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mpc52xx_spi.c 2.8 KiB
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  • /*
     * (C) Copyright 2009
     * Frank Bodammer <frank.bodammer@gcd-solutions.de>
     * (C) Copyright 2009 Semihalf, Grzegorz Bernacki
     *
     * 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 <asm/io.h>
    #include <malloc.h>
    #include <spi.h>
    #include <mpc5xxx.h>
    
    void spi_init(void)
    {
    	struct mpc5xxx_spi *spi = (struct mpc5xxx_spi *)MPC5XXX_SPI;
    	/*
    	 * Its important to use the correct order when initializing the
    	 * registers
    	 */
    	out_8(&spi->ddr, 0x0F);	/* set all SPI pins as output */
    	out_8(&spi->pdr, 0x00);	/* set SS low */
    	/* SPI is master, SS is general purpose output */
    	out_8(&spi->cr1, SPI_CR_MSTR | SPI_CR_SPE);
    	out_8(&spi->cr2, 0x00);	/* normal operation */
    	out_8(&spi->brr, 0x77);	/* baud rate: IPB clock / 2048 */
    }
    
    struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
    				  unsigned int max_hz, unsigned int mode)
    {
    	struct spi_slave *slave;
    
    	slave = malloc(sizeof(struct spi_slave));
    	if (!slave)
    		return NULL;
    
    	slave->bus = bus;
    	slave->cs = cs;
    
    	return slave;
    }
    
    void spi_free_slave(struct spi_slave *slave)
    {
    	free(slave);
    }
    
    int spi_claim_bus(struct spi_slave *slave)
    {
    	return 0;
    }
    
    void spi_release_bus(struct spi_slave *slave)
    {
    	return;
    }
    
    int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
    	     void *din, unsigned long flags)
    {
    	struct mpc5xxx_spi *spi = (struct mpc5xxx_spi *)MPC5XXX_SPI;
    	int i, iter = bitlen >> 3;
    	const uchar *txp = dout;
    	uchar *rxp = din;
    
    	debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
    	      slave->bus, slave->cs, *(uint *) dout, *(uint *) din, bitlen);
    
    	if (flags & SPI_XFER_BEGIN)
    		setbits_8(&spi->pdr, SPI_PDR_SS);
    
    	for (i = 0; i < iter; i++) {
    		udelay(1000);
    		debug("spi_xfer: sending %x\n", txp[i]);
    		out_8(&spi->dr, txp[i]);
    		while (!(in_8(&spi->sr) & SPI_SR_SPIF)) {
    			udelay(1000);
    			if (in_8(&spi->sr) & SPI_SR_WCOL) {
    				rxp[i] = in_8(&spi->dr);
    				puts("spi_xfer: write collision\n");
    				return -1;
    			}
    		}
    		rxp[i] = in_8(&spi->dr);
    		debug("spi_xfer: received %x\n", rxp[i]);
    	}
    	if (flags & SPI_XFER_END)
    		clrbits_8(&spi->pdr, SPI_PDR_SS);
    
    	return 0;
    }