Re: meter ABI: (was Re: [PATCH v2 1/3] staging:iio:meter: Replaces IIO_DEV_ATTR_CH_OFF by IIO_DEVICE_ATTR)

From: Jonathan Cameron
Date: Sun Mar 25 2018 - 12:29:30 EST

On Sat, 24 Mar 2018 15:45:21 -0700
John Syne <john3909@xxxxxxxxx> wrote:

> > On Mar 24, 2018, at 8:02 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >
> > On Mon, 19 Mar 2018 22:57:16 -0700
> > John Syne <john3909@xxxxxxxxx> wrote:
> >
> >> Hi Jonathan,
> >>
> >> Thank you for all your hard work. Your feedback is really helpful. Iâm surprised that no one from Analog Device has offered any suggestions.
> >>
> >
> > Sadly those active in the mainline linux kernel from ADI are focused in
> > other areas currently :(
> Good point. I will reach out to Analog Devices and get a name of someone
> who is knowledgeable in this area. Perhaps Lars-Peters has a suggestion.
Yes, Lars or Michael Hennerich (+CC) are my normal contact points.
I believe this is outside both of their areas, but they may be able to
put you in contact with the right person. If nothing else it would be
good to make someone in ADI aware that people care about linux support for
these parts!

> >> Anyway, please see my comments inline below
> >>
> >> Regards,
> >> John
> >>
> >>
> >>
> >>
> >>
> >>> On Mar 18, 2018, at 5:23 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >>>
> >>> On Sat, 17 Mar 2018 23:11:45 -0700
> >>> John Syne <john3909@xxxxxxxxx> wrote:
> >>>
> >>>> Hi Jonathan,
> >>> Hi John and All,
> >>>
> >>> I'd love to get some additional input on this from anyone interested.
> >>> There are a lot of weird and wonderful derived quantities in an energy
> >>> meter and it seems we need to make some fundamental changes to support
> >>> them - including potentially a userspace breaking change to the event
> >>> code description.
> >>>
> >>>>
> >>>> Here is the complete list of registers for the ADE7878 which I copied from the data sheet. I added a column âIIO Attributeâ which I hope follows your IIO ABI. Please make any changes you feel are incorrect. BTW, there are several registers that cannot be generalized and are used purely for chip configuration. I think we should add a new naming convention, namely {register}_{<chip-register-name>}. Also, I see in the sys_bus_iio doc

No, registers can always be broken up in to real meaningful values if
they are exposed to userspace and userspace has a reason to tweak
them.

We never expose raw registers to userspace except through
debugfs and the clue is in the name - purely for debug.


> >
> >
> >
> >
> >>>> in_accel_x_peak_raw
> >>>>
> >>>> so shouldnât the phase be represented as follows:
> >>>>
> >>>> in_current_A_scale
> >>> I'm still confused. What does A represent here? I assumed that was a wild
> >>> card for the channel number before but clearly not.
> >>>
> >>> Ah, you are labelling the 3 separate phases as A, B and C. Hmm.
> >>> I guess they sort of look like axis, and sort of like independent channels.
> >>> So could be indexed or done via modifiers depending on how you look at it.
> >> In metering terminology, the three phases are commonly referred to as RED, GREEN, BLUE or PhaseA, PhaseB, PhaseC and Neutral. Analog Devices uses the ABCN nomenclature so anyone using this driver will probably have referenced the Analog Devices datasheet so this terminology should be familiar.
> > Which is more commonly used in general? We are designing what we hope
> > will be a general interface and last thing we want is to have everyone
> > not using ADI parts confused! Personally not assigning 'colours' makes
> > more sense to me.
> I did a little research and here is the naming used by vendor:
>
> ST Microelectronics: P1, P2, P3, N
> http://www.st.com/content/ccc/resource/technical/document/application_note/5e/f4/22/4d/90/96/4c/c4/CD00153264.pdf/files/CD00153264.pdf/jcr:content/translations/en.CD00153264.pdf
>
> Teridian: ABCN
> https://www.mouser.com/ds/2/256/71M6513-71M6513H-22603.pdf
>
> Maxim Integrated: ABCN
> https://datasheets.maximintegrated.com/en/ds/78M6631.pdf
>
> Microchip: ABCN
> http://ww1.microchip.com/downloads/en/DeviceDoc/51643b.pdf
>
> NXP: L1, L2, L3, N
> https://www.nxp.com/support/developer-resources/reference-designs/kinetis-km3x-256-mcu-three-phase-metering-reference-design:RD-KM3x-256-3PH-METERING
>
> Renesas: ABCN
> https://www.renesas.com/en-us/solutions/home/metering/power-meter-three.html
>
> So the most consistent would be ABCN
Cool. Makes sense to go with that. Thanks for checking this out.

>
>
> All vendor providing three phase energy metering ICs use the ABCN terminology.
> >
> > (btw please wrap any lines that don't need to be long to around 80 characters).
> >
> >>>
> >>> Hmm. With neutral in there as well I guess we need to make them
> >>> modifiers (but might change my mind later ;)
> >>>
> >>> Particularly as we are using the the modifier for RMS under the previous
> >>> plan... It appears we should treat that instead like we did for peak
> >>> and do it as an additional info mask element. The problem with doing that
> >>> on a continuous measurement is that we can't treat it as a channel to
> >>> be output through the buffered interface.
> >> Iâve changed the layout of the spreadsheet to breakout the Direction, Type, Index, Modifier and Info Mask to make sure there is no miss-understanding and will help identify all the items we need to add.
> >>
> >> The ADE7878 channels that will use the buffer are IAWV, VAWV, IBWV, VBWV, ICWV, VCWV, INWV, AVA, BVA, CVA, AWATT, BWATT, CWATT, AVAR, BVAR, and CVAR. So I guess we have to add an index
> > Probably a good idea anyway, we are sort of slowly moving away
> > from index less channels. The ABI always allowed index assignment
> > and it makes for easier userspace code.
> >
> >>
> >> Address Register IIO Attribute Dir Type Index Modifier Info Mask R/W Bit Bit Length Type Default Description
> >> Length During Comm Value
> >> 0xE50C IAWV in_current0_phaseA_instantaneous in current 0 phaseA instantaneous R 24 32 SE S N/A Instantaneous value of Phase A current.
> >
> > I'm unconvinced by "instantaneous". That is the default assumption that you are
> > measuring current at this point in time. I'm still confused on what this actually
> > is. Is it effectively the DC current? I.e. the wave form value for current?
> > You answer this below. They are DC measurements..
> No, they are the output of the ADC at a point in time. The ADC samples
> continuous at 8,000 samples per second, so when you read this register
> you are getting the sample measured just before your read. I donât know
> why anyone would read this register. The samples are streamed via
> the SPI interface, with IAWV, VAWV, IBWV, VBWV, ICWV, VCWV, INWV,
> AVA, BVA, CVA, AWATT, BWATT, CWATT, AVAR, BVAR, and CVAR transmitted
> every 125uS. Probably better not to expose these registers to user space.
I'm happy not to expose them, but if they are the instantaneous values
they are what I mean by DC values, literally the number you would
see on an oscilloscope if you were to probe them.

>
>
> >
> > Which actually raises a point I'd forgotten. We have an explicit type
> > for altvoltage (defined for DDS devices as the waveform amplitude IIRC).
> > We should be consistent with that if possible.
> >
> > So I think this should be.
> > in_current0_phaseA_raw
> Yeah, that sounds correct, which reminds me of another issue that does not make
> sense. To me, gain is something that is hardware related and is used to magnify
> an input signal or is used to calibrate a measurement. Scale on the other had is
> something that is used to convert a raw measurement into something that is more
> meaningful, such as 0x820000 = 220V. So everywhere we have used scale and gain
> interchangeable is confusing.

Agreed - up to a point. If you have a hardware gain control which for whatever
reason results in a different scaling needing to be applied to go from userspace
value to real world value (sometimes happens with multi range devices) then we
expose it only once - as scale.

