| Message ID | 20190822060607.25339-1-alexander.stein@systec-electronic.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/1] iio: core: Fix fractional format generation | expand |
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; >
On Thu, 07 Nov 2019 14:54:52 +0100 Alexander Stein <alexander.stein@systec-electronic.com> wrote: > 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> Apologies. I'd missed this v2 entirely for some reason. It looks correct to me, but as Lars had inputs on v1... Lars, could you take a quick look at this v2 and give an ack if you are happy with it. Thanks, Jonathan > > --- > > 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; > > > >
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;
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(-)