This is a note to let you know that I've just added the patch titled
iio: adc: spmi-vadc: Fix overflow in output value
to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iio-adc-spmi-vadc-fix-overflow-in-output-value.patch
and it can be found in the queue-4.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 937125aca00e0478c4024afe58bc620a7bbe2a93 Mon Sep 17 00:00:00 2001
From: "Ivan T. Ivanov" <ivan.ivanov@xxxxxxxxxx>
Date: Fri, 17 Apr 2015 17:51:08 +0300
Subject: iio: adc: spmi-vadc: Fix overflow in output value
normalization
From: "Ivan T. Ivanov" <ivan.ivanov@xxxxxxxxxx>
commit 937125aca00e0478c4024afe58bc620a7bbe2a93 upstream.
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@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iio/adc/qcom-spmi-vadc.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- 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_pr
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_pr
voltage = voltage * prescale->den;
- return voltage / prescale->num;
+ return div64_s64(voltage, prescale->num);
}
static int vadc_decimation_from_dt(u32 value)
Patches currently in stable-queue which might be from ivan.ivanov@xxxxxxxxxx are
queue-4.0/iio-adc-spmi-vadc-fix-overflow-in-output-value.patch
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