Hi Mauro, (CC'ing Kieran) Thank you for the patch. On Tuesday, 25 September 2018 22:14:51 EEST Mauro Carvalho Chehab wrote: > From: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> > > Add a glossary of terms used within the media userspace API > documentation, as several concepts are complex enough to cause > misunderstandings. > > Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx> > --- > > v3: > - Add SPDX header and dual-license the glossary > - Make glossary generic enough to be used for all media uAPI > documentation; - Add a few new items to the glossary, to imply that it > covers not only V4L2; - Move it to the uAPI document as a hole. > > v2: Did some changes based on Sakari's feedback. > > Documentation/media/media_uapi.rst | 3 + > Documentation/media/uapi/glossary.rst | 162 ++++++++++++++++++++++++++ > 2 files changed, 165 insertions(+) > create mode 100644 Documentation/media/uapi/glossary.rst > > diff --git a/Documentation/media/media_uapi.rst > b/Documentation/media/media_uapi.rst index 28eb35a1f965..41f091a26003 > 100644 > --- a/Documentation/media/media_uapi.rst > +++ b/Documentation/media/media_uapi.rst > @@ -2,6 +2,8 @@ > > .. include:: <isonum.txt> > > +.. _media_uapi: > + > ######################################## > Linux Media Infrastructure userspace API > ######################################## > @@ -31,3 +33,4 @@ License". > uapi/cec/cec-api > uapi/gen-errors > uapi/fdl-appendix > + uapi/glossary Is there an easy way to cross-reference to the glossary when terms are used ? > diff --git a/Documentation/media/uapi/glossary.rst > b/Documentation/media/uapi/glossary.rst new file mode 100644 > index 000000000000..9e2a2b29e8b2 > --- /dev/null > +++ b/Documentation/media/uapi/glossary.rst > @@ -0,0 +1,162 @@ > +.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-or-later > + > +.. For GPL-2.0, see LICENSES/preferred/GPL-2.0 > +.. > +.. For GFDL-1.1-or-later, see: > +.. > +.. Permission is granted to copy, distribute and/or modify this document > +.. under the terms of the GNU Free Documentation License, Version 1.1 or > +.. any later version published by the Free Software Foundation, with no > +.. Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. > +.. A copy of the license is included at > +.. Documentation/media/uapi/fdl-appendix.rst. > + > +======== > +Glossary > +======== > + > +.. note:: > + > + This goal of section is to standardize the terms used within the media > + userspace API documentation. It is written incrementally as they are > + standardized in the media documentation. > + > + So, it is a Work In Progress. > + > +.. Please keep the glossary entries in alphabetical order > + > +.. glossary:: > + > + Bridge driver Shouldn't all words start with a capital letter ? > + A device driver that implements the main logic to talk with > + a media hardware. Terms that are part of the glossary should also be capitalized (and cross- referenced within the glossary). Hardware is still uncountable in English. I know we've discussed this previously, but if we want to write a glossary, it should be in English. Maybe we need to involve a native English speaker here. Kieran ? :-) Additionally, I don't think the definition is correct. Bridges, as defined in V4L2, are opposed to subdevs, while "media hardware" in your definition includes everything. This needs to be clarified. > + For V4L2 hardware, this is also known as V4L2 main driver. Do we use the term V4L2 main driver in the V4L2 spec ? > + Consumer Electronics Control API > + An API designed to receive and transmit data via a HDMI > + CEC interface. So the definition of "Consumer Electronics Control" is CEC ? :-) It would be more useful to do it the other way around, define CEC as Consumer Electronics Control, and explain what it is. > + See :ref:`cec`. > + > + Device Node > + A character device node in the file system used to control and do > + input/output data transfers from/to a Kernel driver. Maybe "and transfer data in and out of a kernel driver" ? > + > + Digital TV API - DVB API Is DVB the same as Digital TV ? The digital video API (https://linuxtv.org/ downloads/v4l-dvb-apis-new/uapi/v4l/dv-timings.html) is sometimes referred to digital TV too. How about standardizing on DVB and avoiding digital TV completely in the specification ? > + An API designed to control the media device components related to > + digital TV, including frontends, demuxes, streaming, conditional > + access, etc. > + > + See :ref:`dvbapi`. > + > + Digital Signal Processor - DSP Here and below I would put the abbreviation first. If someone looks up a term in the glossary because they don't know what it means, they're more likely to search for the abbreviation, not the full term. > + A specialized microprocessor, with its architecture optimized for > + the operational needs of digital signal processing. Stupid question, do we need this entry in the glossary ? The term DSP doesn't seem to be used anywhere in the documentation, and in a video context, I expect the definition of ISP to be more relevant. I also wonder whether we shouldn't drop terms that are defined by the industry (such as DSP, FPGA, I2C, IC, IP core, ISP, Microprocessor, SMBus and SPI), and only focus on terms that have a custom definition in the Linux media subsystem. > + Driver > + 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. > + > + Inter-Integrated Circuit - I²C > + A multi-master, multi-slave, packet switched, single-ended, > + serial computer bus used to control some hardware components > + like sub-device hardware components. > + > + 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. > + > + Intelectual property core - IP block > + 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). > + > + 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). > + > + Media API > + A set of userspace APIs used to control a media hardware. How about explcitly listing the APIs that the umbrella term "Media API" covers ? > + See :ref:`media_uapi`. > + > + Media Controller > + An API designed to expose and control devices and sub-devices' > + relationships to applications. What do you mean by "relationships to applications" ? > + See :ref:`media_controller`. > + > + Media Hardware > + Subset of a hardware that is supported by the Linux Media API. > + > + Includes audio and video capture and playback hardware, > + digital and analog TV, camera sensors, ISPs, remote controllers, > + codecs, HDMI Consumer Electronics Control, HDMI capture, etc. > + > + > + See :ref:`media_uapi`. > + > + Extra blank space ? > + 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. > + > + Remote Controller API > + An API designed to receive and transmit data from remote > + controllers. > + > + See :ref:`remote_controllers`. > + > + 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. > + > + Sub-device hardware components > + V4L2 hardware components that aren't controlled by a > + V4L2 main driver. > + > + V4L2 userspace API - V4L2 API > + The userspace API defined at :ref:`v4l2spec`, with is used to s/at/in/ > control > + a V4L2 hardware. > + > + V4L2 hardware > + Part of a media hardware with is supported by the V4L2 > + userspace API. That's kind of a circular definition, isn't it ? > + V4L2 main driver > + A V4L2 device driver that implements the main logic to talk with > + a V4L2 hardware. > + > + V4L2 sub-device > + Part of a media hardware that it is implemented by a device s/it is/is/ > + driver that is not part of the main V4L2 driver. I don't think that's correct a V4L2 subdev is a software object, not a piece of hardware. > + See :ref:`subdev`. -- Regards, Laurent Pinchart
