[PATCH v4 0/2] iio: imu: inv_icm42600: add hwfifo watermark attributes

[PATCH v4 0/2] iio: imu: inv_icm42600: add hwfifo watermark attributes

[Jean-Baptiste Maneyrol via B4 Relay]

Add hwfifo_watermark_* buffer attributes.

There is a preliminary patch for reordering includes first.

Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
---
Changes in v4:
- Rework headers fix to just reorder includes but for all driver
  sources.
- Link to v3: https://patch.msgid.link/20260624-inv-icm42600-add-buffer-hwfifo_attributes-v3-0-5d9a4c662f50@tdk.com

Changes in v3:
- Add a preparatory patch for reordering includes.
- Use IIO_DEVICE_ATTR_RO.
- Link to v2: https://patch.msgid.link/20260624-inv-icm42600-add-buffer-hwfifo_attributes-v2-1-12675259e688@tdk.com

Changes in v2:
- Delete trailing comma after NULL terminator
- Link to v1: https://patch.msgid.link/20260623-inv-icm42600-add-buffer-hwfifo_attributes-v1-1-d190800e60de@tdk.com

To: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
To: Jonathan Cameron <jic23@kernel.org>
To: David Lechner <dlechner@baylibre.com>
To: Nuno Sá <nuno.sa@analog.com>
To: Andy Shevchenko <andy@kernel.org>
Cc: linux-iio@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

---
Jean-Baptiste Maneyrol (2):
      iio: imu: inv_icm42600: reorder all driver headers
      iio: imu: inv_icm42600: add buffer hwfifo watermark attributes

 drivers/iio/imu/inv_icm42600/inv_icm42600.h        | 10 +++--
 drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c  | 18 +++++----
 drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c | 43 ++++++++++++++++++++--
 drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h |  3 +-
 drivers/iio/imu/inv_icm42600/inv_icm42600_core.c   | 12 +++---
 drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c   | 16 ++++----
 drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c    |  8 ++--
 drivers/iio/imu/inv_icm42600/inv_icm42600_spi.c    |  8 ++--
 drivers/iio/imu/inv_icm42600/inv_icm42600_temp.c   |  3 +-
 9 files changed, 84 insertions(+), 37 deletions(-)
---
base-commit: cc746297b23e89bd5df9f91f3a0ca209e8991763
change-id: 20260622-inv-icm42600-add-buffer-hwfifo_attributes-aced0415e341

Best regards,
--  
Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>

[PATCH v4 1/2] iio: imu: inv_icm42600: reorder all driver headers

[Jean-Baptiste Maneyrol via B4 Relay]

From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>

Reorder headers includes following linux rules.

Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
---
 drivers/iio/imu/inv_icm42600/inv_icm42600.h        |  8 +++++---
 drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c  | 13 +++++++------
 drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c |  7 ++++---
 drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h |  2 +-
 drivers/iio/imu/inv_icm42600/inv_icm42600_core.c   | 12 ++++++------
 drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c   | 11 ++++++-----
 drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c    |  8 ++++----
 drivers/iio/imu/inv_icm42600/inv_icm42600_spi.c    |  8 ++++----
 drivers/iio/imu/inv_icm42600/inv_icm42600_temp.c   |  3 ++-
 9 files changed, 39 insertions(+), 33 deletions(-)

diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600.h b/drivers/iio/imu/inv_icm42600/inv_icm42600.h
index c8b48a5c5ed0..2ab863c9d53a 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600.h
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600.h
@@ -6,13 +6,15 @@
 #ifndef INV_ICM42600_H_
 #define INV_ICM42600_H_
 
-#include <linux/bits.h>
 #include <linux/bitfield.h>
-#include <linux/regmap.h>
+#include <linux/bits.h>
 #include <linux/mutex.h>
-#include <linux/regulator/consumer.h>
 #include <linux/pm.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
 #include <linux/iio/iio.h>
+
 #include <linux/iio/common/inv_sensors_timestamp.h>
 
