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Diffstat (limited to 'drivers/i2c/i2c-dev.c')
-rw-r--r--drivers/i2c/i2c-dev.c782
1 files changed, 782 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
new file mode 100644
index 000000000..dd35f341b
--- /dev/null
+++ b/drivers/i2c/i2c-dev.c
@@ -0,0 +1,782 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ i2c-dev.c - i2c-bus driver, char device interface
+
+ Copyright (C) 1995-97 Simon G. Vogl
+ Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
+ Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
+
+*/
+
+/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
+ But I have used so much of his original code and ideas that it seems
+ only fair to recognize him as co-author -- Frodo */
+
+/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cdev.h>
+#include <linux/compat.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/i2c-dev.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+/*
+ * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
+ * slave (i2c_client) with which messages will be exchanged. It's coupled
+ * with a character special file which is accessed by user mode drivers.
+ *
+ * The list of i2c_dev structures is parallel to the i2c_adapter lists
+ * maintained by the driver model, and is updated using bus notifications.
+ */
+struct i2c_dev {
+ struct list_head list;
+ struct i2c_adapter *adap;
+ struct device dev;
+ struct cdev cdev;
+};
+
+#define I2C_MINORS (MINORMASK + 1)
+static LIST_HEAD(i2c_dev_list);
+static DEFINE_SPINLOCK(i2c_dev_list_lock);
+
+static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
+{
+ struct i2c_dev *i2c_dev;
+
+ spin_lock(&i2c_dev_list_lock);
+ list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
+ if (i2c_dev->adap->nr == index)
+ goto found;
+ }
+ i2c_dev = NULL;
+found:
+ spin_unlock(&i2c_dev_list_lock);
+ return i2c_dev;
+}
+
+static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
+{
+ struct i2c_dev *i2c_dev;
+
+ if (adap->nr >= I2C_MINORS) {
+ pr_err("Out of device minors (%d)\n", adap->nr);
+ return ERR_PTR(-ENODEV);
+ }
+
+ i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
+ if (!i2c_dev)
+ return ERR_PTR(-ENOMEM);
+ i2c_dev->adap = adap;
+
+ spin_lock(&i2c_dev_list_lock);
+ list_add_tail(&i2c_dev->list, &i2c_dev_list);
+ spin_unlock(&i2c_dev_list_lock);
+ return i2c_dev;
+}
+
+static void put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev)
+{
+ spin_lock(&i2c_dev_list_lock);
+ list_del(&i2c_dev->list);
+ spin_unlock(&i2c_dev_list_lock);
+ if (del_cdev)
+ cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev);
+ put_device(&i2c_dev->dev);
+}
+
+static ssize_t name_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
+
+ if (!i2c_dev)
+ return -ENODEV;
+ return sysfs_emit(buf, "%s\n", i2c_dev->adap->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static struct attribute *i2c_attrs[] = {
+ &dev_attr_name.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(i2c);
+
+/* ------------------------------------------------------------------------- */
+
+/*
+ * After opening an instance of this character special file, a file
+ * descriptor starts out associated only with an i2c_adapter (and bus).
+ *
+ * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
+ * traffic to any devices on the bus used by that adapter. That's because
+ * the i2c_msg vectors embed all the addressing information they need, and
+ * are submitted directly to an i2c_adapter. However, SMBus-only adapters
+ * don't support that interface.
+ *
+ * To use read()/write() system calls on that file descriptor, or to use
+ * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
+ * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
+ * (never registered) i2c_client so it holds the addressing information
+ * needed by those system calls and by this SMBus interface.
