1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Simple synchronous userspace interface to SPI devices
  4 *
  5 * Copyright (C) 2006 SWAPP
  6 *	Andrea Paterniani <a.paterniani@swapp-eng.it>
  7 * Copyright (C) 2007 David Brownell (simplification, cleanup)
  8 */
  9
 10#include <linux/init.h>
 11#include <linux/ioctl.h>
 12#include <linux/fs.h>
 13#include <linux/device.h>
 14#include <linux/err.h>
 15#include <linux/list.h>
 16#include <linux/errno.h>
 17#include <linux/mod_devicetable.h>
 18#include <linux/module.h>
 19#include <linux/mutex.h>
 20#include <linux/property.h>
 21#include <linux/slab.h>
 22#include <linux/compat.h>
 23
 24#include <linux/spi/spi.h>
 25#include <linux/spi/spidev.h>
 26
 27#include <linux/uaccess.h>
 28
 29
 30/*
 31 * This supports access to SPI devices using normal userspace I/O calls.
 32 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
 33 * and often mask message boundaries, full SPI support requires full duplex
 34 * transfers.  There are several kinds of internal message boundaries to
 35 * handle chipselect management and other protocol options.
 36 *
 37 * SPI has a character major number assigned.  We allocate minor numbers
 38 * dynamically using a bitmask.  You must use hotplug tools, such as udev
 39 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
 40 * nodes, since there is no fixed association of minor numbers with any
 41 * particular SPI bus or device.
 42 */
 43#define SPIDEV_MAJOR			153	/* assigned */
 44#define N_SPI_MINORS			32	/* ... up to 256 */
 45
 46static DECLARE_BITMAP(minors, N_SPI_MINORS);
 47
 48static_assert(N_SPI_MINORS > 0 && N_SPI_MINORS <= 256);
 49
 50/* Bit masks for spi_device.mode management.  Note that incorrect
 51 * settings for some settings can cause *lots* of trouble for other
 52 * devices on a shared bus:
 53 *
 54 *  - CS_HIGH ... this device will be active when it shouldn't be
 55 *  - 3WIRE ... when active, it won't behave as it should
 56 *  - NO_CS ... there will be no explicit message boundaries; this
 57 *	is completely incompatible with the shared bus model
 58 *  - READY ... transfers may proceed when they shouldn't.
 59 *
 60 * REVISIT should changing those flags be privileged?
 61 */
 62#define SPI_MODE_MASK		(SPI_MODE_X_MASK | SPI_CS_HIGH \
 63				| SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
 64				| SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
 65				| SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL \
 66				| SPI_RX_QUAD | SPI_RX_OCTAL \
 67				| SPI_RX_CPHA_FLIP)
 
 68
 69struct spidev_data {
 70	dev_t			devt;
 71	struct mutex		spi_lock;
 72	struct spi_device	*spi;
 73	struct list_head	device_entry;
 74
 75	/* TX/RX buffers are NULL unless this device is open (users > 0) */
 76	struct mutex		buf_lock;
 77	unsigned		users;
 78	u8			*tx_buffer;
 79	u8			*rx_buffer;
 80	u32			speed_hz;
 81};
 82
 83static LIST_HEAD(device_list);
 84static DEFINE_MUTEX(device_list_lock);
 85
 86static unsigned bufsiz = 4096;
 87module_param(bufsiz, uint, S_IRUGO);
 88MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
 89
 90/*-------------------------------------------------------------------------*/
 91
 92static ssize_t
 93spidev_sync_unlocked(struct spi_device *spi, struct spi_message *message)
 94{
 95	ssize_t status;
 96
 97	status = spi_sync(spi, message);
 98	if (status == 0)
 99		status = message->actual_length;
100
101	return status;
102}
103
104static ssize_t
105spidev_sync(struct spidev_data *spidev, struct spi_message *message)
106{
107	ssize_t status;
108	struct spi_device *spi;
109
110	mutex_lock(&spidev->spi_lock);
111	spi = spidev->spi;
112
113	if (spi == NULL)
114		status = -ESHUTDOWN;
115	else
