flexcop-i2c.c

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/*
 * Linux driver for digital TV devices equipped with B2C2 FlexcopII(b)/III
 * flexcop-i2c.c - flexcop internal 2Wire bus (I2C) and dvb i2c initialization
 * see flexcop.c for copyright information
 */
#include "flexcop.h"

#define FC_MAX_I2C_RETRIES 100000

static int flexcop_i2c_operation(struct flexcop_device *fc,
        flexcop_ibi_value *r100)
{
    int i;
    flexcop_ibi_value r;

    r100->tw_sm_c_100.working_start = 1;
    deb_i2c("r100 before: %08x\n",r100->raw);

    fc->write_ibi_reg(fc, tw_sm_c_100, ibi_zero);
    fc->write_ibi_reg(fc, tw_sm_c_100, *r100); /* initiating i2c operation */

    for (i = 0; i < FC_MAX_I2C_RETRIES; i++) {
        r = fc->read_ibi_reg(fc, tw_sm_c_100);

        if (!r.tw_sm_c_100.no_base_addr_ack_error) {
            if (r.tw_sm_c_100.st_done) {
                *r100 = r;
                deb_i2c("i2c success\n");
                return 0;
            }
        } else {
            deb_i2c("suffering from an i2c ack_error\n");
            return -EREMOTEIO;
        }
    }
    deb_i2c("tried %d times i2c operation, "
            "never finished or too many ack errors.\n", i);
    return -EREMOTEIO;
}

static int flexcop_i2c_read4(struct flexcop_i2c_adapter *i2c,
        flexcop_ibi_value r100, u8 *buf)
{
    flexcop_ibi_value r104;
    int len = r100.tw_sm_c_100.total_bytes,
        /* remember total_bytes is buflen-1 */
        ret;

    /* work-around to have CableStar2 and SkyStar2 rev 2.7 work
     * correctly:
     *
     * the ITD1000 is behind an i2c-gate which closes automatically
     * after an i2c-transaction the STV0297 needs 2 consecutive reads
     * one with no_base_addr = 0 and one with 1
     *
     * those two work-arounds are conflictin: we check for the card
     * type, it is set when probing the ITD1000 */
    if (i2c->fc->dev_type == FC_SKY_REV27)
        r100.tw_sm_c_100.no_base_addr_ack_error = i2c->no_base_addr;

    ret = flexcop_i2c_operation(i2c->fc, &r100);
    if (ret != 0) {
        deb_i2c("Retrying operation\n");
        r100.tw_sm_c_100.no_base_addr_ack_error = i2c->no_base_addr;
        ret = flexcop_i2c_operation(i2c->fc, &r100);
    }
    if (ret != 0) {
        deb_i2c("read failed. %d\n", ret);
        return ret;
    }

    buf[0] = r100.tw_sm_c_100.data1_reg;

    if (len > 0) {
        r104 = i2c->fc->read_ibi_reg(i2c->fc, tw_sm_c_104);
        deb_i2c("read: r100: %08x, r104: %08x\n", r100.raw, r104.raw);

        /* there is at least one more byte, otherwise we wouldn't be here */
        buf[1] = r104.tw_sm_c_104.data2_reg;
        if (len > 1) buf[2] = r104.tw_sm_c_104.data3_reg;
        if (len > 2) buf[3] = r104.tw_sm_c_104.data4_reg;
    }
    return 0;
}

static int flexcop_i2c_write4(struct flexcop_device *fc,
        flexcop_ibi_value r100, u8 *buf)
{
    flexcop_ibi_value r104;
    int len = r100.tw_sm_c_100.total_bytes; /* remember total_bytes is buflen-1 */
    r104.raw = 0;

    /* there is at least one byte, otherwise we wouldn't be here */
    r100.tw_sm_c_100.data1_reg = buf[0];
    r104.tw_sm_c_104.data2_reg = len > 0 ? buf[1] : 0;
    r104.tw_sm_c_104.data3_reg = len > 1 ? buf[2] : 0;
    r104.tw_sm_c_104.data4_reg = len > 2 ? buf[3] : 0;

    deb_i2c("write: r100: %08x, r104: %08x\n", r100.raw, r104.raw);

