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  • /*
     * Copyright 2013 Broadcom Corporation.
     *
     * SPDX-License-Identifier:      GPL-2.0+
     */
    
    #include <common.h>
    #include <asm/io.h>
    #include <asm/errno.h>
    #include <asm/arch/sysmap.h>
    #include <asm/kona-common/clk.h>
    #include <i2c.h>
    
    /* Hardware register offsets and field defintions */
    #define CS_OFFSET				0x00000020
    #define CS_ACK_SHIFT				3
    #define CS_ACK_MASK				0x00000008
    #define CS_ACK_CMD_GEN_START			0x00000000
    #define CS_ACK_CMD_GEN_RESTART			0x00000001
    #define CS_CMD_SHIFT				1
    #define CS_CMD_CMD_NO_ACTION			0x00000000
    #define CS_CMD_CMD_START_RESTART		0x00000001
    #define CS_CMD_CMD_STOP				0x00000002
    #define CS_EN_SHIFT				0
    #define CS_EN_CMD_ENABLE_BSC			0x00000001
    
    #define TIM_OFFSET				0x00000024
    #define TIM_PRESCALE_SHIFT			6
    #define TIM_P_SHIFT				3
    #define TIM_NO_DIV_SHIFT			2
    #define TIM_DIV_SHIFT				0
    
    #define DAT_OFFSET				0x00000028
    
    #define TOUT_OFFSET				0x0000002c
    
    #define TXFCR_OFFSET				0x0000003c
    #define TXFCR_FIFO_FLUSH_MASK			0x00000080
    #define TXFCR_FIFO_EN_MASK			0x00000040
    
    #define IER_OFFSET				0x00000044
    #define IER_READ_COMPLETE_INT_MASK		0x00000010
    #define IER_I2C_INT_EN_MASK			0x00000008
    #define IER_FIFO_INT_EN_MASK			0x00000002
    #define IER_NOACK_EN_MASK			0x00000001
    
    #define ISR_OFFSET				0x00000048
    #define ISR_RESERVED_MASK			0xffffff60
    #define ISR_CMDBUSY_MASK			0x00000080
    #define ISR_READ_COMPLETE_MASK			0x00000010
    #define ISR_SES_DONE_MASK			0x00000008
    #define ISR_ERR_MASK				0x00000004
    #define ISR_TXFIFOEMPTY_MASK			0x00000002
    #define ISR_NOACK_MASK				0x00000001
    
    #define CLKEN_OFFSET				0x0000004c
    #define CLKEN_AUTOSENSE_OFF_MASK		0x00000080
    #define CLKEN_M_SHIFT				4
    #define CLKEN_N_SHIFT				1
    #define CLKEN_CLKEN_MASK			0x00000001
    
    #define FIFO_STATUS_OFFSET			0x00000054
    #define FIFO_STATUS_RXFIFO_EMPTY_MASK		0x00000004
    #define FIFO_STATUS_TXFIFO_EMPTY_MASK		0x00000010
    
    #define HSTIM_OFFSET				0x00000058
    #define HSTIM_HS_MODE_MASK			0x00008000
    #define HSTIM_HS_HOLD_SHIFT			10
    #define HSTIM_HS_HIGH_PHASE_SHIFT		5
    #define HSTIM_HS_SETUP_SHIFT			0
    
    #define PADCTL_OFFSET				0x0000005c
    #define PADCTL_PAD_OUT_EN_MASK			0x00000004
    
    #define RXFCR_OFFSET				0x00000068
    #define RXFCR_NACK_EN_SHIFT			7
    #define RXFCR_READ_COUNT_SHIFT			0
    #define RXFIFORDOUT_OFFSET			0x0000006c
    
    /* Locally used constants */
    #define MAX_RX_FIFO_SIZE		64U	/* bytes */
    #define MAX_TX_FIFO_SIZE		64U	/* bytes */
    
    #define I2C_TIMEOUT			100000	/* usecs */
    
    #define WAIT_INT_CHK			100	/* usecs */
    #if I2C_TIMEOUT % WAIT_INT_CHK
    #error I2C_TIMEOUT must be a multiple of WAIT_INT_CHK
    #endif
    
    /* Operations that can be commanded to the controller */
    enum bcm_kona_cmd_t {
    	BCM_CMD_NOACTION = 0,
    	BCM_CMD_START,
    	BCM_CMD_RESTART,
    	BCM_CMD_STOP,
    };
    
    enum bus_speed_index {
    	BCM_SPD_100K = 0,
    	BCM_SPD_400K,
    	BCM_SPD_1MHZ,
    };
    
