drivers/i2c/davinci_i2c.c - github/trini/u-boot - Gitiles

 /*
  * TI DaVinci (TMS320DM644x) I2C driver.
  *
  * (C) Copyright 2012-2014
  *     Texas Instruments Incorporated, <www.ti.com>
  * (C) Copyright 2007 Sergey Kubushyn <ksi@koi8.net>
  * --------------------------------------------------------
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */

 #include <common.h>
 #include <i2c.h>
 #include <asm/arch/hardware.h>
 #include <asm/arch/i2c_defs.h>
 #include <asm/io.h>
 #include "davinci_i2c.h"

 #define CHECK_NACK() \
 	do {\
 		if (tmp & (I2C_TIMEOUT | I2C_STAT_NACK)) {\
 			REG(&(i2c_base->i2c_con)) = 0;\
 			return 1;\
 		} \
 	} while (0)

 static struct i2c_regs *davinci_get_base(struct i2c_adapter *adap);

 static int wait_for_bus(struct i2c_adapter *adap)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);
 	int	stat, timeout;

 	REG(&(i2c_base->i2c_stat)) = 0xffff;

 	for (timeout = 0; timeout < 10; timeout++) {
 		stat = REG(&(i2c_base->i2c_stat));
 		if (!((stat) & I2C_STAT_BB)) {
 			REG(&(i2c_base->i2c_stat)) = 0xffff;
 			return 0;
 		}

 		REG(&(i2c_base->i2c_stat)) = stat;
 		udelay(50000);
 	}

 	REG(&(i2c_base->i2c_stat)) = 0xffff;
 	return 1;
 }


 static int poll_i2c_irq(struct i2c_adapter *adap, int mask)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);
 	int	stat, timeout;

 	for (timeout = 0; timeout < 10; timeout++) {
 		udelay(1000);
 		stat = REG(&(i2c_base->i2c_stat));
 		if (stat & mask)
 			return stat;
 	}

 	REG(&(i2c_base->i2c_stat)) = 0xffff;
 	return stat | I2C_TIMEOUT;
 }

 static void flush_rx(struct i2c_adapter *adap)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);

 	while (1) {
 		if (!(REG(&(i2c_base->i2c_stat)) & I2C_STAT_RRDY))
 			break;

 		REG(&(i2c_base->i2c_drr));
 		REG(&(i2c_base->i2c_stat)) = I2C_STAT_RRDY;
 		udelay(1000);
 	}
 }

 static uint davinci_i2c_setspeed(struct i2c_adapter *adap, uint speed)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);
 	uint32_t	div, psc;

 	psc = 2;
 	/* SCLL + SCLH */
 	div = (CONFIG_SYS_HZ_CLOCK / ((psc + 1) * speed)) - 10;
 	REG(&(i2c_base->i2c_psc)) = psc; /* 27MHz / (2 + 1) = 9MHz */
 	REG(&(i2c_base->i2c_scll)) = (div * 50) / 100; /* 50% Duty */
 	REG(&(i2c_base->i2c_sclh)) = div - REG(&(i2c_base->i2c_scll));

 	adap->speed	= speed;
 	return 0;
 }

 static void davinci_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);

 	if (REG(&(i2c_base->i2c_con)) & I2C_CON_EN) {
 		REG(&(i2c_base->i2c_con)) = 0;
 		udelay(50000);
 	}

 	davinci_i2c_setspeed(adap, speed);

 	REG(&(i2c_base->i2c_oa)) = slaveadd;
 	REG(&(i2c_base->i2c_cnt)) = 0;

 	/* Interrupts must be enabled or I2C module won't work */
 	REG(&(i2c_base->i2c_ie)) = I2C_IE_SCD_IE | I2C_IE_XRDY_IE |
 		I2C_IE_RRDY_IE | I2C_IE_ARDY_IE | I2C_IE_NACK_IE;

 	/* Now enable I2C controller (get it out of reset) */
 	REG(&(i2c_base->i2c_con)) = I2C_CON_EN;

 	udelay(1000);
 }

 static int davinci_i2c_probe(struct i2c_adapter *adap, uint8_t chip)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);
 	int	rc = 1;

 	if (chip == REG(&(i2c_base->i2c_oa)))
 		return rc;

