Initial revision

1 files changed, 733 insertions, 0 deletions

diff --git a/cpu/mpc8260/i2c.c b/cpu/mpc8260/i2c.c
new file mode 100644
index 0000000000..8bfa2e8e74
--- /dev/null
+++ b/cpu/mpc8260/i2c.c
@@ -0,0 +1,733 @@
+/*
+ * (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>
+ *
+ * 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>
+
+#if defined(CONFIG_HARD_I2C)
+
+#include <asm/cpm_8260.h>
+#include <i2c.h>
+
+/* define to enable debug messages */
+#undef  DEBUG_I2C
+
+/* uSec to wait between polls of the i2c */
+#define DELAY_US	100
+/* uSec to wait for the CPM to start processing the buffer */
+#define START_DELAY_US	1000
+
+/*
+ * tx/rx per-byte timeout: we delay DELAY_US uSec between polls so the
+ * timeout will be (tx_length + rx_length) * DELAY_US * TOUT_LOOP
+ */
+#define TOUT_LOOP 5
+
+/*-----------------------------------------------------------------------
+ * Set default values
+ */
+#ifndef	CFG_I2C_SPEED
+#define	CFG_I2C_SPEED	50000
+#endif
+
+#ifndef	CFG_I2C_SLAVE
+#define	CFG_I2C_SLAVE	0xFE
+#endif
+/*-----------------------------------------------------------------------
+ */
+
+typedef void (*i2c_ecb_t)(int, int);    /* error callback function */
+
+/* This structure keeps track of the bd and buffer space usage. */
+typedef struct i2c_state {
+	int		rx_idx;		/* index   to next free Rx BD */
+	int		tx_idx;		/* index   to next free Tx BD */
+	void		*rxbd;		/* pointer to next free Rx BD */
+	void		*txbd;		/* pointer to next free Tx BD */
+	int		tx_space;	/* number  of Tx bytes left   */
+	unsigned char	*tx_buf;	/* pointer to free Tx area    */
+	i2c_ecb_t	err_cb;		/* error callback function    */
+} i2c_state_t;
+
+/* flags for i2c_send() and i2c_receive() */
+#define	I2CF_ENABLE_SECONDARY	0x01	/* secondary_address is valid	*/
+#define	I2CF_START_COND		0x02	/* tx: generate start condition	*/
+#define I2CF_STOP_COND		0x04	/* tx: generate stop  condition	*/
+
+/* return codes */
+#define I2CERR_NO_BUFFERS	0x01	/* no more BDs or buffer space	*/
+#define I2CERR_MSG_TOO_LONG	0x02	/* tried to send/receive to much data   */
+#define I2CERR_TIMEOUT		0x03	/* timeout in i2c_doio()	*/
+#define I2CERR_QUEUE_EMPTY	0x04	/* i2c_doio called without send/receive */
+
+/* error callback flags */
+#define I2CECB_RX_ERR		0x10	/* this is a receive error	*/
+#define     I2CECB_RX_ERR_OV	0x02	/* receive overrun error	*/
+#define     I2CECB_RX_MASK	0x0f	/* mask for error bits		*/
+#define I2CECB_TX_ERR		0x20	/* this is a transmit error	*/
+#define     I2CECB_TX_CL	0x01	/* transmit collision error	*/
+#define     I2CECB_TX_UN	0x02	/* transmit underflow error	*/
+#define     I2CECB_TX_NAK	0x04	/* transmit no ack error	*/
+#define     I2CECB_TX_MASK	0x0f	/* mask for error bits		*/
+#define I2CECB_TIMEOUT		0x40	/* this is a timeout error	*/
+
+#define ERROR_I2C_NONE		0
+#define ERROR_I2C_LENGTH	1
+
+#define I2C_WRITE_BIT		0x00
+#define I2C_READ_BIT		0x01
+
+#define I2C_RXTX_LEN	128	/* maximum tx/rx buffer length */
+
+
+#define NUM_RX_BDS 4
+#define NUM_TX_BDS 4
+#define MAX_TX_SPACE 256
+
+typedef struct I2C_BD
+{
+  unsigned short status;
+  unsigned short length;
+  unsigned char *addr;
+} I2C_BD;
+#define BD_I2C_TX_START 0x0400  /* special status for i2c: Start condition */
+
+#define BD_I2C_TX_CL	0x0001	/* collision error */
+#define BD_I2C_TX_UN	0x0002	/* underflow error */
+#define BD_I2C_TX_NAK	0x0004	/* no acknowledge error */
+#define BD_I2C_TX_ERR	(BD_I2C_TX_NAK|BD_I2C_TX_UN|BD_I2C_TX_CL)
+
+#define BD_I2C_RX_ERR	BD_SC_OV
+
+#ifdef DEBUG_I2C
+#define PRINTD(x) printf x
+#else
+#define PRINTD(x)
+#endif
+
+/*
+ * Returns the best value of I2BRG to meet desired clock speed of I2C with
+ * input parameters (clock speed, filter, and predivider value).
