Add Invensense ICM42607

From: Chris Morgan <[email protected]>

Add the core component of a new inv_icm42607 driver. This includes a few setup functions and the full register definition in the header file.

Signed-off-by Chris Morgan <[email protected]>

---
 drivers/iio/imu/inv_icm42607/inv_icm42607.h   | 334 ++++++++++++++++++
 .../iio/imu/inv_icm42607/inv_icm42607_core.c  | 207 +++++++++++
 2 files changed, 541 insertions(+)
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607.h
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_core.c

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +57 -0

new file mode 100644
index 000000000000..1916e0b08bca
@@ -0,0 +1,334 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2026 InvenSense, Inc.
+ */
+
+#ifndef INV_ICM42607_H_
+#define INV_ICM42607_H_
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/iio/iio.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+enum inv_icm42607_sensor_mode {
+	INV_ICM42607_SENSOR_MODE_OFF,
+	INV_ICM42607_SENSOR_MODE_STANDBY,
+	INV_ICM42607_SENSOR_MODE_LOW_POWER,
+	INV_ICM42607_SENSOR_MODE_LOW_NOISE,
+	INV_ICM42607_SENSOR_MODE_NB
+};
+
+/* gyroscope fullscale values */
+enum inv_icm42607_gyro_fs {
+	INV_ICM42607_GYRO_FS_2000DPS,
+	INV_ICM42607_GYRO_FS_1000DPS,
+	INV_ICM42607_GYRO_FS_500DPS,
+	INV_ICM42607_GYRO_FS_250DPS,
+	INV_ICM42607_GYRO_FS_NB
+};
+
+/* accelerometer fullscale values */
+enum inv_icm42607_accel_fs {
+	INV_ICM42607_ACCEL_FS_16G,
+	INV_ICM42607_ACCEL_FS_8G,
+	INV_ICM42607_ACCEL_FS_4G,
+	INV_ICM42607_ACCEL_FS_2G,
+	INV_ICM42607_ACCEL_FS_NB
+};
+
+/* ODR values */
+enum inv_icm42607_odr {
+	INV_ICM42607_ODR_1600HZ = 5,
+	INV_ICM42607_ODR_800HZ,
+	INV_ICM42607_ODR_400HZ,
+	INV_ICM42607_ODR_200HZ,
+	INV_ICM42607_ODR_100HZ,
+	INV_ICM42607_ODR_50HZ,
+	INV_ICM42607_ODR_25HZ,
+	INV_ICM42607_ODR_12_5HZ,
+	INV_ICM42607_ODR_6_25HZ_LP,
+	INV_ICM42607_ODR_3_125HZ_LP,
+	INV_ICM42607_ODR_1_5625HZ_LP,
+	INV_ICM42607_ODR_NB
+};
+

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +9 -0

+
+typedef int (*inv_icm42607_bus_setup)(struct inv_icm42607_state *);
+
+extern const struct regmap_config inv_icm42607_regmap_config;
+
+int inv_icm42607_core_probe(struct regmap *regmap, const struct inv_icm42607_hw *hw,
+			    inv_icm42607_bus_setup bus_setup);
+
+#endif

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +17 -0

new file mode 100644
index 000000000000..9784709319b9
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 InvenSense, Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/iio/iio.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#include "inv_icm42607.h"
+

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +33 -0

+	ret = regmap_write(st->map, INV_ICM42607_REG_GYRO_CONFIG1, val);
+	if (ret)
+		return ret;
+
+	val = FIELD_PREP(INV_ICM42607_ACCEL_CONFIG1_FILTER_MASK,
+			 conf->accel.filter);
+	ret = regmap_write(st->map, INV_ICM42607_REG_ACCEL_CONFIG1, val);
+	if (ret)
+		return ret;
+
+	st->conf = *conf;
+
+	return 0;
+}
+
+/**
+ *  inv_icm42607_setup() - check and setup chip
+ *  @st:	driver internal state
+ *  @bus_setup:	callback for setting up bus specific registers
+ *
+ *  Returns 0 on success, a negative error code otherwise.
+ */
+static int inv_icm42607_setup(struct inv_icm42607_state *st,
+			      inv_icm42607_bus_setup bus_setup)
+{
+	const struct device *dev = regmap_get_device(st->map);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(st->map, INV_ICM42607_REG_WHOAMI, &val);
+	if (ret)
+		return ret;
+

