arch/powerpc/cpu/mpc5xxx/i2c.c - platform/external/u-boot - Gitiles

 /*
  * (C) Copyright 2003
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  *
  * See file CREDITS for list of people who contributed to this
  * project.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of
  * the License, or (at your option) any later version.
  *
  * 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>

 DECLARE_GLOBAL_DATA_PTR;

 #ifdef CONFIG_HARD_I2C

 #include <mpc5xxx.h>
 #include <i2c.h>

 #if !defined(CONFIG_I2C_MULTI_BUS)
 #if (CONFIG_SYS_I2C_MODULE == 2)
 #define I2C_BASE	MPC5XXX_I2C2
 #elif (CONFIG_SYS_I2C_MODULE == 1)
 #define I2C_BASE	MPC5XXX_I2C1
 #else
 #error CONFIG_SYS_I2C_MODULE is not properly configured
 #endif
 #else
 static unsigned int i2c_bus_num __attribute__ ((section (".data"))) =
 						CONFIG_SYS_SPD_BUS_NUM;
 static unsigned int i2c_bus_speed[2] = {CONFIG_SYS_I2C_SPEED,
 					CONFIG_SYS_I2C_SPEED};

 static const  unsigned long i2c_dev[2] = {
 	MPC5XXX_I2C1,
 	MPC5XXX_I2C2,
 };

 #define I2C_BASE	((struct mpc5xxx_i2c *)i2c_dev[i2c_bus_num])
 #endif

 #define I2C_TIMEOUT	6667
 #define I2C_RETRIES	3

 struct mpc5xxx_i2c_tap {
 	int scl2tap;
 	int tap2tap;
 };

 static int  mpc_reg_in    (volatile u32 *reg);
 static void mpc_reg_out   (volatile u32 *reg, int val, int mask);
 static int  wait_for_bb   (void);
 static int  wait_for_pin  (int *status);
 static int  do_address    (uchar chip, char rdwr_flag);
 static int  send_bytes    (uchar chip, char *buf, int len);
 static int  receive_bytes (uchar chip, char *buf, int len);
 static int  mpc_get_fdr   (int);

 static int mpc_reg_in(volatile u32 *reg)
 {
 	int ret = *reg >> 24;
 	__asm__ __volatile__ ("eieio");
 	return ret;
 }

 static void mpc_reg_out(volatile u32 *reg, int val, int mask)
 {
 	int tmp;

 	if (!mask) {
 		*reg = val << 24;
 	} else {
 		tmp = mpc_reg_in(reg);
 		*reg = ((tmp & ~mask) | (val & mask)) << 24;
 	}
 	__asm__ __volatile__ ("eieio");

 	return;
 }

 static int wait_for_bb(void)
 {
 	struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                 timeout = I2C_TIMEOUT;
 	int                 status;

 	status = mpc_reg_in(&regs->msr);

 	while (timeout-- && (status & I2C_BB)) {
 #if 1
 		volatile int temp;
 		mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 		temp = mpc_reg_in(&regs->mdr);
 		mpc_reg_out(&regs->mcr, 0, I2C_STA);
 		mpc_reg_out(&regs->mcr, 0, 0);
 		mpc_reg_out(&regs->mcr, I2C_EN, 0);
 #endif
 		udelay(15);
 		status = mpc_reg_in(&regs->msr);
 	}

 	return (status & I2C_BB);
 }

 static int wait_for_pin(int *status)
 {
 	struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                 timeout = I2C_TIMEOUT;

 	*status = mpc_reg_in(&regs->msr);

 	while (timeout-- && !(*status & I2C_IF)) {
 		udelay(15);
 		*status = mpc_reg_in(&regs->msr);
 	}

 	if (!(*status & I2C_IF)) {
 		return -1;
 	}

 	mpc_reg_out(&regs->msr, 0, I2C_IF);

 	return 0;
 }

 static int do_address(uchar chip, char rdwr_flag)
 {
 	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                 status;

 	chip <<= 1;

 	if (rdwr_flag) {
 		chip |= 1;
 	}

 	mpc_reg_out(&regs->mcr, I2C_TX, I2C_TX);
 	mpc_reg_out(&regs->mdr, chip, 0);

