From: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com> To: jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, michal.simek@xilinx.com, git@xilinx.com, linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: anandash@xilinx.com, Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com> Subject: [PATCH v2] iio: core: Fix IIO_VAL_FRACTIONAL calculation for negative values Date: Wed, 26 Aug 2020 11:14:36 -0700 [thread overview] Message-ID: <1598465676-28912-1-git-send-email-anand.ashok.dumbre@xilinx.com> (raw) Fixes IIO_VAL_FRACTIONAL for case when the result is negative and exponent is 0. example: if the result is -0.75, tmp0 will be 0 and tmp1 = 75 This causes the output to lose sign because of %d in snprintf which works for tmp0 <= -1. Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com> --- changes since v1: Changed -%d to -0 to make the fix clearer. Removed the email footer. Updated the commit description with an example -- drivers/iio/industrialio-core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index cdcd16f1..a239fa2 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -592,6 +592,7 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type, { unsigned long long tmp; int tmp0, tmp1; + s64 tmp2; bool scale_db = false; switch (type) { @@ -614,10 +615,13 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type, else return scnprintf(buf, len, "%d.%09u", vals[0], vals[1]); case IIO_VAL_FRACTIONAL: - tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]); + tmp2 = div_s64((s64)vals[0] * 1000000000LL, vals[1]); tmp1 = vals[1]; tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1); - return scnprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); + if ((tmp2 < 0) && (tmp0 == 0)) + return snprintf(buf, len, "-0.%09u", abs(tmp1)); + else + return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); case IIO_VAL_FRACTIONAL_LOG2: tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]); tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1); -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com> To: jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, michal.simek@xilinx.com, git@xilinx.com, linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: anandash@xilinx.com, Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com> Subject: [PATCH v2] iio: core: Fix IIO_VAL_FRACTIONAL calculation for negative values Date: Wed, 26 Aug 2020 11:14:36 -0700 [thread overview] Message-ID: <1598465676-28912-1-git-send-email-anand.ashok.dumbre@xilinx.com> (raw) Fixes IIO_VAL_FRACTIONAL for case when the result is negative and exponent is 0. example: if the result is -0.75, tmp0 will be 0 and tmp1 = 75 This causes the output to lose sign because of %d in snprintf which works for tmp0 <= -1. Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com> --- changes since v1: Changed -%d to -0 to make the fix clearer. Removed the email footer. Updated the commit description with an example -- drivers/iio/industrialio-core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index cdcd16f1..a239fa2 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -592,6 +592,7 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type, { unsigned long long tmp; int tmp0, tmp1; + s64 tmp2; bool scale_db = false; switch (type) { @@ -614,10 +615,13 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type, else return scnprintf(buf, len, "%d.%09u", vals[0], vals[1]); case IIO_VAL_FRACTIONAL: - tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]); + tmp2 = div_s64((s64)vals[0] * 1000000000LL, vals[1]); tmp1 = vals[1]; tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1); - return scnprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); + if ((tmp2 < 0) && (tmp0 == 0)) + return snprintf(buf, len, "-0.%09u", abs(tmp1)); + else + return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); case IIO_VAL_FRACTIONAL_LOG2: tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]); tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1); -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2020-08-26 18:15 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-26 18:14 Anand Ashok Dumbre [this message] 2020-08-26 18:14 ` [PATCH v2] iio: core: Fix IIO_VAL_FRACTIONAL calculation for negative values Anand Ashok Dumbre 2020-08-29 15:19 ` Jonathan Cameron 2020-08-29 15:19 ` Jonathan Cameron 2020-08-31 8:55 ` Anand Ashok Dumbre 2020-08-31 8:55 ` Anand Ashok Dumbre 2020-08-31 9:51 ` Dan Carpenter 2020-08-31 9:51 ` Dan Carpenter 2020-08-31 9:51 ` Dan Carpenter 2020-08-31 9:51 ` Dan Carpenter 2020-08-27 6:41 kernel test robot
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