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +26 -0

+
+	ret = regmap_read_poll_timeout(st->map, INV_ICM42607_REG_INT_STATUS,
+				       val, val & INV_ICM42607_INT_STATUS_RESET_DONE,
+				       INV_ICM42607_RESET_TIME_MS * 100,
+				       INV_ICM42607_RESET_TIME_MS * 1000);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "reset error, reset done bit not set\n");
+
+	ret = bus_setup(st);
+	if (ret)
+		return ret;
+
+	ret = regmap_set_bits(st->map, INV_ICM42607_REG_INTF_CONFIG0,
+			      INV_ICM42607_INTF_CONFIG0_SENSOR_DATA_ENDIAN);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(st->map, INV_ICM42607_REG_INTF_CONFIG1,
+				 INV_ICM42607_INTF_CONFIG1_CLKSEL_MASK,
+				 INV_ICM42607_INTF_CONFIG1_CLKSEL_PLL);
+	if (ret)
+		return ret;
+
+	return inv_icm42607_set_conf(st, st->hw->conf);
+}
 

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +4 -0

+
+	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+	if (!st)
+		return -ENOMEM;

Quoted 7 lines · On Fri, 15 May 2026 08:00:08 -0500 Chris Morgan <[email protected]> wrote:

From: Chris Morgan <[email protected]>

Add the core component of a new inv_icm42607 driver. This includes a few setup functions and the full register definition in the header file.

Signed-off-by Chris Morgan <[email protected]>

Sashiko led you into the weeks with irq request return values. It was less broken in v6 :(

As to it's other comments on checking for line high/low values (0x00 / 0xFF) for whoami is something we don't normally bother with but you could if you like. I'm fairly sure we've had both those values turn up as valid in some devices in the past.

Otherwise just trivial stuff I noticed whilst having a fresh read through. All stuff I might have tweaked whilst applying or just let through but seeing as you are going to be doing a v8, please take a look.

Jonathan

Quoted 72 lines

---
 drivers/iio/imu/inv_icm42607/inv_icm42607.h   | 334 ++++++++++++++++++
 .../iio/imu/inv_icm42607/inv_icm42607_core.c  | 207 +++++++++++
 2 files changed, 541 insertions(+)
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607.h
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_core.c

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +57 -0

new file mode 100644
index 000000000000..1916e0b08bca
@@ -0,0 +1,334 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2026 InvenSense, Inc.
+ */
+
+#ifndef INV_ICM42607_H_
+#define INV_ICM42607_H_
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/iio/iio.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+enum inv_icm42607_sensor_mode {
+	INV_ICM42607_SENSOR_MODE_OFF,
+	INV_ICM42607_SENSOR_MODE_STANDBY,
+	INV_ICM42607_SENSOR_MODE_LOW_POWER,
+	INV_ICM42607_SENSOR_MODE_LOW_NOISE,
+	INV_ICM42607_SENSOR_MODE_NB
+};
+
+/* gyroscope fullscale values */
+enum inv_icm42607_gyro_fs {
+	INV_ICM42607_GYRO_FS_2000DPS,
+	INV_ICM42607_GYRO_FS_1000DPS,
+	INV_ICM42607_GYRO_FS_500DPS,
+	INV_ICM42607_GYRO_FS_250DPS,
+	INV_ICM42607_GYRO_FS_NB
+};
+
+/* accelerometer fullscale values */
+enum inv_icm42607_accel_fs {
+	INV_ICM42607_ACCEL_FS_16G,
+	INV_ICM42607_ACCEL_FS_8G,
+	INV_ICM42607_ACCEL_FS_4G,
+	INV_ICM42607_ACCEL_FS_2G,
+	INV_ICM42607_ACCEL_FS_NB
+};
+
+/* ODR values */
+enum inv_icm42607_odr {
+	INV_ICM42607_ODR_1600HZ = 5,
+	INV_ICM42607_ODR_800HZ,
+	INV_ICM42607_ODR_400HZ,
+	INV_ICM42607_ODR_200HZ,
+	INV_ICM42607_ODR_100HZ,
+	INV_ICM42607_ODR_50HZ,
+	INV_ICM42607_ODR_25HZ,
+	INV_ICM42607_ODR_12_5HZ,
+	INV_ICM42607_ODR_6_25HZ_LP,
+	INV_ICM42607_ODR_3_125HZ_LP,
+	INV_ICM42607_ODR_1_5625HZ_LP,
+	INV_ICM42607_ODR_NB
+};
+

