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author | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2020-09-20 14:27:40 +0300 |
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committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2020-12-03 22:40:28 +0300 |
commit | 198cf32f0503d2ad60d320b95ef6fb8243db857f (patch) | |
tree | a28558594026d7a167976ff04f5cd9c6c1afcc3b /drivers/iio/pressure/mpl3115.c | |
parent | 7b6b51234df6cd8b04fe736b0b89c25612d896b8 (diff) | |
download | linux-198cf32f0503d2ad60d320b95ef6fb8243db857f.tar.xz |
iio:pressure:mpl3115: Force alignment of buffer
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>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200920112742.170751-7-jic23@kernel.org
Diffstat (limited to 'drivers/iio/pressure/mpl3115.c')
-rw-r--r-- | drivers/iio/pressure/mpl3115.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c index ccdb0b70e48c..1eb9e7b29e05 100644 --- a/drivers/iio/pressure/mpl3115.c +++ b/drivers/iio/pressure/mpl3115.c @@ -144,7 +144,14 @@ 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 + * Note that it is possible for only one of the first 2 + * channels to be enabled. If that happens, the first element + * of the buffer may be either 16 or 32-bits. As such we cannot + * use a simple structure definition to express this data layout. + */ + u8 buffer[16] __aligned(8); int ret, pos = 0; mutex_lock(&data->lock); |