x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

4 files changed, 707 insertions, 0 deletions

diff --git a/drivers/iio/position/Kconfig b/drivers/iio/position/Kconfig
new file mode 100644
index 000000000..1576a6380
--- /dev/null
+++ b/drivers/iio/position/Kconfig
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Linear and angular position sensors
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "Linear and angular position sensors"
+
+config IQS624_POS
+	tristate "Azoteq IQS624/625 angular position sensors"
+	depends on MFD_IQS62X || COMPILE_TEST
+	help
+	  Say Y here if you want to build support for the Azoteq IQS624
+	  and IQS625 angular position sensors.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called iqs624-pos.
+
+config HID_SENSOR_CUSTOM_INTEL_HINGE
+	depends on HID_SENSOR_HUB
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select HID_SENSOR_IIO_COMMON
+	select HID_SENSOR_IIO_TRIGGER
+	tristate "HID Hinge"
+	help
+	  This sensor present three angles, hinge angel, screen angles
+	  and keyboard angle respect to horizon (ground).
+	  Say yes here to build support for the HID custom
+	  intel hinge sensor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hid-sensor-custom-hinge.
+
+endmenu
diff --git a/drivers/iio/position/Makefile b/drivers/iio/position/Makefile
new file mode 100644
index 000000000..d70902f29
--- /dev/null
+++ b/drivers/iio/position/Makefile
@@ -0,0 +1,8 @@
+#
+# Makefile for IIO linear and angular position sensors
+#
+
+# When adding new entries keep the list in alphabetical order
+
+obj-$(CONFIG_HID_SENSOR_CUSTOM_INTEL_HINGE) += hid-sensor-custom-intel-hinge.o
+obj-$(CONFIG_IQS624_POS)	+= iqs624-pos.o
diff --git a/drivers/iio/position/hid-sensor-custom-intel-hinge.c b/drivers/iio/position/hid-sensor-custom-intel-hinge.c
new file mode 100644
index 000000000..d275bc141
--- /dev/null
+++ b/drivers/iio/position/hid-sensor-custom-intel-hinge.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID Sensors Driver
+ * Copyright (c) 2020, Intel Corporation.
+ */
+#include <linux/hid-sensor-hub.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+
+#include "../common/hid-sensors/hid-sensor-trigger.h"
+
+enum hinge_channel {
+	CHANNEL_SCAN_INDEX_HINGE_ANGLE,
+	CHANNEL_SCAN_INDEX_SCREEN_ANGLE,
+	CHANNEL_SCAN_INDEX_KEYBOARD_ANGLE,
+	CHANNEL_SCAN_INDEX_MAX,
+};
+
+#define CHANNEL_SCAN_INDEX_TIMESTAMP CHANNEL_SCAN_INDEX_MAX
+
+static const u32 hinge_addresses[CHANNEL_SCAN_INDEX_MAX] = {
+	HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(1),
+	HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(2),
+	HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(3)
+};
+
+static const char *const hinge_labels[CHANNEL_SCAN_INDEX_MAX] = { "hinge",
+								  "screen",
+								  "keyboard" };
+
+struct hinge_state {
+	struct iio_dev *indio_dev;
+	struct hid_sensor_hub_attribute_info hinge[CHANNEL_SCAN_INDEX_MAX];
+	struct hid_sensor_hub_callbacks callbacks;
+	struct hid_sensor_common common_attributes;
+	const char *labels[CHANNEL_SCAN_INDEX_MAX];
+	struct {
+		u32 hinge_val[3];
+		aligned_s64 timestamp;
+	} scan;
+
+	int scale_pre_decml;
+	int scale_post_decml;
+	int scale_precision;
+	int value_offset;
+	u64 timestamp;
+};
+
+static const u32 hinge_sensitivity_addresses[] = {
+	HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(1),
+};
+
+/* Channel definitions */
+static const struct iio_chan_spec hinge_channels[] = {
+	{
+		.type = IIO_ANGL,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type =
