drivers/i2c/mv_i2c.c - u-boot - Git at Google

 /*
  * (C) Copyright 2000
  * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
  *
  * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  * Marius Groeger <mgroeger@sysgo.de>
  *
  * (C) Copyright 2003 Pengutronix e.K.
  * Robert Schwebel <r.schwebel@pengutronix.de>
  *
  * (C) Copyright 2011 Marvell Inc.
  * Lei Wen <leiwen@marvell.com>
  *
  * SPDX-License-Identifier:	GPL-2.0+
  *
  * Back ported to the 8xx platform (from the 8260 platform) by
  * Murray.Jensen@cmst.csiro.au, 27-Jan-01.
  */

 #include <common.h>
 #include <asm/io.h>

 #ifdef CONFIG_HARD_I2C
 #include <i2c.h>
 #include "mv_i2c.h"

 #ifdef DEBUG_I2C
 #define PRINTD(x) printf x
 #else
 #define PRINTD(x)
 #endif

 /* All transfers are described by this data structure */
 struct i2c_msg {
 	u8 condition;
 	u8 acknack;
 	u8 direction;
 	u8 data;
 };

 struct mv_i2c {
 	u32 ibmr;
 	u32 pad0;
 	u32 idbr;
 	u32 pad1;
 	u32 icr;
 	u32 pad2;
 	u32 isr;
 	u32 pad3;
 	u32 isar;
 };

 static struct mv_i2c *base;
 static void i2c_board_init(struct mv_i2c *base)
 {
 #ifdef CONFIG_SYS_I2C_INIT_BOARD
 	u32 icr;
 	/*
 	 * 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.
 	 *
 	 * disable I2C controller first, otherwhise it thinks we want to
 	 * talk to the slave port...
 	 */
 	icr = readl(&base->icr);
 	writel(readl(&base->icr) & ~(ICR_SCLE | ICR_IUE), &base->icr);

 	i2c_init_board();

 	writel(icr, &base->icr);
 #endif
 }

 #ifdef CONFIG_I2C_MULTI_BUS
 static u32 i2c_regs[CONFIG_MV_I2C_NUM] = CONFIG_MV_I2C_REG;
 static unsigned int bus_initialized[CONFIG_MV_I2C_NUM];
 static unsigned int current_bus;

 int i2c_set_bus_num(unsigned int bus)
 {
 	if ((bus < 0) || (bus >= CONFIG_MV_I2C_NUM)) {
 		printf("Bad bus: %d\n", bus);
 		return -1;
 	}

 	base = (struct mv_i2c *)i2c_regs[bus];
 	current_bus = bus;

 	if (!bus_initialized[current_bus]) {
 		i2c_board_init(base);
 		bus_initialized[current_bus] = 1;
 	}

 	return 0;
 }

 unsigned int i2c_get_bus_num(void)
 {
 	return current_bus;
 }
 #endif

 /*
  * i2c_reset: - reset the host controller
  *
  */
 static void i2c_reset(void)
 {
 	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */
 	writel(readl(&base->icr) | ICR_UR, &base->icr);	  /* reset the unit */
 	udelay(100);
 	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */

 	i2c_clk_enable();

 	writel(CONFIG_SYS_I2C_SLAVE, &base->isar); /* set our slave address */
 	writel(I2C_ICR_INIT, &base->icr); /* set control reg values */
 	writel(I2C_ISR_INIT, &base->isr); /* set clear interrupt bits */
 	writel(readl(&base->icr) | ICR_IUE, &base->icr); /* enable unit */
 	udelay(100);
 }

