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9e685c84c2
The first part of the comment is wrong since November 2007, delete it. The second part of the comment is related to I2C_PEC, not I2C_SLAVE, so move it where it belongs. Signed-off-by: Jean Delvare <jdelvare@suse.de> Cc: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
668 lines
18 KiB
C
668 lines
18 KiB
C
/*
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i2c-dev.c - i2c-bus driver, char device interface
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Copyright (C) 1995-97 Simon G. Vogl
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Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
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Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
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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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*/
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/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
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But I have used so much of his original code and ideas that it seems
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only fair to recognize him as co-author -- Frodo */
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/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/notifier.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/i2c.h>
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#include <linux/i2c-dev.h>
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#include <linux/jiffies.h>
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#include <linux/uaccess.h>
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/*
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* An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
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* slave (i2c_client) with which messages will be exchanged. It's coupled
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* with a character special file which is accessed by user mode drivers.
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*
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* The list of i2c_dev structures is parallel to the i2c_adapter lists
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* maintained by the driver model, and is updated using bus notifications.
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*/
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struct i2c_dev {
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struct list_head list;
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struct i2c_adapter *adap;
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struct device *dev;
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};
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#define I2C_MINORS 256
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static LIST_HEAD(i2c_dev_list);
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static DEFINE_SPINLOCK(i2c_dev_list_lock);
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static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
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{
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struct i2c_dev *i2c_dev;
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spin_lock(&i2c_dev_list_lock);
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list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
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if (i2c_dev->adap->nr == index)
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goto found;
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}
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i2c_dev = NULL;
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found:
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spin_unlock(&i2c_dev_list_lock);
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return i2c_dev;
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}
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static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
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{
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struct i2c_dev *i2c_dev;
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if (adap->nr >= I2C_MINORS) {
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printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
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adap->nr);
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return ERR_PTR(-ENODEV);
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}
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i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
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if (!i2c_dev)
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return ERR_PTR(-ENOMEM);
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i2c_dev->adap = adap;
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spin_lock(&i2c_dev_list_lock);
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list_add_tail(&i2c_dev->list, &i2c_dev_list);
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spin_unlock(&i2c_dev_list_lock);
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return i2c_dev;
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}
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static void return_i2c_dev(struct i2c_dev *i2c_dev)
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{
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spin_lock(&i2c_dev_list_lock);
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list_del(&i2c_dev->list);
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spin_unlock(&i2c_dev_list_lock);
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kfree(i2c_dev);
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}
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static ssize_t name_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
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if (!i2c_dev)
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return -ENODEV;
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return sprintf(buf, "%s\n", i2c_dev->adap->name);
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}
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static DEVICE_ATTR_RO(name);
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static struct attribute *i2c_attrs[] = {
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&dev_attr_name.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(i2c);
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/* ------------------------------------------------------------------------- */
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/*
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* After opening an instance of this character special file, a file
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* descriptor starts out associated only with an i2c_adapter (and bus).
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*
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* Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
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* traffic to any devices on the bus used by that adapter. That's because
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* the i2c_msg vectors embed all the addressing information they need, and
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* are submitted directly to an i2c_adapter. However, SMBus-only adapters
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* don't support that interface.
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*
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* To use read()/write() system calls on that file descriptor, or to use
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* SMBus interfaces (and work with SMBus-only hosts!), you must first issue
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* an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
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* (never registered) i2c_client so it holds the addressing information
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* needed by those system calls and by this SMBus interface.
