From 1ef2f51e9fe424ccecca5bb0373d71b900c2cd41 Mon Sep 17 00:00:00 2001
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Date: Sat, 1 May 2021 18:01:17 +0100
Subject: [PATCH] iio: magn: hmc5843: Fix buffer alignment in iio_push_to_buffers_with_timestamp()
Git-commit: 1ef2f51e9fe424ccecca5bb0373d71b900c2cd41
Patch-mainline: v5.14-rc1
References: git-fixes

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 uses of
iio_push_to_buffers_with_timestamp()

Fixes: 7247645f6865 ("iio: hmc5843: Move hmc5843 out of staging")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-16-jic23@kernel.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/iio/magnetometer/hmc5843.h      | 8 ++++++--
 drivers/iio/magnetometer/hmc5843_core.c | 4 ++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/magnetometer/hmc5843.h b/drivers/iio/magnetometer/hmc5843.h
index 3f6c0b662941..242f742f2643 100644
--- a/drivers/iio/magnetometer/hmc5843.h
+++ b/drivers/iio/magnetometer/hmc5843.h
@@ -33,7 +33,8 @@ enum hmc5843_ids {
  * @lock:		update and read regmap data
  * @regmap:		hardware access register maps
  * @variant:		describe chip variants
- * @buffer:		3x 16-bit channels + padding + 64-bit timestamp
+ * @scan:		buffer to pack data for passing to
+ *			iio_push_to_buffers_with_timestamp()
  */
 struct hmc5843_data {
 	struct device *dev;
@@ -41,7 +42,10 @@ struct hmc5843_data {
 	struct regmap *regmap;
 	const struct hmc5843_chip_info *variant;
 	struct iio_mount_matrix orientation;
-	__be16 buffer[8];
+	struct {
+		__be16 chans[3];
+		s64 timestamp __aligned(8);
+	} scan;
 };
 
 int hmc5843_common_probe(struct device *dev, struct regmap *regmap,
diff --git a/drivers/iio/magnetometer/hmc5843_core.c b/drivers/iio/magnetometer/hmc5843_core.c
index 780faea61d82..221563e0c18f 100644
--- a/drivers/iio/magnetometer/hmc5843_core.c
+++ b/drivers/iio/magnetometer/hmc5843_core.c
@@ -446,13 +446,13 @@ static irqreturn_t hmc5843_trigger_handler(int irq, void *p)
 	}
 
 	ret = regmap_bulk_read(data->regmap, HMC5843_DATA_OUT_MSB_REGS,
-			       data->buffer, 3 * sizeof(__be16));
+			       data->scan.chans, sizeof(data->scan.chans));
 
 	mutex_unlock(&data->lock);
 	if (ret < 0)
 		goto done;
 
-	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 					   iio_get_time_ns(indio_dev));
 
 done:
-- 
2.26.2