We have hardwaregain and calibgain for tweaking the gain to account for cases
where it isn't apparent in the output value (hardware gain - normally used
when we are measuring something about the signal that isn't it's magnitude),
or is compensating for inaccuracies in the circuitry or sensor (calibgain)
>
> > etc
> > A channel can be uniquely identified using index and modifier as as pair (if we add
> > the new field for computation applied that will also allow separate identification).
> > So the later channels can be.
> >
> > in_current0_phaseB_raw etc
> >
> > Indexes can be shared by different types as well. Often done to associate
> > different measurements of the same signal (though the ABI doesn't specify
> > that).
> >
> >> 0xE50D IBWV in_current1_phaseB_instantaneous in current 1 phaseB instantaneous R 24 32 SE S N/A Instantaneous value of Phase B current.
> >> 0xE50E ICWV in_current2_phaseC_instantaneous in current 2 phaseC instantaneous R 24 32 SE S N/A Instantaneous value of Phase C current.
> >> 0xE50F INWV in_current3_phaseN_instantaneous in current 3 neutral instantaneous R 24 32 SE S N/A Instantaneous value of neutral current (ADE7868 and ADE7878 only).
> > in_voltage0_phaseA_raw
> >
> >> 0xE510 VAWV in_voltage4_phaseA_instantaneous in voltage 4 phaseA instantaneous R 24 32 SE S N/A Instantaneous value of Phase A voltage.
> >> 0xE511 VBWV in_voltage5_phaseB_instantaneous in voltage 5 phaseB instantaneous R 24 32 SE S N/A Instantaneous value of Phase B voltage.
> >> 0xE512 VCWV in_voltage6_phaseC_instantaneous in voltage 6 phaseC instantaneous R 24 32 SE S N/A Instantaneous value of Phase C voltage.
> >> 0xE513 AWATT in_power7_phaseA_instantaneous in power 7 phaseA instantaneous R 24 32 SE S N/A Instantaneous value of Phase A total active power.
> >> 0xE514 BWATT in_power8_phaseB_instantaneous in power 8 phaseB instantaneous R 24 32 SE S N/A Instantaneous value of Phase B total active power.
> >> 0xE515 CWATT in_power9_phaseC_instantaneous in power 9 phaseC instantaneous R 24 32 SE S N/A Instantaneous value of Phase C total active power.
> > in_power0_phaseC_raw
> >
> >> 0xE516 AVAR in_powerreactive10_phaseA_instantaneous in powerreactive 10 phaseA instantaneous R 24 32 SE S N/A Instantaneous value of Phase A total reactive power (ADE7858, ADE7868, and ADE7878 only).
> > in_powerreactive0_phaseA_raw etc
> >> 0xE517 BVAR in_powerreactive11_phaseB_instantaneous in powerreactive 11 phaseB instantaneous R 24 32 SE S N/A Instantaneous value of Phase B total reactive power (ADE7858, ADE7868, and ADE7878 only).
> >> 0xE518 CVAR in_powerreactive12_phaseC_instantaneous in powerreactive 12 phaseC instantaneous R 24 32 SE S N/A Instantaneous value of Phase C total reactive power (ADE7858, ADE7868, and ADE7878 only).
> >> 0xE519 AVA in_powerapparent13_phaseA_instantaneous in powerapparent 13 phaseA instantaneous R 24 32 SE S N/A Instantaneous value of Phase A apparent power.
> >> 0xE51A BVA in_powerapparent14_phaseB_instantaneous in powerapparent 14 phaseB instantaneous R 24 32 SE S N/A Instantaneous value of Phase B apparent power.
> >> 0xE51B CVA in_powerappatent15_phaseC_instantaneous in powerapparent 15 phaseC instantaneous R 24 32 SE S N/A Instantaneous value of Phase C apparent power.
> >>
> >> The ADE9000 channels that use the buffer are IA, VA, IB, VB, IC, VC and IN
> >>>
> >>> So again we have run out of space. It's increasingly looking like we need
> >>> room for another field in the events - to cleanly represent computed values.
> >>>
> >>> Hmm. What is the current usage? - it's been a while so I had to go
> >>> look in the header.
> >>>
> >>> 0-15 Channel (lots of channels)
> >>> 31-16 Channel 2 (36 modifiers - lots of channels)
> >>> 47-32 Channel Type (31 used so far - this looks most likely to run out of
> >>> space in the long run so leave this one alone).
> >>> 54-48 Event Direction (4 used)
> >>> 55 Differential (1: channel 2 as differential pair 0: as a modifier)
> >>> 63-56 Event Type (6 used)
> >>>
> >>> So I think we can pinch bit 53 as another flag to indicate we have
> >>> a computed value or possibly bit 63 as event types are few and
> >>> far between as well.
> >>>
> >>> Probably reasonable to assume we never have 16 bits worth
> >>> of channels and computed channels at the same time?
> >>> Hence I think we can steal bits off the top of Channel.
> >>> How many do we need? Not sure unfortunately but feels like
> >>> 8 should be plenty.
> >> When you speak of Channels here, are you referring to measurements that will use the buffer? Even when counting all the IIO attributes, the ADE9000 has 462 registers, and not all of those would be defined as attributes. I think 8 Bits should be more than enough.
> > Not quite. This is all about allowing us to differentiate between
> > the actual channels where a channel is a single measurement that we
> > are interested in.
> > So we care about 256 measurements that are otherwise indistinguishable
> > using combination of index, modifier and our new propose
> > computedvalue bit.
> Got it.
> >
> >>>
> >>> The other element of this is we add a new field to iio_chan_spec
> >>> to contain 'derived_type' or something like that which has
> >>> rms and sum squared etc. Over time we can move some of those
> >>> from the modifiers and free up a few entires there.
> >>> So modifier might be "X and Y and Z" with a derived_type of
> >>> sum_squared to give existing sum_squared_x_y_z but no
> >>> rush on that.
> >>>
> >>> Anyhow so now we have an extra element to play that will result
> >>> in a different channel.
> >>>
> >>> Whilst here we should think about any other mods needed to
> >>> that event structure. It is a little unfortunate that this
> >>> will be a breaking change for any old userspace code playing
> >>> with new drivers but it can't be helped as we didn't have
> >>> reserved values in the original definition (oops).
> >>>
> >>> At somepoint we may need to add the 'shared by derived_value'
> >>> info mask but I think we can ignore that for now (seems
> >>> moderately unlikely to have anything in it!)
> >>>>
> >>>> But for now, I followed your instructions from your reply.
> >>>>
> >>>> After finalizing this one, I will work on the ADE9000, which as way more registers ;-)
> >>>>
> >>>> Once we can agree on the register naming, I will update the ADE7854 driver for Rodrigo, which will go a long way to getting it out of staging.
> >>> I'll edit to fit with new scheme and insert indexes which I think would be
> >>> preferred though optional under the ABI as we only have one of each type/
> >>>>
> >>>> Address Register IIO Attribute R/W Bit Length Bit Length During Communications Type Default Value Description
> >>>> 0x4380 AIGAIN in_current0_phaseA_scale R/W 24 32 ZPSE S 0x000000 Phase A current gain adjust.
> >>> A, B, C, N aren't obvious to the lay reader so I suggest we burn a few characters and stick phase in for ABC and just have neutral for
> >>> the neutral one. Not sure about capitalization or not though.
> >>>
> >>>> 0x4381 AVGAIN in_voltage0_phaseA_scale R/W 24 32 ZPSE S 0x000000 Phase A voltage gain adjust.
> >>>> 0x4382 BIGAIN in_current0_phaseB_scale R/W 24 32 ZPSE S 0x000000 Phase B current gain adjust.
> >>>> 0x4383 BVGAIN in_voltage0_phaseB_scale R/W 24 32 ZPSE S 0x000000 Phase B voltage gain adjust.
> >>>> 0x4384 CIGAIN in_current0_phaseC_scale R/W 24 32 ZPSE S 0x000000 Phase C current gain adjust.
> >>>> 0x4385 CVGAIN in_voltage0_phaseC_scale R/W 24 32 ZPSE S 0x000000 Phase C voltage gain adjust.
> >>>> 0x4386 NIGAIN in_current0_neutral_scale R/W 24 32 ZPSE S 0x000000 Neutral current gain adjust (ADE7868 and ADE7878 only).
> >>>> 0x4387 AIRMSOS in_current0_phaseA_rms_offset R/W 24 32 ZPSE S 0x000000 Phase A current rms offset.
> >>>> 0x4388 AVRMSOS in_voltage0_phaseA_rms_offset R/W 24 32 ZPSE S 0x000000 Phase A voltage rms offset.
> >>>> 0x4389 BIRMSOS in_current0_phaseB_rms_offset R/W 24 32 ZPSE S 0x000000 Phase B current rms offset.
> >>>> 0x438A BVRMSOS in_voltage0_phaseB_rms_offset R/W 24 32 ZPSE S 0x000000 Phase B voltage rms offset.
> >>>> 0x438B CIRMSOS in_current0_phaseC_rms_offset R/W 24 32 ZPSE S 0x000000 Phase C current rms offset.
> >>>> 0x438C CVRMSOS in_voltage0_phaseC_rms_offset R/W 24 32 ZPSE S 0x000000 Phase C voltage rms offset.
> >>>> 0x438D NIRMSOS in_current0_neutral_rms_offset R/W 24 32 ZPSE S 0x000000 Neutral current rms offset (ADE7868 and ADE7878 only).