+ */
+
+static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
+ loff_t *offset)
+{
+ char *tmp;
+ int ret;
+
+ struct i2c_client *client = file->private_data;
+
+ if (count > 8192)
+ count = 8192;
+
+ tmp = kzalloc(count, GFP_KERNEL);
+ if (tmp == NULL)
+ return -ENOMEM;
+
+ pr_debug("i2c-%d reading %zu bytes.\n", iminor(file_inode(file)), count);
+
+ ret = i2c_master_recv(client, tmp, count);
+ if (ret >= 0)
+ if (copy_to_user(buf, tmp, ret))
+ ret = -EFAULT;
+ kfree(tmp);
+ return ret;
+}
+
+static ssize_t i2cdev_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *offset)
+{
+ int ret;
+ char *tmp;
+ struct i2c_client *client = file->private_data;
+
+ if (count > 8192)
+ count = 8192;
+
+ tmp = memdup_user(buf, count);
+ if (IS_ERR(tmp))
+ return PTR_ERR(tmp);
+
+ pr_debug("i2c-%d writing %zu bytes.\n", iminor(file_inode(file)), count);
+
+ ret = i2c_master_send(client, tmp, count);
+ kfree(tmp);
+ return ret;
+}
+
+static int i2cdev_check(struct device *dev, void *addrp)
+{
+ struct i2c_client *client = i2c_verify_client(dev);
+
+ if (!client || client->addr != *(unsigned int *)addrp)
+ return 0;
+
+ return dev->driver ? -EBUSY : 0;
+}
+
+/* walk up mux tree */
+static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
+{
+ struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
+ int result;
+
+ result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
+ if (!result && parent)
+ result = i2cdev_check_mux_parents(parent, addr);
+
+ return result;
+}
+
+/* recurse down mux tree */
+static int i2cdev_check_mux_children(struct device *dev, void *addrp)
+{
+ int result;
+
+ if (dev->type == &i2c_adapter_type)
+ result = device_for_each_child(dev, addrp,
+ i2cdev_check_mux_children);
+ else
+ result = i2cdev_check(dev, addrp);
+
+ return result;
+}
+
+/* This address checking function differs from the one in i2c-core
+ in that it considers an address with a registered device, but no
+ driver bound to it, as NOT busy. */
+static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
+{
+ struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
+ int result = 0;
+
+ if (parent)
+ result = i2cdev_check_mux_parents(parent, addr);
+
+ if (!result)
+ result = device_for_each_child(&adapter->dev, &addr,
+ i2cdev_check_mux_children);
+
+ return result;
+}
+
+static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
+ unsigned nmsgs, struct i2c_msg *msgs)
+{
+ u8 __user **data_ptrs;
+ int i, res;
+
+ data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
+ if (data_ptrs == NULL) {
+ kfree(msgs);
+ return -ENOMEM;
+ }
+
+ res = 0;
+ for (i = 0; i < nmsgs; i++) {
+ /* Limit the size of the message to a sane amount */
+ if (msgs[i].len > 8192) {
+ res = -EINVAL;
+ break;
+ }
+
+ data_ptrs[i] = (u8 __user *)msgs[i].buf;
+ msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
+ if (IS_ERR(msgs[i].buf)) {
+ res = PTR_ERR(msgs[i].buf);
+ break;
+ }
+ /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
+ msgs[i].flags |= I2C_M_DMA_SAFE;
+
+ /*
+ * If the message length is received from the slave (similar
+ * to SMBus block read), we must ensure that the buffer will
+ * be large enough to cope with a message length of
+ * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
+ * drivers allow. The first byte in the buffer must be
+ * pre-filled with the number of extra bytes, which must be
+ * at least one to hold the message length, but can be
+ * greater (for example to account for a checksum byte at
+ * the end of the message.)
+ */
+ if (msgs[i].flags & I2C_M_RECV_LEN) {
+ if (!(msgs[i].flags & I2C_M_RD) ||
+ msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
+ msgs[i].len < msgs[i].buf[0] +
+ I2C_SMBUS_BLOCK_MAX) {
+ i++;
+ res = -EINVAL;
+ break;
+ }
+
+ msgs[i].len = msgs[i].buf[0];
+ }
+ }
+ if (res < 0) {
+ int j;
+ for (j = 0; j < i; ++j)
+ kfree(msgs[j].buf);
+ kfree(data_ptrs);
+ kfree(msgs);
+ return res;
+ }
+
+ res = i2c_transfer(client->adapter, msgs, nmsgs);
+ while (i-- > 0) {
+ if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
+ if (copy_to_user(data_ptrs[i], msgs[i].buf,
+ msgs[i].len))
+ res = -EFAULT;
+ }
+ kfree(msgs[i].buf);
+ }
+ kfree(data_ptrs);
+ kfree(msgs);
+ return res;
+}
+
+static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
+ u8 read_write, u8 command, u32 size,
+ union i2c_smbus_data __user *data)
+{
+ union i2c_smbus_data temp = {};
+ int datasize, res;
+
+ if ((size != I2C_SMBUS_BYTE) &&
+ (size != I2C_SMBUS_QUICK) &&
+ (size != I2C_SMBUS_BYTE_DATA) &&
+ (size != I2C_SMBUS_WORD_DATA) &&
+ (size != I2C_SMBUS_PROC_CALL) &&
+ (size != I2C_SMBUS_BLOCK_DATA) &&
