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linux/drivers/i2c/i2c-core.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2 
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

1273 lines
33 KiB
C
Raw Blame History

/* 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> */
#include <linux/config.h>
#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/idr.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
static LIST_HEAD(adapters);
static LIST_HEAD(drivers);
static DECLARE_MUTEX(core_lists);
static DEFINE_IDR(i2c_adapter_idr);
/* 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;
}
static int i2c_bus_suspend(struct device * dev, pm_message_t state)
{
int rc = 0;
if (dev->driver && dev->driver->suspend)
rc = dev->driver->suspend(dev,state,0);
return rc;
}
static int i2c_bus_resume(struct device * dev)
{
int rc = 0;
if (dev->driver && dev->driver->resume)
rc = dev->driver->resume(dev,0);
return rc;
}
static struct bus_type i2c_bus_type = {
.name = "i2c",
.match = i2c_device_match,
.suspend = i2c_bus_suspend,
.resume = i2c_bus_resume,
};
static int i2c_device_probe(struct device *dev)
{
return -ENODEV;
}
static 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)
{
int id, res = 0;
struct list_head *item;
struct i2c_driver *driver;
down(&core_lists);
if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) {
res = -ENOMEM;
goto out_unlock;
}
res = idr_get_new(&i2c_adapter_idr, NULL, &id);
if (res < 0) {
if (res == -EAGAIN)
res = -ENOMEM;
goto out_unlock;
}
adap->nr = id & MAX_ID_MASK;
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 host bus.
*/
if (adap->dev.parent == NULL)
adap->dev.parent = &platform_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);
}
dev_dbg(&adap->dev, "registered as adapter #%d\n", adap->nr);
out_unlock:
up(&core_lists);
return res;
}
int i2c_del_adapter(struct i2c_adapter *adap)
{
struct list_head *item, *_n;
struct i2c_adapter *adap_from_list;
struct i2c_driver *driver;
struct i2c_client *client;
int res = 0;
down(&core_lists);
/* First make sure that this adapter was ever added */
list_for_each_entry(adap_from_list, &adapters, list) {
if (adap_from_list == adap)
break;
}
if (adap_from_list != adap) {
pr_debug("I2C: Attempting to delete an unregistered "
"adapter\n");
res = -EINVAL;
goto out_unlock;
}
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);
/* free dynamically allocated bus id */
idr_remove(&i2c_adapter_idr, adap->nr);
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);
pr_debug("i2c-core: 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.
*/
pr_debug("i2c-core: 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);
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;
pr_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);
pr_debug("i2c-core: 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);
}
}
dev_dbg(&adapter->dev, "client [%s] registered to adapter\n",
client->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);
pr_debug("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) {
dev_err(&client->dev,
"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)
{
int ret;
ret = i2c_inc_use_client(client);
if (ret)
return ret;
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 {
pr_debug("i2c-core: %s used one too many times\n",
__FUNCTION__);
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);
}
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) {
#ifdef DEBUG
for (ret = 0; ret < num; ret++) {
dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
"len=%d\n", ret, msgs[ret].flags & I2C_M_RD ?
