On 20 October 2016 18:30:19 BST, Jonathan Cameron <jic23@xxxxxxxxxxxxxxxxxxxxx> wrote: > > >On 20 October 2016 13:55:12 BST, Lars-Peter Clausen <lars@xxxxxxxxxx> >wrote: >>On 10/20/2016 11:25 AM, Peter Rosin wrote: >>> Hi! >>> >>> These two drivers share the fact that they wrap another iio channel, >>> and I use the first in combination with the second, which is why I'm >>> submitting them as a pair. >>> >>> The first driver is a simple wrapper converting an iio dpot into an >>> iio dac. It only changes the unit and scale. It also does not add >any >>> fancy iio buffer support that I don't need. I suppose that can be >>> added. By someone else :-) >>> >>> Please look over the scale conversion, notably for the fractional >>log2 >>> case that I don't need myself, so is untested. Maybe I should just >>> remove it? >>> >>> Also, is there some agreed-upon way to dig out the maximum value >from >>> an iio channel? If so, "dpot-dac,max-ohms" can be eliminated from >the >>> dt bindings, which would have been nice... >> >>Yes, this is something we could really use. In a sense it exists for >>the >>devices with buffer-capable channels where there is the real_bits >field >>which tells us the data width of the channel. But a dedicated >mechanism >>for >>querying the maximum (and minimum) valid code seems like a useful >>feature. >>Not only for in-kernel clients, but also for userspace. >This was something that was addressed by the rather ancient patch >series i posted that added >an available call back which provided info on range and values for all >info mask elements. >Series got buried by there being a lot of precursors but quite a few of >those have merged since. > >Hmm Google won't let me find it on my phone. Was a while back now. Will >try to get on pc with > decent email archive later and dig out a reference. http://marc.info/?l=linux-iio&m=138469765309868&w=2 I think... > >> >>> >>> I'm also wondering if I'm somehow abusing the regulator? I only >added >>> it to get rid of a "dpot-dac,max-voltage" thing from the dt >bindings. >>> It feels right though, but maybe I should do more with it than check >>> its voltage? What? >> >>Enable the regulator when it is in use? >> >>> >>> The second driver (the envelope detector) is more involved. It also >>> explains why I need the dpot-dac driver. I wanted the envelope >>> detector to be generic and work with any dac, but I had a dpot... >>> >>> The envelope detector was previously discussed late last year [1], >>> and this is what I came up with instead of that mess. >>> >>> There are a couple of things to be said about the envelope detector, >>> one question is where it should live? I placed it in the adc >>directory, >>> but maybe it deserves an iio directory of its own? I'm also a bit >>> worried that the name is a wee bit too generic. But what is a good >>> name? I don't want it to be too long like dac-comp-envelope-detector >>> and something like dac-comp-env-det is just unreadable. Naming is >>> difficult... And suggestions? >> >>Yeah, it is a bit tricky. It is a envelope detector built from >discrete >>components, but of course there are many more ways to build one. If >you >>have >>a codename for your platform you could use this for the DT compatible >>string, like 'vendor,foobar-envelope-detector'. >> >>> >>> Another thing is that I'm not 100% satisfied with the fact that you >>> have to decide at instantiation if you are going to invert the >search >>> or not (search from below). But in order for that to be selectable >>> at runtime with a channel attribute of some sort, I need to be able >>> to rebind the interrupt to the other edge and I want to do that >>> without releasing the irq and grabbing it again (someone might >>> otherwise steal the irq, making the driver lose the irq all >>together). >>> I don't see any API to change the irq trigger condition. Is there >>> such a thing? >>> >>> Anyway, despite all the above questions and remarks, this works for >>> me. Please consider applying. >> >>In general this series looks really good, good and clear >implementation >>as >>well as documentation. A few minor bits here and there, but that is >>normal. -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
