[RFC PATCH] iio: adc: ade9000: fix stale data in waveform buffer read

[Giorgi Tchankvetadze]

ade9000_configure_scan() always sets the SPI transfer length to half
the waveform buffer:

  st->xfer[1].len = (st->wfb_nr_samples / 2) * 4;

However, ade9000_iio_push_buffer() iterates over the full
wfb_nr_samples, pushing twice as many samples as were actually read
via SPI. The second half contains stale or uninitialized data from
the rx buffer.

Fix by setting the SPI transfer length to the full waveform buffer
size in ade9000_iio_push_buffer(), since the trigger mode fills the
entire buffer before firing the interrupt.

Fixes: 81de7b4619fc ("iio: adc: add ade9000 support")
Signed-off-by: Giorgi Tchankvetadze <giorgitchankvetadze1997@xxxxxxxxx>
---
 drivers/iio/adc/ade9000.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iio/adc/ade9000.c b/drivers/iio/adc/ade9000.c
index db085dc5e526..c6eb06ef8d37 100644
--- a/drivers/iio/adc/ade9000.c
+++ b/drivers/iio/adc/ade9000.c
@@ -804,6 +804,8 @@ static int ade9000_iio_push_buffer(struct iio_dev *indio_dev)
 
 	guard(mutex)(&st->lock);
 
+	st->xfer[1].len = st->wfb_nr_samples * 4;
+
 	ret = spi_sync(st->spi, &st->spi_msg);
 	if (ret) {
 		dev_err_ratelimited(&st->spi->dev,
-- 
2.52.0