    /* Internal divider settings for standard mode, fast mode and fast mode plus */
    struct bus_speed_cfg {
    	uint8_t time_m;		/* Number of cycles for setup time */
    	uint8_t time_n;		/* Number of cycles for hold time */
    	uint8_t prescale;	/* Prescale divider */
    	uint8_t time_p;		/* Timing coefficient */
    	uint8_t no_div;		/* Disable clock divider */
    	uint8_t time_div;	/* Post-prescale divider */
    };
    
    static const struct bus_speed_cfg std_cfg_table[] = {
    	[BCM_SPD_100K] = {0x01, 0x01, 0x03, 0x06, 0x00, 0x02},
    	[BCM_SPD_400K] = {0x05, 0x01, 0x03, 0x05, 0x01, 0x02},
    	[BCM_SPD_1MHZ] = {0x01, 0x01, 0x03, 0x01, 0x01, 0x03},
    };
    
    struct bcm_kona_i2c_dev {
    	void *base;
    	uint speed;
    	const struct bus_speed_cfg *std_cfg;
    };
    
    /* Keep these two defines in sync */
    #define DEF_SPD 100000
    #define DEF_SPD_ENUM BCM_SPD_100K
    
    #define DEF_DEVICE(num) \
    {(void *)CONFIG_SYS_I2C_BASE##num, DEF_SPD, &std_cfg_table[DEF_SPD_ENUM]}
    
    static struct bcm_kona_i2c_dev g_i2c_devs[CONFIG_SYS_MAX_I2C_BUS] = {
    #ifdef CONFIG_SYS_I2C_BASE0
    	DEF_DEVICE(0),
    #endif
    #ifdef CONFIG_SYS_I2C_BASE1
    	DEF_DEVICE(1),
    #endif
    #ifdef CONFIG_SYS_I2C_BASE2
    	DEF_DEVICE(2),
    #endif
    #ifdef CONFIG_SYS_I2C_BASE3
    	DEF_DEVICE(3),
    #endif
    #ifdef CONFIG_SYS_I2C_BASE4
    	DEF_DEVICE(4),
    #endif
    #ifdef CONFIG_SYS_I2C_BASE5
    	DEF_DEVICE(5),
    #endif
    };
    
    #define I2C_M_TEN	0x0010	/* ten bit address */
    #define I2C_M_RD	0x0001	/* read data */
    #define I2C_M_NOSTART	0x4000	/* no restart between msgs */
    
    
    struct kona_i2c_msg {
    
    	uint16_t addr;
    	uint16_t flags;
    	uint16_t len;
    	uint8_t *buf;
    };
    
    static void bcm_kona_i2c_send_cmd_to_ctrl(struct bcm_kona_i2c_dev *dev,
    					  enum bcm_kona_cmd_t cmd)
    {
    	debug("%s, %d\n", __func__, cmd);
    
    	switch (cmd) {
    	case BCM_CMD_NOACTION:
    		writel((CS_CMD_CMD_NO_ACTION << CS_CMD_SHIFT) |
    		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
    		       dev->base + CS_OFFSET);
    		break;
    
    	case BCM_CMD_START:
    		writel((CS_ACK_CMD_GEN_START << CS_ACK_SHIFT) |
    		       (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
    		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
    		       dev->base + CS_OFFSET);
    		break;
    
    	case BCM_CMD_RESTART:
    		writel((CS_ACK_CMD_GEN_RESTART << CS_ACK_SHIFT) |
    		       (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
    		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
    		       dev->base + CS_OFFSET);
    		break;
    
    	case BCM_CMD_STOP:
    		writel((CS_CMD_CMD_STOP << CS_CMD_SHIFT) |
    		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
    		       dev->base + CS_OFFSET);
    		break;
    
    	default:
    		printf("Unknown command %d\n", cmd);
    	}
    }
    
    static void bcm_kona_i2c_enable_clock(struct bcm_kona_i2c_dev *dev)
    {
    	writel(readl(dev->base + CLKEN_OFFSET) | CLKEN_CLKEN_MASK,
    	       dev->base + CLKEN_OFFSET);
    }
    
    static void bcm_kona_i2c_disable_clock(struct bcm_kona_i2c_dev *dev)
    {
    	writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_CLKEN_MASK,
    	       dev->base + CLKEN_OFFSET);
    }
    
