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/*
* (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>
#if defined(CONFIG_SOFT_SPI)
#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 *)CFG_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 CFG_IMMR
volatile immap_t *immr = (immap_t *)CFG_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 CFG_IMMR
volatile immap_t *immr = (immap_t *)CFG_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);
}
#endif /* CONFIG_SOFT_SPI */
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