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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 <kmalkki@cc.hut.fi>.

   All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>

   SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com>                */

/* $Id: i2c-core.c,v 1.1 2004-01-28 15:12:01 giacomo Exp $ */

/* #define DEBUG 1 */           /* needed to pick up the dev_dbg() calls */

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/slab.h>

#include <linux/i2c.h>

#include <linux/init.h>

#include <linux/seq_file.h>

#include <asm/uaccess.h>

#define DEB(x) if (i2c_debug>=1) x;

#define DEB2(x) if (i2c_debug>=2) x;

static LIST_HEAD(adapters);

static LIST_HEAD(drivers);

static DECLARE_MUTEX(core_lists);

/**** debug level */

static int i2c_debug;

int i2c_device_probe(struct device *dev)

{

        return -ENODEV;

}

int i2c_device_remove(struct device *dev)

{

        return 0;

}

static void i2c_adapter_dev_release(struct device *dev)

{

        struct i2c_adapter *adap = dev_to_i2c_adapter(dev);

        complete(&adap->dev_released);

}

static struct device_driver i2c_adapter_driver = {

        .name = "i2c_adapter",

        .bus = &i2c_bus_type,

        .probe = i2c_device_probe,

        .remove = i2c_device_remove,

};

static void i2c_adapter_class_dev_release(struct class_device *dev)

{

        struct i2c_adapter *adap = class_dev_to_i2c_adapter(dev);

        complete(&adap->class_dev_released);

}

static struct class i2c_adapter_class = {

        .name =         "i2c-adapter",

        .release =      &i2c_adapter_class_dev_release,

};

static ssize_t show_adapter_name(struct device *dev, char *buf)

{

        struct i2c_adapter *adap = dev_to_i2c_adapter(dev);

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

}

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

static void i2c_client_release(struct device *dev)

{

        struct i2c_client *client = to_i2c_client(dev);

        complete(&client->released);

}

static ssize_t show_client_name(struct device *dev, char *buf)

{

        struct i2c_client *client = to_i2c_client(dev);

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

}

/*

 * We can't use the DEVICE_ATTR() macro here as we want the same filename for a

 * different type of a device.  So beware if the DEVICE_ATTR() macro ever

 * changes, this definition will also have to change.

 */

static struct device_attribute dev_attr_client_name = {

        .attr   = {.name = "name", .mode = S_IRUGO, .owner = THIS_MODULE },

        .show   = &show_client_name,

};

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

 * registering functions

 * ---------------------------------------------------

 */

/* -----

 * i2c_add_adapter is called from within the algorithm layer,

 * when a new hw adapter registers. A new device is register to be

 * available for clients.

 */

int i2c_add_adapter(struct i2c_adapter *adap)

{

        static int nr = 0;

        struct list_head   *item;

        struct i2c_driver  *driver;

        down(&core_lists);

        adap->nr = nr++;

        init_MUTEX(&adap->bus_lock);

        init_MUTEX(&adap->clist_lock);

        list_add_tail(&adap->list,&adapters);

        INIT_LIST_HEAD(&adap->clients);

        /* Add the adapter to the driver core.

         * If the parent pointer is not set up,

         * we add this adapter to the legacy bus.

         */

        if (adap->dev.parent == NULL)

                adap->dev.parent = &legacy_bus;

        sprintf(adap->dev.bus_id, "i2c-%d", adap->nr);

        adap->dev.driver = &i2c_adapter_driver;

        adap->dev.release = &i2c_adapter_dev_release;

        device_register(&adap->dev);

        device_create_file(&adap->dev, &dev_attr_name);

        /* Add this adapter to the i2c_adapter class */

        memset(&adap->class_dev, 0x00, sizeof(struct class_device));

        adap->class_dev.dev = &adap->dev;

        adap->class_dev.class = &i2c_adapter_class;

        strlcpy(adap->class_dev.class_id, adap->dev.bus_id, BUS_ID_SIZE);

        class_device_register(&adap->class_dev);

        /* inform drivers of new adapters */

        list_for_each(item,&drivers) {

                driver = list_entry(item, struct i2c_driver, list);

                if (driver->flags & I2C_DF_NOTIFY)

                        /* We ignore the return code; if it fails, too bad */

                        driver->attach_adapter(adap);

        }

        up(&core_lists);

        DEB(dev_dbg(&adap->dev, "registered as adapter #%d\n", adap->nr));

        return 0;

}

int i2c_del_adapter(struct i2c_adapter *adap)