116		status = spidev_sync_unlocked(spi, message);
117
118	mutex_unlock(&spidev->spi_lock);
119
120	return status;
121}
122
123static inline ssize_t
124spidev_sync_write(struct spidev_data *spidev, size_t len)
125{
126	struct spi_transfer	t = {
127			.tx_buf		= spidev->tx_buffer,
128			.len		= len,
129			.speed_hz	= spidev->speed_hz,
130		};
131	struct spi_message	m;
132
133	spi_message_init(&m);
134	spi_message_add_tail(&t, &m);
135	return spidev_sync(spidev, &m);
136}
137
138static inline ssize_t
139spidev_sync_read(struct spidev_data *spidev, size_t len)
140{
141	struct spi_transfer	t = {
142			.rx_buf		= spidev->rx_buffer,
143			.len		= len,
144			.speed_hz	= spidev->speed_hz,
145		};
146	struct spi_message	m;
147
148	spi_message_init(&m);
149	spi_message_add_tail(&t, &m);
150	return spidev_sync(spidev, &m);
151}
152
153/*-------------------------------------------------------------------------*/
154
155/* Read-only message with current device setup */
156static ssize_t
157spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
158{
159	struct spidev_data	*spidev;
160	ssize_t			status;
161
162	/* chipselect only toggles at start or end of operation */
163	if (count > bufsiz)
164		return -EMSGSIZE;
165
166	spidev = filp->private_data;
167
168	mutex_lock(&spidev->buf_lock);
169	status = spidev_sync_read(spidev, count);
170	if (status > 0) {
171		unsigned long	missing;
172
173		missing = copy_to_user(buf, spidev->rx_buffer, status);
174		if (missing == status)
175			status = -EFAULT;
176		else
177			status = status - missing;
178	}
179	mutex_unlock(&spidev->buf_lock);
180
181	return status;
182}
183
184/* Write-only message with current device setup */
185static ssize_t
186spidev_write(struct file *filp, const char __user *buf,
187		size_t count, loff_t *f_pos)
188{
189	struct spidev_data	*spidev;
190	ssize_t			status;
191	unsigned long		missing;
192
193	/* chipselect only toggles at start or end of operation */
194	if (count > bufsiz)
195		return -EMSGSIZE;
196
197	spidev = filp->private_data;
198
199	mutex_lock(&spidev->buf_lock);
200	missing = copy_from_user(spidev->tx_buffer, buf, count);
201	if (missing == 0)
202		status = spidev_sync_write(spidev, count);
203	else
204		status = -EFAULT;
205	mutex_unlock(&spidev->buf_lock);
206
207	return status;
208}
209
210static int spidev_message(struct spidev_data *spidev,
211		struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
212{
213	struct spi_message	msg;
214	struct spi_transfer	*k_xfers;
215	struct spi_transfer	*k_tmp;
216	struct spi_ioc_transfer *u_tmp;
217	unsigned		n, total, tx_total, rx_total;
218	u8			*tx_buf, *rx_buf;
219	int			status = -EFAULT;
220
221	spi_message_init(&msg);
222	k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
223	if (k_xfers == NULL)
224		return -ENOMEM;
225
226	/* Construct spi_message, copying any tx data to bounce buffer.
227	 * We walk the array of user-provided transfers, using each one
228	 * to initialize a kernel version of the same transfer.
229	 */
230	tx_buf = spidev->tx_buffer;
231	rx_buf = spidev->rx_buffer;
232	total = 0;
233	tx_total = 0;
234	rx_total = 0;
235	for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
236			n;
237			n--, k_tmp++, u_tmp++) {
238		/* Ensure that also following allocations from rx_buf/tx_buf will meet
239		 * DMA alignment requirements.
240		 */
241		unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_KMALLOC_MINALIGN);
242
243		k_tmp->len = u_tmp->len;
244
245		total += k_tmp->len;
246		/* Since the function returns the total length of transfers
247		 * on success, restrict the total to positive int values to
248		 * avoid the return value looking like an error.  Also check
249		 * each transfer length to avoid arithmetic overflow.