+ * It returns computer speed value and the difference between it and desired
+ * speed.
+ */
+static inline int
+i2c_roundrate(int hz, int speed, int filter, int modval,
+		int *brgval, int *totspeed)
+{
+    int moddiv = 1 << (5-(modval & 3)), brgdiv, div;
+
+    PRINTD(("\t[I2C] trying hz=%d, speed=%d, filter=%d, modval=%d\n",
+	hz, speed, filter, modval));
+
+    div = moddiv * speed;
+    brgdiv = (hz + div - 1) / div;
+
+    PRINTD(("\t\tmoddiv=%d, brgdiv=%d\n", moddiv, brgdiv));
+
+    *brgval = (brgdiv / 2) - 3 - (2*filter);
+
+    if ((*brgval < 0) || (*brgval > 255)) {
+	  PRINTD(("\t\trejected brgval=%d\n", *brgval));
+	  return -1;
+    }
+
+    brgdiv = 2 * (*brgval + 3 + (2 * filter));
+    div = moddiv * brgdiv ;
+    *totspeed = (hz + div - 1) / div;
+
+    PRINTD(("\t\taccepted brgval=%d, totspeed=%d\n", *brgval, *totspeed));
+
+    return  0;
+}
+
+/*
+ * Sets the I2C clock predivider and divider to meet required clock speed.
+ */
+static int i2c_setrate(int hz, int speed)
+{
+    immap_t	*immap = (immap_t *)CFG_IMMR ;
+    volatile i2c8260_t *i2c = (i2c8260_t *)&immap->im_i2c;
+    int brgval,
+	  modval,	/* 0-3 */
+	  bestspeed_diff = speed,
+	  bestspeed_brgval=0,
+	  bestspeed_modval=0,
+	  bestspeed_filter=0,
+	  totspeed,
+	  filter = 0; /* Use this fixed value */
+
+	for (modval = 0; modval < 4; modval++)
+	{
+		if (i2c_roundrate (hz, speed, filter, modval, &brgval, &totspeed) == 0)
+		{
+			int diff = speed - totspeed ;
+
+			if ((diff >= 0) && (diff < bestspeed_diff))
+			{
+				bestspeed_diff 	= diff ;
+				bestspeed_modval 	= modval;
+				bestspeed_brgval 	= brgval;
+				bestspeed_filter 	= filter;
+			}
+		}
+	}
+
+    PRINTD(("[I2C] Best is:\n"));
+    PRINTD(("[I2C] CPU=%dhz RATE=%d F=%d I2MOD=%08x I2BRG=%08x DIFF=%dhz\n",
+		   hz, speed,
+		   bestspeed_filter, bestspeed_modval, bestspeed_brgval,
+		   bestspeed_diff));
+
+    i2c->i2c_i2mod |= ((bestspeed_modval & 3) << 1) | (bestspeed_filter << 3);
+    i2c->i2c_i2brg = bestspeed_brgval & 0xff;
+
+    PRINTD(("[I2C] i2mod=%08x i2brg=%08x\n", i2c->i2c_i2mod, i2c->i2c_i2brg));
+
+    return 1 ;
+}
+
+void i2c_init(int speed, int slaveadd)
+{
+	DECLARE_GLOBAL_DATA_PTR;
+
+	volatile immap_t *immap = (immap_t *)CFG_IMMR ;
+	volatile cpm8260_t *cp = (cpm8260_t *)&immap->im_cpm;
+	volatile i2c8260_t *i2c	= (i2c8260_t *)&immap->im_i2c;
+	volatile iic_t *iip;
+	ulong rbase, tbase;
+	volatile I2C_BD *rxbd, *txbd;
+	uint dpaddr;
+
+	dpaddr = *((unsigned short*)(&immap->im_dprambase[PROFF_I2C_BASE]));
+	if (dpaddr == 0) {
+	    /* need to allocate dual port ram */
+	    dpaddr = m8260_cpm_dpalloc(64 +
