[PATCH 22/32] iio:pressure:mpl3115 Force alignment of buffer

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Whilst this is another case of the issue Lars reported with
an array of elements of smaller than 8 bytes being passed
to iio_push_to_buffers_with_timestamp, the solution here is
a bit different from the other cases and relies on __aligned
working on the stack (true since 4.6?)

This one is unusual.  We have to do an explicit memset each time
as we are reading 3 bytes into a potential 4 byte channel which
may sometimes be a 2 byte channel depending on what is enabled.
As such, moving the buffer to the heap in the iio_priv structure
doesn't save us much.  We can't use a nice explicit structure
on the stack either as the data channels have different storage
sizes and are all separately controlled.

Fixes: cc26ad455f57 ("iio: Add Freescale MPL3115A2 pressure / temperature sensor driver")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/pressure/mpl3115.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c
index ccdb0b70e48c..8a481dbe808c 100644
--- a/drivers/iio/pressure/mpl3115.c
+++ b/drivers/iio/pressure/mpl3115.c
@@ -144,7 +144,8 @@ static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct mpl3115_data *data = iio_priv(indio_dev);
-	u8 buffer[16]; /* 32-bit channel + 16-bit channel + padding + ts */
+	/* 32-bit channel + 16-bit channel + padding + ts */
+	u8 buffer[16] __aligned(8);
 	int ret, pos = 0;
 
 	mutex_lock(&data->lock);
-- 
2.26.2