/*
 *  Force feedback driver for USB HID PID compliant devices
 *
 *  Copyright (c) 2005, 2006 Anssi Hannula <anssi.hannula@gmail.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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/* #define DEBUG */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/input.h>
#include <linux/slab.h>
#include <linux/usb.h>

#include <linux/hid.h>

#include "usbhid.h"

#define PID_EFFECTS_MAX         64

/* Report usage table used to put reports into an array */

#define PID_SET_EFFECT          0
#define PID_EFFECT_OPERATION    1
#define PID_DEVICE_GAIN         2
#define PID_POOL                3
#define PID_BLOCK_LOAD          4
#define PID_BLOCK_FREE          5
#define PID_DEVICE_CONTROL      6
#define PID_CREATE_NEW_EFFECT   7

#define PID_REQUIRED_REPORTS    7

#define PID_SET_ENVELOPE        8
#define PID_SET_CONDITION       9
#define PID_SET_PERIODIC        10
#define PID_SET_CONSTANT        11
#define PID_SET_RAMP            12
static const u8 pidff_reports[] = {
        0x21, 0x77, 0x7d, 0x7f, 0x89, 0x90, 0x96, 0xab,
        0x5a, 0x5f, 0x6e, 0x73, 0x74
};

/* device_control is really 0x95, but 0x96 specified as it is the usage of
the only field in that report */

/* Value usage tables used to put fields and values into arrays */

#define PID_EFFECT_BLOCK_INDEX  0

#define PID_DURATION            1
#define PID_GAIN                2
#define PID_TRIGGER_BUTTON      3
#define PID_TRIGGER_REPEAT_INT  4
#define PID_DIRECTION_ENABLE    5
#define PID_START_DELAY         6
static const u8 pidff_set_effect[] = {
        0x22, 0x50, 0x52, 0x53, 0x54, 0x56, 0xa7
};

#define PID_ATTACK_LEVEL        1
#define PID_ATTACK_TIME         2
#define PID_FADE_LEVEL          3
#define PID_FADE_TIME           4
static const u8 pidff_set_envelope[] = { 0x22, 0x5b, 0x5c, 0x5d, 0x5e };

#define PID_PARAM_BLOCK_OFFSET  1
#define PID_CP_OFFSET           2
#define PID_POS_COEFFICIENT     3
#define PID_NEG_COEFFICIENT     4
#define PID_POS_SATURATION      5
#define PID_NEG_SATURATION      6
#define PID_DEAD_BAND           7
static const u8 pidff_set_condition[] = {
        0x22, 0x23, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65
};

#define PID_MAGNITUDE           1
#define PID_OFFSET              2
#define PID_PHASE               3
#define PID_PERIOD              4
static const u8 pidff_set_periodic[] = { 0x22, 0x70, 0x6f, 0x71, 0x72 };
static const u8 pidff_set_constant[] = { 0x22, 0x70 };

#define PID_RAMP_START          1
#define PID_RAMP_END            2
static const u8 pidff_set_ramp[] = { 0x22, 0x75, 0x76 };

#define PID_RAM_POOL_AVAILABLE  1
static const u8 pidff_block_load[] = { 0x22, 0xac };

#define PID_LOOP_COUNT          1
static const u8 pidff_effect_operation[] = { 0x22, 0x7c };

static const u8 pidff_block_free[] = { 0x22 };

#define PID_DEVICE_GAIN_FIELD   0
static const u8 pidff_device_gain[] = { 0x7e };

#define PID_RAM_POOL_SIZE       0
#define PID_SIMULTANEOUS_MAX    1
#define PID_DEVICE_MANAGED_POOL 2
static const u8 pidff_pool[] = { 0x80, 0x83, 0xa9 };

/* Special field key tables used to put special field keys into arrays */

#define PID_ENABLE_ACTUATORS    0
#define PID_RESET               1
static const u8 pidff_device_control[] = { 0x97, 0x9a };

#define PID_CONSTANT    0
#define PID_RAMP        1
#define PID_SQUARE      2
#define PID_SINE        3
#define PID_TRIANGLE    4
#define PID_SAW_UP      5
#define PID_SAW_DOWN    6
#define PID_SPRING      7
#define PID_DAMPER      8
#define PID_INERTIA     9
#define PID_FRICTION    10
static const u8 pidff_effect_types[] = {
        0x26, 0x27, 0x30, 0x31, 0x32, 0x33, 0x34,
        0x40, 0x41, 0x42, 0x43
};

#define PID_BLOCK_LOAD_SUCCESS  0
#define PID_BLOCK_LOAD_FULL     1
static const u8 pidff_block_load_status[] = { 0x8c, 0x8d };

#define PID_EFFECT_START        0
#define PID_EFFECT_STOP         1
static const u8 pidff_effect_operation_status[] = { 0x79, 0x7b };

struct pidff_usage {
        struct hid_field *field;
        s32 *value;
};

struct pidff_device {
        struct hid_device *hid;

        struct hid_report *reports[sizeof(pidff_reports)];

        struct pidff_usage set_effect[sizeof(pidff_set_effect)];
        struct pidff_usage set_envelope[sizeof(pidff_set_envelope)];
        struct pidff_usage set_condition[sizeof(pidff_set_condition)];
        struct pidff_usage set_periodic[sizeof(pidff_set_periodic)];
        struct pidff_usage set_constant[sizeof(pidff_set_constant)];
        struct pidff_usage set_ramp[sizeof(pidff_set_ramp)];

        struct pidff_usage device_gain[sizeof(pidff_device_gain)];
        struct pidff_usage block_load[sizeof(pidff_block_load)];
        struct pidff_usage pool[sizeof(pidff_pool)];
        struct pidff_usage effect_operation[sizeof(pidff_effect_operation)];
        struct pidff_usage block_free[sizeof(pidff_block_free)];