+		(NUM_RX_BDS * sizeof(I2C_BD)) + (NUM_TX_BDS * sizeof(I2C_BD)) +
+		MAX_TX_SPACE, 64);
+	    *((unsigned short*)(&immap->im_dprambase[PROFF_I2C_BASE])) = dpaddr;
+	}
+
+	/*
+	 * initialise data in dual port ram:
+	 *
+	 * 	  dpaddr -> parameter ram (64 bytes)
+	 *         rbase -> rx BD         (NUM_RX_BDS * sizeof(I2C_BD) bytes)
+	 *         tbase -> tx BD         (NUM_TX_BDS * sizeof(I2C_BD) bytes)
+	 *                  tx buffer     (MAX_TX_SPACE bytes)
+	 */
+
+	iip = (iic_t *)&immap->im_dprambase[dpaddr];
+	memset((void*)iip, 0, sizeof(iic_t));
+
+	rbase = dpaddr + 64;
+	tbase = rbase + NUM_RX_BDS * sizeof(I2C_BD);
+
+	/* Disable interrupts */
+	i2c->i2c_i2mod = 0x00;
+	i2c->i2c_i2cmr = 0x00;
+	i2c->i2c_i2cer = 0xff;
+	i2c->i2c_i2add = slaveadd;
+
+	/*
+	 * Set the I2C BRG Clock division factor from desired i2c rate
+	 * and current CPU rate (we assume sccr dfbgr field is 0;
+	 * divide BRGCLK by 1)
+	 */
+	PRINTD(("[I2C] Setting rate...\n"));
+	i2c_setrate (gd->brg_clk, CFG_I2C_SPEED) ;
+
+	/* Set I2C controller in master mode */
+	i2c->i2c_i2com = 0x01;
+
+	/* Initialize Tx/Rx parameters */
+	iip->iic_rbase = rbase;
+	iip->iic_tbase = tbase;
+	rxbd = (I2C_BD *)((unsigned char *)&immap->im_dprambase[iip->iic_rbase]);
+	txbd = (I2C_BD *)((unsigned char *)&immap->im_dprambase[iip->iic_tbase]);
+
+	PRINTD(("[I2C] rbase = %04x\n", iip->iic_rbase));
+	PRINTD(("[I2C] tbase = %04x\n", iip->iic_tbase));
+	PRINTD(("[I2C] rxbd = %08x\n", (int)rxbd));
+	PRINTD(("[I2C] txbd = %08x\n", (int)txbd));
+
+	/* Set big endian byte order */
+	iip->iic_tfcr = 0x10;
+	iip->iic_rfcr = 0x10;
+
+	/* Set maximum receive size. */
+	iip->iic_mrblr = I2C_RXTX_LEN;
+
+    cp->cp_cpcr = mk_cr_cmd(CPM_CR_I2C_PAGE,
+							CPM_CR_I2C_SBLOCK,
+							0x00,
+							CPM_CR_INIT_TRX) | CPM_CR_FLG;
+    do {
+		__asm__ __volatile__ ("eieio");
+    } while (cp->cp_cpcr & CPM_CR_FLG);
+
+	/* Clear events and interrupts */
+	i2c->i2c_i2cer = 0xff;
+	i2c->i2c_i2cmr = 0x00;
+}
+
+static
+void i2c_newio(i2c_state_t *state)
+{
+	volatile immap_t *immap = (immap_t *)CFG_IMMR ;
+	volatile iic_t *iip;
+	uint dpaddr;
+
+	PRINTD(("[I2C] i2c_newio\n"));
+
+	dpaddr = *((unsigned short*)(&immap->im_dprambase[PROFF_I2C_BASE]));
+	iip = (iic_t *)&immap->im_dprambase[dpaddr];
+	state->rx_idx = 0;
+	state->tx_idx = 0;
+	state->rxbd = (void*)&immap->im_dprambase[iip->iic_rbase];
+	state->txbd = (void*)&immap->im_dprambase[iip->iic_tbase];
+	state->tx_space = MAX_TX_SPACE;
+	state->tx_buf = (uchar*)state->txbd + NUM_TX_BDS * sizeof(I2C_BD);
+	state->err_cb = NULL;
+
+	PRINTD(("[I2C] rxbd = %08x\n", (int)state->rxbd));
+	PRINTD(("[I2C] txbd = %08x\n", (int)state->txbd));
