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/*
* Copyright (C) 2008, Guennadi Liakhovetski <lg@denx.de>
*
* 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 <malloc.h>
#include <spi.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/gpio.h>
#include <asm/arch/imx-regs.h>
#include <asm/arch/clock.h>
#ifdef CONFIG_MX27
/* i.MX27 has a completely wrong register layout and register definitions in the
* datasheet, the correct one is in the Freescale's Linux driver */
#error "i.MX27 CSPI not supported due to drastic differences in register definitions" \
"See linux mxc_spi driver from Freescale for details."
#endif
static unsigned long spi_bases[] = {
MXC_SPI_BASE_ADDRESSES
};
#define OUT MXC_GPIO_DIRECTION_OUT
#define reg_read readl
#define reg_write(a, v) writel(v, a)
struct mxc_spi_slave {
struct spi_slave slave;
unsigned long base;
u32 ctrl_reg;
#if defined(MXC_ECSPI)
u32 cfg_reg;
#endif
int gpio;
int ss_pol;
};
static inline struct mxc_spi_slave *to_mxc_spi_slave(struct spi_slave *slave)
{
return container_of(slave, struct mxc_spi_slave, slave);
}
void spi_cs_activate(struct spi_slave *slave)
{
struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
if (mxcs->gpio > 0)
gpio_set_value(mxcs->gpio, mxcs->ss_pol);
}
void spi_cs_deactivate(struct spi_slave *slave)
{
struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
if (mxcs->gpio > 0)
gpio_set_value(mxcs->gpio,
!(mxcs->ss_pol));
}
u32 get_cspi_div(u32 div)
{
int i;
for (i = 0; i < 8; i++) {
if (div <= (4 << i))
return i;
}
return i;
}
#ifdef MXC_CSPI
static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
unsigned int ctrl_reg;
u32 clk_src;
u32 div;
clk_src = mxc_get_clock(MXC_CSPI_CLK);
div = DIV_ROUND_UP(clk_src, max_hz);
div = get_cspi_div(div);
debug("clk %d Hz, div %d, real clk %d Hz\n",
max_hz, div, clk_src / (4 << div));
ctrl_reg = MXC_CSPICTRL_CHIPSELECT(cs) |
MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS) |
MXC_CSPICTRL_DATARATE(div) |
MXC_CSPICTRL_EN |
#ifdef CONFIG_MX35
MXC_CSPICTRL_SSCTL |
#endif
MXC_CSPICTRL_MODE;
if (mode & SPI_CPHA)
ctrl_reg |= MXC_CSPICTRL_PHA;
if (mode & SPI_CPOL)
ctrl_reg |= MXC_CSPICTRL_POL;
if (mode & SPI_CS_HIGH)
ctrl_reg |= MXC_CSPICTRL_SSPOL;
mxcs->ctrl_reg = ctrl_reg;
return 0;
}
#endif
#ifdef MXC_ECSPI
static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
u32 clk_src = mxc_get_clock(MXC_CSPI_CLK);
s32 pre_div = 0, post_div = 0, i, reg_ctrl, reg_config;
u32 ss_pol = 0, sclkpol = 0, sclkpha = 0;
struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;
if (max_hz == 0) {
printf("Error: desired clock is 0\n");
return -1;
}
/*
* Reset SPI and set all CSs to master mode, if toggling
* between slave and master mode we might see a glitch
* on the clock line
*/
reg_ctrl = MXC_CSPICTRL_MODE_MASK;
reg_write(&regs->ctrl, reg_ctrl);
reg_ctrl |= MXC_CSPICTRL_EN;
reg_write(&regs->ctrl, reg_ctrl);
/*
* The following computation is taken directly from Freescale's code.