 /*
  * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
  *	                  are set and cleared
  *
  * @return: 1 in case of success, 0 means timeout (no match within 10 ms).
  */
 static int i2c_isr_set_cleared(unsigned long set_mask,
 			       unsigned long cleared_mask)
 {
 	int timeout = 1000, isr;

 	do {
 		isr = readl(&base->isr);
 		udelay(10);
 		if (timeout-- < 0)
 			return 0;
 	} while (((isr & set_mask) != set_mask)
 		|| ((isr & cleared_mask) != 0));

 	return 1;
 }

 /*
  * i2c_transfer: - Transfer one byte over the i2c bus
  *
  * This function can tranfer a byte over the i2c bus in both directions.
  * It is used by the public API functions.
  *
  * @return:  0: transfer successful
  *          -1: message is empty
  *          -2: transmit timeout
  *          -3: ACK missing
  *          -4: receive timeout
  *          -5: illegal parameters
  *          -6: bus is busy and couldn't be aquired
  */
 int i2c_transfer(struct i2c_msg *msg)
 {
 	int ret;

 	if (!msg)
 		goto transfer_error_msg_empty;

 	switch (msg->direction) {
 	case I2C_WRITE:
 		/* check if bus is not busy */
 		if (!i2c_isr_set_cleared(0, ISR_IBB))
 			goto transfer_error_bus_busy;

 		/* start transmission */
 		writel(readl(&base->icr) & ~ICR_START, &base->icr);
 		writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
 		writel(msg->data, &base->idbr);
 		if (msg->condition == I2C_COND_START)
 			writel(readl(&base->icr) | ICR_START, &base->icr);
 		if (msg->condition == I2C_COND_STOP)
 			writel(readl(&base->icr) | ICR_STOP, &base->icr);
 		if (msg->acknack == I2C_ACKNAK_SENDNAK)
 			writel(readl(&base->icr) | ICR_ACKNAK, &base->icr);
 		if (msg->acknack == I2C_ACKNAK_SENDACK)
 			writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
 		writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
 		writel(readl(&base->icr) | ICR_TB, &base->icr);

 		/* transmit register empty? */
 		if (!i2c_isr_set_cleared(ISR_ITE, 0))
 			goto transfer_error_transmit_timeout;

 		/* clear 'transmit empty' state */
 		writel(readl(&base->isr) | ISR_ITE, &base->isr);

 		/* wait for ACK from slave */
 		if (msg->acknack == I2C_ACKNAK_WAITACK)
 			if (!i2c_isr_set_cleared(0, ISR_ACKNAK))
 				goto transfer_error_ack_missing;
 		break;

 	case I2C_READ:

 		/* check if bus is not busy */
 		if (!i2c_isr_set_cleared(0, ISR_IBB))
 			goto transfer_error_bus_busy;

 		/* start receive */
 		writel(readl(&base->icr) & ~ICR_START, &base->icr);
 		writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
 		if (msg->condition == I2C_COND_START)
 			writel(readl(&base->icr) | ICR_START, &base->icr);
 		if (msg->condition == I2C_COND_STOP)
 			writel(readl(&base->icr) | ICR_STOP, &base->icr);
 		if (msg->acknack == I2C_ACKNAK_SENDNAK)
 			writel(readl(&base->icr) | ICR_ACKNAK, &base->icr);
 		if (msg->acknack == I2C_ACKNAK_SENDACK)
 			writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
 		writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
 		writel(readl(&base->icr) | ICR_TB, &base->icr);

 		/* receive register full? */
 		if (!i2c_isr_set_cleared(ISR_IRF, 0))
 			goto transfer_error_receive_timeout;

 		msg->data = readl(&base->idbr);

 		/* clear 'receive empty' state */
 		writel(readl(&base->isr) | ISR_IRF, &base->isr);
 		break;
 	default:
 		goto transfer_error_illegal_param;
 	}

 	return 0;

 transfer_error_msg_empty:
 		PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
 		ret = -1; goto i2c_transfer_finish;

 transfer_error_transmit_timeout:
 		PRINTD(("i2c_transfer: error: transmit timeout\n"));
 		ret = -2; goto i2c_transfer_finish;

 transfer_error_ack_missing:
 		PRINTD(("i2c_transfer: error: ACK missing\n"));
 		ret = -3; goto i2c_transfer_finish;

 transfer_error_receive_timeout:
 		PRINTD(("i2c_transfer: error: receive timeout\n"));
 		ret = -4; goto i2c_transfer_finish;

 transfer_error_illegal_param:
 		PRINTD(("i2c_transfer: error: illegal parameters\n"));
 		ret = -5; goto i2c_transfer_finish;

 transfer_error_bus_busy:
 		PRINTD(("i2c_transfer: error: bus is busy\n"));
 		ret = -6; goto i2c_transfer_finish;

 i2c_transfer_finish:
 		PRINTD(("i2c_transfer: ISR: 0x%04x\n", readl(&base->isr)));
 		i2c_reset();
 		return ret;
 }

