| Message ID | 1429282268-30501-1-git-send-email-ivan.ivanov@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | Andy Gross |
| Headers | show |
On 17/04/15 15:51, Ivan T. Ivanov wrote: > With 'dx' equal to 0.625V and 15 bit ADC, calculations overflow > when difference against GND is ~20% of the ADC range. Fix this. > > Signed-off-by: Ivan T. Ivanov <ivan.ivanov@linaro.org> Applied to the fixes-togreg branch of iio.git and marked for stable. Thanks, Jonathan > > --- > drivers/iio/adc/qcom-spmi-vadc.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c > index 3211729..0c4618b 100644 > --- a/drivers/iio/adc/qcom-spmi-vadc.c > +++ b/drivers/iio/adc/qcom-spmi-vadc.c > @@ -18,6 +18,7 @@ > #include <linux/iio/iio.h> > #include <linux/interrupt.h> > #include <linux/kernel.h> > +#include <linux/math64.h> > #include <linux/module.h> > #include <linux/of.h> > #include <linux/platform_device.h> > @@ -471,11 +472,11 @@ static s32 vadc_calibrate(struct vadc_priv *vadc, > const struct vadc_channel_prop *prop, u16 adc_code) > { > const struct vadc_prescale_ratio *prescale; > - s32 voltage; > + s64 voltage; > > voltage = adc_code - vadc->graph[prop->calibration].gnd; > voltage *= vadc->graph[prop->calibration].dx; > - voltage = voltage / vadc->graph[prop->calibration].dy; > + voltage = div64_s64(voltage, vadc->graph[prop->calibration].dy); > > if (prop->calibration == VADC_CALIB_ABSOLUTE) > voltage += vadc->graph[prop->calibration].dx; > @@ -487,7 +488,7 @@ static s32 vadc_calibrate(struct vadc_priv *vadc, > > voltage = voltage * prescale->den; > > - return voltage / prescale->num; > + return div64_s64(voltage, prescale->num); > } > > static int vadc_decimation_from_dt(u32 value) > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c index 3211729..0c4618b 100644 --- a/drivers/iio/adc/qcom-spmi-vadc.c +++ b/drivers/iio/adc/qcom-spmi-vadc.c @@ -18,6 +18,7 @@ #include <linux/iio/iio.h> #include <linux/interrupt.h> #include <linux/kernel.h> +#include <linux/math64.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> @@ -471,11 +472,11 @@ static s32 vadc_calibrate(struct vadc_priv *vadc, const struct vadc_channel_prop *prop, u16 adc_code) { const struct vadc_prescale_ratio *prescale; - s32 voltage; + s64 voltage; voltage = adc_code - vadc->graph[prop->calibration].gnd; voltage *= vadc->graph[prop->calibration].dx; - voltage = voltage / vadc->graph[prop->calibration].dy; + voltage = div64_s64(voltage, vadc->graph[prop->calibration].dy); if (prop->calibration == VADC_CALIB_ABSOLUTE) voltage += vadc->graph[prop->calibration].dx; @@ -487,7 +488,7 @@ static s32 vadc_calibrate(struct vadc_priv *vadc, voltage = voltage * prescale->den; - return voltage / prescale->num; + return div64_s64(voltage, prescale->num); } static int vadc_decimation_from_dt(u32 value)
With 'dx' equal to 0.625V and 15 bit ADC, calculations overflow when difference against GND is ~20% of the ADC range. Fix this. Signed-off-by: Ivan T. Ivanov <ivan.ivanov@linaro.org> --- drivers/iio/adc/qcom-spmi-vadc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html