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*/
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static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
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loff_t *offset)
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{
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char *tmp;
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int ret;
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struct i2c_client *client = file->private_data;
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if (count > 8192)
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count = 8192;
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tmp = kmalloc(count, GFP_KERNEL);
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if (tmp == NULL)
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return -ENOMEM;
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pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
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iminor(file_inode(file)), count);
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ret = i2c_master_recv(client, tmp, count);
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if (ret >= 0)
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ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
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kfree(tmp);
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return ret;
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}
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static ssize_t i2cdev_write(struct file *file, const char __user *buf,
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size_t count, loff_t *offset)
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{
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int ret;
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char *tmp;
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struct i2c_client *client = file->private_data;
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if (count > 8192)
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count = 8192;
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tmp = memdup_user(buf, count);
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if (IS_ERR(tmp))
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return PTR_ERR(tmp);
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pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
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iminor(file_inode(file)), count);
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ret = i2c_master_send(client, tmp, count);
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kfree(tmp);
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return ret;
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}
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static int i2cdev_check(struct device *dev, void *addrp)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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if (!client || client->addr != *(unsigned int *)addrp)
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return 0;
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return dev->driver ? -EBUSY : 0;
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}
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/* walk up mux tree */
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static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
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{
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struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
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int result;
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result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
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if (!result && parent)
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result = i2cdev_check_mux_parents(parent, addr);
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return result;
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}
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/* recurse down mux tree */
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static int i2cdev_check_mux_children(struct device *dev, void *addrp)
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{
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int result;
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if (dev->type == &i2c_adapter_type)
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result = device_for_each_child(dev, addrp,
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i2cdev_check_mux_children);
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else
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result = i2cdev_check(dev, addrp);
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return result;
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}
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/* This address checking function differs from the one in i2c-core
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in that it considers an address with a registered device, but no
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driver bound to it, as NOT busy. */
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static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
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{
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struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
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int result = 0;
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if (parent)
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result = i2cdev_check_mux_parents(parent, addr);
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if (!result)
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result = device_for_each_child(&adapter->dev, &addr,
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i2cdev_check_mux_children);
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return result;
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}
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static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
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unsigned long arg)
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{
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struct i2c_rdwr_ioctl_data rdwr_arg;
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struct i2c_msg *rdwr_pa;
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u8 __user **data_ptrs;
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int i, res;
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if (copy_from_user(&rdwr_arg,
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(struct i2c_rdwr_ioctl_data __user *)arg,
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sizeof(rdwr_arg)))
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return -EFAULT;
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/* Put an arbitrary limit on the number of messages that can
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* be sent at once */
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if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
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return -EINVAL;
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rdwr_pa = memdup_user(rdwr_arg.msgs,
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rdwr_arg.nmsgs * sizeof(struct i2c_msg));
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if (IS_ERR(rdwr_pa))
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return PTR_ERR(rdwr_pa);
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data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
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if (data_ptrs == NULL) {
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kfree(rdwr_pa);
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return -ENOMEM;
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}
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res = 0;
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for (i = 0; i < rdwr_arg.nmsgs; i++) {
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/* Limit the size of the message to a sane amount */
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if (rdwr_pa[i].len > 8192) {
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res = -EINVAL;
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break;
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}
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data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
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rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
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if (IS_ERR(rdwr_pa[i].buf)) {
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res = PTR_ERR(rdwr_pa[i].buf);
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break;
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}
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/*
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* If the message length is received from the slave (similar
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* to SMBus block read), we must ensure that the buffer will
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* be large enough to cope with a message length of
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* I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
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* drivers allow. The first byte in the buffer must be
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* pre-filled with the number of extra bytes, which must be
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* at least one to hold the message length, but can be
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* greater (for example to account for a checksum byte at
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* the end of the message.)
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*/
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if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
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if (!(rdwr_pa[i].flags & I2C_M_RD) ||
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rdwr_pa[i].buf[0] < 1 ||
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rdwr_pa[i].len < rdwr_pa[i].buf[0] +
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I2C_SMBUS_BLOCK_MAX) {
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res = -EINVAL;
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break;
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}
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rdwr_pa[i].len = rdwr_pa[i].buf[0];
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}
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}
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if (res < 0) {
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int j;
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for (j = 0; j < i; ++j)
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kfree(rdwr_pa[j].buf);
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kfree(data_ptrs);
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kfree(rdwr_pa);
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return res;
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}
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res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
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while (i-- > 0) {
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if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
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if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
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rdwr_pa[i].len))
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res = -EFAULT;
