iio: accel: kxcjk-1013: Fix buffer alignment in iio_push_to_buffers_with_timestamp()

To make code more readable, use a structure to express the channel
layout and ensure the timestamp is 8 byte aligned.

Found during an audit of all calls of this function.

Fixes: 1a4fbf6a ("iio: accel: kxcjk1013 3-axis accelerometer driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-5-jic23@kernel.org

drivers/iio/accel/kxcjk-1013.c

@@ -233,6 +233,13 @@ static const struct kx_chipset_regs kx0231025_regs = {
 	.wake_thres	= KX023_REG_ATH,
 };
 
+enum kxcjk1013_axis {
+	AXIS_X,
+	AXIS_Y,
+	AXIS_Z,
+	AXIS_MAX
+};
+
 struct kxcjk1013_data {
 	struct regulator_bulk_data regulators[2];
 	struct i2c_client *client;
@@ -240,7 +247,11 @@ struct kxcjk1013_data {
 	struct iio_trigger *motion_trig;
 	struct iio_mount_matrix orientation;
 	struct mutex mutex;
-	s16 buffer[8];
+	/* Ensure timestamp naturally aligned */
+	struct {
+		s16 chans[AXIS_MAX];
+		s64 timestamp __aligned(8);
+	} scan;
 	u8 odr_bits;
 	u8 range;
 	int wake_thres;
@@ -255,13 +266,6 @@ struct kxcjk1013_data {
 	const struct kx_chipset_regs *regs;
 };
 
-enum kxcjk1013_axis {
-	AXIS_X,
-	AXIS_Y,
-	AXIS_Z,
-	AXIS_MAX,
-};
-
 enum kxcjk1013_mode {
 	STANDBY,
 	OPERATION,
@@ -1208,12 +1212,12 @@ static irqreturn_t kxcjk1013_trigger_handler(int irq, void *p)
 	ret = i2c_smbus_read_i2c_block_data_or_emulated(data->client,
 							KXCJK1013_REG_XOUT_L,
 							AXIS_MAX * 2,
-							(u8 *)data->buffer);
+							(u8 *)data->scan.chans);
 	mutex_unlock(&data->mutex);
 	if (ret < 0)
 		goto err;
 
-	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 					   data->timestamp);
 err:
 	iio_trigger_notify_done(indio_dev->trig);