 	REG(&(i2c_base->i2c_con)) = 0;
 	if (wait_for_bus(adap))
 		return 1;

 	/* try to read one byte from current (or only) address */
 	REG(&(i2c_base->i2c_cnt)) = 1;
 	REG(&(i2c_base->i2c_sa))  = chip;
 	REG(&(i2c_base->i2c_con)) = (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
 				     I2C_CON_STP);
 	udelay(50000);

 	if (!(REG(&(i2c_base->i2c_stat)) & I2C_STAT_NACK)) {
 		rc = 0;
 		flush_rx(adap);
 		REG(&(i2c_base->i2c_stat)) = 0xffff;
 	} else {
 		REG(&(i2c_base->i2c_stat)) = 0xffff;
 		REG(&(i2c_base->i2c_con)) |= I2C_CON_STP;
 		udelay(20000);
 		if (wait_for_bus(adap))
 			return 1;
 	}

 	flush_rx(adap);
 	REG(&(i2c_base->i2c_stat)) = 0xffff;
 	REG(&(i2c_base->i2c_cnt)) = 0;
 	return rc;
 }

 static int davinci_i2c_read(struct i2c_adapter *adap, uint8_t chip,
 				uint32_t addr, int alen, uint8_t *buf, int len)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);
 	uint32_t	tmp;
 	int		i;

 	if ((alen < 0) || (alen > 2)) {
 		printf("%s(): bogus address length %x\n", __func__, alen);
 		return 1;
 	}

 	if (wait_for_bus(adap))
 		return 1;

 	if (alen != 0) {
 		/* Start address phase */
 		tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX;
 		REG(&(i2c_base->i2c_cnt)) = alen;
 		REG(&(i2c_base->i2c_sa)) = chip;
 		REG(&(i2c_base->i2c_con)) = tmp;

 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);

 		CHECK_NACK();

 		switch (alen) {
 		case 2:
 			/* Send address MSByte */
 			if (tmp & I2C_STAT_XRDY) {
 				REG(&(i2c_base->i2c_dxr)) = (addr >> 8) & 0xff;
 			} else {
 				REG(&(i2c_base->i2c_con)) = 0;
 				return 1;
 			}

 			tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);

 			CHECK_NACK();
 			/* No break, fall through */
 		case 1:
 			/* Send address LSByte */
 			if (tmp & I2C_STAT_XRDY) {
 				REG(&(i2c_base->i2c_dxr)) = addr & 0xff;
 			} else {
 				REG(&(i2c_base->i2c_con)) = 0;
 				return 1;
 			}

 			tmp = poll_i2c_irq(adap, I2C_STAT_XRDY |
 					   I2C_STAT_NACK | I2C_STAT_ARDY);

 			CHECK_NACK();

 			if (!(tmp & I2C_STAT_ARDY)) {
 				REG(&(i2c_base->i2c_con)) = 0;
 				return 1;
 			}
 		}
 	}

 	/* Address phase is over, now read 'len' bytes and stop */
 	tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP;
 	REG(&(i2c_base->i2c_cnt)) = len & 0xffff;
 	REG(&(i2c_base->i2c_sa)) = chip;
 	REG(&(i2c_base->i2c_con)) = tmp;

 	for (i = 0; i < len; i++) {
 		tmp = poll_i2c_irq(adap, I2C_STAT_RRDY | I2C_STAT_NACK |
 				   I2C_STAT_ROVR);

 		CHECK_NACK();

 		if (tmp & I2C_STAT_RRDY) {
 			buf[i] = REG(&(i2c_base->i2c_drr));
 		} else {
 			REG(&(i2c_base->i2c_con)) = 0;
 			return 1;
 		}
 	}

 	tmp = poll_i2c_irq(adap, I2C_STAT_SCD | I2C_STAT_NACK);

