/* * (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> /* Controller-specific definitions: */ /* SPI opcodes */ #define SPI_OPCODE_WREN 0x06 #define SPI_OPCODE_FAST_READ 0x0b #define SPI_READ_FLAG 0x01 #define SPI_WRITE_FLAG 0x02 /*----------------------------------------------------------------------- * Representation of a SPI slave, i.e. what we're communicating with. * * Drivers are expected to extend this with controller-specific data. * * bus: ID of the bus that the slave is attached to. * cs: ID of the chip select connected to the slave. * rw: Read or Write flag * max_transfer_size: maximum amount of bytes which can be sent in a single * read or write transaction, usually this is a controller * property, kept in the slave structure for convenience. Zero in * this field means 'unlimited'. */ struct spi_slave { unsigned int bus; unsigned int cs; unsigned int rw; unsigned int max_transfer_size; int force_programmer_specific; struct spi_flash * (*programmer_specific_probe) (struct spi_slave *spi); }; /*----------------------------------------------------------------------- * Initialization, must be called once on start up. * */ void spi_init(void); /*----------------------------------------------------------------------- * 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. * * Returns: A spi_slave reference that can be used in subsequent SPI * calls, or NULL if one or more of the parameters are not supported. */ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs); /*----------------------------------------------------------------------- * 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(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(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(struct spi_slave *slave, const void *dout, unsigned int bytesout, void *din, unsigned int bytesin); 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(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]; } #endif /* _SPI_GENERIC_H_ */