drivers/iio/imu/inv_icm42607/inv_icm42607.h line 67

Quoted 10 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +10 -0

+enum inv_icm42607_filter_bw {
+	/* Low-Noise mode sensor data filter (bandwidth) */
+	INV_ICM42607_FILTER_BYPASS,
+	INV_ICM42607_FILTER_BW_180HZ,
+	INV_ICM42607_FILTER_BW_121HZ,
+	INV_ICM42607_FILTER_BW_73HZ,
+	INV_ICM42607_FILTER_BW_53HZ,
+	INV_ICM42607_FILTER_BW_34HZ,
+	INV_ICM42607_FILTER_BW_25HZ,
+	INV_ICM42607_FILTER_BW_16HZ

That isn't a terminating entry so it should have a , Rules on this are a bit obscure - but basically _NB type entries should never have a , anything else should - even if it's a register field enum where we know all values are there.

Quoted 1 line

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +1 -0

+};

drivers/iio/imu/inv_icm42607/inv_icm42607.h line 325

Quoted 8 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +8 -0

+/* Sleep times required by the driver */
+#define INV_ICM42607_POWER_UP_TIME_US			100000
+#define INV_ICM42607_RESET_TIME_MS			1
+#define INV_ICM42607_ACCEL_STARTUP_TIME_MS		20
+#define INV_ICM42607_GYRO_STARTUP_TIME_MS		60
+#define INV_ICM42607_GYRO_STOP_TIME_MS			150
+#define INV_ICM42607_TEMP_STARTUP_TIME_MS		14
+#define INV_ICM42607_SUSPEND_DELAY_MS			2000

Can we have spec references for these? We often hit problems later with devices that are a little bit slow and no one is sure if it's because the sleeps are wrong or device is actually out of spec. Hence it is useful to be able to quickly check these.

Quoted 33 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +9 -0

+
+typedef int (*inv_icm42607_bus_setup)(struct inv_icm42607_state *);
+
+extern const struct regmap_config inv_icm42607_regmap_config;
+
+int inv_icm42607_core_probe(struct regmap *regmap, const struct inv_icm42607_hw *hw,
+			    inv_icm42607_bus_setup bus_setup);
+
+#endif

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +17 -0

new file mode 100644
index 000000000000..9784709319b9
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 InvenSense, Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/iio/iio.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#include "inv_icm42607.h"
+

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 27

Quoted 10 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +10 -0

+static int inv_icm42607_set_conf(struct inv_icm42607_state *st,
+				 const struct inv_icm42607_conf *conf)
+{
+	unsigned int val;
+	int ret;
+
+	val = FIELD_PREP(INV_ICM42607_PWR_MGMT0_GYRO_MODE_MASK,
+			 conf->gyro.mode);
+	val |= FIELD_PREP(INV_ICM42607_PWR_MGMT0_ACCEL_MODE_MASK,
+			  conf->accel.mode);

As below - I'm fine with these going on one line (first is 80 chars, second just over)

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 32

Quoted 5 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +5 -0

+	/*
+	 * No temperature enable reg in datasheet, but BSP driver
+	 * selected RC oscillator clock in LP mode when temperature
+	 * was disabled.
+	 */

	/*
	 * No temperature enable reg in datasheet, but BSP driver selected 
	 * RC oscillator clock in LP mode when temperature was disabled.
	 */

Basically go up to 80 chars. Here I think keeping RC oscillator on one line is a good idea though.

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 40

Quoted 8 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +8 -0

+	if (!conf->temp_en)
+		val |= INV_ICM42607_PWR_MGMT0_ACCEL_LP_CLK_SEL;
+	ret = regmap_write(st->map, INV_ICM42607_REG_PWR_MGMT0, val);
+	if (ret)
+		return ret;
+
+	val = FIELD_PREP(INV_ICM42607_GYRO_CONFIG0_FS_SEL_MASK,
+			 conf->gyro.fs);

It's under 80 chars on one line so don't wrap.