+	PRINTD(("[I2C] tx_buf = %08x\n", (int)state->tx_buf));
+
+	/* clear the buffer memory */
+	memset((char *)state->tx_buf, 0, MAX_TX_SPACE);
+}
+
+static
+int i2c_send(i2c_state_t *state,
+			 unsigned char address,
+			 unsigned char secondary_address,
+			 unsigned int flags,
+			 unsigned short size,
+			 unsigned char *dataout)
+{
+	volatile I2C_BD *txbd;
+	int i,j;
+
+	PRINTD(("[I2C] i2c_send add=%02d sec=%02d flag=%02d size=%d\n",
+			address, secondary_address, flags, size));
+
+	/* trying to send message larger than BD */
+	if (size > I2C_RXTX_LEN)
+	  return I2CERR_MSG_TOO_LONG;
+
+	/* no more free bds */
+	if (state->tx_idx >= NUM_TX_BDS || state->tx_space < (2 + size))
+	  return I2CERR_NO_BUFFERS;
+
+	txbd = (I2C_BD *)state->txbd;
+	txbd->addr = state->tx_buf;
+
+	PRINTD(("[I2C] txbd = %08x\n", (int)txbd));
+
+    if (flags & I2CF_START_COND)
+    {
+	PRINTD(("[I2C] Formatting addresses...\n"));
+	if (flags & I2CF_ENABLE_SECONDARY)
+	{
+		txbd->length = size + 2;  /* Length of message plus dest addresses */
+		txbd->addr[0] = address << 1;
+		txbd->addr[1] = secondary_address;
+		i = 2;
+	}
+	else
+	{
+		txbd->length = size + 1;  /* Length of message plus dest address */
+		txbd->addr[0] = address << 1;  /* Write destination address to BD */
+		i = 1;
+	}
+    }
+    else
+    {
+	txbd->length = size;  /* Length of message */
+	i = 0;
+    }
+
+	/* set up txbd */
+	txbd->status = BD_SC_READY;
+	if (flags & I2CF_START_COND)
+	  txbd->status |= BD_I2C_TX_START;
+	if (flags & I2CF_STOP_COND)
+	  txbd->status |= BD_SC_LAST | BD_SC_WRAP;
+
+	/* Copy data to send into buffer */
+	PRINTD(("[I2C] copy data...\n"));
+	for(j = 0; j < size; i++, j++)
+	  txbd->addr[i] = dataout[j];
+
+	PRINTD(("[I2C] txbd: length=0x%04x status=0x%04x addr[0]=0x%02x addr[1]=0x%02x\n",
+		   txbd->length,
+		   txbd->status,
+		   txbd->addr[0],
+		   txbd->addr[1]));
+
+	/* advance state */
+	state->tx_buf += txbd->length;
+	state->tx_space -= txbd->length;
+	state->tx_idx++;
+	state->txbd = (void*)(txbd + 1);
+
+	return 0;
+}
+
+static
+int i2c_receive(i2c_state_t *state,
+				unsigned char address,
+				unsigned char secondary_address,
+				unsigned int flags,
+				unsigned short size_to_expect,
+				unsigned char *datain)
+{
+	volatile I2C_BD *rxbd, *txbd;
+
+	PRINTD(("[I2C] i2c_receive %02d %02d %02d\n", address, secondary_address, flags));
+
+	/* Expected to receive too much */
+	if (size_to_expect > I2C_RXTX_LEN)
+	  return I2CERR_MSG_TOO_LONG;
+
+	/* no more free bds */
+	if (state->tx_idx >= NUM_TX_BDS || state->rx_idx >= NUM_RX_BDS
+		 || state->tx_space < 2)
+	  return I2CERR_NO_BUFFERS;