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}
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kfree(rdwr_pa[i].buf);
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}
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kfree(data_ptrs);
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kfree(rdwr_pa);
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return res;
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}
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static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
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unsigned long arg)
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{
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struct i2c_smbus_ioctl_data data_arg;
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union i2c_smbus_data temp;
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int datasize, res;
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if (copy_from_user(&data_arg,
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(struct i2c_smbus_ioctl_data __user *) arg,
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sizeof(struct i2c_smbus_ioctl_data)))
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return -EFAULT;
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if ((data_arg.size != I2C_SMBUS_BYTE) &&
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(data_arg.size != I2C_SMBUS_QUICK) &&
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(data_arg.size != I2C_SMBUS_BYTE_DATA) &&
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(data_arg.size != I2C_SMBUS_WORD_DATA) &&
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(data_arg.size != I2C_SMBUS_PROC_CALL) &&
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(data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
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(data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
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(data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
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(data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
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dev_dbg(&client->adapter->dev,
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"size out of range (%x) in ioctl I2C_SMBUS.\n",
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data_arg.size);
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return -EINVAL;
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}
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/* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
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so the check is valid if size==I2C_SMBUS_QUICK too. */
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if ((data_arg.read_write != I2C_SMBUS_READ) &&
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(data_arg.read_write != I2C_SMBUS_WRITE)) {
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dev_dbg(&client->adapter->dev,
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"read_write out of range (%x) in ioctl I2C_SMBUS.\n",
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data_arg.read_write);
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return -EINVAL;
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}
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/* Note that command values are always valid! */
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if ((data_arg.size == I2C_SMBUS_QUICK) ||
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((data_arg.size == I2C_SMBUS_BYTE) &&
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(data_arg.read_write == I2C_SMBUS_WRITE)))
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/* These are special: we do not use data */
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return i2c_smbus_xfer(client->adapter, client->addr,
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client->flags, data_arg.read_write,
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data_arg.command, data_arg.size, NULL);
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if (data_arg.data == NULL) {
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dev_dbg(&client->adapter->dev,
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"data is NULL pointer in ioctl I2C_SMBUS.\n");
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return -EINVAL;
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}
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if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
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(data_arg.size == I2C_SMBUS_BYTE))
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datasize = sizeof(data_arg.data->byte);
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else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
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(data_arg.size == I2C_SMBUS_PROC_CALL))
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datasize = sizeof(data_arg.data->word);
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else /* size == smbus block, i2c block, or block proc. call */
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datasize = sizeof(data_arg.data->block);
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if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
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(data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
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(data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
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(data_arg.read_write == I2C_SMBUS_WRITE)) {
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if (copy_from_user(&temp, data_arg.data, datasize))
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return -EFAULT;
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}
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if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
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/* Convert old I2C block commands to the new
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convention. This preserves binary compatibility. */
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data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
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if (data_arg.read_write == I2C_SMBUS_READ)
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temp.block[0] = I2C_SMBUS_BLOCK_MAX;
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}
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res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
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data_arg.read_write, data_arg.command, data_arg.size, &temp);
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if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
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(data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
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(data_arg.read_write == I2C_SMBUS_READ))) {
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if (copy_to_user(data_arg.data, &temp, datasize))
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return -EFAULT;
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}
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return res;
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}
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static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct i2c_client *client = file->private_data;
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unsigned long funcs;
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dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
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cmd, arg);
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switch (cmd) {
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case I2C_SLAVE:
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case I2C_SLAVE_FORCE:
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if ((arg > 0x3ff) ||
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(((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
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return -EINVAL;
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if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
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return -EBUSY;
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/* REVISIT: address could become busy later */
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client->addr = arg;
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return 0;
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case I2C_TENBIT:
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if (arg)
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client->flags |= I2C_M_TEN;
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else
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client->flags &= ~I2C_M_TEN;
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return 0;
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case I2C_PEC:
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/*
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* Setting the PEC flag here won't affect kernel drivers,
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* which will be using the i2c_client node registered with
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* the driver model core. Likewise, when that client has
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* the PEC flag already set, the i2c-dev driver won't see
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* (or use) this setting.
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*/
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if (arg)
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client->flags |= I2C_CLIENT_PEC;
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else
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client->flags &= ~I2C_CLIENT_PEC;
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return 0;
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case I2C_FUNCS:
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funcs = i2c_get_functionality(client->adapter);
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return put_user(funcs, (unsigned long __user *)arg);
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case I2C_RDWR:
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return i2cdev_ioctl_rdwr(client, arg);
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case I2C_SMBUS:
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return i2cdev_ioctl_smbus(client, arg);
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|
|
|
case I2C_RETRIES:
|
|
client->adapter->retries = arg;
|
|
break;
|
|
case I2C_TIMEOUT:
|
|
/* For historical reasons, user-space sets the timeout
|
|
* value in units of 10 ms.
|
|
*/
|
|
client->adapter->timeout = msecs_to_jiffies(arg * 10);
|
|
break;
|
|
default:
|
|
/* NOTE: returning a fault code here could cause trouble
|
|
* in buggy userspace code. Some old kernel bugs returned
|
|
* zero in this case, and userspace code might accidentally
|
|
* have depended on that bug.
|
|
*/
|
|
return -ENOTTY;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int i2cdev_open(struct inode *inode, struct file *file)
|
|
{
|
|
unsigned int minor = iminor(inode);
|
|
struct i2c_client *client;
|
|
struct i2c_adapter *adap;
|
|
struct i2c_dev *i2c_dev;
|
|
|
|
i2c_dev = i2c_dev_get_by_minor(minor);
|
|
if (!i2c_dev)
|
|
return -ENODEV;
|
|
|
|
adap = i2c_get_adapter(i2c_dev->adap->nr);
|
|
if (!adap)
|
|
return -ENODEV;
|
|
|
|
/* This creates an anonymous i2c_client, which may later be
|
|
* pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
|
|
*
|
|
* This client is ** NEVER REGISTERED ** with the driver model
|
|
* or I2C core code!! It just holds private copies of addressing
|
|
* information and maybe a PEC flag.
