On 10/10/2017 10:20 AM, Mauro Carvalho Chehab wrote:
> Em Tue, 10 Oct 2017 09:47:13 +0200
> Hans Verkuil <[email protected]> escreveu:
>
>> On 09/28/2017 12:23 AM, 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 <[email protected]>
>>> ---
>>> 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.
>>
>> Change this to the more standard phrase:
>>
>> See: V4L2 main driver.
>>
>>> +
>>> + Device Node
>>> + A character device node in the file system used to control and do
>>
>> and -> and/or
>>
>>> + 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.
>>
>> I'd say 'requirements' instead of 'needs'. I think that's a better term.
>>
>>> +
>>> + 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).
>>> +
>>> + Inter-Integrated Circuit - I²C
>>> + A multi-master, multi-slave, packet switched, single-ended,
>>> + serial computer bus used to control V4L2 sub-devices.
>>
>> I'd rephrase this a bit:
>>
>> A multi-master, multi-slave, packet switched, single-ended,
>> serial computer bus. Most V4L2 sub-devices are controlled via
>> this bus.
>>
>> Your text suggested that i2c is used exclusively for V4L2 subdevs, but
>> of course it is used for many other devices as well.
>>
>>> +
>>> + 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.
>>
>> Perhaps add an entry for 'Chip' as well, with a 'See: Integrated circuit' as
>> description? Just to be consistent.
>>
>>> +
>>> + 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.
>>
>> 'See: '
>>
>>> +
>>> + 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.
>>
>> This sentence is not clear. I propose this:
>>
>> An API designed to expose and control the relationships of the Media
>> Harware 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
>>
>> I'd just say "form the functional". The term 'user-facing' is out of place
>> here.
>>
>>> + cores and external camera sensors together make a
>>
>> make a -> form the
>>
>> Possible synonym for 'form': 'constitute'. I'm OK with either.
>>
>>> + 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.
>>
>> No idea what you mean here. Perhaps this:
>>
>> Hardware that is controlled by a V4L2 main driver or a V4L2 sub-device
>> driver.
>> V4L2 hardware is a subset of the Media hardware. Often the two are the same,
>> but Media hardware can also contain other non-V4L2 hardware such as DVB
>> hardware.
>>
>>> +
>>> + 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.
>>
>> When we talk about 'V4L2 sub-device' we talk about a driver that implement
>> the subdev kernel API. I suggest that you change 'V4L2 sub-device' to
>> 'V4L2 sub-device driver', then explain that such a driver implements support
>> for a Hardware component.
>>
>>> +
>>> + See :ref:`subdev`.
>>> +
>>> + Vdevnode-centric
>>> + V4L2 hardware that it is controlled via V4L2 device nodes.
>>
>> 'that it' -> 'that'
>>
>> This also needs a reference:
>>
>> See :ref:`v4l2_hardware_control`.
>>
>>> +
>>> + 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,
>>
>> Hans
>
> I agree with all proposed changes. I'm folding the attached patch to it.
>
> Thanks,
> Mauro
>
> diff --git a/Documentation/media/uapi/v4l/glossary.rst
> b/Documentation/media/uapi/v4l/glossary.rst
> index b6767da1a46e..e95820d91bac 100644
> --- a/Documentation/media/uapi/v4l/glossary.rst
> +++ b/Documentation/media/uapi/v4l/glossary.rst
> @@ -13,15 +13,18 @@ Glossary
> .. glossary::
>
> Bridge driver
> - The same as V4L2 main driver.
> + See: V4L2 main driver.
> +
> + Chip:
> + See: Integrated circuit.
>
> Device Node
> - A character device node in the file system used to control and do
> - input/output data transfers from/to a Kernel driver.
> + A character device node in the file system used to control and/or
> + 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.
> + the operational requirements of digital signal processing.
>
> Driver
> The part of the Linux Kernel that implements support
> @@ -47,7 +50,8 @@ Glossary
>
> Inter-Integrated Circuit - I²C
> A multi-master, multi-slave, packet switched, single-ended,
> - serial computer bus used to control V4L2 sub-devices.
> + serial computer bus. Most V4L2 sub-device are controlled
> + via this bus.
>
> See http://www.nxp.com/docs/en/user-guide/UM10204.pdf.
>
> @@ -67,7 +71,7 @@ Glossary
> See
> https://en.wikipedia.org/wiki/Semiconductor_intellectual_property_core).
>
> IP block
> - The same as IP core.
> + See: IP core.
>
> MC-centric
> V4L2 hardware that requires a Media controller.
> @@ -75,15 +79,15 @@ Glossary
> See :ref:`v4l2_hardware_control`.
>
> Media Controller
> - An API designed to expose and control devices and sub-devices
> - relationships to applications.
> + An API designed to expose and control the relationships of the Media
> + Harware 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
> + A group of hardware components that together form the
> + functional media hardware. For instance the SoC ISP IP
> + cores and external camera sensors together form the
> camera media hardware.
>
> Media hardware control
> @@ -113,8 +117,10 @@ Glossary
> as specified in :ref:`v4l2_device_naming`.
>
> V4L2 hardware
> - A hardware used to on a media device supported by the V4L2
> - subsystem.
> + Hardware that is controlled by a V4L2 main driver or a V4L2
> + sub-device driver. V4L2 hardware is a subset of the
> + Media hardware. Often the two are the same, but Media hardware
> + can also contain other non-V4L2 hardware such as DVB hardware.
>
> V4L2 main driver
> The V4L2 device driver that implements the main logic to talk with
> @@ -125,12 +131,15 @@ Glossary
> See :ref:`v4l2_hardware_control`.
>
> V4L2 sub-device
> - Part of the media hardware that is implemented via a
> - V4L2 sub-device driver.
> + See: :ref:`V4L2 sub-device driver`
> +
> + V4L2 sub-device driver
> + Part of the media hardware that implements support for
> + a hardware component.
The description now no longer fits the term. I suggest:
"The V4L2 driver that implements support for a hardware component."
Otherwise this looks good.
Regards,
Hans
>
> See :ref:`subdev`.
>
> Vdevnode-centric
> - V4L2 hardware that it is controlled via V4L2 device nodes.
> + V4L2 hardware that is controlled via V4L2 device nodes.
>
> See :ref:`v4l2_hardware_control`.
>
>
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