+
+	rxbd = (I2C_BD *)state->rxbd;
+	txbd = (I2C_BD *)state->txbd;
+
+	PRINTD(("[I2C] rxbd = %08x\n", (int)rxbd));
+	PRINTD(("[I2C] txbd = %08x\n", (int)txbd));
+
+	txbd->addr = state->tx_buf;
+
+	/* set up TXBD for destination address */
+	if (flags & I2CF_ENABLE_SECONDARY)
+	{
+		txbd->length = 2;
+		txbd->addr[0] = address << 1;   /* Write data */
+		txbd->addr[1] = secondary_address;  /* Internal address */
+		txbd->status = BD_SC_READY;
+	}
+	else
+	{
+		txbd->length = 1 + size_to_expect;
+		txbd->addr[0] = (address << 1) | 0x01;
+		txbd->status = BD_SC_READY;
+		memset(&txbd->addr[1], 0, txbd->length);
+	}
+
+	/* set up rxbd for reception */
+	rxbd->status = BD_SC_EMPTY;
+	rxbd->length = size_to_expect;
+	rxbd->addr = datain;
+
+	txbd->status |= BD_I2C_TX_START;
+	if (flags & I2CF_STOP_COND)
+	{
+		txbd->status |= BD_SC_LAST | BD_SC_WRAP;
+		rxbd->status |= BD_SC_WRAP;
+	}
+
+	PRINTD(("[I2C] txbd: length=0x%04x status=0x%04x addr[0]=0x%02x addr[1]=0x%02x\n",
+		   txbd->length,
+		   txbd->status,
+		   txbd->addr[0],
+		   txbd->addr[1]));
+	PRINTD(("[I2C] rxbd: length=0x%04x status=0x%04x addr[0]=0x%02x addr[1]=0x%02x\n",
+		   rxbd->length,
+		   rxbd->status,
+		   rxbd->addr[0],
+		   rxbd->addr[1]));
+
+	/* advance state */
+	state->tx_buf += txbd->length;
+	state->tx_space -= txbd->length;
+	state->tx_idx++;
+	state->txbd = (void*)(txbd + 1);
+	state->rx_idx++;
+	state->rxbd = (void*)(rxbd + 1);
+
+	return 0;
+}
+
+
+static
+int i2c_doio(i2c_state_t *state)
+{
+	volatile immap_t *immap = (immap_t *)CFG_IMMR ;
+	volatile iic_t *iip;
+	volatile i2c8260_t *i2c	= (i2c8260_t *)&immap->im_i2c;
+	volatile I2C_BD *txbd, *rxbd;
+	int  j;
+        int  timeout;
+	uint dpaddr;
+
+	PRINTD(("[I2C] i2c_doio\n"));
+
+        timeout = TOUT_LOOP * 256;	/* arbitrarily long */
+
+	if (state->tx_idx <= 0 && state->rx_idx <= 0) {
+		PRINTD(("[I2C] No I/O is queued\n"));
+		return I2CERR_QUEUE_EMPTY;
+	}
+
+	dpaddr = *((unsigned short*)(&immap->im_dprambase[PROFF_I2C_BASE]));
+	iip = (iic_t *)&immap->im_dprambase[dpaddr];
+	iip->iic_rbptr = iip->iic_rbase;
+	iip->iic_tbptr = iip->iic_tbase;
+
+	/* Enable I2C */
+	PRINTD(("[I2C] Enabling I2C...\n"));
+	i2c->i2c_i2mod |= 0x01;
+
+	/* Begin transmission */
+	i2c->i2c_i2com |= 0x80;
+
+	/* Loop until transmit & receive completed */
+
+	txbd = ((I2C_BD*)state->txbd) - 1;
+	j = 0;
+	if (state->tx_idx > 0) {
+        	timeout = TOUT_LOOP * txbd->length;
+
+		PRINTD(("[I2C] Transmitting...(txbd=0x%08lx)\n", (ulong)txbd));
+		udelay(START_DELAY_US);	/* give it time to start */
+		while((txbd->status & BD_SC_READY) && (j++ < timeout)) {
