1166 lines
30 KiB
C
1166 lines
30 KiB
C
/* i2c-core.c - a device driver for the iic-bus interface */
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/* ------------------------------------------------------------------------- */
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/* Copyright (C) 1995-99 Simon G. Vogl
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* ------------------------------------------------------------------------- */
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/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
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All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
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SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
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Jean Delvare <khali@linux-fr.org> */
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/idr.h>
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#include <linux/seq_file.h>
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#include <linux/platform_device.h>
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#include <asm/uaccess.h>
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static LIST_HEAD(adapters);
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static LIST_HEAD(drivers);
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static DECLARE_MUTEX(core_lists);
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static DEFINE_IDR(i2c_adapter_idr);
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/* match always succeeds, as we want the probe() to tell if we really accept this match */
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static int i2c_device_match(struct device *dev, struct device_driver *drv)
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{
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return 1;
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}
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static int i2c_bus_suspend(struct device * dev, pm_message_t state)
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{
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int rc = 0;
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if (dev->driver && dev->driver->suspend)
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rc = dev->driver->suspend(dev, state);
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return rc;
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}
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static int i2c_bus_resume(struct device * dev)
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{
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int rc = 0;
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if (dev->driver && dev->driver->resume)
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rc = dev->driver->resume(dev);
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return rc;
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}
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struct bus_type i2c_bus_type = {
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.name = "i2c",
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.match = i2c_device_match,
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.suspend = i2c_bus_suspend,
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.resume = i2c_bus_resume,
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};
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static int i2c_device_probe(struct device *dev)
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{
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return -ENODEV;
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}
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static int i2c_device_remove(struct device *dev)
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{
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return 0;
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}
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void i2c_adapter_dev_release(struct device *dev)
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{
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struct i2c_adapter *adap = dev_to_i2c_adapter(dev);
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complete(&adap->dev_released);
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}
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struct device_driver i2c_adapter_driver = {
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.owner = THIS_MODULE,
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.name = "i2c_adapter",
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.bus = &i2c_bus_type,
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.probe = i2c_device_probe,
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.remove = i2c_device_remove,
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};
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static void i2c_adapter_class_dev_release(struct class_device *dev)
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{
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struct i2c_adapter *adap = class_dev_to_i2c_adapter(dev);
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complete(&adap->class_dev_released);
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}
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struct class i2c_adapter_class = {
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.owner = THIS_MODULE,
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.name = "i2c-adapter",
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.release = &i2c_adapter_class_dev_release,
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};
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static ssize_t show_adapter_name(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct i2c_adapter *adap = dev_to_i2c_adapter(dev);
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return sprintf(buf, "%s\n", adap->name);
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}
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static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
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static void i2c_client_release(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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complete(&client->released);
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}
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static ssize_t show_client_name(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct i2c_client *client = to_i2c_client(dev);
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return sprintf(buf, "%s\n", client->name);
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}
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/*
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* We can't use the DEVICE_ATTR() macro here as we want the same filename for a
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* different type of a device. So beware if the DEVICE_ATTR() macro ever
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* changes, this definition will also have to change.
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*/
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static struct device_attribute dev_attr_client_name = {
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.attr = {.name = "name", .mode = S_IRUGO, .owner = THIS_MODULE },
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.show = &show_client_name,
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};
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/* ---------------------------------------------------
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* registering functions
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* ---------------------------------------------------
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*/
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/* -----
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* i2c_add_adapter is called from within the algorithm layer,
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* when a new hw adapter registers. A new device is register to be
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* available for clients.
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*/
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int i2c_add_adapter(struct i2c_adapter *adap)
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{
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int id, res = 0;
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struct list_head *item;
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struct i2c_driver *driver;
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down(&core_lists);
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if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) {
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res = -ENOMEM;
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goto out_unlock;
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}
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res = idr_get_new(&i2c_adapter_idr, adap, &id);
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if (res < 0) {
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if (res == -EAGAIN)
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res = -ENOMEM;
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goto out_unlock;
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}
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adap->nr = id & MAX_ID_MASK;
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init_MUTEX(&adap->bus_lock);
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init_MUTEX(&adap->clist_lock);
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list_add_tail(&adap->list,&adapters);
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INIT_LIST_HEAD(&adap->clients);
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/* Add the adapter to the driver core.
