iio: adc: ad7280a: Fix alignment for DMA safety

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1. Switch to the updated
IIO_DMA_MINALIGN definition.

Fixes: 003f1d48de52 ("staging:iio:adc:ad7280a: Split buff[2] into tx and rx parts")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-11-jic23@kernel.org

iio: Replace strtobool() with kstrtobool()

strtobool() is deprecated and just a wrapper around kstrtobool().Replace
it with kstrtobool() so the deprecated function can be removed eventually.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220409105812.2113895-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7280a: Fix wrong variable used when setting thresholds.

Name of variable change missed in refactoring patch.

Fixes: 112bf4aa4afb ("staging:iio:adc:ad7280a: Switch to standard event control")
Reported-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Link: https://lore.kernel.org/r/20220226175604.662422-1-jic23@kernel.org

iio:adc:ad7280a: Move out of staging

This is a rather unusual device (in IIO anyway). However, it has
a near to standard userspace ABI.

Note the work to move this out of staging was done against a minimal
QEMU model, which doesn't model all the features of the device.
I have no intention to upstream the QEMU model as it was developed
just to enable this driver cleanup.

https://github.com/jic23/qemu/tree/ad7280a-hacks

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Link: https://lore.kernel.org/r/20220206190328.333093-21-jic23@kernel.org