+			udelay(DELAY_US);
+			if (ctrlc())
+				return (-1);
+			__asm__ __volatile__ ("eieio");
+		}
+	}
+
+	rxbd = ((I2C_BD*)state->rxbd) - 1;
+	j = 0;
+	if ((state->rx_idx > 0) && (j < timeout)) {
+        	timeout = TOUT_LOOP * rxbd->length;
+		PRINTD(("[I2C] Receiving...(rxbd=0x%08lx)\n", (ulong)rxbd));
+		udelay(START_DELAY_US);	/* give it time to start */
+		while((rxbd->status & BD_SC_EMPTY) && (j++ < timeout)) {
+			udelay(DELAY_US);
+			if (ctrlc())
+				return (-1);
+			__asm__ __volatile__ ("eieio");
+		}
+	}
+
+	/* Turn off I2C */
+	i2c->i2c_i2mod &= ~0x01;
+
+	if (state->err_cb != NULL) {
+		int n, i, b;
+
+		/*
+		 * if we have an error callback function, look at the
+		 * error bits in the bd status and pass them back
+		 */
+
+		if ((n = state->tx_idx) > 0) {
+			for (i = 0; i < n; i++) {
+				txbd = ((I2C_BD*)state->txbd) - (n - i);
+				if ((b = txbd->status & BD_I2C_TX_ERR) != 0)
+					(*state->err_cb)(I2CECB_TX_ERR|b, i);
+			}
+		}
+
+		if ((n = state->rx_idx) > 0) {
+			for (i = 0; i < n; i++) {
+				rxbd = ((I2C_BD*)state->rxbd) - (n - i);
+				if ((b = rxbd->status & BD_I2C_RX_ERR) != 0)
+					(*state->err_cb)(I2CECB_RX_ERR|b, i);
+			}
+		}
+
+		if (j >= timeout)
+			(*state->err_cb)(I2CECB_TIMEOUT, 0);
+	}
+
+	/* sort out errors and return appropriate good/error status */
+	if(j >= timeout)
+		return(I2CERR_TIMEOUT);
+	if((txbd->status & BD_I2C_TX_ERR) != 0)
+		return(I2CECB_TX_ERR | (txbd->status & I2CECB_TX_MASK));
+	if((rxbd->status & BD_I2C_RX_ERR) != 0)
+		return(I2CECB_RX_ERR | (rxbd->status & I2CECB_RX_MASK));
+
+	return(0);
+}
+
+static int had_tx_nak;
+
+static void
+i2c_test_callback(int flags, int xnum)
+{
+	if ((flags & I2CECB_TX_ERR) && (flags & I2CECB_TX_NAK))
+		had_tx_nak = 1;
+}
+
+int i2c_probe(uchar chip)
+{
+	i2c_state_t state;
+	int rc;
+	uchar buf[1];
+
+	i2c_newio(&state);
+
+	state.err_cb = i2c_test_callback;
+	had_tx_nak = 0;
+
+	rc = i2c_receive(&state, chip, 0, I2CF_START_COND|I2CF_STOP_COND, 1, buf);
+
+	if (rc != 0)
+		return (rc);
+
+	rc = i2c_doio(&state);
+
+	if ((rc != 0) && (rc != I2CERR_TIMEOUT))
+		return (rc);
+
+	return (had_tx_nak);
+}
+
+
+int
+i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+	i2c_state_t state;
+	uchar xaddr[4];
+	int rc;
+
+	xaddr[0] = (addr >> 24) & 0xFF;
+	xaddr[1] = (addr >> 16) & 0xFF;
+	xaddr[2] = (addr >>  8) & 0xFF;
+	xaddr[3] =  addr        & 0xFF;
+
+#ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW
+	 /*
+	  * EEPROM chips that implement "address overflow" are ones
+	  * like Catalyst 24WC04/08/16 which has 9/10/11 bits of address
+	  * and the extra bits end up in the "chip address" bit slots.
