industrialio-core.c

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/* The industrial I/O core
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * Based on elements of hwmon and input subsystems.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/kdev_t.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/anon_inodes.h>
#include <linux/debugfs.h>
#include <linux/iio/iio.h>
#include "iio_core.h"
#include "iio_core_trigger.h"
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>

/* IDA to assign each registered device a unique id */
static DEFINE_IDA(iio_ida);

static dev_t iio_devt;

#define IIO_DEV_MAX 256
struct bus_type iio_bus_type = {
    .name = "iio",
};
EXPORT_SYMBOL(iio_bus_type);

static struct dentry *iio_debugfs_dentry;

static const char * const iio_direction[] = {
    [0] = "in",
    [1] = "out",
};

static const char * const iio_chan_type_name_spec[] = {
    [IIO_VOLTAGE] = "voltage",
    [IIO_CURRENT] = "current",
    [IIO_POWER] = "power",
    [IIO_ACCEL] = "accel",
    [IIO_ANGL_VEL] = "anglvel",
    [IIO_MAGN] = "magn",
    [IIO_LIGHT] = "illuminance",
    [IIO_INTENSITY] = "intensity",
    [IIO_PROXIMITY] = "proximity",
    [IIO_TEMP] = "temp",
    [IIO_INCLI] = "incli",
    [IIO_ROT] = "rot",
    [IIO_ANGL] = "angl",
    [IIO_TIMESTAMP] = "timestamp",
    [IIO_CAPACITANCE] = "capacitance",
    [IIO_ALTVOLTAGE] = "altvoltage",
    [IIO_CCT] = "cct",
};

static const char * const iio_modifier_names[] = {
    [IIO_MOD_X] = "x",
    [IIO_MOD_Y] = "y",
    [IIO_MOD_Z] = "z",
    [IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
    [IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
    [IIO_MOD_LIGHT_BOTH] = "both",
    [IIO_MOD_LIGHT_IR] = "ir",
    [IIO_MOD_LIGHT_CLEAR] = "clear",
    [IIO_MOD_LIGHT_RED] = "red",
    [IIO_MOD_LIGHT_GREEN] = "green",
    [IIO_MOD_LIGHT_BLUE] = "blue",
};

/* relies on pairs of these shared then separate */
static const char * const iio_chan_info_postfix[] = {
    [IIO_CHAN_INFO_RAW] = "raw",
    [IIO_CHAN_INFO_PROCESSED] = "input",
    [IIO_CHAN_INFO_SCALE] = "scale",
    [IIO_CHAN_INFO_OFFSET] = "offset",
    [IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
    [IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
    [IIO_CHAN_INFO_PEAK] = "peak_raw",
    [IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
    [IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
    [IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
    [IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
    = "filter_low_pass_3db_frequency",
    [IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
    [IIO_CHAN_INFO_FREQUENCY] = "frequency",
    [IIO_CHAN_INFO_PHASE] = "phase",
    [IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
    [IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
};

const struct iio_chan_spec
*iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
{
    int i;

    for (i = 0; i < indio_dev->num_channels; i++)
        if (indio_dev->channels[i].scan_index == si)
            return &indio_dev->channels[i];
    return NULL;
}

/* This turns up an awful lot */
ssize_t iio_read_const_attr(struct device *dev,
                struct device_attribute *attr,
                char *buf)
{
    return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
}
EXPORT_SYMBOL(iio_read_const_attr);

static int __init iio_init(void)
{
    int ret;

    /* Register sysfs bus */
    ret  = bus_register(&iio_bus_type);
    if (ret < 0) {
        printk(KERN_ERR
               "%s could not register bus type\n",
            __FILE__);
        goto error_nothing;
    }

    ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
    if (ret < 0) {
        printk(KERN_ERR "%s: failed to allocate char dev region\n",
               __FILE__);
        goto error_unregister_bus_type;
    }

    iio_debugfs_dentry = debugfs_create_dir("iio", NULL);

    return 0;

error_unregister_bus_type:
    bus_unregister(&iio_bus_type);
error_nothing:
    return ret;
}

static void __exit iio_exit(void)
{
    if (iio_devt)
        unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
    bus_unregister(&iio_bus_type);
    debugfs_remove(iio_debugfs_dentry);
}

#if defined(CONFIG_DEBUG_FS)
static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
                  size_t count, loff_t *ppos)
{
    struct iio_dev *indio_dev = file->private_data;
    char buf[20];
    unsigned val = 0;
    ssize_t len;
    int ret;

    ret = indio_dev->info->debugfs_reg_access(indio_dev,
                          indio_dev->cached_reg_addr,
                          0, &val);
    if (ret)
        dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);

    len = snprintf(buf, sizeof(buf), "0x%X\n", val);

    return simple_read_from_buffer(userbuf, count, ppos, buf, len);
}

static ssize_t iio_debugfs_write_reg(struct file *file,
             const char __user *userbuf, size_t count, loff_t *ppos)
{
    struct iio_dev *indio_dev = file->private_data;
    unsigned reg, val;
    char buf[80];
    int ret;

    count = min_t(size_t, count, (sizeof(buf)-1));
    if (copy_from_user(buf, userbuf, count))
        return -EFAULT;

    buf[count] = 0;

    ret = sscanf(buf, "%i %i", &reg, &val);

    switch (ret) {
    case 1:
        indio_dev->cached_reg_addr = reg;
        break;
    case 2:
        indio_dev->cached_reg_addr = reg;
        ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
                              val, NULL);
        if (ret) {
            dev_err(indio_dev->dev.parent, "%s: write failed\n",
                __func__);
            return ret;
        }
        break;
    default:
        return -EINVAL;
    }

    return count;
}

static const struct file_operations iio_debugfs_reg_fops = {
    .open = simple_open,
    .read = iio_debugfs_read_reg,
    .write = iio_debugfs_write_reg,
};

static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
{
    debugfs_remove_recursive(indio_dev->debugfs_dentry);
}

static int iio_device_register_debugfs(struct iio_dev *indio_dev)
{
    struct dentry *d;

    if (indio_dev->info->debugfs_reg_access == NULL)
        return 0;

    if (!iio_debugfs_dentry)
        return 0;

    indio_dev->debugfs_dentry =
        debugfs_create_dir(dev_name(&indio_dev->dev),
                   iio_debugfs_dentry);
    if (indio_dev->debugfs_dentry == NULL) {
        dev_warn(indio_dev->dev.parent,
             "Failed to create debugfs directory\n");
        return -EFAULT;
    }

    d = debugfs_create_file("direct_reg_access", 0644,
                indio_dev->debugfs_dentry,
                indio_dev, &iio_debugfs_reg_fops);
    if (!d) {
        iio_device_unregister_debugfs(indio_dev);
        return -ENOMEM;
    }

    return 0;
}
#else
static int iio_device_register_debugfs(struct iio_dev *indio_dev)
{
    return 0;
}

static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
{
}
#endif /* CONFIG_DEBUG_FS */

static ssize_t iio_read_channel_ext_info(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
{
    struct iio_dev *indio_dev = dev_to_iio_dev(dev);
    struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
    const struct iio_chan_spec_ext_info *ext_info;

    ext_info = &this_attr->c->ext_info[this_attr->address];

    return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
}

static ssize_t iio_write_channel_ext_info(struct device *dev,
                     struct device_attribute *attr,
                     const char *buf,
                     size_t len)
{
    struct iio_dev *indio_dev = dev_to_iio_dev(dev);
    struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
    const struct iio_chan_spec_ext_info *ext_info;

    ext_info = &this_attr->c->ext_info[this_attr->address];

    return ext_info->write(indio_dev, ext_info->private,
                   this_attr->c, buf, len);
}

ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
    uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
{
    const struct iio_enum *e = (const struct iio_enum *)priv;
    unsigned int i;
    size_t len = 0;

    if (!e->num_items)
        return 0;

    for (i = 0; i < e->num_items; ++i)
        len += scnprintf(buf + len, PAGE_SIZE - len, "%s ", e->items[i]);

    /* replace last space with a newline */
    buf[len - 1] = '\n';

    return len;
}
EXPORT_SYMBOL_GPL(iio_enum_available_read);

ssize_t iio_enum_read(struct iio_dev *indio_dev,
    uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
{
    const struct iio_enum *e = (const struct iio_enum *)priv;
    int i;

    if (!e->get)
        return -EINVAL;

    i = e->get(indio_dev, chan);
    if (i < 0)
        return i;
    else if (i >= e->num_items)
        return -EINVAL;

    return sprintf(buf, "%s\n", e->items[i]);
}
EXPORT_SYMBOL_GPL(iio_enum_read);

ssize_t iio_enum_write(struct iio_dev *indio_dev,
    uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
    size_t len)
{
    const struct iio_enum *e = (const struct iio_enum *)priv;
    unsigned int i;
    int ret;

    if (!e->set)
        return -EINVAL;

    for (i = 0; i < e->num_items; i++) {
        if (sysfs_streq(buf, e->items[i]))
            break;
    }

    if (i == e->num_items)
        return -EINVAL;

    ret = e->set(indio_dev, chan, i);
    return ret ? ret : len;
}
EXPORT_SYMBOL_GPL(iio_enum_write);

static ssize_t iio_read_channel_info(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
{
    struct iio_dev *indio_dev = dev_to_iio_dev(dev);
    struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
    unsigned long long tmp;
    int val, val2;
    bool scale_db = false;
    int ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
                        &val, &val2, this_attr->address);

    if (ret < 0)
        return ret;

    switch (ret) {
    case IIO_VAL_INT:
        return sprintf(buf, "%d\n", val);
    case IIO_VAL_INT_PLUS_MICRO_DB:
        scale_db = true;
    case IIO_VAL_INT_PLUS_MICRO:
        if (val2 < 0)
            return sprintf(buf, "-%d.%06u%s\n", val, -val2,
                scale_db ? " dB" : "");
        else
            return sprintf(buf, "%d.%06u%s\n", val, val2,
                scale_db ? " dB" : "");
    case IIO_VAL_INT_PLUS_NANO:
        if (val2 < 0)
            return sprintf(buf, "-%d.%09u\n", val, -val2);
        else
            return sprintf(buf, "%d.%09u\n", val, val2);
    case IIO_VAL_FRACTIONAL:
        tmp = div_s64((s64)val * 1000000000LL, val2);
        val2 = do_div(tmp, 1000000000LL);
        val = tmp;
        return sprintf(buf, "%d.%09u\n", val, val2);
    default:
        return 0;
    }
}

static ssize_t iio_write_channel_info(struct device *dev,
                      struct device_attribute *attr,
                      const char *buf,
                      size_t len)
{
    struct iio_dev *indio_dev = dev_to_iio_dev(dev);
    struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
    int ret, integer = 0, fract = 0, fract_mult = 100000;
    bool integer_part = true, negative = false;

    /* Assumes decimal - precision based on number of digits */
    if (!indio_dev->info->write_raw)
        return -EINVAL;

    if (indio_dev->info->write_raw_get_fmt)
        switch (indio_dev->info->write_raw_get_fmt(indio_dev,
            this_attr->c, this_attr->address)) {
        case IIO_VAL_INT_PLUS_MICRO:
            fract_mult = 100000;
            break;
        case IIO_VAL_INT_PLUS_NANO:
            fract_mult = 100000000;
            break;
        default:
            return -EINVAL;
        }

    if (buf[0] == '-') {
        negative = true;
        buf++;
    }

    while (*buf) {
        if ('0' <= *buf && *buf <= '9') {
            if (integer_part)
                integer = integer*10 + *buf - '0';
            else {
                fract += fract_mult*(*buf - '0');
                if (fract_mult == 1)
                    break;
                fract_mult /= 10;
            }
        } else if (*buf == '\n') {
            if (*(buf + 1) == '\0')
                break;
            else
                return -EINVAL;
        } else if (*buf == '.') {
            integer_part = false;
        } else {
            return -EINVAL;
        }
        buf++;
    }
    if (negative) {
        if (integer)
            integer = -integer;
        else
            fract = -fract;
    }

    ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
                     integer, fract, this_attr->address);
    if (ret)
        return ret;

    return len;
}

static
int __iio_device_attr_init(struct device_attribute *dev_attr,
               const char *postfix,
               struct iio_chan_spec const *chan,
               ssize_t (*readfunc)(struct device *dev,
                           struct device_attribute *attr,
                           char *buf),
               ssize_t (*writefunc)(struct device *dev,
                        struct device_attribute *attr,
                        const char *buf,
                        size_t len),
               bool generic)
{
    int ret;
    char *name_format, *full_postfix;
    sysfs_attr_init(&dev_attr->attr);

    /* Build up postfix of <extend_name>_<modifier>_postfix */
    if (chan->modified && !generic) {
        if (chan->extend_name)
            full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
                         iio_modifier_names[chan
                                    ->channel2],
                         chan->extend_name,
                         postfix);
        else
            full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
                         iio_modifier_names[chan
                                    ->channel2],
                         postfix);
    } else {
        if (chan->extend_name == NULL)
            full_postfix = kstrdup(postfix, GFP_KERNEL);
        else
            full_postfix = kasprintf(GFP_KERNEL,
                         "%s_%s",
                         chan->extend_name,
                         postfix);
    }
    if (full_postfix == NULL) {
        ret = -ENOMEM;
        goto error_ret;
    }

    if (chan->differential) { /* Differential can not have modifier */
        if (generic)
            name_format
                = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
                        iio_direction[chan->output],
                        iio_chan_type_name_spec[chan->type],
                        iio_chan_type_name_spec[chan->type],
                        full_postfix);
        else if (chan->indexed)
            name_format
                = kasprintf(GFP_KERNEL, "%s_%s%d-%s%d_%s",
                        iio_direction[chan->output],
                        iio_chan_type_name_spec[chan->type],
                        chan->channel,
                        iio_chan_type_name_spec[chan->type],
                        chan->channel2,
                        full_postfix);
        else {
            WARN_ON("Differential channels must be indexed\n");
            ret = -EINVAL;
            goto error_free_full_postfix;
        }
    } else { /* Single ended */
        if (generic)
            name_format
                = kasprintf(GFP_KERNEL, "%s_%s_%s",
                        iio_direction[chan->output],
                        iio_chan_type_name_spec[chan->type],
                        full_postfix);
        else if (chan->indexed)
            name_format
                = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
                        iio_direction[chan->output],
                        iio_chan_type_name_spec[chan->type],
                        chan->channel,
                        full_postfix);
        else
            name_format
                = kasprintf(GFP_KERNEL, "%s_%s_%s",
                        iio_direction[chan->output],
                        iio_chan_type_name_spec[chan->type],
                        full_postfix);
    }
    if (name_format == NULL) {
        ret = -ENOMEM;
        goto error_free_full_postfix;
    }
    dev_attr->attr.name = kasprintf(GFP_KERNEL,
                    name_format,
                    chan->channel,
                    chan->channel2);
    if (dev_attr->attr.name == NULL) {
        ret = -ENOMEM;
        goto error_free_name_format;
    }

    if (readfunc) {
        dev_attr->attr.mode |= S_IRUGO;
        dev_attr->show = readfunc;
    }

    if (writefunc) {
        dev_attr->attr.mode |= S_IWUSR;
        dev_attr->store = writefunc;
    }
    kfree(name_format);
    kfree(full_postfix);

    return 0;