250		 */
251		if (total > INT_MAX || k_tmp->len > INT_MAX) {
252			status = -EMSGSIZE;
253			goto done;
254		}
255
256		if (u_tmp->rx_buf) {
257			/* this transfer needs space in RX bounce buffer */
258			rx_total += len_aligned;
259			if (rx_total > bufsiz) {
260				status = -EMSGSIZE;
261				goto done;
262			}
263			k_tmp->rx_buf = rx_buf;
264			rx_buf += len_aligned;
265		}
266		if (u_tmp->tx_buf) {
267			/* this transfer needs space in TX bounce buffer */
268			tx_total += len_aligned;
269			if (tx_total > bufsiz) {
270				status = -EMSGSIZE;
271				goto done;
272			}
273			k_tmp->tx_buf = tx_buf;
274			if (copy_from_user(tx_buf, (const u8 __user *)
275						(uintptr_t) u_tmp->tx_buf,
276					u_tmp->len))
277				goto done;
278			tx_buf += len_aligned;
279		}
280
281		k_tmp->cs_change = !!u_tmp->cs_change;
282		k_tmp->tx_nbits = u_tmp->tx_nbits;
283		k_tmp->rx_nbits = u_tmp->rx_nbits;
284		k_tmp->bits_per_word = u_tmp->bits_per_word;
285		k_tmp->delay.value = u_tmp->delay_usecs;
286		k_tmp->delay.unit = SPI_DELAY_UNIT_USECS;
287		k_tmp->speed_hz = u_tmp->speed_hz;
288		k_tmp->word_delay.value = u_tmp->word_delay_usecs;
289		k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
290		if (!k_tmp->speed_hz)
291			k_tmp->speed_hz = spidev->speed_hz;
292#ifdef VERBOSE
293		dev_dbg(&spidev->spi->dev,
294			"  xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n",
295			k_tmp->len,
296			k_tmp->rx_buf ? "rx " : "",
297			k_tmp->tx_buf ? "tx " : "",
298			k_tmp->cs_change ? "cs " : "",
299			k_tmp->bits_per_word ? : spidev->spi->bits_per_word,
300			k_tmp->delay.value,
301			k_tmp->word_delay.value,
302			k_tmp->speed_hz ? : spidev->spi->max_speed_hz);
303#endif
304		spi_message_add_tail(k_tmp, &msg);
305	}
306
307	status = spidev_sync_unlocked(spidev->spi, &msg);
308	if (status < 0)
309		goto done;
310
311	/* copy any rx data out of bounce buffer */
312	for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
313			n;
314			n--, k_tmp++, u_tmp++) {
315		if (u_tmp->rx_buf) {
316			if (copy_to_user((u8 __user *)
317					(uintptr_t) u_tmp->rx_buf, k_tmp->rx_buf,
318					u_tmp->len)) {
319				status = -EFAULT;
320				goto done;
321			}
322		}
323	}
324	status = total;
325
326done:
327	kfree(k_xfers);
328	return status;
329}
330
331static struct spi_ioc_transfer *
332spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
333		unsigned *n_ioc)
334{
335	u32	tmp;
336
337	/* Check type, command number and direction */
338	if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC
339			|| _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
340			|| _IOC_DIR(cmd) != _IOC_WRITE)
341		return ERR_PTR(-ENOTTY);
342
343	tmp = _IOC_SIZE(cmd);
344	if ((tmp % sizeof(struct spi_ioc_transfer)) != 0)
345		return ERR_PTR(-EINVAL);
346	*n_ioc = tmp / sizeof(struct spi_ioc_transfer);
347	if (*n_ioc == 0)
348		return NULL;
349
350	/* copy into scratch area */
351	return memdup_user(u_ioc, tmp);
352}
353
354static long
355spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
356{
357	int			retval = 0;
358	struct spidev_data	*spidev;
359	struct spi_device	*spi;
 
360	u32			tmp;
361	unsigned		n_ioc;
362	struct spi_ioc_transfer	*ioc;
363
364	/* Check type and command number */
365	if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
366		return -ENOTTY;
367
368	/* guard against device removal before, or while,
369	 * we issue this ioctl.
370	 */
371	spidev = filp->private_data;
372	mutex_lock(&spidev->spi_lock);
373	spi = spi_dev_get(spidev->spi);
374	if (spi == NULL) {
375		mutex_unlock(&spidev->spi_lock);
376		return -ESHUTDOWN;
377	}
378
 
 
379	/* use the buffer lock here for triple duty:
380	 *  - prevent I/O (from us) so calling spi_setup() is safe;
381	 *  - prevent concurrent SPI_IOC_WR_* from morphing
382	 *    data fields while SPI_IOC_RD_* reads them;
383	 *  - SPI_IOC_MESSAGE needs the buffer locked "normally".
