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// SPDX-License-Identifier: GPL-2.0-or-later/*    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> */ /* 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> */ #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt #include <linux/cdev.h>#include <linux/compat.h>#include <linux/device.h>#include <linux/fs.h>#include <linux/i2c-dev.h>#include <linux/i2c.h>#include <linux/init.h>#include <linux/jiffies.h>#include <linux/kernel.h>#include <linux/list.h>#include <linux/module.h>#include <linux/notifier.h>#include <linux/slab.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;	struct cdev cdev;}; #define I2C_MINORS	(MINORMASK + 1)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) {		pr_err("Out of device minors (%d)\n", adap->nr);		return ERR_PTR(-ENODEV);	} 	i2c_dev = kzalloc_obj(*i2c_dev);	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 put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev){	spin_lock(&i2c_dev_list_lock);	list_del(&i2c_dev->list);	spin_unlock(&i2c_dev_list_lock);	if (del_cdev)		cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev);	put_device(&i2c_dev->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 sysfs_emit(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; 	/* Adapter must support I2C transfers */	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))		return -EOPNOTSUPP; 	if (count > 8192)		count = 8192; 	tmp = kzalloc(count, GFP_KERNEL);	if (tmp == NULL)		return -ENOMEM; 	pr_debug("i2c-%d reading %zu bytes.\n", iminor(file_inode(file)), count); 	ret = i2c_master_recv(client, tmp, count);	if (ret >= 0)		if (copy_to_user(buf, tmp, ret))			ret = -EFAULT;	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; 	/* Adapter must support I2C transfers */	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))		return -EOPNOTSUPP; 	if (count > 8192)		count = 8192; 	tmp = memdup_user(buf, count);	if (IS_ERR(tmp))		return PTR_ERR(tmp); 	pr_debug("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_rdwr(struct i2c_client *client,		unsigned nmsgs, struct i2c_msg *msgs){	u8 __user **data_ptrs;	int i, res; 	/* Adapter must support I2C transfers */	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))		return -EOPNOTSUPP; 	data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);	if (!data_ptrs)		return -ENOMEM; 	res = 0;	for (i = 0; i < nmsgs; i++) {		/* Limit the size of the message to a sane amount */		if (msgs[i].len > 8192) {			res = -EINVAL;			break;		} 		data_ptrs[i] = (u8 __user *)msgs[i].buf;		msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);		if (IS_ERR(msgs[i].buf)) {			res = PTR_ERR(msgs[i].buf);			break;		}		/* memdup_user allocates with GFP_KERNEL, so DMA is ok */		msgs[i].flags |= I2C_M_DMA_SAFE; 		/*		 * 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 (msgs[i].flags & I2C_M_RECV_LEN) {			if (!(msgs[i].flags & I2C_M_RD) ||			    msgs[i].len < 1 || msgs[i].buf[0] < 1 ||			    msgs[i].len < msgs[i].buf[0] +					     I2C_SMBUS_BLOCK_MAX) {				i++;				res = -EINVAL;				break;			} 			msgs[i].len = msgs[i].buf[0];		}	}	if (res < 0) {		int j;		for (j = 0; j < i; ++j)			kfree(msgs[j].buf);		kfree(data_ptrs);		return res;	} 	res = i2c_transfer(client->adapter, msgs, nmsgs);	while (i-- > 0) {		if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {			if (copy_to_user(data_ptrs[i], msgs[i].buf,					 msgs[i].len))				res = -EFAULT;		}		kfree(msgs[i].buf);	}	kfree(data_ptrs);	return res;} static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,		u8 read_write, u8 command, u32 size,		union i2c_smbus_data __user *data){	union i2c_smbus_data temp = {};	int datasize, res; 	if ((size != I2C_SMBUS_BYTE) &&	    (size != I2C_SMBUS_QUICK) &&	    (size != I2C_SMBUS_BYTE_DATA) &&	    (size != I2C_SMBUS_WORD_DATA) &&	    (size != I2C_SMBUS_PROC_CALL) &&	    (size != I2C_SMBUS_BLOCK_DATA) &&	    (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&	    (size != I2C_SMBUS_I2C_BLOCK_DATA) &&	    (size != I2C_SMBUS_BLOCK_PROC_CALL)) {		dev_dbg(&client->adapter->dev,			"size out of range (%x) in ioctl I2C_SMBUS.