error_free_name_format:
    kfree(name_format);
error_free_full_postfix:
    kfree(full_postfix);
error_ret:
    return ret;
}

static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
{
    kfree(dev_attr->attr.name);
}

int __iio_add_chan_devattr(const char *postfix,
               struct iio_chan_spec const *chan,
               ssize_t (*readfunc)(struct device *dev,
                           struct device_attribute *attr,
                           char *buf),
               ssize_t (*writefunc)(struct device *dev,
                        struct device_attribute *attr,
                        const char *buf,
                        size_t len),
               u64 mask,
               bool generic,
               struct device *dev,
               struct list_head *attr_list)
{
    int ret;
    struct iio_dev_attr *iio_attr, *t;

    iio_attr = kzalloc(sizeof *iio_attr, GFP_KERNEL);
    if (iio_attr == NULL) {
        ret = -ENOMEM;
        goto error_ret;
    }
    ret = __iio_device_attr_init(&iio_attr->dev_attr,
                     postfix, chan,
                     readfunc, writefunc, generic);
    if (ret)
        goto error_iio_dev_attr_free;
    iio_attr->c = chan;
    iio_attr->address = mask;
    list_for_each_entry(t, attr_list, l)
        if (strcmp(t->dev_attr.attr.name,
               iio_attr->dev_attr.attr.name) == 0) {
            if (!generic)
                dev_err(dev, "tried to double register : %s\n",
                    t->dev_attr.attr.name);
            ret = -EBUSY;
            goto error_device_attr_deinit;
        }
    list_add(&iio_attr->l, attr_list);

    return 0;

error_device_attr_deinit:
    __iio_device_attr_deinit(&iio_attr->dev_attr);
error_iio_dev_attr_free:
    kfree(iio_attr);
error_ret:
    return ret;
}

static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
                    struct iio_chan_spec const *chan)
{
    int ret, attrcount = 0;
    int i;
    const struct iio_chan_spec_ext_info *ext_info;

    if (chan->channel < 0)
        return 0;
    for_each_set_bit(i, &chan->info_mask, sizeof(long)*8) {
        ret = __iio_add_chan_devattr(iio_chan_info_postfix[i/2],
                         chan,
                         &iio_read_channel_info,
                         &iio_write_channel_info,
                         i/2,
                         !(i%2),
                         &indio_dev->dev,
                         &indio_dev->channel_attr_list);
        if (ret == -EBUSY && (i%2 == 0)) {
            ret = 0;
            continue;
        }
        if (ret < 0)
            goto error_ret;
        attrcount++;
    }

    if (chan->ext_info) {
        unsigned int i = 0;
        for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
            ret = __iio_add_chan_devattr(ext_info->name,
                    chan,
                    ext_info->read ?
                        &iio_read_channel_ext_info : NULL,
                    ext_info->write ?
                        &iio_write_channel_ext_info : NULL,
                    i,
                    ext_info->shared,
                    &indio_dev->dev,
                    &indio_dev->channel_attr_list);
            i++;
            if (ret == -EBUSY && ext_info->shared)
                continue;

            if (ret)
                goto error_ret;

            attrcount++;
        }
    }

    ret = attrcount;
error_ret:
    return ret;
}

static void iio_device_remove_and_free_read_attr(struct iio_dev *indio_dev,
                         struct iio_dev_attr *p)
{
    kfree(p->dev_attr.attr.name);
    kfree(p);
}

static ssize_t iio_show_dev_name(struct device *dev,
                 struct device_attribute *attr,
                 char *buf)
{
    struct iio_dev *indio_dev = dev_to_iio_dev(dev);
    return sprintf(buf, "%s\n", indio_dev->name);
}

static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);

static int iio_device_register_sysfs(struct iio_dev *indio_dev)
{
    int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
    struct iio_dev_attr *p, *n;
    struct attribute **attr;

