/*
 *  Copyright (C) 2014, Samsung Electronics Co. Ltd. All Rights Reserved.
 *
 *  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.
 *
 */

#include <linux/iio/iio.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/of_platform.h>
#include "ssp.h"

#define SSP_WDT_TIME                    10000
#define SSP_LIMIT_RESET_CNT             20
#define SSP_LIMIT_TIMEOUT_CNT           3

/* It is possible that it is max clk rate for version 1.0 of bootcode */
#define SSP_BOOT_SPI_HZ 400000

/*
 * These fields can look enigmatic but this structure is used mainly to flat
 * some values and depends on command type.
 */
struct ssp_instruction {
        __le32 a;
        __le32 b;
        u8 c;
} __attribute__((__packed__));

static const u8 ssp_magnitude_table[] = {110, 85, 171, 71, 203, 195, 0, 67,
        208, 56, 175, 244, 206, 213, 0, 92, 250, 0, 55, 48, 189, 252, 171,
        243, 13, 45, 250};

static const struct ssp_sensorhub_info ssp_rinato_info = {
        .fw_name = "ssp_B2.fw",
        .fw_crashed_name = "ssp_crashed.fw",
        .fw_rev = 14052300,
        .mag_table = ssp_magnitude_table,
        .mag_length = ARRAY_SIZE(ssp_magnitude_table),
};

static const struct ssp_sensorhub_info ssp_thermostat_info = {
        .fw_name = "thermostat_B2.fw",
        .fw_crashed_name = "ssp_crashed.fw",
        .fw_rev = 14080600,
        .mag_table = ssp_magnitude_table,
        .mag_length = ARRAY_SIZE(ssp_magnitude_table),
};

static const struct mfd_cell sensorhub_sensor_devs[] = {
        {
                .name = "ssp-accelerometer",
        },
        {
                .name = "ssp-gyroscope",
        },
};

static void ssp_toggle_mcu_reset_gpio(struct ssp_data *data)
{
        gpio_set_value(data->mcu_reset_gpio, 0);
        usleep_range(1000, 1200);
        gpio_set_value(data->mcu_reset_gpio, 1);
        msleep(50);
}

static void ssp_sync_available_sensors(struct ssp_data *data)
{
        int i, ret;

        for (i = 0; i < SSP_SENSOR_MAX; ++i) {
                if (data->available_sensors & BIT(i)) {
                        ret = ssp_enable_sensor(data, i, data->delay_buf[i]);
                        if (ret < 0) {
                                dev_err(&data->spi->dev,
                                        "Sync sensor nr: %d fail\n", i);
                                continue;
                        }
                }
        }

        ret = ssp_command(data, SSP_MSG2SSP_AP_MCU_SET_DUMPMODE,
                          data->mcu_dump_mode);
        if (ret < 0)
                dev_err(&data->spi->dev,
                        "SSP_MSG2SSP_AP_MCU_SET_DUMPMODE failed\n");
}

static void ssp_enable_mcu(struct ssp_data *data, bool enable)
{
        dev_info(&data->spi->dev, "current shutdown = %d, old = %d\n", enable,
                 data->shut_down);

        if (enable && data->shut_down) {
                data->shut_down = false;
                enable_irq(data->spi->irq);
                enable_irq_wake(data->spi->irq);
        } else if (!enable && !data->shut_down) {
                data->shut_down = true;
                disable_irq(data->spi->irq);
                disable_irq_wake(data->spi->irq);
        } else {
                dev_warn(&data->spi->dev, "current shutdown = %d, old = %d\n",
                         enable, data->shut_down);
        }
}

/*
 * This function is the first one which communicates with the mcu so it is
 * possible that the first attempt will fail
 */
static int ssp_check_fwbl(struct ssp_data *data)
{
        int retries = 0;

        while (retries++ < 5) {
                data->cur_firm_rev = ssp_get_firmware_rev(data);
                if (data->cur_firm_rev == SSP_INVALID_REVISION ||
                    data->cur_firm_rev == SSP_INVALID_REVISION2) {
                        dev_warn(&data->spi->dev,
                                 "Invalid revision, trying %d time\n", retries);
                } else {
                        break;
                }
        }

        if (data->cur_firm_rev == SSP_INVALID_REVISION ||
            data->cur_firm_rev == SSP_INVALID_REVISION2) {
                dev_err(&data->spi->dev, "SSP_INVALID_REVISION\n");
                return SSP_FW_DL_STATE_NEED_TO_SCHEDULE;
        }

        dev_info(&data->spi->dev,
                 "MCU Firm Rev : Old = %8u, New = %8u\n",
                 data->cur_firm_rev,
                 data->sensorhub_info->fw_rev);