        /* Special field is a field that is not composed of
           usage<->value pairs that pidff_usage values are */

        /* Special field in create_new_effect */
        struct hid_field *create_new_effect_type;

        /* Special fields in set_effect */
        struct hid_field *set_effect_type;
        struct hid_field *effect_direction;

        /* Special field in device_control */
        struct hid_field *device_control;

        /* Special field in block_load */
        struct hid_field *block_load_status;

        /* Special field in effect_operation */
        struct hid_field *effect_operation_status;

        int control_id[sizeof(pidff_device_control)];
        int type_id[sizeof(pidff_effect_types)];
        int status_id[sizeof(pidff_block_load_status)];
        int operation_id[sizeof(pidff_effect_operation_status)];

        int pid_id[PID_EFFECTS_MAX];
};

/*
 * Scale an unsigned value with range 0..max for the given field
 */
static int pidff_rescale(int i, int max, struct hid_field *field)
{
        return i * (field->logical_maximum - field->logical_minimum) / max +
            field->logical_minimum;
}

/*
 * Scale a signed value in range -0x8000..0x7fff for the given field
 */
static int pidff_rescale_signed(int i, struct hid_field *field)
{
        return i == 0 ? 0 : i >
            0 ? i * field->logical_maximum / 0x7fff : i *
            field->logical_minimum / -0x8000;
}

static void pidff_set(struct pidff_usage *usage, u16 value)
{
        usage->value[0] = pidff_rescale(value, 0xffff, usage->field);
        pr_debug("calculated from %d to %d\n", value, usage->value[0]);
}

static void pidff_set_signed(struct pidff_usage *usage, s16 value)
{
        if (usage->field->logical_minimum < 0)
                usage->value[0] = pidff_rescale_signed(value, usage->field);
        else {
                if (value < 0)
                        usage->value[0] =
                            pidff_rescale(-value, 0x8000, usage->field);
                else
                        usage->value[0] =
                            pidff_rescale(value, 0x7fff, usage->field);
        }
        pr_debug("calculated from %d to %d\n", value, usage->value[0]);
}

/*
 * Send envelope report to the device
 */
static void pidff_set_envelope_report(struct pidff_device *pidff,
                                      struct ff_envelope *envelope)
{
        pidff->set_envelope[PID_EFFECT_BLOCK_INDEX].value[0] =
            pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];

        pidff->set_envelope[PID_ATTACK_LEVEL].value[0] =
            pidff_rescale(envelope->attack_level >
                          0x7fff ? 0x7fff : envelope->attack_level, 0x7fff,
                          pidff->set_envelope[PID_ATTACK_LEVEL].field);
        pidff->set_envelope[PID_FADE_LEVEL].value[0] =
            pidff_rescale(envelope->fade_level >
                          0x7fff ? 0x7fff : envelope->fade_level, 0x7fff,
                          pidff->set_envelope[PID_FADE_LEVEL].field);

        pidff->set_envelope[PID_ATTACK_TIME].value[0] = envelope->attack_length;
        pidff->set_envelope[PID_FADE_TIME].value[0] = envelope->fade_length;

        hid_dbg(pidff->hid, "attack %u => %d\n",
                envelope->attack_level,
                pidff->set_envelope[PID_ATTACK_LEVEL].value[0]);

        usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_ENVELOPE],
                          USB_DIR_OUT);
}

/*
 * Test if the new envelope differs from old one
 */
static int pidff_needs_set_envelope(struct ff_envelope *envelope,
                                    struct ff_envelope *old)
{
        return envelope->attack_level != old->attack_level ||
               envelope->fade_level != old->fade_level ||
               envelope->attack_length != old->attack_length ||
               envelope->fade_length != old->fade_length;
}

/*
 * Send constant force report to the device
 */
static void pidff_set_constant_force_report(struct pidff_device *pidff,
                                            struct ff_effect *effect)
{
        pidff->set_constant[PID_EFFECT_BLOCK_INDEX].value[0] =
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];
        pidff_set_signed(&pidff->set_constant[PID_MAGNITUDE],
                         effect->u.constant.level);

        usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_CONSTANT],
                          USB_DIR_OUT);
}

/*
 * Test if the constant parameters have changed between effects
 */
static int pidff_needs_set_constant(struct ff_effect *effect,
                                    struct ff_effect *old)
{
        return effect->u.constant.level != old->u.constant.level;
}

/*
 * Send set effect report to the device
 */
static void pidff_set_effect_report(struct pidff_device *pidff,
                                    struct ff_effect *effect)
{
        pidff->set_effect[PID_EFFECT_BLOCK_INDEX].value[0] =
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];
        pidff->set_effect_type->value[0] =
                pidff->create_new_effect_type->value[0];
        pidff->set_effect[PID_DURATION].value[0] = effect->replay.length;
        pidff->set_effect[PID_TRIGGER_BUTTON].value[0] = effect->trigger.button;
        pidff->set_effect[PID_TRIGGER_REPEAT_INT].value[0] =
                effect->trigger.interval;
        pidff->set_effect[PID_GAIN].value[0] =
                pidff->set_effect[PID_GAIN].field->logical_maximum;
        pidff->set_effect[PID_DIRECTION_ENABLE].value[0] = 1;
        pidff->effect_direction->value[0] =
                pidff_rescale(effect->direction, 0xffff,
                                pidff->effect_direction);
        pidff->set_effect[PID_START_DELAY].value[0] = effect->replay.delay;

        usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_EFFECT],
                          USB_DIR_OUT);
}

