From: Alexander Stein <alexander.stein@systec-electronic.com>
To: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>,
Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/1] iio: core: Fix fractional format generation
Date: Thu, 07 Nov 2019 14:54:52 +0100 [thread overview]
Message-ID: <4116142.9TFg0imz4M@ws-140106> (raw)
In-Reply-To: <20190822060607.25339-1-alexander.stein@systec-electronic.com>
Gentle ping
On Thursday, August 22, 2019, 8:06:07 AM CET Alexander Stein wrote:
> In case the result is -0.3252 tmp0 is 0 after the div_s64_rem, so tmp0 is
> non-negative which results in an output of 0.3252.
> Fix this by explicitly handling the negative sign ourselves.
>
> Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
> ---
> Changes in v2:
> * Support vals[0] >= and vals[1] < 0 in IIO_VAL_FRACTIONAL
> * Note: IIO_VAL_FRACTIONAL is untested, as I lack hardware
> * Note2: Currently IIO_VAL_FRACTIONAL is only called with vals[1] from
> in-kernel drivers AFAICS
>
> drivers/iio/industrialio-core.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 245b5844028d..247338142c87 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -568,6 +568,7 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type,
> {
> unsigned long long tmp;
> int tmp0, tmp1;
> + char *sign;
> bool scale_db = false;
>
> switch (type) {
> @@ -593,11 +594,17 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type,
> tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
> tmp1 = vals[1];
> tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
> - return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
> + if (vals[1] < 0) {
> + sign = vals[0] >= 0 ? "-" : "";
> + } else {
> + sign = vals[0] < 0 ? "-" : "";
> + }
> + return snprintf(buf, len, "%s%u.%09u", sign, abs(tmp0), abs(tmp1));
> case IIO_VAL_FRACTIONAL_LOG2:
> + sign = vals[0] < 0 ? "-" : "";
> tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
> tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
> - return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
> + return snprintf(buf, len, "%s%u.%09u", sign, abs(tmp0), abs(tmp1));
> case IIO_VAL_INT_MULTIPLE:
> {
> int i;
>
--
Dipl-Inf. Alexander Stein
SYS TEC electronic AG
Am Windrad 2
08468 Heinsdorfergrund
Germany
Tel: +49-3765-38600-0, Fax: +49-3765-38600-4100
Email : alexander.stein@systec-electronic.com
Internet: http://www.systec-electronic.com
Board of Directors: Dipl.-Ing. Ronald Sieber, Dipl.-Ing. Dirk Bause
Chairman of the Supervisory Board: Dipl.-Phys. Siegmar Schmidt
Commercial registry: Amtsgericht Chemnitz, HRB 32220; USt.-Id Nr.
DE150534010
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next prev parent reply other threads:[~2019-11-07 14:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-22 6:06 [PATCH v2 1/1] iio: core: Fix fractional format generation Alexander Stein
2019-11-07 13:54 ` Alexander Stein [this message]
2019-11-09 11:55 ` Jonathan Cameron
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