From: Thomas Betker <thomas.betker@rohde-schwarz.com>
Date: Wed, 15 Apr 2015 19:11:50 +0000 (+0200)
Subject: iio: adc: xilinx: Fix VREFN sign
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=97ffae1d30c3f6ceee67d5b0d3e540c08c13c744;p=linux-beck.git

iio: adc: xilinx: Fix VREFN sign

The VREFN channel is bipolar, not unipolar. Small negative values do
occur (e.g., -1mV), and unsigned conversion maps them incorrectly to
large positive values (about +1V), so fix this.

Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---

diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index 6fa629b3c168..ce93bd8e3f68 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -997,7 +997,7 @@ static const struct iio_event_spec xadc_voltage_events[] = {
 	.num_event_specs = (_alarm) ? ARRAY_SIZE(xadc_voltage_events) : 0, \
 	.scan_index = (_scan_index), \
 	.scan_type = { \
-		.sign = 'u', \
+		.sign = ((_addr) == XADC_REG_VREFN) ? 's' : 'u', \
 		.realbits = 12, \
 		.storagebits = 16, \
 		.shift = 4, \