 	if (wait_for_pin(&status)) {
 		return -2;
 	}

 	if (status & I2C_RXAK) {
 		return -3;
 	}

 	return 0;
 }

 static int send_bytes(uchar chip, char *buf, int len)
 {
 	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                 wrcount;
 	int                 status;

 	for (wrcount = 0; wrcount < len; ++wrcount) {

 		mpc_reg_out(&regs->mdr, buf[wrcount], 0);

 		if (wait_for_pin(&status)) {
 			break;
 		}

 		if (status & I2C_RXAK) {
 			break;
 		}

 	}

 	return !(wrcount == len);
 }

 static int receive_bytes(uchar chip, char *buf, int len)
 {
 	struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                 dummy   = 1;
 	int                 rdcount = 0;
 	int                 status;
 	int                 i;

 	mpc_reg_out(&regs->mcr, 0, I2C_TX);

 	for (i = 0; i < len; ++i) {
 		buf[rdcount] = mpc_reg_in(&regs->mdr);

 		if (dummy) {
 			dummy = 0;
 		} else {
 			rdcount++;
 		}


 		if (wait_for_pin(&status)) {
 			return -4;
 		}
 	}

 	mpc_reg_out(&regs->mcr, I2C_TXAK, I2C_TXAK);
 	buf[rdcount++] = mpc_reg_in(&regs->mdr);

 	if (wait_for_pin(&status)) {
 		return -5;
 	}

 	mpc_reg_out(&regs->mcr, 0, I2C_TXAK);

 	return 0;
 }

 #if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)

 #define FDR510(x) (u8) (((x & 0x20) >> 3) | (x & 0x3))
 #define FDR432(x) (u8) ((x & 0x1C) >> 2)
 /*
  * Reset any i2c devices that may have been interrupted during a system reset.
  * Normally this would be accomplished by clocking the line until SCL and SDA
  * are released and then sending a start condtiion (From an Atmel datasheet).
  * There is no direct access to the i2c pins so instead create start commands
  * through the i2c interface.  Send a start command then delay for the SDA Hold
  * time, repeat this by disabling/enabling the bus a total of 9 times.
  */
 static void send_reset(void)
 {
 	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 	int i;
 	u32 delay;
 	u8 fdr;
 	int SDA_Tap[] = { 3, 3, 4, 4, 1, 1, 2, 2};
 	struct mpc5xxx_i2c_tap scltap[] = {
 		{4, 1},
 		{4, 2},
 		{6, 4},
 		{6, 8},
 		{14, 16},
 		{30, 32},
 		{62, 64},
 		{126, 128}
 	};

 	fdr = (u8)mpc_reg_in(&regs->mfdr);

 	delay = scltap[FDR432(fdr)].scl2tap + ((SDA_Tap[FDR510(fdr)] - 1) * \
 		scltap[FDR432(fdr)].tap2tap) + 3;

 	for (i = 0; i < 9; i++) {
 		mpc_reg_out(&regs->mcr, I2C_EN|I2C_STA|I2C_TX, I2C_INIT_MASK);
 		udelay(delay);
 		mpc_reg_out(&regs->mcr, 0, I2C_INIT_MASK);
 		udelay(delay);
 	}

 	mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
 }
 #endif /* CONFIG_SYS_I2c_INIT_MPC5XXX */

 /**************** I2C API ****************/

 void i2c_init(int speed, int saddr)
 {
 	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;

 	mpc_reg_out(&regs->mcr, 0, 0);
 	mpc_reg_out(&regs->madr, saddr << 1, 0);

 	/* Set clock
 	 */
 	mpc_reg_out(&regs->mfdr, mpc_get_fdr(speed), 0);

 	/* Enable module
 	 */
 	mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
 	mpc_reg_out(&regs->msr, 0, I2C_IF);

