/* rc-main.c - Remote Controller core module
 *
 * Copyright (C) 2009-2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 */

#include <media/rc-core.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/module.h>
#include "rc-core-priv.h"

/* Sizes are in bytes, 256 bytes allows for 32 entries on x64 */
#define IR_TAB_MIN_SIZE 256
#define IR_TAB_MAX_SIZE 8192

/* FIXME: IR_KEYPRESS_TIMEOUT should be protocol specific */
#define IR_KEYPRESS_TIMEOUT 250

/* Used to keep track of known keymaps */
static LIST_HEAD(rc_map_list);
static DEFINE_SPINLOCK(rc_map_lock);

static struct rc_map_list *seek_rc_map(const char *name)
{
        struct rc_map_list *map = NULL;

        spin_lock(&rc_map_lock);
        list_for_each_entry(map, &rc_map_list, list) {
                if (!strcmp(name, map->map.name)) {
                        spin_unlock(&rc_map_lock);
                        return map;
                }
        }
        spin_unlock(&rc_map_lock);

        return NULL;
}

struct rc_map *rc_map_get(const char *name)
{

        struct rc_map_list *map;

        map = seek_rc_map(name);
#ifdef MODULE
        if (!map) {
                int rc = request_module(name);
                if (rc < 0) {
                        printk(KERN_ERR "Couldn't load IR keymap %s\n", name);
                        return NULL;
                }
                msleep(20);     /* Give some time for IR to register */

                map = seek_rc_map(name);
        }
#endif
        if (!map) {
                printk(KERN_ERR "IR keymap %s not found\n", name);
                return NULL;
        }

        printk(KERN_INFO "Registered IR keymap %s\n", map->map.name);

        return &map->map;
}
EXPORT_SYMBOL_GPL(rc_map_get);

int rc_map_register(struct rc_map_list *map)
{
        spin_lock(&rc_map_lock);
        list_add_tail(&map->list, &rc_map_list);
        spin_unlock(&rc_map_lock);
        return 0;
}
EXPORT_SYMBOL_GPL(rc_map_register);

void rc_map_unregister(struct rc_map_list *map)
{
        spin_lock(&rc_map_lock);
        list_del(&map->list);
        spin_unlock(&rc_map_lock);
}
EXPORT_SYMBOL_GPL(rc_map_unregister);


static struct rc_map_table empty[] = {
        { 0x2a, KEY_COFFEE },
};

static struct rc_map_list empty_map = {
        .map = {
                .scan    = empty,
                .size    = ARRAY_SIZE(empty),
                .rc_type = RC_TYPE_UNKNOWN,     /* Legacy IR type */
                .name    = RC_MAP_EMPTY,
        }
};

/**
 * ir_create_table() - initializes a scancode table
 * @rc_map:     the rc_map to initialize
 * @name:       name to assign to the table
 * @rc_type:    ir type to assign to the new table
 * @size:       initial size of the table
 * @return:     zero on success or a negative error code
 *
 * This routine will initialize the rc_map and will allocate
 * memory to hold at least the specified number of elements.
 */
static int ir_create_table(struct rc_map *rc_map,
                           const char *name, u64 rc_type, size_t size)
{
        rc_map->name = name;
        rc_map->rc_type = rc_type;
        rc_map->alloc = roundup_pow_of_two(size * sizeof(struct rc_map_table));
        rc_map->size = rc_map->alloc / sizeof(struct rc_map_table);
        rc_map->scan = kmalloc(rc_map->alloc, GFP_KERNEL);
        if (!rc_map->scan)
                return -ENOMEM;

        IR_dprintk(1, "Allocated space for %u keycode entries (%u bytes)\n",
                   rc_map->size, rc_map->alloc);
        return 0;
}

/**
 * ir_free_table() - frees memory allocated by a scancode table
 * @rc_map:     the table whose mappings need to be freed
 *
 * This routine will free memory alloctaed for key mappings used by given
 * scancode table.
 */
static void ir_free_table(struct rc_map *rc_map)
{
        rc_map->size = 0;
        kfree(rc_map->scan);
        rc_map->scan = NULL;
}

