// SPDX-License-Identifier: GPL-2.0-only
/*
 * HID driver for the apple ir device
 *
 * Original driver written by James McKenzie
 * Ported to recent 2.6 kernel versions by Greg Kroah-Hartman <gregkh@suse.de>
 * Updated to support newer remotes by Bastien Nocera <hadess@hadess.net>
 * Ported to HID subsystem by Benjamin Tissoires <benjamin.tissoires@gmail.com>
 *
 * Copyright (C) 2006 James McKenzie
 * Copyright (C) 2008 Greg Kroah-Hartman <greg@kroah.com>
 * Copyright (C) 2008 Novell Inc.
 * Copyright (C) 2010, 2012 Bastien Nocera <hadess@hadess.net>
 * Copyright (C) 2013 Benjamin Tissoires <benjamin.tissoires@gmail.com>
 * Copyright (C) 2013 Red Hat Inc. All Rights Reserved
 */

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/module.h>
#include "hid-ids.h"

MODULE_AUTHOR("James McKenzie");
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
MODULE_DESCRIPTION("HID Apple IR remote controls");
MODULE_LICENSE("GPL");

#define KEY_MASK                0x0F
#define TWO_PACKETS_MASK        0x40

/*
 * James McKenzie has two devices both of which report the following
 * 25 87 ee 83 0a       +
 * 25 87 ee 83 0c       -
 * 25 87 ee 83 09       <<
 * 25 87 ee 83 06       >>
 * 25 87 ee 83 05       >"
 * 25 87 ee 83 03       menu
 * 26 00 00 00 00       for key repeat
 */

/*
 * Thomas Glanzmann reports the following responses
 * 25 87 ee ca 0b       +
 * 25 87 ee ca 0d       -
 * 25 87 ee ca 08       <<
 * 25 87 ee ca 07       >>
 * 25 87 ee ca 04       >"
 * 25 87 ee ca 02       menu
 * 26 00 00 00 00       for key repeat
 *
 * He also observes the following event sometimes
 * sent after a key is release, which I interpret
 * as a flat battery message
 * 25 87 e0 ca 06       flat battery
 */

/*
 * Alexandre Karpenko reports the following responses for Device ID 0x8242
 * 25 87 ee 47 0b       +
 * 25 87 ee 47 0d       -
 * 25 87 ee 47 08       <<
 * 25 87 ee 47 07       >>
 * 25 87 ee 47 04       >"
 * 25 87 ee 47 02       menu
 * 26 87 ee 47 **       for key repeat (** is the code of the key being held)
 */

/*
 * Bastien Nocera's remote
 * 25 87 ee 91 5f       followed by
 * 25 87 ee 91 05       gives you >"
 *
 * 25 87 ee 91 5c       followed by
 * 25 87 ee 91 05       gives you the middle button
 */

/*
 * Fabien Andre's remote
 * 25 87 ee a3 5e       followed by
 * 25 87 ee a3 04       gives you >"
 *
 * 25 87 ee a3 5d       followed by
 * 25 87 ee a3 04       gives you the middle button
 */

static const unsigned short appleir_key_table[] = {
        KEY_RESERVED,
        KEY_MENU,
        KEY_PLAYPAUSE,
        KEY_FORWARD,
        KEY_BACK,
        KEY_VOLUMEUP,
        KEY_VOLUMEDOWN,
        KEY_RESERVED,
        KEY_RESERVED,
        KEY_RESERVED,
        KEY_RESERVED,
        KEY_RESERVED,
        KEY_RESERVED,
        KEY_RESERVED,
        KEY_ENTER,
        KEY_PLAYPAUSE,
        KEY_RESERVED,
};

struct appleir {
        struct input_dev *input_dev;
        struct hid_device *hid;
        unsigned short keymap[ARRAY_SIZE(appleir_key_table)];
        struct timer_list key_up_timer; /* timer for key up */
        spinlock_t lock;                /* protects .current_key */
        int current_key;                /* the currently pressed key */
        int prev_key_idx;               /* key index in a 2 packets message */
};

