diff options
Diffstat (limited to 'kernel/drivers/i2c/i2c-dev.c')
| -rw-r--r-- | kernel/drivers/i2c/i2c-dev.c | 670 |
1 files changed, 670 insertions, 0 deletions
diff --git a/kernel/drivers/i2c/i2c-dev.c b/kernel/drivers/i2c/i2c-dev.c new file mode 100644 index 000000000..71c7a3975 --- /dev/null +++ b/kernel/drivers/i2c/i2c-dev.c @@ -0,0 +1,670 @@ +/* + i2c-dev.c - i2c-bus driver, char device interface + + Copyright (C) 1995-97 Simon G. Vogl + Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl> + Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. +*/ + +/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module. + But I have used so much of his original code and ideas that it seems + only fair to recognize him as co-author -- Frodo */ + +/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/notifier.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/i2c.h> +#include <linux/i2c-dev.h> +#include <linux/jiffies.h> +#include <linux/uaccess.h> + +/* + * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a + * slave (i2c_client) with which messages will be exchanged. It's coupled + * with a character special file which is accessed by user mode drivers. + * + * The list of i2c_dev structures is parallel to the i2c_adapter lists + * maintained by the driver model, and is updated using bus notifications. + */ +struct i2c_dev { + struct list_head list; + struct i2c_adapter *adap; + struct device *dev; +}; + +#define I2C_MINORS 256 +static LIST_HEAD(i2c_dev_list); +static DEFINE_SPINLOCK(i2c_dev_list_lock); + +static struct i2c_dev *i2c_dev_get_by_minor(unsigned index) +{ + struct i2c_dev *i2c_dev; + + spin_lock(&i2c_dev_list_lock); + list_for_each_entry(i2c_dev, &i2c_dev_list, list) { + if (i2c_dev->adap->nr == index) + goto found; + } + i2c_dev = NULL; +found: + spin_unlock(&i2c_dev_list_lock); + return i2c_dev; +} + +static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap) +{ + struct i2c_dev *i2c_dev; + + if (adap->nr >= I2C_MINORS) { + printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n", + adap->nr); + return ERR_PTR(-ENODEV); + } + + i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL); + if (!i2c_dev) + return ERR_PTR(-ENOMEM); + i2c_dev->adap = adap; + + spin_lock(&i2c_dev_list_lock); + list_add_tail(&i2c_dev->list, &i2c_dev_list); + spin_unlock(&i2c_dev_list_lock); + return i2c_dev; +} + +static void return_i2c_dev(struct i2c_dev *i2c_dev) +{ + spin_lock(&i2c_dev_list_lock); + list_del(&i2c_dev->list); + spin_unlock(&i2c_dev_list_lock); + kfree(i2c_dev); +} + +static ssize_t name_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt)); + + if (!i2c_dev) + return -ENODEV; + return sprintf(buf, "%s\n", i2c_dev->adap->name); +} +static DEVICE_ATTR_RO(name); + +static struct attribute *i2c_attrs[] = { + &dev_attr_name.attr, + NULL, +}; +ATTRIBUTE_GROUPS(i2c); + +/* ------------------------------------------------------------------------- */ + +/* + * After opening an instance of this character special file, a file + * descriptor starts out associated only with an i2c_adapter (and bus). + * + * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg + * traffic to any devices on the bus used by that adapter. That's because + * the i2c_msg vectors embed all the addressing information they need, and + * are submitted directly to an i2c_adapter. However, SMBus-only adapters + * don't support that interface. + * + * To use read()/write() system calls on that file descriptor, or to use + * SMBus interfaces (and work with SMBus-only hosts!), you must first issue + * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous + * (never registered) i2c_client so it holds the addressing information + * needed by those system calls and by this SMBus interface. + */ + +static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count, + loff_t *offset) +{ + char *tmp; + int ret; + + struct i2c_client *client = file->private_data; + + if (count > 8192) + count = 8192; + + tmp = kmalloc(count, GFP_KERNEL); + if (tmp == NULL) + return -ENOMEM; + + pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n", + iminor(file_inode(file)), count); + + ret = i2c_master_recv(client, tmp, count); + if (ret >= 0) + ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret; + kfree(tmp); + return ret; +} + +static ssize_t i2cdev_write(struct file *file, const char __user *buf, + size_t