/**
 * ir_resize_table() - resizes a scancode table if necessary
 * @rc_map:     the rc_map to resize
 * @gfp_flags:  gfp flags to use when allocating memory
 * @return:     zero on success or a negative error code
 *
 * This routine will shrink the rc_map if it has lots of
 * unused entries and grow it if it is full.
 */
static int ir_resize_table(struct rc_map *rc_map, gfp_t gfp_flags)
{
        unsigned int oldalloc = rc_map->alloc;
        unsigned int newalloc = oldalloc;
        struct rc_map_table *oldscan = rc_map->scan;
        struct rc_map_table *newscan;

        if (rc_map->size == rc_map->len) {
                /* All entries in use -> grow keytable */
                if (rc_map->alloc >= IR_TAB_MAX_SIZE)
                        return -ENOMEM;

                newalloc *= 2;
                IR_dprintk(1, "Growing table to %u bytes\n", newalloc);
        }

        if ((rc_map->len * 3 < rc_map->size) && (oldalloc > IR_TAB_MIN_SIZE)) {
                /* Less than 1/3 of entries in use -> shrink keytable */
                newalloc /= 2;
                IR_dprintk(1, "Shrinking table to %u bytes\n", newalloc);
        }

        if (newalloc == oldalloc)
                return 0;

        newscan = kmalloc(newalloc, gfp_flags);
        if (!newscan) {
                IR_dprintk(1, "Failed to kmalloc %u bytes\n", newalloc);
                return -ENOMEM;
        }

        memcpy(newscan, rc_map->scan, rc_map->len * sizeof(struct rc_map_table));
        rc_map->scan = newscan;
        rc_map->alloc = newalloc;
        rc_map->size = rc_map->alloc / sizeof(struct rc_map_table);
        kfree(oldscan);
        return 0;
}

/**
 * ir_update_mapping() - set a keycode in the scancode->keycode table
 * @dev:        the struct rc_dev device descriptor
 * @rc_map:     scancode table to be adjusted
 * @index:      index of the mapping that needs to be updated
 * @keycode:    the desired keycode
 * @return:     previous keycode assigned to the mapping
 *
 * This routine is used to update scancode->keycode mapping at given
 * position.
 */
static unsigned int ir_update_mapping(struct rc_dev *dev,
                                      struct rc_map *rc_map,
                                      unsigned int index,
                                      unsigned int new_keycode)
{
        int old_keycode = rc_map->scan[index].keycode;
        int i;

        /* Did the user wish to remove the mapping? */
        if (new_keycode == KEY_RESERVED || new_keycode == KEY_UNKNOWN) {
                IR_dprintk(1, "#%d: Deleting scan 0x%04x\n",
                           index, rc_map->scan[index].scancode);
                rc_map->len--;
                memmove(&rc_map->scan[index], &rc_map->scan[index+ 1],
                        (rc_map->len - index) * sizeof(struct rc_map_table));
        } else {
                IR_dprintk(1, "#%d: %s scan 0x%04x with key 0x%04x\n",
                           index,
                           old_keycode == KEY_RESERVED ? "New" : "Replacing",
                           rc_map->scan[index].scancode, new_keycode);
                rc_map->scan[index].keycode = new_keycode;
                __set_bit(new_keycode, dev->input_dev->keybit);
        }

        if (old_keycode != KEY_RESERVED) {
                /* A previous mapping was updated... */
                __clear_bit(old_keycode, dev->input_dev->keybit);
                /* ... but another scancode might use the same keycode */
                for (i = 0; i < rc_map->len; i++) {
                        if (rc_map->scan[i].keycode == old_keycode) {
                                __set_bit(old_keycode, dev->input_dev->keybit);
                                break;
                        }
                }

                /* Possibly shrink the keytable, failure is not a problem */
                ir_resize_table(rc_map, GFP_ATOMIC);
        }

        return old_keycode;
}

/**
 * ir_establish_scancode() - set a keycode in the scancode->keycode table
 * @dev:        the struct rc_dev device descriptor
 * @rc_map:     scancode table to be searched
 * @scancode:   the desired scancode
 * @resize:     controls whether we allowed to resize the table to
 *              accommodate not yet present scancodes
 * @return:     index of the mapping containing scancode in question
 *              or -1U in case of failure.
 *
 * This routine is used to locate given scancode in rc_map.
 * If scancode is not yet present the routine will allocate a new slot
 * for it.
 */
static unsigned int ir_establish_scancode(struct rc_dev *dev,
                                          struct rc_map *rc_map,
                                          unsigned int scancode,
                                          bool resize)
{
        unsigned int i;

        /*
         * Unfortunately, some hardware-based IR decoders don't provide
         * all bits for the complete IR code. In general, they provide only
         * the command part of the IR code. Yet, as it is possible to replace
         * the provided IR with another one, it is needed to allow loading
         * IR tables from other remotes. So, we support specifying a mask to
         * indicate the valid bits of the scancodes.
         */
        if (dev->scanmask)
                scancode &= dev->scanmask;

        /* First check if we already have a mapping for this ir command */
        for (i = 0; i < rc_map->len; i++) {
                if (rc_map->scan[i].scancode == scancode)
                        return i;

                /* Keytable is sorted from lowest to highest scancode */
                if (rc_map->scan[i].scancode >= scancode)
                        break;
        }