 /* ------------------------------------------------------------------------ */
 /* API Functions                                                            */
 /* ------------------------------------------------------------------------ */
 void i2c_init(int speed, int slaveaddr)
 {
 #ifdef CONFIG_I2C_MULTI_BUS
 	current_bus = 0;
 	base = (struct mv_i2c *)i2c_regs[current_bus];
 #else
 	base = (struct mv_i2c *)CONFIG_MV_I2C_REG;
 #endif

 	i2c_board_init(base);
 }

 /*
  * i2c_probe: - Test if a chip answers for a given i2c address
  *
  * @chip:	address of the chip which is searched for
  * @return:	0 if a chip was found, -1 otherwhise
  */
 int i2c_probe(uchar chip)
 {
 	struct i2c_msg msg;

 	i2c_reset();

 	msg.condition = I2C_COND_START;
 	msg.acknack   = I2C_ACKNAK_WAITACK;
 	msg.direction = I2C_WRITE;
 	msg.data      = (chip << 1) + 1;
 	if (i2c_transfer(&msg))
 		return -1;

 	msg.condition = I2C_COND_STOP;
 	msg.acknack   = I2C_ACKNAK_SENDNAK;
 	msg.direction = I2C_READ;
 	msg.data      = 0x00;
 	if (i2c_transfer(&msg))
 		return -1;

 	return 0;
 }

 /*
  * i2c_read: - Read multiple bytes from an i2c device
  *
  * The higher level routines take into account that this function is only
  * called with len < page length of the device (see configuration file)
  *
  * @chip:	address of the chip which is to be read
  * @addr:	i2c data address within the chip
  * @alen:	length of the i2c data address (1..2 bytes)
  * @buffer:	where to write the data
  * @len:	how much byte do we want to read
  * @return:	0 in case of success
  */
 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 {
 	struct i2c_msg msg;
 	u8 addr_bytes[3]; /* lowest...highest byte of data address */

 	PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
 		"len=0x%02x)\n", chip, addr, alen, len));

 	i2c_reset();

 	/* dummy chip address write */
 	PRINTD(("i2c_read: dummy chip address write\n"));
 	msg.condition = I2C_COND_START;
 	msg.acknack   = I2C_ACKNAK_WAITACK;
 	msg.direction = I2C_WRITE;
 	msg.data = (chip << 1);
 	msg.data &= 0xFE;
 	if (i2c_transfer(&msg))
 		return -1;

 	/*
 	 * send memory address bytes;
 	 * alen defines how much bytes we have to send.
 	 */
 	/*addr &= ((1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)-1); */
 	addr_bytes[0] = (u8)((addr >>  0) & 0x000000FF);
 	addr_bytes[1] = (u8)((addr >>  8) & 0x000000FF);
 	addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);

 	while (--alen >= 0) {
 		PRINTD(("i2c_read: send memory word address byte %1d\n", alen));
 		msg.condition = I2C_COND_NORMAL;
 		msg.acknack   = I2C_ACKNAK_WAITACK;
 		msg.direction = I2C_WRITE;
 		msg.data      = addr_bytes[alen];
 		if (i2c_transfer(&msg))
 			return -1;
 	}

 	/* start read sequence */
 	PRINTD(("i2c_read: start read sequence\n"));
 	msg.condition = I2C_COND_START;
 	msg.acknack   = I2C_ACKNAK_WAITACK;
 	msg.direction = I2C_WRITE;
 	msg.data      = (chip << 1);
 	msg.data     |= 0x01;
 	if (i2c_transfer(&msg))
 		return -1;

