Release 4.14 drivers/spi/spidev.c

/*
 * Simple synchronous userspace interface to SPI devices
 *
 * Copyright (C) 2006 SWAPP
 *      Andrea Paterniani <a.paterniani@swapp-eng.it>
 * Copyright (C) 2007 David Brownell (simplification, cleanup)
 *
 * 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.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/ioctl.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/acpi.h>

#include <linux/spi/spi.h>
#include <linux/spi/spidev.h>

#include <linux/uaccess.h>


/*
 * This supports access to SPI devices using normal userspace I/O calls.
 * Note that while traditional UNIX/POSIX I/O semantics are half duplex,
 * and often mask message boundaries, full SPI support requires full duplex
 * transfers.  There are several kinds of internal message boundaries to
 * handle chipselect management and other protocol options.
 *
 * SPI has a character major number assigned.  We allocate minor numbers
 * dynamically using a bitmask.  You must use hotplug tools, such as udev
 * (or mdev with busybox) to create and destroy the /dev/spidevB.C device
 * nodes, since there is no fixed association of minor numbers with any
 * particular SPI bus or device.
 */

#define SPIDEV_MAJOR			153	
/* assigned */

#define N_SPI_MINORS			32	
/* ... up to 256 */

static DECLARE_BITMAP(minors, N_SPI_MINORS);


/* Bit masks for spi_device.mode management.  Note that incorrect
 * settings for some settings can cause *lots* of trouble for other
 * devices on a shared bus:
 *
 *  - CS_HIGH ... this device will be active when it shouldn't be
 *  - 3WIRE ... when active, it won't behave as it should
 *  - NO_CS ... there will be no explicit message boundaries; this
 *      is completely incompatible with the shared bus model
 *  - READY ... transfers may proceed when they shouldn't.
 *
 * REVISIT should changing those flags be privileged?
 */

#define SPI_MODE_MASK		(SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
                                | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
                                | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
                                | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)


struct spidev_data {
	
dev_t			devt;
	
spinlock_t		spi_lock;
	
struct spi_device	*spi;
	
struct list_head	device_entry;

	/* TX/RX buffers are NULL unless this device is open (users > 0) */
	
struct mutex		buf_lock;
	
unsigned		users;
	
u8			*tx_buffer;
	
u8			*rx_buffer;
	
u32			speed_hz;
};

static LIST_HEAD(device_list);
static DEFINE_MUTEX(device_list_lock);


static unsigned bufsiz = 4096;
module_param(bufsiz, uint, S_IRUGO);
MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");

/*-------------------------------------------------------------------------*/


static ssize_t

spidev_sync(struct spidev_data *spidev, struct spi_message *message)
{
	int status;
	struct spi_device *spi;

	spin_lock_irq(&spidev->spi_lock);
	spi = spidev->spi;
	spin_unlock_irq(&spidev->spi_lock);

	if (spi == NULL)
		status = -ESHUTDOWN;
	else
		status = spi_sync(spi, message);

	if (status == 0)
		status = message->actual_length;

	return status;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
David Brownell
65
79.27%
1
50.00%
Martin Sperl
17
20.73%
1
50.00%
Total
82
100.00%
2
100.00%


static inline ssize_t

spidev_sync_write(struct spidev_data *spidev, size_t len)
{
	struct spi_transfer	t = {
			.tx_buf		= spidev->tx_buffer,
			.len		= len,
			.speed_hz	= spidev->speed_hz,
                };
	struct spi_message	m;

	spi_message_init(&m);
	spi_message_add_tail(&t, &m);
	return spidev_sync(spidev, &m);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
David Brownell
60
88.24%
1
33.33%
Mark Brown
7
10.29%
1
33.33%
Ray Jui
1
1.47%
1
33.33%
Total
68
100.00%
3
100.00%


static inline ssize_t

spidev_sync_read(struct spidev_data *spidev, size_t len)
{
	struct spi_transfer	t = {
			.rx_buf		= spidev->rx_buffer,
			.len		= len,
			.speed_hz	= spidev->speed_hz,
                };
	struct spi_message	m;

	spi_message_init(&m);
	spi_message_add_tail(&t, &m);
	return spidev_sync(spidev, &m);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
David Brownell
60
88.24%
1
33.33%
Mark Brown
7
10.29%
1
33.33%
Ray Jui
1
1.47%
1
33.33%
Total
68
100.00%
3
100.00%

