diff mbox series

[v1,02/15] Documentation: ABI: add wideband filter type to sysfs-bus-iio

Message ID 40707fa904ba7b1659554747ff7520139dd6f94e.1736201898.git.Jonathan.Santos@analog.com (mailing list archive)
State Changes Requested
Headers show
Series iio: adc: ad7768-1: Add features, improvements, and fixes | expand

Commit Message

Jonathan Santos Jan. 7, 2025, 3:24 p.m. UTC
The Wideband Low Ripple FIR filter is used for AD7768-1 Driver.
Document wideband filter option into filter_type_avaialable
attribute.

Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
---
 Documentation/ABI/testing/sysfs-bus-iio | 2 ++
 1 file changed, 2 insertions(+)

Comments

David Lechner Jan. 7, 2025, 11:38 p.m. UTC | #1
On 1/7/25 9:24 AM, Jonathan Santos wrote:
> The Wideband Low Ripple FIR filter is used for AD7768-1 Driver.
> Document wideband filter option into filter_type_avaialable

s/avaialable/available/

> attribute.
> 
> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> index f83bd6829285..c4c21a7bfba1 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -2291,6 +2291,8 @@ Description:
>  		* "sinc3+pf2" - Sinc3 + device specific Post Filter 2.
>  		* "sinc3+pf3" - Sinc3 + device specific Post Filter 3.
>  		* "sinc3+pf4" - Sinc3 + device specific Post Filter 4.
> +		* "wideband" - FIR filter with wideband low ripple passband

I think "fir" would be a more specific filter type name than "wideband". (i.e.
there are wikipedia pages for sinc and FIR filters, but not one for "wideband"
filters)

> +		  and sharp transition band.
>  
>  What:		/sys/.../events/in_proximity_thresh_either_runningperiod
>  KernelVersion:	6.6
Jonathan Santos Jan. 11, 2025, 10:50 p.m. UTC | #2
On 01/07, David Lechner wrote:
> On 1/7/25 9:24 AM, Jonathan Santos wrote:
> > The Wideband Low Ripple FIR filter is used for AD7768-1 Driver.
> > Document wideband filter option into filter_type_avaialable
> 
> s/avaialable/available/
> 
> > attribute.
> > 
> > Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-iio | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > index f83bd6829285..c4c21a7bfba1 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > @@ -2291,6 +2291,8 @@ Description:
> >  		* "sinc3+pf2" - Sinc3 + device specific Post Filter 2.
> >  		* "sinc3+pf3" - Sinc3 + device specific Post Filter 3.
> >  		* "sinc3+pf4" - Sinc3 + device specific Post Filter 4.
> > +		* "wideband" - FIR filter with wideband low ripple passband
> 
> I think "fir" would be a more specific filter type name than "wideband". (i.e.
> there are wikipedia pages for sinc and FIR filters, but not one for "wideband"
> filters)
> 

Isn't "fir" a bit too generic for this case? Since Wideband here is a class of a FIR filter.
Maybe something like "wideband-fir" or "fir-wideband" would work better?

> > +		  and sharp transition band.
> >  
> >  What:		/sys/.../events/in_proximity_thresh_either_runningperiod
> >  KernelVersion:	6.6
>
Jonathan Cameron Jan. 12, 2025, 12:16 p.m. UTC | #3
On Sat, 11 Jan 2025 19:50:18 -0300
Jonathan Santos <jonath4nns@gmail.com> wrote:

> On 01/07, David Lechner wrote:
> > On 1/7/25 9:24 AM, Jonathan Santos wrote:  
> > > The Wideband Low Ripple FIR filter is used for AD7768-1 Driver.
> > > Document wideband filter option into filter_type_avaialable  
> > 
> > s/avaialable/available/
> >   
> > > attribute.
> > > 
> > > Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> > > ---
> > >  Documentation/ABI/testing/sysfs-bus-iio | 2 ++
> > >  1 file changed, 2 insertions(+)
> > > 
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > > index f83bd6829285..c4c21a7bfba1 100644
> > > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > > @@ -2291,6 +2291,8 @@ Description:
> > >  		* "sinc3+pf2" - Sinc3 + device specific Post Filter 2.
> > >  		* "sinc3+pf3" - Sinc3 + device specific Post Filter 3.
> > >  		* "sinc3+pf4" - Sinc3 + device specific Post Filter 4.
> > > +		* "wideband" - FIR filter with wideband low ripple passband  
> > 
> > I think "fir" would be a more specific filter type name than "wideband". (i.e.
> > there are wikipedia pages for sinc and FIR filters, but not one for "wideband"
> > filters)
> >   
> 
> Isn't "fir" a bit too generic for this case? Since Wideband here is a class of a FIR filter.
> Maybe something like "wideband-fir" or "fir-wideband" would work better?


