iio: dac: ad5686: read_raw/write_raw: use guard(mutex)()

Use guarded mutex lock to facilitate code review when adding new
attributes. This will allow for early returns, avoiding error-prone
locking and unlocking in error paths. This also adds missing include
linux/cleanup.h. Gain-control support will allow the scale attribute
to be configurable.

Reviewed-by: Maxwell Doose <m32285159@gmail.com>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

0 files changed, 0 insertions, 0 deletions