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authorAlexandru Tachici <alexandru.tachici@analog.com>2019-12-20 12:07:19 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-01-13 12:08:14 +0100
commitd7857e4ee1ba69732b16c73b2f2dde83ecd78ee4 (patch)
tree7f5250cbaa42a5585d79f77376cc285c50bf3e7b
parentb3a987b0264d3ddbb24293ebff10eddfc472f653 (diff)
downloadlinux-d7857e4ee1ba69732b16c73b2f2dde83ecd78ee4.tar.gz
iio: adc: ad7124: Fix DT channel configuration
This patch fixes device tree channel configuration. ad7124 driver reads channels configuration from the device tree. It expects to find channel specifications as child nodes. Before this patch ad7124 driver assumed that the child nodes are parsed by for_each_available_child_of_node in the order 0,1,2,3... This is wrong and the real order of the children can be seen by running: dtc -I fs /sys/firmware/devicetree/base on the machine. For example, running this on an rpi 3B+ yields the real children order: 4,2,0,7,5,3,1,6 Before this patch the driver assigned the channel configuration like this: - 0 <- 4 - 1 <- 2 - 2 <- 0 ........ For example, the symptoms can be observed by connecting the 4th channel to a 1V tension and then reading the in_voltage0-voltage19_raw sysfs (multiplied of course by the scale) one would see that channel 0 measures 1V and channel 4 measures only noise. Now the driver uses the reg property of each child in order to correctly identify to which channel the parsed configuration belongs to. Fixes b3af341bbd966: ("iio: adc: Add ad7124 support") Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/iio/adc/ad7124.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index 3f03abf100b5..306bf15023a7 100644
--- a/drivers/iio/adc/ad7124.c
+++ b/drivers/iio/adc/ad7124.c
@@ -494,13 +494,11 @@ static int ad7124_of_parse_channel_config(struct iio_dev *indio_dev,
st->channel_config[channel].buf_negative =
of_property_read_bool(child, "adi,buffered-negative");
- *chan = ad7124_channel_template;
- chan->address = channel;
- chan->scan_index = channel;
- chan->channel = ain[0];
- chan->channel2 = ain[1];
-
- chan++;
+ chan[channel] = ad7124_channel_template;
+ chan[channel].address = channel;
+ chan[channel].scan_index = channel;
+ chan[channel].channel = ain[0];
+ chan[channel].channel2 = ain[1];
}
return 0;