{

        struct list_head  *item, *_n;

        struct i2c_driver *driver;

        struct i2c_client *client;

        int res = 0;

        down(&core_lists);

        list_for_each(item,&drivers) {

                driver = list_entry(item, struct i2c_driver, list);

                if (driver->detach_adapter)

                        if ((res = driver->detach_adapter(adap))) {

                                dev_warn(&adap->dev, "can't detach adapter"

                                         "while detaching driver %s: driver not "

                                         "detached!", driver->name);

                                goto out_unlock;

                        }

        }

        /* detach any active clients. This must be done first, because

         * it can fail; in which case we give upp. */

        list_for_each_safe(item, _n, &adap->clients) {

                client = list_entry(item, struct i2c_client, list);

                /* detaching devices is unconditional of the set notify

                 * flag, as _all_ clients that reside on the adapter

                 * must be deleted, as this would cause invalid states.

                 */

                if ((res=client->driver->detach_client(client))) {

                        dev_err(&adap->dev, "adapter not "

                                "unregistered, because client at "

                                "address %02x can't be detached. ",

                                client->addr);

                        goto out_unlock;

                }

        }

        /* clean up the sysfs representation */

        init_completion(&adap->dev_released);

        init_completion(&adap->class_dev_released);

        class_device_unregister(&adap->class_dev);

        device_remove_file(&adap->dev, &dev_attr_name);

        device_unregister(&adap->dev);

        list_del(&adap->list);

        /* wait for sysfs to drop all references */

        wait_for_completion(&adap->dev_released);

        wait_for_completion(&adap->class_dev_released);

        DEB(dev_dbg(&adap->dev, "adapter unregistered\n"));

 out_unlock:

        up(&core_lists);

        return res;

}

/* -----

 * What follows is the "upwards" interface: commands for talking to clients,

 * which implement the functions to access the physical information of the

 * chips.

 */

int i2c_add_driver(struct i2c_driver *driver)

{

        struct list_head   *item;

        struct i2c_adapter *adapter;

        int res = 0;

        down(&core_lists);

        /* add the driver to the list of i2c drivers in the driver core */

        driver->driver.name = driver->name;

        driver->driver.bus = &i2c_bus_type;

        driver->driver.probe = i2c_device_probe;

        driver->driver.remove = i2c_device_remove;

        res = driver_register(&driver->driver);

        if (res)

                goto out_unlock;

        list_add_tail(&driver->list,&drivers);

        DEB(printk(KERN_DEBUG "i2c-core.o: driver %s registered.\n",driver->name));

        /* now look for instances of driver on our adapters */

        if (driver->flags & I2C_DF_NOTIFY) {

                list_for_each(item,&adapters) {

                        adapter = list_entry(item, struct i2c_adapter, list);

                        driver->attach_adapter(adapter);

                }

        }

 out_unlock:

        up(&core_lists);

        return res;

}

int i2c_del_driver(struct i2c_driver *driver)

{

        struct list_head   *item1, *item2, *_n;

        struct i2c_client  *client;

        struct i2c_adapter *adap;

        int res = 0;

        down(&core_lists);

        /* Have a look at each adapter, if clients of this driver are still

         * attached. If so, detach them to be able to kill the driver

         * afterwards.

         */

        DEB2(printk(KERN_DEBUG "i2c-core.o: unregister_driver - looking for clients.\n"));

        /* removing clients does not depend on the notify flag, else

         * invalid operation might (will!) result, when using stale client

         * pointers.

         */

        list_for_each(item1,&adapters) {

                adap = list_entry(item1, struct i2c_adapter, list);

                DEB2(dev_dbg(&adap->dev, "examining adapter\n"));

                if (driver->detach_adapter) {

                        if ((res = driver->detach_adapter(adap))) {

                                dev_warn(&adap->dev, "while unregistering "

                                       "dummy driver %s, adapter could "

                                       "not be detached properly; driver "

                                       "not unloaded!",driver->name);

                                goto out_unlock;

                        }

                } else {

                        list_for_each_safe(item2, _n, &adap->clients) {

                                client = list_entry(item2, struct i2c_client, list);

                                if (client->driver != driver)

                                        continue;

                                DEB2(printk(KERN_DEBUG "i2c-core.o: "

                                            "detaching client %s:\n",

                                            client->name));

                                if ((res = driver->detach_client(client))) {

                                        dev_err(&adap->dev, "while "

                                                "unregistering driver "

                                                "`%s', the client at "

                                                "address %02x of "

                                                "adapter could not "

                                                "be detached; driver "

                                                "not unloaded!",

                                                driver->name,

                                                client->addr);

                                        goto out_unlock;

                                }

                        }

                }

        }

        driver_unregister(&driver->driver);

        list_del(&driver->list);