    /* Wait until at least one of the mask bit(s) are set */
    static unsigned long wait_for_int_timeout(struct bcm_kona_i2c_dev *dev,
    					  unsigned long time_left,
    					  uint32_t mask)
    {
    	uint32_t status;
    
    	while (time_left) {
    		status = readl(dev->base + ISR_OFFSET);
    
    		if ((status & ~ISR_RESERVED_MASK) == 0) {
    			debug("Bogus I2C interrupt 0x%x\n", status);
    			continue;
    		}
    
    		/* Must flush the TX FIFO when NAK detected */
    		if (status & ISR_NOACK_MASK)
    			writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
    			       dev->base + TXFCR_OFFSET);
    
    		writel(status & ~ISR_RESERVED_MASK, dev->base + ISR_OFFSET);
    
    		if (status & mask) {
    			/* We are done since one of the mask bits are set */
    			return time_left;
    		}
    		udelay(WAIT_INT_CHK);
    		time_left -= WAIT_INT_CHK;
    	}
    	return 0;
    }
    
    /* Send command to I2C bus */
    static int bcm_kona_send_i2c_cmd(struct bcm_kona_i2c_dev *dev,
    				 enum bcm_kona_cmd_t cmd)
    {
    	int rc = 0;
    	unsigned long time_left = I2C_TIMEOUT;
    
    	/* Send the command */
    	bcm_kona_i2c_send_cmd_to_ctrl(dev, cmd);
    
    	/* Wait for transaction to finish or timeout */
    	time_left = wait_for_int_timeout(dev, time_left, IER_I2C_INT_EN_MASK);
    
    	if (!time_left) {
    		printf("controller timed out\n");
    		rc = -ETIMEDOUT;
    	}
    
    	/* Clear command */
    	bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
    
    	return rc;
    }
    
    /* Read a single RX FIFO worth of data from the i2c bus */
    static int bcm_kona_i2c_read_fifo_single(struct bcm_kona_i2c_dev *dev,
    					 uint8_t *buf, unsigned int len,
    					 unsigned int last_byte_nak)
    {
    	unsigned long time_left = I2C_TIMEOUT;
    
    	/* Start the RX FIFO */
    	writel((last_byte_nak << RXFCR_NACK_EN_SHIFT) |
    	       (len << RXFCR_READ_COUNT_SHIFT), dev->base + RXFCR_OFFSET);
    
    	/* Wait for FIFO read to complete */
    	time_left =
    	    wait_for_int_timeout(dev, time_left, IER_READ_COMPLETE_INT_MASK);
    
    	if (!time_left) {
    		printf("RX FIFO time out\n");
    		return -EREMOTEIO;
    	}
    
    	/* Read data from FIFO */
    	for (; len > 0; len--, buf++)
    		*buf = readl(dev->base + RXFIFORDOUT_OFFSET);
    
    	return 0;
    }
    
    /* Read any amount of data using the RX FIFO from the i2c bus */
    static int bcm_kona_i2c_read_fifo(struct bcm_kona_i2c_dev *dev,
    
    				  struct kona_i2c_msg *msg)
    
    {
    	unsigned int bytes_to_read = MAX_RX_FIFO_SIZE;
    	unsigned int last_byte_nak = 0;
    	unsigned int bytes_read = 0;
    	int rc;
    
    	uint8_t *tmp_buf = msg->buf;
    
    	while (bytes_read < msg->len) {
    		if (msg->len - bytes_read <= MAX_RX_FIFO_SIZE) {
    			last_byte_nak = 1;	/* NAK last byte of transfer */
    			bytes_to_read = msg->len - bytes_read;
    		}
    
    		rc = bcm_kona_i2c_read_fifo_single(dev, tmp_buf, bytes_to_read,
    						   last_byte_nak);
    		if (rc < 0)
    			return -EREMOTEIO;
    
    		bytes_read += bytes_to_read;
    		tmp_buf += bytes_to_read;
    	}
    
    	return 0;
    }
    
    /* Write a single byte of data to the i2c bus */
    static int bcm_kona_i2c_write_byte(struct bcm_kona_i2c_dev *dev, uint8_t data,
    				   unsigned int nak_expected)
    {
    	unsigned long time_left = I2C_TIMEOUT;
    	unsigned int nak_received;
    
    	/* Clear pending session done interrupt */
    	writel(ISR_SES_DONE_MASK, dev->base + ISR_OFFSET);
    