'R' : 'W', msgs[ret].addr, msgs[ret].len);
}
#endif
down(&adap->bus_lock);
ret = adap->algo->master_xfer(adap,msgs,num);
up(&adap->bus_lock);
return ret;
} else {
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;
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;
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);
dev_dbg(&client->adapter->dev, "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;
dev_dbg(&client->adapter->dev, "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 += 2) {
if (((adap_id == address_data->force[i]) ||
(address_data->force[i] == ANY_I2C_BUS)) &&
(addr == address_data->force[i+1])) {
dev_dbg(&adapter->dev, "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])) {
dev_dbg(&adapter->dev, "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])) {
dev_dbg(&adapter->dev, "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;
dev_dbg(&adapter->dev, "found normal i2c entry for adapter %d, "
"addr %02x\n", 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;
dev_dbg(&adapter->dev, "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;
dev_dbg(&adapter->dev, "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;
dev_dbg(&adapter->dev, "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;
}
struct i2c_adapter* i2c_get_adapter(int id)
{
struct list_head *item;
struct i2c_adapter *adapter;
down(&core_lists);
list_for_each(item,&adapters) {
adapter = list_entry(item, struct i2c_adapter, list);
if (id == adapter->nr &&
try_module_get(adapter->owner)) {
up(&core_lists);
return adapter;
}
}
up(&core_lists);
return NULL;
}
void i2c_put_adapter(struct i2c_adapter *adap)
{
module_put(adap->owner);
}
/* The SMBus parts */
#define POLY (0x1070U << 3)
static u8
crc8(u16 data)
{
int i;
for(i = 0; i < 8; i++) {
if (data & 0x8000)
data = data ^ POLY;
data = data << 1;
}
return (u8)(data >> 8);
}
/* CRC over count bytes in the first array plus the bytes in the rest
array if it is non-null. rest[0] is the (length of rest) - 1
and is included. */
static u8 i2c_smbus_partial_pec(u8 crc, int count, u8 *first, u8 *rest)
{
int i;
for(i = 0; i < count; i++)
crc = crc8((crc ^ first[i]) << 8);
if(rest != NULL)
for(i = 0; i <= rest[0]; i++)
crc = crc8((crc ^ rest[i]) << 8);
return crc;
}
static u8 i2c_smbus_pec(int count, u8 *first, u8 *rest)
{
return i2c_smbus_partial_pec(0, count, first, rest);
}
/* Returns new "size" (transaction type)
Note that we convert byte to byte_data and byte_data to word_data
rather than invent new xxx_PEC transactions. */
static int i2c_smbus_add_pec(u16 addr, u8 command, int size,
union i2c_smbus_data *data)
{
u8 buf[3];
buf[0] = addr << 1;
buf[1] = command;
switch(size) {
case I2C_SMBUS_BYTE:
data->byte = i2c_smbus_pec(2, buf, NULL);
size = I2C_SMBUS_BYTE_DATA;
break;
case I2C_SMBUS_BYTE_DATA:
buf[2] = data->byte;
data->word = buf[2] ||
(i2c_smbus_pec(3, buf, NULL) << 8);
size = I2C_SMBUS_WORD_DATA;
break;
case I2C_SMBUS_WORD_DATA:
/* unsupported */
break;
case I2C_SMBUS_BLOCK_DATA:
data->block[data->block[0] + 1] =
i2c_smbus_pec(2, buf, data->block);
size = I2C_SMBUS_BLOCK_DATA_PEC;
break;
}
return size;
}
static int i2c_smbus_check_pec(u16 addr, u8 command, int size, u8 partial,
union i2c_smbus_data *data)
{
u8 buf[3], rpec, cpec;
buf[1] = command;
switch(size) {
case I2C_SMBUS_BYTE_DATA:
buf[0] = (addr << 1) | 1;
cpec = i2c_smbus_pec(2, buf, NULL);
rpec = data->byte;
break;
case I2C_SMBUS_WORD_DATA:
buf[0] = (addr << 1) | 1;
buf[2] = data->word & 0xff;
cpec = i2c_smbus_pec(3, buf, NULL);
rpec = data->word >> 8;
break;
case I2C_SMBUS_WORD_DATA_PEC:
/* unsupported */
cpec = rpec = 0;
break;
case I2C_SMBUS_PROC_CALL_PEC:
/* unsupported */
cpec = rpec = 0;
break;
case I2C_SMBUS_BLOCK_DATA_PEC:
buf[0] = (addr << 1);
buf[2] = (addr << 1) | 1;
cpec = i2c_smbus_pec(3, buf, data->block);
rpec = data->block[data->block[0] + 1];
break;
case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
buf[0] = (addr << 1) | 1;
rpec = i2c_smbus_partial_pec(partial, 1,
buf, data->block);
