mv64x60_i2c.c

Go to the documentation of this file.

/*
 * Bootloader version of the i2c driver for the MV64x60.
 *
 * Author: Dale Farnsworth <[email protected]>
 * Maintained by: Mark A. Greer <[email protected]>
 *
 * 2003, 2007 (c) MontaVista, Software, Inc.  This file is licensed under
 * the terms of the GNU General Public License version 2.  This program is
 * licensed "as is" without any warranty of any kind, whether express or
 * implied.
 */

#include <stdarg.h>
#include <stddef.h>
#include "types.h"
#include "elf.h"
#include "page.h"
#include "string.h"
#include "stdio.h"
#include "io.h"
#include "ops.h"
#include "mv64x60.h"

/* Register defines */
#define MV64x60_I2C_REG_SLAVE_ADDR          0x00
#define MV64x60_I2C_REG_DATA                0x04
#define MV64x60_I2C_REG_CONTROL             0x08
#define MV64x60_I2C_REG_STATUS              0x0c
#define MV64x60_I2C_REG_BAUD                0x0c
#define MV64x60_I2C_REG_EXT_SLAVE_ADDR          0x10
#define MV64x60_I2C_REG_SOFT_RESET          0x1c

#define MV64x60_I2C_CONTROL_ACK             0x04
#define MV64x60_I2C_CONTROL_IFLG            0x08
#define MV64x60_I2C_CONTROL_STOP            0x10
#define MV64x60_I2C_CONTROL_START           0x20
#define MV64x60_I2C_CONTROL_TWSIEN          0x40
#define MV64x60_I2C_CONTROL_INTEN           0x80

#define MV64x60_I2C_STATUS_BUS_ERR          0x00
#define MV64x60_I2C_STATUS_MAST_START           0x08
#define MV64x60_I2C_STATUS_MAST_REPEAT_START        0x10
#define MV64x60_I2C_STATUS_MAST_WR_ADDR_ACK     0x18
#define MV64x60_I2C_STATUS_MAST_WR_ADDR_NO_ACK      0x20
#define MV64x60_I2C_STATUS_MAST_WR_ACK          0x28
#define MV64x60_I2C_STATUS_MAST_WR_NO_ACK       0x30
#define MV64x60_I2C_STATUS_MAST_LOST_ARB        0x38
#define MV64x60_I2C_STATUS_MAST_RD_ADDR_ACK     0x40
#define MV64x60_I2C_STATUS_MAST_RD_ADDR_NO_ACK      0x48
#define MV64x60_I2C_STATUS_MAST_RD_DATA_ACK     0x50
#define MV64x60_I2C_STATUS_MAST_RD_DATA_NO_ACK      0x58
#define MV64x60_I2C_STATUS_MAST_WR_ADDR_2_ACK       0xd0
#define MV64x60_I2C_STATUS_MAST_WR_ADDR_2_NO_ACK    0xd8
#define MV64x60_I2C_STATUS_MAST_RD_ADDR_2_ACK       0xe0
#define MV64x60_I2C_STATUS_MAST_RD_ADDR_2_NO_ACK    0xe8
#define MV64x60_I2C_STATUS_NO_STATUS            0xf8

static u8 *ctlr_base;

static int mv64x60_i2c_wait_for_status(int wanted)
{
    int i;
    int status;

    for (i=0; i<1000; i++) {
        udelay(10);
        status = in_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_STATUS))
            & 0xff;
        if (status == wanted)
            return status;
    }
    return -status;
}

static int mv64x60_i2c_control(int control, int status)
{
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_CONTROL), control & 0xff);
    return mv64x60_i2c_wait_for_status(status);
}

static int mv64x60_i2c_read_byte(int control, int status)
{
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_CONTROL), control & 0xff);
    if (mv64x60_i2c_wait_for_status(status) < 0)
        return -1;
    return in_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_DATA)) & 0xff;
}

static int mv64x60_i2c_write_byte(int data, int control, int status)
{
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_DATA), data & 0xff);
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_CONTROL), control & 0xff);
    return mv64x60_i2c_wait_for_status(status);
}

int mv64x60_i2c_read(u32 devaddr, u8 *buf, u32 offset, u32 offset_size,
         u32 count)
{
    int i;
    int data;
    int control;
    int status;

    if (ctlr_base == NULL)
        return -1;

    /* send reset */
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_SOFT_RESET), 0);
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_SLAVE_ADDR), 0);
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_EXT_SLAVE_ADDR), 0);
    out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_BAUD), (4 << 3) | 0x4);

    if (mv64x60_i2c_control(MV64x60_I2C_CONTROL_TWSIEN,
                MV64x60_I2C_STATUS_NO_STATUS) < 0)
        return -1;

    /* send start */
    control = MV64x60_I2C_CONTROL_START | MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_MAST_START;
    if (mv64x60_i2c_control(control, status) < 0)
        return -1;

    /* select device for writing */
    data = devaddr & ~0x1;
    control = MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_MAST_WR_ADDR_ACK;
    if (mv64x60_i2c_write_byte(data, control, status) < 0)
        return -1;

    /* send offset of data */
    control = MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_MAST_WR_ACK;
    if (offset_size > 1) {
        if (mv64x60_i2c_write_byte(offset >> 8, control, status) < 0)
            return -1;
    }
    if (mv64x60_i2c_write_byte(offset, control, status) < 0)
        return -1;

    /* resend start */
    control = MV64x60_I2C_CONTROL_START | MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_MAST_REPEAT_START;
    if (mv64x60_i2c_control(control, status) < 0)
        return -1;

    /* select device for reading */
    data = devaddr | 0x1;
    control = MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_MAST_RD_ADDR_ACK;
    if (mv64x60_i2c_write_byte(data, control, status) < 0)
        return -1;

    /* read all but last byte of data */
    control = MV64x60_I2C_CONTROL_ACK | MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_MAST_RD_DATA_ACK;

    for (i=1; i<count; i++) {
        data = mv64x60_i2c_read_byte(control, status);
        if (data < 0) {
            printf("errors on iteration %d\n", i);
            return -1;
        }
        *buf++ = data;
    }

    /* read last byte of data */
    control = MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_MAST_RD_DATA_NO_ACK;
    data = mv64x60_i2c_read_byte(control, status);
    if (data < 0)
        return -1;
    *buf++ = data;

    /* send stop */
    control = MV64x60_I2C_CONTROL_STOP | MV64x60_I2C_CONTROL_TWSIEN;
    status = MV64x60_I2C_STATUS_NO_STATUS;
    if (mv64x60_i2c_control(control, status) < 0)
        return -1;

    return count;
}

int mv64x60_i2c_open(void)
{
    u32 v;
    void *devp;

    devp = find_node_by_compatible(NULL, "marvell,mv64360-i2c");
    if (devp == NULL)
        goto err_out;
    if (getprop(devp, "virtual-reg", &v, sizeof(v)) != sizeof(v))
        goto err_out;

    ctlr_base = (u8 *)v;
    return 0;

err_out:
    return -1;
}

void mv64x60_i2c_close(void)
{
    ctlr_base = NULL;
}