drivers/i2c/fsl_i2c.c - platform/external/u-boot - Gitiles

 /*
  * 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)
 {
 	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)
 {
 	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 */
	/*
	* 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)
	{
	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)
	{
	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 */