    /* write the additional i2c data before doing the actual i2c operation */
    fc->write_ibi_reg(fc, tw_sm_c_104, r104);
    return flexcop_i2c_operation(fc, &r100);
}

int flexcop_i2c_request(struct flexcop_i2c_adapter *i2c,
        flexcop_access_op_t op, u8 chipaddr, u8 addr, u8 *buf, u16 len)
{
    int ret;

#ifdef DUMP_I2C_MESSAGES
    int i;
#endif

    u16 bytes_to_transfer;
    flexcop_ibi_value r100;

    deb_i2c("op = %d\n",op);
    r100.raw = 0;
    r100.tw_sm_c_100.chipaddr = chipaddr;
    r100.tw_sm_c_100.twoWS_rw = op;
    r100.tw_sm_c_100.twoWS_port_reg = i2c->port;

#ifdef DUMP_I2C_MESSAGES
    printk(KERN_DEBUG "%d ", i2c->port);
    if (op == FC_READ)
        printk("rd(");
    else
        printk("wr(");
    printk("%02x): %02x ", chipaddr, addr);
#endif

    /* in that case addr is the only value ->
     * we write it twice as baseaddr and val0
     * BBTI is doing it like that for ISL6421 at least */
    if (i2c->no_base_addr && len == 0 && op == FC_WRITE) {
        buf = &addr;
        len = 1;
    }

    while (len != 0) {
        bytes_to_transfer = len > 4 ? 4 : len;

        r100.tw_sm_c_100.total_bytes = bytes_to_transfer - 1;
        r100.tw_sm_c_100.baseaddr = addr;

        if (op == FC_READ)
            ret = flexcop_i2c_read4(i2c, r100, buf);
        else
            ret = flexcop_i2c_write4(i2c->fc, r100, buf);

#ifdef DUMP_I2C_MESSAGES
        for (i = 0; i < bytes_to_transfer; i++)
            printk("%02x ", buf[i]);
#endif

        if (ret < 0)
            return ret;

        buf  += bytes_to_transfer;
        addr += bytes_to_transfer;
        len  -= bytes_to_transfer;
    }

#ifdef DUMP_I2C_MESSAGES
    printk("\n");
#endif

    return 0;
}
/* exported for PCI i2c */
EXPORT_SYMBOL(flexcop_i2c_request);

/* master xfer callback for demodulator */
static int flexcop_master_xfer(struct i2c_adapter *i2c_adap,
        struct i2c_msg msgs[], int num)
{
    struct flexcop_i2c_adapter *i2c = i2c_get_adapdata(i2c_adap);
    int i, ret = 0;

    /* Some drivers use 1 byte or 0 byte reads as probes, which this
     * driver doesn't support.  These probes will always fail, so this
     * hack makes them always succeed.  If one knew how, it would of
     * course be better to actually do the read.  */
    if (num == 1 && msgs[0].flags == I2C_M_RD && msgs[0].len <= 1)
        return 1;

    if (mutex_lock_interruptible(&i2c->fc->i2c_mutex))
        return -ERESTARTSYS;

    for (i = 0; i < num; i++) {
        /* reading */
        if (i+1 < num && (msgs[i+1].flags == I2C_M_RD)) {
            ret = i2c->fc->i2c_request(i2c, FC_READ, msgs[i].addr,
                    msgs[i].buf[0], msgs[i+1].buf,
                    msgs[i+1].len);
            i++; /* skip the following message */
        } else /* writing */
            ret = i2c->fc->i2c_request(i2c, FC_WRITE, msgs[i].addr,
                    msgs[i].buf[0], &msgs[i].buf[1],
                    msgs[i].len - 1);
        if (ret < 0) {
            deb_i2c("i2c master_xfer failed");
            break;
        }
    }

