Temperature is stored as 16bit value in two's complement format. Current
implementation ignores the sign bit. Make it aware of the sign bit by
using sign_extend32.
Fixes: 3f6b9598b6 ("iio: temperature: Add MCP9600 thermocouple EMF converter")
Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Tested-by: Andrew Hepp <andrew.hepp@ahepp.dev>
Link: https://lore.kernel.org/r/20240424185913.1177127-1-dima.fedrau@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>