/*
 * Test if the values used in set_effect have changed
 */
static int pidff_needs_set_effect(struct ff_effect *effect,
                                  struct ff_effect *old)
{
        return effect->replay.length != old->replay.length ||
               effect->trigger.interval != old->trigger.interval ||
               effect->trigger.button != old->trigger.button ||
               effect->direction != old->direction ||
               effect->replay.delay != old->replay.delay;
}

/*
 * Send periodic effect report to the device
 */
static void pidff_set_periodic_report(struct pidff_device *pidff,
                                      struct ff_effect *effect)
{
        pidff->set_periodic[PID_EFFECT_BLOCK_INDEX].value[0] =
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];
        pidff_set_signed(&pidff->set_periodic[PID_MAGNITUDE],
                         effect->u.periodic.magnitude);
        pidff_set_signed(&pidff->set_periodic[PID_OFFSET],
                         effect->u.periodic.offset);
        pidff_set(&pidff->set_periodic[PID_PHASE], effect->u.periodic.phase);
        pidff->set_periodic[PID_PERIOD].value[0] = effect->u.periodic.period;

        usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_PERIODIC],
                          USB_DIR_OUT);

}

/*
 * Test if periodic effect parameters have changed
 */
static int pidff_needs_set_periodic(struct ff_effect *effect,
                                    struct ff_effect *old)
{
        return effect->u.periodic.magnitude != old->u.periodic.magnitude ||
               effect->u.periodic.offset != old->u.periodic.offset ||
               effect->u.periodic.phase != old->u.periodic.phase ||
               effect->u.periodic.period != old->u.periodic.period;
}

/*
 * Send condition effect reports to the device
 */
static void pidff_set_condition_report(struct pidff_device *pidff,
                                       struct ff_effect *effect)
{
        int i;

        pidff->set_condition[PID_EFFECT_BLOCK_INDEX].value[0] =
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];

        for (i = 0; i < 2; i++) {
                pidff->set_condition[PID_PARAM_BLOCK_OFFSET].value[0] = i;
                pidff_set_signed(&pidff->set_condition[PID_CP_OFFSET],
                                 effect->u.condition[i].center);
                pidff_set_signed(&pidff->set_condition[PID_POS_COEFFICIENT],
                                 effect->u.condition[i].right_coeff);
                pidff_set_signed(&pidff->set_condition[PID_NEG_COEFFICIENT],
                                 effect->u.condition[i].left_coeff);
                pidff_set(&pidff->set_condition[PID_POS_SATURATION],
                          effect->u.condition[i].right_saturation);
                pidff_set(&pidff->set_condition[PID_NEG_SATURATION],
                          effect->u.condition[i].left_saturation);
                pidff_set(&pidff->set_condition[PID_DEAD_BAND],
                          effect->u.condition[i].deadband);
                usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_CONDITION],
                                  USB_DIR_OUT);
        }
}

/*
 * Test if condition effect parameters have changed
 */
static int pidff_needs_set_condition(struct ff_effect *effect,
                                     struct ff_effect *old)
{
        int i;
        int ret = 0;

        for (i = 0; i < 2; i++) {
                struct ff_condition_effect *cond = &effect->u.condition[i];
                struct ff_condition_effect *old_cond = &old->u.condition[i];

                ret |= cond->center != old_cond->center ||
                       cond->right_coeff != old_cond->right_coeff ||
                       cond->left_coeff != old_cond->left_coeff ||
                       cond->right_saturation != old_cond->right_saturation ||
                       cond->left_saturation != old_cond->left_saturation ||
                       cond->deadband != old_cond->deadband;
        }

        return ret;
}

/*
 * Send ramp force report to the device
 */
static void pidff_set_ramp_force_report(struct pidff_device *pidff,
                                        struct ff_effect *effect)
{
        pidff->set_ramp[PID_EFFECT_BLOCK_INDEX].value[0] =
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];
        pidff_set_signed(&pidff->set_ramp[PID_RAMP_START],
                         effect->u.ramp.start_level);
        pidff_set_signed(&pidff->set_ramp[PID_RAMP_END],
                         effect->u.ramp.end_level);
        usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_RAMP],
                          USB_DIR_OUT);
}

/*
 * Test if ramp force parameters have changed
 */
static int pidff_needs_set_ramp(struct ff_effect *effect, struct ff_effect *old)
{
        return effect->u.ramp.start_level != old->u.ramp.start_level ||
               effect->u.ramp.end_level != old->u.ramp.end_level;
}

/*
 * Send a request for effect upload to the device
 *
 * Returns 0 if device reported success, -ENOSPC if the device reported memory
 * is full. Upon unknown response the function will retry for 60 times, if
 * still unsuccessful -EIO is returned.
 */
static int pidff_request_effect_upload(struct pidff_device *pidff, int efnum)
{
        int j;

        pidff->create_new_effect_type->value[0] = efnum;
        usbhid_submit_report(pidff->hid, pidff->reports[PID_CREATE_NEW_EFFECT],
                          USB_DIR_OUT);
        hid_dbg(pidff->hid, "create_new_effect sent, type: %d\n", efnum);

        pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0] = 0;
        pidff->block_load_status->value[0] = 0;
        usbhid_wait_io(pidff->hid);

        for (j = 0; j < 60; j++) {
                hid_dbg(pidff->hid, "pid_block_load requested\n");
                usbhid_submit_report(pidff->hid, pidff->reports[PID_BLOCK_LOAD],
                                  USB_DIR_IN);
                usbhid_wait_io(pidff->hid);
                if (pidff->block_load_status->value[0] ==
                    pidff->status_id[PID_BLOCK_LOAD_SUCCESS]) {
                        hid_dbg(pidff->hid, "device reported free memory: %d bytes\n",
                                 pidff->block_load[PID_RAM_POOL_AVAILABLE].value ?
                                 pidff->block_load[PID_RAM_POOL_AVAILABLE].value[0] : -1);
                        return 0;
                }
                if (pidff->block_load_status->value[0] ==
                    pidff->status_id[PID_BLOCK_LOAD_FULL]) {
                        hid_dbg(pidff->hid, "not enough memory free: %d bytes\n",
                                pidff->block_load[PID_RAM_POOL_AVAILABLE].value ?
                                pidff->block_load[PID_RAM_POOL_AVAILABLE].value[0] : -1);
                        return -ENOSPC;
                }
        }
        hid_err(pidff->hid, "pid_block_load failed 60 times\n");
        return -EIO;
}