    	/* Send one byte of data */
    	writel(data, dev->base + DAT_OFFSET);
    
    	time_left = wait_for_int_timeout(dev, time_left, IER_I2C_INT_EN_MASK);
    
    	if (!time_left) {
    		debug("controller timed out\n");
    		return -ETIMEDOUT;
    	}
    
    	nak_received = readl(dev->base + CS_OFFSET) & CS_ACK_MASK ? 1 : 0;
    
    	if (nak_received ^ nak_expected) {
    		debug("unexpected NAK/ACK\n");
    		return -EREMOTEIO;
    	}
    
    	return 0;
    }
    
    /* Write a single TX FIFO worth of data to the i2c bus */
    static int bcm_kona_i2c_write_fifo_single(struct bcm_kona_i2c_dev *dev,
    					  uint8_t *buf, unsigned int len)
    {
    	int k;
    	unsigned long time_left = I2C_TIMEOUT;
    	unsigned int fifo_status;
    
    	/* Write data into FIFO */
    	for (k = 0; k < len; k++)
    		writel(buf[k], (dev->base + DAT_OFFSET));
    
    	/* Wait for FIFO to empty */
    	do {
    		time_left =
    		    wait_for_int_timeout(dev, time_left,
    					 (IER_FIFO_INT_EN_MASK |
    					  IER_NOACK_EN_MASK));
    		fifo_status = readl(dev->base + FIFO_STATUS_OFFSET);
    	} while (time_left && !(fifo_status & FIFO_STATUS_TXFIFO_EMPTY_MASK));
    
    	/* Check if there was a NAK */
    	if (readl(dev->base + CS_OFFSET) & CS_ACK_MASK) {
    		printf("unexpected NAK\n");
    		return -EREMOTEIO;
    	}
    
    	/* Check if a timeout occured */
    	if (!time_left) {
    		printf("completion timed out\n");
    		return -EREMOTEIO;
    	}
    
    	return 0;
    }
    
    /* Write any amount of data using TX FIFO to the i2c bus */
    static int bcm_kona_i2c_write_fifo(struct bcm_kona_i2c_dev *dev,
    
    				   struct kona_i2c_msg *msg)
    
    {
    	unsigned int bytes_to_write = MAX_TX_FIFO_SIZE;
    	unsigned int bytes_written = 0;
    	int rc;
    
    	uint8_t *tmp_buf = msg->buf;
    
    	while (bytes_written < msg->len) {
    		if (msg->len - bytes_written <= MAX_TX_FIFO_SIZE)
    			bytes_to_write = msg->len - bytes_written;
    
    		rc = bcm_kona_i2c_write_fifo_single(dev, tmp_buf,
    						    bytes_to_write);
    		if (rc < 0)
    			return -EREMOTEIO;
    
    		bytes_written += bytes_to_write;
    		tmp_buf += bytes_to_write;
    	}
    
    	return 0;
    }
    
    /* Send i2c address */
    static int bcm_kona_i2c_do_addr(struct bcm_kona_i2c_dev *dev,
    
    				struct kona_i2c_msg *msg)
    
    {
    	unsigned char addr;
    
    	if (msg->flags & I2C_M_TEN) {
    		/* First byte is 11110XX0 where XX is upper 2 bits */
    		addr = 0xf0 | ((msg->addr & 0x300) >> 7);
    		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
    			return -EREMOTEIO;
    
    		/* Second byte is the remaining 8 bits */
    		addr = msg->addr & 0xff;
    		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
    			return -EREMOTEIO;
    
    		if (msg->flags & I2C_M_RD) {
    			/* For read, send restart command */
    			if (bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART) < 0)
    				return -EREMOTEIO;
    
    			/* Then re-send the first byte with the read bit set */
    			addr = 0xf0 | ((msg->addr & 0x300) >> 7) | 0x01;
    			if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
    				return -EREMOTEIO;
    		}
    	} else {
    		addr = msg->addr << 1;
    
    		if (msg->flags & I2C_M_RD)
    			addr |= 1;
    