 #include "inv_icm42600_buffer.h"
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
index 532d5fdffaf8..87471e8c9bc7 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
@@ -3,25 +3,26 @@
  * Copyright (C) 2020 Invensense, Inc.
  */
 
-#include <linux/kernel.h>
+#include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/minmax.h>
 #include <linux/mutex.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
-#include <linux/delay.h>
-#include <linux/math64.h>
-#include <linux/minmax.h>
 #include <linux/units.h>
 
 #include <linux/iio/buffer.h>
-#include <linux/iio/common/inv_sensors_timestamp.h>
 #include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/kfifo_buf.h>
 
+#include <linux/iio/common/inv_sensors_timestamp.h>
+
 #include "inv_icm42600.h"
-#include "inv_icm42600_temp.h"
 #include "inv_icm42600_buffer.h"
+#include "inv_icm42600_temp.h"
 
 #define INV_ICM42600_ACCEL_CHAN(_modifier, _index, _ext_info)		\
 	{								\
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
index 68a395758031..26817158ec78 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
@@ -3,18 +3,19 @@
  * Copyright (C) 2020 Invensense, Inc.
  */
 
-#include <linux/kernel.h>
+#include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/kernel.h>
 #include <linux/minmax.h>
 #include <linux/mutex.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
-#include <linux/delay.h>
 
 #include <linux/iio/buffer.h>
-#include <linux/iio/common/inv_sensors_timestamp.h>
 #include <linux/iio/iio.h>
 
+#include <linux/iio/common/inv_sensors_timestamp.h>
+
 #include "inv_icm42600.h"
 #include "inv_icm42600_buffer.h"
 
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
index ffca4da1e249..6ab1eb1a0051 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h
@@ -6,8 +6,8 @@
 #ifndef INV_ICM42600_BUFFER_H_
 #define INV_ICM42600_BUFFER_H_
 
-#include <linux/kernel.h>
 #include <linux/bits.h>
+#include <linux/kernel.h>
 
 struct inv_icm42600_state;
 
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c
index 76eb22488e5f..dc97d8a274e3 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_core.c
@@ -3,18 +3,18 @@
  * Copyright (C) 2020 Invensense, Inc.
  */
 
-#include <linux/kernel.h>
-#include <linux/device.h>
-#include <linux/module.h>
-#include <linux/slab.h>
 #include <linux/delay.h>
-#include <linux/mutex.h>
+#include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
-#include <linux/regulator/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/pm_runtime.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
 
 #include <linux/iio/iio.h>
 
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
index 11339ddf1da3..ea8aa64a3f33 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
@@ -3,22 +3,23 @@
  * Copyright (C) 2020 Invensense, Inc.
  */
 
-#include <linux/kernel.h>
+#include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
 #include <linux/mutex.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
-#include <linux/delay.h>
-#include <linux/math64.h>
 
 #include <linux/iio/buffer.h>
-#include <linux/iio/common/inv_sensors_timestamp.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/kfifo_buf.h>
 
+#include <linux/iio/common/inv_sensors_timestamp.h>
+
 #include "inv_icm42600.h"
-#include "inv_icm42600_temp.h"
 #include "inv_icm42600_buffer.h"
+#include "inv_icm42600_temp.h"
 
 #define INV_ICM42600_GYRO_CHAN(_modifier, _index, _ext_info)		\
 	{								\
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c
index 99d37ac53bbe..f422523207ee 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c
@@ -3,13 +3,13 @@
  * Copyright (C) 2020 InvenSense, Inc.
  */
 
-#include <linux/kernel.h>
 #include <linux/device.h>
-#include <linux/module.h>
-#include <linux/mod_devicetable.h>
 #include <linux/i2c.h>
-#include <linux/regmap.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
 #include <linux/property.h>
+#include <linux/regmap.h>
 
 #include "inv_icm42600.h"
 
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_spi.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_spi.c
index 13e2e7d38638..ec8dac9f24aa 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_spi.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_spi.c
@@ -3,13 +3,13 @@
  * Copyright (C) 2020 InvenSense, Inc.
  */
 
