On Thu, Oct 05, 2017 at 03:39:29PM -0300, Mauro Carvalho Chehab wrote: > Em Thu, 5 Oct 2017 11:21:07 +0300 > Sakari Ailus <sakari.ailus@xxxxxx> escreveu: > > > Hi Mauro, > > > > My apologies for the late reply. > > > > On Tue, Aug 29, 2017 at 10:07:50AM -0300, Mauro Carvalho Chehab wrote: > > > Em Tue, 29 Aug 2017 10:47:48 +0300 > > > Sakari Ailus <sakari.ailus@xxxxxx> escreveu: > > > > > > > Hi Mauro, > > > > > > > > Thanks for the update. A few comments below. > > > > > > > > On Mon, Aug 28, 2017 at 09:53:55AM -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 | 147 ++++++++++++++++++++++++++++++ > > > > > Documentation/media/uapi/v4l/v4l2.rst | 1 + > > > > > 2 files changed, 148 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..0b6ab5adec81 > > > > > --- /dev/null > > > > > +++ b/Documentation/media/uapi/v4l/glossary.rst > > > > > @@ -0,0 +1,147 @@ > > > > > +======== > > > > > +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. > > > > > > > > I'd leave the WiP part out. > > > > > > IMO, it is important to mention it, as the glossary, right now, covers > > > only what's used on the first two sections of the API book. There are > > > a lot more to be covered. > > > > Works for me. > > > > > > > > > > > > > > + > > > > > +.. Please keep the glossary entries in alphabetical order > > > > > + > > > > > +.. glossary:: > > > > > + > > > > > + Bridge driver > > > > > + The same as V4L2 main driver. > > > > > > > > I've understood bridges being essentially a bus receiver + DMA. Most ISPs > > > > contain both but have more than that. How about: > > > > > > > > A driver for a bus (e.g. parallel, CSI-2) receiver and DMA. Bridge drivers > > > > typically act as V4L2 main drivers. > > > > > > No, only on some drivers the bridge driver has DMA. A vast amount of > > > drivers (USB ones) don't implement any DMA inside the driver, as it is > > > up to the USB host driver to implement support for DMA. > > > > > > There are even some USB host drivers that don't always use DMA for I/O > > > transfers, using direct I/O if the message is smaller than a threshold > > > or not multiple of the bus word. This is pretty common on SoC USB host > > > drivers. > > > > > > In any case, for the effect of this spec, and for all discussions we > > > ever had about it, bridge driver == V4L2 main driver. I don't > > > see any reason why to distinguish between them. > > > > I think you should precisely define what a bridge driver means. Generally > > ISP drivers aren't referred to as bridge drivers albeit they, too, function > > as V4L2 main drivers. > > Btw, this is already defined, currently, at v4l2-subdev.h: > > * Sub-devices are devices that are connected somehow to the main bridge > * device. These devices are usually audio/video muxers/encoders/decoders or > * sensors and webcam controllers. > * > * Usually these devices are controlled through an i2c bus, but other busses > * may also be used. > > Please notice that there it says: "main bridge" :-) > > Such definition was added since the beginning of the subdev concept, back in > 2008 and was reviewed by several V4L core developers: A lot has happened since 2008. :-) Anyway, I'll review the latest set. -- Sakari Ailus e-mail: sakari.ailus@xxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