        /* No previous mapping found, we might need to grow the table */
        if (rc_map->size == rc_map->len) {
                if (!resize || ir_resize_table(rc_map, GFP_ATOMIC))
                        return -1U;
        }

        /* i is the proper index to insert our new keycode */
        if (i < rc_map->len)
                memmove(&rc_map->scan[i + 1], &rc_map->scan[i],
                        (rc_map->len - i) * sizeof(struct rc_map_table));
        rc_map->scan[i].scancode = scancode;
        rc_map->scan[i].keycode = KEY_RESERVED;
        rc_map->len++;

        return i;
}

/**
 * ir_setkeycode() - set a keycode in the scancode->keycode table
 * @idev:       the struct input_dev device descriptor
 * @scancode:   the desired scancode
 * @keycode:    result
 * @return:     -EINVAL if the keycode could not be inserted, otherwise zero.
 *
 * This routine is used to handle evdev EVIOCSKEY ioctl.
 */
static int ir_setkeycode(struct input_dev *idev,
                         const struct input_keymap_entry *ke,
                         unsigned int *old_keycode)
{
        struct rc_dev *rdev = input_get_drvdata(idev);
        struct rc_map *rc_map = &rdev->rc_map;
        unsigned int index;
        unsigned int scancode;
        int retval = 0;
        unsigned long flags;

        spin_lock_irqsave(&rc_map->lock, flags);

        if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
                index = ke->index;
                if (index >= rc_map->len) {
                        retval = -EINVAL;
                        goto out;
                }
        } else {
                retval = input_scancode_to_scalar(ke, &scancode);
                if (retval)
                        goto out;

                index = ir_establish_scancode(rdev, rc_map, scancode, true);
                if (index >= rc_map->len) {
                        retval = -ENOMEM;
                        goto out;
                }
        }

        *old_keycode = ir_update_mapping(rdev, rc_map, index, ke->keycode);

out:
        spin_unlock_irqrestore(&rc_map->lock, flags);
        return retval;
}

/**
 * ir_setkeytable() - sets several entries in the scancode->keycode table
 * @dev:        the struct rc_dev device descriptor
 * @to:         the struct rc_map to copy entries to
 * @from:       the struct rc_map to copy entries from
 * @return:     -ENOMEM if all keycodes could not be inserted, otherwise zero.
 *
 * This routine is used to handle table initialization.
 */
static int ir_setkeytable(struct rc_dev *dev,
                          const struct rc_map *from)
{
        struct rc_map *rc_map = &dev->rc_map;
        unsigned int i, index;
        int rc;

        rc = ir_create_table(rc_map, from->name,
                             from->rc_type, from->size);
        if (rc)
                return rc;

        IR_dprintk(1, "Allocated space for %u keycode entries (%u bytes)\n",
                   rc_map->size, rc_map->alloc);

        for (i = 0; i < from->size; i++) {
                index = ir_establish_scancode(dev, rc_map,
                                              from->scan[i].scancode, false);
                if (index >= rc_map->len) {
                        rc = -ENOMEM;
                        break;
                }

                ir_update_mapping(dev, rc_map, index,
                                  from->scan[i].keycode);
        }

        if (rc)
                ir_free_table(rc_map);

        return rc;
}

/**
 * ir_lookup_by_scancode() - locate mapping by scancode
 * @rc_map:     the struct rc_map to search
 * @scancode:   scancode to look for in the table
 * @return:     index in the table, -1U if not found
 *
 * This routine performs binary search in RC keykeymap table for
 * given scancode.
 */
static unsigned int ir_lookup_by_scancode(const struct rc_map *rc_map,
                                          unsigned int scancode)
{
        int start = 0;
        int end = rc_map->len - 1;
        int mid;

        while (start <= end) {
                mid = (start + end) / 2;
                if (rc_map->scan[mid].scancode < scancode)
                        start = mid + 1;
                else if (rc_map->scan[mid].scancode > scancode)
                        end = mid - 1;
                else
                        return mid;
        }

        return -1U;
}

/**
 * ir_getkeycode() - get a keycode from the scancode->keycode table
 * @idev:       the struct input_dev device descriptor
 * @scancode:   the desired scancode
 * @keycode:    used to return the keycode, if found, or KEY_RESERVED
 * @return:     always returns zero.
 *
 * This routine is used to handle evdev EVIOCGKEY ioctl.
 */
static int ir_getkeycode(struct input_dev *idev,
                         struct input_keymap_entry *ke)
{
        struct rc_dev *rdev = input_get_drvdata(idev);
        struct rc_map *rc_map = &rdev->rc_map;
        struct rc_map_table *entry;
        unsigned long flags;
        unsigned int index;
        unsigned int scancode;
        int retval;

        spin_lock_irqsave(&rc_map->lock, flags);

        if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
                index = ke->index;
        } else {
                retval = input_scancode_to_scalar(ke, &scancode);
                if (retval)
                        goto out;

                index = ir_lookup_by_scancode(rc_map, scancode);
        }

        if (index < rc_map->len) {
                entry = &rc_map->scan[index];

                ke->index = index;
                ke->keycode = entry->keycode;
                ke->len = sizeof(entry->scancode);
                memcpy(ke->scancode, &entry->scancode, sizeof(entry->scancode));

