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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