/* The industrial I/O core in kernel channel mapping
 *
 * Copyright (c) 2011 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.
 */
#include <linux/err.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/of.h>

#include <linux/iio/iio.h>
#include "iio_core.h"
#include <linux/iio/machine.h>
#include <linux/iio/driver.h>
#include <linux/iio/consumer.h>

struct iio_map_internal {
        struct iio_dev *indio_dev;
        struct iio_map *map;
        struct list_head l;
};

static LIST_HEAD(iio_map_list);
static DEFINE_MUTEX(iio_map_list_lock);

int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
{
        int i = 0, ret = 0;
        struct iio_map_internal *mapi;

        if (maps == NULL)
                return 0;

        mutex_lock(&iio_map_list_lock);
        while (maps[i].consumer_dev_name != NULL) {
                mapi = kzalloc(sizeof(*mapi), GFP_KERNEL);
                if (mapi == NULL) {
                        ret = -ENOMEM;
                        goto error_ret;
                }
                mapi->map = &maps[i];
                mapi->indio_dev = indio_dev;
                list_add(&mapi->l, &iio_map_list);
                i++;
        }
error_ret:
        mutex_unlock(&iio_map_list_lock);

        return ret;
}
EXPORT_SYMBOL_GPL(iio_map_array_register);


/*
 * Remove all map entries associated with the given iio device
 */
int iio_map_array_unregister(struct iio_dev *indio_dev)
{
        int ret = -ENODEV;
        struct iio_map_internal *mapi;
        struct list_head *pos, *tmp;

        mutex_lock(&iio_map_list_lock);
        list_for_each_safe(pos, tmp, &iio_map_list) {
                mapi = list_entry(pos, struct iio_map_internal, l);
                if (indio_dev == mapi->indio_dev) {
                        list_del(&mapi->l);
                        kfree(mapi);
                        ret = 0;
                }
        }
        mutex_unlock(&iio_map_list_lock);
        return ret;
}
EXPORT_SYMBOL_GPL(iio_map_array_unregister);

static const struct iio_chan_spec
*iio_chan_spec_from_name(const struct iio_dev *indio_dev, const char *name)
{
        int i;
        const struct iio_chan_spec *chan = NULL;

        for (i = 0; i < indio_dev->num_channels; i++)
                if (indio_dev->channels[i].datasheet_name &&
                    strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
                        chan = &indio_dev->channels[i];
                        break;
                }
        return chan;
}

#ifdef CONFIG_OF

static int iio_dev_node_match(struct device *dev, void *data)
{
        return dev->of_node == data && dev->type == &iio_device_type;
}

static int __of_iio_channel_get(struct iio_channel *channel,
                                struct device_node *np, int index)
{
        struct device *idev;
        struct iio_dev *indio_dev;
        int err;
        struct of_phandle_args iiospec;

        err = of_parse_phandle_with_args(np, "io-channels",
                                         "#io-channel-cells",
                                         index, &iiospec);
        if (err)
                return err;

        idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
                               iio_dev_node_match);
        of_node_put(iiospec.np);
        if (idev == NULL)
                return -EPROBE_DEFER;

        indio_dev = dev_to_iio_dev(idev);
        channel->indio_dev = indio_dev;
        index = iiospec.args_count ? iiospec.args[0] : 0;
        if (index >= indio_dev->num_channels) {
                err = -EINVAL;
                goto err_put;
        }
        channel->channel = &indio_dev->channels[index];

        return 0;

err_put:
        iio_device_put(indio_dev);
        return err;
}

static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
{
        struct iio_channel *channel;
        int err;

        if (index < 0)
                return ERR_PTR(-EINVAL);

        channel = kzalloc(sizeof(*channel), GFP_KERNEL);
        if (channel == NULL)
                return ERR_PTR(-ENOMEM);

        err = __of_iio_channel_get(channel, np, index);
        if (err)
                goto err_free_channel;

        return channel;

err_free_channel:
        kfree(channel);
        return ERR_PTR(err);
}

static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
                                                      const char *name)
{
        struct iio_channel *chan = NULL;

        /* Walk up the tree of devices looking for a matching iio channel */
        while (np) {
                int index = 0;

                /*
                 * For named iio channels, first look up the name in the
                 * "io-channel-names" property.  If it cannot be found, the
                 * index will be an error code, and of_iio_channel_get()
                 * will fail.
                 */
                if (name)
                        index = of_property_match_string(np, "io-channel-names",
                                                         name);
                chan = of_iio_channel_get(np, index);
                if (!IS_ERR(chan))
                        break;
                else if (name && index >= 0) {
                        pr_err("ERROR: could not get IIO channel %s:%s(%i)\n",
                                np->full_name, name ? name : "", index);
                        return chan;
                }

                /*
                 * No matching IIO channel found on this node.
                 * If the parent node has a "io-channel-ranges" property,
                 * then we can try one of its channels.
                 */
                np = np->parent;
                if (np && !of_get_property(np, "io-channel-ranges", NULL))
                        break;
        }
        return chan;
}

static struct iio_channel *of_iio_channel_get_all(struct device *dev)
{
        struct iio_channel *chans;
        int i, mapind, nummaps = 0;
        int ret;

        do {
                ret = of_parse_phandle_with_args(dev->of_node,
                                                 "io-channels",
                                                 "#io-channel-cells",
                                                 nummaps, NULL);
                if (ret < 0)
                        break;
        } while (++nummaps);

        if (nummaps == 0)       /* no error, return NULL to search map table */
                return NULL;

        /* NULL terminated array to save passing size */
        chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
        if (chans == NULL)
                return ERR_PTR(-ENOMEM);

        /* Search for OF matches */
        for (mapind = 0; mapind < nummaps; mapind++) {
                ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
                                           mapind);
                if (ret)
                        goto error_free_chans;
        }
        return chans;

error_free_chans:
        for (i = 0; i < mapind; i++)
                iio_device_put(chans[i].indio_dev);
        kfree(chans);
        return ERR_PTR(ret);
}

#else /* CONFIG_OF */

static inline struct iio_channel *
of_iio_channel_get_by_name(struct device_node *np, const char *name)
{
        return NULL;
}

static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
{
        return NULL;
}

#endif /* CONFIG_OF */

static struct iio_channel *iio_channel_get_sys(const char *name,
                                               const char *channel_name)
{
        struct iio_map_internal *c_i = NULL, *c = NULL;
        struct iio_channel *channel;
        int err;

        if (name == NULL && channel_name == NULL)
                return ERR_PTR(-ENODEV);

        /* first find matching entry the channel map */
        mutex_lock(&iio_map_list_lock);
        list_for_each_entry(c_i, &iio_map_list, l) {
                if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
                    (channel_name &&
                     strcmp(channel_name, c_i->map->consumer_channel) != 0))
                        continue;
                c = c_i;
                iio_device_get(c->indio_dev);
                break;
        }
        mutex_unlock(&iio_map_list_lock);
        if (c == NULL)
                return ERR_PTR(-ENODEV);

        channel = kzalloc(sizeof(*channel), GFP_KERNEL);
        if (channel == NULL) {
                err = -ENOMEM;
                goto error_no_mem;
        }

        channel->indio_dev = c->indio_dev;

        if (c->map->adc_channel_label) {
                channel->channel =
                        iio_chan_spec_from_name(channel->indio_dev,
                                                c->map->adc_channel_label);

                if (channel->channel == NULL) {
                        err = -EINVAL;
                        goto error_no_chan;
                }
        }

        return channel;

error_no_chan:
        kfree(channel);
error_no_mem:
        iio_device_put(c->indio_dev);
        return ERR_PTR(err);
}

struct iio_channel *iio_channel_get(struct device *dev,
                                    const char *channel_name)
{
        const char *name = dev ? dev_name(dev) : NULL;
        struct iio_channel *channel;

        if (dev) {
                channel = of_iio_channel_get_by_name(dev->of_node,
                                                     channel_name);
                if (channel != NULL)
                        return channel;
        }
        return iio_channel_get_sys(name, channel_name);
}
EXPORT_SYMBOL_GPL(iio_channel_get);

void iio_channel_release(struct iio_channel *channel)
{
        iio_device_put(channel->indio_dev);
        kfree(channel);
}
EXPORT_SYMBOL_GPL(iio_channel_release);

struct iio_channel *iio_channel_get_all(struct device *dev)
{
        const char *name;
        struct iio_channel *chans;
        struct iio_map_internal *c = NULL;
        int nummaps = 0;
        int mapind = 0;
        int i, ret;

        if (dev == NULL)
                return ERR_PTR(-EINVAL);

        chans = of_iio_channel_get_all(dev);
        if (chans)
                return chans;

        name = dev_name(dev);

        mutex_lock(&iio_map_list_lock);
        /* first count the matching maps */
        list_for_each_entry(c, &iio_map_list, l)
                if (name && strcmp(name, c->map->consumer_dev_name) != 0)
                        continue;
                else
                        nummaps++;

        if (nummaps == 0) {
                ret = -ENODEV;
                goto error_ret;
        }

        /* NULL terminated array to save passing size */
        chans = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL);
        if (chans == NULL) {
                ret = -ENOMEM;
                goto error_ret;
        }

        /* for each map fill in the chans element */
        list_for_each_entry(c, &iio_map_list, l) {
                if (name && strcmp(name, c->map->consumer_dev_name) != 0)
                        continue;
                chans[mapind].indio_dev = c->indio_dev;
                chans[mapind].data = c->map->consumer_data;
                chans[mapind].channel =
                        iio_chan_spec_from_name(chans[mapind].indio_dev,
                                                c->map->adc_channel_label);
                if (chans[mapind].channel == NULL) {
                        ret = -EINVAL;
                        goto error_free_chans;
                }
                iio_device_get(chans[mapind].indio_dev);
                mapind++;
        }
        if (mapind == 0) {
                ret = -ENODEV;
                goto error_free_chans;
        }
        mutex_unlock(&iio_map_list_lock);

        return chans;

error_free_chans:
        for (i = 0; i < nummaps; i++)
                iio_device_put(chans[i].indio_dev);
        kfree(chans);
error_ret:
        mutex_unlock(&iio_map_list_lock);

        return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(iio_channel_get_all);

void iio_channel_release_all(struct iio_channel *channels)
{
        struct iio_channel *chan = &channels[0];

        while (chan->indio_dev) {
                iio_device_put(chan->indio_dev);
                chan++;
        }
        kfree(channels);
}
EXPORT_SYMBOL_GPL(iio_channel_release_all);

static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
        enum iio_chan_info_enum info)
{
        int unused;

        if (val2 == NULL)
                val2 = &unused;

        return chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
                                                val, val2, info);
}

int iio_read_channel_raw(struct iio_channel *chan, int *val)
{
        int ret;

        mutex_lock(&chan->indio_dev->info_exist_lock);
        if (chan->indio_dev->info == NULL) {
                ret = -ENODEV;
                goto err_unlock;
        }

        ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
err_unlock:
        mutex_unlock(&chan->indio_dev->info_exist_lock);

        return ret;
}
EXPORT_SYMBOL_GPL(iio_read_channel_raw);

static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
        int raw, int *processed, unsigned int scale)
{
        int scale_type, scale_val, scale_val2, offset;
        s64 raw64 = raw;
        int ret;

        ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
        if (ret >= 0)
                raw64 += offset;

        scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
                                        IIO_CHAN_INFO_SCALE);
        if (scale_type < 0)
                return scale_type;

        switch (scale_type) {
        case IIO_VAL_INT:
                *processed = raw64 * scale_val;
                break;
        case IIO_VAL_INT_PLUS_MICRO:
                if (scale_val2 < 0)
                        *processed = -raw64 * scale_val;
                else
                        *processed = raw64 * scale_val;
                *processed += div_s64(raw64 * (s64)scale_val2 * scale,
                                      1000000LL);
                break;
        case IIO_VAL_INT_PLUS_NANO:
                if (scale_val2 < 0)
                        *processed = -raw64 * scale_val;
                else
                        *processed = raw64 * scale_val;
                *processed += div_s64(raw64 * (s64)scale_val2 * scale,
                                      1000000000LL);
                break;
        case IIO_VAL_FRACTIONAL:
                *processed = div_s64(raw64 * (s64)scale_val * scale,
                                     scale_val2);
                break;
        case IIO_VAL_FRACTIONAL_LOG2:
                *processed = (raw64 * (s64)scale_val * scale) >> scale_val2;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
        int *processed, unsigned int scale)
{
        int ret;

        mutex_lock(&chan->indio_dev->info_exist_lock);
        if (chan->indio_dev->info == NULL) {
                ret = -ENODEV;
                goto err_unlock;
        }

        ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
                                                        scale);
err_unlock:
        mutex_unlock(&chan->indio_dev->info_exist_lock);

        return ret;
}
EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);

int iio_read_channel_processed(struct iio_channel *chan, int *val)
{
        int ret;

        mutex_lock(&chan->indio_dev->info_exist_lock);
        if (chan->indio_dev->info == NULL) {
                ret = -ENODEV;
                goto err_unlock;
        }

        if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
                ret = iio_channel_read(chan, val, NULL,
                                       IIO_CHAN_INFO_PROCESSED);
        } else {
                ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
                if (ret < 0)
                        goto err_unlock;
                ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
        }

err_unlock:
        mutex_unlock(&chan->indio_dev->info_exist_lock);

        return ret;
}
EXPORT_SYMBOL_GPL(iio_read_channel_processed);

int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
{
        int ret;

        mutex_lock(&chan->indio_dev->info_exist_lock);
        if (chan->indio_dev->info == NULL) {
                ret = -ENODEV;
                goto err_unlock;
        }

        ret = iio_channel_read(chan, val, val2, IIO_CHAN_INFO_SCALE);
err_unlock:
        mutex_unlock(&chan->indio_dev->info_exist_lock);

        return ret;
}
EXPORT_SYMBOL_GPL(iio_read_channel_scale);

int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
{
        int ret = 0;
        /* Need to verify underlying driver has not gone away */

        mutex_lock(&chan->indio_dev->info_exist_lock);
        if (chan->indio_dev->info == NULL) {
                ret = -ENODEV;
                goto err_unlock;
        }

        *type = chan->channel->type;
err_unlock:
        mutex_unlock(&chan->indio_dev->info_exist_lock);

        return ret;
}
EXPORT_SYMBOL_GPL(iio_get_channel_type);