        } else if (!(ke->flags & INPUT_KEYMAP_BY_INDEX)) {
                /*
                 * We do not really know the valid range of scancodes
                 * so let's respond with KEY_RESERVED to anything we
                 * do not have mapping for [yet].
                 */
                ke->index = index;
                ke->keycode = KEY_RESERVED;
        } else {
                retval = -EINVAL;
                goto out;
        }

        retval = 0;

out:
        spin_unlock_irqrestore(&rc_map->lock, flags);
        return retval;
}

/**
 * rc_g_keycode_from_table() - gets the keycode that corresponds to a scancode
 * @dev:        the struct rc_dev descriptor of the device
 * @scancode:   the scancode to look for
 * @return:     the corresponding keycode, or KEY_RESERVED
 *
 * This routine is used by drivers which need to convert a scancode to a
 * keycode. Normally it should not be used since drivers should have no
 * interest in keycodes.
 */
u32 rc_g_keycode_from_table(struct rc_dev *dev, u32 scancode)
{
        struct rc_map *rc_map = &dev->rc_map;
        unsigned int keycode;
        unsigned int index;
        unsigned long flags;

        spin_lock_irqsave(&rc_map->lock, flags);

        index = ir_lookup_by_scancode(rc_map, scancode);
        keycode = index < rc_map->len ?
                        rc_map->scan[index].keycode : KEY_RESERVED;

        spin_unlock_irqrestore(&rc_map->lock, flags);

        if (keycode != KEY_RESERVED)
                IR_dprintk(1, "%s: scancode 0x%04x keycode 0x%02x\n",
                           dev->input_name, scancode, keycode);

        return keycode;
}
EXPORT_SYMBOL_GPL(rc_g_keycode_from_table);

/**
 * ir_do_keyup() - internal function to signal the release of a keypress
 * @dev:        the struct rc_dev descriptor of the device
 * @sync:       whether or not to call input_sync
 *
 * This function is used internally to release a keypress, it must be
 * called with keylock held.
 */
static void ir_do_keyup(struct rc_dev *dev, bool sync)
{
        if (!dev->keypressed)
                return;

        IR_dprintk(1, "keyup key 0x%04x\n", dev->last_keycode);
        input_report_key(dev->input_dev, dev->last_keycode, 0);
        if (sync)
                input_sync(dev->input_dev);
        dev->keypressed = false;
}

/**
 * rc_keyup() - signals the release of a keypress
 * @dev:        the struct rc_dev descriptor of the device
 *
 * This routine is used to signal that a key has been released on the
 * remote control.
 */
void rc_keyup(struct rc_dev *dev)
{
        unsigned long flags;

        spin_lock_irqsave(&dev->keylock, flags);
        ir_do_keyup(dev, true);
        spin_unlock_irqrestore(&dev->keylock, flags);
}
EXPORT_SYMBOL_GPL(rc_keyup);

/**
 * ir_timer_keyup() - generates a keyup event after a timeout
 * @cookie:     a pointer to the struct rc_dev for the device
 *
 * This routine will generate a keyup event some time after a keydown event
 * is generated when no further activity has been detected.
 */
static void ir_timer_keyup(unsigned long cookie)
{
        struct rc_dev *dev = (struct rc_dev *)cookie;
        unsigned long flags;

        /*
         * ir->keyup_jiffies is used to prevent a race condition if a
         * hardware interrupt occurs at this point and the keyup timer
         * event is moved further into the future as a result.
         *
         * The timer will then be reactivated and this function called
         * again in the future. We need to exit gracefully in that case
         * to allow the input subsystem to do its auto-repeat magic or
         * a keyup event might follow immediately after the keydown.
         */
        spin_lock_irqsave(&dev->keylock, flags);
        if (time_is_before_eq_jiffies(dev->keyup_jiffies))
                ir_do_keyup(dev, true);
        spin_unlock_irqrestore(&dev->keylock, flags);
}

