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Fri, 25 Sep 2026 04:03:29 -0700 (PDT) Received: from fedora ([165.99.41.159]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4887a355826sm6414715f8f.18.2026.09.25.04.03.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Sep 2026 04:03:29 -0700 (PDT) From: Shehryar Ahmad To: jic23@kernel.org Cc: nuno.sa@analog.com, Michael.Hennerich@analog.com, dlechner@baylibre.com, andy@kernel.org, linux@analog.com, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Shehryar Ahmad Subject: [RFC PATCH] iio: adis_buffer: fix buffer ordering for IIO core demultiplexing Date: Fri, 25 Sep 2026 16:02:39 +0500 Message-ID: <20260925110239.59320-1-shehryar.amd@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Jonathan, After issue raised by Sashiko in adis16203 graduation series [1], looking at other drivers if they might have same issue. It appears that the root cause is in adis_buffer.c itself. The library constructs the SPI transaction in channel array order while IIO core demultiplexes in scan_index order. adis16209 and adis16260 have the same mismatched ordering that adis16201/16203 had. Rather than reordering channel arrays in affected driver, would it be sensible to make adis_update_scan_mode() iterate in scan_index order instead of channel array order? Would this be the right approach, or is there something I'm missing? [1]: https://lore.kernel.org/all/20260914015321.7a660ab5@jic23-hlaptop/ Signed-off-by: Shehryar Ahmad --- drivers/iio/imu/adis_buffer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/iio/imu/adis_buffer.c b/drivers/iio/imu/adis_buffer.c index 501da4eae..45200b753 100644 --- a/drivers/iio/imu/adis_buffer.c +++ b/drivers/iio/imu/adis_buffer.c @@ -110,10 +110,10 @@ int adis_update_scan_mode(struct iio_dev *indio_dev, spi_message_add_tail(&adis->xfer[j], &adis->msg); } - chan = indio_dev->channels; - for (i = 0; i < indio_dev->num_channels; i++, chan++) { - if (!test_bit(chan->scan_index, scan_mask)) - continue; + for_each_set_bit(i, scan_mask, iio_get_masklength(indio_dev)) { + chan = iio_find_channel_from_si(indio_dev, i); + if (!chan) + return -EINVAL; if (chan->scan_type.storagebits == 32) *tx++ = cpu_to_be16((chan->address + 2) << 8); *tx++ = cpu_to_be16(chan->address << 8); -- 2.55.0