[PATCH] iio: imu: inv_icm42600: add buffer hwfifo watermark attributes
From: Jean-Baptiste Maneyrol via B4 Relay
Date: Tue Jun 23 2026 - 06:16:14 EST
From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@xxxxxxx>
Add hwfifo_watermark/min/max/enabled buffer attributes.
Hardware FIFO is always enabled and used.
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@xxxxxxx>
---
drivers/iio/imu/inv_icm42600/inv_icm42600.h | 2 ++
drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c | 5 +--
drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c | 37 ++++++++++++++++++++++
drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h | 1 +
drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c | 5 +--
5 files changed, 46 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600.h b/drivers/iio/imu/inv_icm42600/inv_icm42600.h
index c8b48a5c5ed0..7c9b63584a05 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600.h
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600.h
@@ -354,6 +354,8 @@ struct inv_icm42600_sensor_state {
cpu_to_le16((_wm) & GENMASK(11, 0))
/* FIFO is 2048 bytes, let 12 samples for reading latency */
#define INV_ICM42600_FIFO_WATERMARK_MAX (2048 - 12 * 16)
+/* INV_ICM42600_FIFO_WATERMARK_MAX / 8 = 232 */
+#define INV_ICM42600_FIFO_WATERMARK_MAX_SAMPLES 232
#define INV_ICM42600_REG_INT_CONFIG1 0x0064
#define INV_ICM42600_INT_CONFIG1_TPULSE_DURATION BIT(6)
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
index 532d5fdffaf8..1ab73953bef6 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
@@ -1186,8 +1186,9 @@ struct iio_dev *inv_icm42600_accel_init(struct inv_icm42600_state *st)
indio_dev->num_channels = ARRAY_SIZE(inv_icm42600_accel_channels);
indio_dev->available_scan_masks = inv_icm42600_accel_scan_masks;
- ret = devm_iio_kfifo_buffer_setup(dev, indio_dev,
- &inv_icm42600_buffer_ops);
+ ret = devm_iio_kfifo_buffer_setup_ext(dev, indio_dev,
+ &inv_icm42600_buffer_ops,
+ inv_icm42600_buffer_attrs);
if (ret)
return ERR_PTR(ret);
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
index 68a395758031..0399cce94545 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
@@ -10,10 +10,12 @@
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/delay.h>
+#include <linux/stringify.h>
#include <linux/iio/buffer.h>
#include <linux/iio/common/inv_sensors_timestamp.h>
#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
#include "inv_icm42600.h"
#include "inv_icm42600_buffer.h"
@@ -437,6 +439,41 @@ const struct iio_buffer_setup_ops inv_icm42600_buffer_ops = {
.postdisable = inv_icm42600_buffer_postdisable,
};
+static ssize_t inv_icm42600_buffer_get_watermark(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct inv_icm42600_state *st = iio_device_get_drvdata(indio_dev);
+ unsigned int wm;
+
+ guard(mutex)(&st->lock);
+
+ if (indio_dev == st->indio_accel)
+ wm = st->fifo.watermark.eff_accel;
+ else if (indio_dev == st->indio_gyro)
+ wm = st->fifo.watermark.eff_gyro;
+ else
+ return -EINVAL;
+
+ return sysfs_emit(buf, "%u\n", wm);
+}
+
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_min, "1");
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_max,
+ __stringify(INV_ICM42600_FIFO_WATERMARK_MAX_SAMPLES));
+static IIO_DEVICE_ATTR(hwfifo_watermark, 0444, inv_icm42600_buffer_get_watermark,
+ NULL, 0);
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_enabled, "1");
+
+const struct iio_dev_attr *inv_icm42600_buffer_attrs[] = {
+ &iio_dev_attr_hwfifo_watermark_min,
+ &iio_dev_attr_hwfifo_watermark_max,
+ &iio_dev_attr_hwfifo_watermark,
+ &iio_dev_attr_hwfifo_enabled,
+ NULL,
+};
+
int inv_icm42600_buffer_fifo_read(struct inv_icm42600_state *st,
unsigned int max)
{
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
index ffca4da1e249..522e158accc9 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
@@ -79,6 +79,7 @@ ssize_t inv_icm42600_fifo_decode_packet(const void *packet, const void **accel,
const void **timestamp, unsigned int *odr);
extern const struct iio_buffer_setup_ops inv_icm42600_buffer_ops;
+extern const struct iio_dev_attr *inv_icm42600_buffer_attrs[];
int inv_icm42600_buffer_init(struct inv_icm42600_state *st);
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
index 11339ddf1da3..7d4f6701f124 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
@@ -772,8 +772,9 @@ struct iio_dev *inv_icm42600_gyro_init(struct inv_icm42600_state *st)
indio_dev->available_scan_masks = inv_icm42600_gyro_scan_masks;
indio_dev->setup_ops = &inv_icm42600_buffer_ops;
- ret = devm_iio_kfifo_buffer_setup(dev, indio_dev,
- &inv_icm42600_buffer_ops);
+ ret = devm_iio_kfifo_buffer_setup_ext(dev, indio_dev,
+ &inv_icm42600_buffer_ops,
+ inv_icm42600_buffer_attrs);
if (ret)
return ERR_PTR(ret);
---
base-commit: cc746297b23e89bd5df9f91f3a0ca209e8991763
change-id: 20260622-inv-icm42600-add-buffer-hwfifo_attributes-aced0415e341
Best regards,
--
Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@xxxxxxx>