    /* First count elements in any existing group */
    if (indio_dev->info->attrs) {
        attr = indio_dev->info->attrs->attrs;
        while (*attr++ != NULL)
            attrcount_orig++;
    }
    attrcount = attrcount_orig;
    /*
     * New channel registration method - relies on the fact a group does
     * not need to be initialized if its name is NULL.
     */
    if (indio_dev->channels)
        for (i = 0; i < indio_dev->num_channels; i++) {
            ret = iio_device_add_channel_sysfs(indio_dev,
                               &indio_dev
                               ->channels[i]);
            if (ret < 0)
                goto error_clear_attrs;
            attrcount += ret;
        }

    if (indio_dev->name)
        attrcount++;

    indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
                           sizeof(indio_dev->chan_attr_group.attrs[0]),
                           GFP_KERNEL);
    if (indio_dev->chan_attr_group.attrs == NULL) {
        ret = -ENOMEM;
        goto error_clear_attrs;
    }
    /* Copy across original attributes */
    if (indio_dev->info->attrs)
        memcpy(indio_dev->chan_attr_group.attrs,
               indio_dev->info->attrs->attrs,
               sizeof(indio_dev->chan_attr_group.attrs[0])
               *attrcount_orig);
    attrn = attrcount_orig;
    /* Add all elements from the list. */
    list_for_each_entry(p, &indio_dev->channel_attr_list, l)
        indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
    if (indio_dev->name)
        indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;

    indio_dev->groups[indio_dev->groupcounter++] =
        &indio_dev->chan_attr_group;

    return 0;

error_clear_attrs:
    list_for_each_entry_safe(p, n,
                 &indio_dev->channel_attr_list, l) {
        list_del(&p->l);
        iio_device_remove_and_free_read_attr(indio_dev, p);
    }

    return ret;
}

static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
{

    struct iio_dev_attr *p, *n;

    list_for_each_entry_safe(p, n, &indio_dev->channel_attr_list, l) {
        list_del(&p->l);
        iio_device_remove_and_free_read_attr(indio_dev, p);
    }
    kfree(indio_dev->chan_attr_group.attrs);
}

static void iio_dev_release(struct device *device)
{
    struct iio_dev *indio_dev = dev_to_iio_dev(device);
    if (indio_dev->chrdev.dev)
        cdev_del(&indio_dev->chrdev);
    if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
        iio_device_unregister_trigger_consumer(indio_dev);
    iio_device_unregister_eventset(indio_dev);
    iio_device_unregister_sysfs(indio_dev);
    iio_device_unregister_debugfs(indio_dev);

    ida_simple_remove(&iio_ida, indio_dev->id);
    kfree(indio_dev);
}

static struct device_type iio_dev_type = {
    .name = "iio_device",
    .release = iio_dev_release,
};

struct iio_dev *iio_device_alloc(int sizeof_priv)
{
    struct iio_dev *dev;
    size_t alloc_size;

    alloc_size = sizeof(struct iio_dev);
    if (sizeof_priv) {
        alloc_size = ALIGN(alloc_size, IIO_ALIGN);
        alloc_size += sizeof_priv;
    }
    /* ensure 32-byte alignment of whole construct ? */
    alloc_size += IIO_ALIGN - 1;

    dev = kzalloc(alloc_size, GFP_KERNEL);

    if (dev) {
        dev->dev.groups = dev->groups;
        dev->dev.type = &iio_dev_type;
        dev->dev.bus = &iio_bus_type;
        device_initialize(&dev->dev);
        dev_set_drvdata(&dev->dev, (void *)dev);
        mutex_init(&dev->mlock);
        mutex_init(&dev->info_exist_lock);
        INIT_LIST_HEAD(&dev->channel_attr_list);

        dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
        if (dev->id < 0) {
            /* cannot use a dev_err as the name isn't available */
            printk(KERN_ERR "Failed to get id\n");
            kfree(dev);
            return NULL;
        }
        dev_set_name(&dev->dev, "iio:device%d", dev->id);
    }