+ (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
+ (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
+ (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
+ dev_dbg(&client->adapter->dev,
+ "size out of range (%x) in ioctl I2C_SMBUS.\n",
+ size);
+ return -EINVAL;
+ }
+ /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
+ so the check is valid if size==I2C_SMBUS_QUICK too. */
+ if ((read_write != I2C_SMBUS_READ) &&
+ (read_write != I2C_SMBUS_WRITE)) {
+ dev_dbg(&client->adapter->dev,
+ "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
+ read_write);
+ return -EINVAL;
+ }
+
+ /* Note that command values are always valid! */
+
+ if ((size == I2C_SMBUS_QUICK) ||
+ ((size == I2C_SMBUS_BYTE) &&
+ (read_write == I2C_SMBUS_WRITE)))
+ /* These are special: we do not use data */
+ return i2c_smbus_xfer(client->adapter, client->addr,
+ client->flags, read_write,
+ command, size, NULL);
+
+ if (data == NULL) {
+ dev_dbg(&client->adapter->dev,
+ "data is NULL pointer in ioctl I2C_SMBUS.\n");
+ return -EINVAL;
+ }
+
+ if ((size == I2C_SMBUS_BYTE_DATA) ||
+ (size == I2C_SMBUS_BYTE))
+ datasize = sizeof(data->byte);
+ else if ((size == I2C_SMBUS_WORD_DATA) ||
+ (size == I2C_SMBUS_PROC_CALL))
+ datasize = sizeof(data->word);
+ else /* size == smbus block, i2c block, or block proc. call */
+ datasize = sizeof(data->block);
+
+ if ((size == I2C_SMBUS_PROC_CALL) ||
+ (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
+ (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
+ (read_write == I2C_SMBUS_WRITE)) {
+ if (copy_from_user(&temp, data, datasize))
+ return -EFAULT;
+ }
+ if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
+ /* Convert old I2C block commands to the new
+ convention. This preserves binary compatibility. */
+ size = I2C_SMBUS_I2C_BLOCK_DATA;
+ if (read_write == I2C_SMBUS_READ)
+ temp.block[0] = I2C_SMBUS_BLOCK_MAX;
+ }
+ res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
+ read_write, command, size, &temp);
+ if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
+ (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
+ (read_write == I2C_SMBUS_READ))) {
+ if (copy_to_user(data, &temp, datasize))
+ return -EFAULT;
+ }
+ return res;
+}
+
+static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct i2c_client *client = file->private_data;
+ unsigned long funcs;
+
+ dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
+ cmd, arg);
+
+ switch (cmd) {
+ case I2C_SLAVE:
+ case I2C_SLAVE_FORCE:
+ if ((arg > 0x3ff) ||
+ (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
+ return -EINVAL;
+ if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
+ return -EBUSY;
+ /* REVISIT: address could become busy later */
+ client->addr = arg;
+ return 0;
+ case I2C_TENBIT:
+ if (arg)
+ client->flags |= I2C_M_TEN;
+ else
+ client->flags &= ~I2C_M_TEN;
+ return 0;
+ case I2C_PEC:
+ /*
+ * Setting the PEC flag here won't affect kernel drivers,
+ * which will be using the i2c_client node registered with
+ * the driver model core. Likewise, when that client has
+ * the PEC flag already set, the i2c-dev driver won't see
+ * (or use) this setting.
+ */
+ if (arg)
+ client->flags |= I2C_CLIENT_PEC;
+ else
+ client->flags &= ~I2C_CLIENT_PEC;
+ return 0;
+ case I2C_FUNCS:
+ funcs = i2c_get_functionality(client->adapter);
+ return put_user(funcs, (unsigned long __user *)arg);
+
+ case I2C_RDWR: {
+ struct i2c_rdwr_ioctl_data rdwr_arg;
+ struct i2c_msg *rdwr_pa;
+
+ if (copy_from_user(&rdwr_arg,
+ (struct i2c_rdwr_ioctl_data __user *)arg,
+ sizeof(rdwr_arg)))
+ return -EFAULT;
+
+ if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
+ return -EINVAL;
+
+ /*
+ * Put an arbitrary limit on the number of messages that can
+ * be sent at once
+ */
+ if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
+ return -EINVAL;
+
+ rdwr_pa = memdup_array_user(rdwr_arg.msgs,
+ rdwr_arg.nmsgs, sizeof(struct i2c_msg));
+ if (IS_ERR(rdwr_pa))
+ return PTR_ERR(rdwr_pa);
+
+ return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
+ }
+
+ case I2C_SMBUS: {
+ struct i2c_smbus_ioctl_data data_arg;
+ if (copy_from_user(&data_arg,
+ (struct i2c_smbus_ioctl_data __user *) arg,
+ sizeof(struct i2c_smbus_ioctl_data)))
+ return -EFAULT;
+ return i2cdev_ioctl_smbus(client, data_arg.read_write,
+ data_arg.command,
+ data_arg.size,
+ data_arg.data);
+ }
+ case I2C_RETRIES:
+ if (arg > INT_MAX)
+ return -EINVAL;
+
+ client->adapter->retries = arg;
+ break;
+ case I2C_TIMEOUT:
+ if (arg > INT_MAX)
+ return -EINVAL;
+
+ /* For historical reasons, user-space sets the timeout
+ * value in units of 10 ms.