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* If the parent pointer is not set up,
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* we add this adapter to the host bus.
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*/
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if (adap->dev.parent == NULL)
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adap->dev.parent = &platform_bus;
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sprintf(adap->dev.bus_id, "i2c-%d", adap->nr);
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adap->dev.driver = &i2c_adapter_driver;
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adap->dev.release = &i2c_adapter_dev_release;
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device_register(&adap->dev);
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device_create_file(&adap->dev, &dev_attr_name);
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/* Add this adapter to the i2c_adapter class */
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memset(&adap->class_dev, 0x00, sizeof(struct class_device));
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adap->class_dev.dev = &adap->dev;
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adap->class_dev.class = &i2c_adapter_class;
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strlcpy(adap->class_dev.class_id, adap->dev.bus_id, BUS_ID_SIZE);
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class_device_register(&adap->class_dev);
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dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
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/* inform drivers of new adapters */
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list_for_each(item,&drivers) {
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driver = list_entry(item, struct i2c_driver, list);
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if (driver->attach_adapter)
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/* We ignore the return code; if it fails, too bad */
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driver->attach_adapter(adap);
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}
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out_unlock:
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up(&core_lists);
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return res;
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}
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int i2c_del_adapter(struct i2c_adapter *adap)
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{
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struct list_head *item, *_n;
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struct i2c_adapter *adap_from_list;
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struct i2c_driver *driver;
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struct i2c_client *client;
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int res = 0;
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down(&core_lists);
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/* First make sure that this adapter was ever added */
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list_for_each_entry(adap_from_list, &adapters, list) {
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if (adap_from_list == adap)
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break;
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}
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if (adap_from_list != adap) {
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pr_debug("i2c-core: attempting to delete unregistered "
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"adapter [%s]\n", adap->name);
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res = -EINVAL;
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goto out_unlock;
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}
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list_for_each(item,&drivers) {
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driver = list_entry(item, struct i2c_driver, list);
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if (driver->detach_adapter)
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if ((res = driver->detach_adapter(adap))) {
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dev_err(&adap->dev, "detach_adapter failed "
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"for driver [%s]\n", driver->name);
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goto out_unlock;
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}
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}
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/* detach any active clients. This must be done first, because
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* it can fail; in which case we give up. */
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list_for_each_safe(item, _n, &adap->clients) {
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client = list_entry(item, struct i2c_client, list);
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/* detaching devices is unconditional of the set notify
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* flag, as _all_ clients that reside on the adapter
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* must be deleted, as this would cause invalid states.
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*/
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if ((res=client->driver->detach_client(client))) {
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dev_err(&adap->dev, "detach_client failed for client "
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"[%s] at address 0x%02x\n", client->name,
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client->addr);
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goto out_unlock;
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}
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}
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/* clean up the sysfs representation */
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init_completion(&adap->dev_released);
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init_completion(&adap->class_dev_released);
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class_device_unregister(&adap->class_dev);
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device_remove_file(&adap->dev, &dev_attr_name);
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device_unregister(&adap->dev);
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list_del(&adap->list);
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/* wait for sysfs to drop all references */
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wait_for_completion(&adap->dev_released);
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wait_for_completion(&adap->class_dev_released);
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/* free dynamically allocated bus id */
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idr_remove(&i2c_adapter_idr, adap->nr);
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dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
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out_unlock:
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up(&core_lists);
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return res;
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}
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/* -----
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* What follows is the "upwards" interface: commands for talking to clients,
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* which implement the functions to access the physical information of the
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* chips.