        DEB(printk(KERN_DEBUG "i2c-core.o: driver unregistered: %s\n",driver->name));

 out_unlock:

        up(&core_lists);

        return 0;

}

static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr)

{

        struct list_head   *item;

        struct i2c_client  *client;

        list_for_each(item,&adapter->clients) {

                client = list_entry(item, struct i2c_client, list);

                if (client->addr == addr)

                        return -EBUSY;

        }

        return 0;

}

int i2c_check_addr(struct i2c_adapter *adapter, int addr)

{

        int rval;

        down(&adapter->clist_lock);

        rval = __i2c_check_addr(adapter, addr);

        up(&adapter->clist_lock);

        return rval;

}

int i2c_attach_client(struct i2c_client *client)

{

        struct i2c_adapter *adapter = client->adapter;

        down(&adapter->clist_lock);

        if (__i2c_check_addr(client->adapter, client->addr)) {

                up(&adapter->clist_lock);

                return -EBUSY;

        }

        list_add_tail(&client->list,&adapter->clients);

        up(&adapter->clist_lock);

        if (adapter->client_register)  {

                if (adapter->client_register(client))  {

                        dev_warn(&adapter->dev, "warning: client_register "

                                "seems to have failed for client %02x\n",

                                client->addr);

                }

        }

        DEB(dev_dbg(&adapter->dev, "client [%s] registered to adapter\n",

                        client->dev.name));

        if (client->flags & I2C_CLIENT_ALLOW_USE)

                client->usage_count = 0;

        client->dev.parent = &client->adapter->dev;

        client->dev.driver = &client->driver->driver;

        client->dev.bus = &i2c_bus_type;

        client->dev.release = &i2c_client_release;

        snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id),

                "%d-%04x", i2c_adapter_id(adapter), client->addr);

        printk("registering %s\n", client->dev.bus_id);

        device_register(&client->dev);

        device_create_file(&client->dev, &dev_attr_client_name);

        return 0;

}

int i2c_detach_client(struct i2c_client *client)

{

        struct i2c_adapter *adapter = client->adapter;

        int res = 0;

        if ((client->flags & I2C_CLIENT_ALLOW_USE) && (client->usage_count > 0))

                return -EBUSY;

        if (adapter->client_unregister)  {

                res = adapter->client_unregister(client);

                if (res) {

                        printk(KERN_ERR

                               "i2c-core.o: client_unregister [%s] failed, "

                               "client not detached", client->name);

                        goto out;

                }

        }

        down(&adapter->clist_lock);

        list_del(&client->list);

        init_completion(&client->released);

        device_remove_file(&client->dev, &dev_attr_client_name);

        device_unregister(&client->dev);

        up(&adapter->clist_lock);

        wait_for_completion(&client->released);

 out:

        return res;

}

static int i2c_inc_use_client(struct i2c_client *client)

{

        if (!try_module_get(client->driver->owner))

                return -ENODEV;

        if (!try_module_get(client->adapter->owner)) {

                module_put(client->driver->owner);

                return -ENODEV;

        }

        return 0;

}

static void i2c_dec_use_client(struct i2c_client *client)

{

        module_put(client->driver->owner);

        module_put(client->adapter->owner);

}

int i2c_use_client(struct i2c_client *client)

{

        if (!i2c_inc_use_client(client))

                return -ENODEV;

        if (client->flags & I2C_CLIENT_ALLOW_USE) {

                if (client->flags & I2C_CLIENT_ALLOW_MULTIPLE_USE)

                        client->usage_count++;

                else if (client->usage_count > 0)

                        goto busy;

                else

                        client->usage_count++;

        }

        return 0;

 busy:

        i2c_dec_use_client(client);

        return -EBUSY;

}

int i2c_release_client(struct i2c_client *client)

{

        if(client->flags & I2C_CLIENT_ALLOW_USE) {

                if(client->usage_count>0)

                        client->usage_count--;

                else

                {

                        printk(KERN_WARNING " i2c-core.o: dec_use_client used one too many times\n");

                        return -EPERM;

                }

        }

        i2c_dec_use_client(client);

        return 0;

}

void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)

{

        struct list_head  *item;

        struct i2c_client *client;

        down(&adap->clist_lock);

        list_for_each(item,&adap->clients) {

                client = list_entry(item, struct i2c_client, list);

                if (!try_module_get(client->driver->owner))

                        continue;

                if (NULL != client->driver->command) {

                        up(&adap->clist_lock);

                        client->driver->command(client,cmd,arg);

                        down(&adap->clist_lock);

                }

                module_put(client->driver->owner);