 	CHECK_NACK();

 	if (!(tmp & I2C_STAT_SCD)) {
 		REG(&(i2c_base->i2c_con)) = 0;
 		return 1;
 	}

 	flush_rx(adap);
 	REG(&(i2c_base->i2c_stat)) = 0xffff;
 	REG(&(i2c_base->i2c_cnt)) = 0;
 	REG(&(i2c_base->i2c_con)) = 0;

 	return 0;
 }

 static int davinci_i2c_write(struct i2c_adapter *adap, uint8_t chip,
 				uint32_t addr, int alen, uint8_t *buf, int len)
 {
 	struct i2c_regs *i2c_base = davinci_get_base(adap);
 	uint32_t	tmp;
 	int		i;

 	if ((alen < 0) || (alen > 2)) {
 		printf("%s(): bogus address length %x\n", __func__, alen);
 		return 1;
 	}
 	if (len < 0) {
 		printf("%s(): bogus length %x\n", __func__, len);
 		return 1;
 	}

 	if (wait_for_bus(adap))
 		return 1;

 	/* Start address phase */
 	tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
 		I2C_CON_TRX | I2C_CON_STP;
 	REG(&(i2c_base->i2c_cnt)) = (alen == 0) ?
 		len & 0xffff : (len & 0xffff) + alen;
 	REG(&(i2c_base->i2c_sa)) = chip;
 	REG(&(i2c_base->i2c_con)) = tmp;

 	switch (alen) {
 	case 2:
 		/* Send address MSByte */
 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);

 		CHECK_NACK();

 		if (tmp & I2C_STAT_XRDY) {
 			REG(&(i2c_base->i2c_dxr)) = (addr >> 8) & 0xff;
 		} else {
 			REG(&(i2c_base->i2c_con)) = 0;
 			return 1;
 		}
 		/* No break, fall through */
 	case 1:
 		/* Send address LSByte */
 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);

 		CHECK_NACK();

 		if (tmp & I2C_STAT_XRDY) {
 			REG(&(i2c_base->i2c_dxr)) = addr & 0xff;
 		} else {
 			REG(&(i2c_base->i2c_con)) = 0;
 			return 1;
 		}
 	}

 	for (i = 0; i < len; i++) {
 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);

 		CHECK_NACK();

 		if (tmp & I2C_STAT_XRDY)
 			REG(&(i2c_base->i2c_dxr)) = buf[i];
 		else
 			return 1;
 	}

 	tmp = poll_i2c_irq(adap, I2C_STAT_SCD | I2C_STAT_NACK);

 	CHECK_NACK();

 	if (!(tmp & I2C_STAT_SCD)) {
 		REG(&(i2c_base->i2c_con)) = 0;
 		return 1;
 	}

 	flush_rx(adap);
 	REG(&(i2c_base->i2c_stat)) = 0xffff;
 	REG(&(i2c_base->i2c_cnt)) = 0;
 	REG(&(i2c_base->i2c_con)) = 0;

 	return 0;
 }

 static struct i2c_regs *davinci_get_base(struct i2c_adapter *adap)
 {
 	switch (adap->hwadapnr) {
 #if I2C_BUS_MAX >= 3
 	case 2:
 		return (struct i2c_regs *)I2C2_BASE;
 #endif
 #if I2C_BUS_MAX >= 2
 	case 1:
 		return (struct i2c_regs *)I2C1_BASE;
 #endif
 	case 0:
 		return (struct i2c_regs *)I2C_BASE;

 	default:
 		printf("wrong hwadapnr: %d\n", adap->hwadapnr);
 	}

 	return NULL;
 }

 U_BOOT_I2C_ADAP_COMPLETE(davinci_0, davinci_i2c_init, davinci_i2c_probe,
 			 davinci_i2c_read, davinci_i2c_write,
 			 davinci_i2c_setspeed,
 			 CONFIG_SYS_DAVINCI_I2C_SPEED,
 			 CONFIG_SYS_DAVINCI_I2C_SLAVE,
 			 0)

 #if I2C_BUS_MAX >= 2
 U_BOOT_I2C_ADAP_COMPLETE(davinci_1, davinci_i2c_init, davinci_i2c_probe,
 			 davinci_i2c_read, davinci_i2c_write,
 			 davinci_i2c_setspeed,
 			 CONFIG_SYS_DAVINCI_I2C_SPEED1,
 			 CONFIG_SYS_DAVINCI_I2C_SLAVE1,
 			 1)
 #endif