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*/
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int i2c_add_driver(struct i2c_driver *driver)
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{
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struct list_head *item;
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struct i2c_adapter *adapter;
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int res = 0;
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down(&core_lists);
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/* add the driver to the list of i2c drivers in the driver core */
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driver->driver.owner = driver->owner;
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driver->driver.name = driver->name;
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driver->driver.bus = &i2c_bus_type;
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driver->driver.probe = i2c_device_probe;
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driver->driver.remove = i2c_device_remove;
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res = driver_register(&driver->driver);
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if (res)
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goto out_unlock;
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list_add_tail(&driver->list,&drivers);
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pr_debug("i2c-core: driver [%s] registered\n", driver->name);
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/* now look for instances of driver on our adapters */
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if (driver->attach_adapter) {
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list_for_each(item,&adapters) {
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adapter = list_entry(item, struct i2c_adapter, list);
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driver->attach_adapter(adapter);
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}
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}
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out_unlock:
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up(&core_lists);
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return res;
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}
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int i2c_del_driver(struct i2c_driver *driver)
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{
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struct list_head *item1, *item2, *_n;
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struct i2c_client *client;
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struct i2c_adapter *adap;
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int res = 0;
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down(&core_lists);
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/* Have a look at each adapter, if clients of this driver are still
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* attached. If so, detach them to be able to kill the driver
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* afterwards.
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*
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* Removing clients does not depend on the notify flag, else
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* invalid operation might (will!) result, when using stale client
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* pointers.
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*/
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list_for_each(item1,&adapters) {
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adap = list_entry(item1, struct i2c_adapter, list);
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if (driver->detach_adapter) {
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if ((res = driver->detach_adapter(adap))) {
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dev_err(&adap->dev, "detach_adapter failed "
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"for driver [%s]\n", driver->name);
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goto out_unlock;
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}
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} else {
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list_for_each_safe(item2, _n, &adap->clients) {
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client = list_entry(item2, struct i2c_client, list);
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if (client->driver != driver)
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continue;
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dev_dbg(&adap->dev, "detaching client [%s] "
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"at 0x%02x\n", client->name,
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client->addr);
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if ((res = driver->detach_client(client))) {
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dev_err(&adap->dev, "detach_client "
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"failed for client [%s] at "
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"0x%02x\n", client->name,
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client->addr);
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goto out_unlock;
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}
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}
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}
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}
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driver_unregister(&driver->driver);
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list_del(&driver->list);
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pr_debug("i2c-core: driver [%s] unregistered\n", driver->name);
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out_unlock:
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up(&core_lists);
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return 0;
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}
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static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr)
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{
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struct list_head *item;
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struct i2c_client *client;
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list_for_each(item,&adapter->clients) {
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client = list_entry(item, struct i2c_client, list);
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if (client->addr == addr)
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return -EBUSY;
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}
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return 0;
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}
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int i2c_check_addr(struct i2c_adapter *adapter, int addr)
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{
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int rval;
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down(&adapter->clist_lock);
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rval = __i2c_check_addr(adapter, addr);
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up(&adapter->clist_lock);
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return rval;
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}
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int i2c_attach_client(struct i2c_client *client)
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{
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struct i2c_adapter *adapter = client->adapter;
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down(&adapter->clist_lock);
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if (__i2c_check_addr(client->adapter, client->addr)) {
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up(&adapter->clist_lock);
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return -EBUSY;
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}
