u-boot/drivers/i2c/fsl_i2c.c

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/*
* Copyright 2006,2009 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_HARD_I2C
#include <command.h>
#include <i2c.h> /* Functional interface */
#include <asm/io.h>
#include <asm/fsl_i2c.h> /* HW definitions */
/* The maximum number of microseconds we will wait until another master has
* released the bus. If not defined in the board header file, then use a
* generic value.
*/
#ifndef CONFIG_I2C_MBB_TIMEOUT
#define CONFIG_I2C_MBB_TIMEOUT 100000
#endif
/* The maximum number of microseconds we will wait for a read or write
* operation to complete. If not defined in the board header file, then use a
* generic value.
*/
#ifndef CONFIG_I2C_TIMEOUT
#define CONFIG_I2C_TIMEOUT 10000
#endif
#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.
*/
#ifndef CONFIG_SYS_SPD_BUS_NUM
#define CONFIG_SYS_SPD_BUS_NUM 0
#endif
static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = CONFIG_SYS_SPD_BUS_NUM;
#if defined(CONFIG_I2C_MUX)
static unsigned int i2c_bus_num_mux __attribute__ ((section ("data"))) = 0;
#endif
static unsigned int i2c_bus_speed[2] = {CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED};
static const struct fsl_i2c *i2c_dev[2] = {
(struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET),
#ifdef CONFIG_SYS_I2C2_OFFSET
(struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_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"
*
* ColdFire I2C frequency dividers for FDR values are different from
* PowerPC. The protocol to use the I2C module is still the same.
* A different table is defined and are based on MCF5xxx user manual.
*
*/
static const struct {
unsigned short divider;
u8 fdr;
} fsl_i2c_speed_map[] = {
#ifdef __M68K__
{20, 32}, {22, 33}, {24, 34}, {26, 35},
{28, 0}, {28, 36}, {30, 1}, {32, 37},
{34, 2}, {36, 38}, {40, 3}, {40, 39},
{44, 4}, {48, 5}, {48, 40}, {56, 6},
{56, 41}, {64, 42}, {68, 7}, {72, 43},
{80, 8}, {80, 44}, {88, 9}, {96, 41},
{104, 10}, {112, 42}, {128, 11}, {128, 43},
{144, 12}, {160, 13}, {160, 48}, {192, 14},
{192, 49}, {224, 50}, {240, 15}, {256, 51},
{288, 16}, {320, 17}, {320, 52}, {384, 18},
{384, 53}, {448, 54}, {480, 19}, {512, 55},
{576, 20}, {640, 21}, {640, 56}, {768, 22},
{768, 57}, {960, 23}, {896, 58}, {1024, 59},
{1152, 24}, {1280, 25}, {1280, 60}, {1536, 26},
{1536, 61}, {1792, 62}, {1920, 27}, {2048, 63},
{2304, 28}, {2560, 29}, {3072, 30}, {3840, 31},
{-1, 31}
#endif
};
/**
* 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);
/*
* 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.