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 42

Quoted 2 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +2 -0

+	val |= FIELD_PREP(INV_ICM42607_GYRO_CONFIG0_ODR_MASK,
+			  conf->gyro.odr);

As is this.

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 54

Quoted 12 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +12 -0

+	ret = regmap_write(st->map, INV_ICM42607_REG_GYRO_CONFIG0, val);
+	if (ret)
+		return ret;
+
+	val = FIELD_PREP(INV_ICM42607_ACCEL_CONFIG0_FS_SEL_MASK, conf->accel.fs);
+	val |= FIELD_PREP(INV_ICM42607_ACCEL_CONFIG0_ODR_MASK, conf->accel.odr);
+	ret = regmap_write(st->map, INV_ICM42607_REG_ACCEL_CONFIG0, val);
+	if (ret)
+		return ret;
+
+	val = FIELD_PREP(INV_ICM42607_GYRO_CONFIG1_FILTER_MASK,
+			 conf->gyro.filter);

Whilst this one and next are a tiny bit over 80 chars, if you want to I don't mind those being a little long as single lines.

Quoted 41 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +41 -0

+	ret = regmap_write(st->map, INV_ICM42607_REG_GYRO_CONFIG1, val);
+	if (ret)
+		return ret;
+
+	val = FIELD_PREP(INV_ICM42607_ACCEL_CONFIG1_FILTER_MASK,
+			 conf->accel.filter);
+	ret = regmap_write(st->map, INV_ICM42607_REG_ACCEL_CONFIG1, val);
+	if (ret)
+		return ret;
+
+	st->conf = *conf;
+
+	return 0;
+}
+
+/**
+ *  inv_icm42607_setup() - check and setup chip
+ *  @st:	driver internal state
+ *  @bus_setup:	callback for setting up bus specific registers
+ *
+ *  Returns 0 on success, a negative error code otherwise.
+ */
+static int inv_icm42607_setup(struct inv_icm42607_state *st,
+			      inv_icm42607_bus_setup bus_setup)
+{
+	const struct device *dev = regmap_get_device(st->map);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(st->map, INV_ICM42607_REG_WHOAMI, &val);
+	if (ret)
+		return ret;
+
+	if (val != st->hw->whoami)
+		dev_warn(dev, "invalid whoami %#02x expected %#02x (%s)\n",
+			 val, st->hw->whoami, st->hw->name);
+
+	ret = regmap_write(st->map, INV_ICM42607_REG_SIGNAL_PATH_RESET,
+			   INV_ICM42607_SIGNAL_PATH_RESET_SOFT_RESET);
+	if (ret)
+		return ret;

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 97

Quoted 2 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +2 -0

+
+	fsleep(1000);

Do we need an explicit sleep here, or is the idea just to save on a read that can't succeed in the poll that follows? I'd be tempted to drop this if it's not absolutely needed just to avoid explaining it. This isn't fast path code. If we need to leave the device alone after reset for a bit then a datasheet reference is needed.

Quoted 27 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +26 -0

+
+	ret = regmap_read_poll_timeout(st->map, INV_ICM42607_REG_INT_STATUS,
+				       val, val & INV_ICM42607_INT_STATUS_RESET_DONE,
+				       INV_ICM42607_RESET_TIME_MS * 100,
+				       INV_ICM42607_RESET_TIME_MS * 1000);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "reset error, reset done bit not set\n");
+
+	ret = bus_setup(st);
+	if (ret)
+		return ret;
+
+	ret = regmap_set_bits(st->map, INV_ICM42607_REG_INTF_CONFIG0,
+			      INV_ICM42607_INTF_CONFIG0_SENSOR_DATA_ENDIAN);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(st->map, INV_ICM42607_REG_INTF_CONFIG1,
+				 INV_ICM42607_INTF_CONFIG1_CLKSEL_MASK,
+				 INV_ICM42607_INTF_CONFIG1_CLKSEL_PLL);
+	if (ret)
+		return ret;
+
+	return inv_icm42607_set_conf(st, st->hw->conf);
+}
 

