linux-iio.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Crt Mori <cmo@melexis.com>
Cc: Jonathan Cameron <jic23@kernel.org>,
	linux-iio <linux-iio@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 3/5] iio:temperature:mlx90632: Convert polling while loop to do-while
Date: Thu, 13 Aug 2020 14:24:23 +0300	[thread overview]
Message-ID: <CAHp75Vd+3SopKog6uhSKoOLn+tECsQfs7kRbJsrMZEbNRpk8bQ@mail.gmail.com> (raw)
In-Reply-To: <CAKv63uv=b60B9RXBJF4HEhMOowu-qbGrv7LsmJVvkkERSida-A@mail.gmail.com>

On Thu, Aug 13, 2020 at 2:14 PM Crt Mori <cmo@melexis.com> wrote:
>
> On Thu, 13 Aug 2020 at 13:03, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> >
> > On Thu, Aug 13, 2020 at 10:53 AM Crt Mori <cmo@melexis.com> wrote:
> > >
> > > Reduce number of lines and improve readability to convert polling while
> > > loops to do-while. The iopoll.h interface was not used, because we
> > > require more than 20ms timeout, because time for sensor to perform a
> > > measurement is around 10ms and it needs to perform measurements for each
> > > channel (which currently is 3).
> >
> > I don't see how it prevents using iopoll.h. It uses usleep_range()
> > under the hood in the same way you did here, but open coded.
> >
>
> One loop is indeed 10ms and that is not the problem, the problem is
> that timeout is at least 3 calls of this data ready (3 channels), so
> that is at minimum 30ms of timeout, or it could even be 4 in worse
> case scenario and that is outside of the range for usleep to measure.
> So in case of the other loop, where we wait 200ms for channel refresh
> it is also out of scope. Timeout should be in number of tries or in
> msleep range if you ask me.

I still didn't buy it. You have in both cases usleep_range(). Why in
your case it's okay and in regmap_read_poll_timeout() is not?

> > ...
> >
> > > -       while (tries-- > 0) {
> > > +       do {
> > >                 ret = regmap_read(data->regmap, MLX90632_REG_STATUS,
> > >                                   &reg_status);
> > >                 if (ret < 0)
> > >                         return ret;
> > > -               if (reg_status & MLX90632_STAT_DATA_RDY)
> > > -                       break;
> > >                 usleep_range(10000, 11000);
> > > -       }
> > > +       } while (!(reg_status & MLX90632_STAT_DATA_RDY) && tries--);
> > >
> > >         if (tries < 0) {
> > >                 dev_err(&data->client->dev, "data not ready");

-- 
With Best Regards,
Andy Shevchenko

  reply	other threads:[~2020-08-13 11:24 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-13  7:51 [PATCH v5 0/5] iio: temperature: mlx90632: Add extended calibration calculations Crt Mori
2020-08-13  7:51 ` [PATCH v5 1/5] iio:temperature:mlx90632: Reduce number of equal calulcations Crt Mori
2020-08-13  7:51 ` [PATCH v5 2/5] iio:temperature:mlx90632: Add kerneldoc to the internal struct Crt Mori
2020-08-13 10:54   ` Andy Shevchenko
2020-08-13  7:51 ` [PATCH v5 3/5] iio:temperature:mlx90632: Convert polling while loop to do-while Crt Mori
2020-08-13 11:03   ` Andy Shevchenko
2020-08-13 11:13     ` Crt Mori
2020-08-13 11:24       ` Andy Shevchenko [this message]
2020-08-13 13:03         ` Crt Mori
2020-08-13 19:40           ` Andy Shevchenko
2020-08-14  7:32             ` Crt Mori
2020-08-14  9:31               ` Andy Shevchenko
2020-08-14  9:42                 ` Crt Mori
2020-08-14 12:11                   ` Andy Shevchenko
2020-08-13  7:51 ` [PATCH v5 4/5] iio:temperature:mlx90632: Adding extended calibration option Crt Mori
2020-08-13 11:06   ` Andy Shevchenko
2020-08-13  7:51 ` [PATCH v5 5/5] iio:temperature:mlx90632: Some stylefixing leftovers Crt Mori
2020-08-13 11:01   ` Andy Shevchenko
2020-08-13 13:11     ` Crt Mori
2020-08-13 19:41       ` Andy Shevchenko
2020-08-16  8:38         ` Jonathan Cameron

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAHp75Vd+3SopKog6uhSKoOLn+tECsQfs7kRbJsrMZEbNRpk8bQ@mail.gmail.com \
    --to=andy.shevchenko@gmail.com \
    --cc=cmo@melexis.com \
    --cc=jic23@kernel.org \
    --cc=linux-iio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --subject='Re: [PATCH v5 3/5] iio:temperature:mlx90632: Convert polling while loop to do-while' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).