linux/drivers/spi/spidev.c
Uwe Kleine-König d934cd6f0e
spi: spidev: Follow renaming of SPI "master" to "controller"
In commit 8caab75fd2 ("spi: Generalize SPI "master" to "controller"")
some functions and struct members were renamed. To not break all drivers
compatibility macros were provided.

To be able to remove these compatibility macros push the renaming into
this driver.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/15ebfdf58a6590962bdd51b49b2e85a69b3bf443.1707324794.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2024-02-08 11:54:53 +00:00

904 lines
23 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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)
*/
#include <linux/init.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/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/compat.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);
static_assert(N_SPI_MINORS > 0 && N_SPI_MINORS <= 256);
/* 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_MODE_X_MASK | SPI_CS_HIGH \
| SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
| SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
| SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL \
| SPI_RX_QUAD | SPI_RX_OCTAL \
| SPI_RX_CPHA_FLIP | SPI_3WIRE_HIZ \
| SPI_MOSI_IDLE_LOW)
struct spidev_data {
dev_t devt;
struct mutex 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_unlocked(struct spi_device *spi, struct spi_message *message)
{
ssize_t status;
status = spi_sync(spi, message);
if (status == 0)
status = message->actual_length;
return status;
}
static ssize_t
spidev_sync(struct spidev_data *spidev, struct spi_message *message)
{
ssize_t status;
struct spi_device *spi;
mutex_lock(&spidev->spi_lock);
spi = spidev->spi;
if (spi == NULL)
status = -ESHUTDOWN;
else
status = spidev_sync_unlocked(spi, message);
mutex_unlock(&spidev->spi_lock);
return status;
}
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);
}
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);
}
/*-------------------------------------------------------------------------*/
/* 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;
/* 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;
}
/* 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;
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;
}
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++) {
/* Ensure that also following allocations from rx_buf/tx_buf will meet
* DMA alignment requirements.
*/
unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_DMA_MINALIGN);
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 += len_aligned;
if (rx_total > bufsiz) {
status = -EMSGSIZE;
goto done;
}
k_tmp->rx_buf = rx_buf;
rx_buf += len_aligned;
}
if (u_tmp->tx_buf) {
/* this transfer needs space in TX bounce buffer */
tx_total += len_aligned;
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 += len_aligned;
}
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.value = u_tmp->delay_usecs;
k_tmp->delay.unit = SPI_DELAY_UNIT_USECS;
k_tmp->speed_hz = u_tmp->speed_hz;
k_tmp->word_delay.value = u_tmp->word_delay_usecs;
k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
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 %u usec %uHz\n",
k_tmp->len,
k_tmp->rx_buf ? "rx " : "",
k_tmp->tx_buf ? "tx " : "",
k_tmp->cs_change ? "cs " : "",
k_tmp->bits_per_word ? : spidev->spi->bits_per_word,
k_tmp->delay.value,
k_tmp->word_delay.value,
k_tmp->speed_hz ? : spidev->spi->max_speed_hz);
#endif
spi_message_add_tail(k_tmp, &msg);
}
status = spidev_sync_unlocked(spidev->spi, &msg);
if (status < 0)
goto done;
/* copy any rx data out of bounce buffer */
for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
n;
n--, k_tmp++, u_tmp++) {
if (u_tmp->rx_buf) {
if (copy_to_user((u8 __user *)
(uintptr_t) u_tmp->rx_buf, k_tmp->rx_buf,
u_tmp->len)) {
status = -EFAULT;
goto done;
}
}
}
status = total;
done:
kfree(k_xfers);
return status;
}
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);
}
static long
spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
int retval = 0;
struct spidev_data *spidev;
struct spi_device *spi;
struct spi_controller *ctlr;
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;
mutex_lock(&spidev->spi_lock);
spi = spi_dev_get(spidev->spi);
if (spi == NULL) {
mutex_unlock(&spidev->spi_lock);
return -ESHUTDOWN;
}
ctlr = spi->controller;
/* 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:
case SPI_IOC_RD_MODE32:
tmp = spi->mode & SPI_MODE_MASK;
if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0))
tmp &= ~SPI_CS_HIGH;
if (cmd == SPI_IOC_RD_MODE)
retval = put_user(tmp, (__u8 __user *)arg);
else
retval = put_user(tmp, (__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;
}
if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0))
tmp |= SPI_CS_HIGH;
tmp |= spi->mode & ~SPI_MODE_MASK;
spi->mode = tmp & SPI_MODE_USER_MASK;
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: {
u32 save;
retval = get_user(tmp, (__u32 __user *)arg);
if (retval)
break;
if (tmp == 0) {
retval = -EINVAL;
break;
}
save = spi->max_speed_hz;
spi->max_speed_hz = tmp;
retval = spi_setup(spi);
if (retval == 0) {
spidev->speed_hz = tmp;
dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz);
}
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);
mutex_unlock(&spidev->spi_lock);
return retval;
}
#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;
mutex_lock(&spidev->spi_lock);
spi = spi_dev_get(spidev->spi);
if (spi == NULL) {
mutex_unlock(&spidev->spi_lock);
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);
mutex_unlock(&spidev->spi_lock);
return retval;
}
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));
}
#else
#define spidev_compat_ioctl NULL
#endif /* CONFIG_COMPAT */
static int spidev_open(struct inode *inode, struct file *filp)
{
struct spidev_data *spidev = NULL, *iter;
int status = -ENXIO;
mutex_lock(&device_list_lock);
list_for_each_entry(iter, &device_list, device_entry) {
if (iter->devt == inode->i_rdev) {
status = 0;
spidev = iter;
break;
}
}
if (!spidev) {
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) {
status = -ENOMEM;
goto err_find_dev;
}
}
if (!spidev->rx_buffer) {
spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
if (!spidev->rx_buffer) {
status = -ENOMEM;
goto err_alloc_rx_buf;
}
}
spidev->users++;
filp->private_data = spidev;
stream_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;
}
static int spidev_release(struct inode *inode, struct file *filp)
{
struct spidev_data *spidev;
int dofree;
mutex_lock(&device_list_lock);
spidev = filp->private_data;
filp->private_data = NULL;
mutex_lock(&spidev->spi_lock);
/* ... after we unbound from the underlying device? */
dofree = (spidev->spi == NULL);
mutex_unlock(&spidev->spi_lock);
/* last close? */
spidev->users--;
if (!spidev->users) {
kfree(spidev->tx_buffer);
spidev->tx_buffer = NULL;
kfree(spidev->rx_buffer);
spidev->rx_buffer = NULL;
if (dofree)
kfree(spidev);
else
spidev->speed_hz = spidev->spi->max_speed_hz;
}
#ifdef CONFIG_SPI_SLAVE
if (!dofree)
spi_slave_abort(spidev->spi);
#endif
mutex_unlock(&device_list_lock);
return 0;
}
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 const struct class spidev_class = {
.name = "spidev",
};
static const struct spi_device_id spidev_spi_ids[] = {
{ .name = "dh2228fv" },
{ .name = "ltc2488" },
{ .name = "sx1301" },
{ .name = "bk4" },
{ .name = "dhcom-board" },
{ .name = "m53cpld" },
{ .name = "spi-petra" },
{ .name = "spi-authenta" },
{ .name = "em3581" },
{ .name = "si3210" },
{},
};
MODULE_DEVICE_TABLE(spi, spidev_spi_ids);
/*
* 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.
*/
static int spidev_of_check(struct device *dev)
{
if (device_property_match_string(dev, "compatible", "spidev") < 0)
return 0;
dev_err(dev, "spidev listed directly in DT is not supported\n");
return -EINVAL;
}
static const struct of_device_id spidev_dt_ids[] = {
{ .compatible = "cisco,spi-petra", .data = &spidev_of_check },
{ .compatible = "dh,dhcom-board", .data = &spidev_of_check },
{ .compatible = "lineartechnology,ltc2488", .data = &spidev_of_check },
{ .compatible = "lwn,bk4", .data = &spidev_of_check },
{ .compatible = "menlo,m53cpld", .data = &spidev_of_check },
{ .compatible = "micron,spi-authenta", .data = &spidev_of_check },
{ .compatible = "rohm,dh2228fv", .data = &spidev_of_check },
{ .compatible = "semtech,sx1301", .data = &spidev_of_check },
{ .compatible = "silabs,em3581", .data = &spidev_of_check },
{ .compatible = "silabs,si3210", .data = &spidev_of_check },
{},
};
MODULE_DEVICE_TABLE(of, spidev_dt_ids);
/* Dummy SPI devices not to be used in production systems */
static int spidev_acpi_check(struct device *dev)
{
dev_warn(dev, "do not use this driver in production systems!\n");
return 0;
}
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", (kernel_ulong_t)&spidev_acpi_check },
{ "SPT0002", (kernel_ulong_t)&spidev_acpi_check },
{ "SPT0003", (kernel_ulong_t)&spidev_acpi_check },
{},
};
MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids);
/*-------------------------------------------------------------------------*/
static int spidev_probe(struct spi_device *spi)
{
int (*match)(struct device *dev);
struct spidev_data *spidev;
int status;
unsigned long minor;
match = device_get_match_data(&spi->dev);
if (match) {
status = match(&spi->dev);
if (status)
return status;
}
/* Allocate driver data */
spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
if (!spidev)
return -ENOMEM;
/* Initialize the driver data */
spidev->spi = spi;
mutex_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->controller->bus_num, spi_get_chipselect(spi, 0));
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;
}
static void spidev_remove(struct spi_device *spi)
{
struct spidev_data *spidev = spi_get_drvdata(spi);
/* prevent new opens */
mutex_lock(&device_list_lock);
/* make sure ops on existing fds can abort cleanly */
mutex_lock(&spidev->spi_lock);
spidev->spi = NULL;
mutex_unlock(&spidev->spi_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);
}
static struct spi_driver spidev_spi_driver = {
.driver = {
.name = "spidev",
.of_match_table = spidev_dt_ids,
.acpi_match_table = spidev_acpi_ids,
},
.probe = spidev_probe,
.remove = spidev_remove,
.id_table = spidev_spi_ids,
/* 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.
*/
status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
if (status < 0)
return status;
status = class_register(&spidev_class);
if (status) {
unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
return status;
}
status = spi_register_driver(&spidev_spi_driver);
if (status < 0) {
class_unregister(&spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
}
return status;
}
module_init(spidev_init);
static void __exit spidev_exit(void)
{
spi_unregister_driver(&spidev_spi_driver);
class_unregister(&spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
}
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");