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/*
* Copyright (C) 2008 Embedded Alley Solutions Inc.
*
* (C) Copyright 2009 Freescale Semiconductor, Inc.
*
* Freescale MX28 SSP/SPI driver
*
* 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 <asm/arch/spi.h>
#define SPI_NUM_BUSES 2
#define SPI_NUM_SLAVES 3
/* Initalized in spi_init() depending on SSP port configuration */
static unsigned long ssp_bases[SPI_NUM_BUSES];
/* Set in spi_set_cfg() depending on which SSP port is being used */
static unsigned long ssp_base = SSP1_BASE;
/*
* Init SSP port: SSP1 (@bus = 0) or SSP2 (@bus == 1)
*/
static void ssp_spi_init(unsigned int bus)
{
u32 spi_div;
u32 val = 0;
if (bus >= SPI_NUM_BUSES) {
printf("SPI bus %d doesn't exist\n", bus);
return;
}
ssp_base = ssp_bases[bus];
/* Reset block */
/* Clear SFTRST */
REG_CLR(ssp_base + SSP_CTRL0, CTRL0_SFTRST);
while (REG_RD(ssp_base + SSP_CTRL0) & CTRL0_SFTRST)
;
/* Clear CLKGATE */
REG_CLR(ssp_base + SSP_CTRL0, CTRL0_CLKGATE);
/* Set SFTRST and wait until CLKGATE is set */
REG_SET(ssp_base + SSP_CTRL0, CTRL0_SFTRST);
while (!(REG_RD(ssp_base + SSP_CTRL0) & CTRL0_CLKGATE))
;
/* Clear SFTRST and CLKGATE */
REG_CLR(ssp_base + SSP_CTRL0, CTRL0_SFTRST);
REG_CLR(ssp_base + SSP_CTRL0, CTRL0_CLKGATE);
/*
* Set CLK to desired value
*/
spi_div = ((CONFIG_SSP_CLK>>1) + CONFIG_SPI_CLK - 1) / CONFIG_SPI_CLK;
val = (2 << TIMING_CLOCK_DIVIDE) | ((spi_div - 1) << TIMING_CLOCK_RATE);
REG_WR(ssp_base + SSP_TIMING, val);
/* Set transfer parameters */
/* Set SSP SPI Master mode and word length to 8 bit */
REG_WR(ssp_base + SSP_CTRL1, WORD_LENGTH8 | SSP_MODE_SPI);
/* Set BUS_WIDTH to 1 bit and XFER_COUNT to 1 byte */
REG_WR(ssp_base + SSP_CTRL0,
BUS_WIDTH_SPI1 | (0x1 << CTRL0_XFER_COUNT));
/*
* Set BLOCK_SIZE and BLOCK_COUNT to 0, so that XFER_COUNT
* reflects number of bytes to send. Disalbe other bits as
* well
*/
REG_WR(ssp_base + SSP_CMD0, 0x0);
}
/*
* Init SSP ports, must be called first and only once
*/
void spi_init(void)
{
#ifdef CONFIG_SPI_SSP1
ssp_bases[0] = SSP1_BASE;
ssp_spi_init(0);
#endif
#ifdef CONFIG_SPI_SSP2
ssp_bases[1] = SSP2_BASE;
ssp_spi_init(1);
#endif
}
void spi_set_cfg(unsigned int bus, unsigned int cs, unsigned long mode)
{
u32 clr_mask = 0;
u32 set_mask = 0;
if (bus >= SPI_NUM_BUSES || cs >= SPI_NUM_SLAVES) {
printf("SPI device %d:%d doesn't exist", bus, cs);
return;
}
if (ssp_bases[bus] == 0) {
printf("SSP port %d isn't in SPI mode\n", bus + 1);
return;
}
/* Set SSP port to use */
ssp_base = ssp_bases[bus];
/* Set phase and polarity: HW_SSP_CTRL1 */
if (mode & SPI_PHASE)
set_mask |= CTRL1_PHASE;
else
clr_mask |= CTRL1_PHASE;
if (mode & SPI_POLARITY)
set_mask |= CTRL1_POLARITY;
else
clr_mask |= CTRL1_POLARITY;
REG_SET(ssp_base + SSP_CTRL1, set_mask);
REG_CLR(ssp_base + SSP_CTRL1, clr_mask);
/* Set SSn number: HW_SSP_CTRL0 */
REG_CLR(ssp_base + SSP_CTRL0, SPI_CS_CLR_MASK);
switch (cs) {
case 0:
set_mask = SPI_CS0;
break;
case 1:
set_mask = SPI_CS1;
break;
case 2:
set_mask = SPI_CS2;
break;
}
REG_SET(ssp_base + SSP_CTRL0, set_mask);
}
/* Read single data byte */
static unsigned char spi_read(void)
{
unsigned char b = 0;
/* Set XFER_LENGTH to 1 */
REG_CLR(ssp_base + SSP_CTRL0, 0xffff);
REG_SET(ssp_base + SSP_CTRL0, 1);
/* Enable READ mode */
REG_SET(ssp_base + SSP_CTRL0, CTRL0_READ);
/* Set RUN bit */
REG_SET(ssp_base + SSP_CTRL0, CTRL0_RUN);
/* Set transfer */
REG_SET(ssp_base + SSP_CTRL0, CTRL0_DATA_XFER);
while (REG_RD(ssp_base + SSP_STATUS) & STATUS_FIFO_EMPTY)
;
/* Read data byte */
b = REG_RD(ssp_base + SSP_DATA) & 0xff;
/* Wait until RUN bit is cleared */
while (REG_RD(ssp_base + SSP_CTRL0) & CTRL0_RUN)
;
return b;
}
/* Write single data byte */
static void spi_write(unsigned char b)
{
/* Set XFER_LENGTH to 1 */
REG_CLR(ssp_base + SSP_CTRL0, 0xffff);
REG_SET(ssp_base + SSP_CTRL0, 1);
/* Enable WRITE mode */
REG_CLR(ssp_base + SSP_CTRL0, CTRL0_READ);
/* Set RUN bit */
REG_SET(ssp_base + SSP_CTRL0, CTRL0_RUN);
/* Write data byte */
REG_WR(ssp_base + SSP_DATA, b);
/* Set transfer */
REG_SET(ssp_base + SSP_CTRL0, CTRL0_DATA_XFER);
/* Wait until RUN bit is cleared */
while (REG_RD(ssp_base + SSP_CTRL0) & CTRL0_RUN)
;
}
static void spi_lock_cs(void)
{
REG_CLR(ssp_base + SSP_CTRL0, CTRL0_IGNORE_CRC);
REG_SET(ssp_base + SSP_CTRL0, CTRL0_LOCK_CS);
}
static void spi_unlock_cs(void)
{
REG_CLR(ssp_base + SSP_CTRL0, CTRL0_LOCK_CS);
REG_SET(ssp_base + SSP_CTRL0, CTRL0_IGNORE_CRC);
}
void spi_txrx(const char *dout, unsigned int tx_len, char *din,
unsigned int rx_len, unsigned long flags)
{
int i;
if (tx_len == 0 && rx_len == 0)
return;
if (flags & SPI_START)
spi_lock_cs();
for (i = 0; i < tx_len; i++) {
/* Check if it is last data byte to transfer */
if (flags & SPI_STOP && rx_len == 0 && i == tx_len - 1)
spi_unlock_cs();
spi_write(dout[i]);
}
for (i = 0; i < rx_len; i++) {
/* Check if it is last data byte to transfer */
if (flags & SPI_STOP && i == rx_len - 1)
spi_unlock_cs();
din[i] = spi_read();
}
}
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