-#include <linux/kernel.h>
 #include <linux/device.h>
-#include <linux/module.h>
+#include <linux/kernel.h>
 #include <linux/mod_devicetable.h>
-#include <linux/spi/spi.h>
-#include <linux/regmap.h>
+#include <linux/module.h>
 #include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
 
 #include "inv_icm42600.h"
 
diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_temp.c b/drivers/iio/imu/inv_icm42600/inv_icm42600_temp.c
index 727b03d541a5..7f80bda471c3 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_temp.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_temp.c
@@ -3,11 +3,12 @@
  * Copyright (C) 2020 Invensense, Inc.
  */
 
-#include <linux/kernel.h>
 #include <linux/device.h>
+#include <linux/kernel.h>
 #include <linux/mutex.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
+
 #include <linux/iio/iio.h>
 
 #include "inv_icm42600.h"

-- 
2.54.0

[PATCH v4 2/2] iio: imu: inv_icm42600: add buffer hwfifo watermark attributes

[Jean-Baptiste Maneyrol via B4 Relay]

From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>

Add hwfifo_watermark/min/max/enabled buffer attributes.
Hardware FIFO is always enabled and used.

Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
---
 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 | 36 ++++++++++++++++++++++
 drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h |  1 +
 drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c   |  5 +--
 5 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600.h b/drivers/iio/imu/inv_icm42600/inv_icm42600.h
index 2ab863c9d53a..b55d993f0264 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600.h
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600.h
@@ -356,6 +356,8 @@ 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 87471e8c9bc7..2421de63f5bf 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c
@@ -1187,8 +1187,9 @@ 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 26817158ec78..c3c2fbd8d9ce 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c
@@ -10,9 +10,11 @@
 #include <linux/mutex.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
+#include <linux/stringify.h>
 
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
 
 #include <linux/iio/common/inv_sensors_timestamp.h>
 
@@ -438,6 +440,40 @@ const struct iio_buffer_setup_ops inv_icm42600_buffer_ops = {
 	.postdisable = inv_icm42600_buffer_postdisable,
 };
 
+static ssize_t hwfifo_watermark_show(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_RO(hwfifo_watermark, 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 6ab1eb1a0051..3b81dba4b7c4 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 ea8aa64a3f33..881612a8e92d 100644
--- a/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
+++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c
@@ -773,8 +773,9 @@ 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);
 

-- 
2.54.0

Re: [PATCH v4 1/2] iio: imu: inv_icm42600: reorder all driver headers

[Andy Shevchenko]

On Thu, Jun 25, 2026 at 02:24:52PM +0200, Jean-Baptiste Maneyrol via B4 Relay wrote:

> Reorder headers includes following linux rules.

Strictly speaking 'linux rules' should be 'the Linux kernel IIO subsystem
preferences'.

Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
(haven't I given this?)

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 1/2] iio: imu: inv_icm42600: reorder all driver headers

[Jonathan Cameron]

On Thu, 25 Jun 2026 17:26:08 +0300
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:

> On Thu, Jun 25, 2026 at 02:24:52PM +0200, Jean-Baptiste Maneyrol via B4 Relay wrote:
> 
> > Reorder headers includes following linux rules.  
> 
> Strictly speaking 'linux rules' should be 'the Linux kernel IIO subsystem
> preferences'.
> 
I tweaked the description and applied.

Thanks

J
> Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> (haven't I given this?)
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> 

Re: [PATCH v4 2/2] iio: imu: inv_icm42600: add buffer hwfifo watermark attributes

[Jonathan Cameron]

On Thu, 25 Jun 2026 14:24:53 +0200
Jean-Baptiste Maneyrol via B4 Relay <devnull+jean-baptiste.maneyrol.tdk.com@kernel.org> wrote:

> From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
> 
> Add hwfifo_watermark/min/max/enabled buffer attributes.
> Hardware FIFO is always enabled and used.
> 
> Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Applied.