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list_add_tail(&client->list,&adapter->clients);
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up(&adapter->clist_lock);
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if (adapter->client_register) {
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if (adapter->client_register(client)) {
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dev_dbg(&adapter->dev, "client_register "
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"failed for client [%s] at 0x%02x\n",
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client->name, client->addr);
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}
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}
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client->usage_count = 0;
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client->dev.parent = &client->adapter->dev;
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client->dev.driver = &client->driver->driver;
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client->dev.bus = &i2c_bus_type;
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client->dev.release = &i2c_client_release;
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snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id),
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"%d-%04x", i2c_adapter_id(adapter), client->addr);
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dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n",
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client->name, client->dev.bus_id);
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device_register(&client->dev);
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device_create_file(&client->dev, &dev_attr_client_name);
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return 0;
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}
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int i2c_detach_client(struct i2c_client *client)
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{
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struct i2c_adapter *adapter = client->adapter;
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int res = 0;
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if (client->usage_count > 0) {
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dev_warn(&client->dev, "Client [%s] still busy, "
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"can't detach\n", client->name);
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return -EBUSY;
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}
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|
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if (adapter->client_unregister) {
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res = adapter->client_unregister(client);
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if (res) {
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dev_err(&client->dev,
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"client_unregister [%s] failed, "
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"client not detached\n", client->name);
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goto out;
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}
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}
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down(&adapter->clist_lock);
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list_del(&client->list);
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init_completion(&client->released);
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device_remove_file(&client->dev, &dev_attr_client_name);
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device_unregister(&client->dev);
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up(&adapter->clist_lock);
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wait_for_completion(&client->released);
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out:
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return res;
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}
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static int i2c_inc_use_client(struct i2c_client *client)
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{
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if (!try_module_get(client->driver->owner))
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return -ENODEV;
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if (!try_module_get(client->adapter->owner)) {
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module_put(client->driver->owner);
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return -ENODEV;
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}
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return 0;
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}
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static void i2c_dec_use_client(struct i2c_client *client)
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{
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module_put(client->driver->owner);
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module_put(client->adapter->owner);
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}
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int i2c_use_client(struct i2c_client *client)
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{
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int ret;
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ret = i2c_inc_use_client(client);
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if (ret)
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return ret;
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client->usage_count++;
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|
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return 0;
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}
|
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|
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int i2c_release_client(struct i2c_client *client)
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{
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if (!client->usage_count) {
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pr_debug("i2c-core: %s used one too many times\n",
|
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__FUNCTION__);
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return -EPERM;
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}
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|
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client->usage_count--;
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i2c_dec_use_client(client);
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return 0;
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}
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|
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void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
|
|
{
|
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struct list_head *item;
|
|
struct i2c_client *client;
|
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|
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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;
|
|
|
|
msg.addr = client->addr;
|
|
msg.flags = client->flags & I2C_M_TEN;
|
|
msg.len = count;
|
|
msg.buf = (char *)buf;
|
|
|
|
ret = i2c_transfer(adap, &msg, 1);
|
|
|
|
/* If everything went ok (i.e. 1 msg transmitted), return #bytes
|
|
transmitted, else error code. */
|
|
return (ret == 1) ? count : ret;
|
|
}
|
|
|
|
int i2c_master_recv(struct i2c_client *client, char *buf ,int count)
|
|
{
|
|
struct i2c_adapter *adap=client->adapter;
|
|
struct i2c_msg msg;
|
|
int ret;
|
|
|
|
msg.addr = client->addr;
|
|
msg.flags = client->flags & I2C_M_TEN;
|
|
msg.flags |= I2C_M_RD;
|
|
msg.len = count;
|
|
msg.buf = buf;
|
|
|
|
ret = i2c_transfer(adap, &msg, 1);
|
|
|
|
/* If everything went ok (i.e. 1 msg transmitted), return #bytes
|
|
transmitted, else error code. */
|
|
return (ret == 1) ? count : ret;
|
|
}
|
|
|
|
|
|
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!