+	  * This makes a 24WC08 (1Kbyte) chip look like four 256 byte
+	  * chips.
+  	  *
+	  * Note that we consider the length of the address field to still
+	  * be one byte because the extra address bits are hidden in the
+	  * chip address.
+	  */
+	chip |= ((addr >> (alen * 8)) & CFG_I2C_EEPROM_ADDR_OVERFLOW);
+#endif
+
+	i2c_newio(&state);
+
+	rc = i2c_send(&state, chip, 0, I2CF_START_COND, alen, &xaddr[4-alen]);
+	if (rc != 0) {
+		printf("i2c_read: i2c_send failed (%d)\n", rc);
+		return 1;
+	}
+
+	rc = i2c_receive(&state, chip, 0, I2CF_STOP_COND, len, buffer);
+	if (rc != 0) {
+		printf("i2c_read: i2c_receive failed (%d)\n", rc);
+		return 1;
+	}
+
+	rc = i2c_doio(&state);
+	if (rc != 0) {
+		printf("i2c_read: i2c_doio failed (%d)\n", rc);
+		return 1;
+	}
+	return 0;
+}
+
+int
+i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+	i2c_state_t state;
+	uchar xaddr[4];
+	int rc;
+
+	xaddr[0] = (addr >> 24) & 0xFF;
+	xaddr[1] = (addr >> 16) & 0xFF;
+	xaddr[2] = (addr >>  8) & 0xFF;
+	xaddr[3] =  addr        & 0xFF;
+
+#ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW
+	 /*
+	  * EEPROM chips that implement "address overflow" are ones
+	  * like Catalyst 24WC04/08/16 which has 9/10/11 bits of address
+	  * and the extra bits end up in the "chip address" bit slots.
+	  * This makes a 24WC08 (1Kbyte) chip look like four 256 byte
+	  * chips.
+  	  *
+	  * Note that we consider the length of the address field to still
+	  * be one byte because the extra address bits are hidden in the
+	  * chip address.
+	  */
+	chip |= ((addr >> (alen * 8)) & CFG_I2C_EEPROM_ADDR_OVERFLOW);
+#endif
+
+	i2c_newio(&state);
+
+	rc = i2c_send(&state, chip, 0, I2CF_START_COND, alen, &xaddr[4-alen]);
+	if (rc != 0) {
+		printf("i2c_write: first i2c_send failed (%d)\n", rc);
+		return 1;
+	}
+
+	rc = i2c_send(&state, 0, 0, I2CF_STOP_COND, len, buffer);
+	if (rc != 0) {
+		printf("i2c_write: second i2c_send failed (%d)\n", rc);
+		return 1;
+	}
+
+	rc = i2c_doio(&state);
+	if (rc != 0) {
+		printf("i2c_write: i2c_doio failed (%d)\n", rc);
+		return 1;
+	}
+	return 0;
+}
+
+uchar
+i2c_reg_read(uchar chip, uchar reg)
+{
+	char buf;
+
+	i2c_read(chip, reg, 1, &buf, 1);
+
+	return (buf);
+}
+
+void
+i2c_reg_write(uchar chip, uchar reg, uchar val)
+{
+	i2c_write(chip, reg, 1, &val, 1);
+}
+
+#endif	/* CONFIG_HARD_I2C */