    mutex_unlock(&i2c->fc->i2c_mutex);

    if (ret == 0)
        ret = num;
    return ret;
}

static u32 flexcop_i2c_func(struct i2c_adapter *adapter)
{
    return I2C_FUNC_I2C;
}

static struct i2c_algorithm flexcop_algo = {
    .master_xfer    = flexcop_master_xfer,
    .functionality  = flexcop_i2c_func,
};

int flexcop_i2c_init(struct flexcop_device *fc)
{
    int ret;
    mutex_init(&fc->i2c_mutex);

    fc->fc_i2c_adap[0].fc = fc;
    fc->fc_i2c_adap[1].fc = fc;
    fc->fc_i2c_adap[2].fc = fc;
    fc->fc_i2c_adap[0].port = FC_I2C_PORT_DEMOD;
    fc->fc_i2c_adap[1].port = FC_I2C_PORT_EEPROM;
    fc->fc_i2c_adap[2].port = FC_I2C_PORT_TUNER;

    strlcpy(fc->fc_i2c_adap[0].i2c_adap.name, "B2C2 FlexCop I2C to demod",
            sizeof(fc->fc_i2c_adap[0].i2c_adap.name));
    strlcpy(fc->fc_i2c_adap[1].i2c_adap.name, "B2C2 FlexCop I2C to eeprom",
            sizeof(fc->fc_i2c_adap[1].i2c_adap.name));
    strlcpy(fc->fc_i2c_adap[2].i2c_adap.name, "B2C2 FlexCop I2C to tuner",
            sizeof(fc->fc_i2c_adap[2].i2c_adap.name));

    i2c_set_adapdata(&fc->fc_i2c_adap[0].i2c_adap, &fc->fc_i2c_adap[0]);
    i2c_set_adapdata(&fc->fc_i2c_adap[1].i2c_adap, &fc->fc_i2c_adap[1]);
    i2c_set_adapdata(&fc->fc_i2c_adap[2].i2c_adap, &fc->fc_i2c_adap[2]);

    fc->fc_i2c_adap[0].i2c_adap.algo =
        fc->fc_i2c_adap[1].i2c_adap.algo =
        fc->fc_i2c_adap[2].i2c_adap.algo = &flexcop_algo;
    fc->fc_i2c_adap[0].i2c_adap.algo_data =
        fc->fc_i2c_adap[1].i2c_adap.algo_data =
        fc->fc_i2c_adap[2].i2c_adap.algo_data = NULL;
    fc->fc_i2c_adap[0].i2c_adap.dev.parent =
        fc->fc_i2c_adap[1].i2c_adap.dev.parent =
        fc->fc_i2c_adap[2].i2c_adap.dev.parent = fc->dev;

    ret = i2c_add_adapter(&fc->fc_i2c_adap[0].i2c_adap);
    if (ret < 0)
        return ret;

    ret = i2c_add_adapter(&fc->fc_i2c_adap[1].i2c_adap);
    if (ret < 0)
        goto adap_1_failed;

    ret = i2c_add_adapter(&fc->fc_i2c_adap[2].i2c_adap);
    if (ret < 0)
        goto adap_2_failed;

    fc->init_state |= FC_STATE_I2C_INIT;
    return 0;

adap_2_failed:
    i2c_del_adapter(&fc->fc_i2c_adap[1].i2c_adap);
adap_1_failed:
    i2c_del_adapter(&fc->fc_i2c_adap[0].i2c_adap);
    return ret;
}

void flexcop_i2c_exit(struct flexcop_device *fc)
{
    if (fc->init_state & FC_STATE_I2C_INIT) {
        i2c_del_adapter(&fc->fc_i2c_adap[2].i2c_adap);
        i2c_del_adapter(&fc->fc_i2c_adap[1].i2c_adap);
        i2c_del_adapter(&fc->fc_i2c_adap[0].i2c_adap);
    }
    fc->init_state &= ~FC_STATE_I2C_INIT;
}