 #if I2C_BUS_MAX >= 3
 U_BOOT_I2C_ADAP_COMPLETE(davinci_2, davinci_i2c_init, davinci_i2c_probe,
 			 davinci_i2c_read, davinci_i2c_write,
 			 davinci_i2c_setspeed,
 			 CONFIG_SYS_DAVINCI_I2C_SPEED2,
 			 CONFIG_SYS_DAVINCI_I2C_SLAVE2,
 			 2)
 #endif
	/*
	* TI DaVinci (TMS320DM644x) I2C driver.
	*
	* (C) Copyright 2012-2014
	* Texas Instruments Incorporated, <www.ti.com>
	* (C) Copyright 2007 Sergey Kubushyn <ksi@koi8.net>
	* --------------------------------------------------------
	*
	* SPDX-License-Identifier: GPL-2.0+
	*/

	#include <common.h>
	#include <i2c.h>
	#include <asm/arch/hardware.h>
	#include <asm/arch/i2c_defs.h>
	#include <asm/io.h>
	#include "davinci_i2c.h"

	#define CHECK_NACK() \
	do {\
	if (tmp & (I2C_TIMEOUT \| I2C_STAT_NACK)) {\
	REG(&(i2c_base->i2c_con)) = 0;\
	return 1;\
	} \
	} while (0)

	static struct i2c_regs davinci_get_base(struct i2c_adapter adap);

	static int wait_for_bus(struct i2c_adapter *adap)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);
	int stat, timeout;

	REG(&(i2c_base->i2c_stat)) = 0xffff;

	for (timeout = 0; timeout < 10; timeout++) {
	stat = REG(&(i2c_base->i2c_stat));
	if (!((stat) & I2C_STAT_BB)) {
	REG(&(i2c_base->i2c_stat)) = 0xffff;
	return 0;
	}

	REG(&(i2c_base->i2c_stat)) = stat;
	udelay(50000);
	}

	REG(&(i2c_base->i2c_stat)) = 0xffff;
	return 1;
	}


	static int poll_i2c_irq(struct i2c_adapter *adap, int mask)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);
	int stat, timeout;

	for (timeout = 0; timeout < 10; timeout++) {
	udelay(1000);
	stat = REG(&(i2c_base->i2c_stat));
	if (stat & mask)
	return stat;
	}

	REG(&(i2c_base->i2c_stat)) = 0xffff;
	return stat \| I2C_TIMEOUT;
	}

	static void flush_rx(struct i2c_adapter *adap)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);

	while (1) {
	if (!(REG(&(i2c_base->i2c_stat)) & I2C_STAT_RRDY))
	break;

	REG(&(i2c_base->i2c_drr));
	REG(&(i2c_base->i2c_stat)) = I2C_STAT_RRDY;
	udelay(1000);
	}
	}

	static uint davinci_i2c_setspeed(struct i2c_adapter *adap, uint speed)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);
	uint32_t div, psc;

	psc = 2;
	/* SCLL + SCLH */
	div = (CONFIG_SYS_HZ_CLOCK / ((psc + 1) * speed)) - 10;
	REG(&(i2c_base->i2c_psc)) = psc; /* 27MHz / (2 + 1) = 9MHz */
	REG(&(i2c_base->i2c_scll)) = (div * 50) / 100; /* 50% Duty */
	REG(&(i2c_base->i2c_sclh)) = div - REG(&(i2c_base->i2c_scll));

	adap->speed = speed;
	return 0;
	}

	static void davinci_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);

	if (REG(&(i2c_base->i2c_con)) & I2C_CON_EN) {
	REG(&(i2c_base->i2c_con)) = 0;
	udelay(50000);
	}

	davinci_i2c_setspeed(adap, speed);

	REG(&(i2c_base->i2c_oa)) = slaveadd;
	REG(&(i2c_base->i2c_cnt)) = 0;

	/* Interrupts must be enabled or I2C module won't work */
	REG(&(i2c_base->i2c_ie)) = I2C_IE_SCD_IE \| I2C_IE_XRDY_IE \|
	I2C_IE_RRDY_IE \| I2C_IE_ARDY_IE \| I2C_IE_NACK_IE;

	/* Now enable I2C controller (get it out of reset) */
	REG(&(i2c_base->i2c_con)) = I2C_CON_EN;

	udelay(1000);
	}

	static int davinci_i2c_probe(struct i2c_adapter *adap, uint8_t chip)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);
	int rc = 1;

	if (chip == REG(&(i2c_base->i2c_oa)))
	return rc;

	REG(&(i2c_base->i2c_con)) = 0;
	if (wait_for_bus(adap))
	return 1;