|
|
* ----------------------------------------------------
|
|
*/
|
|
static int i2c_probe_address(struct i2c_adapter *adapter, int addr, int kind,
|
|
int (*found_proc) (struct i2c_adapter *, int, int))
|
|
{
|
|
int err;
|
|
|
|
/* Make sure the address is valid */
|
|
if (addr < 0x03 || addr > 0x77) {
|
|
dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
|
|
addr);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Skip if already in use */
|
|
if (i2c_check_addr(adapter, addr))
|
|
return 0;
|
|
|
|
/* Make sure there is something at this address, unless forced */
|
|
if (kind < 0) {
|
|
if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
|
|
I2C_SMBUS_QUICK, NULL) < 0)
|
|
return 0;
|
|
|
|
/* prevent 24RF08 corruption */
|
|
if ((addr & ~0x0f) == 0x50)
|
|
i2c_smbus_xfer(adapter, addr, 0, 0, 0,
|
|
I2C_SMBUS_QUICK, NULL);
|
|
}
|
|
|
|
/* Finally call the custom detection function */
|
|
err = found_proc(adapter, addr, kind);
|
|
|
|
/* -ENODEV can be returned if there is a chip at the given address
|
|
but it isn't supported by this chip driver. We catch it here as
|
|
this isn't an error. */
|
|
return (err == -ENODEV) ? 0 : err;
|
|
}
|
|
|
|
int i2c_probe(struct i2c_adapter *adapter,
|
|
struct i2c_client_address_data *address_data,
|
|
int (*found_proc) (struct i2c_adapter *, int, int))
|
|
{
|
|
int i, err;
|
|
int adap_id = i2c_adapter_id(adapter);
|
|
|
|
/* Force entries are done first, and are not affected by ignore
|
|
entries */
|
|
if (address_data->forces) {
|
|
unsigned short **forces = address_data->forces;
|
|
int kind;
|
|
|
|
for (kind = 0; forces[kind]; kind++) {
|
|
for (i = 0; forces[kind][i] != I2C_CLIENT_END;
|
|
i += 2) {
|
|
if (forces[kind][i] == adap_id
|
|
|| forces[kind][i] == ANY_I2C_BUS) {
|
|
dev_dbg(&adapter->dev, "found force "
|
|
"parameter for adapter %d, "
|
|
"addr 0x%02x, kind %d\n",
|
|
adap_id, forces[kind][i + 1],
|
|
kind);
|
|
err = i2c_probe_address(adapter,
|
|
forces[kind][i + 1],
|
|
kind, found_proc);
|
|
if (err)
|
|
return err;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Stop here if we can't use SMBUS_QUICK */
|
|
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
|
|
if (address_data->probe[0] == I2C_CLIENT_END
|
|
&& address_data->normal_i2c[0] == I2C_CLIENT_END)
|
|
return 0;
|
|
|
|
dev_warn(&adapter->dev, "SMBus Quick command not supported, "
|
|
"can't probe for chips\n");
|
|
return -1;
|
|
}
|
|
|
|
/* Probe entries are done second, and are not affected by ignore
|
|
entries either */
|
|
for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
|
|
if (address_data->probe[i] == adap_id
|
|
|| address_data->probe[i] == ANY_I2C_BUS) {
|
|
dev_dbg(&adapter->dev, "found probe parameter for "
|
|
"adapter %d, addr 0x%02x\n", adap_id,
|
|
address_data->probe[i + 1]);
|
|
err = i2c_probe_address(adapter,
|
|
address_data->probe[i + 1],
|
|
-1, found_proc);
|
|
if (err)
|
|
return err;
|
|
}
|
|
}
|
|
|
|
/* Normal entries are done last, unless shadowed by an ignore entry */
|
|
for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) {
|
|
int j, ignore;
|
|
|
|
ignore = 0;
|
|
for (j = 0; address_data->ignore[j] != I2C_CLIENT_END;
|
|
j += 2) {
|
|
if ((address_data->ignore[j] == adap_id ||
|
|
address_data->ignore[j] == ANY_I2C_BUS)
|
|
&& address_data->ignore[j + 1]
|
|
== address_data->normal_i2c[i]) {
|
|
dev_dbg(&adapter->dev, "found ignore "
|
|
"parameter for adapter %d, "
|
|
"addr 0x%02x\n", adap_id,
|
|
address_data->ignore[j + 1]);
|
|
}
|
|
ignore = 1;
|
|
break;
|
|
}
|
|
if (ignore)
|
|
continue;
|
|
|
|
dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
|
|
"addr 0x%02x\n", adap_id,
|
|
address_data->normal_i2c[i]);
|
|
err = i2c_probe_address(adapter, address_data->normal_i2c[i],
|
|
-1, found_proc);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct i2c_adapter* i2c_get_adapter(int id)