/**
 * rc_repeat() - signals that a key is still pressed
 * @dev:        the struct rc_dev descriptor of the device
 *
 * This routine is used by IR decoders when a repeat message which does
 * not include the necessary bits to reproduce the scancode has been
 * received.
 */
void rc_repeat(struct rc_dev *dev)
{
        unsigned long flags;

        spin_lock_irqsave(&dev->keylock, flags);

        input_event(dev->input_dev, EV_MSC, MSC_SCAN, dev->last_scancode);
        input_sync(dev->input_dev);

        if (!dev->keypressed)
                goto out;

        dev->keyup_jiffies = jiffies + msecs_to_jiffies(IR_KEYPRESS_TIMEOUT);
        mod_timer(&dev->timer_keyup, dev->keyup_jiffies);

out:
        spin_unlock_irqrestore(&dev->keylock, flags);
}
EXPORT_SYMBOL_GPL(rc_repeat);

/**
 * ir_do_keydown() - internal function to process a keypress
 * @dev:        the struct rc_dev descriptor of the device
 * @scancode:   the scancode of the keypress
 * @keycode:    the keycode of the keypress
 * @toggle:     the toggle value of the keypress
 *
 * This function is used internally to register a keypress, it must be
 * called with keylock held.
 */
static void ir_do_keydown(struct rc_dev *dev, int scancode,
                          u32 keycode, u8 toggle)
{
        bool new_event = !dev->keypressed ||
                         dev->last_scancode != scancode ||
                         dev->last_toggle != toggle;

        if (new_event && dev->keypressed)
                ir_do_keyup(dev, false);

        input_event(dev->input_dev, EV_MSC, MSC_SCAN, scancode);

        if (new_event && keycode != KEY_RESERVED) {
                /* Register a keypress */
                dev->keypressed = true;
                dev->last_scancode = scancode;
                dev->last_toggle = toggle;
                dev->last_keycode = keycode;

                IR_dprintk(1, "%s: key down event, "
                           "key 0x%04x, scancode 0x%04x\n",
                           dev->input_name, keycode, scancode);
                input_report_key(dev->input_dev, keycode, 1);
        }

        input_sync(dev->input_dev);
}

/**
 * rc_keydown() - generates input event for a key press
 * @dev:        the struct rc_dev descriptor of the device
 * @scancode:   the scancode that we're seeking
 * @toggle:     the toggle value (protocol dependent, if the protocol doesn't
 *              support toggle values, this should be set to zero)
 *
 * This routine is used to signal that a key has been pressed on the
 * remote control.
 */
void rc_keydown(struct rc_dev *dev, int scancode, u8 toggle)
{
        unsigned long flags;
        u32 keycode = rc_g_keycode_from_table(dev, scancode);

        spin_lock_irqsave(&dev->keylock, flags);
        ir_do_keydown(dev, scancode, keycode, toggle);

        if (dev->keypressed) {
                dev->keyup_jiffies = jiffies + msecs_to_jiffies(IR_KEYPRESS_TIMEOUT);
                mod_timer(&dev->timer_keyup, dev->keyup_jiffies);
        }
        spin_unlock_irqrestore(&dev->keylock, flags);
}
EXPORT_SYMBOL_GPL(rc_keydown);

/**
 * rc_keydown_notimeout() - generates input event for a key press without
 *                          an automatic keyup event at a later time
 * @dev:        the struct rc_dev descriptor of the device
 * @scancode:   the scancode that we're seeking
 * @toggle:     the toggle value (protocol dependent, if the protocol doesn't
 *              support toggle values, this should be set to zero)
 *
 * This routine is used to signal that a key has been pressed on the
 * remote control. The driver must manually call rc_keyup() at a later stage.
 */
void rc_keydown_notimeout(struct rc_dev *dev, int scancode, u8 toggle)
{
        unsigned long flags;
        u32 keycode = rc_g_keycode_from_table(dev, scancode);

        spin_lock_irqsave(&dev->keylock, flags);
        ir_do_keydown(dev, scancode, keycode, toggle);
        spin_unlock_irqrestore(&dev->keylock, flags);
}
EXPORT_SYMBOL_GPL(rc_keydown_notimeout);

static int ir_open(struct input_dev *idev)
{
        struct rc_dev *rdev = input_get_drvdata(idev);

        return rdev->open(rdev);
}

static void ir_close(struct input_dev *idev)
{
        struct rc_dev *rdev = input_get_drvdata(idev);

         if (rdev)
                rdev->close(rdev);
}

/* class for /sys/class/rc */
static char *rc_devnode(struct device *dev, umode_t *mode)
{
        return kasprintf(GFP_KERNEL, "rc/%s", dev_name(dev));
}

static struct class rc_class = {
        .name           = "rc",
        .devnode        = rc_devnode,
};