> >>>> 0x438E AVAGAIN in_powerapparent0_phaseA_scale R/W 24 32 ZPSE S 0x000000 Phase A apparent power gain adjust.
> >>>> 0x438F BVAGAIN in_powerapparent0_phaseB_scale R/W 24 32 ZPSE S 0x000000 Phase B apparent power gain adjust.
> >>>> 0x4390 CVAGAIN in_powerapparent0_phaseC_scale R/W 24 32 ZPSE S 0x000000 Phase C apparent power gain adjust.
> >>>> 0x4391 AWGAIN in_power0_phaseA_scale R/W 24 32 ZPSE S 0x000000 Phase A total active power gain adjust.
> >>>> 0x4392 AWATTOS in_power0_phaseA_offset R/W 24 32 ZPSE S 0x000000 Phase A total active power offset adjust.
> >>>> 0x4393 BWGAIN in_power0_phaseB_scale R/W 24 32 ZPSE S 0x000000 Phase B total active power gain adjust.
> >>>> 0x4394 BWATTOS in_power0_phaseB_offset R/W 24 32 ZPSE S 0x000000 Phase B total active power offset adjust.
> >>>> 0x4395 CWGAIN in_power0_PhaseC_scale R/W 24 32 ZPSE S 0x000000 Phase C total active power gain adjust.
> >>>> 0x4396 CWATTOS in_power0_phaseC_offset R/W 24 32 ZPSE S 0x000000 Phase C total active power offset adjust.
> >>>> 0x4397 AVARGAIN in_powerreactive0_phaseA_scale R/W 24 32 ZPSE S 0x000000 Phase A total reactive power gain adjust (ADE7858, ADE7868, and ADE7878).
> >>>> 0x4398 AVAROS in_powerreactive0_phaseA_offset R/W 24 32 ZPSE S 0x000000 Phase A total reactive power offset adjust (ADE7858, ADE7868, and ADE7878).
> >>>> 0x4399 BVARGAIN in_powerreactive0_phaseB_scale R/W 24 32 ZPSE S 0x000000 Phase B total reactive power gain adjust (ADE7858, ADE7868, and ADE7878).
> >>>> 0x439A BVAROS in_powerreactive0_phaseB_offset R/W 24 32 ZPSE S 0x000000 Phase B total reactive power offset adjust (ADE7858, ADE7868, and ADE7878).
> >>>> 0x439B CVARGAIN in_powerreactive0_phaseC_scale R/W 24 32 ZPSE S 0x000000 Phase C total reactive power gain adjust (ADE7858, ADE7868, and ADE7878).
> >>>> 0x439C CVAROS in_powerreactive0_phaseC_offset R/W 24 32 ZPSE S 0x000000 Phase C total reactive power offset adjust (ADE7858, ADE7868, and ADE7878).
> >>>> 0x439D AFWGAIN in_power0_phaseA_fundamental_scale R/W 24 32 ZPSE S 0x000000 Phase A fundamental active power gain adjust. Location reserved for ADE7854, ADE7858, and ADE7868.
> >>> Hmm. fundamental is the oddity here. I here because it is sort of a derived value
> >>> and sort of a filter applied. Can it be sensible combined with RMS? probably not but
> >>> it can be combined with peak for example (which I'd also ideally move into
> >>> the derived representation.).
> >> Includes only the measurement spectrum at 50Hz or 60Hz and does not include harmonic.
> > I think for that we need to define a different indexed channel and define
> > the filters applied with appropriate values to make it a band pass at these
> > frequencies. We may need to expand the current filter definitions to do this
> > but that is fine if needed.
> >
> >
> >>
> >>>
> >>>> 0x439E AFWATTOS in_power0_phaseA_fundamental_offset R/W 24 32 ZPSE S 0x000000 Phase A fundamental active power offset adjust. Location reserved for ADE7854, ADE7858, and ADE7868.
> >>>> 0x439F BFWGAIN in_power0_phaseB_fundamental_scale R/W 24 32 ZPSE S 0x000000 Phase B fundamental active power gain adjust (ADE7878 only).
> >>>> 0x43A0 BFWATTOS in_power0_phaseB_fundamental_offset R/W 24 32 ZPSE S 0x000000 Phase B fundamental active power offset adjust (ADE7878 only).
> >>>> 0x43A1 CFWGAIN in_power0_phaseC_fundamental_scale R/W 24 32 ZPSE S 0x000000 Phase C fundamental active power gain adjust.
> >>>> 0x43A2 CFWATTOS in_power0_phaseC_fundamental_offset R/W 24 32 ZPSE S 0x000000 Phase C fundamental active power offset adjust (ADE7878 only).
> >>>> 0x43A3 AFVARGAIN in_powerreactive0_phaseA_fundamental_scale R/W 24 32 ZPSE S 0x000000 Phase A fundamental reactive power gain adjust (ADE7878 only).
> >>>> 0x43A4 AFVAROS in_powerreactive0_phaseA_fundamental_offset R/W 24 32 ZPSE S 0x000000 Phase A fundamental reactive power offset adjust (ADE7878 only).
> >>>> 0x43A5 BFVARGAIN in_powerreactive0_phaseB_fundamental_scale R/W 24 32 ZPSE S 0x000000 Phase B fundamental reactive power gain adjust (ADE7878 only).
> >>>> 0x43A6 BFVAROS in_powerreactive0_phaseB_fundamental_offset R/W 24 32 ZPSE S 0x000000 Phase B fundamental reactive power offset adjust (ADE7878 only).
> >>>> 0x43A7 CFVARGAIN in_powerreactive0_phaseC_fundamental_scale R/W 24 32 ZPSE S 0x000000 Phase C fundamental reactive power gain adjust (ADE7878 only).
> >>>> 0x43A8 CFVAROS in_powerreactive0_phaseC_fundamental_offset R/W 24 32 ZPSE S 0x000000 Phase C fundamental reactive power offset adjust (ADE7878 only).
> >>>> 0x43A9 VATHR1 regiister_VATHR1 R/W 24 32 ZP U 0x000000 Most significant 24 bits of VATHR[47:0] threshold used in phase apparent power datapath.
> >>> Do not expose these to userspace. Why would it care?
> >> Brilliant, yes these should be moved the the DeviceTree (DT)
> >
> > Cool
> >
> >>>
> >>>> 0x43AA VATHR0 register_VATHR0 R/W 24 32 ZP U 0x000000 Less significant 24 bits of VATHR[47:0] threshold used in phase apparent power datapath.
> >>>> 0x43AB WTHR1 register_WTHR1 R/W 24 32 ZP U 0x000000 Most significant 24 bits of WTHR[47:0] threshold used in phase total/fundamental active power datapath.
> >>>> 0x43AC WTHR0 register_WTHR0 R/W 24 32 ZP U 0x000000 Less significant 24 bits of WTHR[47:0] threshold used in phase total/fundamental active power datapath.
> >>>> 0x43AD VARTHR1 register_VARTHR1 R/W 24 32 ZP U 0x000000 Most significant 24 bits of VARTHR[47:0] threshold used in phase total/fundamental reactive power datapath (ADE7858, ADE7868, and ADE7878).
> >>>> 0x43AE VARTHR0 register_VARTHR0 R/W 24 32 ZP U 0x000000 Less significant 24 bits of VARTHR[47:0] threshold used in phase total/fundamental reactive power datapath (ADE7858, ADE7868, and ADE7878).
> >>>> 0x43AF Reserved N/A4 N/A4 N/A4 N/A4 0x000000 This memory location should be kept at 0x000000 for proper operation.
> >>>> 0x43B0 VANOLOAD register_VANOLOAD R/W 24 32 ZPSE S 0x0000000 No load threshold in the apparent power datapath.
> >>> This one is kind of an event parameter, but one that controls internal creep prevention.
> >>> This will be a driver specific attr I think for now. We may add it to info_mask
> >>> later if we get lots of meter drivers.
> >>> Something like
> >>> in_power0_no_load_thresh though I haven't really thought about it or looked
> >>> for similar precedence.
> >> Again, this is something that would be set and never changed, so I think this should be moved to DT.
> >
> > Cool.
> >
> >>>
> >>>
> >>>> 0x43B1 APNOLOAD register_APNOLOAD R/W 24 32 ZPSE S 0x0000000 No load threshold in the total/fundamental active power datapath.
> >>> in_activepower0_no_load_thresh
> >> DT
> >>>> 0x43B2 VARNOLOAD register_VARNOLOAD R/W 24 32 ZPSE S 0x0000000 No load threshold in the total/fundamental reactive power datapath. Location reserved for ADE7854.
> >>> in_reactivpower0_no_load_thresh
> >> DT
> >>>
> >>>> 0x43B3 VLEVEL register_VLEVEL R/W 24 32 ZPSE S 0x000000 Register used in the algorithm that computes the fundamental active and reactive powers (ADE7878 only).
> >>> This one looks like a characteristic of the circuit attached. So should be devicetree
> >>> or similar and not exposed to userspace.
> >> DT
> >>>
> >>>> 0x43B5 DICOEFF register_DICOEFF R/W 24 32 ZPSE S 0x0000000 Register used in the digital integrator algorithm. If the integrator is turned on, it must be set at 0xFF8000. In practice, it is transmitted as 0xFFF8000.
> >>> no userspace interface.
> >> DT
> >>>
> >>>> 0x43B6 HPFDIS register_HPFDIS R/W 24 32 ZP U 0x000000 Disables/enables the HPF in the current datapath (see Table 34).
> >>> We have controls for high pass filters, you'll need to map on to them.
> >>> Disable is usually setting 3DB point to 0 IIRC.
> >> DT
> >>>
> >>>> 0x43B8 ISUMLVL register_ISUMLVL R/W 24 32 ZPSE S 0x000000 Threshold used in comparison between the sum of phase currents and the neutral current (ADE7868 and ADE7878 only).
> >>> This is an event threshold so needs to map to the events infrastructure
> >>> as best we can. It's actually a pain to describe so may be device specific ABI.
> >> DT. Iâm not sure why this would be mapped to the events infrastructure? There is no event generated by this register.
> > Control parameter of an event I think?
> > So the event description is separate from that of the channels and has it's
> > own extended ABI to describe this sort of value.
> Do you have an example where a control parameter is used with an event?
> I have not seen this anywhere.