|
|
{
|
|
struct i2c_adapter *adapter;
|
|
|
|
down(&core_lists);
|
|
adapter = (struct i2c_adapter *)idr_find(&i2c_adapter_idr, id);
|
|
if (adapter && !try_module_get(adapter->owner))
|
|
adapter = NULL;
|
|
|
|
up(&core_lists);
|
|
return adapter;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
/* Incremental CRC8 over count bytes in the array pointed to by p */
|
|
static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
|
|
{
|
|
int i;
|
|
|
|
for(i = 0; i < count; i++)
|
|
crc = crc8((crc ^ p[i]) << 8);
|
|
return crc;
|
|
}
|
|
|
|
/* Assume a 7-bit address, which is reasonable for SMBus */
|
|
static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
|
|
{
|
|
/* The address will be sent first */
|
|
u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
|
|
pec = i2c_smbus_pec(pec, &addr, 1);
|
|
|
|
/* The data buffer follows */
|
|
return i2c_smbus_pec(pec, msg->buf, msg->len);
|
|
}
|
|
|
|
/* Used for write only transactions */
|
|
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
|
|
{
|
|
msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
|
|
msg->len++;
|
|
}
|
|
|
|
/* Return <0 on CRC error
|
|
If there was a write before this read (most cases) we need to take the
|
|
partial CRC from the write part into account.
|
|
Note that this function does modify the message (we need to decrease the
|
|
message length to hide the CRC byte from the caller). */
|
|
static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
|
|
{
|
|
u8 rpec = msg->buf[--msg->len];
|
|
cpec = i2c_smbus_msg_pec(cpec, msg);
|
|
|
|
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)
|
|
{
|
|
return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
|
|
I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
|
|
}
|
|
|
|
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[I2C_SMBUS_BLOCK_MAX+3];
|
|
unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
|
|
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;
|
|
u8 partial_pec = 0;
|
|
|
|
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:
|
|
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;
|
|
}
|
|
for (i = 1; i < msg[0].len; i++)
|
|
msgbuf0[i] = data->block[i-1];
|
|
}
|
|
break;
|
|
case I2C_SMBUS_BLOCK_PROC_CALL:
|
|
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_BLOCK_MAX;
|
|
} else {
|
|
msg[0].len = data->block[0] + 1;
|
|
if (msg[0].len > I2C_SMBUS_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;
|
|
}
|
|
|
|
i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
|
|
&& size != I2C_SMBUS_I2C_BLOCK_DATA);
|
|
if (i) {
|
|
/* Compute PEC if first message is a write */
|
|
if (!(msg[0].flags & I2C_M_RD)) {
|
|
if (num == 1) /* Write only */
|
|
i2c_smbus_add_pec(&msg[0]);
|
|
else /* Write followed by read */
|
|
partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
|
|
}
|
|
/* Ask for PEC if last message is a read */
|
|
if (msg[num-1].flags & I2C_M_RD)
|
|
msg[num-1].len++;
|
|
}
|
|
|
|
if (i2c_transfer(adapter, msg, num) < 0)
|
|
return -1;
|
|
|
|
/* Check PEC if last message is a read */
|
|
if (i && (msg[num-1].flags & I2C_M_RD)) {
|
|
if (i2c_smbus_check_pec(partial_pec, &msg[num-1]) < 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_BLOCK_MAX;
|
|
for (i = 0; i < I2C_SMBUS_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;
|
|
|
|
flags &= I2C_M_TEN | I2C_CLIENT_PEC;
|
|
|
|
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);
|
|
|
|
return res;
|
|
}
|
|
|
|
|
|
/* Next four are needed by i2c-isa */
|
|
EXPORT_SYMBOL_GPL(i2c_adapter_dev_release);
|
|
EXPORT_SYMBOL_GPL(i2c_adapter_driver);
|
|
EXPORT_SYMBOL_GPL(i2c_adapter_class);
|
|
EXPORT_SYMBOL_GPL(i2c_bus_type);
|
|
|
|
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_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");
|