+			BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_SAMP_FREQ) | BIT(IIO_CHAN_INFO_HYSTERESIS),
+		.scan_index = CHANNEL_SCAN_INDEX_HINGE_ANGLE,
+		.scan_type = {
+			.sign = 's',
+			.storagebits = 32,
+		},
+	}, {
+		.type = IIO_ANGL,
+		.indexed = 1,
+		.channel = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type =
+			BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_SAMP_FREQ) | BIT(IIO_CHAN_INFO_HYSTERESIS),
+		.scan_index = CHANNEL_SCAN_INDEX_SCREEN_ANGLE,
+		.scan_type = {
+			.sign = 's',
+			.storagebits = 32,
+		},
+	}, {
+		.type = IIO_ANGL,
+		.indexed = 1,
+		.channel = 2,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type =
+			BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_SAMP_FREQ) | BIT(IIO_CHAN_INFO_HYSTERESIS),
+		.scan_index = CHANNEL_SCAN_INDEX_KEYBOARD_ANGLE,
+		.scan_type = {
+			.sign = 's',
+			.storagebits = 32,
+		},
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(CHANNEL_SCAN_INDEX_TIMESTAMP)
+};
+
+/* Adjust channel real bits based on report descriptor */
+static void hinge_adjust_channel_realbits(struct iio_chan_spec *channels,
+					  int channel, int size)
+{
+	channels[channel].scan_type.realbits = size * 8;
+}
+
+/* Channel read_raw handler */
+static int hinge_read_raw(struct iio_dev *indio_dev,
+			  struct iio_chan_spec const *chan,
+			  int *val, int *val2, long mask)
+{
+	struct hinge_state *st = iio_priv(indio_dev);
+	struct hid_sensor_hub_device *hsdev;
+	int report_id;
+	s32 min;
+
+	hsdev = st->common_attributes.hsdev;
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		hid_sensor_power_state(&st->common_attributes, true);
+		report_id = st->hinge[chan->scan_index].report_id;
+		min = st->hinge[chan->scan_index].logical_minimum;
+		if (report_id < 0) {
+			hid_sensor_power_state(&st->common_attributes, false);
+			return -EINVAL;
+		}
+
+		*val = sensor_hub_input_attr_get_raw_value(st->common_attributes.hsdev,
+							   hsdev->usage,
+							   hinge_addresses[chan->scan_index],
+							   report_id,
+							   SENSOR_HUB_SYNC, min < 0);
+
+		hid_sensor_power_state(&st->common_attributes, false);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = st->scale_pre_decml;
+		*val2 = st->scale_post_decml;
+		return st->scale_precision;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = st->value_offset;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return hid_sensor_read_samp_freq_value(&st->common_attributes,
+						       val, val2);
+	case IIO_CHAN_INFO_HYSTERESIS:
+		return hid_sensor_read_raw_hyst_value(&st->common_attributes,
+						      val, val2);
+	default:
+		return -EINVAL;
+	}
+}
+
+/* Channel write_raw handler */
+static int hinge_write_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int val, int val2, long mask)
+{
+	struct hinge_state *st = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return hid_sensor_write_samp_freq_value(&st->common_attributes,
+							val, val2);
+	case IIO_CHAN_INFO_HYSTERESIS:
+		return hid_sensor_write_raw_hyst_value(&st->common_attributes,
+						       val, val2);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int hinge_read_label(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, char *label)
+{
+	struct hinge_state *st = iio_priv(indio_dev);
+
+	return sysfs_emit(label, "%s\n", st->labels[chan->channel]);
+}
+
+static const struct iio_info hinge_info = {
+	.read_raw = hinge_read_raw,
+	.write_raw = hinge_write_raw,
+	.read_label = hinge_read_label,
+};
+
+/*
+ * Callback handler to send event after all samples are received
+ * and captured.