Sure in the abi docs these are easy to find as they have
the type of event in the name.

Taking a few relevant entries...

/sys/.../events/in_accel_thresh_rising_en
/sys/.../events/in_accel_thresh_rising_value
/sys/.../events/in_accel_x_thresh_rising_hysteresis
/sys/.../events/in_accel_x_thresh_rising_period
/sys/.../events/in_accel_thresh_rising_low_pass_filter_3db

Grep for iio_event_spec to find how they are defined. It's pretty
similar to a channel and they are associated with a particular channel.

> >
> >>>
> >>>> 0x43BF ISUM register_ISUM R 28 32 ZP S N/A4 Sum of IAWV, IBWV, and ICWV registers (ADE7868 and ADE7878 only).
> >>> So this would be using a modifier for AandBandC phases (similar to the XandYanZ ones for mems devices and
> >>> a derived value of sum I think So would look something like.
> >>> in_current0_phaseA&phaseB&phaseC_sum and yet another channel
> >>>
> >>>> 0x43C0 AIRMS in_current0_phaseA_rms R 24 32 ZP S N/A4 Phase A current rms value.
> >>>> 0x43C1 AVRMS in_voltage0_phaseA_rms R 24 32 ZP S N/A4 Phase A voltage rms value.
> >>>> 0x43C2 BIRMS in_current0_phaseB_rms R 24 32 ZP S N/A4 Phase B current rms value.
> >>>> 0x43C3 BVRMS in_voltage0_phaseB_rms R 24 32 ZP S N/A4 Phase B voltage rms value.
> >>>> 0x43C4 CIRMS in_current0_phaseC_rms R 24 32 ZP S N/A4 Phase C current rms value.
> >>>> 0x43C5 CVRMS in_voltage0_phaseC_rms R 24 32 ZP S N/A4 Phase C voltage rms value.
> >>>> 0x43C6 NIRMS in_current0_neutral_rms R 24 32 ZP S N/A4 Neutral current rms value (ADE7868 and ADE7878 only).
> >>>> 0xE228 Run register_Run R/W 16 16 U 0x0000 Run register starts and stops the DSP. See the Digital Signal Processor section for more details.
> >>> Not exposed to userspace.
> >> DT
> >>>
> >>>> 0xE400 AWATTHR in_energy0_phaseA_raw R 32 32 S 0x00000000 Phase A total active energy accumulation.
> >>>> 0xE401 BWATTHR in_energy0_phaseB_raw R 32 32 S 0x00000000 Phase B total active energy accumulation.
> >>>> 0xE402 CWATTHR in_energy0_phaseC_raw R 32 32 S 0x00000000 Phase C total active energy accumulation.
> >>>> 0xE403 AFWATTHR in_energy0_phaseA_fundamental_raw R 32 32 S 0x00000000 Phase A fundamental active energy accumulation (ADE7878 only).
> >>>> 0xE404 BFWATTHR in_energy0_phaseB_fundamental_raw R 32 32 S 0x00000000 Phase B fundamental active energy accumulation (ADE7878 only).
> >>>> 0xE405 CFWATTHR in_energy0_phaseC_fundamental_raw R 32 32 S 0x00000000 Phase C fundamental active energy accumulation (ADE7878 only).
> >>>> 0xE406 AVARHR in_energyreactive0_phaseA_raw R 32 32 S 0x00000000 Phase A total reactive energy accumulation (ADE7858, ADE7868, and ADE7878 only).
> >>>> 0xE407 BVARHR in_energyreactive0_phaseB_raw R 32 32 S 0x00000000 Phase B total reactive energy accumulation (ADE7858, ADE7868, and ADE7878 only).
> >>>> 0xE408 CVARHR in_energyreactive0_phaseC_raw R 32 32 S 0x00000000 Phase C total reactive energy accumulation (ADE7858, ADE7868, and ADE7878 only).
> >>>> 0xE409 AFVARHR in_energyreactive0_phaseA_fundamental_raw R 32 32 S 0x00000000 Phase A fundamental reactive energy accumulation (ADE7878 only).
> >>>> 0xE40A BFVARHR in_energyreactive0_phaseB_fundamental_raw R 32 32 S 0x00000000 Phase B fundamental reactive energy accumulation (ADE7878 only).
> >>>> 0xE40B CFVARHR in_energyreactive0_phaseC_fundamental_raw R 32 32 S 0x00000000 Phase C fundamental reactive energy accumulation (ADE7878 only).
> >>>> 0xE40C AVAHR in_energyapparent0_phaseA_raw R 32 32 S 0x00000000 Phase A apparent energy accumulation.
> >>>> 0xE40D BVAHR in_energyapparent0_phaseB_raw R 32 32 S 0x00000000 Phase B apparent energy accumulation.
> >>>> 0xE40E CVAHR in_energyapparent0_phaseC_raw R 32 32 S 0x00000000 Phase C apparent energy accumulation.
> >>>> 0xE500 IPEAK in_current0_peak R 32 32 U N/A Current peak register. See Figure 50 and Table 35 for details about its composition.
> >>> Oh goody. I have no idea how we expose the which phase element of this
> >>> cleanly. One option I suppose is to have in_current0_phaseA_peak etc
> >>> and have all but the current peak return an error when read? It is a bit
> >>> nasty but only so much we can do and keep with a consistent interface.
> >>>
> >>>> 0xE501 VPEAK in_voltage_peak R 32 32 U N/A Voltage peak register. See Figure 50 and Table 36 for details about its composition.
> >>> Same as peak.
> >>>
> >>>> 0xE502 STATUS0 register_STATUS0 R/W 32 32 U N/A Interrupt Status Register 0. See Table 37.
> >>>> 0xE503 STATUS1 register_STATUS1 R/W 32 32 U N/A Interrupt Status Register 1. See Table 38.
> >>> No userspace interface except via events interface or error reports.
> >> Isnât this tied to the event framework? My thinking is the user interface should be notified when certain conditions occur.
> >
> > Probably depending on the condition. If it looks like a threshold on something
> > it can go through as an event. If it is a 'fault' detection in the measurement
> > hardware we need to look at a RAS type notification. This is always a tricky
> > topic and the upshot is we normally just end up dumping them in the kernel log
> > as anything else is hard to do (from a persuading other people of it's importance
> > point of view).
> Letâs take some examples:
> STATUS0:0 AEHF Bit set when the Watt hour registers reach threshold.
> This means the Watt hour registers must be read or the watt hour register will
> wrap and you will loose the energy accumulated. So Iâm not sure how IIO handles
> events with user space, but can I assume it is using a poll or select to monitor for
> events?

