xref: /openbmc/linux/drivers/i2c/i2c-dev.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2     i2c-dev.c - i2c-bus driver, char device interface
3 
4     Copyright (C) 1995-97 Simon G. Vogl
5     Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
6     Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7 
8     This program is free software; you can redistribute it and/or modify
9     it under the terms of the GNU General Public License as published by
10     the Free Software Foundation; either version 2 of the License, or
11     (at your option) any later version.
12 
13     This program is distributed in the hope that it will be useful,
14     but WITHOUT ANY WARRANTY; without even the implied warranty of
15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16     GNU General Public License for more details.
17 
18     You should have received a copy of the GNU General Public License
19     along with this program; if not, write to the Free Software
20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22 
23 /* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
24    But I have used so much of his original code and ideas that it seems
25    only fair to recognize him as co-author -- Frodo */
26 
27 /* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
28 
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/fs.h>
32 #include <linux/slab.h>
33 #include <linux/init.h>
34 #include <linux/list.h>
35 #include <linux/i2c.h>
36 #include <linux/i2c-dev.h>
37 #include <asm/uaccess.h>
38 
39 static struct i2c_driver i2cdev_driver;
40 
41 struct i2c_dev {
42 	struct list_head list;
43 	struct i2c_adapter *adap;
44 	struct device *dev;
45 };
46 
47 #define I2C_MINORS	256
48 static LIST_HEAD(i2c_dev_list);
49 static DEFINE_SPINLOCK(i2c_dev_list_lock);
50 
51 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
52 {
53 	struct i2c_dev *i2c_dev;
54 
55 	spin_lock(&i2c_dev_list_lock);
56 	list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
57 		if (i2c_dev->adap->nr == index)
58 			goto found;
59 	}
60 	i2c_dev = NULL;
61 found:
62 	spin_unlock(&i2c_dev_list_lock);
63 	return i2c_dev;
64 }
65 
66 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
67 {
68 	struct i2c_dev *i2c_dev;
69 
70 	if (adap->nr >= I2C_MINORS) {
71 		printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
72 		       adap->nr);
73 		return ERR_PTR(-ENODEV);
74 	}
75 
76 	i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
77 	if (!i2c_dev)
78 		return ERR_PTR(-ENOMEM);
79 	i2c_dev->adap = adap;
80 
81 	spin_lock(&i2c_dev_list_lock);
82 	list_add_tail(&i2c_dev->list, &i2c_dev_list);
83 	spin_unlock(&i2c_dev_list_lock);
84 	return i2c_dev;
85 }
86 
87 static void return_i2c_dev(struct i2c_dev *i2c_dev)
88 {
89 	spin_lock(&i2c_dev_list_lock);
90 	list_del(&i2c_dev->list);
91 	spin_unlock(&i2c_dev_list_lock);
92 	kfree(i2c_dev);
93 }
94 
95 static ssize_t show_adapter_name(struct device *dev,
96 				 struct device_attribute *attr, char *buf)
97 {
98 	struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
99 
100 	if (!i2c_dev)
101 		return -ENODEV;
102 	return sprintf(buf, "%s\n", i2c_dev->adap->name);
103 }
104 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
105 
106 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
107                             loff_t *offset)
108 {
109 	char *tmp;
110 	int ret;
111 
112 	struct i2c_client *client = (struct i2c_client *)file->private_data;
113 
114 	if (count > 8192)
115 		count = 8192;
116 
117 	tmp = kmalloc(count,GFP_KERNEL);
118 	if (tmp==NULL)
119 		return -ENOMEM;
120 
121 	pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
122 		iminor(file->f_path.dentry->d_inode), count);
123 
124 	ret = i2c_master_recv(client,tmp,count);
125 	if (ret >= 0)