       }

       up(&adap->clist_lock);

}

/* match always succeeds, as we want the probe() to tell if we really accept this match */

static int i2c_device_match(struct device *dev, struct device_driver *drv)

{

        return 1;

}

struct bus_type i2c_bus_type = {

        .name =         "i2c",

        .match =        i2c_device_match,

};

static int __init i2c_init(void)

{

        int retval;

        retval = bus_register(&i2c_bus_type);

        if (retval)

                return retval;

        retval = driver_register(&i2c_adapter_driver);

        if (retval)

                return retval;

        return class_register(&i2c_adapter_class);

}

static void __exit i2c_exit(void)

{

        class_unregister(&i2c_adapter_class);

        driver_unregister(&i2c_adapter_driver);

        bus_unregister(&i2c_bus_type);

}

subsys_initcall(i2c_init);

module_exit(i2c_exit);

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

 * the functional interface to the i2c busses.

 * ----------------------------------------------------

 */

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

{

        int ret;

        if (adap->algo->master_xfer) {

                DEB2(dev_dbg(&adap->dev, "master_xfer: with %d msgs.\n", num));

                down(&adap->bus_lock);

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

                up(&adap->bus_lock);

                return ret;

        } else {

                DEB2(dev_dbg(&adap->dev, "I2C level transfers not supported\n"));

                return -ENOSYS;

        }

}

int i2c_master_send(struct i2c_client *client,const char *buf ,int count)

{

        int ret;

        struct i2c_adapter *adap=client->adapter;

        struct i2c_msg msg;

        if (client->adapter->algo->master_xfer) {

                msg.addr   = client->addr;

                msg.flags = client->flags & I2C_M_TEN;

                msg.len = count;

                msg.buf = (char *)buf;

                DEB2(dev_dbg(&client->adapter->dev, "master_send: writing %d bytes.\n",

                                count));

                down(&adap->bus_lock);

                ret = adap->algo->master_xfer(adap,&msg,1);

                up(&adap->bus_lock);

                /* if everything went ok (i.e. 1 msg transmitted), return #bytes

                 * transmitted, else error code.

                 */

                return (ret == 1 )? count : ret;

        } else {

                dev_err(&client->adapter->dev, "I2C level transfers not supported\n");

                return -ENOSYS;

        }

}

int i2c_master_recv(struct i2c_client *client, char *buf ,int count)

{

        struct i2c_adapter *adap=client->adapter;

        struct i2c_msg msg;

        int ret;

        if (client->adapter->algo->master_xfer) {

                msg.addr   = client->addr;

                msg.flags = client->flags & I2C_M_TEN;

                msg.flags |= I2C_M_RD;

                msg.len = count;

                msg.buf = buf;

                DEB2(dev_dbg(&client->adapter->dev, "master_recv: reading %d bytes.\n",

                                count));

                down(&adap->bus_lock);

                ret = adap->algo->master_xfer(adap,&msg,1);

                up(&adap->bus_lock);

                DEB2(printk(KERN_DEBUG "i2c-core.o: master_recv: return:%d (count:%d, addr:0x%02x)\n",

                        ret, count, client->addr));

                /* if everything went ok (i.e. 1 msg transmitted), return #bytes

                * transmitted, else error code.

                */

                return (ret == 1 )? count : ret;

        } else {

                dev_err(&client->adapter->dev, "I2C level transfers not supported\n");

                return -ENOSYS;

        }

}

int i2c_control(struct i2c_client *client,

        unsigned int cmd, unsigned long arg)

{

        int ret = 0;

        struct i2c_adapter *adap = client->adapter;

        DEB2(printk(KERN_DEBUG "i2c-core.o: i2c ioctl, cmd: 0x%x, arg: %#lx\n", cmd, arg));

        switch ( cmd ) {

                case I2C_RETRIES:

                        adap->retries = arg;

                        break;

                case I2C_TIMEOUT:

                        adap->timeout = arg;

                        break;

                default:

                        if (adap->algo->algo_control!=NULL)

                                ret = adap->algo->algo_control(adap,cmd,arg);

        }

        return ret;

}

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

 * the i2c address scanning function

 * Will not work for 10-bit addresses!