        if (data->cur_firm_rev != data->sensorhub_info->fw_rev)
                return SSP_FW_DL_STATE_NEED_TO_SCHEDULE;

        return SSP_FW_DL_STATE_NONE;
}

static void ssp_reset_mcu(struct ssp_data *data)
{
        ssp_enable_mcu(data, false);
        ssp_clean_pending_list(data);
        ssp_toggle_mcu_reset_gpio(data);
        ssp_enable_mcu(data, true);
}

static void ssp_wdt_work_func(struct work_struct *work)
{
        struct ssp_data *data = container_of(work, struct ssp_data, work_wdt);

        dev_err(&data->spi->dev, "%s - Sensor state: 0x%x, RC: %u, CC: %u\n",
                __func__, data->available_sensors, data->reset_cnt,
                data->com_fail_cnt);

        ssp_reset_mcu(data);
        data->com_fail_cnt = 0;
        data->timeout_cnt = 0;
}

static void ssp_wdt_timer_func(struct timer_list *t)
{
        struct ssp_data *data = from_timer(data, t, wdt_timer);

        switch (data->fw_dl_state) {
        case SSP_FW_DL_STATE_FAIL:
        case SSP_FW_DL_STATE_DOWNLOADING:
        case SSP_FW_DL_STATE_SYNC:
                goto _mod;
        }

        if (data->timeout_cnt > SSP_LIMIT_TIMEOUT_CNT ||
            data->com_fail_cnt > SSP_LIMIT_RESET_CNT)
                queue_work(system_power_efficient_wq, &data->work_wdt);
_mod:
        mod_timer(&data->wdt_timer, jiffies + msecs_to_jiffies(SSP_WDT_TIME));
}

static void ssp_enable_wdt_timer(struct ssp_data *data)
{
        mod_timer(&data->wdt_timer, jiffies + msecs_to_jiffies(SSP_WDT_TIME));
}

static void ssp_disable_wdt_timer(struct ssp_data *data)
{
        del_timer_sync(&data->wdt_timer);
        cancel_work_sync(&data->work_wdt);
}

/**
 * ssp_get_sensor_delay() - gets sensor data acquisition period
 * @data:       sensorhub structure
 * @type:       SSP sensor type
 *
 * Returns acquisition period in ms
 */
u32 ssp_get_sensor_delay(struct ssp_data *data, enum ssp_sensor_type type)
{
        return data->delay_buf[type];
}
EXPORT_SYMBOL(ssp_get_sensor_delay);

/**
 * ssp_enable_sensor() - enables data acquisition for sensor
 * @data:       sensorhub structure
 * @type:       SSP sensor type
 * @delay:      delay in ms
 *
 * Returns 0 or negative value in case of error
 */
int ssp_enable_sensor(struct ssp_data *data, enum ssp_sensor_type type,
                      u32 delay)
{
        int ret;
        struct ssp_instruction to_send;

        to_send.a = cpu_to_le32(delay);
        to_send.b = cpu_to_le32(data->batch_latency_buf[type]);
        to_send.c = data->batch_opt_buf[type];

        switch (data->check_status[type]) {
        case SSP_INITIALIZATION_STATE:
                /* do calibration step, now just enable */
        case SSP_ADD_SENSOR_STATE:
                ret = ssp_send_instruction(data,
                                           SSP_MSG2SSP_INST_BYPASS_SENSOR_ADD,
                                           type,
                                           (u8 *)&to_send, sizeof(to_send));
                if (ret < 0) {
                        dev_err(&data->spi->dev, "Enabling sensor failed\n");
                        data->check_status[type] = SSP_NO_SENSOR_STATE;
                        goto derror;
                }

                data->sensor_enable |= BIT(type);
                data->check_status[type] = SSP_RUNNING_SENSOR_STATE;
                break;
        case SSP_RUNNING_SENSOR_STATE:
                ret = ssp_send_instruction(data,
                                           SSP_MSG2SSP_INST_CHANGE_DELAY, type,
                                           (u8 *)&to_send, sizeof(to_send));
                if (ret < 0) {
                        dev_err(&data->spi->dev,
                                "Changing sensor delay failed\n");
                        goto derror;
                }
                break;
        default:
                data->check_status[type] = SSP_ADD_SENSOR_STATE;
                break;
        }

        data->delay_buf[type] = delay;

        if (atomic_inc_return(&data->enable_refcount) == 1)
                ssp_enable_wdt_timer(data);

        return 0;

derror:
        return ret;
}
EXPORT_SYMBOL(ssp_enable_sensor);