126 		ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
127 	kfree(tmp);
128 	return ret;
129 }
130 
131 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
132                              loff_t *offset)
133 {
134 	int ret;
135 	char *tmp;
136 	struct i2c_client *client = (struct i2c_client *)file->private_data;
137 
138 	if (count > 8192)
139 		count = 8192;
140 
141 	tmp = kmalloc(count,GFP_KERNEL);
142 	if (tmp==NULL)
143 		return -ENOMEM;
144 	if (copy_from_user(tmp,buf,count)) {
145 		kfree(tmp);
146 		return -EFAULT;
147 	}
148 
149 	pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
150 		iminor(file->f_path.dentry->d_inode), count);
151 
152 	ret = i2c_master_send(client,tmp,count);
153 	kfree(tmp);
154 	return ret;
155 }
156 
157 static int i2cdev_ioctl(struct inode *inode, struct file *file,
158 		unsigned int cmd, unsigned long arg)
159 {
160 	struct i2c_client *client = (struct i2c_client *)file->private_data;
161 	struct i2c_rdwr_ioctl_data rdwr_arg;
162 	struct i2c_smbus_ioctl_data data_arg;
163 	union i2c_smbus_data temp;
164 	struct i2c_msg *rdwr_pa;
165 	u8 __user **data_ptrs;
166 	int i,datasize,res;
167 	unsigned long funcs;
168 
169 	dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
170 		cmd, arg);
171 
172 	switch ( cmd ) {
173 	case I2C_SLAVE:
174 	case I2C_SLAVE_FORCE:
175 		if ((arg > 0x3ff) ||
176 		    (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
177 			return -EINVAL;
178 		if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
179 			return -EBUSY;
180 		client->addr = arg;
181 		return 0;
182 	case I2C_TENBIT:
183 		if (arg)
184 			client->flags |= I2C_M_TEN;
185 		else
186 			client->flags &= ~I2C_M_TEN;
187 		return 0;
188 	case I2C_PEC:
189 		if (arg)
190 			client->flags |= I2C_CLIENT_PEC;
191 		else
192 			client->flags &= ~I2C_CLIENT_PEC;
193 		return 0;
194 	case I2C_FUNCS:
195 		funcs = i2c_get_functionality(client->adapter);
196 		return put_user(funcs, (unsigned long __user *)arg);
197 
198 	case I2C_RDWR:
199 		if (copy_from_user(&rdwr_arg,
200 				   (struct i2c_rdwr_ioctl_data __user *)arg,
201 				   sizeof(rdwr_arg)))
202 			return -EFAULT;
203 
204 		/* Put an arbitrary limit on the number of messages that can
205 		 * be sent at once */
206 		if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
207 			return -EINVAL;
208 
209 		rdwr_pa = (struct i2c_msg *)
210 			kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
211 			GFP_KERNEL);
212 
213 		if (rdwr_pa == NULL) return -ENOMEM;
214 
215 		if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
216 				   rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
217 			kfree(rdwr_pa);
218 			return -EFAULT;
219 		}
220 
221 		data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
222 		if (data_ptrs == NULL) {
223 			kfree(rdwr_pa);
224 			return -ENOMEM;
225 		}
226 
227 		res = 0;
228 		for( i=0; i<rdwr_arg.nmsgs; i++ ) {
229 			/* Limit the size of the message to a sane amount */
230 			if (rdwr_pa[i].len > 8192) {
231 				res = -EINVAL;
232 				break;
233 			}
234 			data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
235 			rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
236 			if(rdwr_pa[i].buf == NULL) {
237 				res = -ENOMEM;
238 				break;
239 			}
240 			if(copy_from_user(rdwr_pa[i].buf,
241 				data_ptrs[i],
242 				rdwr_pa[i].len)) {
243 					++i; /* Needs to be kfreed too */
244 					res = -EFAULT;
245 				break;
246 			}
247 		}
248 		if (res < 0) {
249 			int j;
250 			for (j = 0; j < i; ++j)
251 				kfree(rdwr_pa[j].buf);
252 			kfree(data_ptrs);
253 			kfree(rdwr_pa);
254 			return res;
255 		}
256 
257 		res = i2c_transfer(client->adapter,
258 			rdwr_pa,
259 			rdwr_arg.nmsgs);
260 		while(i-- > 0) {
261 			if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