+ */
+ client->adapter->timeout = msecs_to_jiffies(arg * 10);
+ break;
+ default:
+ /* NOTE: returning a fault code here could cause trouble
+ * in buggy userspace code. Some old kernel bugs returned
+ * zero in this case, and userspace code might accidentally
+ * have depended on that bug.
+ */
+ return -ENOTTY;
+ }
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+
+struct i2c_smbus_ioctl_data32 {
+ u8 read_write;
+ u8 command;
+ u32 size;
+ compat_caddr_t data; /* union i2c_smbus_data *data */
+};
+
+struct i2c_msg32 {
+ u16 addr;
+ u16 flags;
+ u16 len;
+ compat_caddr_t buf;
+};
+
+struct i2c_rdwr_ioctl_data32 {
+ compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
+ u32 nmsgs;
+};
+
+static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct i2c_client *client = file->private_data;
+ unsigned long funcs;
+ switch (cmd) {
+ case I2C_FUNCS:
+ funcs = i2c_get_functionality(client->adapter);
+ return put_user(funcs, (compat_ulong_t __user *)arg);
+ case I2C_RDWR: {
+ struct i2c_rdwr_ioctl_data32 rdwr_arg;
+ struct i2c_msg32 __user *p;
+ struct i2c_msg *rdwr_pa;
+ int i;
+
+ if (copy_from_user(&rdwr_arg,
+ (struct i2c_rdwr_ioctl_data32 __user *)arg,
+ sizeof(rdwr_arg)))
+ return -EFAULT;
+
+ if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
+ return -EINVAL;
+
+ if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
+ return -EINVAL;
+
+ rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
+ GFP_KERNEL);
+ if (!rdwr_pa)
+ return -ENOMEM;
+
+ p = compat_ptr(rdwr_arg.msgs);
+ for (i = 0; i < rdwr_arg.nmsgs; i++) {
+ struct i2c_msg32 umsg;
+ if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
+ kfree(rdwr_pa);
+ return -EFAULT;
+ }
+ rdwr_pa[i] = (struct i2c_msg) {
+ .addr = umsg.addr,
+ .flags = umsg.flags,
+ .len = umsg.len,
+ .buf = (__force __u8 *)compat_ptr(umsg.buf),
+ };
+ }
+
+ return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
+ }
+ case I2C_SMBUS: {
+ struct i2c_smbus_ioctl_data32 data32;
+ if (copy_from_user(&data32,
+ (void __user *) arg,
+ sizeof(data32)))
+ return -EFAULT;
+ return i2cdev_ioctl_smbus(client, data32.read_write,
+ data32.command,
+ data32.size,
+ compat_ptr(data32.data));
+ }
+ default:
+ return i2cdev_ioctl(file, cmd, arg);
+ }
+}
+#else
+#define compat_i2cdev_ioctl NULL
+#endif
+
+static int i2cdev_open(struct inode *inode, struct file *file)
+{
+ unsigned int minor = iminor(inode);
+ struct i2c_client *client;
+ struct i2c_adapter *adap;
+
+ adap = i2c_get_adapter(minor);
+ if (!adap)
+ return -ENODEV;
+
+ /* This creates an anonymous i2c_client, which may later be
+ * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
+ *
+ * This client is ** NEVER REGISTERED ** with the driver model
+ * or I2C core code!! It just holds private copies of addressing
+ * information and maybe a PEC flag.
+ */
+ client = kzalloc(sizeof(*client), GFP_KERNEL);
+ if (!client) {
+ i2c_put_adapter(adap);
+ return -ENOMEM;
+ }
+ snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
+
+ client->adapter = adap;
+ file->private_data = client;
+
+ return 0;
+}
+
+static int i2cdev_release(struct inode *inode, struct file *file)
+{
+ struct i2c_client *client = file->private_data;
+
+ i2c_put_adapter(client->adapter);
+ kfree(client);
+ file->private_data = NULL;
+
+ return 0;
+}
+
+static const struct file_operations i2cdev_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = i2cdev_read,
+ .write = i2cdev_write,
+ .unlocked_ioctl = i2cdev_ioctl,
+ .compat_ioctl = compat_i2cdev_ioctl,
+ .open = i2cdev_open,
+ .release = i2cdev_release,
+};
+
+/* ------------------------------------------------------------------------- */
+
+static struct class *i2c_dev_class;
+
+static void i2cdev_dev_release(struct device *dev)
+{
+ struct i2c_dev *i2c_dev;
+
+ i2c_dev = container_of(dev, struct i2c_dev, dev);
+ kfree(i2c_dev);
+}
+
+static int i2cdev_attach_adapter(struct device *dev, void *dummy)
+{
+ struct i2c_adapter *adap;
+ struct i2c_dev *i2c_dev;
+ int res;
+
+ if (dev->type != &i2c_adapter_type)
+ return 0;
+ adap = to_i2c_adapter(dev);
+
+ i2c_dev = get_free_i2c_dev(adap);
+ if (IS_ERR(i2c_dev))
+ return PTR_ERR(i2c_dev);
+
+ cdev_init(&i2c_dev->cdev, &i2cdev_fops);
+ i2c_dev->cdev.owner = THIS_MODULE;
+
+ device_initialize(&i2c_dev->dev);
+ i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
+ i2c_dev->dev.class = i2c_dev_class;
+ i2c_dev->dev.parent = &adap->dev;
+ i2c_dev->dev.release = i2cdev_dev_release;
+
+ res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
+ if (res)
+ goto err_put_i2c_dev;
+
+ res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
+ if (res)
+ goto err_put_i2c_dev;
+
+ pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
+ return 0;
+
+err_put_i2c_dev:
+ put_i2c_dev(i2c_dev, false);
+ return res;
+}
+
+static int i2cdev_detach_adapter(struct device *dev, void *dummy)
+{
+ struct i2c_adapter *adap;
+ struct i2c_dev *i2c_dev;
+
+ if (dev->type != &i2c_adapter_type)
+ return 0;
+ adap = to_i2c_adapter(dev);
+
+ i2c_dev = i2c_dev_get_by_minor(adap->nr);
+ if (!i2c_dev) /* attach_adapter must have failed */
+ return 0;
+
+ put_i2c_dev(i2c_dev, true);
+
+ pr_debug("adapter [%s] unregistered\n", adap->name);
+ return 0;
+}
+
+static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
+ void *data)
+{
+ struct device *dev = data;
+
+ switch (action) {
+ case BUS_NOTIFY_ADD_DEVICE:
+ return i2cdev_attach_adapter(dev, NULL);
+ case BUS_NOTIFY_DEL_DEVICE:
+ return i2cdev_detach_adapter(dev, NULL);
+ }
+
+ return 0;
+}
+
+static struct notifier_block i2cdev_notifier = {
+ .notifier_call = i2cdev_notifier_call,
+};
+
+/* ------------------------------------------------------------------------- */
+
+/*
+ * module load/unload record keeping
+ */
+
+static int __init i2c_dev_init(void)
+{
+ int res;
+
+ pr_info("i2c /dev entries driver\n");
+
+ res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
+ if (res)
+ goto out;
+
+ i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
+ if (IS_ERR(i2c_dev_class)) {
+ res = PTR_ERR(i2c_dev_class);
+ goto out_unreg_chrdev;
+ }
+ i2c_dev_class->dev_groups = i2c_groups;
+
+ /* Keep track of adapters which will be added or removed later */
+ res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
+ if (res)
+ goto out_unreg_class;
+
+ /* Bind to already existing adapters right away */
+ i2c_for_each_dev(NULL, i2cdev_attach_adapter);
+
+ return 0;
+
+out_unreg_class:
+ class_destroy(i2c_dev_class);
+out_unreg_chrdev:
+ unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
+out:
+ pr_err("Driver Initialisation failed\n");
+ return res;
+}
+
+static void __exit i2c_dev_exit(void)
+{
+ bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
+ i2c_for_each_dev(NULL, i2cdev_detach_adapter);
+ class_destroy(i2c_dev_class);
+ unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
+}
+
+MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
+MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
+MODULE_DESCRIPTION("I2C /dev entries driver");
+MODULE_LICENSE("GPL");
+
+module_init(i2c_dev_init);
+module_exit(i2c_dev_exit);
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-08 11:59:47 +0000