 	/* read bytes; send NACK at last byte */
 	while (len--) {
 		if (len == 0) {
 			msg.condition = I2C_COND_STOP;
 			msg.acknack   = I2C_ACKNAK_SENDNAK;
 		} else {
 			msg.condition = I2C_COND_NORMAL;
 			msg.acknack   = I2C_ACKNAK_SENDACK;
 		}

 		msg.direction = I2C_READ;
 		msg.data      = 0x00;
 		if (i2c_transfer(&msg))
 			return -1;

 		*buffer = msg.data;
 		PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",
 			(unsigned int)buffer, *buffer));
 		buffer++;
 	}

 	i2c_reset();

 	return 0;
 }

 /*
  * i2c_write: -  Write multiple bytes to an i2c device
  *
  * The higher level routines take into account that this function is only
  * called with len < page length of the device (see configuration file)
  *
  * @chip:	address of the chip which is to be written
  * @addr:	i2c data address within the chip
  * @alen:	length of the i2c data address (1..2 bytes)
  * @buffer:	where to find the data to be written
  * @len:	how much byte do we want to read
  * @return:	0 in case of success
  */
 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 {
 	struct i2c_msg msg;
 	u8 addr_bytes[3]; /* lowest...highest byte of data address */

 	PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
 		"len=0x%02x)\n", chip, addr, alen, len));

 	i2c_reset();

 	/* chip address write */
 	PRINTD(("i2c_write: chip address write\n"));
 	msg.condition = I2C_COND_START;
 	msg.acknack   = I2C_ACKNAK_WAITACK;
 	msg.direction = I2C_WRITE;
 	msg.data = (chip << 1);
 	msg.data &= 0xFE;
 	if (i2c_transfer(&msg))
 		return -1;

 	/*
 	 * send memory address bytes;
 	 * alen defines how much bytes we have to send.
 	 */
 	addr_bytes[0] = (u8)((addr >>  0) & 0x000000FF);
 	addr_bytes[1] = (u8)((addr >>  8) & 0x000000FF);
 	addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);

 	while (--alen >= 0) {
 		PRINTD(("i2c_write: send memory word address\n"));
 		msg.condition = I2C_COND_NORMAL;
 		msg.acknack   = I2C_ACKNAK_WAITACK;
 		msg.direction = I2C_WRITE;
 		msg.data      = addr_bytes[alen];
 		if (i2c_transfer(&msg))
 			return -1;
 	}

 	/* write bytes; send NACK at last byte */
 	while (len--) {
 		PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",
 			(unsigned int)buffer, *buffer));

 		if (len == 0)
 			msg.condition = I2C_COND_STOP;
 		else
 			msg.condition = I2C_COND_NORMAL;

 		msg.acknack   = I2C_ACKNAK_WAITACK;
 		msg.direction = I2C_WRITE;
 		msg.data      = *(buffer++);

 		if (i2c_transfer(&msg))
 			return -1;
 	}

 	i2c_reset();

 	return 0;
 }
 #endif	/* CONFIG_HARD_I2C */
	/*
	* (C) Copyright 2000
	* Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
	*
	* (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
	* Marius Groeger <mgroeger@sysgo.de>
	*
	* (C) Copyright 2003 Pengutronix e.K.
	* Robert Schwebel <r.schwebel@pengutronix.de>
	*
	* (C) Copyright 2011 Marvell Inc.
	* Lei Wen <leiwen@marvell.com>
	*
	* SPDX-License-Identifier: GPL-2.0+
	*
	* Back ported to the 8xx platform (from the 8260 platform) by
	* Murray.Jensen@cmst.csiro.au, 27-Jan-01.
	*/

	#include <common.h>
	#include <asm/io.h>

	#ifdef CONFIG_HARD_I2C
	#include <i2c.h>
	#include "mv_i2c.h"