Do we get interrupts to indicate a state change in here? We can poll otherwise
but it's not exactly elegant to do so. Had a quick look - as this is the
interrupt status register we are fine :)

This would be controlled by something like.
in_power0_thresh_rising_value

>From a userspace point of view, there is an ioctl that gets you an anonymous
chardev. Once you have that you can use poll / select to monitor for events
and act on them.

There is example code in the iio_event_monitor program in toos/iio in the
kernel tree.


>
> STATUS0:6 REVAPA ACCMODE has changed sign. Power is exported rather
> than imported. User space application would use this to indicate the direction
> of power flow.
This is where we start to run into a problem - mostly IIO only allows for
a single threshold for rising and falling on a given channel. No way to
tell which one triggered in the ABI - even code says what and on what channel
it doesn't distinguish multiple levels.

We can play games with defining additional channels but it isn't that elegant.
Now assuming we want to do both directions of change..

in_power0_thresh_either_value = 0
(to indicate a transition across 0 power - I assume the other direction is
negative?)
and associated event code.

>
> STATUS1:0 NLOAD At least one phase has entered no load condition. User
> space app would probably alert the user of a faulty condition.
Not sure what this maps to - but would be based on how it was detected.
Is this effectively 0 current?

>
> STATUS1:3 ZXTOVA Indicates Phase A voltage zero crossing is missing. This
> is another fault condition.

Similar to the rate of change detection in some ways, but only explicitly looks
at the 0 point. We would need something new to represent this I think...

>
> STATUS1:16 SAG This indicates a sag occurred on one of the phases. User
> space appmight signal the user and record this condition to a log file.
This is effectively a measurement of our AC voltage dropping? Simple threshold
event on the phase voltage I think.
>
> STATUS1:17 OV This indicates that an over voltage event occurred and a
> user space app would signal the user and record this to a log file.
Voltage threshold.

>
> All of these conditions can be masked via the MASK0 and MASK1 registers.
>
> Not sure how IIO would handle this?
Masking is handled via the relevant *_en attributes for the events.

>
> >
> >
> >>>
> >>>> 0xE504 AIMAV in_currentA_mav R 20 32 ZP U N/A Phase A current mean absolute value computed during PSM0 and PSM1 modes (ADE7868 and ADE7878 only).
> >>> Probably a longer name as mav is cryptic.
> >>> in_current0_phaseA_meanabs_raw - it could have a scale and all sorts of fun.
> >>> So I think this needs to be using the new derived infrastructure proposed here
> >>> rather than being an info_mask element.
> >> The same way a knowledgeable person understands what RMS means, so they should also understand what MAV means.
> > hehe. I know RMS and not MAV so I suspect it a bit dependent on where exactly you came across
> > the terms ;)
> MAV is just another way to calculate RMS, but is not as accurate. It is just a statistical term,
> Mean Absolute Value (MAV).
Sure.

> >
> >>>
> >>>> 0xE505 BIMAV in_currentB_mav R 20 32 ZP U N/A Phase B current mean absolute value computed during PSM0 and PSM1 modes (ADE7868 and ADE7878 only).
> >>>> 0xE506 CIMAV in_currentC_mav R 20 32 ZP U N/A Phase C current mean absolute value computed during PSM0 and PSM1 modes (ADE7868 and ADE7878 only).
> >>>> 0xE507 OILVL register_OILVL R/W 24 32 ZP U 0xFFFFFF Overcurrent threshold.
> >>>> 0xE508 OVLVL register_OVLVL R/W 24 32 ZP U 0xFFFFFF Overvoltage threshold.
> >>> These presumably result in interrupts? (I'm running out of time so not checking)
> >>> In which case standard event interface should work.
> >>>
> >>>> 0xE509 SAGLVL register_SAGLVL R/W 24 32 ZP U 0x000000 Voltage SAG level threshold.
> >>> That's another event I thinkâ
> >> Again, this is only setting the threshold, not generating any event.
> >
> > What does the threshold result it? Presumably an event so this is exposed as a
> > control parameter of the event. There is a whole set of ABI for thatâ
> Where can I read about this. Are there any good implementations to help me understand?
In a simple case see something like adc/max1363.c

There are more complex cases - just grep iio_event_spec.

> >
> >
> >>>
> >>>> 0xE50A MASK0 register_MASK0 R/W 32 32 U 0x00000000 Interrupt Enable Register 0. See Table 39.
> >>>> 0xE50B MASK1 register_MASK1 R/W 32 32 U 0x00000000 Interrupt Enable Register 1. See Table 40.
> >>>
> >>>> 0xE50C IAWV in_currentA_instantaneous R 24 32 SE S N/A Instantaneous value of Phase A current.
> >>>> 0xE50D IBWV in_currentB_instantaneous R 24 32 SE S N/A Instantaneous value of Phase B current.
> >>>> 0xE50E ICWV in_currentC_instantaneous R 24 32 SE S N/A Instantaneous value of Phase C current.
> >>>> 0xE50F INWV in_currentN_instantaneous R 24 32 SE S N/A Instantaneous value of neutral current (ADE7868 and ADE7878 only).
> >>>> 0xE510 VAWV in_voltageA_instantaneous R 24 32 SE S N/A Instantaneous value of Phase A voltage.
> >>>> 0xE511 VBWV in_voltageB_instantaneous R 24 32 SE S N/A Instantaneous value of Phase B voltage.
> >>>> 0xE512 VCWV in_voltageC_instantaneous R 24 32 SE S N/A Instantaneous value of Phase C voltage.
> >>> OK, this is getting silly. I presume this means the values above are filtered and these
> >>> aren't? If so you need to have channels for both and different filter values.
> >> These are the actual samples from the ADC and not a calculated measurement over 10/12 cycles. These are the samples that are placed in the buffer.
> > OK, so DC values which answers my question above.
> > So this is the 'normal' measurement. For the multi cycle ones we need to
> > represent them as additional measurements using the index and describe the
> > filtering applied to them (or use altvoltage etc to say we are looking
> > at measurements related to the fact they are alternating rather than DC.
> I answered this above. I think we should remove these registers as I cannot see how anyone would use
> them
Cool. Even easier. Though if we have a device that will allow us to push these
through the buffered interface (rather than the SPI master stuff on here)
then we would have the channels, but not export the _RAW attribute - thus
making them readable only as a stream of data.

