/* number of the first GPIO */unsignedgpio_base;/* initial polarity inversion setting */uint16_tinvert;void*context;/* param to setup/teardown */int(*setup)(structi2c_client*client,unsignedgpio,unsignedngpio,void*context);int(*teardown)(structi2c_client*client,unsignedgpio,unsignedngpio,void*context);};