/*
 * These are the protocol textual descriptions that are
 * used by the sysfs protocols file. Note that the order
 * of the entries is relevant.
 */
static struct {
        u64     type;
        char    *name;
} proto_names[] = {
        { RC_BIT_NONE,          "none"          },
        { RC_BIT_OTHER,         "other"         },
        { RC_BIT_UNKNOWN,       "unknown"       },
        { RC_BIT_RC5 |
          RC_BIT_RC5X,          "rc-5"          },
        { RC_BIT_NEC,           "nec"           },
        { RC_BIT_RC6_0 |
          RC_BIT_RC6_6A_20 |
          RC_BIT_RC6_6A_24 |
          RC_BIT_RC6_6A_32 |
          RC_BIT_RC6_MCE,       "rc-6"          },
        { RC_BIT_JVC,           "jvc"           },
        { RC_BIT_SONY12 |
          RC_BIT_SONY15 |
          RC_BIT_SONY20,        "sony"          },
        { RC_BIT_RC5_SZ,        "rc-5-sz"       },
        { RC_BIT_SANYO,         "sanyo"         },
        { RC_BIT_MCE_KBD,       "mce_kbd"       },
        { RC_BIT_LIRC,          "lirc"          },
};

/**
 * show_protocols() - shows the current IR protocol(s)
 * @device:     the device descriptor
 * @mattr:      the device attribute struct (unused)
 * @buf:        a pointer to the output buffer
 *
 * This routine is a callback routine for input read the IR protocol type(s).
 * it is trigged by reading /sys/class/rc/rc?/protocols.
 * It returns the protocol names of supported protocols.
 * Enabled protocols are printed in brackets.
 *
 * dev->lock is taken to guard against races between device
 * registration, store_protocols and show_protocols.
 */
static ssize_t show_protocols(struct device *device,
                              struct device_attribute *mattr, char *buf)
{
        struct rc_dev *dev = to_rc_dev(device);
        u64 allowed, enabled;
        char *tmp = buf;
        int i;

        /* Device is being removed */
        if (!dev)
                return -EINVAL;

        mutex_lock(&dev->lock);

        enabled = dev->enabled_protocols;
        if (dev->driver_type == RC_DRIVER_SCANCODE)
                allowed = dev->allowed_protos;
        else if (dev->raw)
                allowed = ir_raw_get_allowed_protocols();
        else {
                mutex_unlock(&dev->lock);
                return -ENODEV;
        }

        IR_dprintk(1, "allowed - 0x%llx, enabled - 0x%llx\n",
                   (long long)allowed,
                   (long long)enabled);

        for (i = 0; i < ARRAY_SIZE(proto_names); i++) {
                if (allowed & enabled & proto_names[i].type)
                        tmp += sprintf(tmp, "[%s] ", proto_names[i].name);
                else if (allowed & proto_names[i].type)
                        tmp += sprintf(tmp, "%s ", proto_names[i].name);

                if (allowed & proto_names[i].type)
                        allowed &= ~proto_names[i].type;
        }

        if (tmp != buf)
                tmp--;
        *tmp = '\n';

        mutex_unlock(&dev->lock);

        return tmp + 1 - buf;
}

/**
 * store_protocols() - changes the current IR protocol(s)
 * @device:     the device descriptor
 * @mattr:      the device attribute struct (unused)
 * @buf:        a pointer to the input buffer
 * @len:        length of the input buffer
 *
 * This routine is for changing the IR protocol type.
 * It is trigged by writing to /sys/class/rc/rc?/protocols.
 * Writing "+proto" will add a protocol to the list of enabled protocols.
 * Writing "-proto" will remove a protocol from the list of enabled protocols.
 * Writing "proto" will enable only "proto".
 * Writing "none" will disable all protocols.
 * Returns -EINVAL if an invalid protocol combination or unknown protocol name
 * is used, otherwise @len.
 *
 * dev->lock is taken to guard against races between device
 * registration, store_protocols and show_protocols.
 */
static ssize_t store_protocols(struct device *device,
                               struct device_attribute *mattr,
                               const char *data,
                               size_t len)
{
        struct rc_dev *dev = to_rc_dev(device);
        bool enable, disable;
        const char *tmp;
        u64 type;
        u64 mask;
        int rc, i, count = 0;
        ssize_t ret;

        /* Device is being removed */
        if (!dev)
                return -EINVAL;

        mutex_lock(&dev->lock);

        if (dev->driver_type != RC_DRIVER_SCANCODE && !dev->raw) {
                IR_dprintk(1, "Protocol switching not supported\n");
                ret = -EINVAL;
                goto out;
        }
        type = dev->enabled_protocols;

        while ((tmp = strsep((char **) &data, " \n")) != NULL) {
                if (!*tmp)
                        break;

                if (*tmp == '+') {
                        enable = true;
                        disable = false;
                        tmp++;
                } else if (*tmp == '-') {
                        enable = false;
                        disable = true;
                        tmp++;
                } else {
                        enable = false;
                        disable = false;
                }