+ */
+static int hinge_proc_event(struct hid_sensor_hub_device *hsdev,
+			    u32 usage_id, void *priv)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(priv);
+	struct hinge_state *st = iio_priv(indio_dev);
+
+	if (atomic_read(&st->common_attributes.data_ready)) {
+		if (!st->timestamp)
+			st->timestamp = iio_get_time_ns(indio_dev);
+
+		iio_push_to_buffers_with_timestamp(indio_dev, &st->scan,
+						   st->timestamp);
+
+		st->timestamp = 0;
+	}
+	return 0;
+}
+
+/* Capture samples in local storage */
+static int hinge_capture_sample(struct hid_sensor_hub_device *hsdev,
+				u32 usage_id,
+				size_t raw_len, char *raw_data,
+				void *priv)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(priv);
+	struct hinge_state *st = iio_priv(indio_dev);
+	int offset;
+
+	switch (usage_id) {
+	case HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(1):
+	case HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(2):
+	case HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(3):
+		offset = usage_id - HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(1);
+		st->scan.hinge_val[offset] = *(u32 *)raw_data;
+		return 0;
+	case HID_USAGE_SENSOR_TIME_TIMESTAMP:
+		st->timestamp = hid_sensor_convert_timestamp(&st->common_attributes,
+							     *(int64_t *)raw_data);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+/* Parse report which is specific to an usage id */
+static int hinge_parse_report(struct platform_device *pdev,
+			      struct hid_sensor_hub_device *hsdev,
+			      struct iio_chan_spec *channels,
+			      u32 usage_id, struct hinge_state *st)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < CHANNEL_SCAN_INDEX_MAX; ++i) {
+		ret = sensor_hub_input_get_attribute_info(hsdev,
+							  HID_INPUT_REPORT,
+							  usage_id,
+							  hinge_addresses[i],
+							  &st->hinge[i]);
+		if (ret < 0)
+			return ret;
+
+		hinge_adjust_channel_realbits(channels, i, st->hinge[i].size);
+	}
+
+	st->scale_precision = hid_sensor_format_scale(HID_USAGE_SENSOR_HINGE,
+			&st->hinge[CHANNEL_SCAN_INDEX_HINGE_ANGLE],
+			&st->scale_pre_decml, &st->scale_post_decml);
+
+	return ret;
+}
+
+/* Function to initialize the processing for usage id */
+static int hid_hinge_probe(struct platform_device *pdev)
+{
+	struct hid_sensor_hub_device *hsdev = dev_get_platdata(&pdev->dev);
+	struct hinge_state *st;
+	struct iio_dev *indio_dev;
+	int ret;
+	int i;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	st = iio_priv(indio_dev);
+	st->common_attributes.hsdev = hsdev;
+	st->common_attributes.pdev = pdev;
+	st->indio_dev = indio_dev;
+	for (i = 0; i < CHANNEL_SCAN_INDEX_MAX; i++)
+		st->labels[i] = hinge_labels[i];
+
+	ret = hid_sensor_parse_common_attributes(hsdev, hsdev->usage,
+						 &st->common_attributes,
+						 hinge_sensitivity_addresses,
+						 ARRAY_SIZE(hinge_sensitivity_addresses));
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup common attributes\n");
+		return ret;
+	}
+
+	indio_dev->num_channels = ARRAY_SIZE(hinge_channels);
+	indio_dev->channels = devm_kmemdup(&pdev->dev, hinge_channels,
+					   sizeof(hinge_channels), GFP_KERNEL);
+	if (!indio_dev->channels)
+		return -ENOMEM;
+
+	ret = hinge_parse_report(pdev, hsdev,
+				 (struct iio_chan_spec *)indio_dev->channels,
+				 hsdev->usage, st);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup attributes\n");
+		return ret;
+	}
+
+	indio_dev->info = &hinge_info;
+	indio_dev->name = "hinge";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	atomic_set(&st->common_attributes.data_ready, 0);
+	ret = hid_sensor_setup_trigger(indio_dev, indio_dev->name,
+				       &st->common_attributes);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "trigger setup failed\n");
+		return ret;
+	}
+
+	st->callbacks.send_event = hinge_proc_event;
+	st->callbacks.capture_sample = hinge_capture_sample;
+	st->callbacks.pdev = pdev;
+	ret = sensor_hub_register_callback(hsdev, hsdev->usage, &st->callbacks);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "callback reg failed\n");
+		goto error_remove_trigger;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "device register failed\n");
+		goto error_remove_callback;
+	}
+
+	return ret;