/*-------------------------------------------------------------------------*/

/* Read-only message with current device setup */

static ssize_t

spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
	struct spidev_data	*spidev;
	ssize_t			status = 0;

	/* chipselect only toggles at start or end of operation */
	if (count > bufsiz)
		return -EMSGSIZE;

	spidev = filp->private_data;

	mutex_lock(&spidev->buf_lock);
	status = spidev_sync_read(spidev, count);
	if (status > 0) {
		unsigned long	missing;

		missing = copy_to_user(buf, spidev->rx_buffer, status);
		if (missing == status)
			status = -EFAULT;
		else
			status = status - missing;
	}
	mutex_unlock(&spidev->buf_lock);

	return status;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
115
95.04%
1
25.00%
Sebastian Andrzej Siewior
4
3.31%
1
25.00%
Ray Jui
1
0.83%
1
25.00%
David Brownell
1
0.83%
1
25.00%
Total
121
100.00%
4
100.00%

/* Write-only message with current device setup */

static ssize_t

spidev_write(struct file *filp, const char __user *buf,
		size_t count, loff_t *f_pos)
{
	struct spidev_data	*spidev;
	ssize_t			status = 0;
	unsigned long		missing;

	/* chipselect only toggles at start or end of operation */
	if (count > bufsiz)
		return -EMSGSIZE;

	spidev = filp->private_data;

	mutex_lock(&spidev->buf_lock);
	missing = copy_from_user(spidev->tx_buffer, buf, count);
	if (missing == 0)
		status = spidev_sync_write(spidev, count);
	else
		status = -EFAULT;
	mutex_unlock(&spidev->buf_lock);

	return status;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
106
98.15%
1
33.33%
David Brownell
1
0.93%
1
33.33%
Ray Jui
1
0.93%
1
33.33%
Total
108
100.00%
3
100.00%



static int spidev_message(struct spidev_data *spidev,
		struct spi_ioc_transfer *u_xfers, unsigned n_xfers)
{
	struct spi_message	msg;
	struct spi_transfer	*k_xfers;
	struct spi_transfer	*k_tmp;
	struct spi_ioc_transfer *u_tmp;
	unsigned		n, total, tx_total, rx_total;
	u8			*tx_buf, *rx_buf;
	int			status = -EFAULT;

	spi_message_init(&msg);
	k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
	if (k_xfers == NULL)
		return -ENOMEM;

	/* Construct spi_message, copying any tx data to bounce buffer.
         * We walk the array of user-provided transfers, using each one
         * to initialize a kernel version of the same transfer.
         */
	tx_buf = spidev->tx_buffer;
	rx_buf = spidev->rx_buffer;
	total = 0;
	tx_total = 0;
	rx_total = 0;
	for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
			n;
			n--, k_tmp++, u_tmp++) {
		k_tmp->len = u_tmp->len;

		total += k_tmp->len;
		/* Since the function returns the total length of transfers
                 * on success, restrict the total to positive int values to
                 * avoid the return value looking like an error.  Also check
                 * each transfer length to avoid arithmetic overflow.
                 */
		if (total > INT_MAX || k_tmp->len > INT_MAX) {
			status = -EMSGSIZE;
			goto done;
		}

		if (u_tmp->rx_buf) {
			/* this transfer needs space in RX bounce buffer */
			rx_total += k_tmp->len;
			if (rx_total > bufsiz) {
				status = -EMSGSIZE;
				goto done;
			}
			k_tmp->rx_buf = rx_buf;
			rx_buf += k_tmp->len;
		}
		if (u_tmp->tx_buf) {
			/* this transfer needs space in TX bounce buffer */
			tx_total += k_tmp->len;
			if (tx_total > bufsiz) {
				status = -EMSGSIZE;
				goto done;
			}
			k_tmp->tx_buf = tx_buf;
			if (copy_from_user(tx_buf, (const u8 __user *)
						(uintptr_t) u_tmp->tx_buf,
					u_tmp->len))
				goto done;
			tx_buf += k_tmp->len;
		}

		k_tmp->cs_change = !!u_tmp->cs_change;
		k_tmp->tx_nbits = u_tmp->tx_nbits;
		k_tmp->rx_nbits = u_tmp->rx_nbits;
		k_tmp->bits_per_word = u_tmp->bits_per_word;
		k_tmp->delay_usecs = u_tmp->delay_usecs;
		k_tmp->speed_hz = u_tmp->speed_hz;
		if (!k_tmp->speed_hz)
			k_tmp->speed_hz = spidev->speed_hz;
#ifdef VERBOSE
		dev_dbg(&spidev->spi->dev,
			"  xfer len %u %s%s%s%dbits %u usec %uHz\n",
			u_tmp->len,
			u_tmp->rx_buf ? "rx " : "",
			u_tmp->tx_buf ? "tx " : "",
			u_tmp->cs_change ? "cs " : "",
			u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
			u_tmp->delay_usecs,
			u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
#endif
		spi_message_add_tail(k_tmp, &msg);
	}

	status = spidev_sync(spidev, &msg);
	if (status < 0)
		goto done;

	/* copy any rx data out of bounce buffer */
	rx_buf = spidev->rx_buffer;
	for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
		if (u_tmp->rx_buf) {
			if (copy_to_user((u8 __user *)
					(uintptr_t) u_tmp->rx_buf, rx_buf,
					u_tmp->len)) {
				status = -EFAULT;
				goto done;
			}
			rx_buf += u_tmp->len;
		}
	}
	status = total;

done:
	kfree(k_xfers);
	return status;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
377
69.30%
1
7.69%
Ian Abbott
74
13.60%
2
15.38%
Ray Jui
25
4.60%
1
7.69%
Domen Puncer
21
3.86%
1
7.69%
Geert Uytterhoeven
17
3.12%
2
15.38%
Mark Brown
15
2.76%
1
7.69%
Florian Fainelli
6
1.10%
1
7.69%
David Brownell
6
1.10%
2
15.38%
Al Viro
3
0.55%
2
15.38%
Total
544
100.00%
13
100.00%


static struct spi_ioc_transfer *

spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
		unsigned *n_ioc)
{
	u32	tmp;

	/* Check type, command number and direction */
	if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC
			|| _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
			|| _IOC_DIR(cmd) != _IOC_WRITE)
		return ERR_PTR(-ENOTTY);

	tmp = _IOC_SIZE(cmd);
	if ((tmp % sizeof(struct spi_ioc_transfer)) != 0)
		return ERR_PTR(-EINVAL);
	*n_ioc = tmp / sizeof(struct spi_ioc_transfer);
	if (*n_ioc == 0)
		return NULL;

	/* copy into scratch area */
	return memdup_user(u_ioc, tmp);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ian Abbott
118
98.33%
1
33.33%
Andrea Paterniani
1
0.83%
1
33.33%
Geliang Tang
1
0.83%
1
33.33%
Total
120
100.00%
3
100.00%


static long

spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	int			retval = 0;
	struct spidev_data	*spidev;
	struct spi_device	*spi;
	u32			tmp;
	unsigned		n_ioc;
	struct spi_ioc_transfer	*ioc;

	/* Check type and command number */
	if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
		return -ENOTTY;

	/* guard against device removal before, or while,
         * we issue this ioctl.
         */
	spidev = filp->private_data;
	spin_lock_irq(&spidev->spi_lock);
	spi = spi_dev_get(spidev->spi);
	spin_unlock_irq(&spidev->spi_lock);

	if (spi == NULL)
		return -ESHUTDOWN;

	/* use the buffer lock here for triple duty:
         *  - prevent I/O (from us) so calling spi_setup() is safe;
         *  - prevent concurrent SPI_IOC_WR_* from morphing
         *    data fields while SPI_IOC_RD_* reads them;
         *  - SPI_IOC_MESSAGE needs the buffer locked "normally".
         */
	mutex_lock(&spidev->buf_lock);

	switch (cmd) {
	/* read requests */
	case SPI_IOC_RD_MODE:
		retval = put_user(spi->mode & SPI_MODE_MASK,
					(__u8 __user *)arg);
		break;
	case SPI_IOC_RD_MODE32:
		retval = put_user(spi->mode & SPI_MODE_MASK,
					(__u32 __user *)arg);
		break;
	case SPI_IOC_RD_LSB_FIRST:
		retval = put_user((spi->mode & SPI_LSB_FIRST) ?  1 : 0,
					(__u8 __user *)arg);
		break;
	case SPI_IOC_RD_BITS_PER_WORD:
		retval = put_user(spi->bits_per_word, (__u8 __user *)arg);
		break;
	case SPI_IOC_RD_MAX_SPEED_HZ:
		retval = put_user(spidev->speed_hz, (__u32 __user *)arg);
		break;

	/* write requests */
	case SPI_IOC_WR_MODE:
	case SPI_IOC_WR_MODE32:
		if (cmd == SPI_IOC_WR_MODE)
			retval = get_user(tmp, (u8 __user *)arg);
		else
			retval = get_user(tmp, (u32 __user *)arg);
		if (retval == 0) {
			u32	save = spi->mode;

			if (tmp & ~SPI_MODE_MASK) {
				retval = -EINVAL;
				break;
			}

			tmp |= spi->mode & ~SPI_MODE_MASK;
			spi->mode = (u16)tmp;
			retval = spi_setup(spi);
			if (retval < 0)
				spi->mode = save;
			else
				dev_dbg(&spi->dev, "spi mode %x\n", tmp);
		}
		break;
	case SPI_IOC_WR_LSB_FIRST:
		retval = get_user(tmp, (__u8 __user *)arg);
		if (retval == 0) {
			u32	save = spi->mode;

			if (tmp)
				spi->mode |= SPI_LSB_FIRST;
			else
				spi->mode &= ~SPI_LSB_FIRST;
			retval = spi_setup(spi);
			if (retval < 0)
				spi->mode = save;
			else
				dev_dbg(&spi->dev, "%csb first\n",
						tmp ? 'l' : 'm');
		}
		break;
	case SPI_IOC_WR_BITS_PER_WORD:
		retval = get_user(tmp, (__u8 __user *)arg);
		if (retval == 0) {
			u8	save = spi->bits_per_word;

			spi->bits_per_word = tmp;
			retval = spi_setup(spi);
			if (retval < 0)
				spi->bits_per_word = save;
			else
				dev_dbg(&spi->dev, "%d bits per word\n", tmp);
		}
		break;
	case SPI_IOC_WR_MAX_SPEED_HZ:
		retval = get_user(tmp, (__u32 __user *)arg);
		if (retval == 0) {
			u32	save = spi->max_speed_hz;

			spi->max_speed_hz = tmp;
			retval = spi_setup(spi);
			if (retval >= 0)
				spidev->speed_hz = tmp;
			else
				dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
			spi->max_speed_hz = save;
		}
		break;

	default:
		/* segmented and/or full-duplex I/O request */
		/* Check message and copy into scratch area */
		ioc = spidev_get_ioc_message(cmd,
				(struct spi_ioc_transfer __user *)arg, &n_ioc);
		if (IS_ERR(ioc)) {
			retval = PTR_ERR(ioc);
			break;
		}
		if (!ioc)
			break;	/* n_ioc is also 0 */

		/* translate to spi_message, execute */
		retval = spidev_message(spidev, ioc, n_ioc);
		kfree(ioc);
		break;
	}

	mutex_unlock(&spidev->buf_lock);
	spi_dev_put(spi);
	return retval;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
485
72.82%
1
12.50%
Ian Abbott
66
9.91%
1
12.50%
Geert Uytterhoeven
48
7.21%
2
25.00%
David Brownell
35
5.26%
1
12.50%
Mark Brown
12
1.80%
1
12.50%
Al Viro
10
1.50%
1
12.50%
Alan Cox
10
1.50%
1
12.50%
Total
666
100.00%
8
100.00%

#ifdef CONFIG_COMPAT

static long

spidev_compat_ioc_message(struct file *filp, unsigned int cmd,
		unsigned long arg)
{
	struct spi_ioc_transfer __user	*u_ioc;
	int				retval = 0;
	struct spidev_data		*spidev;
	struct spi_device		*spi;
	unsigned			n_ioc, n;
	struct spi_ioc_transfer		*ioc;

	u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg);

	/* guard against device removal before, or while,
         * we issue this ioctl.
         */
	spidev = filp->private_data;
	spin_lock_irq(&spidev->spi_lock);
	spi = spi_dev_get(spidev->spi);
	spin_unlock_irq(&spidev->spi_lock);

	if (spi == NULL)
		return -ESHUTDOWN;

	/* SPI_IOC_MESSAGE needs the buffer locked "normally" */
	mutex_lock(&spidev->buf_lock);

	/* Check message and copy into scratch area */
	ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc);
	if (IS_ERR(ioc)) {
		retval = PTR_ERR(ioc);
		goto done;
	}
	if (!ioc)
		goto done;	/* n_ioc is also 0 */

	/* Convert buffer pointers */
	for (n = 0; n < n_ioc; n++) {
		ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf);
		ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf);
	}

	/* translate to spi_message, execute */
	retval = spidev_message(spidev, ioc, n_ioc);
	kfree(ioc);

done:
	mutex_unlock(&spidev->buf_lock);
	spi_dev_put(spi);
	return retval;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ian Abbott
173
70.33%
1
20.00%
Andrea Paterniani
56
22.76%
1
20.00%
Alan Cox
8
3.25%
1
20.00%
David Brownell
5
2.03%
1
20.00%
Florin Malita
4
1.63%
1
20.00%
Total
246
100.00%
5
100.00%


static long

spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC
			&& _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0))
			&& _IOC_DIR(cmd) == _IOC_WRITE)
		return spidev_compat_ioc_message(filp, cmd, arg);

	return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Ian Abbott
39
52.00%
1
50.00%
Bernhard Walle
36
48.00%
1
50.00%
Total
75
100.00%
2
100.00%

#else

#define spidev_compat_ioctl NULL
#endif /* CONFIG_COMPAT */



static int spidev_open(struct inode *inode, struct file *filp)
{
	struct spidev_data	*spidev;
	int			status = -ENXIO;

	mutex_lock(&device_list_lock);

	list_for_each_entry(spidev, &device_list, device_entry) {
		if (spidev->devt == inode->i_rdev) {
			status = 0;
			break;
		}
	}

	if (status) {
		pr_debug("spidev: nothing for minor %d\n", iminor(inode));
		goto err_find_dev;
	}

	if (!spidev->tx_buffer) {
		spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL);
		if (!spidev->tx_buffer) {
			dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
			status = -ENOMEM;
			goto err_find_dev;
		}
	}

	if (!spidev->rx_buffer) {
		spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
		if (!spidev->rx_buffer) {
			dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
			status = -ENOMEM;
			goto err_alloc_rx_buf;
		}
	}

	spidev->users++;
	filp->private_data = spidev;
	nonseekable_open(inode, filp);

	mutex_unlock(&device_list_lock);
	return 0;

err_alloc_rx_buf:
	kfree(spidev->tx_buffer);
	spidev->tx_buffer = NULL;
err_find_dev:
	mutex_unlock(&device_list_lock);
	return status;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
143
62.17%
1
50.00%
Ray Jui
87
37.83%
1
50.00%
Total
230
100.00%
2
100.00%



static int spidev_release(struct inode *inode, struct file *filp)
{
	struct spidev_data	*spidev;

	mutex_lock(&device_list_lock);
	spidev = filp->private_data;
	filp->private_data = NULL;

	/* last close? */
	spidev->users--;
	if (!spidev->users) {
		int		dofree;

		kfree(spidev->tx_buffer);
		spidev->tx_buffer = NULL;

		kfree(spidev->rx_buffer);
		spidev->rx_buffer = NULL;

		spin_lock_irq(&spidev->spi_lock);
		if (spidev->spi)
			spidev->speed_hz = spidev->spi->max_speed_hz;

		/* ... after we unbound from the underlying device? */
		dofree = (spidev->spi == NULL);
		spin_unlock_irq(&spidev->spi_lock);

		if (dofree)
			kfree(spidev);
	}
	mutex_unlock(&device_list_lock);

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
72
50.00%
1
14.29%
David Brownell
32
22.22%
1
14.29%
Mark Brown
18
12.50%
2
28.57%
Ray Jui
15
10.42%
1
14.29%
Sudip Mukherjee
6
4.17%
1
14.29%
Fabio Estevam
1
0.69%
1
14.29%
Total
144
100.00%
7
100.00%


static const struct file_operations spidev_fops = {
	.owner =	THIS_MODULE,
	/* REVISIT switch to aio primitives, so that userspace
         * gets more complete API coverage.  It'll simplify things
         * too, except for the locking.
         */
	.write =	spidev_write,
	.read =		spidev_read,
	.unlocked_ioctl = spidev_ioctl,
	.compat_ioctl = spidev_compat_ioctl,
	.open =		spidev_open,
	.release =	spidev_release,
	.llseek =	no_llseek,
};

/*-------------------------------------------------------------------------*/

/* The main reason to have this class is to make mdev/udev create the
 * /dev/spidevB.C character device nodes exposing our userspace API.
 * It also simplifies memory management.
 */


static struct class *spidev_class;

#ifdef CONFIG_OF

static const struct of_device_id spidev_dt_ids[] = {
	{ .compatible = "rohm,dh2228fv" },
	{ .compatible = "lineartechnology,ltc2488" },
	{ .compatible = "ge,achc" },
	{ .compatible = "semtech,sx1301" },
	{},
};
MODULE_DEVICE_TABLE(of, spidev_dt_ids);
#endif

#ifdef CONFIG_ACPI

/* Dummy SPI devices not to be used in production systems */

#define SPIDEV_ACPI_DUMMY	1


static const struct acpi_device_id spidev_acpi_ids[] = {
	/*
         * The ACPI SPT000* devices are only meant for development and
         * testing. Systems used in production should have a proper ACPI
         * description of the connected peripheral and they should also use
         * a proper driver instead of poking directly to the SPI bus.
         */
	{ "SPT0001", SPIDEV_ACPI_DUMMY },
	{ "SPT0002", SPIDEV_ACPI_DUMMY },
	{ "SPT0003", SPIDEV_ACPI_DUMMY },
	{},
};
MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids);



static void spidev_probe_acpi(struct spi_device *spi)
{
	const struct acpi_device_id *id;

	if (!has_acpi_companion(&spi->dev))
		return;

	id = acpi_match_device(spidev_acpi_ids, &spi->dev);
	if (WARN_ON(!id))
		return;

	if (id->driver_data == SPIDEV_ACPI_DUMMY)
		dev_warn(&spi->dev, "do not use this driver in production systems!\n");
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mika Westerberg
68
100.00%
1
100.00%
Total
68
100.00%
1
100.00%