\n",			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 ((read_write != I2C_SMBUS_READ) &&	    (read_write != I2C_SMBUS_WRITE)) {		dev_dbg(&client->adapter->dev,			"read_write out of range (%x) in ioctl I2C_SMBUS.\n",			read_write);		return -EINVAL;	} 	/* Note that command values are always valid! */ 	if ((size == I2C_SMBUS_QUICK) ||	    ((size == I2C_SMBUS_BYTE) &&	    (read_write == I2C_SMBUS_WRITE)))		/* These are special: we do not use data */		return i2c_smbus_xfer(client->adapter, client->addr,				      client->flags, read_write,				      command, size, NULL); 	if (data == NULL) {		dev_dbg(&client->adapter->dev,			"data is NULL pointer in ioctl I2C_SMBUS.\n");		return -EINVAL;	} 	if ((size == I2C_SMBUS_BYTE_DATA) ||	    (size == I2C_SMBUS_BYTE))		datasize = sizeof(data->byte);	else if ((size == I2C_SMBUS_WORD_DATA) ||		 (size == I2C_SMBUS_PROC_CALL))		datasize = sizeof(data->word);	else /* size == smbus block, i2c block, or block proc. call */		datasize = sizeof(data->block); 	if ((size == I2C_SMBUS_PROC_CALL) ||	    (size == I2C_SMBUS_BLOCK_PROC_CALL) ||	    (size == I2C_SMBUS_I2C_BLOCK_DATA) ||	    (read_write == I2C_SMBUS_WRITE)) {		if (copy_from_user(&temp, data, datasize))			return -EFAULT;	}	if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {		/* Convert old I2C block commands to the new		   convention. This preserves binary compatibility. */		size = I2C_SMBUS_I2C_BLOCK_DATA;		if (read_write == I2C_SMBUS_READ)			temp.block[0] = I2C_SMBUS_BLOCK_MAX;	}	res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,	      read_write, command, size, &temp);	if (!res && ((size == I2C_SMBUS_PROC_CALL) ||		     (size == I2C_SMBUS_BLOCK_PROC_CALL) ||		     (read_write == I2C_SMBUS_READ))) {		if (copy_to_user(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:		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:		/*		 * 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)			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: {		struct i2c_rdwr_ioctl_data rdwr_arg;		struct i2c_msg *rdwr_pa;		int res; 		if (copy_from_user(&rdwr_arg,				   (struct i2c_rdwr_ioctl_data __user *)arg,				   sizeof(rdwr_arg)))			return -EFAULT; 		if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)			return -EINVAL; 		/*		 * Put an arbitrary limit on the number of messages that can		 * be sent at once		 */		if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)			return -EINVAL; 		rdwr_pa = memdup_array_user(rdwr_arg.msgs,					    rdwr_arg.nmsgs, sizeof(struct i2c_msg));		if (IS_ERR(rdwr_pa))			return PTR_ERR(rdwr_pa); 		res = i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);		kfree(rdwr_pa);		return res;	} 	case I2C_SMBUS: {		struct i2c_smbus_ioctl_data data_arg;		if (copy_from_user(&data_arg,				   (struct i2c_smbus_ioctl_data __user *) arg,				   sizeof(struct i2c_smbus_ioctl_data)))			return -EFAULT;		return i2cdev_ioctl_smbus(client, data_arg.read_write,					  data_arg.command,					  data_arg.size,					  data_arg.data);	}	case I2C_RETRIES:		if (arg > INT_MAX)			return -EINVAL; 		client->adapter->retries = arg;		break;	case I2C_TIMEOUT:		/*		 * For historical reasons, user-space sets the timeout value in		 * units of 10 ms.		 */		if (arg > INT_MAX / 10)			return -EINVAL; 		client->adapter->timeout = msecs_to_jiffies(arg * 10);		break;	default:		/* NOTE:  returning a fault code here could cause trouble

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