Not sure FIR is even useful. That's just a particular filter architecture, not
related directly to the characteristics userspace cares about.
You can sometimes at least build a very similar response from an IIR filter.
The sinc ones describe the pattern they let through, FIR isn't that specific.
So I'd not mention FIR anywhere.

> 
> > > +		  and sharp transition band.
> > >  
> > >  What:		/sys/.../events/in_proximity_thresh_either_runningperiod
> > >  KernelVersion:	6.6  
> >
David Lechner Jan. 12, 2025, 5:39 p.m. UTC | #4
On 1/11/25 4:50 PM, Jonathan Santos wrote:
> On 01/07, David Lechner wrote:
>> On 1/7/25 9:24 AM, Jonathan Santos wrote:
>>> The Wideband Low Ripple FIR filter is used for AD7768-1 Driver.
>>> Document wideband filter option into filter_type_avaialable
>>
>> s/avaialable/available/
>>
>>> attribute.
>>>
>>> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
>>> ---
>>>  Documentation/ABI/testing/sysfs-bus-iio | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
>>> index f83bd6829285..c4c21a7bfba1 100644
>>> --- a/Documentation/ABI/testing/sysfs-bus-iio
>>> +++ b/Documentation/ABI/testing/sysfs-bus-iio
>>> @@ -2291,6 +2291,8 @@ Description:
>>>  		* "sinc3+pf2" - Sinc3 + device specific Post Filter 2.
>>>  		* "sinc3+pf3" - Sinc3 + device specific Post Filter 3.
>>>  		* "sinc3+pf4" - Sinc3 + device specific Post Filter 4.
>>> +		* "wideband" - FIR filter with wideband low ripple passband
>>
>> I think "fir" would be a more specific filter type name than "wideband". (i.e.
>> there are wikipedia pages for sinc and FIR filters, but not one for "wideband"
>> filters)
>>
> 
> Isn't "fir" a bit too generic for this case? Since Wideband here is a class of a FIR filter.
> Maybe something like "wideband-fir" or "fir-wideband" would work better?

For this particular chip, no, there is only one FIR filter option on the chip,
so having additional qualifiers doesn't really make a difference.

If we can find a chip that has more than one FIR filter option, then we could
use that to figure out what additional classifiers are might make sense.
"fir-wideband" would only be useful if the same chip also had a "fir-narrowband"
option. But we might find that instead the chip is actually "fir-type1"
"fir-type2" or something like that.

(FWIW, my signal processing textbook describes Type I, II, III, IV FIR filters
but doesn't say anything about "wideband" FIR filters.)

