From: Stefano Brivio <sbrivio@redhat.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Deepak R Varma <mh12gx2825@gmail.com>,
outreachy-kernel@googlegroups.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Daniel Baluta <daniel.baluta@gmail.com>,
kieran.bingham@ideasonboard.com,
Lars-Peter Clausen <lars@metafoo.de>,
Michael Hennerich <Michael.Hennerich@analog.com>,
Jonathan Cameron <jic23@kernel.org>,
Hartmut Knaack <knaack.h@gmx.de>,
Peter Meerwald <pmeerw@pmeerw.net>,
linux-iio <linux-iio@vger.kernel.org>
Subject: Re: [Outreachy kernel] Re: [PATCH v3 3/4] staging: iio: adc: ad7192: get_filter_freq code optimization
Date: Mon, 23 Mar 2020 01:49:35 +0100 [thread overview]
Message-ID: <20200323014935.48048405@elisabeth> (raw)
In-Reply-To: <CAHp75VfC=y1mHW5=ghwdMMZYg=00_a5RB0Phz4j_vM77pehvMA@mail.gmail.com>
Andy,
On Mon, 23 Mar 2020 01:44:20 +0200
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> On Sun, Mar 22, 2020 at 9:57 PM Deepak R Varma <mh12gx2825@gmail.com> wrote:
> >
> > Current implementation of the function ad7192_get_available_filter_freq
> > repeats calculation of output data rate a few times. We can simplify
> > these steps by refactoring out the calculation of fADC. This would also
> > addresses the checkpatch warning of line exceeding 80 character.
>
> I'm not sure you did an equivalent changes. I believe in the original
> code precision is better. Consider low clock frequencies when 10 bit
> right shift may hide some bits of the division.
Note that those bits are eventually "hidden" in the same way later,
despite the different sequence, due to DIV_ROUND_CLOSEST() being used
at every step (both before and after the change) without other
operations occurring. Anyway,
> Care to write a python script to check the precision between old and new code?
yes, that would be nice no matter what.
--
Stefano
next prev parent reply other threads:[~2020-03-23 0:50 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-22 19:53 [PATCH v3 0/4] staging: iio: adc: General code reformatting / cleanup patchset Deepak R Varma
2020-03-22 19:54 ` [PATCH v3 1/4] staging: iio: adc: ad7192: Re-indent enum labels Deepak R Varma
2020-03-24 7:18 ` Ardelean, Alexandru
2020-03-26 8:19 ` Ardelean, Alexandru
2020-03-26 8:22 ` Ardelean, Alexandru
2020-03-22 19:55 ` [PATCH v3 2/4] staging: iio: adc: ad7192: Correct macro names from SYNC to SINC Deepak R Varma
2020-03-22 23:40 ` Andy Shevchenko
2020-03-23 17:50 ` DEEPAK VARMA
2020-03-26 8:20 ` Ardelean, Alexandru
2020-03-22 19:56 ` [PATCH v3 3/4] staging: iio: adc: ad7192: get_filter_freq code optimization Deepak R Varma
2020-03-22 23:44 ` Andy Shevchenko
2020-03-23 0:49 ` Stefano Brivio [this message]
2020-03-23 9:28 ` [Outreachy kernel] " Andy Shevchenko
2020-03-23 12:15 ` Stefano Brivio
2020-03-23 17:52 ` DEEPAK VARMA
2020-03-24 8:06 ` Ardelean, Alexandru
2020-03-25 17:38 ` DEEPAK VARMA
2020-03-25 19:37 ` Andy Shevchenko
2020-03-25 19:59 ` Stefano Brivio
2020-03-26 8:15 ` Ardelean, Alexandru
2020-03-22 19:57 ` [PATCH v3 4/4] staging: iio: adc: ad7280a: Add comments to clarify stringified arguments Deepak R Varma
2020-03-24 8:07 ` Ardelean, Alexandru
2020-03-28 13:28 ` Jonathan Cameron
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