/*
 * Play the effect with PID id n times
 */
static void pidff_playback_pid(struct pidff_device *pidff, int pid_id, int n)
{
        pidff->effect_operation[PID_EFFECT_BLOCK_INDEX].value[0] = pid_id;

        if (n == 0) {
                pidff->effect_operation_status->value[0] =
                        pidff->operation_id[PID_EFFECT_STOP];
        } else {
                pidff->effect_operation_status->value[0] =
                        pidff->operation_id[PID_EFFECT_START];
                pidff->effect_operation[PID_LOOP_COUNT].value[0] = n;
        }

        usbhid_submit_report(pidff->hid, pidff->reports[PID_EFFECT_OPERATION],
                          USB_DIR_OUT);
}

/**
 * Play the effect with effect id @effect_id for @value times
 */
static int pidff_playback(struct input_dev *dev, int effect_id, int value)
{
        struct pidff_device *pidff = dev->ff->private;

        pidff_playback_pid(pidff, pidff->pid_id[effect_id], value);

        return 0;
}

/*
 * Erase effect with PID id
 */
static void pidff_erase_pid(struct pidff_device *pidff, int pid_id)
{
        pidff->block_free[PID_EFFECT_BLOCK_INDEX].value[0] = pid_id;
        usbhid_submit_report(pidff->hid, pidff->reports[PID_BLOCK_FREE],
                          USB_DIR_OUT);
}

/*
 * Stop and erase effect with effect_id
 */
static int pidff_erase_effect(struct input_dev *dev, int effect_id)
{
        struct pidff_device *pidff = dev->ff->private;
        int pid_id = pidff->pid_id[effect_id];

        hid_dbg(pidff->hid, "starting to erase %d/%d\n",
                effect_id, pidff->pid_id[effect_id]);
        /* Wait for the queue to clear. We do not want a full fifo to
           prevent the effect removal. */
        usbhid_wait_io(pidff->hid);
        pidff_playback_pid(pidff, pid_id, 0);
        pidff_erase_pid(pidff, pid_id);

        return 0;
}

/*
 * Effect upload handler
 */
static int pidff_upload_effect(struct input_dev *dev, struct ff_effect *effect,
                               struct ff_effect *old)
{
        struct pidff_device *pidff = dev->ff->private;
        int type_id;
        int error;

        switch (effect->type) {
        case FF_CONSTANT:
                if (!old) {
                        error = pidff_request_effect_upload(pidff,
                                        pidff->type_id[PID_CONSTANT]);
                        if (error)
                                return error;
                }
                if (!old || pidff_needs_set_effect(effect, old))
                        pidff_set_effect_report(pidff, effect);
                if (!old || pidff_needs_set_constant(effect, old))
                        pidff_set_constant_force_report(pidff, effect);
                if (!old ||
                    pidff_needs_set_envelope(&effect->u.constant.envelope,
                                        &old->u.constant.envelope))
                        pidff_set_envelope_report(pidff,
                                        &effect->u.constant.envelope);
                break;

        case FF_PERIODIC:
                if (!old) {
                        switch (effect->u.periodic.waveform) {
                        case FF_SQUARE:
                                type_id = PID_SQUARE;
                                break;
                        case FF_TRIANGLE:
                                type_id = PID_TRIANGLE;
                                break;
                        case FF_SINE:
                                type_id = PID_SINE;
                                break;
                        case FF_SAW_UP:
                                type_id = PID_SAW_UP;
                                break;
                        case FF_SAW_DOWN:
                                type_id = PID_SAW_DOWN;
                                break;
                        default:
                                hid_err(pidff->hid, "invalid waveform\n");
                                return -EINVAL;
                        }

                        error = pidff_request_effect_upload(pidff,
                                        pidff->type_id[type_id]);
                        if (error)
                                return error;
                }
                if (!old || pidff_needs_set_effect(effect, old))
                        pidff_set_effect_report(pidff, effect);
                if (!old || pidff_needs_set_periodic(effect, old))
                        pidff_set_periodic_report(pidff, effect);
                if (!old ||
                    pidff_needs_set_envelope(&effect->u.periodic.envelope,
                                        &old->u.periodic.envelope))
                        pidff_set_envelope_report(pidff,
                                        &effect->u.periodic.envelope);
                break;

        case FF_RAMP:
                if (!old) {
                        error = pidff_request_effect_upload(pidff,
                                        pidff->type_id[PID_RAMP]);
                        if (error)
                                return error;
                }
                if (!old || pidff_needs_set_effect(effect, old))
                        pidff_set_effect_report(pidff, effect);
                if (!old || pidff_needs_set_ramp(effect, old))
                        pidff_set_ramp_force_report(pidff, effect);
                if (!old ||
                    pidff_needs_set_envelope(&effect->u.ramp.envelope,
                                        &old->u.ramp.envelope))
                        pidff_set_envelope_report(pidff,
                                        &effect->u.ramp.envelope);
                break;

        case FF_SPRING:
                if (!old) {
                        error = pidff_request_effect_upload(pidff,
                                        pidff->type_id[PID_SPRING]);
                        if (error)
                                return error;
                }
                if (!old || pidff_needs_set_effect(effect, old))
                        pidff_set_effect_report(pidff, effect);
                if (!old || pidff_needs_set_condition(effect, old))
                        pidff_set_condition_report(pidff, effect);
                break;

