u-boot/drivers/i2c/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
DECLARE_GLOBAL_DATA_PTR;
/* 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 unsigned int i2c_bus_speed[2] = {CFG_I2C_SPEED, CFG_I2C_SPEED};
static const 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
};
/* I2C speed map for a DFSR value of 1 */
/*
* Map I2C frequency dividers to FDR and DFSR values
*
* This structure is used to define the elements of a table that maps I2C
* frequency divider (I2C clock rate divided by I2C bus speed) to a value to be
* programmed into the Frequency Divider Ratio (FDR) and Digital Filter
* Sampling Rate (DFSR) registers.
*
* The actual table should be defined in the board file, and it must be called
* fsl_i2c_speed_map[].
*
* The last entry of the table must have a value of {-1, X}, where X is same
* FDR/DFSR values as the second-to-last entry. This guarantees that any
* search through the array will always find a match.
*
* The values of the divider must be in increasing numerical order, i.e.
* fsl_i2c_speed_map[x+1].divider > fsl_i2c_speed_map[x].divider.
*
* For this table, the values are based on a value of 1 for the DFSR
* register. See the application note AN2919 "Determining the I2C Frequency
* Divider Ratio for SCL"
*/
static const struct {
unsigned short divider;
u8 dfsr;
u8 fdr;
} fsl_i2c_speed_map[] = {
{160, 1, 32}, {192, 1, 33}, {224, 1, 34}, {256, 1, 35},
{288, 1, 0}, {320, 1, 1}, {352, 6, 1}, {384, 1, 2}, {416, 6, 2},
{448, 1, 38}, {480, 1, 3}, {512, 1, 39}, {544, 11, 3}, {576, 1, 4},
{608, 22, 3}, {640, 1, 5}, {672, 32, 3}, {704, 11, 5}, {736, 43, 3},
{768, 1, 6}, {800, 54, 3}, {832, 11, 6}, {896, 1, 42}, {960, 1, 7},
{1024, 1, 43}, {1088, 22, 7}, {1152, 1, 8}, {1216, 43, 7}, {1280, 1, 9},
{1408, 22, 9}, {1536, 1, 10}, {1664, 22, 10}, {1792, 1, 46},
{1920, 1, 11}, {2048, 1, 47}, {2176, 43, 11}, {2304, 1, 12},
{2560, 1, 13}, {2816, 43, 13}, {3072, 1, 14}, {3328, 43, 14},
{3584, 1, 50}, {3840, 1, 15}, {4096, 1, 51}, {4608, 1, 16},
{5120, 1, 17}, {6144, 1, 18}, {7168, 1, 54}, {7680, 1, 19},
{8192, 1, 55}, {9216, 1, 20}, {10240, 1, 21}, {12288, 1, 22},
{14336, 1, 58}, {15360, 1, 23}, {16384, 1, 59}, {18432, 1, 24},
{20480, 1, 25}, {24576, 1, 26}, {28672, 1, 62}, {30720, 1, 27},
{32768, 1, 63}, {36864, 1, 28}, {40960, 1, 29}, {49152, 1, 30},
{61440, 1, 31}, {-1, 1, 31}
};
/**
* Set the I2C bus speed for a given I2C device
*
* @param dev: the I2C device
* @i2c_clk: I2C bus clock frequency
* @speed: the desired speed of the bus
*
* The I2C device must be stopped before calling this function.
*
* The return value is the actual bus speed that is set.
*/
static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev,
unsigned int i2c_clk, unsigned int speed)
{
unsigned short divider = min(i2c_clk / speed, (unsigned short) -1);
unsigned int i;
/*
* We want to choose an FDR/DFSR that generates an I2C bus speed that
* is equal to or lower than the requested speed. That means that we
* want the first divider that is equal to or greater than the
* calculated divider.
*/
for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++)
if (fsl_i2c_speed_map[i].divider >= divider) {
u8 fdr, dfsr;
dfsr = fsl_i2c_speed_map[i].dfsr;
fdr = fsl_i2c_speed_map[i].fdr;
speed = i2c_clk / fsl_i2c_speed_map[i].divider;
writeb(fdr, &dev->fdr); /* set bus speed */
writeb(dfsr, &dev->dfsrr); /* set default filter */
break;
}
return speed;
}
void
i2c_init(int speed, int slaveadd)
{
struct fsl_i2c *dev;
unsigned int temp;
dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET);
writeb(0, &dev->cr); /* stop I2C controller */
udelay(5); /* let it shutdown in peace */
temp = set_i2c_bus_speed(dev, gd->i2c1_clk, speed);
if (gd->flags & GD_FLG_RELOC)
i2c_bus_speed[0] = temp;
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 */
udelay(5); /* let it shutdown in peace */
temp = set_i2c_bus_speed(dev, gd->i2c2_clk, speed);
if (gd->flags & GD_FLG_RELOC)
i2c_bus_speed[1] = temp;
writeb(slaveadd << 1, &dev->adr); /* write slave address */
writeb(0x0, &dev->sr); /* clear status register */
writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */
#endif
}
static __inline__ int
i2c_wait4bus(void)
{
unsigned long long timeval = get_ticks();
while (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB) {
if ((get_ticks() - timeval) > usec2ticks(I2C_TIMEOUT))
return -1;
}
return 0;
}
static __inline__ int
i2c_wait(int write)
{
u32 csr;
unsigned long long timeval = get_ticks();
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_ticks() - timeval) < usec2ticks(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)
{
unsigned int i2c_clk = (i2c_bus_num == 1) ? gd->i2c2_clk : gd->i2c1_clk;
writeb(0, &i2c_dev[i2c_bus_num]->cr); /* stop controller */
i2c_bus_speed[i2c_bus_num] =
set_i2c_bus_speed(i2c_dev[i2c_bus_num], i2c_clk, speed);
writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); /* start controller */
return 0;
}
unsigned int i2c_get_bus_num(void)
{
return i2c_bus_num;
}
unsigned int i2c_get_bus_speed(void)
{
return i2c_bus_speed[i2c_bus_num];
}
#endif /* CONFIG_HARD_I2C */
#endif /* CONFIG_FSL_I2C */