|
|
*/
|
|
client = kzalloc(sizeof(*client), GFP_KERNEL);
|
|
if (!client) {
|
|
i2c_put_adapter(adap);
|
|
return -ENOMEM;
|
|
}
|
|
snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
|
|
|
|
client->adapter = adap;
|
|
file->private_data = client;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int i2cdev_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct i2c_client *client = file->private_data;
|
|
|
|
i2c_put_adapter(client->adapter);
|
|
kfree(client);
|
|
file->private_data = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations i2cdev_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.read = i2cdev_read,
|
|
.write = i2cdev_write,
|
|
.unlocked_ioctl = i2cdev_ioctl,
|
|
.open = i2cdev_open,
|
|
.release = i2cdev_release,
|
|
};
|
|
|
|
/* ------------------------------------------------------------------------- */
|
|
|
|
static struct class *i2c_dev_class;
|
|
|
|
static int i2cdev_attach_adapter(struct device *dev, void *dummy)
|
|
{
|
|
struct i2c_adapter *adap;
|
|
struct i2c_dev *i2c_dev;
|
|
int res;
|
|
|
|
if (dev->type != &i2c_adapter_type)
|
|
return 0;
|
|
adap = to_i2c_adapter(dev);
|
|
|
|
i2c_dev = get_free_i2c_dev(adap);
|
|
if (IS_ERR(i2c_dev))
|
|
return PTR_ERR(i2c_dev);
|
|
|
|
/* register this i2c device with the driver core */
|
|
i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
|
|
MKDEV(I2C_MAJOR, adap->nr), NULL,
|
|
"i2c-%d", adap->nr);
|
|
if (IS_ERR(i2c_dev->dev)) {
|
|
res = PTR_ERR(i2c_dev->dev);
|
|
goto error;
|
|
}
|
|
|
|
pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
|
|
adap->name, adap->nr);
|
|
return 0;
|
|
error:
|
|
return_i2c_dev(i2c_dev);
|
|
return res;
|
|
}
|
|
|
|
static int i2cdev_detach_adapter(struct device *dev, void *dummy)
|
|
{
|
|
struct i2c_adapter *adap;
|
|
struct i2c_dev *i2c_dev;
|
|
|
|
if (dev->type != &i2c_adapter_type)
|
|
return 0;
|
|
adap = to_i2c_adapter(dev);
|
|
|
|
i2c_dev = i2c_dev_get_by_minor(adap->nr);
|
|
if (!i2c_dev) /* attach_adapter must have failed */
|
|
return 0;
|
|
|
|
return_i2c_dev(i2c_dev);
|
|
device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
|
|
|
|
pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
|
|
return 0;
|
|
}
|
|
|
|
static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
|
|
void *data)
|
|
{
|
|
struct device *dev = data;
|
|
|
|
switch (action) {
|
|
case BUS_NOTIFY_ADD_DEVICE:
|
|
return i2cdev_attach_adapter(dev, NULL);
|
|
case BUS_NOTIFY_DEL_DEVICE:
|
|
return i2cdev_detach_adapter(dev, NULL);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct notifier_block i2cdev_notifier = {
|
|
.notifier_call = i2cdev_notifier_call,
|
|
};
|
|
|
|
/* ------------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* module load/unload record keeping
|
|
*/
|
|
|
|
static int __init i2c_dev_init(void)
|
|
{
|
|
int res;
|
|
|
|
printk(KERN_INFO "i2c /dev entries driver\n");
|
|
|
|
res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
|
|
if (res)
|
|
goto out;
|
|
|
|
i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
|
|
if (IS_ERR(i2c_dev_class)) {
|
|
res = PTR_ERR(i2c_dev_class);
|
|
goto out_unreg_chrdev;
|
|
}
|
|
i2c_dev_class->dev_groups = i2c_groups;
|
|
|
|
/* Keep track of adapters which will be added or removed later */
|
|
res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
|
|
if (res)
|
|
goto out_unreg_class;
|
|
|
|
/* Bind to already existing adapters right away */
|
|
i2c_for_each_dev(NULL, i2cdev_attach_adapter);
|
|
|
|
return 0;
|
|
|
|
out_unreg_class:
|
|
class_destroy(i2c_dev_class);
|
|
out_unreg_chrdev:
|
|
unregister_chrdev(I2C_MAJOR, "i2c");
|
|
out:
|
|
printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
|
|
return res;
|
|
}
|
|
|
|
static void __exit i2c_dev_exit(void)
|
|
{
|
|
bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
|
|
i2c_for_each_dev(NULL, i2cdev_detach_adapter);
|
|
class_destroy(i2c_dev_class);
|
|
unregister_chrdev(I2C_MAJOR, "i2c");
|
|
}
|
|
|
|
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
|
|
"Simon G. Vogl <simon@tk.uni-linz.ac.at>");
|
|
MODULE_DESCRIPTION("I2C /dev entries driver");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
module_init(i2c_dev_init);
|
|
module_exit(i2c_dev_exit);
|