        case FF_FRICTION:
                if (!old) {
                        error = pidff_request_effect_upload(pidff,
                                        pidff->type_id[PID_FRICTION]);
                        if (error)
                                return error;
                }
                if (!old || pidff_needs_set_effect(effect, old))
                        pidff_set_effect_report(pidff, effect);
                if (!old || pidff_needs_set_condition(effect, old))
                        pidff_set_condition_report(pidff, effect);
                break;

        case FF_DAMPER:
                if (!old) {
                        error = pidff_request_effect_upload(pidff,
                                        pidff->type_id[PID_DAMPER]);
                        if (error)
                                return error;
                }
                if (!old || pidff_needs_set_effect(effect, old))
                        pidff_set_effect_report(pidff, effect);
                if (!old || pidff_needs_set_condition(effect, old))
                        pidff_set_condition_report(pidff, effect);
                break;

        case FF_INERTIA:
                if (!old) {
                        error = pidff_request_effect_upload(pidff,
                                        pidff->type_id[PID_INERTIA]);
                        if (error)
                                return error;
                }
                if (!old || pidff_needs_set_effect(effect, old))
                        pidff_set_effect_report(pidff, effect);
                if (!old || pidff_needs_set_condition(effect, old))
                        pidff_set_condition_report(pidff, effect);
                break;

        default:
                hid_err(pidff->hid, "invalid type\n");
                return -EINVAL;
        }

        if (!old)
                pidff->pid_id[effect->id] =
                    pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];

        hid_dbg(pidff->hid, "uploaded\n");

        return 0;
}

/*
 * set_gain() handler
 */
static void pidff_set_gain(struct input_dev *dev, u16 gain)
{
        struct pidff_device *pidff = dev->ff->private;

        pidff_set(&pidff->device_gain[PID_DEVICE_GAIN_FIELD], gain);
        usbhid_submit_report(pidff->hid, pidff->reports[PID_DEVICE_GAIN],
                          USB_DIR_OUT);
}

static void pidff_autocenter(struct pidff_device *pidff, u16 magnitude)
{
        struct hid_field *field =
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].field;

        if (!magnitude) {
                pidff_playback_pid(pidff, field->logical_minimum, 0);
                return;
        }

        pidff_playback_pid(pidff, field->logical_minimum, 1);

        pidff->set_effect[PID_EFFECT_BLOCK_INDEX].value[0] =
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].field->logical_minimum;
        pidff->set_effect_type->value[0] = pidff->type_id[PID_SPRING];
        pidff->set_effect[PID_DURATION].value[0] = 0;
        pidff->set_effect[PID_TRIGGER_BUTTON].value[0] = 0;
        pidff->set_effect[PID_TRIGGER_REPEAT_INT].value[0] = 0;
        pidff_set(&pidff->set_effect[PID_GAIN], magnitude);
        pidff->set_effect[PID_DIRECTION_ENABLE].value[0] = 1;
        pidff->set_effect[PID_START_DELAY].value[0] = 0;

        usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_EFFECT],
                          USB_DIR_OUT);
}

/*
 * pidff_set_autocenter() handler
 */
static void pidff_set_autocenter(struct input_dev *dev, u16 magnitude)
{
        struct pidff_device *pidff = dev->ff->private;

        pidff_autocenter(pidff, magnitude);
}

/*
 * Find fields from a report and fill a pidff_usage
 */
static int pidff_find_fields(struct pidff_usage *usage, const u8 *table,
                             struct hid_report *report, int count, int strict)
{
        int i, j, k, found;

        for (k = 0; k < count; k++) {
                found = 0;
                for (i = 0; i < report->maxfield; i++) {
                        if (report->field[i]->maxusage !=
                            report->field[i]->report_count) {
                                pr_debug("maxusage and report_count do not match, skipping\n");
                                continue;
                        }
                        for (j = 0; j < report->field[i]->maxusage; j++) {
                                if (report->field[i]->usage[j].hid ==
                                    (HID_UP_PID | table[k])) {
                                        pr_debug("found %d at %d->%d\n",
                                                 k, i, j);
                                        usage[k].field = report->field[i];
                                        usage[k].value =
                                                &report->field[i]->value[j];
                                        found = 1;
                                        break;
                                }
                        }
                        if (found)
                                break;
                }
                if (!found && strict) {
                        pr_debug("failed to locate %d\n", k);
                        return -1;
                }
        }
        return 0;
}

/*
 * Return index into pidff_reports for the given usage
 */
static int pidff_check_usage(int usage)
{
        int i;

        for (i = 0; i < sizeof(pidff_reports); i++)
                if (usage == (HID_UP_PID | pidff_reports[i]))
                        return i;

        return -1;
}

/*
 * Find the reports and fill pidff->reports[]
 * report_type specifies either OUTPUT or FEATURE reports
 */
static void pidff_find_reports(struct hid_device *hid, int report_type,
                               struct pidff_device *pidff)
{
        struct hid_report *report;
        int i, ret;

        list_for_each_entry(report,
                            &hid->report_enum[report_type].report_list, list) {
                if (report->maxfield < 1)
                        continue;
                ret = pidff_check_usage(report->field[0]->logical);
                if (ret != -1) {
                        hid_dbg(hid, "found usage 0x%02x from field->logical\n",
                                pidff_reports[ret]);
                        pidff->reports[ret] = report;
                        continue;
                }