/**
 * ssp_change_delay() - changes data acquisition for sensor
 * @data:       sensorhub structure
 * @type:       SSP sensor type
 * @delay:      delay in ms
 *
 * Returns 0 or negative value in case of error
 */
int ssp_change_delay(struct ssp_data *data, enum ssp_sensor_type type,
                     u32 delay)
{
        int ret;
        struct ssp_instruction to_send;

        to_send.a = cpu_to_le32(delay);
        to_send.b = cpu_to_le32(data->batch_latency_buf[type]);
        to_send.c = data->batch_opt_buf[type];

        ret = ssp_send_instruction(data, SSP_MSG2SSP_INST_CHANGE_DELAY, type,
                                   (u8 *)&to_send, sizeof(to_send));
        if (ret < 0) {
                dev_err(&data->spi->dev, "Changing sensor delay failed\n");
                return ret;
        }

        data->delay_buf[type] = delay;

        return 0;
}
EXPORT_SYMBOL(ssp_change_delay);

/**
 * ssp_disable_sensor() - disables sensor
 *
 * @data:       sensorhub structure
 * @type:       SSP sensor type
 *
 * Returns 0 or negative value in case of error
 */
int ssp_disable_sensor(struct ssp_data *data, enum ssp_sensor_type type)
{
        int ret;
        __le32 command;

        if (data->sensor_enable & BIT(type)) {
                command = cpu_to_le32(data->delay_buf[type]);

                ret = ssp_send_instruction(data,
                                           SSP_MSG2SSP_INST_BYPASS_SENSOR_RM,
                                           type, (u8 *)&command,
                                           sizeof(command));
                if (ret < 0) {
                        dev_err(&data->spi->dev, "Remove sensor fail\n");
                        return ret;
                }

                data->sensor_enable &= ~BIT(type);
        }

        data->check_status[type] = SSP_ADD_SENSOR_STATE;

        if (atomic_dec_and_test(&data->enable_refcount))
                ssp_disable_wdt_timer(data);

        return 0;
}
EXPORT_SYMBOL(ssp_disable_sensor);

static irqreturn_t ssp_irq_thread_fn(int irq, void *dev_id)
{
        struct ssp_data *data = dev_id;

        /*
         * This wrapper is done to preserve error path for ssp_irq_msg, also
         * it is defined in different file.
         */
        ssp_irq_msg(data);

        return IRQ_HANDLED;
}

static int ssp_initialize_mcu(struct ssp_data *data)
{
        int ret;

        ssp_clean_pending_list(data);

        ret = ssp_get_chipid(data);
        if (ret != SSP_DEVICE_ID) {
                dev_err(&data->spi->dev, "%s - MCU %s ret = %d\n", __func__,
                        ret < 0 ? "is not working" : "identification failed",
                        ret);
                return ret < 0 ? ret : -ENODEV;
        }

        dev_info(&data->spi->dev, "MCU device ID = %d\n", ret);

        /*
         * needs clarification, for now do not want to export all transfer
         * methods to sensors' drivers
         */
        ret = ssp_set_magnetic_matrix(data);
        if (ret < 0) {
                dev_err(&data->spi->dev,
                        "%s - ssp_set_magnetic_matrix failed\n", __func__);
                return ret;
        }

        data->available_sensors = ssp_get_sensor_scanning_info(data);
        if (data->available_sensors == 0) {
                dev_err(&data->spi->dev,
                        "%s - ssp_get_sensor_scanning_info failed\n", __func__);
                return -EIO;
        }

        data->cur_firm_rev = ssp_get_firmware_rev(data);
        dev_info(&data->spi->dev, "MCU Firm Rev : New = %8u\n",
                 data->cur_firm_rev);

        return ssp_command(data, SSP_MSG2SSP_AP_MCU_DUMP_CHECK, 0);
}

/*
 * sensorhub can request its reinitialization as some brutal and rare error
 * handling. It can be requested from the MCU.
 */
static void ssp_refresh_task(struct work_struct *work)
{
        struct ssp_data *data = container_of((struct delayed_work *)work,
                                             struct ssp_data, work_refresh);

        dev_info(&data->spi->dev, "refreshing\n");

        data->reset_cnt++;

        if (ssp_initialize_mcu(data) >= 0) {
                ssp_sync_available_sensors(data);
                if (data->last_ap_state != 0)
                        ssp_command(data, data->last_ap_state, 0);

                if (data->last_resume_state != 0)
                        ssp_command(data, data->last_resume_state, 0);

                data->timeout_cnt = 0;
                data->com_fail_cnt = 0;
        }
}

int ssp_queue_ssp_refresh_task(struct ssp_data *data, unsigned int delay)
{
        cancel_delayed_work_sync(&data->work_refresh);

        return queue_delayed_work(system_power_efficient_wq,
                                  &data->work_refresh,
                                  msecs_to_jiffies(delay));
}