*/
if (clk_src > max_hz) {
pre_div = DIV_ROUND_UP(clk_src, max_hz);
if (pre_div > 16) {
post_div = pre_div / 16;
pre_div = 15;
}
if (post_div != 0) {
for (i = 0; i < 16; i++) {
if ((1 << i) >= post_div)
break;
}
if (i == 16) {
printf("Error: no divider for the freq: %d\n",
max_hz);
return -1;
}
post_div = i;
}
}
debug("pre_div = %d, post_div=%d\n", pre_div, post_div);
reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_SELCHAN(3)) |
MXC_CSPICTRL_SELCHAN(cs);
reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_PREDIV(0x0F)) |
MXC_CSPICTRL_PREDIV(pre_div);
reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_POSTDIV(0x0F)) |
MXC_CSPICTRL_POSTDIV(post_div);
/* We need to disable SPI before changing registers */
reg_ctrl &= ~MXC_CSPICTRL_EN;
if (mode & SPI_CS_HIGH)
ss_pol = 1;
if (mode & SPI_CPOL)
sclkpol = 1;
if (mode & SPI_CPHA)
sclkpha = 1;
reg_config = reg_read(&regs->cfg);
/*
* Configuration register setup
* The MX51 supports different setup for each SS
*/
reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_SSPOL))) |
(ss_pol << (cs + MXC_CSPICON_SSPOL));
reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_POL))) |
(sclkpol << (cs + MXC_CSPICON_POL));
reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_PHA))) |
(sclkpha << (cs + MXC_CSPICON_PHA));
debug("reg_ctrl = 0x%x\n", reg_ctrl);
reg_write(&regs->ctrl, reg_ctrl);
debug("reg_config = 0x%x\n", reg_config);
reg_write(&regs->cfg, reg_config);
/* save config register and control register */
mxcs->ctrl_reg = reg_ctrl;
mxcs->cfg_reg = reg_config;
/* clear interrupt reg */
reg_write(&regs->intr, 0);
reg_write(&regs->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);
return 0;
}
#endif
int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen,
const u8 *dout, u8 *din, unsigned long flags)
{
struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
int nbytes = (bitlen + 7) / 8;
u32 data, cnt, i;
struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;
debug("%s: bitlen %d dout 0x%x din 0x%x\n",
__func__, bitlen, (u32)dout, (u32)din);
mxcs->ctrl_reg = (mxcs->ctrl_reg &
~MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS)) |
MXC_CSPICTRL_BITCOUNT(bitlen - 1);
reg_write(&regs->ctrl, mxcs->ctrl_reg | MXC_CSPICTRL_EN);
#ifdef MXC_ECSPI
reg_write(&regs->cfg, mxcs->cfg_reg);
#endif
/* Clear interrupt register */
reg_write(&regs->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);
/*
* The SPI controller works only with words,
* check if less than a word is sent.
* Access to the FIFO is only 32 bit
*/
if (bitlen % 32) {
data = 0;
cnt = (bitlen % 32) / 8;
if (dout) {
for (i = 0; i < cnt; i++) {
data = (data << 8) | (*dout++ & 0xFF);
}
}
debug("Sending SPI 0x%x\n", data);
reg_write(&regs->txdata, data);
nbytes -= cnt;
}
data = 0;
while (nbytes > 0) {
data = 0;
if (dout) {
/* Buffer is not 32-bit aligned */
if ((unsigned long)dout & 0x03) {
data = 0;
for (i = 0; i < 4; i++)
data = (data << 8) | (*dout++ & 0xFF);
} else {
data = *(u32 *)dout;
data = cpu_to_be32(data);
}
dout += 4;
}
debug("Sending SPI 0x%x\n", data);
reg_write(&regs->txdata, data);
nbytes -= 4;
}
/* FIFO is written, now starts the transfer setting the XCH bit */
reg_write(&regs->ctrl, mxcs->ctrl_reg |