384	 */
385	mutex_lock(&spidev->buf_lock);
386
387	switch (cmd) {
388	/* read requests */
389	case SPI_IOC_RD_MODE:
390	case SPI_IOC_RD_MODE32:
391		tmp = spi->mode;
392
393		{
394			struct spi_controller *ctlr = spi->controller;
395
396			if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods &&
397			    ctlr->cs_gpiods[spi->chip_select])
398				tmp &= ~SPI_CS_HIGH;
399		}
400
401		if (cmd == SPI_IOC_RD_MODE)
402			retval = put_user(tmp & SPI_MODE_MASK,
403					  (__u8 __user *)arg);
404		else
405			retval = put_user(tmp & SPI_MODE_MASK,
406					  (__u32 __user *)arg);
407		break;
408	case SPI_IOC_RD_LSB_FIRST:
409		retval = put_user((spi->mode & SPI_LSB_FIRST) ?  1 : 0,
410					(__u8 __user *)arg);
411		break;
412	case SPI_IOC_RD_BITS_PER_WORD:
413		retval = put_user(spi->bits_per_word, (__u8 __user *)arg);
414		break;
415	case SPI_IOC_RD_MAX_SPEED_HZ:
416		retval = put_user(spidev->speed_hz, (__u32 __user *)arg);
417		break;
418
419	/* write requests */
420	case SPI_IOC_WR_MODE:
421	case SPI_IOC_WR_MODE32:
422		if (cmd == SPI_IOC_WR_MODE)
423			retval = get_user(tmp, (u8 __user *)arg);
424		else
425			retval = get_user(tmp, (u32 __user *)arg);
426		if (retval == 0) {
427			struct spi_controller *ctlr = spi->controller;
428			u32	save = spi->mode;
429
430			if (tmp & ~SPI_MODE_MASK) {
431				retval = -EINVAL;
432				break;
433			}
434
435			if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods &&
436			    ctlr->cs_gpiods[spi->chip_select])
437				tmp |= SPI_CS_HIGH;
438
439			tmp |= spi->mode & ~SPI_MODE_MASK;
440			spi->mode = tmp & SPI_MODE_USER_MASK;
441			retval = spi_setup(spi);
442			if (retval < 0)
443				spi->mode = save;
444			else
445				dev_dbg(&spi->dev, "spi mode %x\n", tmp);
446		}
447		break;
448	case SPI_IOC_WR_LSB_FIRST:
449		retval = get_user(tmp, (__u8 __user *)arg);
450		if (retval == 0) {
451			u32	save = spi->mode;
452
453			if (tmp)
454				spi->mode |= SPI_LSB_FIRST;
455			else
456				spi->mode &= ~SPI_LSB_FIRST;
457			retval = spi_setup(spi);
458			if (retval < 0)
459				spi->mode = save;
460			else
461				dev_dbg(&spi->dev, "%csb first\n",
462						tmp ? 'l' : 'm');
463		}
464		break;
465	case SPI_IOC_WR_BITS_PER_WORD:
466		retval = get_user(tmp, (__u8 __user *)arg);
467		if (retval == 0) {
468			u8	save = spi->bits_per_word;
469
470			spi->bits_per_word = tmp;
471			retval = spi_setup(spi);
472			if (retval < 0)
473				spi->bits_per_word = save;
474			else
475				dev_dbg(&spi->dev, "%d bits per word\n", tmp);
476		}
477		break;
478	case SPI_IOC_WR_MAX_SPEED_HZ: {
479		u32 save;
480
481		retval = get_user(tmp, (__u32 __user *)arg);
482		if (retval)
483			break;
484		if (tmp == 0) {
485			retval = -EINVAL;
486			break;
487		}
488
489		save = spi->max_speed_hz;
490
491		spi->max_speed_hz = tmp;
492		retval = spi_setup(spi);
493		if (retval == 0) {
494			spidev->speed_hz = tmp;
495			dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz);
496		}
497
498		spi->max_speed_hz = save;
499		break;
500	}
501	default:
502		/* segmented and/or full-duplex I/O request */
503		/* Check message and copy into scratch area */
504		ioc = spidev_get_ioc_message(cmd,
505				(struct spi_ioc_transfer __user *)arg, &n_ioc);
506		if (IS_ERR(ioc)) {
507			retval = PTR_ERR(ioc);
508			break;
509		}
510		if (!ioc)
511			break;	/* n_ioc is also 0 */
512
513		/* translate to spi_message, execute */
514		retval = spidev_message(spidev, ioc, n_ioc);
515		kfree(ioc);
516		break;
517	}
518
519	mutex_unlock(&spidev->buf_lock);
520	spi_dev_put(spi);
521	mutex_unlock(&spidev->spi_lock);
522	return retval;
523}
524
525#ifdef CONFIG_COMPAT
526static long
527spidev_compat_ioc_message(struct file *filp, unsigned int cmd,
528		unsigned long arg)
529{
530	struct spi_ioc_transfer __user	*u_ioc;
531	int				retval = 0;
532	struct spidev_data		*spidev;
533	struct spi_device		*spi;
534	unsigned			n_ioc, n;
535	struct spi_ioc_transfer		*ioc;
536
537	u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg);
538
539	/* guard against device removal before, or while,
540	 * we issue this ioctl.