cpec = data->block[data->block[0] + 1];
break;
default:
cpec = rpec = 0;
break;
}
if (rpec != cpec) {
pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
rpec, cpec);
return -1;
}
return 0;
}
s32 i2c_smbus_write_quick(struct i2c_client *client, u8 value)
{
return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
value,0,I2C_SMBUS_QUICK,NULL);
}
s32 i2c_smbus_read_byte(struct i2c_client *client)
{
union i2c_smbus_data data;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,0,I2C_SMBUS_BYTE, &data))
return -1;
else
return 0x0FF & data.byte;
}
s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
{
union i2c_smbus_data data; /* only for PEC */
return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_WRITE,value, I2C_SMBUS_BYTE,&data);
}
s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
{
union i2c_smbus_data data;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,command, I2C_SMBUS_BYTE_DATA,&data))
return -1;
else
return 0x0FF & data.byte;
}
s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
{
union i2c_smbus_data data;
data.byte = value;
return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_WRITE,command,
I2C_SMBUS_BYTE_DATA,&data);
}
s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
{
union i2c_smbus_data data;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,command, I2C_SMBUS_WORD_DATA, &data))
return -1;
else
return 0x0FFFF & data.word;
}
s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
{
union i2c_smbus_data data;
data.word = value;
return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_WRITE,command,
I2C_SMBUS_WORD_DATA,&data);
}
s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
u8 length, u8 *values)
{
union i2c_smbus_data data;
int i;
if (length > I2C_SMBUS_BLOCK_MAX)
length = I2C_SMBUS_BLOCK_MAX;
for (i = 1; i <= length; i++)
data.block[i] = values[i-1];
data.block[0] = length;
return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_WRITE,command,
I2C_SMBUS_BLOCK_DATA,&data);
}
/* Returns the number of read bytes */
s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command, u8 *values)
{
union i2c_smbus_data data;
int i;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,command,
I2C_SMBUS_I2C_BLOCK_DATA,&data))
return -1;
else {
for (i = 1; i <= data.block[0]; i++)
values[i-1] = data.block[i];
return data.block[0];
}
}
/* Simulate a SMBus command using the i2c protocol
No checking of parameters is done! */
static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
unsigned short flags,
char read_write, u8 command, int size,
union i2c_smbus_data * data)
{
/* So we need to generate a series of msgs. In the case of writing, we
need to use only one message; when reading, we need two. We initialize
most things with sane defaults, to keep the code below somewhat
simpler. */
unsigned char msgbuf0[34];
unsigned char msgbuf1[34];
int num = read_write == I2C_SMBUS_READ?2:1;
struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
{ addr, flags | I2C_M_RD, 0, msgbuf1 }
};
int i;
msgbuf0[0] = command;
switch(size) {
case I2C_SMBUS_QUICK:
msg[0].len = 0;
/* Special case: The read/write field is used as data */
msg[0].flags = flags | (read_write==I2C_SMBUS_READ)?I2C_M_RD:0;
num = 1;
break;
case I2C_SMBUS_BYTE:
if (read_write == I2C_SMBUS_READ) {
/* Special case: only a read! */
msg[0].flags = I2C_M_RD | flags;
num = 1;
}
break;
case I2C_SMBUS_BYTE_DATA:
if (read_write == I2C_SMBUS_READ)
msg[1].len = 1;
else {
msg[0].len = 2;
msgbuf0[1] = data->byte;
}
break;
case I2C_SMBUS_WORD_DATA:
if (read_write == I2C_SMBUS_READ)
msg[1].len = 2;
else {
msg[0].len=3;
msgbuf0[1] = data->word & 0xff;
msgbuf0[2] = (data->word >> 8) & 0xff;
}
break;
case I2C_SMBUS_PROC_CALL:
num = 2; /* Special case */
read_write = I2C_SMBUS_READ;
msg[0].len = 3;
msg[1].len = 2;
msgbuf0[1] = data->word & 0xff;
msgbuf0[2] = (data->word >> 8) & 0xff;
break;
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_BLOCK_DATA_PEC:
if (read_write == I2C_SMBUS_READ) {
