/*
 * SPI interface driver for the DM320 SoC
 *
 * Copyright (C) 2007 shirour <mrobefan@gmail.com>
 * Copyright (C) 2007 Catalin Patulea <cat@vv.carleton.ca>
 *
 *  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  SOFTWARE  IS PROVIDED   ``AS IS'' AND   ANY EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO EVENT  SHALL   THE AUTHOR  BE  LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS OR SERVICES; LOSS OF
 *  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  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.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include "kernel.h"
#include "system.h"
#include "spi.h"

#define GIO_TS_ENABLE  (1<<2)
#define GIO_RTC_ENABLE (1<<12)
#define GIO_BL_ENABLE  (1<<13)
#define GIO_LCD_ENABLE (1<<5)

static struct mutex spi_mtx;

struct SPI_info {
    volatile unsigned short *setreg;
    volatile unsigned short *clrreg;
    int bit;
    unsigned short spi_mode;
    bool clk_invert;
};

static const struct SPI_info spi_targets[] =
{
#ifndef CREATIVE_ZVx
    [SPI_target_TSC2100]   = { &IO_GIO_BITCLR1, &IO_GIO_BITSET1, 
        GIO_TS_ENABLE, 0x260D, true},
    /* RTC seems to have timing problems if the CLK idles low */
    [SPI_target_RX5X348AB] = { &IO_GIO_BITSET0, &IO_GIO_BITCLR0, 
        GIO_RTC_ENABLE, 0x263F, true},
    /* This appears to work properly idling low, idling high is very glitchy */
    [SPI_target_BACKLIGHT] = { &IO_GIO_BITCLR1, &IO_GIO_BITSET1, 
        GIO_BL_ENABLE, 0x2656, false},
#else
    [SPI_target_LTV250QV] =  { &IO_GIO_BITCLR2, &IO_GIO_BITSET2, 
        GIO_LCD_ENABLE, true, 0x07},
#endif
};

#define IO_SERIAL0_XMIT         (0x100)

static void spi_disable_all_targets(void)
{
    int i;
    for(i=0;i<SPI_MAX_TARGETS;i++)
    {
        *spi_targets[i].clrreg = spi_targets[i].bit;
    }
}

int spi_block_transfer(enum SPI_target target,
                       const uint8_t *tx_bytes, unsigned int tx_size,
                             uint8_t *rx_bytes, unsigned int rx_size)
{
    mutex_lock(&spi_mtx);

    /* Enable the clock */
    bitset16(&IO_CLK_MOD2, CLK_MOD2_SIF0);
    
    if(spi_targets[target].clk_invert)
    {
        bitset16(&IO_CLK_INV, (1 << 12));
    }
    else
    {
        bitclr16(&IO_CLK_INV, (1 << 12));
    }

    IO_SERIAL0_MODE =   spi_targets[target].spi_mode;

    /* Activate the slave select pin */
    IO_SERIAL0_TX_ENABLE = 0x0001;
    *spi_targets[target].setreg = spi_targets[target].bit;

    while (IO_SERIAL0_RX_DATA & IO_SERIAL0_XMIT) {};

    while (tx_size--)
    {
        /* Send one byte */
        IO_SERIAL0_TX_DATA = (short)*tx_bytes++;
        /* Wait until transfer finished */
        while (IO_SERIAL0_RX_DATA & IO_SERIAL0_XMIT) {};
    }

    while (rx_size--)
    {
        unsigned short data;
        
        /* Make the clock tick */
        IO_SERIAL0_TX_DATA = 0;

        /* Wait until transfer finished */
        while ((data = IO_SERIAL0_RX_DATA) & IO_SERIAL0_XMIT) {};
        
        *rx_bytes++ = (unsigned char) data;
    }

    *spi_targets[target].clrreg = spi_targets[target].bit;
    
    IO_SERIAL0_TX_ENABLE = 0x0000;

    /* Disable the clock */
    bitclr16(&IO_CLK_MOD2, CLK_MOD2_SIF0);
    
    mutex_unlock(&spi_mtx);
    return 0;
}

void spi_init(void)
{
    mutex_init(&spi_mtx);

    /* Enable the clock */
    bitset16(&IO_CLK_MOD2, CLK_MOD2_SIF0);
    
    /* Disable transmitter */
    IO_SERIAL0_TX_ENABLE = 0x0000;
    
    IO_SERIAL0_MODE = 0x0230;
    
    /* Make sure the SPI clock is inverted */
    bitclr16(&IO_CLK_INV, ( 1 << 12 ));

    /* make sure only one is ever enabled at a time */
    spi_disable_all_targets();
    
    /* Disable the clock */
    bitclr16(&IO_CLK_MOD2, CLK_MOD2_SIF0);
}