                /*
                 * Sometimes logical collections are stacked to indicate
                 * different usages for the report and the field, in which
                 * case we want the usage of the parent. However, Linux HID
                 * implementation hides this fact, so we have to dig it up
                 * ourselves
                 */
                i = report->field[0]->usage[0].collection_index;
                if (i <= 0 ||
                    hid->collection[i - 1].type != HID_COLLECTION_LOGICAL)
                        continue;
                ret = pidff_check_usage(hid->collection[i - 1].usage);
                if (ret != -1 && !pidff->reports[ret]) {
                        hid_dbg(hid,
                                "found usage 0x%02x from collection array\n",
                                pidff_reports[ret]);
                        pidff->reports[ret] = report;
                }
        }
}

/*
 * Test if the required reports have been found
 */
static int pidff_reports_ok(struct pidff_device *pidff)
{
        int i;

        for (i = 0; i <= PID_REQUIRED_REPORTS; i++) {
                if (!pidff->reports[i]) {
                        hid_dbg(pidff->hid, "%d missing\n", i);
                        return 0;
                }
        }

        return 1;
}

/*
 * Find a field with a specific usage within a report
 */
static struct hid_field *pidff_find_special_field(struct hid_report *report,
                                                  int usage, int enforce_min)
{
        int i;

        for (i = 0; i < report->maxfield; i++) {
                if (report->field[i]->logical == (HID_UP_PID | usage) &&
                    report->field[i]->report_count > 0) {
                        if (!enforce_min ||
                            report->field[i]->logical_minimum == 1)
                                return report->field[i];
                        else {
                                pr_err("logical_minimum is not 1 as it should be\n");
                                return NULL;
                        }
                }
        }
        return NULL;
}

/*
 * Fill a pidff->*_id struct table
 */
static int pidff_find_special_keys(int *keys, struct hid_field *fld,
                                   const u8 *usagetable, int count)
{

        int i, j;
        int found = 0;

        for (i = 0; i < count; i++) {
                for (j = 0; j < fld->maxusage; j++) {
                        if (fld->usage[j].hid == (HID_UP_PID | usagetable[i])) {
                                keys[i] = j + 1;
                                found++;
                                break;
                        }
                }
        }
        return found;
}

#define PIDFF_FIND_SPECIAL_KEYS(keys, field, name) \
        pidff_find_special_keys(pidff->keys, pidff->field, pidff_ ## name, \
                sizeof(pidff_ ## name))

/*
 * Find and check the special fields
 */
static int pidff_find_special_fields(struct pidff_device *pidff)
{
        hid_dbg(pidff->hid, "finding special fields\n");

        pidff->create_new_effect_type =
                pidff_find_special_field(pidff->reports[PID_CREATE_NEW_EFFECT],
                                         0x25, 1);
        pidff->set_effect_type =
                pidff_find_special_field(pidff->reports[PID_SET_EFFECT],
                                         0x25, 1);
        pidff->effect_direction =
                pidff_find_special_field(pidff->reports[PID_SET_EFFECT],
                                         0x57, 0);
        pidff->device_control =
                pidff_find_special_field(pidff->reports[PID_DEVICE_CONTROL],
                                         0x96, 1);
        pidff->block_load_status =
                pidff_find_special_field(pidff->reports[PID_BLOCK_LOAD],
                                         0x8b, 1);
        pidff->effect_operation_status =
                pidff_find_special_field(pidff->reports[PID_EFFECT_OPERATION],
                                         0x78, 1);

        hid_dbg(pidff->hid, "search done\n");

        if (!pidff->create_new_effect_type || !pidff->set_effect_type) {
                hid_err(pidff->hid, "effect lists not found\n");
                return -1;
        }

        if (!pidff->effect_direction) {
                hid_err(pidff->hid, "direction field not found\n");
                return -1;
        }

        if (!pidff->device_control) {
                hid_err(pidff->hid, "device control field not found\n");
                return -1;
        }

        if (!pidff->block_load_status) {
                hid_err(pidff->hid, "block load status field not found\n");
                return -1;
        }

        if (!pidff->effect_operation_status) {
                hid_err(pidff->hid, "effect operation field not found\n");
                return -1;
        }

        pidff_find_special_keys(pidff->control_id, pidff->device_control,
                                pidff_device_control,
                                sizeof(pidff_device_control));

        PIDFF_FIND_SPECIAL_KEYS(control_id, device_control, device_control);

        if (!PIDFF_FIND_SPECIAL_KEYS(type_id, create_new_effect_type,
                                     effect_types)) {
                hid_err(pidff->hid, "no effect types found\n");
                return -1;
        }

        if (PIDFF_FIND_SPECIAL_KEYS(status_id, block_load_status,
                                    block_load_status) !=
                        sizeof(pidff_block_load_status)) {
                hid_err(pidff->hid,
                        "block load status identifiers not found\n");
                return -1;
        }

        if (PIDFF_FIND_SPECIAL_KEYS(operation_id, effect_operation_status,
                                    effect_operation_status) !=
                        sizeof(pidff_effect_operation_status)) {
                hid_err(pidff->hid, "effect operation identifiers not found\n");
                return -1;