 #if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)
 	send_reset();
 #endif
 	return;
 }

 static int mpc_get_fdr(int speed)
 {
 	static int fdr = -1;

 	if (fdr == -1) {
 		ulong best_speed = 0;
 		ulong divider;
 		ulong ipb, scl;
 		ulong bestmatch = 0xffffffffUL;
 		int best_i = 0, best_j = 0, i, j;
 		int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8};
 		struct mpc5xxx_i2c_tap scltap[] = {
 			{4, 1},
 			{4, 2},
 			{6, 4},
 			{6, 8},
 			{14, 16},
 			{30, 32},
 			{62, 64},
 			{126, 128}
 		};

 		ipb = gd->ipb_clk;
 		for (i = 7; i >= 0; i--) {
 			for (j = 7; j >= 0; j--) {
 				scl = 2 * (scltap[j].scl2tap +
 					(SCL_Tap[i] - 1) * scltap[j].tap2tap + 2);
 				if (ipb <= speed*scl) {
 					if ((speed*scl - ipb) < bestmatch) {
 						bestmatch = speed*scl - ipb;
 						best_i = i;
 						best_j = j;
 						best_speed = ipb/scl;
 					}
 				}
 			}
 		}
 		divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
 		if (gd->flags & GD_FLG_RELOC) {
 			fdr = divider;
 		} else {
 			printf("%ld kHz, ", best_speed / 1000);
 			return divider;
 		}
 	}

 	return fdr;
 }

 int i2c_probe(uchar chip)
 {
 	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                 i;

 	for (i = 0; i < I2C_RETRIES; i++) {
 		mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);

 		if (! do_address(chip, 0)) {
 			mpc_reg_out(&regs->mcr, 0, I2C_STA);
 			udelay(500);
 			break;
 		}

 		mpc_reg_out(&regs->mcr, 0, I2C_STA);
 		udelay(500);
 	}

 	return (i == I2C_RETRIES);
 }

 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
 {
 	char                xaddr[4];
 	struct mpc5xxx_i2c * regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                  ret         = -1;

 	xaddr[0] = (addr >> 24) & 0xFF;
 	xaddr[1] = (addr >> 16) & 0xFF;
 	xaddr[2] = (addr >>  8) & 0xFF;
 	xaddr[3] =  addr	& 0xFF;

 	if (wait_for_bb()) {
 		printf("i2c_read: bus is busy\n");
 		goto Done;
 	}

 	mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 	if (do_address(chip, 0)) {
 		printf("i2c_read: failed to address chip\n");
 		goto Done;
 	}

 	if (send_bytes(chip, &xaddr[4-alen], alen)) {
 		printf("i2c_read: send_bytes failed\n");
 		goto Done;
 	}

 	mpc_reg_out(&regs->mcr, I2C_RSTA, I2C_RSTA);
 	if (do_address(chip, 1)) {
 		printf("i2c_read: failed to address chip\n");
 		goto Done;
 	}

 	if (receive_bytes(chip, (char *)buf, len)) {
 		printf("i2c_read: receive_bytes failed\n");
 		goto Done;
 	}

 	ret = 0;
 Done:
 	mpc_reg_out(&regs->mcr, 0, I2C_STA);
 	return ret;
 }

 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
 {
 	char               xaddr[4];
 	struct mpc5xxx_i2c *regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 	int                 ret         = -1;

 	xaddr[0] = (addr >> 24) & 0xFF;
 	xaddr[1] = (addr >> 16) & 0xFF;
 	xaddr[2] = (addr >>  8) & 0xFF;
 	xaddr[3] =  addr	& 0xFF;

 	if (wait_for_bb()) {
 		printf("i2c_write: bus is busy\n");
 		goto Done;
 	}

 	mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 	if (do_address(chip, 0)) {
 		printf("i2c_write: failed to address chip\n");
 		goto Done;
 	}

 	if (send_bytes(chip, &xaddr[4-alen], alen)) {
 		printf("i2c_write: send_bytes failed\n");
 		goto Done;
 	}

 	if (send_bytes(chip, (char *)buf, len)) {
 		printf("i2c_write: send_bytes failed\n");
 		goto Done;
 	}

 	ret = 0;
 Done:
 	mpc_reg_out(&regs->mcr, 0, I2C_STA);
 	return ret;
 }

 #if defined(CONFIG_I2C_MULTI_BUS)
 int i2c_set_bus_num(unsigned int bus)
 {
 	if (bus > 1)
 		return -1;

 	i2c_bus_num = bus;
 	i2c_init(i2c_bus_speed[bus], CONFIG_SYS_I2C_SLAVE);
 	return 0;
 }

 int i2c_set_bus_speed(unsigned int speed)
 {
 	i2c_init(speed, CONFIG_SYS_I2C_SLAVE);
 	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