262 				if(copy_to_user(
263 					data_ptrs[i],
264 					rdwr_pa[i].buf,
265 					rdwr_pa[i].len)) {
266 					res = -EFAULT;
267 				}
268 			}
269 			kfree(rdwr_pa[i].buf);
270 		}
271 		kfree(data_ptrs);
272 		kfree(rdwr_pa);
273 		return res;
274 
275 	case I2C_SMBUS:
276 		if (copy_from_user(&data_arg,
277 		                   (struct i2c_smbus_ioctl_data __user *) arg,
278 		                   sizeof(struct i2c_smbus_ioctl_data)))
279 			return -EFAULT;
280 		if ((data_arg.size != I2C_SMBUS_BYTE) &&
281 		    (data_arg.size != I2C_SMBUS_QUICK) &&
282 		    (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
283 		    (data_arg.size != I2C_SMBUS_WORD_DATA) &&
284 		    (data_arg.size != I2C_SMBUS_PROC_CALL) &&
285 		    (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
286 		    (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
287 		    (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
288 			dev_dbg(&client->adapter->dev,
289 				"size out of range (%x) in ioctl I2C_SMBUS.\n",
290 				data_arg.size);
291 			return -EINVAL;
292 		}
293 		/* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
294 		   so the check is valid if size==I2C_SMBUS_QUICK too. */
295 		if ((data_arg.read_write != I2C_SMBUS_READ) &&
296 		    (data_arg.read_write != I2C_SMBUS_WRITE)) {
297 			dev_dbg(&client->adapter->dev,
298 				"read_write out of range (%x) in ioctl I2C_SMBUS.\n",
299 				data_arg.read_write);
300 			return -EINVAL;
301 		}
302 
303 		/* Note that command values are always valid! */
304 
305 		if ((data_arg.size == I2C_SMBUS_QUICK) ||
306 		    ((data_arg.size == I2C_SMBUS_BYTE) &&
307 		    (data_arg.read_write == I2C_SMBUS_WRITE)))
308 			/* These are special: we do not use data */
309 			return i2c_smbus_xfer(client->adapter, client->addr,
310 					      client->flags,
311 					      data_arg.read_write,
312 					      data_arg.command,
313 					      data_arg.size, NULL);
314 
315 		if (data_arg.data == NULL) {
316 			dev_dbg(&client->adapter->dev,
317 				"data is NULL pointer in ioctl I2C_SMBUS.\n");
318 			return -EINVAL;
319 		}
320 
321 		if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
322 		    (data_arg.size == I2C_SMBUS_BYTE))
323 			datasize = sizeof(data_arg.data->byte);
324 		else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
325 		         (data_arg.size == I2C_SMBUS_PROC_CALL))
326 			datasize = sizeof(data_arg.data->word);
327 		else /* size == smbus block, i2c block, or block proc. call */
328 			datasize = sizeof(data_arg.data->block);
329 
330 		if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
331 		    (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
332 		    (data_arg.read_write == I2C_SMBUS_WRITE)) {
333 			if (copy_from_user(&temp, data_arg.data, datasize))
334 				return -EFAULT;
335 		}
336 		res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
337 		      data_arg.read_write,
338 		      data_arg.command,data_arg.size,&temp);
339 		if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
340 		              (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
341 			      (data_arg.read_write == I2C_SMBUS_READ))) {
342 			if (copy_to_user(data_arg.data, &temp, datasize))
343 				return -EFAULT;
344 		}
345 		return res;
346 
347 	default:
348 		return i2c_control(client,cmd,arg);
349 	}
350 	return 0;
351 }
352 
353 static int i2cdev_open(struct inode *inode, struct file *file)
354 {
355 	unsigned int minor = iminor(inode);
356 	struct i2c_client *client;
357 	struct i2c_adapter *adap;
358 	struct i2c_dev *i2c_dev;
359 
360 	i2c_dev = i2c_dev_get_by_minor(minor);
361 	if (!i2c_dev)
362 		return -ENODEV;
363 
364 	adap = i2c_get_adapter(i2c_dev->adap->nr);
365 	if (!adap)
366 		return -ENODEV;
367 
