1 /* Copyright 2018 SiFive, Inc */
2 /* SPDX-License-Identifier: Apache-2.0 */
9 /*! @brief The configuration for a SPI transfer */
10 struct metal_spi_config {
11 /*! @brief The protocol for the SPI transfer */
18 /*! @brief The polarity of the SPI transfer, equivalent to CPOL */
19 unsigned int polarity : 1;
20 /*! @brief The phase of the SPI transfer, equivalent to CPHA */
21 unsigned int phase : 1;
22 /*! @brief The endianness of the SPI transfer */
23 unsigned int little_endian : 1;
24 /*! @brief The active state of the chip select line */
25 unsigned int cs_active_high : 1;
26 /*! @brief The chip select ID to activate for the SPI transfer */
28 /*! @brief The spi command frame number (cycles = num * frame_len) */
30 /*! @brief The spi address frame number */
31 unsigned int addr_num;
32 /*! @brief The spi dummy frame number */
33 unsigned int dummy_num;
34 /*! @brief The Dual/Quad spi mode selection.*/
42 struct metal_spi_vtable {
43 void (*init)(struct metal_spi *spi, int baud_rate);
44 int (*transfer)(struct metal_spi *spi, struct metal_spi_config *config, size_t len, char *tx_buf, char *rx_buf);
45 int (*get_baud_rate)(struct metal_spi *spi);
46 int (*set_baud_rate)(struct metal_spi *spi, int baud_rate);
49 /*! @brief A handle for a SPI device */
51 const struct metal_spi_vtable *vtable;
54 /*! @brief Get a handle for a SPI device
55 * @param device_num The index of the desired SPI device
56 * @return A handle to the SPI device, or NULL if the device does not exist*/
57 struct metal_spi *metal_spi_get_device(unsigned int device_num);
59 /*! @brief Initialize a SPI device with a certain baud rate
60 * @param spi The handle for the SPI device to initialize
61 * @param baud_rate The baud rate to set the SPI device to
63 __inline__ void metal_spi_init(struct metal_spi *spi, int baud_rate) { spi->vtable->init(spi, baud_rate); }
65 /*! @brief Perform a SPI transfer
66 * @param spi The handle for the SPI device to perform the transfer
67 * @param config The configuration for the SPI transfer.
68 * @param len The number of bytes to transfer
69 * @param tx_buf The buffer to send over the SPI bus. Must be len bytes long. If NULL, the SPI will transfer the value 0.
70 * @param rx_buf The buffer to receive data into. Must be len bytes long. If NULL, the SPI will ignore received bytes.
71 * @return 0 if the transfer succeeds
73 __inline__ int metal_spi_transfer(struct metal_spi *spi, struct metal_spi_config *config, size_t len, char *tx_buf, char *rx_buf) {
74 return spi->vtable->transfer(spi, config, len, tx_buf, rx_buf);
77 /*! @brief Get the current baud rate of the SPI device
78 * @param spi The handle for the SPI device
79 * @return The baud rate in Hz
81 __inline__ int metal_spi_get_baud_rate(struct metal_spi *spi) { return spi->vtable->get_baud_rate(spi); }
83 /*! @brief Set the current baud rate of the SPI device
84 * @param spi The handle for the SPI device
85 * @param baud_rate The desired baud rate of the SPI device
86 * @return 0 if the baud rate is successfully changed
88 __inline__ int metal_spi_set_baud_rate(struct metal_spi *spi, int baud_rate) { return spi->vtable->set_baud_rate(spi, baud_rate); }