count, loff_t *offset) +{ + int ret; + char *tmp; + struct i2c_client *client = file->private_data; + + if (count > 8192) + count = 8192; + + tmp = memdup_user(buf, count); + if (IS_ERR(tmp)) + return PTR_ERR(tmp); + + pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n", + iminor(file_inode(file)), count); + + ret = i2c_master_send(client, tmp, count); + kfree(tmp); + return ret; +} + +static int i2cdev_check(struct device *dev, void *addrp) +{ + struct i2c_client *client = i2c_verify_client(dev); + + if (!client || client->addr != *(unsigned int *)addrp) + return 0; + + return dev->driver ? -EBUSY : 0; +} + +/* walk up mux tree */ +static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr) +{ + struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); + int result; + + result = device_for_each_child(&adapter->dev, &addr, i2cdev_check); + if (!result && parent) + result = i2cdev_check_mux_parents(parent, addr); + + return result; +} + +/* recurse down mux tree */ +static int i2cdev_check_mux_children(struct device *dev, void *addrp) +{ + int result; + + if (dev->type == &i2c_adapter_type) + result = device_for_each_child(dev, addrp, + i2cdev_check_mux_children); + else + result = i2cdev_check(dev, addrp); + + return result; +} + +/* This address checking function differs from the one in i2c-core + in that it considers an address with a registered device, but no + driver bound to it, as NOT busy. */ +static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr) +{ + struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); + int result = 0; + + if (parent) + result = i2cdev_check_mux_parents(parent, addr); + + if (!result) + result = device_for_each_child(&adapter->dev, &addr, + i2cdev_check_mux_children); + + return result; +} + +static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client, + unsigned long arg) +{ + struct i2c_rdwr_ioctl_data rdwr_arg; + struct i2c_msg *rdwr_pa; + u8 __user **data_ptrs; + int i, res; + + if (copy_from_user(&rdwr_arg, + (struct i2c_rdwr_ioctl_data __user *)arg, + sizeof(rdwr_arg))) + return -EFAULT; + + /* Put an arbitrary limit on the number of messages that can + * be sent at once */ + if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS) + return -EINVAL; + + rdwr_pa = memdup_user(rdwr_arg.msgs, + rdwr_arg.nmsgs * sizeof(struct i2c_msg)); + if (IS_ERR(rdwr_pa)) + return PTR_ERR(rdwr_pa); + + data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL); + if (data_ptrs == NULL) { + kfree(rdwr_pa); + return -ENOMEM; + } + + res = 0; + for (i = 0; i < rdwr_arg.nmsgs; i++) { + /* Limit the size of the message to a sane amount */ + if (rdwr_pa[i].len > 8192) { + res = -EINVAL; + break; + } + + data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf; + rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len); + if (IS_ERR(rdwr_pa[i].buf)) { + res = PTR_ERR(rdwr_pa[i].buf); + break; + } + + /* + * If the message length is received from the slave (similar + * to SMBus block read), we must ensure that the buffer will + * be large enough to cope with a message length of + * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus + * drivers allow. The first byte in the buffer must be + * pre-filled with the number of extra bytes, which must be + * at least one to hold the message length, but can be + * greater (for example to account for a checksum byte at + * the end of the message.) + */ + if (rdwr_pa[i].flags & I2C_M_RECV_LEN) { + if (!(rdwr_pa[i].flags & I2C_M_RD) || + rdwr_pa[i].buf[0] < 1 || + rdwr_pa[i].len < rdwr_pa[i].buf[0] + + I2C_SMBUS_BLOCK_MAX) { + res = -EINVAL; + break; + } + + rdwr_pa[i].len = rdwr_pa[i].buf[0]; + } + } + if (res < 0) { + int j; + for (j = 0; j < i; ++j) + kfree(rdwr_pa[j].buf); + kfree(data_ptrs); + kfree(rdwr_pa); + return res; + } + + res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs); + while (i-- > 0) { + if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) { + if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf, + rdwr_pa[i].len)) + res = -EFAULT; + } + kfree(rdwr_pa[i].buf); + } + kfree(data_ptrs); + kfree(rdwr_pa); + return res; +} + +static noinline int i2cdev_ioctl_smbus(struct i2c_client *client, + unsigned long arg) +{ + struct i2c_smbus_ioctl_data data_arg; + union i2c_smbus_data temp; + int datasize, res; + + if (copy_from_user(&data_arg, + (struct i2c_smbus_ioctl_data __user *) arg, + sizeof(struct i2c_smbus_ioctl_data))) + return -EFAULT; + if ((data_arg.size != I2C_SMBUS_BYTE) && + (data_arg.size != I2C_SMBUS_QUICK) && + (data_arg.size != I2C_SMBUS_BYTE_DATA) && + (data_arg.size != I2C_SMBUS_WORD_DATA) && + (data_arg.size != I2C_SMBUS_PROC_CALL) && + (data_arg.size != I2C_SMBUS_BLOCK_DATA) && + (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) && + (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) && + (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) { + dev_dbg(&client->adapter->dev, + "size out of range (%x) in ioctl I2C_SMBUS.