From: "Cercueil, Paul" <Paul.Cercueil@analog.com>
To: "preid@electromag.com.au" <preid@electromag.com.au>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>
Subject: Re: Question on shared attributes
Date: Tue, 28 Jun 2016 10:38:09 +0000 [thread overview]
Message-ID: <1467110288.2364.11.camel@analog.com> (raw)
In-Reply-To: <e87b35bc-36e9-dc1a-a87e-4e1c20db8d2e@electromag.com.au>
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Hi Phil,
I think right now libiio doesn't handle shared-by-dir attributes yet,
only shared-by-type. Ideally, 'in_sampling_frequency' should appear as
a 'sampling_frequency' attribute on all input channels of your module0
device.
Regards,
Paul Cercueil
Le mardi 28 juin 2016 à 16:55 +0800, Phil Reid a écrit :
> G'day All,
>
> Found something interesting.
> For a new iio driver I have a shared attribute on direction.
>
> .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ)
>
> Which results in sysfs attribute name of:
> in_sampling_frequency
>
> Which results in iio_info giving the following output:
> iio:device3: module0
> 7 channels found:
> voltage0: (input)
> 6 channel-specific attributes found:
> attr 0: scale value: 0.000149011
> attr 1: raw value: 0
> attr 2: hardwaregain value: 1
> attr 3: index value: 0
> attr 4: en value: 0
> attr 5: type value: le:s24/32>>0
> voltage1: (input)
> 6 channel-specific attributes found:
> attr 0: raw value: 0
> attr 1: scale value: 0.000149011
> attr 2: hardwaregain value: 1
> attr 3: en value: 0
> attr 4: index value: 1
> attr 5: type value: le:s24/32>>0
> voltage2: (input)
> 6 channel-specific attributes found:
> attr 0: raw value: 0
> attr 1: scale value: 0.000149011
> attr 2: hardwaregain value: 1
> attr 3: en value: 0
> attr 4: index value: 2
> attr 5: type value: le:s24/32>>0
> voltage3: (input)
> 6 channel-specific attributes found:
> attr 0: hardwaregain value: 1
> attr 1: raw value: 0
> attr 2: scale value: 0.000149011
> attr 3: en value: 0
> attr 4: type value: le:s24/32>>0
> attr 5: index value: 3
> voltage4: (output)
> 2 channel-specific attributes found:
> attr 0: raw value: 32768
> attr 1: scale value: 2500000.000000000
> voltage5: (output)
> 2 channel-specific attributes found:
> attr 0: raw value: 32768
> attr 1: scale value: 2500000.000000000
> sampling: (input)
> 1 channel-specific attributes found:
> attr 0: frequency value: 24000
> 2 device-specific attributes found:
> attr 0: freq value: 6144000
> attr 1: out_en value: 0
>
>
> Note that the sampling_frequency attr has been converted into an
> input channel.
>
> Modify the definition in industrialio-core.c
> [IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
> to
> [IIO_CHAN_INFO_SAMP_FREQ] = "samplingfrequency",
>
> Results in the following output:
> iio:device4: module0
> 6 channels found:
> voltage0: (input)
> 6 channel-specific attributes found:
> attr 0: scale value: 0.000149011
> attr 1: raw value: 0
> attr 2: hardwaregain value: 1
> attr 3: index value: 0
> attr 4: en value: 0
> attr 5: type value: le:s24/32>>0
> voltage1: (input)
> 6 channel-specific attributes found:
> attr 0: raw value: 0
> attr 1: scale value: 0.000149011
> attr 2: hardwaregain value: 1
> attr 3: en value: 0
> attr 4: index value: 1
> attr 5: type value: le:s24/32>>0
> voltage2: (input)
> 6 channel-specific attributes found:
> attr 0: raw value: 0
> attr 1: scale value: 0.000149011
> attr 2: hardwaregain value: 1
> attr 3: en value: 0
> attr 4: index value: 2
> attr 5: type value: le:s24/32>>0
> voltage3: (input)
> 6 channel-specific attributes found:
> attr 0: hardwaregain value: 1
> attr 1: raw value: 0
> attr 2: scale value: 0.000149011
> attr 3: en value: 0
> attr 4: type value: le:s24/32>>0
> attr 5: index value: 3
> voltage4: (output)
> 2 channel-specific attributes found:
> attr 0: raw value: 32768
> attr 1: scale value: 2500000.000000000
> voltage5: (output)
> 2 channel-specific attributes found:
> attr 0: raw value: 32768
> attr 1: scale value: 2500000.000000000
> 3 device-specific attributes found:
> attr 0: freq value: 6144000
> attr 1: in_samplingfrequency value: 24000
> attr 2: out_en value: 0
>
> Which makes more sense. So libiio is treating the name sampling as a
> channel name
> in 'in_sampling_frequency' assuming that attributes never have an
> underscore in there name.
>
> I'm guessing the same would be the case for out attributes as well.
>
> A quick search of the drivers in the kernel to date indicate that
> IIO_CHAN_INFO_SAMP_FREQ is generally
> shared by type or all. shared by dir occurs with the
> iio_simple_dummy, but can't see anything with a real device.
> I'm using libiio from git://github.com/analogdevicesinc/libiio.git
>
> So is this intended, or does libiio need to be smarter on identifying
> channels and shared attributes?
> I'm guessing we cant change the kernel interface, which would be the
> easiest fix. :/
>
>
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next prev parent reply other threads:[~2016-06-28 11:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 8:55 Question on shared attributes Phil Reid
2016-06-28 10:38 ` Cercueil, Paul [this message]
2016-06-29 3:24 ` Phil Reid
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