                for (i = 0; i < ARRAY_SIZE(proto_names); i++) {
                        if (!strcasecmp(tmp, proto_names[i].name)) {
                                mask = proto_names[i].type;
                                break;
                        }
                }

                if (i == ARRAY_SIZE(proto_names)) {
                        IR_dprintk(1, "Unknown protocol: '%s'\n", tmp);
                        ret = -EINVAL;
                        goto out;
                }

                count++;

                if (enable)
                        type |= mask;
                else if (disable)
                        type &= ~mask;
                else
                        type = mask;
        }

        if (!count) {
                IR_dprintk(1, "Protocol not specified\n");
                ret = -EINVAL;
                goto out;
        }

        if (dev->change_protocol) {
                rc = dev->change_protocol(dev, &type);
                if (rc < 0) {
                        IR_dprintk(1, "Error setting protocols to 0x%llx\n",
                                   (long long)type);
                        ret = -EINVAL;
                        goto out;
                }
        }

        dev->enabled_protocols = type;
        IR_dprintk(1, "Current protocol(s): 0x%llx\n",
                   (long long)type);

        ret = len;

out:
        mutex_unlock(&dev->lock);
        return ret;
}

static void rc_dev_release(struct device *device)
{
}

#define ADD_HOTPLUG_VAR(fmt, val...)                                    \
        do {                                                            \
                int err = add_uevent_var(env, fmt, val);                \
                if (err)                                                \
                        return err;                                     \
        } while (0)

static int rc_dev_uevent(struct device *device, struct kobj_uevent_env *env)
{
        struct rc_dev *dev = to_rc_dev(device);

        if (!dev || !dev->input_dev)
                return -ENODEV;

        if (dev->rc_map.name)
                ADD_HOTPLUG_VAR("NAME=%s", dev->rc_map.name);
        if (dev->driver_name)
                ADD_HOTPLUG_VAR("DRV_NAME=%s", dev->driver_name);

        return 0;
}

/*
 * Static device attribute struct with the sysfs attributes for IR's
 */
static DEVICE_ATTR(protocols, S_IRUGO | S_IWUSR,
                   show_protocols, store_protocols);

static struct attribute *rc_dev_attrs[] = {
        &dev_attr_protocols.attr,
        NULL,
};

static struct attribute_group rc_dev_attr_grp = {
        .attrs  = rc_dev_attrs,
};

static const struct attribute_group *rc_dev_attr_groups[] = {
        &rc_dev_attr_grp,
        NULL
};

static struct device_type rc_dev_type = {
        .groups         = rc_dev_attr_groups,
        .release        = rc_dev_release,
        .uevent         = rc_dev_uevent,
};

struct rc_dev *rc_allocate_device(void)
{
        struct rc_dev *dev;

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (!dev)
                return NULL;

        dev->input_dev = input_allocate_device();
        if (!dev->input_dev) {
                kfree(dev);
                return NULL;
        }

        dev->input_dev->getkeycode = ir_getkeycode;
        dev->input_dev->setkeycode = ir_setkeycode;
        input_set_drvdata(dev->input_dev, dev);

        spin_lock_init(&dev->rc_map.lock);
        spin_lock_init(&dev->keylock);
        mutex_init(&dev->lock);
        setup_timer(&dev->timer_keyup, ir_timer_keyup, (unsigned long)dev);

        dev->dev.type = &rc_dev_type;
        dev->dev.class = &rc_class;
        device_initialize(&dev->dev);

        __module_get(THIS_MODULE);
        return dev;
}
EXPORT_SYMBOL_GPL(rc_allocate_device);

void rc_free_device(struct rc_dev *dev)
{
        if (!dev)
                return;

        if (dev->input_dev)
                input_free_device(dev->input_dev);

        put_device(&dev->dev);

        kfree(dev);
        module_put(THIS_MODULE);
}
EXPORT_SYMBOL_GPL(rc_free_device);

int rc_register_device(struct rc_dev *dev)
{
        static bool raw_init = false; /* raw decoders loaded? */
        static atomic_t devno = ATOMIC_INIT(0);
        struct rc_map *rc_map;
        const char *path;
        int rc;

        if (!dev || !dev->map_name)
                return -EINVAL;

        rc_map = rc_map_get(dev->map_name);
        if (!rc_map)
                rc_map = rc_map_get(RC_MAP_EMPTY);
        if (!rc_map || !rc_map->scan || rc_map->size == 0)
                return -EINVAL;

        set_bit(EV_KEY, dev->input_dev->evbit);
        set_bit(EV_REP, dev->input_dev->evbit);
        set_bit(EV_MSC, dev->input_dev->evbit);
        set_bit(MSC_SCAN, dev->input_dev->mscbit);
        if (dev->open)
                dev->input_dev->open = ir_open;
        if (dev->close)
                dev->input_dev->close = ir_close;