+
+error_remove_callback:
+	sensor_hub_remove_callback(hsdev, hsdev->usage);
+error_remove_trigger:
+	hid_sensor_remove_trigger(indio_dev, &st->common_attributes);
+	return ret;
+}
+
+/* Function to deinitialize the processing for usage id */
+static void hid_hinge_remove(struct platform_device *pdev)
+{
+	struct hid_sensor_hub_device *hsdev = dev_get_platdata(&pdev->dev);
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct hinge_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	sensor_hub_remove_callback(hsdev, hsdev->usage);
+	hid_sensor_remove_trigger(indio_dev, &st->common_attributes);
+}
+
+static const struct platform_device_id hid_hinge_ids[] = {
+	{
+		/* Format: HID-SENSOR-INT-usage_id_in_hex_lowercase */
+		.name = "HID-SENSOR-INT-020b",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, hid_hinge_ids);
+
+static struct platform_driver hid_hinge_platform_driver = {
+	.id_table = hid_hinge_ids,
+	.driver = {
+		.name	= KBUILD_MODNAME,
+		.pm	= &hid_sensor_pm_ops,
+	},
+	.probe		= hid_hinge_probe,
+	.remove		= hid_hinge_remove,
+};
+module_platform_driver(hid_hinge_platform_driver);
+
+MODULE_DESCRIPTION("HID Sensor INTEL Hinge");
+MODULE_AUTHOR("Ye Xiang <xiang.ye@intel.com>");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("IIO_HID");
diff --git a/drivers/iio/position/iqs624-pos.c b/drivers/iio/position/iqs624-pos.c
new file mode 100644
index 000000000..8239239c6
--- /dev/null
+++ b/drivers/iio/position/iqs624-pos.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Azoteq IQS624/625 Angular Position Sensors
+ *
+ * Copyright (C) 2019 Jeff LaBundy <jeff@labundy.com>
+ */
+
+#include <linux/device.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/mfd/iqs62x.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define IQS624_POS_DEG_OUT			0x16
+
+#define IQS624_POS_SCALE1			(314159 / 180)
+#define IQS624_POS_SCALE2			100000
+
+struct iqs624_pos_private {
+	struct iqs62x_core *iqs62x;
+	struct iio_dev *indio_dev;
+	struct notifier_block notifier;
+	struct mutex lock;
+	bool angle_en;
+	u16 angle;
+};
+
+static int iqs624_pos_angle_en(struct iqs62x_core *iqs62x, bool angle_en)
+{
+	unsigned int event_mask = IQS624_HALL_UI_WHL_EVENT;
+
+	/*
+	 * The IQS625 reports angular position in the form of coarse intervals,
+	 * so only interval change events are unmasked. Conversely, the IQS624
+	 * reports angular position down to one degree of resolution, so wheel
+	 * movement events are unmasked instead.
+	 */
+	if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
+		event_mask = IQS624_HALL_UI_INT_EVENT;
+
+	return regmap_update_bits(iqs62x->regmap, IQS624_HALL_UI, event_mask,
+				  angle_en ? 0 : 0xFF);
+}
+
+static int iqs624_pos_notifier(struct notifier_block *notifier,
+			       unsigned long event_flags, void *context)
+{
+	struct iqs62x_event_data *event_data = context;
+	struct iqs624_pos_private *iqs624_pos;
+	struct iqs62x_core *iqs62x;
+	struct iio_dev *indio_dev;
+	u16 angle = event_data->ui_data;
+	s64 timestamp;
+	int ret;
+
+	iqs624_pos = container_of(notifier, struct iqs624_pos_private,
+				  notifier);
+	indio_dev = iqs624_pos->indio_dev;
+	timestamp = iio_get_time_ns(indio_dev);
+
+	iqs62x = iqs624_pos->iqs62x;
+	if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
+		angle = event_data->interval;
+
+	mutex_lock(&iqs624_pos->lock);
+
+	if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
+		ret = iqs624_pos_angle_en(iqs62x, iqs624_pos->angle_en);
+		if (ret) {
+			dev_err(indio_dev->dev.parent,
+				"Failed to re-initialize device: %d\n", ret);
+			ret = NOTIFY_BAD;
+		} else {
+			ret = NOTIFY_OK;
+		}
+	} else if (iqs624_pos->angle_en && (angle != iqs624_pos->angle)) {
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_ANGL, 0,
+						    IIO_EV_TYPE_CHANGE,
+						    IIO_EV_DIR_NONE),
+			       timestamp);
+
+		iqs624_pos->angle = angle;
+		ret = NOTIFY_OK;
+	} else {
+		ret = NOTIFY_DONE;
+	}
+
+	mutex_unlock(&iqs624_pos->lock);
+
+	return ret;
+}
+
+static void iqs624_pos_notifier_unregister(void *context)
+{
+	struct iqs624_pos_private *iqs624_pos = context;
+	struct iio_dev *indio_dev = iqs624_pos->indio_dev;
+	int ret;
+