dev_err(&adapter->dev, "Block read not supported "
"under I2C emulation!\n");
return -1;
} else {
msg[0].len = data->block[0] + 2;
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
dev_err(&adapter->dev, "smbus_access called with "
"invalid block write size (%d)\n",
data->block[0]);
return -1;
}
if(size == I2C_SMBUS_BLOCK_DATA_PEC)
(msg[0].len)++;
for (i = 1; i <= msg[0].len; i++)
msgbuf0[i] = data->block[i-1];
}
break;
case I2C_SMBUS_BLOCK_PROC_CALL:
case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
dev_dbg(&adapter->dev, "Block process call not supported "
"under I2C emulation!\n");
return -1;
case I2C_SMBUS_I2C_BLOCK_DATA:
if (read_write == I2C_SMBUS_READ) {
msg[1].len = I2C_SMBUS_I2C_BLOCK_MAX;
} else {
msg[0].len = data->block[0] + 1;
if (msg[0].len > I2C_SMBUS_I2C_BLOCK_MAX + 1) {
dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with "
"invalid block write size (%d)\n",
data->block[0]);
return -1;
}
for (i = 1; i <= data->block[0]; i++)
msgbuf0[i] = data->block[i];
}
break;
default:
dev_err(&adapter->dev, "smbus_access called with invalid size (%d)\n",
size);
return -1;
}
if (i2c_transfer(adapter, msg, num) < 0)
return -1;
if (read_write == I2C_SMBUS_READ)
switch(size) {
case I2C_SMBUS_BYTE:
data->byte = msgbuf0[0];
break;
case I2C_SMBUS_BYTE_DATA:
data->byte = msgbuf1[0];
break;
case I2C_SMBUS_WORD_DATA:
case I2C_SMBUS_PROC_CALL:
data->word = msgbuf1[0] | (msgbuf1[1] << 8);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
/* fixed at 32 for now */
data->block[0] = I2C_SMBUS_I2C_BLOCK_MAX;
for (i = 0; i < I2C_SMBUS_I2C_BLOCK_MAX; i++)
data->block[i+1] = msgbuf1[i];
break;
}
return 0;
}
s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
char read_write, u8 command, int size,
union i2c_smbus_data * data)
{
s32 res;
int swpec = 0;
u8 partial = 0;
flags &= I2C_M_TEN | I2C_CLIENT_PEC;
if((flags & I2C_CLIENT_PEC) &&
!(i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HWPEC_CALC))) {
swpec = 1;
if(read_write == I2C_SMBUS_READ &&
size == I2C_SMBUS_BLOCK_DATA)
size = I2C_SMBUS_BLOCK_DATA_PEC;
else if(size == I2C_SMBUS_PROC_CALL)
size = I2C_SMBUS_PROC_CALL_PEC;
else if(size == I2C_SMBUS_BLOCK_PROC_CALL) {
i2c_smbus_add_pec(addr, command,
I2C_SMBUS_BLOCK_DATA, data);
partial = data->block[data->block[0] + 1];
size = I2C_SMBUS_BLOCK_PROC_CALL_PEC;
} else if(read_write == I2C_SMBUS_WRITE &&
size != I2C_SMBUS_QUICK &&
size != I2C_SMBUS_I2C_BLOCK_DATA)
size = i2c_smbus_add_pec(addr, command, size, data);
}
if (adapter->algo->smbus_xfer) {
down(&adapter->bus_lock);
res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write,
command,size,data);
up(&adapter->bus_lock);
} else
res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
command,size,data);
if(res >= 0 && swpec &&
size != I2C_SMBUS_QUICK && size != I2C_SMBUS_I2C_BLOCK_DATA &&
(read_write == I2C_SMBUS_READ || size == I2C_SMBUS_PROC_CALL_PEC ||
size == I2C_SMBUS_BLOCK_PROC_CALL_PEC)) {
if(i2c_smbus_check_pec(addr, command, size, partial, data))
return -1;
}
return res;
}
EXPORT_SYMBOL(i2c_add_adapter);
EXPORT_SYMBOL(i2c_del_adapter);
EXPORT_SYMBOL(i2c_add_driver);
EXPORT_SYMBOL(i2c_del_driver);
EXPORT_SYMBOL(i2c_attach_client);
EXPORT_SYMBOL(i2c_detach_client);
EXPORT_SYMBOL(i2c_use_client);
EXPORT_SYMBOL(i2c_release_client);
EXPORT_SYMBOL(i2c_clients_command);
EXPORT_SYMBOL(i2c_check_addr);
EXPORT_SYMBOL(i2c_master_send);
EXPORT_SYMBOL(i2c_master_recv);
EXPORT_SYMBOL(i2c_control);
EXPORT_SYMBOL(i2c_transfer);
EXPORT_SYMBOL(i2c_adapter_id);
EXPORT_SYMBOL(i2c_get_adapter);
EXPORT_SYMBOL(i2c_put_adapter);
EXPORT_SYMBOL(i2c_probe);
EXPORT_SYMBOL(i2c_smbus_xfer);
EXPORT_SYMBOL(i2c_smbus_write_quick);
EXPORT_SYMBOL(i2c_smbus_read_byte);
EXPORT_SYMBOL(i2c_smbus_write_byte);
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
EXPORT_SYMBOL(i2c_smbus_read_word_data);
EXPORT_SYMBOL(i2c_smbus_write_word_data);
EXPORT_SYMBOL(i2c_smbus_write_block_data);
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");
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