    return dev;
}
EXPORT_SYMBOL(iio_device_alloc);

void iio_device_free(struct iio_dev *dev)
{
    if (dev)
        put_device(&dev->dev);
}
EXPORT_SYMBOL(iio_device_free);

static int iio_chrdev_open(struct inode *inode, struct file *filp)
{
    struct iio_dev *indio_dev = container_of(inode->i_cdev,
                        struct iio_dev, chrdev);

    if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
        return -EBUSY;

    filp->private_data = indio_dev;

    return 0;
}

static int iio_chrdev_release(struct inode *inode, struct file *filp)
{
    struct iio_dev *indio_dev = container_of(inode->i_cdev,
                        struct iio_dev, chrdev);
    clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
    return 0;
}

/* Somewhat of a cross file organization violation - ioctls here are actually
 * event related */
static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    struct iio_dev *indio_dev = filp->private_data;
    int __user *ip = (int __user *)arg;
    int fd;

    if (cmd == IIO_GET_EVENT_FD_IOCTL) {
        fd = iio_event_getfd(indio_dev);
        if (copy_to_user(ip, &fd, sizeof(fd)))
            return -EFAULT;
        return 0;
    }
    return -EINVAL;
}

static const struct file_operations iio_buffer_fileops = {
    .read = iio_buffer_read_first_n_outer_addr,
    .release = iio_chrdev_release,
    .open = iio_chrdev_open,
    .poll = iio_buffer_poll_addr,
    .owner = THIS_MODULE,
    .llseek = noop_llseek,
    .unlocked_ioctl = iio_ioctl,
    .compat_ioctl = iio_ioctl,
};

static const struct iio_buffer_setup_ops noop_ring_setup_ops;

int iio_device_register(struct iio_dev *indio_dev)
{
    int ret;

    /* configure elements for the chrdev */
    indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);

    ret = iio_device_register_debugfs(indio_dev);
    if (ret) {
        dev_err(indio_dev->dev.parent,
            "Failed to register debugfs interfaces\n");
        goto error_ret;
    }
    ret = iio_device_register_sysfs(indio_dev);
    if (ret) {
        dev_err(indio_dev->dev.parent,
            "Failed to register sysfs interfaces\n");
        goto error_unreg_debugfs;
    }
    ret = iio_device_register_eventset(indio_dev);
    if (ret) {
        dev_err(indio_dev->dev.parent,
            "Failed to register event set\n");
        goto error_free_sysfs;
    }
    if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
        iio_device_register_trigger_consumer(indio_dev);

    if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
        indio_dev->setup_ops == NULL)
        indio_dev->setup_ops = &noop_ring_setup_ops;

    ret = device_add(&indio_dev->dev);
    if (ret < 0)
        goto error_unreg_eventset;
    cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
    indio_dev->chrdev.owner = indio_dev->info->driver_module;
    ret = cdev_add(&indio_dev->chrdev, indio_dev->dev.devt, 1);
    if (ret < 0)
        goto error_del_device;
    return 0;

error_del_device:
    device_del(&indio_dev->dev);
error_unreg_eventset:
    iio_device_unregister_eventset(indio_dev);
error_free_sysfs:
    iio_device_unregister_sysfs(indio_dev);
error_unreg_debugfs:
    iio_device_unregister_debugfs(indio_dev);
error_ret:
    return ret;
}
EXPORT_SYMBOL(iio_device_register);

void iio_device_unregister(struct iio_dev *indio_dev)
{
    mutex_lock(&indio_dev->info_exist_lock);
    indio_dev->info = NULL;
    mutex_unlock(&indio_dev->info_exist_lock);
    device_del(&indio_dev->dev);
}
EXPORT_SYMBOL(iio_device_unregister);
subsys_initcall(iio_init);
module_exit(iio_exit);

MODULE_AUTHOR("Jonathan Cameron <[email protected]>");
MODULE_DESCRIPTION("Industrial I/O core");
MODULE_LICENSE("GPL");