*/
#ifdef __PPC__
u8 dfsr, fdr = 0x31; /* Default if no FDR found */
/* a, b and dfsr matches identifiers A,B and C respectively in AN2919 */
unsigned short a, b, ga, gb;
unsigned long c_div, est_div;
#ifdef CONFIG_FSL_I2C_CUSTOM_DFSR
dfsr = CONFIG_FSL_I2C_CUSTOM_DFSR;
#else
/* Condition 1: dfsr <= 50/T */
dfsr = (5 * (i2c_clk / 1000)) / 100000;
#endif
#ifdef CONFIG_FSL_I2C_CUSTOM_FDR
fdr = CONFIG_FSL_I2C_CUSTOM_FDR;
speed = i2c_clk / divider; /* Fake something */
#else
debug("Requested speed:%d, i2c_clk:%d\n", speed, i2c_clk);
if (!dfsr)
dfsr = 1;
est_div = ~0;
for (ga = 0x4, a = 10; a <= 30; ga++, a += 2) {
for (gb = 0; gb < 8; gb++) {
b = 16 << gb;
c_div = b * (a + ((3*dfsr)/b)*2);
if ((c_div > divider) && (c_div < est_div)) {
unsigned short bin_gb, bin_ga;
est_div = c_div;
bin_gb = gb << 2;
bin_ga = (ga & 0x3) | ((ga & 0x4) << 3);
fdr = bin_gb | bin_ga;
speed = i2c_clk / est_div;
debug("FDR:0x%.2x, div:%ld, ga:0x%x, gb:0x%x, "
"a:%d, b:%d, speed:%d\n",
fdr, est_div, ga, gb, a, b, speed);
/* Condition 2 not accounted for */
debug("Tr <= %d ns\n",
(b - 3 * dfsr) * 1000000 /
(i2c_clk / 1000));
}
}
if (a == 20)
a += 2;
if (a == 24)
a += 4;
}
debug("divider:%d, est_div:%ld, DFSR:%d\n", divider, est_div, dfsr);
debug("FDR:0x%.2x, speed:%d\n", fdr, speed);
#endif
writeb(dfsr, &dev->dfsrr); /* set default filter */
writeb(fdr, &dev->fdr); /* set bus speed */
#else
unsigned int i;
for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++)
if (fsl_i2c_speed_map[i].divider >= divider) {
u8 fdr;
fdr = fsl_i2c_speed_map[i].fdr;
speed = i2c_clk / fsl_i2c_speed_map[i].divider;
writeb(fdr, &dev->fdr); /* set bus speed */
break;
}
#endif
return speed;
}
void
i2c_init(int speed, int slaveadd)
{
struct fsl_i2c *dev;
unsigned int temp;
#ifdef CONFIG_SYS_I2C_INIT_BOARD
/* Call board specific i2c bus reset routine before accessing the
* environment, which might be in a chip on that bus. For details
* about this problem see doc/I2C_Edge_Conditions.
*/
i2c_init_board();
#endif
dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_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 CONFIG_SYS_I2C2_OFFSET
dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_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
#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
/* Call board specific i2c bus reset routine AFTER the bus has been
* initialized. Use either this callpoint or i2c_init_board;
* which is called before i2c_init operations.
* For details about this problem see doc/I2C_Edge_Conditions.
*/
i2c_board_late_init();
#endif
}
static int
i2c_wait4bus(void)
{
unsigned long long timeval = get_ticks();
const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
while (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB) {
if ((get_ticks() - timeval) > timeout)
return -1;
}
return 0;
}
static __inline__ int
i2c_wait(int write)
{
u32 csr;
unsigned long long timeval = get_ticks();
const unsigned long long timeout = usec2ticks(CONFIG_I2C_TIMEOUT);
do {
csr = readb(&i2c_dev[i2c_bus_num]->sr);
if (!(csr & I2C_SR_MIF))
continue;
/* Read again to allow register to stabilise */
csr = readb(&i2c_dev[i2c_bus_num]->sr);
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) < 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;
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);
/* Do not generate stop on last byte */
if (i == length - 1)
writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
&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 (i2c_wait4bus()) /* Wait until STOP */
debug("i2c_read: wait4bus timed out\n");
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 (i2c_wait4bus()) /* Wait until STOP */
debug("i2c_write: wait4bus timed out\n");
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);
}
int i2c_set_bus_num(unsigned int bus)
{
#if defined(CONFIG_I2C_MUX)
if (bus < CONFIG_SYS_MAX_I2C_BUS) {
i2c_bus_num = bus;
} else {
int ret;
ret = i2x_mux_select_mux(bus);
if (ret)
return ret;
i2c_bus_num = 0;
}
i2c_bus_num_mux = bus;
#else
#ifdef CONFIG_SYS_I2C2_OFFSET
if (bus > 1) {
#else
if (bus > 0) {
#endif
return -1;
}
i2c_bus_num = bus;
#endif
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)
{
#if defined(CONFIG_I2C_MUX)
return i2c_bus_num_mux;
#else
return i2c_bus_num;
#endif
}
unsigned int i2c_get_bus_speed(void)
{
return i2c_bus_speed[i2c_bus_num];
}
#endif /* CONFIG_HARD_I2C */