    		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
    			return -EREMOTEIO;
    	}
    
    	return 0;
    }
    
    static void bcm_kona_i2c_enable_autosense(struct bcm_kona_i2c_dev *dev)
    {
    	writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_AUTOSENSE_OFF_MASK,
    	       dev->base + CLKEN_OFFSET);
    }
    
    static void bcm_kona_i2c_config_timing(struct bcm_kona_i2c_dev *dev)
    {
    	writel(readl(dev->base + HSTIM_OFFSET) & ~HSTIM_HS_MODE_MASK,
    	       dev->base + HSTIM_OFFSET);
    
    	writel((dev->std_cfg->prescale << TIM_PRESCALE_SHIFT) |
    	       (dev->std_cfg->time_p << TIM_P_SHIFT) |
    	       (dev->std_cfg->no_div << TIM_NO_DIV_SHIFT) |
    	       (dev->std_cfg->time_div << TIM_DIV_SHIFT),
    	       dev->base + TIM_OFFSET);
    
    	writel((dev->std_cfg->time_m << CLKEN_M_SHIFT) |
    	       (dev->std_cfg->time_n << CLKEN_N_SHIFT) |
    	       CLKEN_CLKEN_MASK, dev->base + CLKEN_OFFSET);
    }
    
    /* Master transfer function */
    static int bcm_kona_i2c_xfer(struct bcm_kona_i2c_dev *dev,
    
    			     struct kona_i2c_msg msgs[], int num)
    
    	struct kona_i2c_msg *pmsg;
    
    	int rc = 0;
    	int i;
    
    	/* Enable pad output */
    	writel(0, dev->base + PADCTL_OFFSET);
    
    	/* Enable internal clocks */
    	bcm_kona_i2c_enable_clock(dev);
    
    	/* Send start command */
    	rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_START);
    	if (rc < 0) {
    		printf("Start command failed rc = %d\n", rc);
    		goto xfer_disable_pad;
    	}
    
    	/* Loop through all messages */
    	for (i = 0; i < num; i++) {
    		pmsg = &msgs[i];
    
    		/* Send restart for subsequent messages */
    		if ((i != 0) && ((pmsg->flags & I2C_M_NOSTART) == 0)) {
    			rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART);
    			if (rc < 0) {
    				printf("restart cmd failed rc = %d\n", rc);
    				goto xfer_send_stop;
    			}
    		}
    
    		/* Send slave address */
    		if (!(pmsg->flags & I2C_M_NOSTART)) {
    			rc = bcm_kona_i2c_do_addr(dev, pmsg);
    			if (rc < 0) {
    				debug("NAK from addr %2.2x msg#%d rc = %d\n",
    				      pmsg->addr, i, rc);
    				goto xfer_send_stop;
    			}
    		}
    
    		/* Perform data transfer */
    		if (pmsg->flags & I2C_M_RD) {
    			rc = bcm_kona_i2c_read_fifo(dev, pmsg);
    			if (rc < 0) {
    				printf("read failure\n");
    				goto xfer_send_stop;
    			}
    		} else {
    			rc = bcm_kona_i2c_write_fifo(dev, pmsg);
    			if (rc < 0) {
    				printf("write failure");
    				goto xfer_send_stop;
    			}
    		}
    	}
    
    	rc = num;
    
    xfer_send_stop:
    	/* Send a STOP command */
    	bcm_kona_send_i2c_cmd(dev, BCM_CMD_STOP);
    
    xfer_disable_pad:
    	/* Disable pad output */
    	writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
    
    	/* Stop internal clock */
    	bcm_kona_i2c_disable_clock(dev);
    
    	return rc;
    }
    
    static uint bcm_kona_i2c_assign_bus_speed(struct bcm_kona_i2c_dev *dev,
    					  uint speed)
    {
    	switch (speed) {
    	case 100000:
    		dev->std_cfg = &std_cfg_table[BCM_SPD_100K];
    		break;
    	case 400000:
    		dev->std_cfg = &std_cfg_table[BCM_SPD_400K];
    		break;
    	case 1000000:
    		dev->std_cfg = &std_cfg_table[BCM_SPD_1MHZ];
    		break;
    	default:
    		printf("%d hz bus speed not supported\n", speed);
    		return -EINVAL;
    	}
    	dev->speed = speed;
    	return 0;
    }
    
    static void bcm_kona_i2c_init(struct bcm_kona_i2c_dev *dev)
    {
    	/* Parse bus speed */
    	bcm_kona_i2c_assign_bus_speed(dev, dev->speed);
    
    	/* Enable internal clocks */
    	bcm_kona_i2c_enable_clock(dev);
    
    	/* Configure internal dividers */
    	bcm_kona_i2c_config_timing(dev);
    
    	/* Disable timeout */
    	writel(0, dev->base + TOUT_OFFSET);
    
    	/* Enable autosense */
    	bcm_kona_i2c_enable_autosense(dev);
    
    	/* Enable TX FIFO */
    	writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
    	       dev->base + TXFCR_OFFSET);
    
    	/* Mask all interrupts */
    	writel(0, dev->base + IER_OFFSET);
    