 #endif	/* CONFIG_HARD_I2C */
	/*
	* (C) Copyright 2003
	* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
	*
	* See file CREDITS for list of people who contributed to this
	* project.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation; either version 2 of
	* the License, or (at your option) any later version.
	*
	* 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>

	DECLARE_GLOBAL_DATA_PTR;

	#ifdef CONFIG_HARD_I2C

	#include <mpc5xxx.h>
	#include <i2c.h>

	#if !defined(CONFIG_I2C_MULTI_BUS)
	#if (CONFIG_SYS_I2C_MODULE == 2)
	#define I2C_BASE MPC5XXX_I2C2
	#elif (CONFIG_SYS_I2C_MODULE == 1)
	#define I2C_BASE MPC5XXX_I2C1
	#else
	#error CONFIG_SYS_I2C_MODULE is not properly configured
	#endif
	#else
	static unsigned int i2c_bus_num __attribute__ ((section (".data"))) =
	CONFIG_SYS_SPD_BUS_NUM;
	static unsigned int i2c_bus_speed[2] = {CONFIG_SYS_I2C_SPEED,
	CONFIG_SYS_I2C_SPEED};

	static const unsigned long i2c_dev[2] = {
	MPC5XXX_I2C1,
	MPC5XXX_I2C2,
	};

	#define I2C_BASE ((struct mpc5xxx_i2c *)i2c_dev[i2c_bus_num])
	#endif

	#define I2C_TIMEOUT 6667
	#define I2C_RETRIES 3

	struct mpc5xxx_i2c_tap {
	int scl2tap;
	int tap2tap;
	};

	static int mpc_reg_in (volatile u32 *reg);
	static void mpc_reg_out (volatile u32 *reg, int val, int mask);
	static int wait_for_bb (void);
	static int wait_for_pin (int *status);
	static int do_address (uchar chip, char rdwr_flag);
	static int send_bytes (uchar chip, char *buf, int len);
	static int receive_bytes (uchar chip, char *buf, int len);
	static int mpc_get_fdr (int);

	static int mpc_reg_in(volatile u32 *reg)
	{
	int ret = *reg >> 24;
	__asm__ __volatile__ ("eieio");
	return ret;
	}

	static void mpc_reg_out(volatile u32 *reg, int val, int mask)
	{
	int tmp;

	if (!mask) {
	*reg = val << 24;
	} else {
	tmp = mpc_reg_in(reg);
	*reg = ((tmp & ~mask) \| (val & mask)) << 24;
	}
	__asm__ __volatile__ ("eieio");

	return;
	}

	static int wait_for_bb(void)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int timeout = I2C_TIMEOUT;
	int status;

	status = mpc_reg_in(&regs->msr);

	while (timeout-- && (status & I2C_BB)) {
	#if 1
	volatile int temp;
	mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
	temp = mpc_reg_in(&regs->mdr);
	mpc_reg_out(&regs->mcr, 0, I2C_STA);
	mpc_reg_out(&regs->mcr, 0, 0);
	mpc_reg_out(&regs->mcr, I2C_EN, 0);
	#endif
	udelay(15);
	status = mpc_reg_in(&regs->msr);
	}

	return (status & I2C_BB);
	}

	static int wait_for_pin(int *status)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int timeout = I2C_TIMEOUT;