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 154

Quoted 10 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +10 -0

+int inv_icm42607_core_probe(struct regmap *regmap, const struct inv_icm42607_hw *hw,
+			    inv_icm42607_bus_setup bus_setup)
+{
+	struct device *dev = regmap_get_device(regmap);
+	struct fwnode_handle *fwnode = dev_fwnode(dev);
+	struct inv_icm42607_state *st;
+	int irq;
+	int ret;
+
+	irq = fwnode_irq_get_byname(fwnode, "INT1");

Trivial but if fwnode is only used here (I didn't check later patches) then put the dev_fwnode() inline.

I've never really understood why we don't have device_ variant of that - perhaps because it's hard to come up with a clear name.

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 156

Quoted 2 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +2 -0

+	if (!(irq > 0))
+		return dev_err_probe(dev, -EINVAL, "Unable to get INT1 interrupt\n");

I assume this is in response to sashiko saying fwnode_irq_get_byname() can in some corner cases (where I suspect things are broken enough the system probably won't boot)
return 0. If we are actually going to defend against that then you need
to special case it. New sashiko review correctly reports this breaks probe deferal if say the interrupt chip driver hasn't loaded yet.

	if (irq < 0) {
		return dev_err_probe(dev, irq, ...);
	if (irq == 0)
		/* Odd corner case... */
		return dev_err_probe(dev, -EINVAL, ...);

However I'm deeply suspicious of whether the code paths that return 0 can happen in practice. Given you have a suitable DT, can you try seeing if you can actually make it return 0 by messing around with the interrupt mappings?

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c line 160

Quoted 5 lines

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c new file +4 -0

+
+	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+	if (!st)
+		return -ENOMEM;

Quoted 19 lines · Jonathan Cameron

Quoted 7 lines · On Fri, 15 May 2026 08:00:08 -0500 Chris Morgan <[email protected]> wrote:

From: Chris Morgan <[email protected]>

Add the core component of a new inv_icm42607 driver. This includes a few setup functions and the full register definition in the header file.

Signed-off-by Chris Morgan <[email protected]>

Sashiko led you into the weeks with irq request return values. It was less broken in v6 :(

As to it's other comments on checking for line high/low values (0x00 / 0xFF) for whoami is something we don't normally bother with but you could if you like. I'm fairly sure we've had both those values turn up as valid in some devices in the past.

Quoted 5 lines

Otherwise just trivial stuff I noticed whilst having a fresh read through. All stuff I might have tweaked whilst applying or just let through but seeing as you are going to be doing a v8, please take a look.

Jonathan

I think I'll ignore that comment about the high-low values, but it does make valid points about using the wrong call to invalidate the regmap cache and also the wrong call to set the SPI_MODE_3 stuff.

All in all I'll try to post another version in another day or two with the recommended fixes (as best I can) and see if it still complains. I'm expecting a few complaints like the 0x00/0xFF or some stuff about "keeping the temp sensor enabled" which is a non-issue per the datasheet. Hopefully I'm near the finish line either way.

Quoted 16 lines

Quoted 14 lines

  
---
 drivers/iio/imu/inv_icm42607/inv_icm42607.h   | 334 ++++++++++++++++++
 .../iio/imu/inv_icm42607/inv_icm42607_core.c  | 207 +++++++++++
 2 files changed, 541 insertions(+)
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607.h
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_core.c

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +0 -0

new file mode 100644
index 000000000000..1916e0b08bca

Quoted 13 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h line 325

Quoted 8 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +8 -0

+/* Sleep times required by the driver */
+#define INV_ICM42607_POWER_UP_TIME_US			100000
+#define INV_ICM42607_RESET_TIME_MS			1
+#define INV_ICM42607_ACCEL_STARTUP_TIME_MS		20
+#define INV_ICM42607_GYRO_STARTUP_TIME_MS		60
+#define INV_ICM42607_GYRO_STOP_TIME_MS			150
+#define INV_ICM42607_TEMP_STARTUP_TIME_MS		14
+#define INV_ICM42607_SUSPEND_DELAY_MS			2000  

Can we have spec references for these? We often hit problems later with devices that are a little bit slow and no one is sure if it's because the sleeps are wrong or device is actually out of spec. Hence it is useful to be able to quickly check these.

