements the main logic to talk with > + the V4L2 hardware. > + > + Also known as bridge driver. > + > + See :ref:`v4l2_hardware_control`. > + > + V4L2 sub-device > + Part of the media hardware that is implemented via a > + V4L2 sub-device driver. > + > + See :ref:`subdev`. > + > + Vdevnode-centric I think this looks quite awkward. How about "Video device node centric" or "Video node centric"? I don't think it'd be too long. > + V4L2 hardware that it is controlled via V4L2 device nodes. > + > + See :ref:`v4l2_hardware_control`. > diff --git a/Documentation/media/uapi/v4l/v4l2.rst b/Documentation/media/uapi/v4l/v4l2.rst > index 2128717299b3..698c060939f0 100644 > --- a/Documentation/media/uapi/v4l/v4l2.rst > +++ b/Documentation/media/uapi/v4l/v4l2.rst > @@ -32,6 +32,7 @@ This part describes the Video for Linux API version 2 (V4L2 API) specification. > videodev > capture-example > v4l2grab-example > + glossary > biblio > > -- Regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx
