Messages in this thread | | | Subject | Re: [PATCH 0/4] IIO wrapper drivers, dpot-dac and envelope-detector | From | Peter Rosin <> | Date | Thu, 20 Oct 2016 16:53:45 +0200 |
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On 2016-10-20 14:55, Lars-Peter Clausen wrote: > On 10/20/2016 11:25 AM, Peter Rosin wrote: >> 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.
For the dpot I have, real_bits (if provided) would not be too great since the maximum value is 256 (i.e. 257 possible wiper positions). I doesn't feel like I'm the most qualified person to add these new min/max attributes though, as I'm not familiar with most parts of the iio code. I'll happily jump on board if they are somehow magically available, of course :-)
>> 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?
Right, I didn't express myself all that clearly, I do in fact already enable the regulator in ->probe and disable it in ->remove. Anything else?
>> 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'.
Good idea! Then the "envelope-detector,inverted" bool can go, and be implied by the compatible string. If some way to rebind the irq trigger is later discovered that can be added as a channel attr without deprecating any dt bindings stuff. While at it, the other properties ("envelope-detector,dac-max" and "envelope-detector,comp-interval-ms") could also be implied from the compatible string. Would that be better? I think so.
But, the compatible string is one thing and the driver name is another. "axentia,tse850-envelope-detector" doesn't seem like the best of driver names...
Are there any existing examples of drivers for (generic) things built with discrete components like this that could perhaps provide guidance?
>> 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.
Thanks, appreciated!
Cheers, Peter
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