drivers/i2c/fsl_i2c.c - github/trini/u-boot - Gitiles

 /*
  * 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;
 }

 unsigned int get_i2c_clock(int bus)
 {
 	if (bus)
 		return gd->i2c2_clk;	/* I2C2 clock */
 	else
 		return gd->i2c1_clk;	/* I2C1 clock */
 }

 void
 i2c_init(int speed, int slaveadd)
 {
 	const struct fsl_i2c *dev;
 	unsigned int temp;
 	int bus_num, i;

 #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
 #ifdef CONFIG_SYS_I2C2_OFFSET
 	bus_num = 2;
 #else
 	bus_num = 1;
 #endif
 	for (i = 0; i < bus_num; i++) {
 		dev = i2c_dev[i];

 		writeb(0, &dev->cr);		/* stop I2C controller */
 		udelay(5);			/* let it shutdown in peace */
 		temp = set_i2c_bus_speed(dev, get_i2c_clock(i), speed);
 		if (gd->flags & GD_FLG_RELOC)
 			i2c_bus_speed[i] = 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_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 */
	/*
	* 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 + ((3dfsr)/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;
	}

	unsigned int get_i2c_clock(int bus)
	{
	if (bus)
	return gd->i2c2_clk; /* I2C2 clock */
	else
	return gd->i2c1_clk; /* I2C1 clock */
	}

	void
	i2c_init(int speed, int slaveadd)
	{
	const struct fsl_i2c *dev;
	unsigned int temp;
	int bus_num, i;

	#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
	#ifdef CONFIG_SYS_I2C2_OFFSET
	bus_num = 2;
	#else
	bus_num = 1;
	#endif
	for (i = 0; i < bus_num; i++) {
	dev = i2c_dev[i];

	writeb(0, &dev->cr); /* stop I2C controller */
	udelay(5); /* let it shutdown in peace */
	temp = set_i2c_bus_speed(dev, get_i2c_clock(i), speed);
	if (gd->flags & GD_FLG_RELOC)
	i2c_bus_speed[i] = 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_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 */