[PATCH 5.4 042/177] iio: adc: ad7606: fix reading unnecessary data from device

[Greg Kroah-Hartman]

From: Beniamin Bia <beniamin.bia@xxxxxxxxxx>

commit 341826a065660d1b77d89e6335b6095cd654271c upstream.

When a conversion result is being read from ADC, the driver reads the
number of channels + 1 because it thinks that IIO_CHAN_SOFT_TIMESTAMP
is also a physical channel. This patch fixes this issue.

Fixes: 2985a5d88455 ("staging: iio: adc: ad7606: Move out of staging")
Reported-by: Robert WÃrle <rwoerle@xxxxxxxxx>
Signed-off-by: Beniamin Bia <beniamin.bia@xxxxxxxxxx>
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/iio/adc/ad7606.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iio/adc/ad7606.c
+++ b/drivers/iio/adc/ad7606.c
@@ -85,7 +85,7 @@ err_unlock:
 
 static int ad7606_read_samples(struct ad7606_state *st)
 {
-	unsigned int num = st->chip_info->num_channels;
+	unsigned int num = st->chip_info->num_channels - 1;
 	u16 *data = st->data;
 	int ret;