        }

        return 0;
}

/**
 * Find the implemented effect types
 */
static int pidff_find_effects(struct pidff_device *pidff,
                              struct input_dev *dev)
{
        int i;

        for (i = 0; i < sizeof(pidff_effect_types); i++) {
                int pidff_type = pidff->type_id[i];
                if (pidff->set_effect_type->usage[pidff_type].hid !=
                    pidff->create_new_effect_type->usage[pidff_type].hid) {
                        hid_err(pidff->hid,
                                "effect type number %d is invalid\n", i);
                        return -1;
                }
        }

        if (pidff->type_id[PID_CONSTANT])
                set_bit(FF_CONSTANT, dev->ffbit);
        if (pidff->type_id[PID_RAMP])
                set_bit(FF_RAMP, dev->ffbit);
        if (pidff->type_id[PID_SQUARE]) {
                set_bit(FF_SQUARE, dev->ffbit);
                set_bit(FF_PERIODIC, dev->ffbit);
        }
        if (pidff->type_id[PID_SINE]) {
                set_bit(FF_SINE, dev->ffbit);
                set_bit(FF_PERIODIC, dev->ffbit);
        }
        if (pidff->type_id[PID_TRIANGLE]) {
                set_bit(FF_TRIANGLE, dev->ffbit);
                set_bit(FF_PERIODIC, dev->ffbit);
        }
        if (pidff->type_id[PID_SAW_UP]) {
                set_bit(FF_SAW_UP, dev->ffbit);
                set_bit(FF_PERIODIC, dev->ffbit);
        }
        if (pidff->type_id[PID_SAW_DOWN]) {
                set_bit(FF_SAW_DOWN, dev->ffbit);
                set_bit(FF_PERIODIC, dev->ffbit);
        }
        if (pidff->type_id[PID_SPRING])
                set_bit(FF_SPRING, dev->ffbit);
        if (pidff->type_id[PID_DAMPER])
                set_bit(FF_DAMPER, dev->ffbit);
        if (pidff->type_id[PID_INERTIA])
                set_bit(FF_INERTIA, dev->ffbit);
        if (pidff->type_id[PID_FRICTION])
                set_bit(FF_FRICTION, dev->ffbit);

        return 0;

}

#define PIDFF_FIND_FIELDS(name, report, strict) \
        pidff_find_fields(pidff->name, pidff_ ## name, \
                pidff->reports[report], \
                sizeof(pidff_ ## name), strict)

/*
 * Fill and check the pidff_usages
 */
static int pidff_init_fields(struct pidff_device *pidff, struct input_dev *dev)
{
        int envelope_ok = 0;

        if (PIDFF_FIND_FIELDS(set_effect, PID_SET_EFFECT, 1)) {
                hid_err(pidff->hid, "unknown set_effect report layout\n");
                return -ENODEV;
        }

        PIDFF_FIND_FIELDS(block_load, PID_BLOCK_LOAD, 0);
        if (!pidff->block_load[PID_EFFECT_BLOCK_INDEX].value) {
                hid_err(pidff->hid, "unknown pid_block_load report layout\n");
                return -ENODEV;
        }

        if (PIDFF_FIND_FIELDS(effect_operation, PID_EFFECT_OPERATION, 1)) {
                hid_err(pidff->hid, "unknown effect_operation report layout\n");
                return -ENODEV;
        }

        if (PIDFF_FIND_FIELDS(block_free, PID_BLOCK_FREE, 1)) {
                hid_err(pidff->hid, "unknown pid_block_free report layout\n");
                return -ENODEV;
        }

        if (!PIDFF_FIND_FIELDS(set_envelope, PID_SET_ENVELOPE, 1))
                envelope_ok = 1;

        if (pidff_find_special_fields(pidff) || pidff_find_effects(pidff, dev))
                return -ENODEV;

        if (!envelope_ok) {
                if (test_and_clear_bit(FF_CONSTANT, dev->ffbit))
                        hid_warn(pidff->hid,
                                 "has constant effect but no envelope\n");
                if (test_and_clear_bit(FF_RAMP, dev->ffbit))
                        hid_warn(pidff->hid,
                                 "has ramp effect but no envelope\n");

                if (test_and_clear_bit(FF_PERIODIC, dev->ffbit))
                        hid_warn(pidff->hid,
                                 "has periodic effect but no envelope\n");
        }

        if (test_bit(FF_CONSTANT, dev->ffbit) &&
            PIDFF_FIND_FIELDS(set_constant, PID_SET_CONSTANT, 1)) {
                hid_warn(pidff->hid, "unknown constant effect layout\n");
                clear_bit(FF_CONSTANT, dev->ffbit);
        }

        if (test_bit(FF_RAMP, dev->ffbit) &&
            PIDFF_FIND_FIELDS(set_ramp, PID_SET_RAMP, 1)) {
                hid_warn(pidff->hid, "unknown ramp effect layout\n");
                clear_bit(FF_RAMP, dev->ffbit);
        }

        if ((test_bit(FF_SPRING, dev->ffbit) ||
             test_bit(FF_DAMPER, dev->ffbit) ||
             test_bit(FF_FRICTION, dev->ffbit) ||
             test_bit(FF_INERTIA, dev->ffbit)) &&
            PIDFF_FIND_FIELDS(set_condition, PID_SET_CONDITION, 1)) {
                hid_warn(pidff->hid, "unknown condition effect layout\n");
                clear_bit(FF_SPRING, dev->ffbit);
                clear_bit(FF_DAMPER, dev->ffbit);
                clear_bit(FF_FRICTION, dev->ffbit);
                clear_bit(FF_INERTIA, dev->ffbit);
        }

        if (test_bit(FF_PERIODIC, dev->ffbit) &&
            PIDFF_FIND_FIELDS(set_periodic, PID_SET_PERIODIC, 1)) {
                hid_warn(pidff->hid, "unknown periodic effect layout\n");
                clear_bit(FF_PERIODIC, dev->ffbit);
        }