> >
> >>>
> >>>> 0xE513 AWATT in_powerA_instantaneous R 24 32 SE S N/A Instantaneous value of Phase A total active power.
> >>>> 0xE514 BWATT in_powerB_instantaneous R 24 32 SE S N/A Instantaneous value of Phase B total active power.
> >>>> 0xE515 CWATT in_powerC_instantaneous R 24 32 SE S N/A Instantaneous value of Phase C total active power.
> >>>> 0xE516 AVAR in_powerreactiveA_instantaneous R 24 32 SE S N/A Instantaneous value of Phase A total reactive power (ADE7858, ADE7868, and ADE7878 only).
> >>>> 0xE517 BVAR in_powerreactiveB_instantaneous R 24 32 SE S N/A Instantaneous value of Phase B total reactive power (ADE7858, ADE7868, and ADE7878 only).
> >>>> 0xE518 CVAR in_powerreactiveC_instantaneous R 24 32 SE S N/A Instantaneous value of Phase C total reactive power (ADE7858, ADE7868, and ADE7878 only).
> >>>> 0xE519 AVA in_powerapparentA_instantaneous R 24 32 SE S N/A Instantaneous value of Phase A apparent power.
> >>>> 0xE51A BVA in_powerapparentB_instantaneous R 24 32 SE S N/A Instantaneous value of Phase B apparent power.
> >>>> 0xE51B CVA in_powerappatentC_instantaneous R 24 32 SE S N/A Instantaneous value of Phase C apparent power.
> >>> Same for all of these.
> >>>
> >>>> 0xE51F CHECKSUM register_CHECKSUM R 32 32 U 0x33666787 Checksum verification. See the Checksum Register section for details.
> >>> Not exposed to userspace.
> >> Yeah, this is only used to check the communication for errors.
> >>>
> >>>> 0xE520 VNOM in_voltage_rms_nominal R/W 24 32 ZP S 0x000000 Nominal phase voltage rms used in the alternative computation of the apparent power. When the VNOMxEN bit is set, the applied voltage input in the corresponding phase is ignored and all corresponding rms voltage instances are replaced by the value in the VNOM register.
> >>> Why would this be done? Sounds like something that is a circuit design time
> >>> decision so a job for DT to me.
> >> Yeah, I agree.
> >>>
> >>>> 0xE600 PHSTATUS in_current_phase_peak R 16 16 U N/A Phase peak register. See Table 41.
> >>>> 0xE601 ANGLE0 register_ANGLE0 R 16 16 U N/A Time Delay 0. See the Time Interval Between Phases section for details.
> >>>> 0xE602 ANGLE1 register_ANGLE1 R 16 16 U N/A Time Delay 1. See the Time Interval Between Phases section for details.
> >>>> 0xE603 ANGLE2 register_ANGLE2 R 16 16 U N/A Time Delay 2. See the Time Interval Between Phases section for details.
> >>> Hmm. More fun. These are derived values between to phase measurements.
> >>> The phase as a modifier falls down a bit here - if we had just treated
> >>> them as channels we could have done this a differential angle channel.
> >>> Right now I'm not sure how we do this, could do it as a derived values so something like
> >>> in_angle0_phaseA&phaseB_diff_raw etc but that feels odd.
> >>> This one needs more thought.
> >>>
> >>>> 0xE604 to 0xE606 Reserved These addresses should not be written for proper operation.
> >>>> 0xE607 PERIOD register_PERIOD R 16 16 U N/A Network line period.
> >>> Superficially this sounds like a channel free element so shared_by_all.
> >>>
> >>>> 0xE608 PHNOLOAD register_PHNOLOAD R 16 16 U N/A Phase no load register. See Table 42.
> >>> Hmm. So this is kind of a set of events with but without I think an interrupt.
> >>> Odd.
> >>>
> >>>> 0xE60C LINECYC register_LINECYC R/W 16 16 U 0xFFFF Line cycle accumulation mode count.
> >>> in_count0_raw probably though it's a bit of a stretch.
> >>>
> >>>> 0xE60D ZXTOUT register_ZXTOUT R/W 16 16 U 0xFFFF Zero-crossing timeout count.
> >>> This is going to be another top level one I think and device specific for now.
> >>>
> >>>> 0xE60E COMPMODE register_COMPMODE R/W 16 16 U 0x01FF Computation-mode register. See Table 43.
> >>> If there is stuff to control in here it need breaking out.
> >>>
> >>>> 0xE60F Gain register_Gain R/W 16 16 U 0x0000 PGA gains at ADC inputs. See Table 44.
> >>> Oh goody another scale value. Needs breaking up into separate controls.
> >>> Do these directly effect the measured output voltage etc? If they do then
> >>> I'm not sure how to separate the two gains, there ought to be a 'right'
> >>> answer. If this is about matching to the circuit present then they
> >>> should probably be coming from DT or simillar.
> >>>
> >>>
> >>>> 0xE610 CFMODE register_CFMODE R/W 16 16 U 0x0E88 CFx configuration register. See Table 45.
> >>>> 0xE611 CF1DEN register_CF1DEN R/W 16 16 U 0x0000 CF1 denominator.
> >>>> 0xE612 CF2DEN register_CF2DEN R/W 16 16 U 0x0000 CF2 denominator.
> >>>> 0xE613 CF3DEN register_CF3DEN R/W 16 16 U 0x0000 CF3 denominator.
> >>> Are these things that should be in DT? Look very quickly like they are todo with other circuits nearby.
> >> Agreed
> >>>
> >>>> 0xE614 APHCAL register_APHCAL R/W 10 16 ZP S 0x0000 Phase calibration of Phase A. See Table 46.
> >>>> 0xE615 BPHCAL register_BPHCAL R/W 10 16 ZP S 0x0000 Phase calibration of Phase B. See Table 46.
> >>>> 0xE616 CPHCAL register__CPHCAL R/W 10 16 ZP S 0x0000 Phase calibration of Phase C. See Table 46.
> >>> I'm not actually sure how you would set these. Per circuit design?
> >> There should be some base calibration stored in DT and fine tuned calibration stored in an INI file or custom eeprom of nvram.
> > Hmm. Then we need to expose them to userspace to allow that INI to be applied.
> >
> > Lets deal with the rest first and come back to these. May well need
> > some device specific ABI which is always annoying..
> Agreed
> >
> >>>
> >>>> 0xE617 PHSIGN register_PHSIGN R 16 16 U N/A Power sign register. See Table 47.
> >>>> 0xE618 CONFIG register_CONFIG R/W 16 16 U 0x0000 ADE7878 configuration register. See Table 48.
> >>>> 0xE700 MMODE register__MMODE R/W 8 8 U 0x1C Measurement mode register. See Table 49.
> >>>> 0xE701 ACCMODE register__ACCMODE R/W 8 8 U 0x00 Accumulation mode register. See Table 50.
> >>>> 0xE702 LCYCMODE register_LCYCMODE R/W 8 8 U 0x78 Line accumulation mode behavior. See Table 52.
> >> All to DT
> >>>> 0xE703 PEAKCYC register_PEAKCYC R/W 8 8 U 0x00 Peak detection half line cycles.
> >>>> 0xE704 SAGCYC register_SAGCYC R/W 8 8 U 0x00 SAG detection half line cycles.
> >>> Some of these are event controls. Map them as such.
> >> Agreed
> >>>
> >>>> 0xE705 CFCYC register_CFCYC R/W 8 8 U 0x01 Number of CF pulses between two consecutive energy latches. See the Synchronizing Energy Registers with CFx Outputs section.
> >>>> 0xE706 HSDC_CFG register_HSDC_CFG R/W 8 8 U 0x00 HSDC configuration register. See Table 53.
> >> DT