+	ret = blocking_notifier_chain_unregister(&iqs624_pos->iqs62x->nh,
+						 &iqs624_pos->notifier);
+	if (ret)
+		dev_err(indio_dev->dev.parent,
+			"Failed to unregister notifier: %d\n", ret);
+}
+
+static int iqs624_pos_angle_get(struct iqs62x_core *iqs62x, unsigned int *val)
+{
+	int ret;
+	__le16 val_buf;
+
+	if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
+		return regmap_read(iqs62x->regmap, iqs62x->dev_desc->interval,
+				   val);
+
+	ret = regmap_raw_read(iqs62x->regmap, IQS624_POS_DEG_OUT, &val_buf,
+			      sizeof(val_buf));
+	if (ret)
+		return ret;
+
+	*val = le16_to_cpu(val_buf);
+
+	return 0;
+}
+
+static int iqs624_pos_read_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int *val, int *val2, long mask)
+{
+	struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs624_pos->iqs62x;
+	unsigned int scale = 1;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iqs624_pos_angle_get(iqs62x, val);
+		if (ret)
+			return ret;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM) {
+			ret = regmap_read(iqs62x->regmap, IQS624_INTERVAL_DIV,
+					  &scale);
+			if (ret)
+				return ret;
+		}
+
+		*val = scale * IQS624_POS_SCALE1;
+		*val2 = IQS624_POS_SCALE2;
+		return IIO_VAL_FRACTIONAL;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int iqs624_pos_read_event_config(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					enum iio_event_type type,
+					enum iio_event_direction dir)
+{
+	struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&iqs624_pos->lock);
+	ret = iqs624_pos->angle_en;
+	mutex_unlock(&iqs624_pos->lock);
+
+	return ret;
+}
+
+static int iqs624_pos_write_event_config(struct iio_dev *indio_dev,
+					 const struct iio_chan_spec *chan,
+					 enum iio_event_type type,
+					 enum iio_event_direction dir,
+					 bool state)
+{
+	struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs624_pos->iqs62x;
+	unsigned int val;
+	int ret;
+
+	mutex_lock(&iqs624_pos->lock);
+
+	ret = iqs624_pos_angle_get(iqs62x, &val);
+	if (ret)
+		goto err_mutex;
+
+	ret = iqs624_pos_angle_en(iqs62x, state);
+	if (ret)
+		goto err_mutex;
+
+	iqs624_pos->angle = val;
+	iqs624_pos->angle_en = state;
+
+err_mutex:
+	mutex_unlock(&iqs624_pos->lock);
+
+	return ret;
+}
+
+static const struct iio_info iqs624_pos_info = {
+	.read_raw = &iqs624_pos_read_raw,
+	.read_event_config = iqs624_pos_read_event_config,
+	.write_event_config = iqs624_pos_write_event_config,
+};
+
+static const struct iio_event_spec iqs624_pos_events[] = {
+	{
+		.type = IIO_EV_TYPE_CHANGE,
+		.dir = IIO_EV_DIR_NONE,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	},
+};
+
+static const struct iio_chan_spec iqs624_pos_channels[] = {
+	{
+		.type = IIO_ANGL,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.event_spec = iqs624_pos_events,
+		.num_event_specs = ARRAY_SIZE(iqs624_pos_events),
+	},
+};
+
+static int iqs624_pos_probe(struct platform_device *pdev)
+{
+	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
+	struct iqs624_pos_private *iqs624_pos;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*iqs624_pos));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	iqs624_pos = iio_priv(indio_dev);
+	iqs624_pos->iqs62x = iqs62x;
+	iqs624_pos->indio_dev = indio_dev;
+
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = iqs624_pos_channels;
+	indio_dev->num_channels = ARRAY_SIZE(iqs624_pos_channels);
+	indio_dev->name = iqs62x->dev_desc->dev_name;
+	indio_dev->info = &iqs624_pos_info;
+
+	mutex_init(&iqs624_pos->lock);
+
+	iqs624_pos->notifier.notifier_call = iqs624_pos_notifier;
+	ret = blocking_notifier_chain_register(&iqs624_pos->iqs62x->nh,
+					       &iqs624_pos->notifier);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(&pdev->dev,
+				       iqs624_pos_notifier_unregister,
+				       iqs624_pos);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static struct platform_driver iqs624_pos_platform_driver = {
+	.driver = {
+		.name = "iqs624-pos",
+	},
+	.probe = iqs624_pos_probe,
+};
+module_platform_driver(iqs624_pos_platform_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
+MODULE_DESCRIPTION("Azoteq IQS624/625 Angular Position Sensors");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:iqs624-pos");