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From: Mathieu Othacehe <m.othacehe@gmail.com>
To: Jonathan Cameron <jic23@jic23.retrosnub.co.uk>
Cc: linux-iio@vger.kernel.org, lars@metafoo.de
Subject: Re: isl29501 and multiple calibration registers
Date: Fri, 15 Jun 2018 14:34:08 +0200	[thread overview]
Message-ID: <87po0si5z3.fsf@gmail.com> (raw)
In-Reply-To: <87wov5id5w.fsf@gmail.com>


Hi,

I have another concern about I and Q representation. The formula given
by Renesas to put them under decimal form is:

         (MSB << 8 + LSB) << EXP/100000

Given that EXP is an unsigned 8 bit integer, the maximum value of I and
Q is ~2^255 which can only be represented as a double.

Hence, it is not possible to represent them under in_intensity0_i/q_raw
even using a scale.

Same thing for I and Q calibbias (crosstalk values), the user can not
input such a big number.

How could we proceed about it, would it be ok to represent those values
as EXP << 16 + MSB << 8 + LSB both for raw and calibbias values?

Thanks,

Mathieu

  reply	other threads:[~2018-06-15 12:34 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-25 16:01 isl29501 and multiple calibration registers Mathieu Othacehe
2018-05-27  8:59 ` Jonathan Cameron
2018-05-28 15:38   ` Mathieu Othacehe
2018-06-03 14:38     ` Jonathan Cameron
2018-06-05 10:18       ` Mathieu Othacehe
2018-06-10 13:29         ` Jonathan Cameron
2018-06-11 14:57           ` Mathieu Othacehe
2018-06-15 12:34             ` Mathieu Othacehe [this message]
2018-06-16 17:46               ` Mostly question of whether we should support floating point values from hardware (was Re: isl29501 and multiple calibration registers) Jonathan Cameron
2018-06-27 13:43                 ` Mathieu Othacehe
2018-06-30 17:55                   ` Jonathan Cameron
2018-06-16 17:13             ` isl29501 and multiple calibration registers Jonathan Cameron
2018-06-19 10:24               ` Mathieu Othacehe

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