	*status = mpc_reg_in(&regs->msr);

	while (timeout-- && !(*status & I2C_IF)) {
	udelay(15);
	*status = mpc_reg_in(&regs->msr);
	}

	if (!(*status & I2C_IF)) {
	return -1;
	}

	mpc_reg_out(&regs->msr, 0, I2C_IF);

	return 0;
	}

	static int do_address(uchar chip, char rdwr_flag)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int status;

	chip <<= 1;

	if (rdwr_flag) {
	chip \|= 1;
	}

	mpc_reg_out(&regs->mcr, I2C_TX, I2C_TX);
	mpc_reg_out(&regs->mdr, chip, 0);

	if (wait_for_pin(&status)) {
	return -2;
	}

	if (status & I2C_RXAK) {
	return -3;
	}

	return 0;
	}

	static int send_bytes(uchar chip, char *buf, int len)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int wrcount;
	int status;

	for (wrcount = 0; wrcount < len; ++wrcount) {

	mpc_reg_out(&regs->mdr, buf[wrcount], 0);

	if (wait_for_pin(&status)) {
	break;
	}

	if (status & I2C_RXAK) {
	break;
	}

	}

	return !(wrcount == len);
	}

	static int receive_bytes(uchar chip, char *buf, int len)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int dummy = 1;
	int rdcount = 0;
	int status;
	int i;

	mpc_reg_out(&regs->mcr, 0, I2C_TX);

	for (i = 0; i < len; ++i) {
	buf[rdcount] = mpc_reg_in(&regs->mdr);

	if (dummy) {
	dummy = 0;
	} else {
	rdcount++;
	}


	if (wait_for_pin(&status)) {
	return -4;
	}
	}

	mpc_reg_out(&regs->mcr, I2C_TXAK, I2C_TXAK);
	buf[rdcount++] = mpc_reg_in(&regs->mdr);

	if (wait_for_pin(&status)) {
	return -5;
	}

	mpc_reg_out(&regs->mcr, 0, I2C_TXAK);

	return 0;
	}

	#if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)

	#define FDR510(x) (u8) (((x & 0x20) >> 3) \| (x & 0x3))
	#define FDR432(x) (u8) ((x & 0x1C) >> 2)
	/*
	* Reset any i2c devices that may have been interrupted during a system reset.
	* Normally this would be accomplished by clocking the line until SCL and SDA
	* are released and then sending a start condtiion (From an Atmel datasheet).
	* There is no direct access to the i2c pins so instead create start commands
	* through the i2c interface. Send a start command then delay for the SDA Hold
	* time, repeat this by disabling/enabling the bus a total of 9 times.
	*/
	static void send_reset(void)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int i;
	u32 delay;
	u8 fdr;
	int SDA_Tap[] = { 3, 3, 4, 4, 1, 1, 2, 2};
	struct mpc5xxx_i2c_tap scltap[] = {
	{4, 1},
	{4, 2},
	{6, 4},
	{6, 8},
	{14, 16},
	{30, 32},
	{62, 64},
	{126, 128}
	};

	fdr = (u8)mpc_reg_in(&regs->mfdr);

	delay = scltap[FDR432(fdr)].scl2tap + ((SDA_Tap[FDR510(fdr)] - 1) * \
	scltap[FDR432(fdr)].tap2tap) + 3;

	for (i = 0; i < 9; i++) {
	mpc_reg_out(&regs->mcr, I2C_EN\|I2C_STA\|I2C_TX, I2C_INIT_MASK);
	udelay(delay);
	mpc_reg_out(&regs->mcr, 0, I2C_INIT_MASK);
	udelay(delay);
	}

	mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
	}
	#endif /* CONFIG_SYS_I2c_INIT_MPC5XXX */

	/************** I2C API **************/

	void i2c_init(int speed, int saddr)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;

	mpc_reg_out(&regs->mcr, 0, 0);
	mpc_reg_out(&regs->madr, saddr << 1, 0);

	/* Set clock
	*/
	mpc_reg_out(&regs->mfdr, mpc_get_fdr(speed), 0);

	/* Enable module
	*/
	mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
	mpc_reg_out(&regs->msr, 0, I2C_IF);