	#ifdef DEBUG_I2C
	#define PRINTD(x) printf x
	#else
	#define PRINTD(x)
	#endif

	/* All transfers are described by this data structure */
	struct i2c_msg {
	u8 condition;
	u8 acknack;
	u8 direction;
	u8 data;
	};

	struct mv_i2c {
	u32 ibmr;
	u32 pad0;
	u32 idbr;
	u32 pad1;
	u32 icr;
	u32 pad2;
	u32 isr;
	u32 pad3;
	u32 isar;
	};

	static struct mv_i2c *base;
	static void i2c_board_init(struct mv_i2c *base)
	{
	#ifdef CONFIG_SYS_I2C_INIT_BOARD
	u32 icr;
	/*
	* 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.
	*
	* disable I2C controller first, otherwhise it thinks we want to
	* talk to the slave port...
	*/
	icr = readl(&base->icr);
	writel(readl(&base->icr) & ~(ICR_SCLE \| ICR_IUE), &base->icr);

	i2c_init_board();

	writel(icr, &base->icr);
	#endif
	}

	#ifdef CONFIG_I2C_MULTI_BUS
	static u32 i2c_regs[CONFIG_MV_I2C_NUM] = CONFIG_MV_I2C_REG;
	static unsigned int bus_initialized[CONFIG_MV_I2C_NUM];
	static unsigned int current_bus;

	int i2c_set_bus_num(unsigned int bus)
	{
	if ((bus < 0) \|\| (bus >= CONFIG_MV_I2C_NUM)) {
	printf("Bad bus: %d\n", bus);
	return -1;
	}

	base = (struct mv_i2c *)i2c_regs[bus];
	current_bus = bus;

	if (!bus_initialized[current_bus]) {
	i2c_board_init(base);
	bus_initialized[current_bus] = 1;
	}

	return 0;
	}

	unsigned int i2c_get_bus_num(void)
	{
	return current_bus;
	}
	#endif

	/*
	* i2c_reset: - reset the host controller
	*
	*/
	static void i2c_reset(void)
	{
	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */
	writel(readl(&base->icr) \| ICR_UR, &base->icr); /* reset the unit */
	udelay(100);
	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */

	i2c_clk_enable();

	writel(CONFIG_SYS_I2C_SLAVE, &base->isar); /* set our slave address */
	writel(I2C_ICR_INIT, &base->icr); /* set control reg values */
	writel(I2C_ISR_INIT, &base->isr); /* set clear interrupt bits */
	writel(readl(&base->icr) \| ICR_IUE, &base->icr); /* enable unit */
	udelay(100);
	}

	/*
	* i2c_isr_set_cleared: - wait until certain bits of the I2C status register
	* are set and cleared
	*
	* @return: 1 in case of success, 0 means timeout (no match within 10 ms).
	*/
	static int i2c_isr_set_cleared(unsigned long set_mask,
	unsigned long cleared_mask)
	{
	int timeout = 1000, isr;

	do {
	isr = readl(&base->isr);
	udelay(10);
	if (timeout-- < 0)
	return 0;
	} while (((isr & set_mask) != set_mask)
	\|\| ((isr & cleared_mask) != 0));

	return 1;
	}

	/*
	* i2c_transfer: - Transfer one byte over the i2c bus
	*
	* This function can tranfer a byte over the i2c bus in both directions.
	* It is used by the public API functions.
	*
	* @return: 0: transfer successful
	* -1: message is empty
	* -2: transmit timeout
	* -3: ACK missing
	* -4: receive timeout
	* -5: illegal parameters
	* -6: bus is busy and couldn't be aquired
	*/
	int i2c_transfer(struct i2c_msg *msg)
	{
	int ret;

	if (!msg)
	goto transfer_error_msg_empty;

	switch (msg->direction) {
	case I2C_WRITE:
	/* check if bus is not busy */
	if (!i2c_isr_set_cleared(0, ISR_IBB))
	goto transfer_error_bus_busy;

	/* start transmission */
	writel(readl(&base->icr) & ~ICR_START, &base->icr);
	writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
	writel(msg->data, &base->idbr);
	if (msg->condition == I2C_COND_START)
	writel(readl(&base->icr) \| ICR_START, &base->icr);
	if (msg->condition == I2C_COND_STOP)
	writel(readl(&base->icr) \| ICR_STOP, &base->icr);
	if (msg->acknack == I2C_ACKNAK_SENDNAK)
	writel(readl(&base->icr) \| ICR_ACKNAK, &base->icr);
	if (msg->acknack == I2C_ACKNAK_SENDACK)
	writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
	writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
	writel(readl(&base->icr) \| ICR_TB, &base->icr);