368 	client = kzalloc(sizeof(*client), GFP_KERNEL);
369 	if (!client) {
370 		i2c_put_adapter(adap);
371 		return -ENOMEM;
372 	}
373 	snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
374 	client->driver = &i2cdev_driver;
375 
376 	/* registered with adapter, passed as client to user */
377 	client->adapter = adap;
378 	file->private_data = client;
379 
380 	return 0;
381 }
382 
383 static int i2cdev_release(struct inode *inode, struct file *file)
384 {
385 	struct i2c_client *client = file->private_data;
386 
387 	i2c_put_adapter(client->adapter);
388 	kfree(client);
389 	file->private_data = NULL;
390 
391 	return 0;
392 }
393 
394 static const struct file_operations i2cdev_fops = {
395 	.owner		= THIS_MODULE,
396 	.llseek		= no_llseek,
397 	.read		= i2cdev_read,
398 	.write		= i2cdev_write,
399 	.ioctl		= i2cdev_ioctl,
400 	.open		= i2cdev_open,
401 	.release	= i2cdev_release,
402 };
403 
404 static struct class *i2c_dev_class;
405 
406 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
407 {
408 	struct i2c_dev *i2c_dev;
409 	int res;
410 
411 	i2c_dev = get_free_i2c_dev(adap);
412 	if (IS_ERR(i2c_dev))
413 		return PTR_ERR(i2c_dev);
414 
415 	/* register this i2c device with the driver core */
416 	i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
417 				     MKDEV(I2C_MAJOR, adap->nr),
418 				     "i2c-%d", adap->nr);
419 	if (IS_ERR(i2c_dev->dev)) {
420 		res = PTR_ERR(i2c_dev->dev);
421 		goto error;
422 	}
423 	res = device_create_file(i2c_dev->dev, &dev_attr_name);
424 	if (res)
425 		goto error_destroy;
426 
427 	pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
428 		 adap->name, adap->nr);
429 	return 0;
430 error_destroy:
431 	device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
432 error:
433 	return_i2c_dev(i2c_dev);
434 	return res;
435 }
436 
437 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
438 {
439 	struct i2c_dev *i2c_dev;
440 
441 	i2c_dev = i2c_dev_get_by_minor(adap->nr);
442 	if (!i2c_dev) /* attach_adapter must have failed */
443 		return 0;
444 
445 	device_remove_file(i2c_dev->dev, &dev_attr_name);
446 	return_i2c_dev(i2c_dev);
447 	device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
448 
449 	pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
450 	return 0;
451 }
452 
453 static int i2cdev_detach_client(struct i2c_client *client)
454 {
455 	return 0;
456 }
457 
458 static struct i2c_driver i2cdev_driver = {
459 	.driver = {
460 		.name	= "dev_driver",
461 	},
462 	.id		= I2C_DRIVERID_I2CDEV,
463 	.attach_adapter	= i2cdev_attach_adapter,
464 	.detach_adapter	= i2cdev_detach_adapter,
465 	.detach_client	= i2cdev_detach_client,
466 };
467 
468 static int __init i2c_dev_init(void)
469 {
470 	int res;
471 
472 	printk(KERN_INFO "i2c /dev entries driver\n");
473 
474 	res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
475 	if (res)
476 		goto out;
477 
478 	i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
479 	if (IS_ERR(i2c_dev_class))
480 		goto out_unreg_chrdev;
481 
482 	res = i2c_add_driver(&i2cdev_driver);
483 	if (res)
484 		goto out_unreg_class;
485 
486 	return 0;
487 
488 out_unreg_class:
489 	class_destroy(i2c_dev_class);
490 out_unreg_chrdev:
491 	unregister_chrdev(I2C_MAJOR, "i2c");
492 out:
493 	printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
494 	return res;
495 }
496 
497 static void __exit i2c_dev_exit(void)
498 {
499 	i2c_del_driver(&i2cdev_driver);
500 	class_destroy(i2c_dev_class);
501 	unregister_chrdev(I2C_MAJOR,"i2c");
502 }
503 
504 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
505 		"Simon G. Vogl <simon@tk.uni-linz.ac.at>");
506 MODULE_DESCRIPTION("I2C /dev entries driver");
507 MODULE_LICENSE("GPL");
508 
509 module_init(i2c_dev_init);
510 module_exit(i2c_dev_exit);
511