/*
 * (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>
 *
 * 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
 *
 * Back ported to the 8xx platform (from the 8260 platform) by
 * Murray.Jensen@cmst.csiro.au, 27-Jan-01.
 */

/* FIXME: this file is PXA255 specific! What about other XScales? */

#include <common.h>

#ifdef CONFIG_HARD_I2C

/*
 *      - CONFIG_SYS_I2C_SPEED
 *      - I2C_PXA_SLAVE_ADDR
 */

#include <asm/arch/hardware.h>
#include <asm/arch/pxa-regs.h>
#include <i2c.h>

/*#define       DEBUG_I2C       1       /###* activate local debugging output  */
#define I2C_PXA_SLAVE_ADDR      0x1     /* slave pxa unit address           */

#if (CONFIG_SYS_I2C_SPEED == 400000)
#define I2C_ICR_INIT    (ICR_FM | ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
#else
#define I2C_ICR_INIT    (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
#endif

#define I2C_ISR_INIT            0x7FF

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


/* Shall the current transfer have a start/stop condition? */
#define I2C_COND_NORMAL         0
#define I2C_COND_START          1
#define I2C_COND_STOP           2

/* Shall the current transfer be ack/nacked or being waited for it? */
#define I2C_ACKNAK_WAITACK      1
#define I2C_ACKNAK_SENDACK      2
#define I2C_ACKNAK_SENDNAK      4

/* Specify who shall transfer the data (master or slave) */
#define I2C_READ                0
#define I2C_WRITE               1

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


/**
 * i2c_pxa_reset: - reset the host controller
 *
 */

static void i2c_reset( void )
{
        ICR &= ~ICR_IUE;                /* disable unit */
        ICR |= ICR_UR;                  /* reset the unit */
        udelay(100);
        ICR &= ~ICR_IUE;                /* disable unit */
#ifdef CONFIG_CPU_MONAHANS
        CKENB |= (CKENB_4_I2C); /*  | CKENB_1_PWM1 | CKENB_0_PWM0); */
#else /* CONFIG_CPU_MONAHANS */
        CKEN |= CKEN14_I2C;             /* set the global I2C clock on */
#endif
        ISAR = I2C_PXA_SLAVE_ADDR;      /* set our slave address */
        ICR = I2C_ICR_INIT;             /* set control register values */
        ISR = I2C_ISR_INIT;             /* set clear interrupt bits */
        ICR |= ICR_IUE;                 /* 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 = 10000;

        while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){
                udelay( 10 );
                if( timeout-- < 0 ) return 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 */
                ICR &= ~ICR_START;
                ICR &= ~ICR_STOP;
                IDBR = msg->data;
                if (msg->condition == I2C_COND_START)     ICR |=  ICR_START;
                if (msg->condition == I2C_COND_STOP)      ICR |=  ICR_STOP;
                if (msg->acknack   == I2C_ACKNAK_SENDNAK) ICR |=  ICR_ACKNAK;
                if (msg->acknack   == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
                ICR &= ~ICR_ALDIE;
                ICR |= ICR_TB;

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

                /* clear 'transmit empty' state */
                ISR |= ISR_ITE;

                /* 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 */
                ICR &= ~ICR_START;
                ICR &= ~ICR_STOP;
                if (msg->condition == I2C_COND_START)     ICR |= ICR_START;
                if (msg->condition == I2C_COND_STOP)      ICR |= ICR_STOP;
                if (msg->acknack   == I2C_ACKNAK_SENDNAK) ICR |=  ICR_ACKNAK;
                if (msg->acknack   == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
                ICR &= ~ICR_ALDIE;
                ICR |= ICR_TB;

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

                msg->data = IDBR;

                /* clear 'receive empty' state */
                ISR |= ISR_IRF;

                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",ISR));
                i2c_reset();
                return ret;

}

/* ------------------------------------------------------------------------ */
/* API Functions                                                            */
/* ------------------------------------------------------------------------ */

void i2c_init(int speed, int slaveaddr)
{
#ifdef CONFIG_SYS_I2C_INIT_BOARD
        /* 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.                  */
        i2c_init_board();
#endif
}


/**
 * 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 */
        int ret;

        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 ((ret=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 ((ret=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 ((ret=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 ((ret=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 */