I took these from the driver I basically copied wholesale and changed the registers for according to the datasheet, but I didn't take a very close look at these (which I am now).

The POWER_UP_TIME_US, assuming it's the same as "Supply Ramp Time" from the datasheet is 100ms which matches. Likewise, the "Start-up time for register read/write" listed under "Power-On Reset" shows 1ms, which matches.

The ACCEL_STARTUP_TIME_MS should probably be 10ms, and the GYRO_STARTUP_TIME_MS should probably be 30ms. I don't see a startup time listed for the temperature sensor but I do see "Stabilization Time" which lists 77us. Gyro stop time and suspend delay time I cannot find a reference for... logically if those values are needed I think they should likely be the same as the gyro start time and power up time, respectively right?

The values I am referencing now appear under the electrical characteristics section (section 3) of the datasheet for both the icm42607p (my test devices, over i2c) and the icm42607(c).

Quoted 19 lines

Quoted 19 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +19 -0

+static int inv_icm42607_setup(struct inv_icm42607_state *st,
+			      inv_icm42607_bus_setup bus_setup)
+{
+	const struct device *dev = regmap_get_device(st->map);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(st->map, INV_ICM42607_REG_WHOAMI, &val);
+	if (ret)
+		return ret;
+
+	if (val != st->hw->whoami)
+		dev_warn(dev, "invalid whoami %#02x expected %#02x (%s)\n",
+			 val, st->hw->whoami, st->hw->name);
+
+	ret = regmap_write(st->map, INV_ICM42607_REG_SIGNAL_PATH_RESET,
+			   INV_ICM42607_SIGNAL_PATH_RESET_SOFT_RESET);
+	if (ret)
+		return ret;

Quoted 9 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h

Quoted 2 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +2 -0

+
+	fsleep(1000);  

Do we need an explicit sleep here, or is the idea just to save on a read that can't succeed in the poll that follows? I'd be tempted to drop this if it's not absolutely needed just to avoid explaining it. This isn't fast path code. If we need to leave the device alone after reset for a bit then a datasheet reference is needed.

Data sheet only really says that the time required after a *hard* reset is 1ms, it honestly doesn't say anything about a soft reset.

I also thought I got rid of the read_poll_timeout, since I'm already waiting 1ms... if you think this fsleep is needed or not I'll defer to you.

Honestly this whole path thing got messed up when we wanted to code for 3 wire SPI. For 3 wire I need to make sure I enable it as soon as the reset completes, so it's probably not even right here. I need to add bus_setup() before the read not after. So to support 3-wire it needs to go:
bus_setup()
whoami check
reset
wait (maybe)
bus_setup() again
check int_status (if we can after the bus_setup)
do the rest

whereas if we explicitly say no 3-wire then we can drop the first bus setup and use regmap_read_poll_timeout to get the status.

Quoted 7 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h

Quoted 6 lines

drivers/iio/imu/inv_icm42607/inv_icm42607.h new file +4 -0

+
+	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+	if (!st)
+		return -ENOMEM;  

I sincerely appreciate all your help on this. Here I was thinking this would be easy and I could focus on a joystick/LED driver next... how wrong I was!

Chris

From: Chris Morgan <[email protected]>

Add I2C and SPI driver support for InvenSense ICM-42607 devices. Add necessary Kconfig and Makefile to allow building of (incomplete) driver.

Signed-off-by Chris Morgan <[email protected]>

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +5 -0

+	 */
+	ret = bus_setup(st);
+	if (ret)
+		return ret;
+
 	ret = regmap_read(st->map, INV_ICM42607_REG_WHOAMI, &val);
 	if (ret)
 		return ret;

@@ -94,20 +159,27 @@ static int inv_icm42607_setup(struct inv_icm42607_state *st,
 	if (ret)
 		return ret;
 

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +0 -5

-	ret = regmap_read_poll_timeout(st->map, INV_ICM42607_REG_INT_STATUS,
-				       val, val & INV_ICM42607_INT_STATUS_RESET_DONE,
-				       INV_ICM42607_RESET_TIME_MS * 100,
-				       INV_ICM42607_RESET_TIME_MS * 1000);
-	if (ret)