#else


static inline void spidev_probe_acpi(struct spi_device *spi) {}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mika Westerberg
11
100.00%
1
100.00%
Total
11
100.00%
1
100.00%

#endif

/*-------------------------------------------------------------------------*/



static int spidev_probe(struct spi_device *spi)
{
	struct spidev_data	*spidev;
	int			status;
	unsigned long		minor;

	/*
         * spidev should never be referenced in DT without a specific
         * compatible string, it is a Linux implementation thing
         * rather than a description of the hardware.
         */
	if (spi->dev.of_node && !of_match_device(spidev_dt_ids, &spi->dev)) {
		dev_err(&spi->dev, "buggy DT: spidev listed directly in DT\n");
		WARN_ON(spi->dev.of_node &&
			!of_match_device(spidev_dt_ids, &spi->dev));
	}

	spidev_probe_acpi(spi);

	/* Allocate driver data */
	spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
	if (!spidev)
		return -ENOMEM;

	/* Initialize the driver data */
	spidev->spi = spi;
	spin_lock_init(&spidev->spi_lock);
	mutex_init(&spidev->buf_lock);

	INIT_LIST_HEAD(&spidev->device_entry);

	/* If we can allocate a minor number, hook up this device.
         * Reusing minors is fine so long as udev or mdev is working.
         */
	mutex_lock(&device_list_lock);
	minor = find_first_zero_bit(minors, N_SPI_MINORS);
	if (minor < N_SPI_MINORS) {
		struct device *dev;

		spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
		dev = device_create(spidev_class, &spi->dev, spidev->devt,
				    spidev, "spidev%d.%d",
				    spi->master->bus_num, spi->chip_select);
		status = PTR_ERR_OR_ZERO(dev);
	} else {
		dev_dbg(&spi->dev, "no minor number available!\n");
		status = -ENODEV;
	}
	if (status == 0) {
		set_bit(minor, minors);
		list_add(&spidev->device_entry, &device_list);
	}
	mutex_unlock(&device_list_lock);

	spidev->speed_hz = spi->max_speed_hz;

	if (status == 0)
		spi_set_drvdata(spi, spidev);
	else
		kfree(spidev);

	return status;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
193
66.32%
1
8.33%
Mark Brown
59
20.27%
2
16.67%
David Brownell
21
7.22%
3
25.00%
Wolfgang Ocker
9
3.09%
1
8.33%
Mika Westerberg
5
1.72%
1
8.33%
Rusty Russell
1
0.34%
1
8.33%
Fabio Estevam
1
0.34%
1
8.33%
Domen Puncer
1
0.34%
1
8.33%
Greg Kroah-Hartman
1
0.34%
1
8.33%
Total
291
100.00%
12
100.00%



static int spidev_remove(struct spi_device *spi)
{
	struct spidev_data	*spidev = spi_get_drvdata(spi);

	/* make sure ops on existing fds can abort cleanly */
	spin_lock_irq(&spidev->spi_lock);
	spidev->spi = NULL;
	spin_unlock_irq(&spidev->spi_lock);

	/* prevent new opens */
	mutex_lock(&device_list_lock);
	list_del(&spidev->device_entry);
	device_destroy(spidev_class, spidev->devt);
	clear_bit(MINOR(spidev->devt), minors);
	if (spidev->users == 0)
		kfree(spidev);
	mutex_unlock(&device_list_lock);

