u-boot/drivers/fsl_i2c.c

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/*
* Copyright 2006 Freescale Semiconductor, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* Version 2 as published by the Free Software Foundation.
*
* 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>
#ifdef CONFIG_FSL_I2C
#ifdef CONFIG_HARD_I2C
#include <command.h>
#include <i2c.h> /* Functional interface */
#include <asm/io.h>
#include <asm/fsl_i2c.h> /* HW definitions */
#define I2C_TIMEOUT (CFG_HZ / 4)
#define I2C_READ_BIT 1
#define I2C_WRITE_BIT 0
/* Initialize the bus pointer to whatever one the SPD EEPROM is on.
* Default is bus 0. This is necessary because the DDR initialization
* runs from ROM, and we can't switch buses because we can't modify
* the global variables.
*/
#ifdef CFG_SPD_BUS_NUM
static unsigned int i2c_bus_num __attribute__ ((section ("data"))) = CFG_SPD_BUS_NUM;
#else
static unsigned int i2c_bus_num __attribute__ ((section ("data"))) = 0;
#endif
static volatile struct fsl_i2c *i2c_dev[2] = {
(struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET),
#ifdef CFG_I2C2_OFFSET
(struct fsl_i2c *) (CFG_IMMR + CFG_I2C2_OFFSET)
#endif
};
void
i2c_init(int speed, int slaveadd)
{
volatile struct fsl_i2c *dev;
dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET);
writeb(0, &dev->cr); /* stop I2C controller */
udelay(5); /* let it shutdown in peace */
writeb(0x3F, &dev->fdr); /* set bus speed */
writeb(0x3F, &dev->dfsrr); /* set default filter */
writeb(slaveadd << 1, &dev->adr); /* write slave address */
writeb(0x0, &dev->sr); /* clear status register */
writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */
#ifdef CFG_I2C2_OFFSET
dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C2_OFFSET);
writeb(0, &dev->cr); /* stop I2C controller */
writeb(0x3F, &dev->fdr); /* set bus speed */
writeb(0x3F, &dev->dfsrr); /* set default filter */
writeb(slaveadd, &dev->adr); /* write slave address */
writeb(0x0, &dev->sr); /* clear status register */
writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */
#endif /* CFG_I2C2_OFFSET */
}
static __inline__ int
i2c_wait4bus(void)
{
ulong timeval = get_timer(0);
while (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB) {
if (get_timer(timeval) > I2C_TIMEOUT) {
return -1;
}
}
return 0;
}
static __inline__ int
i2c_wait(int write)
{
u32 csr;
ulong timeval = get_timer(0);
do {
csr = readb(&i2c_dev[i2c_bus_num]->sr);
if (!(csr & I2C_SR_MIF))
continue;
writeb(0x0, &i2c_dev[i2c_bus_num]->sr);
if (csr & I2C_SR_MAL) {
debug("i2c_wait: MAL\n");
return -1;
}
if (!(csr & I2C_SR_MCF)) {
debug("i2c_wait: unfinished\n");
return -1;
}
if (write == I2C_WRITE_BIT && (csr & I2C_SR_RXAK)) {
debug("i2c_wait: No RXACK\n");
return -1;
}
return 0;
} while (get_timer (timeval) < I2C_TIMEOUT);
debug("i2c_wait: timed out\n");
return -1;
}
static __inline__ int
i2c_write_addr (u8 dev, u8 dir, int rsta)
{
writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX
| (rsta ? I2C_CR_RSTA : 0),
&i2c_dev[i2c_bus_num]->cr);
writeb((dev << 1) | dir, &i2c_dev[i2c_bus_num]->dr);
if (i2c_wait(I2C_WRITE_BIT) < 0)
return 0;
return 1;
}
static __inline__ int
__i2c_write(u8 *data, int length)
{
int i;
writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
&i2c_dev[i2c_bus_num]->cr);
for (i = 0; i < length; i++) {
writeb(data[i], &i2c_dev[i2c_bus_num]->dr);
if (i2c_wait(I2C_WRITE_BIT) < 0)
break;
}
return i;
}
static __inline__ int
__i2c_read(u8 *data, int length)
{
int i;
writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0),
&i2c_dev[i2c_bus_num]->cr);
/* dummy read */
readb(&i2c_dev[i2c_bus_num]->dr);
for (i = 0; i < length; i++) {
if (i2c_wait(I2C_READ_BIT) < 0)
break;
/* Generate ack on last next to last byte */
if (i == length - 2)
writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK,
&i2c_dev[i2c_bus_num]->cr);
/* Generate stop on last byte */
if (i == length - 1)
writeb(I2C_CR_MEN | I2C_CR_TXAK, &i2c_dev[i2c_bus_num]->cr);
data[i] = readb(&i2c_dev[i2c_bus_num]->dr);
}
return i;
}
int
i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
{
int i = -1; /* signal error */
u8 *a = (u8*)&addr;
if (i2c_wait4bus() >= 0
&& i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0
&& __i2c_write(&a[4 - alen], alen) == alen)
i = 0; /* No error so far */
if (length
&& i2c_write_addr(dev, I2C_READ_BIT, 1) != 0)
i = __i2c_read(data, length);
writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr);
if (i == length)
return 0;
return -1;
}
int
i2c_write(u8 dev, uint addr, int alen, u8 *data, int length)
{
int i = -1; /* signal error */
u8 *a = (u8*)&addr;
if (i2c_wait4bus() >= 0
&& i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0
&& __i2c_write(&a[4 - alen], alen) == alen) {
i = __i2c_write(data, length);
}
writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr);
if (i == length)
return 0;
return -1;
}
int
i2c_probe(uchar chip)
{
/* For unknow reason the controller will ACK when
* probing for a slave with the same address, so skip
* it.
*/
if (chip == (readb(&i2c_dev[i2c_bus_num]->adr) >> 1))
return -1;
return i2c_read(chip, 0, 0, NULL, 0);
}
uchar
i2c_reg_read(uchar i2c_addr, uchar reg)
{
uchar buf[1];
i2c_read(i2c_addr, reg, 1, buf, 1);
return buf[0];
}
void
i2c_reg_write(uchar i2c_addr, uchar reg, uchar val)
{
i2c_write(i2c_addr, reg, 1, &val, 1);
}
int i2c_set_bus_num(unsigned int bus)
{
#ifdef CFG_I2C2_OFFSET
if (bus > 1) {
#else
if (bus > 0) {
#endif
return -1;
}
i2c_bus_num = bus;
return 0;
}
int i2c_set_bus_speed(unsigned int speed)
{
return -1;
}
unsigned int i2c_get_bus_num(void)
{
return i2c_bus_num;
}
unsigned int i2c_get_bus_speed(void)
{
return 0;
}
#endif /* CONFIG_HARD_I2C */
#endif /* CONFIG_FSL_I2C */