	/* transmit register empty? */
	if (!i2c_isr_set_cleared(ISR_ITE, 0))
	goto transfer_error_transmit_timeout;

	/* clear 'transmit empty' state */
	writel(readl(&base->isr) \| ISR_ITE, &base->isr);

	/* wait for ACK from slave */
	if (msg->acknack == I2C_ACKNAK_WAITACK)
	if (!i2c_isr_set_cleared(0, ISR_ACKNAK))
	goto transfer_error_ack_missing;
	break;

	case I2C_READ:

	/* check if bus is not busy */
	if (!i2c_isr_set_cleared(0, ISR_IBB))
	goto transfer_error_bus_busy;

	/* start receive */
	writel(readl(&base->icr) & ~ICR_START, &base->icr);
	writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
	if (msg->condition == I2C_COND_START)
	writel(readl(&base->icr) \| ICR_START, &base->icr);
	if (msg->condition == I2C_COND_STOP)
	writel(readl(&base->icr) \| ICR_STOP, &base->icr);
	if (msg->acknack == I2C_ACKNAK_SENDNAK)
	writel(readl(&base->icr) \| ICR_ACKNAK, &base->icr);
	if (msg->acknack == I2C_ACKNAK_SENDACK)
	writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
	writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
	writel(readl(&base->icr) \| ICR_TB, &base->icr);

	/* receive register full? */
	if (!i2c_isr_set_cleared(ISR_IRF, 0))
	goto transfer_error_receive_timeout;

	msg->data = readl(&base->idbr);

	/* clear 'receive empty' state */
	writel(readl(&base->isr) \| ISR_IRF, &base->isr);
	break;
	default:
	goto transfer_error_illegal_param;
	}

	return 0;

	transfer_error_msg_empty:
	PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
	ret = -1; goto i2c_transfer_finish;

	transfer_error_transmit_timeout:
	PRINTD(("i2c_transfer: error: transmit timeout\n"));
	ret = -2; goto i2c_transfer_finish;

	transfer_error_ack_missing:
	PRINTD(("i2c_transfer: error: ACK missing\n"));
	ret = -3; goto i2c_transfer_finish;

	transfer_error_receive_timeout:
	PRINTD(("i2c_transfer: error: receive timeout\n"));
	ret = -4; goto i2c_transfer_finish;

	transfer_error_illegal_param:
	PRINTD(("i2c_transfer: error: illegal parameters\n"));
	ret = -5; goto i2c_transfer_finish;

	transfer_error_bus_busy:
	PRINTD(("i2c_transfer: error: bus is busy\n"));
	ret = -6; goto i2c_transfer_finish;

	i2c_transfer_finish:
	PRINTD(("i2c_transfer: ISR: 0x%04x\n", readl(&base->isr)));
	i2c_reset();
	return ret;
	}

	/* ------------------------------------------------------------------------ */
	/* API Functions */
	/* ------------------------------------------------------------------------ */
	void i2c_init(int speed, int slaveaddr)
	{
	#ifdef CONFIG_I2C_MULTI_BUS
	current_bus = 0;
	base = (struct mv_i2c *)i2c_regs[current_bus];
	#else
	base = (struct mv_i2c *)CONFIG_MV_I2C_REG;
	#endif

	i2c_board_init(base);
	}

	/*
	* i2c_probe: - Test if a chip answers for a given i2c address
	*
	* @chip: address of the chip which is searched for
	* @return: 0 if a chip was found, -1 otherwhise
	*/
	int i2c_probe(uchar chip)
	{
	struct i2c_msg msg;

	i2c_reset();

	msg.condition = I2C_COND_START;
	msg.acknack = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = (chip << 1) + 1;
	if (i2c_transfer(&msg))
	return -1;

	msg.condition = I2C_COND_STOP;
	msg.acknack = I2C_ACKNAK_SENDNAK;
	msg.direction = I2C_READ;
	msg.data = 0x00;
	if (i2c_transfer(&msg))
	return -1;

