/*
 * i2c driver for Freescale mx31
 *
 * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.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/arch/mx31.h>
#include <asm/arch/mx31-regs.h>

#define IADR    0x00
#define IFDR    0x04
#define I2CR    0x08
#define I2SR    0x0c
#define I2DR    0x10

#define I2CR_IEN        (1 << 7)
#define I2CR_IIEN       (1 << 6)
#define I2CR_MSTA       (1 << 5)
#define I2CR_MTX        (1 << 4)
#define I2CR_TX_NO_AK   (1 << 3)
#define I2CR_RSTA       (1 << 2)

#define I2SR_ICF        (1 << 7)
#define I2SR_IBB        (1 << 5)
#define I2SR_IIF        (1 << 1)
#define I2SR_RX_NO_AK   (1 << 0)

#ifdef CONFIG_SYS_I2C_MX31_PORT1
#define I2C_BASE        0x43f80000
#define I2C_CLK_OFFSET  26
#elif defined (CONFIG_SYS_I2C_MX31_PORT2)
#define I2C_BASE        0x43f98000
#define I2C_CLK_OFFSET  28
#elif defined (CONFIG_SYS_I2C_MX31_PORT3)
#define I2C_BASE        0x43f84000
#define I2C_CLK_OFFSET  30
#else
#error "define CONFIG_SYS_I2C_MX31_PORTx to use the mx31 I2C driver"
#endif

#ifdef DEBUG
#define DPRINTF(args...)  printf(args)
#else
#define DPRINTF(args...)
#endif

static u16 div[] = { 30, 32, 36, 42, 48, 52, 60, 72, 80, 88, 104, 128, 144,
                     160, 192, 240, 288, 320, 384, 480, 576, 640, 768, 960,
                     1152, 1280, 1536, 1920, 2304, 2560, 3072, 3840};

void i2c_init(int speed, int unused)
{
        int freq = mx31_get_ipg_clk();
        int i;

        /* start the required I2C clock */
        __REG(CCM_CGR0) = __REG(CCM_CGR0) | (3 << I2C_CLK_OFFSET);

        for (i = 0; i < 0x1f; i++)
                if (freq / div[i] <= speed)
                        break;

        DPRINTF("%s: speed: %d\n",__FUNCTION__, speed);

        __REG16(I2C_BASE + I2CR) = 0; /* Reset module */
        __REG16(I2C_BASE + IFDR) = i;
        __REG16(I2C_BASE + I2CR) = I2CR_IEN;
        __REG16(I2C_BASE + I2SR) = 0;
}

static int wait_busy(void)
{
        int timeout = 10000;

        while (!(__REG16(I2C_BASE + I2SR) & I2SR_IIF) && --timeout)
                udelay(1);
        __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */

        return timeout;
}

static int tx_byte(u8 byte)
{
        __REG16(I2C_BASE + I2DR) = byte;

        if (!wait_busy() || __REG16(I2C_BASE + I2SR) & I2SR_RX_NO_AK)
                return -1;
        return 0;
}

static int rx_byte(void)
{
        if (!wait_busy())
                return -1;

        return __REG16(I2C_BASE + I2DR);
}

int i2c_probe(uchar chip)
{
        int ret;

        __REG16(I2C_BASE + I2CR) = 0; /* Reset module */
        __REG16(I2C_BASE + I2CR) = I2CR_IEN;

        __REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | I2CR_MTX;
        ret = tx_byte(chip << 1);
        __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MTX;

        return ret;
}

static int i2c_addr(uchar chip, uint addr, int alen)
{
        __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */
        __REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | I2CR_MTX;

        if (tx_byte(chip << 1))
                return -1;

        while (alen--)
                if (tx_byte((addr >> (alen * 8)) & 0xff))
                        return -1;
        return 0;
}

int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
{
        int timeout = 10000;
        int ret;

        DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len);

        if (i2c_addr(chip, addr, alen)) {
                printf("i2c_addr failed\n");
                return -1;
        }

        __REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | I2CR_MTX | I2CR_RSTA;

        if (tx_byte(chip << 1 | 1))
                return -1;

        __REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | ((len == 1) ? I2CR_TX_NO_AK : 0);

        ret = __REG16(I2C_BASE + I2DR);

        while (len--) {
                if ((ret = rx_byte()) < 0)
                        return -1;
                *buf++ = ret;
                if (len <= 1)
                        __REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | I2CR_TX_NO_AK;
        }

        wait_busy();

        __REG16(I2C_BASE + I2CR) = I2CR_IEN;

        while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout)
                udelay(1);

        return 0;
}

int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
{
        int timeout = 10000;
        DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len);

        if (i2c_addr(chip, addr, alen))
                return -1;

        while (len--)
                if (tx_byte(*buf++))
                        return -1;

        __REG16(I2C_BASE + I2CR) = I2CR_IEN;

        while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout)
                udelay(1);

        return 0;
}

#endif /* CONFIG_HARD_I2C */