/* * (C) Copyright 2001 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #ifndef _SPI_GENERIC_H_ #define _SPI_GENERIC_H_ #include <stdint.h> #include <stddef.h> /* Controller-specific definitions: */ struct spi_ctrlr; /*----------------------------------------------------------------------- * Representation of a SPI slave, i.e. what we're communicating with. * * bus: ID of the bus that the slave is attached to. * cs: ID of the chip select connected to the slave. * ctrlr: Pointer to SPI controller structure. */ struct spi_slave { unsigned int bus; unsigned int cs; const struct spi_ctrlr *ctrlr; }; /* Representation of SPI operation status. */ enum spi_op_status { SPI_OP_NOT_EXECUTED = 0, SPI_OP_SUCCESS = 1, SPI_OP_FAILURE = 2, }; /* * Representation of a SPI operation. * * dout: Pointer to data to send. * bytesout: Count of data in bytes to send. * din: Pointer to store received data. * bytesin: Count of data in bytes to receive. */ struct spi_op { const void *dout; size_t bytesout; void *din; size_t bytesin; enum spi_op_status status; }; enum spi_clock_phase { SPI_CLOCK_PHASE_FIRST, SPI_CLOCK_PHASE_SECOND }; enum spi_wire_mode { SPI_4_WIRE_MODE, SPI_3_WIRE_MODE }; enum spi_polarity { SPI_POLARITY_LOW, SPI_POLARITY_HIGH }; struct spi_cfg { /* CLK phase - 0: Phase first, 1: Phase second */ enum spi_clock_phase clk_phase; /* CLK polarity - 0: Low, 1: High */ enum spi_polarity clk_polarity; /* CS polarity - 0: Low, 1: High */ enum spi_polarity cs_polarity; /* Wire mode - 0: 4-wire, 1: 3-wire */ enum spi_wire_mode wire_mode; /* Data bit length. */ unsigned int data_bit_length; }; /*----------------------------------------------------------------------- * Representation of a SPI contoller. * * get_config: Get configuration of SPI bus * claim_bus: Claim SPI bus and prepare for communication. * release_bus: Release SPI bus. * setup: Setup given SPI device bus. * xfer: Perform one SPI transfer operation. * xfer_vector: Vector of SPI transfer operations. */ struct spi_ctrlr { int (*get_config)(const struct spi_slave *slave, struct spi_cfg *cfg); int (*claim_bus)(const struct spi_slave *slave); void (*release_bus)(const struct spi_slave *slave); int (*setup)(const struct spi_slave *slave); int (*xfer)(const struct spi_slave *slave, const void *dout, size_t bytesout, void *din, size_t bytesin); int (*xfer_vector)(const struct spi_slave *slave, struct spi_op vectors[], size_t count); }; /*----------------------------------------------------------------------- * Structure defining mapping of SPI buses to controller. * * ctrlr: Pointer to controller structure managing the given SPI buses. * bus_start: Start bus number managed by the controller. * bus_end: End bus number manager by the controller. */ struct spi_ctrlr_buses { const struct spi_ctrlr *ctrlr; unsigned int bus_start; unsigned int bus_end; }; /* Mapping of SPI buses to controllers - should be defined by platform. */ extern const struct spi_ctrlr_buses spi_ctrlr_bus_map[]; extern const size_t spi_ctrlr_bus_map_count; /*----------------------------------------------------------------------- * Initialization, must be called once on start up. * */ void spi_init(void); /* * Get configuration of SPI bus. * * slave: Pointer to slave structure. * cfg: Pointer to SPI configuration that needs to be filled. * * Returns: * 0 on success, -1 on error */ int spi_get_config(const struct spi_slave *slave, struct spi_cfg *cfg); /*----------------------------------------------------------------------- * Set up communications parameters for a SPI slave. * * This must be called once for each slave. Note that this function * usually doesn't touch any actual hardware, it only initializes the * contents of spi_slave so that the hardware can be easily * initialized later. * * bus: Bus ID of the slave chip. * cs: Chip select ID of the slave chip on the specified bus. * slave: Pointer to slave structure that needs to be initialized. * * Returns: * 0 on success, -1 on error */ int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave); /*----------------------------------------------------------------------- * Claim the bus and prepare it for communication with a given slave. * * This must be called before doing any transfers with a SPI slave. It * will enable and initialize any SPI hardware as necessary, and make * sure that the SCK line is in the correct idle state. It is not * allowed to claim the same bus for several slaves without releasing * the bus in between. * * slave: The SPI slave * * Returns: 0 if the bus was claimed successfully, or a negative value * if it wasn't. */ int spi_claim_bus(const struct spi_slave *slave); /*----------------------------------------------------------------------- * Release the SPI bus * * This must be called once for every call to spi_claim_bus() after * all transfers have finished. It may disable any SPI hardware as * appropriate. * * slave: The SPI slave */ void spi_release_bus(const struct spi_slave *slave); /*----------------------------------------------------------------------- * SPI transfer * * spi_xfer() interface: * slave: The SPI slave which will be sending/receiving the data. * dout: Pointer to a string of bytes to send out. * bytesout: How many bytes to write. * din: Pointer to a string of bytes that will be filled in. * bytesin: How many bytes to read. * * Returns: 0 on success, not 0 on failure */ int spi_xfer(const struct spi_slave *slave, const void *dout, size_t bytesout, void *din, size_t bytesin); /*----------------------------------------------------------------------- * Vector of SPI transfer operations * * spi_xfer_vector() interface: * slave: The SPI slave which will be sending/receiving the data. * vectors: Array of SPI op structures. * count: Number of SPI op vectors. * * Returns: 0 on success, not 0 on failure */ int spi_xfer_vector(const struct spi_slave *slave, struct spi_op vectors[], size_t count); unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len); /*----------------------------------------------------------------------- * Write 8 bits, then read 8 bits. * slave: The SPI slave we're communicating with * byte: Byte to be written * * Returns: The value that was read, or a negative value on error. * * TODO: This function probably shouldn't be inlined. */ static inline int spi_w8r8(const struct spi_slave *slave, unsigned char byte) { unsigned char dout[2]; unsigned char din[2]; int ret; dout[0] = byte; dout[1] = 0; ret = spi_xfer(slave, dout, 2, din, 2); return ret < 0 ? ret : din[1]; } /* * Helper function to allow chipsets to combine two vectors if possible. It can * only handle upto 2 vectors. * * This function is provided to support command-response kind of transactions * expected by users like flash. Some special SPI flash controllers can handle * such command-response operations in a single transaction. For these special * controllers, separate command and response vectors can be combined into a * single operation. * * Two vectors are combined if first vector has a non-NULL dout and NULL din and * second vector has a non-NULL din and NULL dout. Otherwise, each vector is * operated upon one at a time. * * Returns 0 on success and non-zero on failure. */ int spi_xfer_two_vectors(const struct spi_slave *slave, struct spi_op vectors[], size_t count); #endif /* _SPI_GENERIC_H_ */