Hi Pavel, On Mon, Feb 13, 2017 at 10:54:20AM +0100, Pavel Machek wrote: > Hi! > > > > Take a look at the wikipedia. If you do "one at a time" at 100Hz, you > > > can claim it is time-domain multiplex. But we are plain switching the > > > cameras. It takes second (or so) to setup the pipeline. > > > > > > This is not multiplex. > > > > The functionality is still the same, isn't it? Does it change what it is if > > the frequency might be 100 Hz or 0,01 Hz? > > Well. In your living your you can have a switch, which is switch at > much less than 0.01Hz. You can also have a dimmer, which is a PWM, > which is switch at 100Hz or so. So yes, I'd say switch and mux are > different things. Light switches are mostly on/off switches. It'd be interesting to have a light switch that you could use to light either of the light bulbs in a room but not to switch both of them on at the same time. Or off... :-) I wonder if everyone would be happy with a statement saying that it's a on / on switch which is used to implement a multiplexer? > > > I was a bit annoyed for having to have two drivers for switching the source > > (one for GPIO, another for syscon / register), where both of the drivers > > would be essentially the same with the minor exception of having a slightly > > different means to toggle the mux setting. > > Well, most of the video-bus-switch is the video4linux glue. Actual > switching is very very small part. So.. where is the other driver? > Looks like we have the same problem. It's here, slightly hidden in plain sight in the same patch with the MUX framework: <URL:https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1328763.html> > > > The MUX framework adds an API for controlling the MUX. Thus we'll need only > > a single driver that uses the MUX framework API for V4L2. As an added bonus, > > V4L2 would be in line with the rest of the MUX usage in the kernel. > > > > The set appears to already contain a GPIO MUX. What's needed would be to use > > the MUX API instead of direct GPIOs usage. > > If there's a driver that already does switching for video4linux > devices? Do you have a pointer? I don't think there's one. But with MUX API, we'll be fine using a single driver instead of two (other one for syscon on iMX). Cc Steve and Philipp. -- Kind regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