        /*
         * Take the lock here, as the device sysfs node will appear
         * when device_add() is called, which may trigger an ir-keytable udev
         * rule, which will in turn call show_protocols and access
         * dev->enabled_protocols before it has been initialized.
         */
        mutex_lock(&dev->lock);

        dev->devno = (unsigned long)(atomic_inc_return(&devno) - 1);
        dev_set_name(&dev->dev, "rc%ld", dev->devno);
        dev_set_drvdata(&dev->dev, dev);
        rc = device_add(&dev->dev);
        if (rc)
                goto out_unlock;

        rc = ir_setkeytable(dev, rc_map);
        if (rc)
                goto out_dev;

        dev->input_dev->dev.parent = &dev->dev;
        memcpy(&dev->input_dev->id, &dev->input_id, sizeof(dev->input_id));
        dev->input_dev->phys = dev->input_phys;
        dev->input_dev->name = dev->input_name;
        rc = input_register_device(dev->input_dev);
        if (rc)
                goto out_table;

        /*
         * Default delay of 250ms is too short for some protocols, especially
         * since the timeout is currently set to 250ms. Increase it to 500ms,
         * to avoid wrong repetition of the keycodes. Note that this must be
         * set after the call to input_register_device().
         */
        dev->input_dev->rep[REP_DELAY] = 500;

        /*
         * As a repeat event on protocols like RC-5 and NEC take as long as
         * 110/114ms, using 33ms as a repeat period is not the right thing
         * to do.
         */
        dev->input_dev->rep[REP_PERIOD] = 125;

        path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
        printk(KERN_INFO "%s: %s as %s\n",
                dev_name(&dev->dev),
                dev->input_name ? dev->input_name : "Unspecified device",
                path ? path : "N/A");
        kfree(path);

        if (dev->driver_type == RC_DRIVER_IR_RAW) {
                /* Load raw decoders, if they aren't already */
                if (!raw_init) {
                        IR_dprintk(1, "Loading raw decoders\n");
                        ir_raw_init();
                        raw_init = true;
                }
                rc = ir_raw_event_register(dev);
                if (rc < 0)
                        goto out_input;
        }

        if (dev->change_protocol) {
                u64 rc_type = (1 << rc_map->rc_type);
                rc = dev->change_protocol(dev, &rc_type);
                if (rc < 0)
                        goto out_raw;
                dev->enabled_protocols = rc_type;
        }

        mutex_unlock(&dev->lock);

        IR_dprintk(1, "Registered rc%ld (driver: %s, remote: %s, mode %s)\n",
                   dev->devno,
                   dev->driver_name ? dev->driver_name : "unknown",
                   rc_map->name ? rc_map->name : "unknown",
                   dev->driver_type == RC_DRIVER_IR_RAW ? "raw" : "cooked");

        return 0;

out_raw:
        if (dev->driver_type == RC_DRIVER_IR_RAW)
                ir_raw_event_unregister(dev);
out_input:
        input_unregister_device(dev->input_dev);
        dev->input_dev = NULL;
out_table:
        ir_free_table(&dev->rc_map);
out_dev:
        device_del(&dev->dev);
out_unlock:
        mutex_unlock(&dev->lock);
        return rc;
}
EXPORT_SYMBOL_GPL(rc_register_device);

void rc_unregister_device(struct rc_dev *dev)
{
        if (!dev)
                return;

        del_timer_sync(&dev->timer_keyup);

        if (dev->driver_type == RC_DRIVER_IR_RAW)
                ir_raw_event_unregister(dev);

        /* Freeing the table should also call the stop callback */
        ir_free_table(&dev->rc_map);
        IR_dprintk(1, "Freed keycode table\n");

        input_unregister_device(dev->input_dev);
        dev->input_dev = NULL;

        device_del(&dev->dev);

        rc_free_device(dev);
}

EXPORT_SYMBOL_GPL(rc_unregister_device);

/*
 * Init/exit code for the module. Basically, creates/removes /sys/class/rc
 */

static int __init rc_core_init(void)
{
        int rc = class_register(&rc_class);
        if (rc) {
                printk(KERN_ERR "rc_core: unable to register rc class\n");
                return rc;
        }

        rc_map_register(&empty_map);

        return 0;
}

static void __exit rc_core_exit(void)
{
        class_unregister(&rc_class);
        rc_map_unregister(&empty_map);
}

subsys_initcall(rc_core_init);
module_exit(rc_core_exit);

int rc_core_debug;    /* ir_debug level (0,1,2) */
EXPORT_SYMBOL_GPL(rc_core_debug);
module_param_named(debug, rc_core_debug, int, 0644);

MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
MODULE_LICENSE("GPL");