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130 lines
3.5 KiB
130 lines
3.5 KiB
/*
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* Copyright (c) 2019, STMicroelectronics - All Rights Reserved
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#ifndef DRIVERS_SPI_MEM_H
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#define DRIVERS_SPI_MEM_H
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#include <errno.h>
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#include <stdbool.h>
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#include <stdint.h>
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#define SPI_MEM_BUSWIDTH_1_LINE 1U
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#define SPI_MEM_BUSWIDTH_2_LINE 2U
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#define SPI_MEM_BUSWIDTH_4_LINE 4U
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/*
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* enum spi_mem_data_dir - Describes the direction of a SPI memory data
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* transfer from the controller perspective.
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* @SPI_MEM_DATA_IN: data coming from the SPI memory.
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* @SPI_MEM_DATA_OUT: data sent to the SPI memory.
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*/
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enum spi_mem_data_dir {
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SPI_MEM_DATA_IN,
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SPI_MEM_DATA_OUT,
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};
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/*
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* struct spi_mem_op - Describes a SPI memory operation.
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*
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* @cmd.buswidth: Number of IO lines used to transmit the command.
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* @cmd.opcode: Operation opcode.
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* @addr.nbytes: Number of address bytes to send. Can be zero if the operation
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* does not need to send an address.
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* @addr.buswidth: Number of IO lines used to transmit the address.
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* @addr.val: Address value. This value is always sent MSB first on the bus.
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* Note that only @addr.nbytes are taken into account in this
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* address value, so users should make sure the value fits in the
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* assigned number of bytes.
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* @dummy.nbytes: Number of dummy bytes to send after an opcode or address. Can
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* be zero if the operation does not require dummy bytes.
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* @dummy.buswidth: Number of IO lines used to transmit the dummy bytes.
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* @data.buswidth: Number of IO lines used to send/receive the data.
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* @data.dir: Direction of the transfer.
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* @data.nbytes: Number of data bytes to transfer.
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* @data.buf: Input or output data buffer depending on data::dir.
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*/
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struct spi_mem_op {
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struct {
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uint8_t buswidth;
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uint8_t opcode;
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} cmd;
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struct {
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uint8_t nbytes;
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uint8_t buswidth;
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uint64_t val;
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} addr;
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struct {
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uint8_t nbytes;
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uint8_t buswidth;
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} dummy;
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struct {
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uint8_t buswidth;
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enum spi_mem_data_dir dir;
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unsigned int nbytes;
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void *buf;
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} data;
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};
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/* SPI mode flags */
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#define SPI_CPHA BIT(0) /* clock phase */
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#define SPI_CPOL BIT(1) /* clock polarity */
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#define SPI_CS_HIGH BIT(2) /* CS active high */
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#define SPI_LSB_FIRST BIT(3) /* per-word bits-on-wire */
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#define SPI_3WIRE BIT(4) /* SI/SO signals shared */
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#define SPI_PREAMBLE BIT(5) /* Skip preamble bytes */
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#define SPI_TX_DUAL BIT(6) /* transmit with 2 wires */
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#define SPI_TX_QUAD BIT(7) /* transmit with 4 wires */
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#define SPI_RX_DUAL BIT(8) /* receive with 2 wires */
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#define SPI_RX_QUAD BIT(9) /* receive with 4 wires */
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struct spi_bus_ops {
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/*
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* Claim the bus and prepare it for communication.
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*
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* @cs: The chip select.
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* Returns: 0 if the bus was claimed successfully, or a negative value
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* if it wasn't.
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*/
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int (*claim_bus)(unsigned int cs);
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/*
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* Release the SPI bus.
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*/
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void (*release_bus)(void);
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/*
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* Set transfer speed.
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*
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* @hz: The transfer speed in Hertz.
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* Returns: 0 on success, a negative error code otherwise.
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*/
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int (*set_speed)(unsigned int hz);
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/*
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* Set the SPI mode/flags.
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*
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* @mode: Requested SPI mode (SPI_... flags).
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* Returns: 0 on success, a negative error code otherwise.
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*/
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int (*set_mode)(unsigned int mode);
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/*
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* Execute a SPI memory operation.
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*
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* @op: The memory operation to execute.
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* Returns: 0 on success, a negative error code otherwise.
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*/
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int (*exec_op)(const struct spi_mem_op *op);
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};
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int spi_mem_exec_op(const struct spi_mem_op *op);
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int spi_mem_init_slave(void *fdt, int bus_node,
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const struct spi_bus_ops *ops);
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#endif /* DRIVERS_SPI_MEM_H */
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