 * ----------------------------------------------------

 */

int i2c_probe(struct i2c_adapter *adapter,

              struct i2c_client_address_data *address_data,

              int (*found_proc) (struct i2c_adapter *, int, int))

{

        int addr,i,found,err;

        int adap_id = i2c_adapter_id(adapter);

        /* Forget it if we can't probe using SMBUS_QUICK */

        if (! i2c_check_functionality(adapter,I2C_FUNC_SMBUS_QUICK))

                return -1;

        for (addr = 0x00; addr <= 0x7f; addr++) {

                /* Skip if already in use */

                if (i2c_check_addr(adapter,addr))

                        continue;

                /* If it is in one of the force entries, we don't do any detection

                   at all */

                found = 0;

                for (i = 0; !found && (address_data->force[i] != I2C_CLIENT_END); i += 3) {

                        if (((adap_id == address_data->force[i]) ||

                             (address_data->force[i] == ANY_I2C_BUS)) &&

                             (addr == address_data->force[i+1])) {

                                DEB2(printk(KERN_DEBUG "i2c-core.o: found force parameter for adapter %d, addr %04x\n",

                                            adap_id,addr));

                                if ((err = found_proc(adapter,addr,0)))

                                        return err;

                                found = 1;

                        }

                }

                if (found)

                        continue;

                /* If this address is in one of the ignores, we can forget about

                   it right now */

                for (i = 0;

                     !found && (address_data->ignore[i] != I2C_CLIENT_END);

                     i += 2) {

                        if (((adap_id == address_data->ignore[i]) ||

                            ((address_data->ignore[i] == ANY_I2C_BUS))) &&

                            (addr == address_data->ignore[i+1])) {

                                DEB2(printk(KERN_DEBUG "i2c-core.o: found ignore parameter for adapter %d, "

                                     "addr %04x\n", adap_id ,addr));

                                found = 1;

                        }

                }

                for (i = 0;

                     !found && (address_data->ignore_range[i] != I2C_CLIENT_END);

                     i += 3) {

                        if (((adap_id == address_data->ignore_range[i]) ||

                            ((address_data->ignore_range[i]==ANY_I2C_BUS))) &&

                            (addr >= address_data->ignore_range[i+1]) &&

                            (addr <= address_data->ignore_range[i+2])) {

                                DEB2(printk(KERN_DEBUG "i2c-core.o: found ignore_range parameter for adapter %d, "

                                            "addr %04x\n", adap_id,addr));

                                found = 1;

                        }

                }

                if (found)

                        continue;

                /* Now, we will do a detection, but only if it is in the normal or

                   probe entries */  

                for (i = 0;

                     !found && (address_data->normal_i2c[i] != I2C_CLIENT_END);

                     i += 1) {

                        if (addr == address_data->normal_i2c[i]) {

                                found = 1;

                                DEB2(printk(KERN_DEBUG "i2c-core.o: found normal i2c entry for adapter %d, "

                                            "addr %02x", adap_id,addr));

                        }

                }

                for (i = 0;

                     !found && (address_data->normal_i2c_range[i] != I2C_CLIENT_END);

                     i += 2) {

                        if ((addr >= address_data->normal_i2c_range[i]) &&

                            (addr <= address_data->normal_i2c_range[i+1])) {

                                found = 1;

                                DEB2(printk(KERN_DEBUG "i2c-core.o: found normal i2c_range entry for adapter %d, "

                                            "addr %04x\n", adap_id,addr));

                        }

                }

                for (i = 0;

                     !found && (address_data->probe[i] != I2C_CLIENT_END);

                     i += 2) {

                        if (((adap_id == address_data->probe[i]) ||

                            ((address_data->probe[i] == ANY_I2C_BUS))) &&

                            (addr == address_data->probe[i+1])) {

                                found = 1;

                                DEB2(printk(KERN_DEBUG "i2c-core.o: found probe parameter for adapter %d, "

                                            "addr %04x\n", adap_id,addr));

                        }

                }

                for (i = 0;

                     !found && (address_data->probe_range[i] != I2C_CLIENT_END);

                     i += 3) {

                        if (((adap_id == address_data->probe_range[i]) ||

                           (address_data->probe_range[i] == ANY_I2C_BUS)) &&

                           (addr >= address_data->probe_range[i+1]) &&

                           (addr <= address_data->probe_range[i+2])) {

                                found = 1;

                                DEB2(printk(KERN_DEBUG "i2c-core.o: found probe_range parameter for adapter %d, "

                                            "addr %04x\n", adap_id,addr));

                        }

                }

                if (!found)

                        continue;

                /* OK, so we really should examine this address. First check

                   whether there is some client here at all! */

                if (i2c_smbus_xfer(adapter,addr,0,0,0,I2C_SMBUS_QUICK,NULL) >= 0)

                        if ((err = found_proc(adapter,addr,-1)))

                                return err;

        }

        return 0;

}

/*

 * return id number for a specific adapter

 */

int i2c_adapter_id(struct i2c_adapter *adap)

{

        return adap->nr;

}