	return 0;
	}

	/*
	* i2c_read: - Read multiple bytes from an i2c device
	*
	* The higher level routines take into account that this function is only
	* called with len < page length of the device (see configuration file)
	*
	* @chip: address of the chip which is to be read
	* @addr: i2c data address within the chip
	* @alen: length of the i2c data address (1..2 bytes)
	* @buffer: where to write the data
	* @len: how much byte do we want to read
	* @return: 0 in case of success
	*/
	int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
	{
	struct i2c_msg msg;
	u8 addr_bytes[3]; /* lowest...highest byte of data address */

	PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
	"len=0x%02x)\n", chip, addr, alen, len));

	i2c_reset();

	/* dummy chip address write */
	PRINTD(("i2c_read: dummy chip address write\n"));
	msg.condition = I2C_COND_START;
	msg.acknack = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = (chip << 1);
	msg.data &= 0xFE;
	if (i2c_transfer(&msg))
	return -1;

	/*
	* send memory address bytes;
	* alen defines how much bytes we have to send.
	*/
	/addr &= ((1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)-1); /
	addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
	addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
	addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);

	while (--alen >= 0) {
	PRINTD(("i2c_read: send memory word address byte %1d\n", alen));
	msg.condition = I2C_COND_NORMAL;
	msg.acknack = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = addr_bytes[alen];
	if (i2c_transfer(&msg))
	return -1;
	}

	/* start read sequence */
	PRINTD(("i2c_read: start read sequence\n"));
	msg.condition = I2C_COND_START;
	msg.acknack = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = (chip << 1);
	msg.data \|= 0x01;
	if (i2c_transfer(&msg))
	return -1;

	/* read bytes; send NACK at last byte */
	while (len--) {
	if (len == 0) {
	msg.condition = I2C_COND_STOP;
	msg.acknack = I2C_ACKNAK_SENDNAK;
	} else {
	msg.condition = I2C_COND_NORMAL;
	msg.acknack = I2C_ACKNAK_SENDACK;
	}

	msg.direction = I2C_READ;
	msg.data = 0x00;
	if (i2c_transfer(&msg))
	return -1;

	*buffer = msg.data;
	PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",
	(unsigned int)buffer, *buffer));
	buffer++;
	}

	i2c_reset();

	return 0;
	}

	/*
	* i2c_write: - Write multiple bytes to an i2c device
	*
	* The higher level routines take into account that this function is only
	* called with len < page length of the device (see configuration file)
	*
	* @chip: address of the chip which is to be written
	* @addr: i2c data address within the chip
	* @alen: length of the i2c data address (1..2 bytes)
	* @buffer: where to find the data to be written
	* @len: how much byte do we want to read
	* @return: 0 in case of success
	*/
	int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
	{
	struct i2c_msg msg;
	u8 addr_bytes[3]; /* lowest...highest byte of data address */

	PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
	"len=0x%02x)\n", chip, addr, alen, len));

	i2c_reset();

	/* chip address write */
	PRINTD(("i2c_write: chip address write\n"));
	msg.condition = I2C_COND_START;
	msg.acknack = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = (chip << 1);
	msg.data &= 0xFE;
	if (i2c_transfer(&msg))
	return -1;

	/*
	* send memory address bytes;
	* alen defines how much bytes we have to send.
	*/
	addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
	addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
	addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);

	while (--alen >= 0) {
	PRINTD(("i2c_write: send memory word address\n"));
	msg.condition = I2C_COND_NORMAL;
	msg.acknack = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = addr_bytes[alen];
	if (i2c_transfer(&msg))
	return -1;
	}

	/* write bytes; send NACK at last byte */
	while (len--) {
	PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",
	(unsigned int)buffer, *buffer));

	if (len == 0)
	msg.condition = I2C_COND_STOP;
	else
	msg.condition = I2C_COND_NORMAL;

	msg.acknack = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = *(buffer++);

	if (i2c_transfer(&msg))
	return -1;
	}

	i2c_reset();

	return 0;
	}
	#endif /* CONFIG_HARD_I2C */