	#if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)
	send_reset();
	#endif
	return;
	}

	static int mpc_get_fdr(int speed)
	{
	static int fdr = -1;

	if (fdr == -1) {
	ulong best_speed = 0;
	ulong divider;
	ulong ipb, scl;
	ulong bestmatch = 0xffffffffUL;
	int best_i = 0, best_j = 0, i, j;
	int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8};
	struct mpc5xxx_i2c_tap scltap[] = {
	{4, 1},
	{4, 2},
	{6, 4},
	{6, 8},
	{14, 16},
	{30, 32},
	{62, 64},
	{126, 128}
	};

	ipb = gd->ipb_clk;
	for (i = 7; i >= 0; i--) {
	for (j = 7; j >= 0; j--) {
	scl = 2 * (scltap[j].scl2tap +
	(SCL_Tap[i] - 1) * scltap[j].tap2tap + 2);
	if (ipb <= speed*scl) {
	if ((speed*scl - ipb) < bestmatch) {
	bestmatch = speed*scl - ipb;
	best_i = i;
	best_j = j;
	best_speed = ipb/scl;
	}
	}
	}
	}
	divider = (best_i & 3) \| ((best_i & 4) << 3) \| (best_j << 2);
	if (gd->flags & GD_FLG_RELOC) {
	fdr = divider;
	} else {
	printf("%ld kHz, ", best_speed / 1000);
	return divider;
	}
	}

	return fdr;
	}

	int i2c_probe(uchar chip)
	{
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int i;

	for (i = 0; i < I2C_RETRIES; i++) {
	mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);

	if (! do_address(chip, 0)) {
	mpc_reg_out(&regs->mcr, 0, I2C_STA);
	udelay(500);
	break;
	}

	mpc_reg_out(&regs->mcr, 0, I2C_STA);
	udelay(500);
	}

	return (i == I2C_RETRIES);
	}

	int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
	{
	char xaddr[4];
	struct mpc5xxx_i2c * regs = (struct mpc5xxx_i2c *)I2C_BASE;
	int ret = -1;

	xaddr[0] = (addr >> 24) & 0xFF;
	xaddr[1] = (addr >> 16) & 0xFF;
	xaddr[2] = (addr >> 8) & 0xFF;
	xaddr[3] = addr & 0xFF;

	if (wait_for_bb()) {
	printf("i2c_read: bus is busy\n");
	goto Done;
	}

	mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
	if (do_address(chip, 0)) {
	printf("i2c_read: failed to address chip\n");
	goto Done;
	}

	if (send_bytes(chip, &xaddr[4-alen], alen)) {
	printf("i2c_read: send_bytes failed\n");
	goto Done;
	}

	mpc_reg_out(&regs->mcr, I2C_RSTA, I2C_RSTA);
	if (do_address(chip, 1)) {
	printf("i2c_read: failed to address chip\n");
	goto Done;
	}

	if (receive_bytes(chip, (char *)buf, len)) {
	printf("i2c_read: receive_bytes failed\n");
	goto Done;
	}

	ret = 0;
	Done:
	mpc_reg_out(&regs->mcr, 0, I2C_STA);
	return ret;
	}

	int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
	{
	char xaddr[4];
	struct mpc5xxx_i2c regs = (struct mpc5xxx_i2c )I2C_BASE;
	int ret = -1;

	xaddr[0] = (addr >> 24) & 0xFF;
	xaddr[1] = (addr >> 16) & 0xFF;
	xaddr[2] = (addr >> 8) & 0xFF;
	xaddr[3] = addr & 0xFF;

	if (wait_for_bb()) {
	printf("i2c_write: bus is busy\n");
	goto Done;
	}

	mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
	if (do_address(chip, 0)) {
	printf("i2c_write: failed to address chip\n");
	goto Done;
	}

	if (send_bytes(chip, &xaddr[4-alen], alen)) {
	printf("i2c_write: send_bytes failed\n");
	goto Done;
	}

	if (send_bytes(chip, (char *)buf, len)) {
	printf("i2c_write: send_bytes failed\n");
	goto Done;
	}

	ret = 0;
	Done:
	mpc_reg_out(&regs->mcr, 0, I2C_STA);
	return ret;
	}

	#if defined(CONFIG_I2C_MULTI_BUS)
	int i2c_set_bus_num(unsigned int bus)
	{
	if (bus > 1)
	return -1;

	i2c_bus_num = bus;
	i2c_init(i2c_bus_speed[bus], CONFIG_SYS_I2C_SLAVE);
	return 0;
	}

	int i2c_set_bus_speed(unsigned int speed)
	{
	i2c_init(speed, CONFIG_SYS_I2C_SLAVE);
	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


	#endif /* CONFIG_HARD_I2C */