        PIDFF_FIND_FIELDS(pool, PID_POOL, 0);

        if (!PIDFF_FIND_FIELDS(device_gain, PID_DEVICE_GAIN, 1))
                set_bit(FF_GAIN, dev->ffbit);

        return 0;
}

/*
 * Reset the device
 */
static void pidff_reset(struct pidff_device *pidff)
{
        struct hid_device *hid = pidff->hid;
        int i = 0;

        pidff->device_control->value[0] = pidff->control_id[PID_RESET];
        /* We reset twice as sometimes hid_wait_io isn't waiting long enough */
        usbhid_submit_report(hid, pidff->reports[PID_DEVICE_CONTROL], USB_DIR_OUT);
        usbhid_wait_io(hid);
        usbhid_submit_report(hid, pidff->reports[PID_DEVICE_CONTROL], USB_DIR_OUT);
        usbhid_wait_io(hid);

        pidff->device_control->value[0] =
                pidff->control_id[PID_ENABLE_ACTUATORS];
        usbhid_submit_report(hid, pidff->reports[PID_DEVICE_CONTROL], USB_DIR_OUT);
        usbhid_wait_io(hid);

        /* pool report is sometimes messed up, refetch it */
        usbhid_submit_report(hid, pidff->reports[PID_POOL], USB_DIR_IN);
        usbhid_wait_io(hid);

        if (pidff->pool[PID_SIMULTANEOUS_MAX].value) {
                while (pidff->pool[PID_SIMULTANEOUS_MAX].value[0] < 2) {
                        if (i++ > 20) {
                                hid_warn(pidff->hid,
                                         "device reports %d simultaneous effects\n",
                                         pidff->pool[PID_SIMULTANEOUS_MAX].value[0]);
                                break;
                        }
                        hid_dbg(pidff->hid, "pid_pool requested again\n");
                        usbhid_submit_report(hid, pidff->reports[PID_POOL],
                                          USB_DIR_IN);
                        usbhid_wait_io(hid);
                }
        }
}

/*
 * Test if autocenter modification is using the supported method
 */
static int pidff_check_autocenter(struct pidff_device *pidff,
                                  struct input_dev *dev)
{
        int error;

        /*
         * Let's find out if autocenter modification is supported
         * Specification doesn't specify anything, so we request an
         * effect upload and cancel it immediately. If the approved
         * effect id was one above the minimum, then we assume the first
         * effect id is a built-in spring type effect used for autocenter
         */

        error = pidff_request_effect_upload(pidff, 1);
        if (error) {
                hid_err(pidff->hid, "upload request failed\n");
                return error;
        }

        if (pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0] ==
            pidff->block_load[PID_EFFECT_BLOCK_INDEX].field->logical_minimum + 1) {
                pidff_autocenter(pidff, 0xffff);
                set_bit(FF_AUTOCENTER, dev->ffbit);
        } else {
                hid_notice(pidff->hid,
                           "device has unknown autocenter control method\n");
        }

        pidff_erase_pid(pidff,
                        pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0]);

        return 0;

}

/*
 * Check if the device is PID and initialize it
 */
int hid_pidff_init(struct hid_device *hid)
{
        struct pidff_device *pidff;
        struct hid_input *hidinput = list_entry(hid->inputs.next,
                                                struct hid_input, list);
        struct input_dev *dev = hidinput->input;
        struct ff_device *ff;
        int max_effects;
        int error;

        hid_dbg(hid, "starting pid init\n");

        if (list_empty(&hid->report_enum[HID_OUTPUT_REPORT].report_list)) {
                hid_dbg(hid, "not a PID device, no output report\n");
                return -ENODEV;
        }

        pidff = kzalloc(sizeof(*pidff), GFP_KERNEL);
        if (!pidff)
                return -ENOMEM;

        pidff->hid = hid;

        pidff_find_reports(hid, HID_OUTPUT_REPORT, pidff);
        pidff_find_reports(hid, HID_FEATURE_REPORT, pidff);

        if (!pidff_reports_ok(pidff)) {
                hid_dbg(hid, "reports not ok, aborting\n");
                error = -ENODEV;
                goto fail;
        }

        error = pidff_init_fields(pidff, dev);
        if (error)
                goto fail;

        pidff_reset(pidff);

        if (test_bit(FF_GAIN, dev->ffbit)) {
                pidff_set(&pidff->device_gain[PID_DEVICE_GAIN_FIELD], 0xffff);
                usbhid_submit_report(hid, pidff->reports[PID_DEVICE_GAIN],
                                     USB_DIR_OUT);
        }

        error = pidff_check_autocenter(pidff, dev);
        if (error)
                goto fail;

        max_effects =
            pidff->block_load[PID_EFFECT_BLOCK_INDEX].field->logical_maximum -
            pidff->block_load[PID_EFFECT_BLOCK_INDEX].field->logical_minimum +
            1;
        hid_dbg(hid, "max effects is %d\n", max_effects);

        if (max_effects > PID_EFFECTS_MAX)
                max_effects = PID_EFFECTS_MAX;

        if (pidff->pool[PID_SIMULTANEOUS_MAX].value)
                hid_dbg(hid, "max simultaneous effects is %d\n",
                        pidff->pool[PID_SIMULTANEOUS_MAX].value[0]);

        if (pidff->pool[PID_RAM_POOL_SIZE].value)
                hid_dbg(hid, "device memory size is %d bytes\n",
                        pidff->pool[PID_RAM_POOL_SIZE].value[0]);

        if (pidff->pool[PID_DEVICE_MANAGED_POOL].value &&
            pidff->pool[PID_DEVICE_MANAGED_POOL].value[0] == 0) {
                hid_notice(hid,
                           "device does not support device managed pool\n");
                goto fail;
        }

        error = input_ff_create(dev, max_effects);
        if (error)
                goto fail;

        ff = dev->ff;
        ff->private = pidff;
        ff->upload = pidff_upload_effect;
        ff->erase = pidff_erase_effect;
        ff->set_gain = pidff_set_gain;
        ff->set_autocenter = pidff_set_autocenter;
        ff->playback = pidff_playback;

        hid_info(dev, "Force feedback for USB HID PID devices by Anssi Hannula <anssi.hannula@gmail.com>\n");

        return 0;

 fail:
        kfree(pidff);
        return error;
}