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5.5 KiB

/*
* SH SPI driver
*
* Copyright (C) 2011-2012 Renesas Solutions Corp.
*
* 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; version 2 of the License.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <common.h>
#include <console.h>
#include <malloc.h>
#include <spi.h>
#include <asm/io.h>
#include "sh_spi.h"
static void sh_spi_write(unsigned long data, unsigned long *reg)
{
writel(data, reg);
}
static unsigned long sh_spi_read(unsigned long *reg)
{
return readl(reg);
}
static void sh_spi_set_bit(unsigned long val, unsigned long *reg)
{
unsigned long tmp;
tmp = sh_spi_read(reg);
tmp |= val;
sh_spi_write(tmp, reg);
}
static void sh_spi_clear_bit(unsigned long val, unsigned long *reg)
{
unsigned long tmp;
tmp = sh_spi_read(reg);
tmp &= ~val;
sh_spi_write(tmp, reg);
}
static void clear_fifo(struct sh_spi *ss)
{
sh_spi_set_bit(SH_SPI_RSTF, &ss->regs->cr2);
sh_spi_clear_bit(SH_SPI_RSTF, &ss->regs->cr2);
}
static int recvbuf_wait(struct sh_spi *ss)
{
while (sh_spi_read(&ss->regs->cr1) & SH_SPI_RBE) {
if (ctrlc())
return 1;
udelay(10);
}
return 0;
}
static int write_fifo_empty_wait(struct sh_spi *ss)
{
while (!(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBE)) {
if (ctrlc())
return 1;
udelay(10);
}
return 0;
}
void spi_init(void)
{
}
static void sh_spi_set_cs(struct sh_spi *ss, unsigned int cs)
{
unsigned long val = 0;
if (cs & 0x01)
val |= SH_SPI_SSS0;
if (cs & 0x02)
val |= SH_SPI_SSS1;
sh_spi_clear_bit(SH_SPI_SSS0 | SH_SPI_SSS1, &ss->regs->cr4);
sh_spi_set_bit(val, &ss->regs->cr4);
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct sh_spi *ss;
if (!spi_cs_is_valid(bus, cs))
return NULL;
ss = spi_alloc_slave(struct sh_spi, bus, cs);
if (!ss)
return NULL;
ss->regs = (struct sh_spi_regs *)CONFIG_SH_SPI_BASE;
/* SPI sycle stop */
sh_spi_write(0xfe, &ss->regs->cr1);
/* CR1 init */
sh_spi_write(0x00, &ss->regs->cr1);
/* CR3 init */
sh_spi_write(0x00, &ss->regs->cr3);
sh_spi_set_cs(ss, cs);
clear_fifo(ss);
/* 1/8 clock */
sh_spi_write(sh_spi_read(&ss->regs->cr2) | 0x07, &ss->regs->cr2);
udelay(10);
return &ss->slave;
}
void spi_free_slave(struct spi_slave *slave)
{
struct sh_spi *spi = to_sh_spi(slave);
free(spi);
}
int spi_claim_bus(struct spi_slave *slave)
{
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
struct sh_spi *ss = to_sh_spi(slave);
sh_spi_write(sh_spi_read(&ss->regs->cr1) &
~(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD), &ss->regs->cr1);
}
static int sh_spi_send(struct sh_spi *ss, const unsigned char *tx_data,
unsigned int len, unsigned long flags)
{
int i, cur_len, ret = 0;
int remain = (int)len;
if (len >= SH_SPI_FIFO_SIZE)
sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
while (remain > 0) {
cur_len = (remain < SH_SPI_FIFO_SIZE) ?
remain : SH_SPI_FIFO_SIZE;
for (i = 0; i < cur_len &&
!(sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) &&
!(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBF);
i++)
sh_spi_write(tx_data[i], &ss->regs->tbr_rbr);
cur_len = i;
if (sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) {
/* Abort the transaction */
flags |= SPI_XFER_END;
sh_spi_set_bit(SH_SPI_WPABRT, &ss->regs->cr4);
ret = 1;
break;
}
remain -= cur_len;
tx_data += cur_len;
if (remain > 0)
write_fifo_empty_wait(ss);
}
if (flags & SPI_XFER_END) {
sh_spi_clear_bit(SH_SPI_SSD | SH_SPI_SSDB, &ss->regs->cr1);
sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
udelay(100);
write_fifo_empty_wait(ss);
}
return ret;
}
static int sh_spi_receive(struct sh_spi *ss, unsigned char *rx_data,
unsigned int len, unsigned long flags)
{
int i;
if (len > SH_SPI_MAX_BYTE)
sh_spi_write(SH_SPI_MAX_BYTE, &ss->regs->cr3);
else
sh_spi_write(len, &ss->regs->cr3);
sh_spi_clear_bit(SH_SPI_SSD | SH_SPI_SSDB, &ss->regs->cr1);
sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
for (i = 0; i < len; i++) {
if (recvbuf_wait(ss))
return 0;
rx_data[i] = (unsigned char)sh_spi_read(&ss->regs->tbr_rbr);
}
sh_spi_write(0, &ss->regs->cr3);
return 0;
}
int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
void *din, unsigned long flags)
{
struct sh_spi *ss = to_sh_spi(slave);
const unsigned char *tx_data = dout;
unsigned char *rx_data = din;
unsigned int len = bitlen / 8;
int ret = 0;
if (flags & SPI_XFER_BEGIN)
sh_spi_write(sh_spi_read(&ss->regs->cr1) & ~SH_SPI_SSA,
&ss->regs->cr1);
if (tx_data)
ret = sh_spi_send(ss, tx_data, len, flags);
if (ret == 0 && rx_data)
ret = sh_spi_receive(ss, rx_data, len, flags);
if (flags & SPI_XFER_END) {
sh_spi_set_bit(SH_SPI_SSD, &ss->regs->cr1);
udelay(100);
sh_spi_clear_bit(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD,
&ss->regs->cr1);
clear_fifo(ss);
}
return ret;
}
int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
if (!bus && cs < SH_SPI_NUM_CS)
return 1;
else
return 0;
}
void spi_cs_activate(struct spi_slave *slave)
{
}
void spi_cs_deactivate(struct spi_slave *slave)
{
}