541	 */
542	spidev = filp->private_data;
543	mutex_lock(&spidev->spi_lock);
544	spi = spi_dev_get(spidev->spi);
545	if (spi == NULL) {
546		mutex_unlock(&spidev->spi_lock);
547		return -ESHUTDOWN;
548	}
549
550	/* SPI_IOC_MESSAGE needs the buffer locked "normally" */
551	mutex_lock(&spidev->buf_lock);
552
553	/* Check message and copy into scratch area */
554	ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc);
555	if (IS_ERR(ioc)) {
556		retval = PTR_ERR(ioc);
557		goto done;
558	}
559	if (!ioc)
560		goto done;	/* n_ioc is also 0 */
561
562	/* Convert buffer pointers */
563	for (n = 0; n < n_ioc; n++) {
564		ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf);
565		ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf);
566	}
567
568	/* translate to spi_message, execute */
569	retval = spidev_message(spidev, ioc, n_ioc);
570	kfree(ioc);
571
572done:
573	mutex_unlock(&spidev->buf_lock);
574	spi_dev_put(spi);
575	mutex_unlock(&spidev->spi_lock);
576	return retval;
577}
578
579static long
580spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
581{
582	if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC
583			&& _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0))
584			&& _IOC_DIR(cmd) == _IOC_WRITE)
585		return spidev_compat_ioc_message(filp, cmd, arg);
586
587	return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
588}
589#else
590#define spidev_compat_ioctl NULL
591#endif /* CONFIG_COMPAT */
592
593static int spidev_open(struct inode *inode, struct file *filp)
594{
595	struct spidev_data	*spidev = NULL, *iter;
596	int			status = -ENXIO;
597
598	mutex_lock(&device_list_lock);
599
600	list_for_each_entry(iter, &device_list, device_entry) {
601		if (iter->devt == inode->i_rdev) {
602			status = 0;
603			spidev = iter;
604			break;
605		}
606	}
607
608	if (!spidev) {
609		pr_debug("spidev: nothing for minor %d\n", iminor(inode));
610		goto err_find_dev;
611	}
612
613	if (!spidev->tx_buffer) {
614		spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL);
615		if (!spidev->tx_buffer) {
616			status = -ENOMEM;
617			goto err_find_dev;
618		}
619	}
620
621	if (!spidev->rx_buffer) {
622		spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
623		if (!spidev->rx_buffer) {
624			status = -ENOMEM;
625			goto err_alloc_rx_buf;
626		}
627	}
628
629	spidev->users++;
630	filp->private_data = spidev;
631	stream_open(inode, filp);
632
633	mutex_unlock(&device_list_lock);
634	return 0;
635
636err_alloc_rx_buf:
637	kfree(spidev->tx_buffer);
638	spidev->tx_buffer = NULL;
639err_find_dev:
640	mutex_unlock(&device_list_lock);
641	return status;
642}
643
644static int spidev_release(struct inode *inode, struct file *filp)
645{
646	struct spidev_data	*spidev;
647	int			dofree;
648
649	mutex_lock(&device_list_lock);
650	spidev = filp->private_data;
651	filp->private_data = NULL;
652
653	mutex_lock(&spidev->spi_lock);
654	/* ... after we unbound from the underlying device? */
655	dofree = (spidev->spi == NULL);
656	mutex_unlock(&spidev->spi_lock);
657
658	/* last close? */
659	spidev->users--;
660	if (!spidev->users) {
661
662		kfree(spidev->tx_buffer);
663		spidev->tx_buffer = NULL;
664
665		kfree(spidev->rx_buffer);
666		spidev->rx_buffer = NULL;
667
668		if (dofree)
669			kfree(spidev);
670		else
671			spidev->speed_hz = spidev->spi->max_speed_hz;
672	}
673#ifdef CONFIG_SPI_SLAVE
674	if (!dofree)
675		spi_slave_abort(spidev->spi);
676#endif
677	mutex_unlock(&device_list_lock);
678
679	return 0;
680}
681
682static const struct file_operations spidev_fops = {
683	.owner =	THIS_MODULE,
684	/* REVISIT switch to aio primitives, so that userspace
685	 * gets more complete API coverage.  It'll simplify things
686	 * too, except for the locking.
