iio: accel: mma7660: add mount-matrix support

Allow using the mount-matrix device tree property to align the
accelerometer relative to the whole device.
Signed-off-by: Val Packett <val@packett.cool>
Link: https://lore.kernel.org/r/20240527080043.2709-1-val@packett.coolSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/accel/mma7660.c

@@ -38,21 +38,6 @@
 
 static const int mma7660_nscale = 467142857;
 
-#define MMA7660_CHANNEL(reg, axis) {	\
-	.type = IIO_ACCEL,	\
-	.address = reg,	\
-	.modified = 1,	\
-	.channel2 = IIO_MOD_##axis,	\
-	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
-	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
-}
-
-static const struct iio_chan_spec mma7660_channels[] = {
-	MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
-	MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
-	MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
-};
-
 enum mma7660_mode {
 	MMA7660_MODE_STANDBY,
 	MMA7660_MODE_ACTIVE
@@ -62,6 +47,21 @@ struct mma7660_data {
 	struct i2c_client *client;
 	struct mutex lock;
 	enum mma7660_mode mode;
+	struct iio_mount_matrix orientation;
+};
+
+static const struct iio_mount_matrix *
+mma7660_get_mount_matrix(const struct iio_dev *indio_dev,
+			const struct iio_chan_spec *chan)
+{
+	struct mma7660_data *data = iio_priv(indio_dev);
+
+	return &data->orientation;
+}
+
+static const struct iio_chan_spec_ext_info mma7660_ext_info[] = {
+	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, mma7660_get_mount_matrix),
+	{ }
 };
 
 static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);
@@ -75,6 +75,22 @@ static const struct attribute_group mma7660_attribute_group = {
 	.attrs = mma7660_attributes
 };
 
+#define MMA7660_CHANNEL(reg, axis) {	\
+	.type = IIO_ACCEL,	\
+	.address = reg,	\
+	.modified = 1,	\
+	.channel2 = IIO_MOD_##axis,	\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.ext_info = mma7660_ext_info,				\
+}
+
+static const struct iio_chan_spec mma7660_channels[] = {
+	MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
+	MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
+	MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
+};
+
 static int mma7660_set_mode(struct mma7660_data *data,
 				enum mma7660_mode mode)
 {
@@ -187,6 +203,10 @@ static int mma7660_probe(struct i2c_client *client)
 	mutex_init(&data->lock);
 	data->mode = MMA7660_MODE_STANDBY;
 
+	ret = iio_read_mount_matrix(&client->dev, &data->orientation);
+	if (ret)
+		return ret;
+
 	indio_dev->info = &mma7660_info;
 	indio_dev->name = MMA7660_DRIVER_NAME;
 	indio_dev->modes = INDIO_DIRECT_MODE;