	/* try to read one byte from current (or only) address */
	REG(&(i2c_base->i2c_cnt)) = 1;
	REG(&(i2c_base->i2c_sa)) = chip;
	REG(&(i2c_base->i2c_con)) = (I2C_CON_EN \| I2C_CON_MST \| I2C_CON_STT \|
	I2C_CON_STP);
	udelay(50000);

	if (!(REG(&(i2c_base->i2c_stat)) & I2C_STAT_NACK)) {
	rc = 0;
	flush_rx(adap);
	REG(&(i2c_base->i2c_stat)) = 0xffff;
	} else {
	REG(&(i2c_base->i2c_stat)) = 0xffff;
	REG(&(i2c_base->i2c_con)) \|= I2C_CON_STP;
	udelay(20000);
	if (wait_for_bus(adap))
	return 1;
	}

	flush_rx(adap);
	REG(&(i2c_base->i2c_stat)) = 0xffff;
	REG(&(i2c_base->i2c_cnt)) = 0;
	return rc;
	}

	static int davinci_i2c_read(struct i2c_adapter *adap, uint8_t chip,
	uint32_t addr, int alen, uint8_t *buf, int len)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);
	uint32_t tmp;
	int i;

	if ((alen < 0) \|\| (alen > 2)) {
	printf("%s(): bogus address length %x\n", __func__, alen);
	return 1;
	}

	if (wait_for_bus(adap))
	return 1;

	if (alen != 0) {
	/* Start address phase */
	tmp = I2C_CON_EN \| I2C_CON_MST \| I2C_CON_STT \| I2C_CON_TRX;
	REG(&(i2c_base->i2c_cnt)) = alen;
	REG(&(i2c_base->i2c_sa)) = chip;
	REG(&(i2c_base->i2c_con)) = tmp;

	tmp = poll_i2c_irq(adap, I2C_STAT_XRDY \| I2C_STAT_NACK);

	CHECK_NACK();

	switch (alen) {
	case 2:
	/* Send address MSByte */
	if (tmp & I2C_STAT_XRDY) {
	REG(&(i2c_base->i2c_dxr)) = (addr >> 8) & 0xff;
	} else {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}

	tmp = poll_i2c_irq(adap, I2C_STAT_XRDY \| I2C_STAT_NACK);

	CHECK_NACK();
	/* No break, fall through */
	case 1:
	/* Send address LSByte */
	if (tmp & I2C_STAT_XRDY) {
	REG(&(i2c_base->i2c_dxr)) = addr & 0xff;
	} else {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}

	tmp = poll_i2c_irq(adap, I2C_STAT_XRDY \|
	I2C_STAT_NACK \| I2C_STAT_ARDY);

	CHECK_NACK();

	if (!(tmp & I2C_STAT_ARDY)) {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}
	}
	}

	/* Address phase is over, now read 'len' bytes and stop */
	tmp = I2C_CON_EN \| I2C_CON_MST \| I2C_CON_STT \| I2C_CON_STP;
	REG(&(i2c_base->i2c_cnt)) = len & 0xffff;
	REG(&(i2c_base->i2c_sa)) = chip;
	REG(&(i2c_base->i2c_con)) = tmp;

	for (i = 0; i < len; i++) {
	tmp = poll_i2c_irq(adap, I2C_STAT_RRDY \| I2C_STAT_NACK \|
	I2C_STAT_ROVR);

	CHECK_NACK();

	if (tmp & I2C_STAT_RRDY) {
	buf[i] = REG(&(i2c_base->i2c_drr));
	} else {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}
	}

	tmp = poll_i2c_irq(adap, I2C_STAT_SCD \| I2C_STAT_NACK);

	CHECK_NACK();

	if (!(tmp & I2C_STAT_SCD)) {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}

	flush_rx(adap);
	REG(&(i2c_base->i2c_stat)) = 0xffff;
	REG(&(i2c_base->i2c_cnt)) = 0;
	REG(&(i2c_base->i2c_con)) = 0;

	return 0;
	}

	static int davinci_i2c_write(struct i2c_adapter *adap, uint8_t chip,
	uint32_t addr, int alen, uint8_t *buf, int len)
	{
	struct i2c_regs *i2c_base = davinci_get_base(adap);
	uint32_t tmp;
	int i;

	if ((alen < 0) \|\| (alen > 2)) {
	printf("%s(): bogus address length %x\n", __func__, alen);
	return 1;
	}
	if (len < 0) {
	printf("%s(): bogus length %x\n", __func__, len);
	return 1;
	}

	if (wait_for_bus(adap))
	return 1;