\n", + data_arg.size); + return -EINVAL; + } + /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, + so the check is valid if size==I2C_SMBUS_QUICK too. */ + if ((data_arg.read_write != I2C_SMBUS_READ) && + (data_arg.read_write != I2C_SMBUS_WRITE)) { + dev_dbg(&client->adapter->dev, + "read_write out of range (%x) in ioctl I2C_SMBUS.\n", + data_arg.read_write); + return -EINVAL; + } + + /* Note that command values are always valid! */ + + if ((data_arg.size == I2C_SMBUS_QUICK) || + ((data_arg.size == I2C_SMBUS_BYTE) && + (data_arg.read_write == I2C_SMBUS_WRITE))) + /* These are special: we do not use data */ + return i2c_smbus_xfer(client->adapter, client->addr, + client->flags, data_arg.read_write, + data_arg.command, data_arg.size, NULL); + + if (data_arg.data == NULL) { + dev_dbg(&client->adapter->dev, + "data is NULL pointer in ioctl I2C_SMBUS.\n"); + return -EINVAL; + } + + if ((data_arg.size == I2C_SMBUS_BYTE_DATA) || + (data_arg.size == I2C_SMBUS_BYTE)) + datasize = sizeof(data_arg.data->byte); + else if ((data_arg.size == I2C_SMBUS_WORD_DATA) || + (data_arg.size == I2C_SMBUS_PROC_CALL)) + datasize = sizeof(data_arg.data->word); + else /* size == smbus block, i2c block, or block proc. call */ + datasize = sizeof(data_arg.data->block); + + if ((data_arg.size == I2C_SMBUS_PROC_CALL) || + (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || + (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) || + (data_arg.read_write == I2C_SMBUS_WRITE)) { + if (copy_from_user(&temp, data_arg.data, datasize)) + return -EFAULT; + } + if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) { + /* Convert old I2C block commands to the new + convention. This preserves binary compatibility. */ + data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA; + if (data_arg.read_write == I2C_SMBUS_READ) + temp.block[0] = I2C_SMBUS_BLOCK_MAX; + } + res = i2c_smbus_xfer(client->adapter, client->addr, client->flags, + data_arg.read_write, data_arg.command, data_arg.size, &temp); + if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) || + (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || + (data_arg.read_write == I2C_SMBUS_READ))) { + if (copy_to_user(data_arg.data, &temp, datasize)) + return -EFAULT; + } + return res; +} + +static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct i2c_client *client = file->private_data; + unsigned long funcs; + + dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", + cmd, arg); + + switch (cmd) { + case I2C_SLAVE: + case I2C_SLAVE_FORCE: + /* NOTE: devices set up to work with "new style" drivers + * can't use I2C_SLAVE, even when the device node is not + * bound to a driver. Only I2C_SLAVE_FORCE will work. + * + * Setting the PEC flag here won't affect kernel drivers, + * which will be using the i2c_client node registered with + * the driver model core. Likewise, when that client has + * the PEC flag already set, the i2c-dev driver won't see + * (or use) this setting. + */ + if ((arg > 0x3ff) || + (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) + return -EINVAL; + if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg)) + return -EBUSY; + /* REVISIT: address could become busy later */ + client->addr = arg; + return 0; + case I2C_TENBIT: + if (arg) + client->flags |= I2C_M_TEN; + else + client->flags &= ~I2C_M_TEN; + return 0; + case I2C_PEC: + if (arg) + client->flags |= I2C_CLIENT_PEC; + else + client->flags &= ~I2C_CLIENT_PEC; + return 0; + case I2C_FUNCS: + funcs = i2c_get_functionality(client->adapter); + return put_user(funcs, (unsigned long __user *)arg); + + case I2C_RDWR: + return i2cdev_ioctl_rdrw(client, arg); + + case I2C_SMBUS: + return i2cdev_ioctl_smbus(client, arg); + + 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); |