patch "iio: hid-sensor-rotation: Fix stale or zero output when reading raw" added to char-misc-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    iio: hid-sensor-rotation: Fix stale or zero output when reading raw

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 3ce8d099e0afc5a7da75a2007a67f67c4f5a4af1 Mon Sep 17 00:00:00 2001
From: Zhang Lixu <lixu.zhang@intel.com>
Date: Wed, 10 Jun 2026 16:29:10 +0800
Subject: iio: hid-sensor-rotation: Fix stale or zero output when reading raw
 values

When reading the raw quaternion attribute (in_rot_quaternion_raw), the
driver currently returns either all zeros (if the sensor was never enabled)
or stale data (if the sensor was previously enabled) because it reads from
the internal buffer without explicitly requesting a new sample from the
sensor.

To fix this, power up the sensor, call sensor_hub_input_attr_read_values()
to issue a synchronous GET_REPORT and receive the full quaternion data
directly into a local buffer, then decode the four components.

Fixes: fc18dddc0625 ("iio: hid-sensors: Added device rotation support")
Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/orientation/hid-sensor-rotation.c | 40 ++++++++++++++++++-
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/orientation/hid-sensor-rotation.c b/drivers/iio/orientation/hid-sensor-rotation.c
index 4a11e4555099..1c6f02374f3c 100644
--- a/drivers/iio/orientation/hid-sensor-rotation.c
+++ b/drivers/iio/orientation/hid-sensor-rotation.c
@@ -86,6 +86,13 @@ static int dev_rot_read_raw(struct iio_dev *indio_dev,
 				long mask)
 {
 	struct dev_rot_state *rot_state = iio_priv(indio_dev);
+	struct hid_sensor_hub_device *hsdev = rot_state->common_attributes.hsdev;
+	struct hid_sensor_hub_attribute_info *info = &rot_state->quaternion;
+	u32 usage_id = HID_USAGE_SENSOR_ORIENT_QUATERNION;
+	union {
+		s16 val16[4];
+		s32 val32[4];
+	} raw_buf;
 	int ret_type;
 	int i;
 
@@ -95,8 +102,37 @@ static int dev_rot_read_raw(struct iio_dev *indio_dev,
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		if (size >= 4) {
-			for (i = 0; i < 4; ++i)
-				vals[i] = rot_state->scan.sampled_vals[i];
+			if (info->size <= 0 || info->size > sizeof(raw_buf))
+				return -EINVAL;
+
+			hid_sensor_power_state(&rot_state->common_attributes, true);
+
+			ret_type = sensor_hub_input_attr_read_values(hsdev,
+								     hsdev->usage,
+								     usage_id,
+								     info->report_id,
+								     SENSOR_HUB_SYNC,
+								     info->size,
+								     (u8 *)&raw_buf);
+
+			hid_sensor_power_state(&rot_state->common_attributes, false);
+
+			if (ret_type < 0)
+				return ret_type;
+
+			switch (info->size) {
+			case sizeof(raw_buf.val16):
+				for (i = 0; i < ARRAY_SIZE(raw_buf.val16); i++)
+					vals[i] = raw_buf.val16[i];
+				break;
+			case sizeof(raw_buf.val32):
+				for (i = 0; i < ARRAY_SIZE(raw_buf.val32); i++)
+					vals[i] = raw_buf.val32[i];
+				break;
+			default:
+				return -EINVAL;
+			}
+
 			ret_type = IIO_VAL_INT_MULTIPLE;
 			*val_len =  4;
 		} else
-- 
2.55.0