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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., 51 Franklin Street, Fifth Floor, Boston,

    MA 02110-1301 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 

   Mux support by Rodolfo Giometti  and

   Michael Lawnick  */

#include 

#include 

#include 

#include 

#include 

#include 

#include 

#include 

#if 0

static ssize_t

show_modalias(struct device *dev, struct device_attribute *attr, char *buf)

{

	struct i2c_client *client = to_i2c_client(dev);

	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);

}

static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static struct attribute *i2c_dev_attrs[] = {

	&dev_attr_name.attr,

	/* modalias helps coldplug:  modprobe $(cat .../modalias) */

	&dev_attr_modalias.attr,

	NULL

};

static struct attribute_group i2c_dev_attr_group = {

	.attrs		= i2c_dev_attrs,

};

static const struct attribute_group *i2c_dev_attr_groups[] = {

	&i2c_dev_attr_group,

	NULL

};

static const struct dev_pm_ops i2c_device_pm_ops = {

	.suspend = i2c_device_pm_suspend,

	.resume = i2c_device_pm_resume,

	.freeze = i2c_device_pm_freeze,

	.thaw = i2c_device_pm_thaw,

	.poweroff = i2c_device_pm_poweroff,

	.restore = i2c_device_pm_restore,

	SET_RUNTIME_PM_OPS(

		pm_generic_runtime_suspend,

		pm_generic_runtime_resume,

		NULL

	)

};

struct bus_type i2c_bus_type = {

	.name		= "i2c",

	.match		= i2c_device_match,

	.probe		= i2c_device_probe,

	.remove		= i2c_device_remove,

	.shutdown	= i2c_device_shutdown,

	.pm		= &i2c_device_pm_ops,

};

EXPORT_SYMBOL_GPL(i2c_bus_type);

static struct device_type i2c_client_type = {

	.groups		= i2c_dev_attr_groups,

	.uevent		= i2c_device_uevent,

	.release	= i2c_client_dev_release,

};

/**

 * i2c_verify_client - return parameter as i2c_client, or NULL

 * @dev: device, probably from some driver model iterator

 *

 * When traversing the driver model tree, perhaps using driver model

 * iterators like @device_for_each_child(), you can't assume very much

 * about the nodes you find.  Use this function to avoid oopses caused

 * by wrongly treating some non-I2C device as an i2c_client.

 */

struct i2c_client *i2c_verify_client(struct device *dev)

{

	return (dev->type == &i2c_client_type)

			? to_i2c_client(dev)

			: NULL;

}

EXPORT_SYMBOL(i2c_verify_client);

/* This is a permissive address validity check, I2C address map constraints

 * are purposely not enforced, except for the general call address. */

static int i2c_check_client_addr_validity(const struct i2c_client *client)

{

	if (client->flags & I2C_CLIENT_TEN) {

		/* 10-bit address, all values are valid */

		if (client->addr > 0x3ff)

			return -EINVAL;

	} else {

		/* 7-bit address, reject the general call address */

		if (client->addr == 0x00 || client->addr > 0x7f)

			return -EINVAL;

	}

	return 0;

}

/* And this is a strict address validity check, used when probing. If a

 * device uses a reserved address, then it shouldn't be probed. 7-bit

 * addressing is assumed, 10-bit address devices are rare and should be

 * explicitly enumerated. */

static int i2c_check_addr_validity(unsigned short addr)

{

	/*

	 * Reserved addresses per I2C specification:

	 *  0x00       General call address / START byte

	 *  0x01       CBUS address

	 *  0x02       Reserved for different bus format

	 *  0x03       Reserved for future purposes

	 *  0x04-0x07  Hs-mode master code

	 *  0x78-0x7b  10-bit slave addressing

	 *  0x7c-0x7f  Reserved for future purposes

	 */

	if (addr < 0x08 || addr > 0x77)

		return -EINVAL;

	return 0;

}

static int __i2c_check_addr_busy(struct device *dev, void *addrp)

{

	struct i2c_client	*client = i2c_verify_client(dev);

	int			addr = *(int *)addrp;

	if (client && client->addr == addr)

		return -EBUSY;

	return 0;

}

/* walk up mux tree */

static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)

{

	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	int result;

	result = device_for_each_child(&adapter->dev, &addr,

					__i2c_check_addr_busy);

	if (!result && parent)

		result = i2c_check_mux_parents(parent, addr);

	return result;

}

/* recurse down mux tree */

static int i2c_check_mux_children(struct device *dev, void *addrp)

{

	int result;

	if (dev->type == &i2c_adapter_type)

		result = device_for_each_child(dev, addrp,

						i2c_check_mux_children);

	else

		result = __i2c_check_addr_busy(dev, addrp);

	return result;

}

static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)

{

	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	int result = 0;

	if (parent)

		result = i2c_check_mux_parents(parent, addr);

	if (!result)

		result = device_for_each_child(&adapter->dev, &addr,

						i2c_check_mux_children);

	return result;

}

/**

 * i2c_lock_adapter - Get exclusive access to an I2C bus segment

 * @adapter: Target I2C bus segment

 */

void i2c_lock_adapter(struct i2c_adapter *adapter)

{

	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)

		i2c_lock_adapter(parent);

	else

		rt_mutex_lock(&adapter->bus_lock);

}

EXPORT_SYMBOL_GPL(i2c_lock_adapter);

/**

 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment

 * @adapter: Target I2C bus segment

 */

static int i2c_trylock_adapter(struct i2c_adapter *adapter)

{

	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)

		return i2c_trylock_adapter(parent);

	else

		return rt_mutex_trylock(&adapter->bus_lock);

}

/**

 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment

 * @adapter: Target I2C bus segment

 */

void i2c_unlock_adapter(struct i2c_adapter *adapter)

{

	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)

		i2c_unlock_adapter(parent);

	else

		rt_mutex_unlock(&adapter->bus_lock);

}

EXPORT_SYMBOL_GPL(i2c_unlock_adapter);

#endif

/**

 * 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 = GetTimerTicks();

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

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

            if (ret != -EAGAIN)

                break;

            if (time_after(GetTimerTicks(), orig_jiffies + adap->timeout))

                break;

            delay(1);

        }

//        mutex_unlock(&adap->bus_lock);

        return ret;

    } else {

        dbgprintf("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;

}