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +3 -0

+		return dev_err_probe(dev, -EIO,
+				     "reset error, reset done bit not set\n");
+
 	ret = regmap_set_bits(st->map, INV_ICM42607_REG_INTF_CONFIG0,
 			      INV_ICM42607_INTF_CONFIG0_SENSOR_DATA_ENDIAN);
 	if (ret)
 

drivers/iio/imu/inv_icm42607/inv_icm42607_spi.c new file +17 -0

new file mode 100644
index 000000000000..49438fa6f867
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 InvenSense, Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "inv_icm42607.h"
+
+static int inv_icm42607_spi_bus_setup(struct inv_icm42607_state *st)
+{
+	const struct device *dev = regmap_get_device(st->map);

drivers/iio/imu/inv_icm42607/inv_icm42607_spi.c new file +29 -0

+	if (ret)
+		return ret;
+
+	ret = regmap_clear_bits(st->map, INV_ICM42607_REG_INTF_CONFIG1,
+				INV_ICM42607_INTF_CONFIG1_I3C_DDR_EN |
+				INV_ICM42607_INTF_CONFIG1_I3C_SDR_EN);
+	if (ret)
+		return ret;
+
+	val = FIELD_PREP(INV_ICM42607_DRIVE_CONFIG3_SPI_MASK,
+			 INV_ICM42607_SLEW_RATE_INF_2NS);
+	ret = regmap_update_bits(st->map, INV_ICM42607_REG_DRIVE_CONFIG3,
+				 INV_ICM42607_DRIVE_CONFIG3_SPI_MASK, val);
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(st->map, INV_ICM42607_REG_INTF_CONFIG0,
+				  INV_ICM42607_INTF_CONFIG0_UI_SIFS_CFG_MASK,
+				  INV_ICM42607_INTF_CONFIG0_UI_SIFS_CFG_I2C_DIS);
+}
+
+static int inv_icm42607_probe(struct spi_device *spi)
+{
+	const struct inv_icm42607_hw *hw;
+	struct regmap *regmap;
+
+	hw = spi_get_device_match_data(spi);
+	if (!hw)
+		return dev_err_probe(&spi->dev, -ENODEV,

drivers/iio/imu/inv_icm42607/inv_icm42607_spi.c new file +1 -0

+}

From: Chris Morgan <[email protected]>

Add power management support for the ICM42607 device driver.

Signed-off-by Chris Morgan <[email protected]>

---
 drivers/iio/imu/inv_icm42607/inv_icm42607.h   |  12 ++
 .../iio/imu/inv_icm42607/inv_icm42607_core.c  | 143 ++++++++++++++++++
 .../iio/imu/inv_icm42607/inv_icm42607_i2c.c   |   1 +
 .../iio/imu/inv_icm42607/inv_icm42607_spi.c   |   1 +
 4 files changed, 157 insertions(+)

drivers/iio/imu/inv_icm42607/inv_icm42607.h +0 -0

index 2c20e95b237a..5f37999e39a5 100644

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +0 -0

index 1088c5c7076f..e27ad0319a12 100644
 
 static int inv_icm42607_set_conf(struct inv_icm42607_state *st,
 				 const struct inv_icm42607_conf *conf)
 {

@@ -198,11 +255,15 @@ static int inv_icm42607_enable_vddio_reg(struct inv_icm42607_state *st)
 {
 	int ret;

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +5 -0

 }
 
 
+static int inv_icm42607_suspend(struct device *dev)
+{
+	struct inv_icm42607_state *st = dev_get_drvdata(dev);
+	int ret;
+

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +13 -0

+
+	guard(mutex)(&st->lock);
+
+	ret = inv_icm42607_set_pwr_mgmt0(st, INV_ICM42607_SENSOR_MODE_OFF,
+					 INV_ICM42607_SENSOR_MODE_OFF, false,
+					 NULL);
+	if (ret)
+		return ret;
+
+	inv_icm42607_disable_vddio_reg(st);
+
+	return 0;
+}

From: Chris Morgan <[email protected]>

Add all FIFO parsing and reading functions to support inv_icm42607 hardware.

