| // 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) |
| |
| 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; |
| } |
| |
| 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_KMALLOC_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(spidev, &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; |
| 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: |
| case SPI_IOC_RD_MODE32: |
| tmp = spi->mode; |
| |
| { |
| struct spi_controller *ctlr = spi->controller; |
| |
| if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods && |
| ctlr->cs_gpiods[spi->chip_select]) |
| tmp &= ~SPI_CS_HIGH; |
| } |
| |
| if (cmd == SPI_IOC_RD_MODE) |
| retval = put_user(tmp & SPI_MODE_MASK, |
| (__u8 __user *)arg); |
| else |
| retval = put_user(tmp & 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) { |
| struct spi_controller *ctlr = spi->controller; |
| u32 save = spi->mode; |
| |
| if (tmp & ~SPI_MODE_MASK) { |
| retval = -EINVAL; |
| break; |
| } |
| |
| if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods && |
| ctlr->cs_gpiods[spi->chip_select]) |
| 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); |
| 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; |
| 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; |
| } |
| |
| 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; |
| |
| spin_lock_irq(&spidev->spi_lock); |
| /* ... after we unbound from the underlying device? */ |
| dofree = (spidev->spi == NULL); |
| spin_unlock_irq(&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 struct class *spidev_class; |
| |
| 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" }, |
| {}, |
| }; |
| 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 = "rohm,dh2228fv", .data = &spidev_of_check }, |
| { .compatible = "lineartechnology,ltc2488", .data = &spidev_of_check }, |
| { .compatible = "semtech,sx1301", .data = &spidev_of_check }, |
| { .compatible = "lwn,bk4", .data = &spidev_of_check }, |
| { .compatible = "dh,dhcom-board", .data = &spidev_of_check }, |
| { .compatible = "menlo,m53cpld", .data = &spidev_of_check }, |
| { .compatible = "cisco,spi-petra", .data = &spidev_of_check }, |
| { .compatible = "micron,spi-authenta", .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; |
| 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; |
| } |
| |
| 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 */ |
| spin_lock_irq(&spidev->spi_lock); |
| spidev->spi = NULL; |
| spin_unlock_irq(&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; |
| |
| 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; |
| } |
| 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); |
| } |
| 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"); |