[PATCH V3 5/9] iio: imu: inv_icm42607: Add Temperature Support in icm42607

[Chris Morgan <macroalpha82@gmail.com>]

From: Chris Morgan <macromorgan@hotmail.com>

Add functions for reading temperature sensor data.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/iio/imu/inv_icm42607/inv_icm42607.h   |  3 +
 .../iio/imu/inv_icm42607/inv_icm42607_core.c  | 17 ++++
 .../iio/imu/inv_icm42607/inv_icm42607_temp.c  | 81 +++++++++++++++++++
 .../iio/imu/inv_icm42607/inv_icm42607_temp.h  | 30 +++++++
 4 files changed, 131 insertions(+)
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c
 create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_temp.h

diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607.h b/drivers/iio/imu/inv_icm42607/inv_icm42607.h
index 5530fd3bc03f..086848c8fd3b 100644
--- a/drivers/iio/imu/inv_icm42607/inv_icm42607.h
+++ b/drivers/iio/imu/inv_icm42607/inv_icm42607.h
@@ -433,6 +433,9 @@ extern const struct dev_pm_ops inv_icm42607_pm_ops;
 
 u32 inv_icm42607_odr_to_period(enum inv_icm42607_odr odr);
 
+int inv_icm42607_set_temp_conf(struct inv_icm42607_state *st, bool enable,
+			       unsigned int *sleep_ms);
+
 int inv_icm42607_debugfs_reg(struct iio_dev *indio_dev, unsigned int reg,
 			     unsigned int writeval, unsigned int *readval);
 
diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c b/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
index 344071089042..735a262dc103 100644
--- a/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
+++ b/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
@@ -164,6 +164,23 @@ static int inv_icm42607_set_pwr_mgmt0(struct inv_icm42607_state *st,
 	return 0;
 }
 
+int inv_icm42607_set_temp_conf(struct inv_icm42607_state *st, bool enable,
+			       unsigned int *sleep_ms)
+{
+	unsigned int val;
+	int ret;
+
+	val = INV_ICM42607_TEMP_CONFIG0_FILTER(INV_ICM42607_FILTER_BW_34HZ);
+	ret = regmap_update_bits(st->map, INV_ICM42607_REG_TEMP_CONFIG0,
+				 INV_ICM42607_TEMP_CONFIG0_FILTER_MASK, val);
+	if (ret)
+		return ret;
+
+	return inv_icm42607_set_pwr_mgmt0(st, st->conf.gyro.mode,
+					  st->conf.accel.mode, enable,
+					  sleep_ms);
+}
+
 int inv_icm42607_debugfs_reg(struct iio_dev *indio_dev, unsigned int reg,
 			     unsigned int writeval, unsigned int *readval)
 {
diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c b/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c
new file mode 100644
index 000000000000..b42eb78cd960
--- /dev/null
+++ b/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 InvenSense, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/iio/iio.h>
+
+#include "inv_icm42607.h"
+#include "inv_icm42607_temp.h"
+
+static int inv_icm42607_temp_read(struct inv_icm42607_state *st, s16 *temp)
+{
+	struct device *dev = regmap_get_device(st->map);
+	__be16 *raw;
+	int ret;
+
+	PM_RUNTIME_ACQUIRE_AUTOSUSPEND(dev, pm);
+	if (PM_RUNTIME_ACQUIRE_ERR(&pm))
+		return -ENXIO;
+
+	guard(mutex)(&st->lock);
+
+	ret = inv_icm42607_set_temp_conf(st, true, NULL);
+	if (ret)
+		return ret;
+
+	raw = (__be16 *)&st->buffer[0];
+	ret = regmap_bulk_read(st->map, INV_ICM42607_REG_TEMP_DATA1, raw, sizeof(*raw));
+	if (ret)
+		return ret;
+
+	*temp = (s16)be16_to_cpup(raw);
+	if (*temp == INV_ICM42607_DATA_INVALID)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+int inv_icm42607_temp_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct inv_icm42607_state *st = iio_device_get_drvdata(indio_dev);
+	s16 temp;
+	int ret;
+
+	if (chan->type != IIO_TEMP)
+		return -EINVAL;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (!iio_device_claim_direct(indio_dev))
+			return -EBUSY;
+		ret = inv_icm42607_temp_read(st, &temp);
+		iio_device_release_direct(indio_dev);
+		if (ret)
+			return ret;
+		*val = temp;
+		return IIO_VAL_INT;
+	/*
+	 * T°C = (temp / 128) + 25
+	 * Tm°C = 1000 * ((temp * 100 / 12800) + 25)
+	 * scale: 100000 / 12800 ~= 7.8125
+	 * offset: 25000
+	 */
+	case IIO_CHAN_INFO_SCALE:
+		*val = 7;
+		*val2 = 812500;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = 25000;
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.h b/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.h
new file mode 100644
index 000000000000..d0bd6c460ff2
--- /dev/null
+++ b/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2026 InvenSense, Inc.
+ */
+
+#ifndef INV_ICM42607_TEMP_H_
+#define INV_ICM42607_TEMP_H_
+
+#include <linux/iio/iio.h>
+
+#define INV_ICM42607_TEMP_CHAN(_index)				\
+{								\
+	.type = IIO_TEMP,					\
+	.info_mask_separate =					\
+		BIT(IIO_CHAN_INFO_RAW) |			\
+		BIT(IIO_CHAN_INFO_OFFSET) |			\
+		BIT(IIO_CHAN_INFO_SCALE),			\
+	.scan_index = _index,					\
+	.scan_type = {						\
+		.sign = 's',					\
+		.realbits = 16,					\
+		.storagebits = 16,				\
+	},							\
+}
+
+int inv_icm42607_temp_read_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int *val, int *val2, long mask);
+
+#endif
-- 
2.43.0