static int get_key(int data)
{
        /*
         * The key is coded accross bits 2..9:
         *
         * 0x00 or 0x01 (        )      key:  0         -> KEY_RESERVED
         * 0x02 or 0x03 (  menu  )      key:  1         -> KEY_MENU
         * 0x04 or 0x05 (   >"   )      key:  2         -> KEY_PLAYPAUSE
         * 0x06 or 0x07 (   >>   )      key:  3         -> KEY_FORWARD
         * 0x08 or 0x09 (   <<   )      key:  4         -> KEY_BACK
         * 0x0a or 0x0b (    +   )      key:  5         -> KEY_VOLUMEUP
         * 0x0c or 0x0d (    -   )      key:  6         -> KEY_VOLUMEDOWN
         * 0x0e or 0x0f (        )      key:  7         -> KEY_RESERVED
         * 0x50 or 0x51 (        )      key:  8         -> KEY_RESERVED
         * 0x52 or 0x53 (        )      key:  9         -> KEY_RESERVED
         * 0x54 or 0x55 (        )      key: 10         -> KEY_RESERVED
         * 0x56 or 0x57 (        )      key: 11         -> KEY_RESERVED
         * 0x58 or 0x59 (        )      key: 12         -> KEY_RESERVED
         * 0x5a or 0x5b (        )      key: 13         -> KEY_RESERVED
         * 0x5c or 0x5d ( middle )      key: 14         -> KEY_ENTER
         * 0x5e or 0x5f (   >"   )      key: 15         -> KEY_PLAYPAUSE
         *
         * Packets starting with 0x5 are part of a two-packets message,
         * we notify the caller by sending a negative value.
         */
        int key = (data >> 1) & KEY_MASK;

        if ((data & TWO_PACKETS_MASK))
                /* Part of a 2 packets-command */
                key = -key;

        return key;
}

static void key_up(struct hid_device *hid, struct appleir *appleir, int key)
{
        input_report_key(appleir->input_dev, key, 0);
        input_sync(appleir->input_dev);
}

static void key_down(struct hid_device *hid, struct appleir *appleir, int key)
{
        input_report_key(appleir->input_dev, key, 1);
        input_sync(appleir->input_dev);
}

static void battery_flat(struct appleir *appleir)
{
        dev_err(&appleir->input_dev->dev, "possible flat battery?\n");
}

static void key_up_tick(struct timer_list *t)
{
        struct appleir *appleir = timer_container_of(appleir, t, key_up_timer);
        struct hid_device *hid = appleir->hid;
        unsigned long flags;

        spin_lock_irqsave(&appleir->lock, flags);
        if (appleir->current_key) {
                key_up(hid, appleir, appleir->current_key);
                appleir->current_key = 0;
        }
        spin_unlock_irqrestore(&appleir->lock, flags);
}

static int appleir_raw_event(struct hid_device *hid, struct hid_report *report,
         u8 *data, int len)
{
        struct appleir *appleir = hid_get_drvdata(hid);
        static const u8 keydown[] = { 0x25, 0x87, 0xee };
        static const u8 keyrepeat[] = { 0x26, };
        static const u8 flatbattery[] = { 0x25, 0x87, 0xe0 };
        unsigned long flags;

        if (len != 5 || !(hid->claimed & HID_CLAIMED_INPUT))
                goto out;

        if (!memcmp(data, keydown, sizeof(keydown))) {
                int index;

                spin_lock_irqsave(&appleir->lock, flags);
                /*
                 * If we already have a key down, take it up before marking
                 * this one down
                 */
                if (appleir->current_key)
                        key_up(hid, appleir, appleir->current_key);

                /* Handle dual packet commands */
                if (appleir->prev_key_idx > 0)
                        index = appleir->prev_key_idx;
                else
                        index = get_key(data[4]);

                if (index >= 0) {
                        appleir->current_key = appleir->keymap[index];

