From: Eva Rachel Retuya <eraretuya@gmail.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>,
linux-iio@vger.kernel.org, Hartmut Knaack <knaack.h@gmx.de>,
Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald <pmeerw@pmeerw.net>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Michael Hennerich <michael.hennerich@analog.com>,
Daniel Baluta <daniel.baluta@gmail.com>,
Alison Schofield <amsfield22@gmail.com>,
Florian Vaussard <florian.vaussard@heig-vd.ch>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 2/4] iio: accel: adxl345_core: Introduce set_mode and data_ready functions
Date: Tue, 2 May 2017 19:46:56 +0800 [thread overview]
Message-ID: <20170502114655.GB3030@Socrates-UM> (raw)
In-Reply-To: <CAHp75VcOqrQ8QKiSLoS4gkREvm8voDsw22EnxRPwtWLJFkQu4g@mail.gmail.com>
On Mon, May 01, 2017 at 02:21:02PM +0300, Andy Shevchenko wrote:
[...]
> Couple of minors below.
> Otherwise, FWIW:
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
>
Hello Andy,
> > +static int adxl345_data_ready(struct adxl345_data *data)
> > +{
> > + struct device *dev = regmap_get_device(data->regmap);
>
> > + int tries = 5;
>
> unsigned int tries = 5;
>
Ack.
> > + u32 val;
> > + int ret;
> > +
> > + do {
>
> > + /*
> > + * 1/ODR + 1.1ms; 11.1ms at ODR of 0.10 Hz
> > + * Sensor currently operates at default ODR of 100 Hz
> > + */
> > + usleep_range(1100, 11100);
>
> From the above comment I can't get why we sleep first then attempt to
> read and not otherwise. Please, elaborate.
>
Before this function is called, the sensor is placed into measurement
mode. The delay is there to account for the "wake-up" time from standby
to measurement mode. So sleep first then attempt to read. In the first
version I was not yet aware of it until I look around in the datasheet
trying to justify how long to delay. I will clarify the comment to make
it more clear.
Thanks,
Eva
> > +
> > + ret = regmap_read(data->regmap, ADXL345_REG_INT_SOURCE, &val);
> > + if (ret < 0)
> > + return ret;
> > + if ((val & ADXL345_INT_DATA_READY) == ADXL345_INT_DATA_READY)
> > + return 0;
> > + } while (--tries);
> > + dev_err(dev, "Data is not yet ready, try again.\n");
> > +
> > + return -EAGAIN;
> > +}
>
> --
> With Best Regards,
> Andy Shevchenko
next prev parent reply other threads:[~2017-05-02 11:47 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-29 7:48 [PATCH v2 0/4] iio: accel: adxl345: Add support for buffered readings Eva Rachel Retuya
2017-04-29 7:48 ` [PATCH v2 1/4] dt-bindings: iio: accel: adxl345: Add optional interrupt-names support Eva Rachel Retuya
2017-04-29 7:48 ` [PATCH v2 2/4] iio: accel: adxl345_core: Introduce set_mode and data_ready functions Eva Rachel Retuya
2017-05-01 0:22 ` Jonathan Cameron
2017-05-01 19:42 ` Andy Shevchenko
2017-05-01 19:48 ` Jonathan Cameron
2017-05-01 20:07 ` Andy Shevchenko
2017-05-01 20:18 ` Jonathan Cameron
2017-05-02 11:39 ` Eva Rachel Retuya
2017-05-02 16:32 ` Jonathan Cameron
2017-05-10 13:07 ` Eva Rachel Retuya
2017-05-01 11:21 ` Andy Shevchenko
2017-05-02 11:46 ` Eva Rachel Retuya [this message]
2017-04-29 7:49 ` [PATCH v2 3/4] iio: accel: adxl345: Setup DATA_READY trigger Eva Rachel Retuya
2017-05-01 0:32 ` Jonathan Cameron
2017-05-02 3:01 ` Rob Herring
2017-05-02 15:59 ` Jonathan Cameron
2017-05-10 14:33 ` Eva Rachel Retuya
2017-05-02 11:59 ` Eva Rachel Retuya
2017-05-01 11:31 ` Andy Shevchenko
2017-05-02 12:15 ` Eva Rachel Retuya
2017-05-02 21:05 ` Andy Shevchenko
2017-05-10 13:24 ` Eva Rachel Retuya
2017-05-14 15:15 ` Jonathan Cameron
2017-05-14 16:08 ` Dmitry Torokhov
2017-05-05 18:26 ` Jonathan Cameron
2017-05-10 13:31 ` Eva Rachel Retuya
2017-04-29 7:49 ` [PATCH v2 4/4] iio: accel: adxl345: Add support for triggered buffer Eva Rachel Retuya
2017-05-01 0:42 ` Jonathan Cameron
2017-05-02 12:23 ` Eva Rachel Retuya
2017-05-02 16:08 ` Jonathan Cameron
2017-05-01 11:24 ` Andy Shevchenko
2017-05-02 12:24 ` Eva Rachel Retuya
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