/* SPI connection.  */

#define SPI_LEN_UNSELECT -1  /* Used to simulate CS.  */
#define SPI_LEN_NODATA    0  /* Used to read data without writing.  */

#define SPI_DATA_EMPTY (1 << 31)
#define SPI_DATA_PENDING (1 << 30)

static inline int xlx_spi_valid_data(uint32_t data)
{
    return !(data & SPI_DATA_EMPTY);
}

static inline int xlx_spi_data_pending(uint32_t data)
{
    return data & SPI_DATA_PENDING;
}

typedef uint32_t (*spi_push_fn)(void *opaque, uint32_t data, int len);

struct xlx_spi_ch
{
    void *slave[32];
    spi_push_fn txrx[32];
};

struct xlx_spi_device
{
    void * (*init) (void);
    spi_push_fn txrx;
    const char * device_name;
};

static inline void xlx_spi_connect_slave(struct xlx_spi_ch *spich, int nr,
                                          void *slave, spi_push_fn f)
{
    spich->slave[nr] = slave;
    spich->txrx[nr] = f;
}

static inline
uint32_t xlx_spi_txrx(struct xlx_spi_ch *spich, int nr, uint32_t data, int len)
{
    return spich->txrx[nr](spich->slave[nr], data, len);
}