v4.19.13 snapshot.
diff --git a/drivers/iio/imu/adis16400_buffer.c b/drivers/iio/imu/adis16400_buffer.c
new file mode 100644
index 0000000..e70a533
--- /dev/null
+++ b/drivers/iio/imu/adis16400_buffer.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/export.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#include "adis16400.h"
+
+int adis16400_update_scan_mode(struct iio_dev *indio_dev,
+ const unsigned long *scan_mask)
+{
+ struct adis16400_state *st = iio_priv(indio_dev);
+ struct adis *adis = &st->adis;
+ unsigned int burst_length;
+ u8 *tx;
+
+ if (st->variant->flags & ADIS16400_NO_BURST)
+ return adis_update_scan_mode(indio_dev, scan_mask);
+
+ kfree(adis->xfer);
+ kfree(adis->buffer);
+
+ /* All but the timestamp channel */
+ burst_length = (indio_dev->num_channels - 1) * sizeof(u16);
+ if (st->variant->flags & ADIS16400_BURST_DIAG_STAT)
+ burst_length += sizeof(u16);
+
+ adis->xfer = kcalloc(2, sizeof(*adis->xfer), GFP_KERNEL);
+ if (!adis->xfer)
+ return -ENOMEM;
+
+ adis->buffer = kzalloc(burst_length + sizeof(u16), GFP_KERNEL);
+ if (!adis->buffer)
+ return -ENOMEM;
+
+ tx = adis->buffer + burst_length;
+ tx[0] = ADIS_READ_REG(ADIS16400_GLOB_CMD);
+ tx[1] = 0;
+
+ adis->xfer[0].tx_buf = tx;
+ adis->xfer[0].bits_per_word = 8;
+ adis->xfer[0].len = 2;
+ adis->xfer[1].rx_buf = adis->buffer;
+ adis->xfer[1].bits_per_word = 8;
+ adis->xfer[1].len = burst_length;
+
+ spi_message_init(&adis->msg);
+ spi_message_add_tail(&adis->xfer[0], &adis->msg);
+ spi_message_add_tail(&adis->xfer[1], &adis->msg);
+
+ return 0;
+}
+
+irqreturn_t adis16400_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct adis16400_state *st = iio_priv(indio_dev);
+ struct adis *adis = &st->adis;
+ u32 old_speed_hz = st->adis.spi->max_speed_hz;
+ void *buffer;
+ int ret;
+
+ if (!adis->buffer)
+ return -ENOMEM;
+
+ if (!(st->variant->flags & ADIS16400_NO_BURST) &&
+ st->adis.spi->max_speed_hz > ADIS16400_SPI_BURST) {
+ st->adis.spi->max_speed_hz = ADIS16400_SPI_BURST;
+ spi_setup(st->adis.spi);
+ }
+
+ ret = spi_sync(adis->spi, &adis->msg);
+ if (ret)
+ dev_err(&adis->spi->dev, "Failed to read data: %d\n", ret);
+
+ if (!(st->variant->flags & ADIS16400_NO_BURST)) {
+ st->adis.spi->max_speed_hz = old_speed_hz;
+ spi_setup(st->adis.spi);
+ }
+
+ if (st->variant->flags & ADIS16400_BURST_DIAG_STAT)
+ buffer = adis->buffer + sizeof(u16);
+ else
+ buffer = adis->buffer;
+
+ iio_push_to_buffers_with_timestamp(indio_dev, buffer,
+ pf->timestamp);
+
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}