> 
>>> +		  and sharp transition band.
>>>  
>>>  What:		/sys/.../events/in_proximity_thresh_either_runningperiod
>>>  KernelVersion:	6.6
>>
David Lechner Jan. 12, 2025, 5:41 p.m. UTC | #5
On 1/12/25 11:39 AM, David Lechner wrote:
> On 1/11/25 4:50 PM, Jonathan Santos wrote:
>> On 01/07, David Lechner wrote:
>>> On 1/7/25 9:24 AM, Jonathan Santos wrote:
>>>> The Wideband Low Ripple FIR filter is used for AD7768-1 Driver.
>>>> Document wideband filter option into filter_type_avaialable
>>>
>>> s/avaialable/available/
>>>
>>>> attribute.
>>>>
>>>> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
>>>> ---
>>>>  Documentation/ABI/testing/sysfs-bus-iio | 2 ++
>>>>  1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
>>>> index f83bd6829285..c4c21a7bfba1 100644
>>>> --- a/Documentation/ABI/testing/sysfs-bus-iio
>>>> +++ b/Documentation/ABI/testing/sysfs-bus-iio
>>>> @@ -2291,6 +2291,8 @@ Description:
>>>>  		* "sinc3+pf2" - Sinc3 + device specific Post Filter 2.
>>>>  		* "sinc3+pf3" - Sinc3 + device specific Post Filter 3.
>>>>  		* "sinc3+pf4" - Sinc3 + device specific Post Filter 4.
>>>> +		* "wideband" - FIR filter with wideband low ripple passband
>>>
>>> I think "fir" would be a more specific filter type name than "wideband". (i.e.
>>> there are wikipedia pages for sinc and FIR filters, but not one for "wideband"
>>> filters)
>>>
>>
>> Isn't "fir" a bit too generic for this case? Since Wideband here is a class of a FIR filter.
>> Maybe something like "wideband-fir" or "fir-wideband" would work better?
> 
> For this particular chip, no, there is only one FIR filter option on the chip,
> so having additional qualifiers doesn't really make a difference.
> 
> If we can find a chip that has more than one FIR filter option, then we could
> use that to figure out what additional classifiers are might make sense.
> "fir-wideband" would only be useful if the same chip also had a "fir-narrowband"
> option. But we might find that instead the chip is actually "fir-type1"
> "fir-type2" or something like that.
> 
> (FWIW, my signal processing textbook describes Type I, II, III, IV FIR filters
> but doesn't say anything about "wideband" FIR filters.)

Oops, didn't read Jonathan's response first, so disregard this comment.
Jonathan Santos Jan. 14, 2025, 12:44 a.m. UTC | #6
On 01/12, Jonathan Cameron wrote:
> On Sat, 11 Jan 2025 19:50:18 -0300
> Jonathan Santos <jonath4nns@gmail.com> wrote:
> 
> > On 01/07, David Lechner wrote:
> > > On 1/7/25 9:24 AM, Jonathan Santos wrote:  
> > > > The Wideband Low Ripple FIR filter is used for AD7768-1 Driver.
> > > > Document wideband filter option into filter_type_avaialable  
> > > 
> > > s/avaialable/available/
> > >   
> > > > attribute.
> > > > 
> > > > Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> > > > ---
> > > >  Documentation/ABI/testing/sysfs-bus-iio | 2 ++
> > > >  1 file changed, 2 insertions(+)
> > > > 
> > > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > > > index f83bd6829285..c4c21a7bfba1 100644
> > > > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > > > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > > > @@ -2291,6 +2291,8 @@ Description:
> > > >  		* "sinc3+pf2" - Sinc3 + device specific Post Filter 2.
> > > >  		* "sinc3+pf3" - Sinc3 + device specific Post Filter 3.
> > > >  		* "sinc3+pf4" - Sinc3 + device specific Post Filter 4.
> > > > +		* "wideband" - FIR filter with wideband low ripple passband  
> > > 
> > > I think "fir" would be a more specific filter type name than "wideband". (i.e.
> > > there are wikipedia pages for sinc and FIR filters, but not one for "wideband"
> > > filters)
> > >   
> > 
> > Isn't "fir" a bit too generic for this case? Since Wideband here is a class of a FIR filter.
> > Maybe something like "wideband-fir" or "fir-wideband" would work better?
> 
> 
> Not sure FIR is even useful. That's just a particular filter architecture, not
> related directly to the characteristics userspace cares about.
> You can sometimes at least build a very similar response from an IIR filter.
> The sinc ones describe the pattern they let through, FIR isn't that specific.
> So I'd not mention FIR anywhere.
> 

So is "wideband" ok for this situation? Removing the FIR mention.

> > 
> > > > +		  and sharp transition band.
> > > >  
> > > >  What:		/sys/.../events/in_proximity_thresh_either_runningperiod
> > > >  KernelVersion:	6.6  
> > >   
>
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index f83bd6829285..c4c21a7bfba1 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -2291,6 +2291,8 @@  Description:
 		* "sinc3+pf2" - Sinc3 + device specific Post Filter 2.
 		* "sinc3+pf3" - Sinc3 + device specific Post Filter 3.
 		* "sinc3+pf4" - Sinc3 + device specific Post Filter 4.
+		* "wideband" - FIR filter with wideband low ripple passband
+		  and sharp transition band.
 
 What:		/sys/.../events/in_proximity_thresh_either_runningperiod
 KernelVersion:	6.6