> >>>> 0xE707 Version register_Version R 8 8 U Version of die.
> >> Might want to expose this to User Space as there could be differences between die version
> >> in_version0_raw
> >>>> 0xEBFF Reserved 8 8 This address can be used in manipulating the SS/HSA pin when SPI is chosen as the active port. See the Serial Interfaces section for details.
> >>>> 0xEC00 LPOILVL register_LPOILVL R/W 8 8 U 0x07 "Overcurrent threshold used during PSM2 mode (ADE7868 and ADE7878
> >>>> only). See Table 54 in which the register is detailed."
> >>>> 0xEC01 CONFIG2 register_CONFIG2 R/W 8 8 U 0x00 Configuration register used during PSM1 mode. See Table 55.
> >> All to DT
> >>>
> >>> As you can guess I was running out of stamina towards the end of that.
> >>>
> >>> I'm not totally sure of the answer I provided. It may take some more thought.
> >>> Ideally some others will give input on this question.
> >>
> >> Thank you again for all your feedback. Iâll generate a new list and send it next.
> > Cool.
> >
> > Jonathan
> >
> >>
> >> Regards,
> >> John
> >>>
> >>> Jonathan
> >>>>
> >>>> Regards,
> >>>> John
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>> On Mar 17, 2018, at 1:30 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >>>>>
> >>>>> On Wed, 14 Mar 2018 23:12:02 -0700
> >>>>> John Syne <john3909@xxxxxxxxx> wrote:
> >>>>>
> >>>>>> Hi Jonathan,
> >>>>>>
> >>>>>> I have been looking at the IIO ABI docs and if I understand
> >>>>>> correctly, the idea is to use consistent naming conventions? So for
> >>>>>> example, looking at the ADE7854 datasheet, the naming matching the
> >>>>>> ADE7854 registers would be as follows:
> >>>>>
> >>>>> Welcome to one of the big reasons no one tidied these drivers
> >>>>> up originally. Still we have moved on somewhat since then
> >>>>> so similar circumstances have come up in other types of sensor.
> >>>>>
> >>>>>>
> >>>>>> {direction}_{type}_{index}_{modifier}_{info_mask}
> >>>>>>
> >>>>>> AIGAIN - In_current_a_gain
> >>>>> Other than the fact that gain isn't an ABI element and that index
> >>>>> doesn't have
> >>>>> _ before it that is right.
> >>>>> in_voltageA_scale
> >>>>>
> >>>>> That was a weird quirk a long time back which we should probably
> >>>>> not have done (copied it from hwmon)
> >>>>>
> >>>>>> AVGAIN - in_voltage_a_gain
> >>>>>> BIGAIN - in_current_b_gain
> >>>>>> BVGAIN - in_voltage_b_gain
> >>>>>> â
> >>>>>> How do we represent the rms and offset
> >>>>>> AIRMSOS - in_current_a_rmsoffset
> >>>>>> AVRMSOS - in_voltage_a_rmsoffset
> >>>>>
> >>>>> Right now we can't unfortunately though this one is easier to fix.
> >>>>> We already have modifiers for multi axis devices doing sum_squared
> >>>>> so add one of those for root_mean_square - this one is well known
> >>>>> enough that rms is fine in the string.
> >>>>>
> >>>>> It's a effectively a different channel be it one derived from a simple
> >>>>> one. This is going to get tricky however as we would normally use
> >>>>> modifier to specialise a channel type - thoughts on this below.
> >>>>>
> >>>>>> â
> >>>>>> Here I donât understand how to represent both the phase and the active/reactive/apparent power components. Do we combine the phase and quadrature part like this
> >>>>>> AVAGAIN - in_power_a_gain /* apparent power */
> >>>>>> â
> >>>>>> AWGAIN - in_power_ai_gain /* active power */
> >>>>> And that is the problem. How do we represent the various power types.
> >>>>> Hmm. We could do it with modifiers but above we show that we have already used them.
> >>>>>
> >>>>> It would be easy enough to add yet another field to the channel spec to specify
> >>>>> this but there is a problem - Events. The event format is already pretty full
> >>>>> so where do we put this extra element if we need to define a channel separated
> >>>>> only by it.
> >>>>>
> >>>>> One thought is we could instead define these as different top level
> >>>>> IIO_CHAN_TYPES in a similar fashion to we do for relative humidity vs
> >>>>> the proposed absolute humidity.
> >>>>>
> >>>>> in_powerreactiveA_scale
> >>>>> in_poweractivceA_scale
> >>>>> (or in_powerrealA_scale to match with what I got taught years ago?)
> >>>>>
> >>>>> I presume we keep in_powerA_scale etc for the apparent power and
> >>>>> modify any docs to make that clear.
> >>>>>
> >>>>>> â
> >>>>>> AVARGAIN - in_power_aq_gain /* reactive power */
> >>>>>> â
> >>>>>> Now here it becomes more complicated. Not sure how this gets handled.
> >>>>>> AFWATTOS - in_power_a_active/fundamental/offset
> >>>>> Yeah, some of these are getting odd.
> >>>>> If I read this correctly this is the active power estimate based on only
> >>>>> the fundamental frequency - so no harmonics?
> >>>>>
> >>>>> Hmm. This then becomes a separate channel with additional properties
> >>>>> specifying it is only the fundamental. This feels a bit like a filter
> >>>>> be it an unusual one? Might just be necessary to add a _fundamental_only
> >>>>> element on the end (would be info_mask if this is common enough to
> >>>>> justify that rather than using the extended methods to define it.).
> >>>>>
> >>>>>
> >>>>>> â
> >>>>>> AWATTHR - in_energy_ai_accumulation
> >>>>> Great, just when I thought we had gone far enough they define reactive
> >>>>> energy which is presumably roughly the same as reactivepower * time?
> >>>>> In that case we need types for that as well.
> >>>>> in_energyreactiveA_*
> >>>>> in_energyactiveA_*
> >>>>>
> >>>>>> â
> >>>>>> AVARHR - in_energy_aq_accumulation
> >>>>>> â
> >>>>>> IPEAK - in_current_peak
> >>>>> That one is easy as we have an info_mask element for peak and one
> >>>>> for peak_scale that has always been a bit odd but was needed somewhere.
> >>>>>
> >>>>>> â
> >>>>>>
> >>>>>> Iâll leave it there, because there are some even more complicated register naming issues.
> >>>>> Something to look forward to. Gah, I always hated power engineering
> >>>>> though I taught it very briefly (I really pity those students :(
> >>>>>
> >>>>> Jonathan
> >>>>>
> >>>>>>
> >>>>>> Regards,
> >>>>>> John
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> On Mar 10, 2018, at 7:10 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >>>>>>>
> >>>>>>> On Thu, 8 Mar 2018 21:37:33 -0300
> >>>>>>> Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx> wrote:
> >>>>>>>
> >>>>>>>> On 03/07, Jonathan Cameron wrote:
> >>>>>>>>> On Tue, 6 Mar 2018 21:43:47 -0300
> >>>>>>>>> Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx> wrote:
> >>>>>>>>>
