rockbox/firmware/target/arm/i2c-pp.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * PP502X and PP5002 I2C driver
 *
 * Based on code from the ipodlinux project - http://ipodlinux.org/
 * Adapted for Rockbox in November 2005
 *
 * Original file: linux/arch/armnommu/mach-ipod/hardware.c
 *
 * Copyright (c) 2003-2005 Bernard Leach (leachbj@bouncycastle.org)
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include "cpu.h"
#include "kernel.h"
#include "thread.h"
#include "logf.h"
#include "system.h"
#include "i2c-pp.h"

/* Local functions definitions */

#define POLL_TIMEOUT (HZ)

static int pp_i2c_wait_not_busy(void)
{
    unsigned long timeout;
    timeout = current_tick + POLL_TIMEOUT;
    while (TIME_BEFORE(current_tick, timeout)) {
         if (!(I2C_STATUS & I2C_BUSY)) {
            return 0;
         }
         priority_yield();
    }

    return -1;
}

static int pp_i2c_read_byte(unsigned int addr, unsigned int *data)
{
    if (pp_i2c_wait_not_busy() < 0)
    {
        return -1;
    }

    {
        unsigned int byte;
        int old_irq_level = set_irq_level(HIGHEST_IRQ_LEVEL);

        /* clear top 15 bits, left shift 1, or in 0x1 for a read */
        I2C_ADDR = ((addr << 17) >> 16) | 0x1 ;

        I2C_CTRL |= 0x20;

        I2C_CTRL |= I2C_SEND;

        set_irq_level(old_irq_level);
        if (pp_i2c_wait_not_busy() < 0)
        {
            return -1;
        }
        old_irq_level = set_irq_level(HIGHEST_IRQ_LEVEL);

        byte = I2C_DATA(0);

        if (data)
            *data = byte;

        set_irq_level(old_irq_level);
    }

    return 0;
}

static int pp_i2c_send_bytes(unsigned int addr, unsigned int len, unsigned char *data)
{
    unsigned int i;

    if (len < 1 || len > 4)
    {
        return -1;
    }

    if (pp_i2c_wait_not_busy() < 0)
    {
        return -2;
    }

    {
        int old_irq_level = set_irq_level(HIGHEST_IRQ_LEVEL);

        /* clear top 15 bits, left shift 1 */
        I2C_ADDR = (addr << 17) >> 16;

        I2C_CTRL &= ~0x20;

        for ( i = 0; i < len; i++ )
        {
            I2C_DATA(i) = *data++;
        }

        I2C_CTRL = (I2C_CTRL & ~0x26) | ((len-1) << 1);

        I2C_CTRL |= I2C_SEND;

        set_irq_level(old_irq_level);
    }

    return 0x0;
}

static int pp_i2c_send_byte(unsigned int addr, int data0)
{
    unsigned char data[1];

    data[0] = data0;

    return pp_i2c_send_bytes(addr, 1, data);
}

/* Public functions */
static struct mutex i2c_mutex;

int i2c_readbytes(unsigned int dev_addr, int addr, int len, unsigned char *data) {
    unsigned int temp;
    int i;
    spinlock_lock(&i2c_mutex);
    pp_i2c_send_byte(dev_addr, addr);
    for (i = 0; i < len; i++) {
        pp_i2c_read_byte(dev_addr, &temp);
        data[i] = temp;
    }
    spinlock_unlock(&i2c_mutex);
    return i;
}

int i2c_readbyte(unsigned int dev_addr, int addr)
{
    int data;

    spinlock_lock(&i2c_mutex);
    pp_i2c_send_byte(dev_addr, addr);
    pp_i2c_read_byte(dev_addr, &data);
    spinlock_unlock(&i2c_mutex);

    return data;
}

int pp_i2c_send(unsigned int addr, int data0, int data1)
{
    int retval;
    unsigned char data[2];

    data[0] = data0;
    data[1] = data1;

    spinlock_lock(&i2c_mutex);
    retval = pp_i2c_send_bytes(addr, 2, data);
    spinlock_unlock(&i2c_mutex);

    return retval;
}

void i2c_init(void)
{
    /* From ipodlinux */

#ifdef IPOD_MINI
    /* GPIO port C disable port 0x10 */
    GPIOC_ENABLE &= ~0x10;

    /* GPIO port C disable port 0x20 */
    GPIOC_ENABLE &= ~0x20;
#endif

#if CONFIG_I2C == I2C_PP5002
    DEV_EN |= 0x2;
#else
    DEV_EN |= DEV_I2C;  /* Enable I2C */
#endif
    DEV_RS |= DEV_I2C;  /* Start I2C Reset */
    DEV_RS &=~DEV_I2C;  /* End I2C Reset */

#if CONFIG_I2C == I2C_PP5020
    outl(0x0, 0x600060a4);
    outl(0x80 | (0 << 8), 0x600060a4);
#endif

    spinlock_init(&i2c_mutex);

    i2c_readbyte(0x8, 0);
}