MXC_CSPICTRL_EN | MXC_CSPICTRL_XCH);
/* Wait until the TC (Transfer completed) bit is set */
while ((reg_read(&regs->stat) & MXC_CSPICTRL_TC) == 0)
;
/* Transfer completed, clear any pending request */
reg_write(&regs->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);
nbytes = (bitlen + 7) / 8;
cnt = nbytes % 32;
if (bitlen % 32) {
data = reg_read(&regs->rxdata);
cnt = (bitlen % 32) / 8;
data = cpu_to_be32(data) >> ((sizeof(data) - cnt) * 8);
debug("SPI Rx unaligned: 0x%x\n", data);
if (din) {
memcpy(din, &data, cnt);
din += cnt;
}
nbytes -= cnt;
}
while (nbytes > 0) {
u32 tmp;
tmp = reg_read(&regs->rxdata);
data = cpu_to_be32(tmp);
debug("SPI Rx: 0x%x 0x%x\n", tmp, data);
cnt = min(nbytes, sizeof(data));
if (din) {
memcpy(din, &data, cnt);
din += cnt;
}
nbytes -= cnt;
}
return 0;
}
int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
void *din, unsigned long flags)
{
int n_bytes = (bitlen + 7) / 8;
int n_bits;
int ret;
u32 blk_size;
u8 *p_outbuf = (u8 *)dout;
u8 *p_inbuf = (u8 *)din;
if (!slave)
return -1;
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(slave);
while (n_bytes > 0) {
if (n_bytes < MAX_SPI_BYTES)
blk_size = n_bytes;
else
blk_size = MAX_SPI_BYTES;
n_bits = blk_size * 8;
ret = spi_xchg_single(slave, n_bits, p_outbuf, p_inbuf, 0);
if (ret)
return ret;
if (dout)
p_outbuf += blk_size;
if (din)
p_inbuf += blk_size;
n_bytes -= blk_size;
}
if (flags & SPI_XFER_END) {
spi_cs_deactivate(slave);
}
return 0;
}
void spi_init(void)
{
}
static int decode_cs(struct mxc_spi_slave *mxcs, unsigned int cs)
{
int ret;
/*
* Some SPI devices require active chip-select over multiple
* transactions, we achieve this using a GPIO. Still, the SPI
* controller has to be configured to use one of its own chipselects.
* To use this feature you have to call spi_setup_slave() with
* cs = internal_cs | (gpio << 8), and you have to use some unused
* on this SPI controller cs between 0 and 3.
*/
if (cs > 3) {
mxcs->gpio = cs >> 8;
cs &= 3;
ret = gpio_direction_output(mxcs->gpio, !(mxcs->ss_pol));
if (ret) {
printf("mxc_spi: cannot setup gpio %d\n", mxcs->gpio);
return -EINVAL;
}
} else {
mxcs->gpio = -1;
}
return cs;
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct mxc_spi_slave *mxcs;
int ret;
if (bus >= ARRAY_SIZE(spi_bases))
return NULL;
mxcs = spi_alloc_slave(struct mxc_spi_slave, bus, cs);
if (!mxcs) {
puts("mxc_spi: SPI Slave not allocated !\n");
return NULL;
}
mxcs->ss_pol = (mode & SPI_CS_HIGH) ? 1 : 0;
ret = decode_cs(mxcs, cs);
if (ret < 0) {
free(mxcs);
return NULL;
}
cs = ret;
mxcs->base = spi_bases[bus];
ret = spi_cfg_mxc(mxcs, cs, max_hz, mode);
if (ret) {
printf("mxc_spi: cannot setup SPI controller\n");
free(mxcs);
return NULL;
}
return &mxcs->slave;
}
void spi_free_slave(struct spi_slave *slave)
{
struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
free(mxcs);
}
int spi_claim_bus(struct spi_slave *slave)
{
struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;
reg_write(&regs->rxdata, 1);
udelay(1);
reg_write(&regs->ctrl, mxcs->ctrl_reg);
reg_write(&regs->period, MXC_CSPIPERIOD_32KHZ);
reg_write(&regs->intr, 0);
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
/* TODO: Shut the controller down */
}