> >>>>>>>>>> The macro IIO_DEV_ATTR_CH_OFF is a wrapper for IIO_DEVICE_ATTR, with a
> >>>>>>>>>> tiny change in the name definition. This extra macro does not improve
> >>>>>>>>>> the readability and also creates some checkpatch errors.
> >>>>>>>>>>
> >>>>>>>>>> This patch fixes the checkpatch.pl errors:
> >>>>>>>>>>
> >>>>>>>>>> staging/iio/meter/ade7753.c:391: ERROR: Use 4 digit octal (0777) not
> >>>>>>>>>> decimal permissions
> >>>>>>>>>> staging/iio/meter/ade7753.c:395: ERROR: Use 4 digit octal (0777) not
> >>>>>>>>>> decimal permissions
> >>>>>>>>>> staging/iio/meter/ade7759.c:331: ERROR: Use 4 digit octal (0777) not
> >>>>>>>>>> decimal permissions
> >>>>>>>>>> staging/iio/meter/ade7759.c:335: ERROR: Use 4 digit octal (0777) not
> >>>>>>>>>> decimal permissions
> >>>>>>>>>>
> >>>>>>>>>> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx>
> >>>>>>>>>
> >>>>>>>>> Hmm. I wondered a bit about this one. It's a correct patch in of
> >>>>>>>>> itself but the interface in question doesn't even vaguely conform
> >>>>>>>>> to any of defined IIO ABI. Anyhow, it's still and improvement so
> >>>>>>>>> I'll take it.
> >>>>>>>>
> >>>>>>>> I am not sure if I understood the comment about the ABI. The meter
> >>>>>>>> interface is wrong because it uses things like IIO_DEVICE_ATTR? It
> >>>>>>>> should use iio_info together with *write_raw and *read_raw. Right? Is it
> >>>>>>>> the ABI problem that you refer?
> >>>>>>> The ABI is about the userspace interface of IIO. It is defined
> >>>>>>> in Documentation/ABI/testing/sysfs-bus-iio*
> >>>>>>> So this documents the naming of sysfs attributes and (more or less)
> >>>>>>> describes a consistent interface to userspace across lots of different
> >>>>>>> types of devices.
> >>>>>>>
> >>>>>>> A lot of these older drivers in staging involve a good deal of ABI that
> >>>>>>> was not reviewed or discussed. That is one of the biggest reasons we
> >>>>>>> didn't take them out of staging in the first place.
> >>>>>>>
> >>>>>>> In order for generic userspace programs to have any idea what to do
> >>>>>>> with these devices this all needs to be fixed.
> >>>>>>>
> >>>>>>> There may well be cases where we need to expand the existing ABI to
> >>>>>>> cover new things. That's fine, but it has to be done with full
> >>>>>>> review of the relevant documentation patches.
> >>>>>>>
> >>>>>>> Incidentally if you want an easy driver to work on moving out of staging
> >>>>>>> then first thing to do is to compare what it shows to userspace with these
> >>>>>>> docs. If it's totally different then you have a big job on your hands
> >>>>>>> as often ABI can take a lot of discussion and a long time to establish
> >>>>>>> a consensus.
> >>>>>>>
> >>>>>>> Jonathan
> >>>>>>>
> >>>>>>>
> >>>>>>>>
> >>>>>>>> Thanks :)
> >>>>>>>>
> >>>>>>>>> Applied to the togreg branch of iio.git and pushed out as testing
> >>>>>>>>> for the autobuilders to play with it.
> >>>>>>>>>
> >>>>>>>>> I also added the removal of the header define which is no
> >>>>>>>>> longer used.
> >>>>>>>>>
> >>>>>>>>> Please note, following discussions with Michael, I am going to send
> >>>>>>>>> an email announcing an intent to drop these meter drivers next
> >>>>>>>>> cycle unless someone can provide testing for any attempt to
> >>>>>>>>> move them out of staging. I'm still taking patches on the basis
> >>>>>>>>> that 'might' happen - but I wouldn't focus on these until we
> >>>>>>>>> have some certainty on whether they will be around long term!
> >>>>>>>>>
> >>>>>>>>> Jonathan
> >>>>>>>>>
> >>>>>>>>>> ---
> >>>>>>>>>> drivers/staging/iio/meter/ade7753.c | 18 ++++++++++--------
> >>>>>>>>>> drivers/staging/iio/meter/ade7759.c | 18 ++++++++++--------
> >>>>>>>>>> 2 files changed, 20 insertions(+), 16 deletions(-)
> >>>>>>>>>>
> >>>>>>>>>> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
> >>>>>>>>>> index c44eb577dc35..275e8dfff836 100644
> >>>>>>>>>> --- a/drivers/staging/iio/meter/ade7753.c
> >>>>>>>>>> +++ b/drivers/staging/iio/meter/ade7753.c
> >>>>>>>>>> @@ -388,14 +388,16 @@ static IIO_DEV_ATTR_VPERIOD(0444,
> >>>>>>>>>> ade7753_read_16bit,
> >>>>>>>>>> NULL,
> >>>>>>>>>> ADE7753_PERIOD);
> >>>>>>>>>> -static IIO_DEV_ATTR_CH_OFF(1, 0644,
> >>>>>>>>>> - ade7753_read_8bit,
> >>>>>>>>>> - ade7753_write_8bit,
> >>>>>>>>>> - ADE7753_CH1OS);
> >>>>>>>>>> -static IIO_DEV_ATTR_CH_OFF(2, 0644,
> >>>>>>>>>> - ade7753_read_8bit,
> >>>>>>>>>> - ade7753_write_8bit,
> >>>>>>>>>> - ADE7753_CH2OS);
> >>>>>>>>>> +
> >>>>>>>>>> +static IIO_DEVICE_ATTR(choff_1, 0644,
> >>>>>>>>>> + ade7753_read_8bit,
> >>>>>>>>>> + ade7753_write_8bit,
> >>>>>>>>>> + ADE7753_CH1OS);
> >>>>>>>>>> +
> >>>>>>>>>> +static IIO_DEVICE_ATTR(choff_2, 0644,
> >>>>>>>>>> + ade7753_read_8bit,
> >>>>>>>>>> + ade7753_write_8bit,
> >>>>>>>>>> + ADE7753_CH2OS);
> >>>>>>>>>>
> >>>>>>>>>> static int ade7753_set_irq(struct device *dev, bool enable)
> >>>>>>>>>> {
> >>>>>>>>>> diff --git a/drivers/staging/iio/meter/ade7759.c b/drivers/staging/iio/meter/ade7759.c
> >>>>>>>>>> index 1decb2b8afab..c078b770fa53 100644
> >>>>>>>>>> --- a/drivers/staging/iio/meter/ade7759.c
> >>>>>>>>>> +++ b/drivers/staging/iio/meter/ade7759.c
> >>>>>>>>>> @@ -328,14 +328,16 @@ static IIO_DEV_ATTR_ACTIVE_POWER_GAIN(0644,
> >>>>>>>>>> ade7759_read_16bit,
> >>>>>>>>>> ade7759_write_16bit,
> >>>>>>>>>> ADE7759_APGAIN);
> >>>>>>>>>> -static IIO_DEV_ATTR_CH_OFF(1, 0644,
> >>>>>>>>>> - ade7759_read_8bit,
> >>>>>>>>>> - ade7759_write_8bit,
> >>>>>>>>>> - ADE7759_CH1OS);
> >>>>>>>>>> -static IIO_DEV_ATTR_CH_OFF(2, 0644,
> >>>>>>>>>> - ade7759_read_8bit,
> >>>>>>>>>> - ade7759_write_8bit,
> >>>>>>>>>> - ADE7759_CH2OS);
> >>>>>>>>>> +
> >>>>>>>>>> +static IIO_DEVICE_ATTR(choff_1, 0644,
> >>>>>>>>>> + ade7759_read_8bit,
> >>>>>>>>>> + ade7759_write_8bit,
> >>>>>>>>>> + ADE7759_CH1OS);
> >>>>>>>>>> +
> >>>>>>>>>> +static IIO_DEVICE_ATTR(choff_2, 0644,
> >>>>>>>>>> + ade7759_read_8bit,
> >>>>>>>>>> + ade7759_write_8bit,
> >>>>>>>>>> + ADE7759_CH2OS);
> >>>>>>>>>>
> >>>>>>>>>> static int ade7759_set_irq(struct device *dev, bool enable)
> >>>>>>>>>> {
> >>>>>>>>>
> >>>>>>>> --
> >>>>>>>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> >>>>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx
> >>>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
> >>>>>>>
> >>>>>>> _______________________________________________
> >>>>>>> devel mailing list
> >>>>>>> devel@xxxxxxxxxxxxxxxxxxxxxx
> >>>>>>> http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
>