On 20.10.2016 19:17, Peter Rosin wrote:
On 2016-10-20 19:37, Jonathan Cameron wrote:
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:
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...
Interesting, one issue with that is that it is all in real world
units, while I'd rather have the raw value.
Um.. It's been a while, but the principle was (IIRC) that every
_available would match the units fo the associated info mask element.
Thus if you have a _raw element it would be in adc counts (most likely).
_input would be in relevant real world units, scale etc in the whatever
units the value itself is in.
So, I would need to
convert back to the raw value using the scale, which sounds boring
but doable. However, I wonder if calibration may also be involved
with that conversion back to raw for some channels? That sounds a
bit more driver specific and potentially troublesome...
I've not had a chance to look at your code (only picked up on this as
there was a fair length thread developing), but I wouldn't have thought
we'd
need to deal with calibrations. Might need them to move to real world
units from raw but that's always the case anyway (unfortunately).
Jonathan
Cheers,
Peter
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