    	/* Clear all pending interrupts */
    	writel(ISR_CMDBUSY_MASK |
    	       ISR_READ_COMPLETE_MASK |
    	       ISR_SES_DONE_MASK |
    	       ISR_ERR_MASK |
    	       ISR_TXFIFOEMPTY_MASK | ISR_NOACK_MASK, dev->base + ISR_OFFSET);
    
    	/* Enable the controller but leave it idle */
    	bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
    
    	/* Disable pad output */
    	writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
    }
    
    /*
     * uboot layer
     */
    struct bcm_kona_i2c_dev *kona_get_dev(struct i2c_adapter *adap)
    {
    	return &g_i2c_devs[adap->hwadapnr];
    }
    
    static void kona_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
    {
    	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
    
    	if (clk_bsc_enable(dev->base))
    		return;
    
    	bcm_kona_i2c_init(dev);
    }
    
    static int kona_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
    			 int alen, uchar *buffer, int len)
    {
    	/* msg[0] writes the addr, msg[1] reads the data */
    
    	struct kona_i2c_msg msg[2];
    
    	unsigned char msgbuf0[64];
    	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
    
    	msg[0].addr = chip;
    	msg[0].flags = 0;
    	msg[0].len = 1;
    	msg[0].buf = msgbuf0;	/* msgbuf0 contains incrementing reg addr */
    
    	msg[1].addr = chip;
    	msg[1].flags = I2C_M_RD;
    	/* msg[1].buf dest ptr increments each read */
    
    	msgbuf0[0] = (unsigned char)addr;
    	msg[1].buf = buffer;
    	msg[1].len = len;
    	if (bcm_kona_i2c_xfer(dev, msg, 2) < 0) {
    		/* Sending 2 i2c messages */
    		kona_i2c_init(adap, adap->speed, adap->slaveaddr);
    		debug("I2C read: I/O error\n");
    		return -EIO;
    	}
    	return 0;
    }
    
    static int kona_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
    			  int alen, uchar *buffer, int len)
    {
    
    	struct kona_i2c_msg msg[1];
    
    	unsigned char msgbuf0[64];
    	unsigned int i;
    	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
    
    	msg[0].addr = chip;
    	msg[0].flags = 0;
    	msg[0].len = 2;		/* addr byte plus data */
    	msg[0].buf = msgbuf0;
    
    	for (i = 0; i < len; i++) {
    		msgbuf0[0] = addr++;
    		msgbuf0[1] = buffer[i];
    		if (bcm_kona_i2c_xfer(dev, msg, 1) < 0) {
    			kona_i2c_init(adap, adap->speed, adap->slaveaddr);
    			debug("I2C write: I/O error\n");
    			return -EIO;
    		}
    	}
    	return 0;
    }
    
    static int kona_i2c_probe(struct i2c_adapter *adap, uchar chip)
    {
    	uchar tmp;
    
    	/*
    	 * read addr 0x0 of the given chip.
    	 */
    	return kona_i2c_read(adap, chip, 0x0, 1, &tmp, 1);
    }
    
    static uint kona_i2c_set_bus_speed(struct i2c_adapter *adap, uint speed)
    {
    	struct bcm_kona_i2c_dev *dev = kona_get_dev(adap);
    	return bcm_kona_i2c_assign_bus_speed(dev, speed);
    }
    
    /*
     * Register kona i2c adapters. Keep the order below so
     * that the bus number matches the adapter number.
     */
    #define DEF_ADAPTER(num) \
    U_BOOT_I2C_ADAP_COMPLETE(kona##num, kona_i2c_init, kona_i2c_probe, \
    			 kona_i2c_read, kona_i2c_write, \
    			 kona_i2c_set_bus_speed, DEF_SPD, 0x00, num)
    
    #ifdef CONFIG_SYS_I2C_BASE0
    	DEF_ADAPTER(0)
    #endif
    #ifdef CONFIG_SYS_I2C_BASE1
    	DEF_ADAPTER(1)
    #endif
    #ifdef CONFIG_SYS_I2C_BASE2
    	DEF_ADAPTER(2)
    #endif
    #ifdef CONFIG_SYS_I2C_BASE3
    	DEF_ADAPTER(3)
    #endif
    #ifdef CONFIG_SYS_I2C_BASE4
    	DEF_ADAPTER(4)
    #endif
    #ifdef CONFIG_SYS_I2C_BASE5
    	DEF_ADAPTER(5)
    #endif