	/* Start address phase */
	tmp = I2C_CON_EN \| I2C_CON_MST \| I2C_CON_STT \|
	I2C_CON_TRX \| I2C_CON_STP;
	REG(&(i2c_base->i2c_cnt)) = (alen == 0) ?
	len & 0xffff : (len & 0xffff) + alen;
	REG(&(i2c_base->i2c_sa)) = chip;
	REG(&(i2c_base->i2c_con)) = tmp;

	switch (alen) {
	case 2:
	/* Send address MSByte */
	tmp = poll_i2c_irq(adap, I2C_STAT_XRDY \| I2C_STAT_NACK);

	CHECK_NACK();

	if (tmp & I2C_STAT_XRDY) {
	REG(&(i2c_base->i2c_dxr)) = (addr >> 8) & 0xff;
	} else {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}
	/* No break, fall through */
	case 1:
	/* Send address LSByte */
	tmp = poll_i2c_irq(adap, I2C_STAT_XRDY \| I2C_STAT_NACK);

	CHECK_NACK();

	if (tmp & I2C_STAT_XRDY) {
	REG(&(i2c_base->i2c_dxr)) = addr & 0xff;
	} else {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}
	}

	for (i = 0; i < len; i++) {
	tmp = poll_i2c_irq(adap, I2C_STAT_XRDY \| I2C_STAT_NACK);

	CHECK_NACK();

	if (tmp & I2C_STAT_XRDY)
	REG(&(i2c_base->i2c_dxr)) = buf[i];
	else
	return 1;
	}

	tmp = poll_i2c_irq(adap, I2C_STAT_SCD \| I2C_STAT_NACK);

	CHECK_NACK();

	if (!(tmp & I2C_STAT_SCD)) {
	REG(&(i2c_base->i2c_con)) = 0;
	return 1;
	}

	flush_rx(adap);
	REG(&(i2c_base->i2c_stat)) = 0xffff;
	REG(&(i2c_base->i2c_cnt)) = 0;
	REG(&(i2c_base->i2c_con)) = 0;

	return 0;
	}

	static struct i2c_regs davinci_get_base(struct i2c_adapter adap)
	{
	switch (adap->hwadapnr) {
	#if I2C_BUS_MAX >= 3
	case 2:
	return (struct i2c_regs *)I2C2_BASE;
	#endif
	#if I2C_BUS_MAX >= 2
	case 1:
	return (struct i2c_regs *)I2C1_BASE;
	#endif
	case 0:
	return (struct i2c_regs *)I2C_BASE;

	default:
	printf("wrong hwadapnr: %d\n", adap->hwadapnr);
	}

	return NULL;
	}

	U_BOOT_I2C_ADAP_COMPLETE(davinci_0, davinci_i2c_init, davinci_i2c_probe,
	davinci_i2c_read, davinci_i2c_write,
	davinci_i2c_setspeed,
	CONFIG_SYS_DAVINCI_I2C_SPEED,
	CONFIG_SYS_DAVINCI_I2C_SLAVE,
	0)

	#if I2C_BUS_MAX >= 2
	U_BOOT_I2C_ADAP_COMPLETE(davinci_1, davinci_i2c_init, davinci_i2c_probe,
	davinci_i2c_read, davinci_i2c_write,
	davinci_i2c_setspeed,
	CONFIG_SYS_DAVINCI_I2C_SPEED1,
	CONFIG_SYS_DAVINCI_I2C_SLAVE1,
	1)
	#endif

	#if I2C_BUS_MAX >= 3
	U_BOOT_I2C_ADAP_COMPLETE(davinci_2, davinci_i2c_init, davinci_i2c_probe,
	davinci_i2c_read, davinci_i2c_write,
	davinci_i2c_setspeed,
	CONFIG_SYS_DAVINCI_I2C_SPEED2,
	CONFIG_SYS_DAVINCI_I2C_SLAVE2,
	2)
	#endif