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/* i2c-core.c - a device driver for the iic-bus interface		     */

/* ------------------------------------------------------------------------- */

/*   Copyright (C) 1995-99 Simon G. Vogl

    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., 675 Mass Ave, Cambridge, MA 02139, USA.		     */

/* ------------------------------------------------------------------------- */

/* With some changes from Kyösti Mälkki .

   All SMBus-related things are written by Frodo Looijaard 

   SMBus 2.0 support by Mark Studebaker  and

   Jean Delvare  */

#include 

#include 

#include 

#include 

#include 

/**

 * i2c_transfer - execute a single or combined I2C message

 * @adap: Handle to I2C bus

 * @msgs: One or more messages to execute before STOP is issued to

 *  terminate the operation; each message begins with a START.

 * @num: Number of messages to be executed.

 *

 * Returns negative errno, else the number of messages executed.

 *

 * Note that there is no requirement that each message be sent to

 * the same slave address, although that is the most common model.

 */

int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)

{

    unsigned long orig_jiffies;

    int ret, try;

    /* REVISIT the fault reporting model here is weak:

     *

     *  - When we get an error after receiving N bytes from a slave,

     *    there is no way to report "N".

     *

     *  - When we get a NAK after transmitting N bytes to a slave,

     *    there is no way to report "N" ... or to let the master

     *    continue executing the rest of this combined message, if

     *    that's the appropriate response.

     *

     *  - When for example "num" is two and we successfully complete

     *    the first message but get an error part way through the

     *    second, it's unclear whether that should be reported as

     *    one (discarding status on the second message) or errno

     *    (discarding status on the first one).

     */

    if (adap->algo->master_xfer) {

        /* Retry automatically on arbitration loss */

        orig_jiffies = 0;

        for (ret = 0, try = 0; try <= adap->retries; try++) {

            ret = adap->algo->master_xfer(adap, msgs, num);

            if (ret != -EAGAIN)

                break;

//            if (time_after(jiffies, orig_jiffies + adap->timeout))

//                break;

                delay(1);

        }

//        mutex_unlock(&adap->bus_lock);

        return ret;

    } else {

//        dev_dbg(&adap->dev, "I2C level transfers not supported\n");

        return -EOPNOTSUPP;

    }

}

EXPORT_SYMBOL(i2c_transfer);

/**

 * i2c_new_device - instantiate an i2c device

 * @adap: the adapter managing the device

 * @info: describes one I2C device; bus_num is ignored

 * Context: can sleep

 *

 * Create an i2c device. Binding is handled through driver model

 * probe()/remove() methods.  A driver may be bound to this device when we

 * return from this function, or any later moment (e.g. maybe hotplugging will

 * load the driver module).  This call is not appropriate for use by mainboard

 * initialization logic, which usually runs during an arch_initcall() long

 * before any i2c_adapter could exist.

 *

 * This returns the new i2c client, which may be saved for later use with

 * i2c_unregister_device(); or NULL to indicate an error.

 */

struct i2c_client *

i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)

{

    struct i2c_client   *client;

    int         status;

    client = kzalloc(sizeof *client, GFP_KERNEL);

    if (!client)

        return NULL;

    client->adapter = adap;

    client->flags = info->flags;

    client->addr = info->addr;

    client->irq = info->irq;

    strlcpy(client->name, info->type, sizeof(client->name));

    return client;

}