Signed-off-by Chris Morgan <[email protected]>

---
 drivers/iio/imu/inv_icm42607/Makefile         |   1 +
 drivers/iio/imu/inv_icm42607/inv_icm42607.h   |  27 +
 .../imu/inv_icm42607/inv_icm42607_buffer.c    | 483 ++++++++++++++++++
 .../imu/inv_icm42607/inv_icm42607_buffer.h    |  93 ++++
 .../iio/imu/inv_icm42607/inv_icm42607_core.c  |  54 +-
 5 files changed, 657 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_buffer.c
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_buffer.h

drivers/iio/imu/inv_icm42607/Makefile +1 -0

index be109102e203..3c9d08509793 100644
@@ -2,6 +2,7 @@
 
 obj-$(CONFIG_INV_ICM42607) += inv-icm42607.o
 inv-icm42607-y += inv_icm42607_core.o
+inv-icm42607-y += inv_icm42607_buffer.o
 
 obj-$(CONFIG_INV_ICM42607_I2C) += inv-icm42607-i2c.o
 inv-icm42607-i2c-y += inv_icm42607_i2c.o

drivers/iio/imu/inv_icm42607/inv_icm42607.h +4 -0

index 5f37999e39a5..b00ee6a4d451 100644
@@ -14,6 +14,10 @@
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 
+#include <linux/iio/common/inv_sensors_timestamp.h>
+
+#include "inv_icm42607_buffer.h"
+
 /* serial bus slew rates */
 enum inv_icm42607_slew_rate {
 	INV_ICM42607_SLEW_RATE_20_60NS,

drivers/iio/imu/inv_icm42607/inv_icm42607_buffer.c new file +15 -0

new file mode 100644
index 000000000000..74e5213d9267
 
 
+
+static int inv_icm42607_buffer_postdisable(struct iio_dev *indio_dev)
+{
+	struct inv_icm42607_state *st = iio_device_get_drvdata(indio_dev);
+	struct device *dev = regmap_get_device(st->map);
+	unsigned int sensor;
+	unsigned int *watermark;
+	unsigned int sleep_temp = 0;
+	unsigned int sleep_sensor = 0;
+	unsigned int sleep;
+	int ret;
+
+	if (indio_dev == st->indio_gyro) {
+		sensor = INV_ICM42607_SENSOR_GYRO;
+		watermark = &st->fifo.watermark.gyro;

drivers/iio/imu/inv_icm42607/inv_icm42607_buffer.c new file +5 -0

+	if (ret)
+		goto out_unlock;
+
+	*watermark = 0;
+	ret = inv_icm42607_buffer_update_watermark(st);

drivers/iio/imu/inv_icm42607/inv_icm42607_buffer.c new file +13 -0

+
+	pm_runtime_put_autosuspend(dev);
+
+	return ret;
+}
+
+const struct iio_buffer_setup_ops inv_icm42607_buffer_ops = {
+	.preenable = inv_icm42607_buffer_preenable,
+	.postenable = inv_icm42607_buffer_postenable,
+	.predisable = inv_icm42607_buffer_predisable,
+	.postdisable = inv_icm42607_buffer_postdisable,
+};
+

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +1 -0

index e27ad0319a12..d5885fc3f7da 100644
@@ -15,6 +15,7 @@
 #include <linux/regulator/consumer.h>
 
 #include "inv_icm42607.h"
+#include "inv_icm42607_buffer.h"
 
 static bool inv_icm42607_is_volatile_reg(struct device *dev, unsigned int reg)
 {

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +14 -0

+		625000,
+		/* 800Hz */
+		1250000,
+		/* 400Hz */
+		2500000,
+		/* 200Hz */
+		5000000,
+		/* 100 Hz */
+		10000000,
+		/* 50Hz */
+		20000000,
+		/* 25Hz */
+		40000000,
+		/* 12.5Hz */

drivers/iio/imu/inv_icm42607/inv_icm42607_core.c +3 -0

+
+	return odr_periods[odr];
+}

From: Chris Morgan <[email protected]>

Add icm42607 accelerometer sensor for icm42607.

Signed-off-by Chris Morgan <[email protected]>