/* * (C) Copyright 2002 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com. * * Influenced by code from: * Wolfgang Denk, DENX Software Engineering, wd@denx.de. * * See file CREDITS for list of people who contributed to this * project. * * 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <common.h> #include <spi.h> #include <malloc.h> /*----------------------------------------------------------------------- * Definitions */ #ifdef DEBUG_SPI #define PRINTD(fmt,args...) printf (fmt ,##args) #else #define PRINTD(fmt,args...) #endif struct soft_spi_slave { struct spi_slave slave; unsigned int mode; }; static inline struct soft_spi_slave *to_soft_spi(struct spi_slave *slave) { return container_of(slave, struct soft_spi_slave, slave); } /*=====================================================================*/ /* Public Functions */ /*=====================================================================*/ /*----------------------------------------------------------------------- * Initialization */ void spi_init (void) { #ifdef SPI_INIT volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; SPI_INIT; #endif } struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, unsigned int max_hz, unsigned int mode) { struct soft_spi_slave *ss; if (!spi_cs_is_valid(bus, cs)) return NULL; ss = malloc(sizeof(struct soft_spi_slave)); if (!ss) return NULL; ss->slave.bus = bus; ss->slave.cs = cs; ss->mode = mode; /* TODO: Use max_hz to limit the SCK rate */ return &ss->slave; } void spi_free_slave(struct spi_slave *slave) { struct soft_spi_slave *ss = to_soft_spi(slave); free(ss); } int spi_claim_bus(struct spi_slave *slave) { #ifdef CONFIG_SYS_IMMR volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; #endif struct soft_spi_slave *ss = to_soft_spi(slave); /* * Make sure the SPI clock is in idle state as defined for * this slave. */ if (ss->mode & SPI_CPOL) SPI_SCL(1); else SPI_SCL(0); return 0; } void spi_release_bus(struct spi_slave *slave) { /* Nothing to do */ } /*----------------------------------------------------------------------- * SPI transfer * * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks * "bitlen" bits in the SPI MISO port. That's just the way SPI works. * * The source of the outgoing bits is the "dout" parameter and the * destination of the input bits is the "din" parameter. Note that "dout" * and "din" can point to the same memory location, in which case the * input data overwrites the output data (since both are buffered by * temporary variables, this is OK). */ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, void *din, unsigned long flags) { #ifdef CONFIG_SYS_IMMR volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; #endif struct soft_spi_slave *ss = to_soft_spi(slave); uchar tmpdin = 0; uchar tmpdout = 0; const u8 *txd = dout; u8 *rxd = din; int cpol = ss->mode & SPI_CPOL; int cpha = ss->mode & SPI_CPHA; unsigned int j; PRINTD("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n", slave->bus, slave->cs, *(uint *)txd, *(uint *)rxd, bitlen); if (flags & SPI_XFER_BEGIN) spi_cs_activate(slave); for(j = 0; j < bitlen; j++) { /* * Check if it is time to work on a new byte. */ if((j % 8) == 0) { tmpdout = *txd++; if(j != 0) { *rxd++ = tmpdin; } tmpdin = 0; } if (!cpha) SPI_SCL(!cpol); SPI_SDA(tmpdout & 0x80); SPI_DELAY; if (cpha) SPI_SCL(!cpol); else SPI_SCL(cpol); tmpdin <<= 1; tmpdin |= SPI_READ; tmpdout <<= 1; SPI_DELAY; if (cpha) SPI_SCL(cpol); } /* * If the number of bits isn't a multiple of 8, shift the last * bits over to left-justify them. Then store the last byte * read in. */ if((bitlen % 8) != 0) tmpdin <<= 8 - (bitlen % 8); *rxd++ = tmpdin; if (flags & SPI_XFER_END) spi_cs_deactivate(slave); return(0); }