687	 */
688	.write =	spidev_write,
689	.read =		spidev_read,
690	.unlocked_ioctl = spidev_ioctl,
691	.compat_ioctl = spidev_compat_ioctl,
692	.open =		spidev_open,
693	.release =	spidev_release,
694	.llseek =	no_llseek,
695};
696
697/*-------------------------------------------------------------------------*/
698
699/* The main reason to have this class is to make mdev/udev create the
700 * /dev/spidevB.C character device nodes exposing our userspace API.
701 * It also simplifies memory management.
702 */
703
704static struct class *spidev_class;
 
 
705
706static const struct spi_device_id spidev_spi_ids[] = {
 
707	{ .name = "dh2228fv" },
 
708	{ .name = "ltc2488" },
709	{ .name = "sx1301" },
710	{ .name = "bk4" },
711	{ .name = "dhcom-board" },
712	{ .name = "m53cpld" },
713	{ .name = "spi-petra" },
714	{ .name = "spi-authenta" },
 
 
715	{},
716};
717MODULE_DEVICE_TABLE(spi, spidev_spi_ids);
718
719/*
720 * spidev should never be referenced in DT without a specific compatible string,
721 * it is a Linux implementation thing rather than a description of the hardware.
722 */
723static int spidev_of_check(struct device *dev)
724{
725	if (device_property_match_string(dev, "compatible", "spidev") < 0)
726		return 0;
727
728	dev_err(dev, "spidev listed directly in DT is not supported\n");
729	return -EINVAL;
730}
731
732static const struct of_device_id spidev_dt_ids[] = {
733	{ .compatible = "rohm,dh2228fv", .data = &spidev_of_check },
 
 
734	{ .compatible = "lineartechnology,ltc2488", .data = &spidev_of_check },
735	{ .compatible = "semtech,sx1301", .data = &spidev_of_check },
736	{ .compatible = "lwn,bk4", .data = &spidev_of_check },
737	{ .compatible = "dh,dhcom-board", .data = &spidev_of_check },
738	{ .compatible = "menlo,m53cpld", .data = &spidev_of_check },
739	{ .compatible = "cisco,spi-petra", .data = &spidev_of_check },
740	{ .compatible = "micron,spi-authenta", .data = &spidev_of_check },
 
 
 
 
 
741	{},
742};
743MODULE_DEVICE_TABLE(of, spidev_dt_ids);
744
745/* Dummy SPI devices not to be used in production systems */
746static int spidev_acpi_check(struct device *dev)
747{
748	dev_warn(dev, "do not use this driver in production systems!\n");
749	return 0;
750}
751
752static const struct acpi_device_id spidev_acpi_ids[] = {
753	/*
754	 * The ACPI SPT000* devices are only meant for development and
755	 * testing. Systems used in production should have a proper ACPI
756	 * description of the connected peripheral and they should also use
757	 * a proper driver instead of poking directly to the SPI bus.