                        key_down(hid, appleir, appleir->current_key);
                        /*
                         * Remote doesn't do key up, either pull them up, in
                         * the test above, or here set a timer which pulls
                         * them up after 1/8 s
                         */
                        mod_timer(&appleir->key_up_timer, jiffies + HZ / 8);
                        appleir->prev_key_idx = 0;
                } else
                        /* Remember key for next packet */
                        appleir->prev_key_idx = -index;
                spin_unlock_irqrestore(&appleir->lock, flags);
                goto out;
        }

        appleir->prev_key_idx = 0;

        if (!memcmp(data, keyrepeat, sizeof(keyrepeat))) {
                key_down(hid, appleir, appleir->current_key);
                /*
                 * Remote doesn't do key up, either pull them up, in the test
                 * above, or here set a timer which pulls them up after 1/8 s
                 */
                mod_timer(&appleir->key_up_timer, jiffies + HZ / 8);
                goto out;
        }

        if (!memcmp(data, flatbattery, sizeof(flatbattery))) {
                battery_flat(appleir);
                /* Fall through */
        }

out:
        /* let hidraw and hiddev handle the report */
        return 0;
}

static int appleir_input_configured(struct hid_device *hid,
                struct hid_input *hidinput)
{
        struct input_dev *input_dev = hidinput->input;
        struct appleir *appleir = hid_get_drvdata(hid);
        int i;

        appleir->input_dev = input_dev;

        input_dev->keycode = appleir->keymap;
        input_dev->keycodesize = sizeof(unsigned short);
        input_dev->keycodemax = ARRAY_SIZE(appleir->keymap);

        input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_REP);

        memcpy(appleir->keymap, appleir_key_table, sizeof(appleir->keymap));
        for (i = 0; i < ARRAY_SIZE(appleir_key_table); i++)
                set_bit(appleir->keymap[i], input_dev->keybit);
        clear_bit(KEY_RESERVED, input_dev->keybit);

        return 0;
}

static int appleir_input_mapping(struct hid_device *hid,
                struct hid_input *hi, struct hid_field *field,
                struct hid_usage *usage, unsigned long **bit, int *max)
{
        return -1;
}

static int appleir_probe(struct hid_device *hid, const struct hid_device_id *id)
{
        int ret;
        struct appleir *appleir;

        appleir = devm_kzalloc(&hid->dev, sizeof(struct appleir), GFP_KERNEL);
        if (!appleir)
                return -ENOMEM;

        appleir->hid = hid;

        /* force input as some remotes bypass the input registration */
        hid->quirks |= HID_QUIRK_HIDINPUT_FORCE;

        spin_lock_init(&appleir->lock);
        timer_setup(&appleir->key_up_timer, key_up_tick, 0);

        hid_set_drvdata(hid, appleir);

        ret = hid_parse(hid);
        if (ret) {
                hid_err(hid, "parse failed\n");
                goto fail;
        }

        ret = hid_hw_start(hid, HID_CONNECT_DEFAULT | HID_CONNECT_HIDDEV_FORCE);
        if (ret) {
                hid_err(hid, "hw start failed\n");
                goto fail;
        }

        return 0;
fail:
        devm_kfree(&hid->dev, appleir);
        return ret;
}

static void appleir_remove(struct hid_device *hid)
{
        struct appleir *appleir = hid_get_drvdata(hid);
        hid_hw_stop(hid);
        timer_delete_sync(&appleir->key_up_timer);
}

static const struct hid_device_id appleir_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL) },
        { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL2) },
        { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL3) },
        { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL4) },
        { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL5) },
        { }
};
MODULE_DEVICE_TABLE(hid, appleir_devices);

static struct hid_driver appleir_driver = {
        .name = "appleir",
        .id_table = appleir_devices,
        .raw_event = appleir_raw_event,
        .input_configured = appleir_input_configured,
        .probe = appleir_probe,
        .remove = appleir_remove,
        .input_mapping = appleir_input_mapping,
};
module_hid_driver(appleir_driver);