patch "iio: add IIO_DECLARE_QUATERNION() macro" added to char-misc-linus

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

iio: add IIO_DECLARE_QUATERNION() macro

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 56bd57e7b161f75535df91b229b0b2c64c6e5581 Mon Sep 17 00:00:00 2001
From: David Lechner <[email protected]>
Date: Sat, 28 Feb 2026 14:02:22 -0600
Subject: iio: add IIO_DECLARE_QUATERNION() macro

Add a new IIO_DECLARE_QUATERNION() macro that is used to declare the field in an IIO buffer struct that contains a quaternion vector.

Quaternions are currently the only IIO data type that uses the .repeat feature of struct iio_scan_type. This has an implicit rule that the element in the buffer must be aligned to the entire size of the repeated element. This macro will make that requirement explicit. Since this is the only user, we just call the macro IIO_DECLARE_QUATERNION() instead of something more generic.

---
 include/linux/iio/iio.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

index a9ecff191bd9..2c91b7659ce9 100644
@@ -931,6 +931,18 @@ static inline void *iio_device_get_drvdata(const struct iio_dev *indio_dev)
 #define IIO_DECLARE_DMA_BUFFER_WITH_TS(type, name, count) \
 	__IIO_DECLARE_BUFFER_WITH_TS(type, name, count) __aligned(IIO_DMA_MINALIGN)
 
+/**
+ * IIO_DECLARE_QUATERNION() - Declare a quaternion element
+ * @type: element type of the individual vectors
+ * @name: identifier name
+ *
+ * Quaternions are a vector composed of 4 elements (W, X, Y, Z). Use this macro
+ * to declare a quaternion element in a struct to ensure proper alignment in
+ * an IIO buffer.
+ */
+#define IIO_DECLARE_QUATERNION(type, name) \
+	type name[4] __aligned(sizeof(type) * 4)
+
 struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv);
 
 /* The information at the returned address is guaranteed to be cacheline aligned */

2.53.0