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
67
65.69%
1
33.33%
David Brownell
35
34.31%
2
66.67%
Total
102
100.00%
3
100.00%


static struct spi_driver spidev_spi_driver = {
	.driver = {
		.name =		"spidev",
		.of_match_table = of_match_ptr(spidev_dt_ids),
		.acpi_match_table = ACPI_PTR(spidev_acpi_ids),
        },
	.probe =	spidev_probe,
	.remove =	spidev_remove,

	/* NOTE:  suspend/resume methods are not necessary here.
         * We don't do anything except pass the requests to/from
         * the underlying controller.  The refrigerator handles
         * most issues; the controller driver handles the rest.
         */
};

/*-------------------------------------------------------------------------*/



static int __init spidev_init(void)
{
	int status;

	/* Claim our 256 reserved device numbers.  Then register a class
         * that will key udev/mdev to add/remove /dev nodes.  Last, register
         * the driver which manages those device numbers.
         */
	BUILD_BUG_ON(N_SPI_MINORS > 256);
	status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
	if (status < 0)
		return status;

	spidev_class = class_create(THIS_MODULE, "spidev");
	if (IS_ERR(spidev_class)) {
		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
		return PTR_ERR(spidev_class);
	}

	status = spi_register_driver(&spidev_spi_driver);
	if (status < 0) {
		class_destroy(spidev_class);
		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
	}
	return status;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
94
84.68%
1
33.33%
David Brownell
14
12.61%
1
33.33%
Mike Frysinger
3
2.70%
1
33.33%
Total
111
100.00%
3
100.00%


module_init(spidev_init);



static void __exit spidev_exit(void)
{
	spi_unregister_driver(&spidev_spi_driver);
	class_destroy(spidev_class);
	unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
28
90.32%
1
33.33%
Mike Frysinger
2
6.45%
1
33.33%
David Brownell
1
3.23%
1
33.33%
Total
31
100.00%
3
100.00%


module_exit(spidev_exit);

MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
MODULE_DESCRIPTION("User mode SPI device interface");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:spidev");
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrea Paterniani
1952
56.01%
1
2.17%
Ian Abbott
473
13.57%
3
6.52%
David Brownell
346
9.93%
5
10.87%
Mark Brown
151
4.33%
3
6.52%
Mika Westerberg
144
4.13%
1
2.17%
Ray Jui
137
3.93%
1
2.17%
Geert Uytterhoeven
66
1.89%
3
6.52%
Bernhard Walle
53
1.52%
1
2.17%
Domen Puncer
22
0.63%
2
4.35%
Alan Cox
19
0.55%
1
2.17%
Martin Sperl
17
0.49%
1
2.17%
Al Viro
13
0.37%
2
4.35%
Maxime Ripard
12
0.34%
1
2.17%
Wolfgang Ocker
9
0.26%
1
2.17%
Jiri Prchal
7
0.20%
1
2.17%
Fabien Lahoudere
7
0.20%
1
2.17%
Ben Whitten
7
0.20%
1
2.17%
Sudip Mukherjee
6
0.17%
1
2.17%
Mike Frysinger
6
0.17%
1
2.17%
Florian Fainelli
6
0.17%
1
2.17%
Thadeu Lima de Souza Cascardo
5
0.14%
1
2.17%
Anton Vorontsov
5
0.14%
1
2.17%
Arnd Bergmann
5
0.14%
1
2.17%
Sebastian Andrzej Siewior
4
0.11%
1
2.17%
Florin Malita
4
0.11%
1
2.17%
Fabio Estevam
2
0.06%
2
4.35%
Greg Kroah-Hartman
1
0.03%
1
2.17%
Rusty Russell
1
0.03%
1
2.17%
Geliang Tang
1
0.03%
1
2.17%
Uwe Kleine-König
1
0.03%
1
2.17%
Jarkko Nikula
1
0.03%
1
2.17%
Jingoo Han
1
0.03%
1
2.17%
Alexey Dobriyan
1
0.03%
1
2.17%
Total
3485
100.00%
46
100.00%
Directory: drivers/spi

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.