758	 */
759	{ "SPT0001", (kernel_ulong_t)&spidev_acpi_check },
760	{ "SPT0002", (kernel_ulong_t)&spidev_acpi_check },
761	{ "SPT0003", (kernel_ulong_t)&spidev_acpi_check },
762	{},
763};
764MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids);
765
766/*-------------------------------------------------------------------------*/
767
768static int spidev_probe(struct spi_device *spi)
769{
770	int (*match)(struct device *dev);
771	struct spidev_data	*spidev;
772	int			status;
773	unsigned long		minor;
774
775	match = device_get_match_data(&spi->dev);
776	if (match) {
777		status = match(&spi->dev);
778		if (status)
779			return status;
780	}
781
782	/* Allocate driver data */
783	spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
784	if (!spidev)
785		return -ENOMEM;
786
787	/* Initialize the driver data */
788	spidev->spi = spi;
789	mutex_init(&spidev->spi_lock);
790	mutex_init(&spidev->buf_lock);
791
792	INIT_LIST_HEAD(&spidev->device_entry);
793
794	/* If we can allocate a minor number, hook up this device.
795	 * Reusing minors is fine so long as udev or mdev is working.
796	 */
797	mutex_lock(&device_list_lock);
798	minor = find_first_zero_bit(minors, N_SPI_MINORS);
799	if (minor < N_SPI_MINORS) {
800		struct device *dev;
801
802		spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
803		dev = device_create(spidev_class, &spi->dev, spidev->devt,
804				    spidev, "spidev%d.%d",
805				    spi->master->bus_num, spi->chip_select);
806		status = PTR_ERR_OR_ZERO(dev);
807	} else {
808		dev_dbg(&spi->dev, "no minor number available!\n");
809		status = -ENODEV;
810	}
811	if (status == 0) {
812		set_bit(minor, minors);
813		list_add(&spidev->device_entry, &device_list);
814	}
815	mutex_unlock(&device_list_lock);
816
817	spidev->speed_hz = spi->max_speed_hz;
818
819	if (status == 0)
820		spi_set_drvdata(spi, spidev);
821	else
822		kfree(spidev);
823
824	return status;
825}
826
827static void spidev_remove(struct spi_device *spi)
828{
829	struct spidev_data	*spidev = spi_get_drvdata(spi);
830
831	/* prevent new opens */
832	mutex_lock(&device_list_lock);
833	/* make sure ops on existing fds can abort cleanly */
834	mutex_lock(&spidev->spi_lock);
835	spidev->spi = NULL;
836	mutex_unlock(&spidev->spi_lock);
837
838	list_del(&spidev->device_entry);
839	device_destroy(spidev_class, spidev->devt);
840	clear_bit(MINOR(spidev->devt), minors);
841	if (spidev->users == 0)
842		kfree(spidev);
843	mutex_unlock(&device_list_lock);
844}
845
846static struct spi_driver spidev_spi_driver = {
847	.driver = {
848		.name =		"spidev",
849		.of_match_table = spidev_dt_ids,
850		.acpi_match_table = spidev_acpi_ids,
851	},
852	.probe =	spidev_probe,
853	.remove =	spidev_remove,
854	.id_table =	spidev_spi_ids,
855
856	/* NOTE:  suspend/resume methods are not necessary here.
857	 * We don't do anything except pass the requests to/from
858	 * the underlying controller.  The refrigerator handles
859	 * most issues; the controller driver handles the rest.
860	 */
861};
862
863/*-------------------------------------------------------------------------*/
864
865static int __init spidev_init(void)
866{
867	int status;
868
869	/* Claim our 256 reserved device numbers.  Then register a class
870	 * that will key udev/mdev to add/remove /dev nodes.  Last, register
871	 * the driver which manages those device numbers.
872	 */
873	status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
874	if (status < 0)
875		return status;
876
877	spidev_class = class_create(THIS_MODULE, "spidev");
878	if (IS_ERR(spidev_class)) {
879		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
880		return PTR_ERR(spidev_class);
881	}
882
883	status = spi_register_driver(&spidev_spi_driver);
884	if (status < 0) {
885		class_destroy(spidev_class);
886		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
887	}
888	return status;
889}
890module_init(spidev_init);
891
892static void __exit spidev_exit(void)
893{
894	spi_unregister_driver(&spidev_spi_driver);
895	class_destroy(spidev_class);
896	unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
897}
898module_exit(spidev_exit);
899
900MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
901MODULE_DESCRIPTION("User mode SPI device interface");
902MODULE_LICENSE("GPL");
903MODULE_ALIAS("spi:spidev");