@brief Open a gpiochip by label.
@param label Label of the gpiochip to open.
@return GPIO chip handle or NULL if the chip with given label was not found
or an error occured.
@note If the chip cannot be found but no other error occurred, errno is set
to ENOENT.
@brief Open a gpiochip by label. @param label Label of the gpiochip to open. @return GPIO chip handle or NULL if the chip with given label was not found or an error occured. @note If the chip cannot be found but no other error occurred, errno is set to ENOENT.