CTL_STATUS_t mcp23x17_initialize_spi(CTL_PARALLEL_BUS_t *bus, CTL_SPI_DEVICE_t *dev);
mcp23x17_initialize_spi initializes the parallel bus driver self with methods to control an MCP23S17 on the SPI bus associated with dev. The MCP23S17 is initialized to all-input mode. The parallel bus self inherits any mutex associated with the SPI bus that dev is attached to.
Once the parallel bus interface is initialized, you can use all standard parallel bus methods from the sensor API on the interface.
mcp23x17_initialize_spi returns a standard status code.
mcp23x17_initialize_spi is thread-safe if a mutex is associated with the SPI bus that dev is attached to.