#ifdef CONFIG_OF
static const struct of_device_id ssp_of_match[] = {
        {
                .compatible     = "samsung,sensorhub-rinato",
                .data           = &ssp_rinato_info,
        }, {
                .compatible     = "samsung,sensorhub-thermostat",
                .data           = &ssp_thermostat_info,
        },
        {},
};
MODULE_DEVICE_TABLE(of, ssp_of_match);

static struct ssp_data *ssp_parse_dt(struct device *dev)
{
        int ret;
        struct ssp_data *data;
        struct device_node *node = dev->of_node;
        const struct of_device_id *match;

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

        data->mcu_ap_gpio = of_get_named_gpio(node, "mcu-ap-gpios", 0);
        if (data->mcu_ap_gpio < 0)
                goto err_free_pd;

        data->ap_mcu_gpio = of_get_named_gpio(node, "ap-mcu-gpios", 0);
        if (data->ap_mcu_gpio < 0)
                goto err_free_pd;

        data->mcu_reset_gpio = of_get_named_gpio(node, "mcu-reset-gpios", 0);
        if (data->mcu_reset_gpio < 0)
                goto err_free_pd;

        ret = devm_gpio_request_one(dev, data->ap_mcu_gpio, GPIOF_OUT_INIT_HIGH,
                                    "ap-mcu-gpios");
        if (ret)
                goto err_free_pd;

        ret = devm_gpio_request_one(dev, data->mcu_reset_gpio,
                                    GPIOF_OUT_INIT_HIGH, "mcu-reset-gpios");
        if (ret)
                goto err_ap_mcu;

        match = of_match_node(ssp_of_match, node);
        if (!match)
                goto err_mcu_reset_gpio;

        data->sensorhub_info = match->data;

        dev_set_drvdata(dev, data);

        return data;

err_mcu_reset_gpio:
        devm_gpio_free(dev, data->mcu_reset_gpio);
err_ap_mcu:
        devm_gpio_free(dev, data->ap_mcu_gpio);
err_free_pd:
        devm_kfree(dev, data);
        return NULL;
}
#else
static struct ssp_data *ssp_parse_dt(struct device *pdev)
{
        return NULL;
}
#endif

/**
 * ssp_register_consumer() - registers iio consumer in ssp framework
 *
 * @indio_dev:  consumer iio device
 * @type:       ssp sensor type
 */
void ssp_register_consumer(struct iio_dev *indio_dev, enum ssp_sensor_type type)
{
        struct ssp_data *data = dev_get_drvdata(indio_dev->dev.parent->parent);

        data->sensor_devs[type] = indio_dev;
}
EXPORT_SYMBOL(ssp_register_consumer);

static int ssp_probe(struct spi_device *spi)
{
        int ret, i;
        struct ssp_data *data;

        data = ssp_parse_dt(&spi->dev);
        if (!data) {
                dev_err(&spi->dev, "Failed to find platform data\n");
                return -ENODEV;
        }

        ret = mfd_add_devices(&spi->dev, -1, sensorhub_sensor_devs,
                              ARRAY_SIZE(sensorhub_sensor_devs), NULL, 0, NULL);
        if (ret < 0) {
                dev_err(&spi->dev, "mfd add devices fail\n");
                return ret;
        }

        spi->mode = SPI_MODE_1;
        ret = spi_setup(spi);
        if (ret < 0) {
                dev_err(&spi->dev, "Failed to setup spi\n");
                return ret;
        }

        data->fw_dl_state = SSP_FW_DL_STATE_NONE;
        data->spi = spi;
        spi_set_drvdata(spi, data);

        mutex_init(&data->comm_lock);

        for (i = 0; i < SSP_SENSOR_MAX; ++i) {
                data->delay_buf[i] = SSP_DEFAULT_POLLING_DELAY;
                data->batch_latency_buf[i] = 0;
                data->batch_opt_buf[i] = 0;
                data->check_status[i] = SSP_INITIALIZATION_STATE;
        }

        data->delay_buf[SSP_BIO_HRM_LIB] = 100;

        data->time_syncing = true;

        mutex_init(&data->pending_lock);
        INIT_LIST_HEAD(&data->pending_list);

        atomic_set(&data->enable_refcount, 0);

        INIT_WORK(&data->work_wdt, ssp_wdt_work_func);
        INIT_DELAYED_WORK(&data->work_refresh, ssp_refresh_task);

        timer_setup(&data->wdt_timer, ssp_wdt_timer_func, 0);

        ret = request_threaded_irq(data->spi->irq, NULL,
                                   ssp_irq_thread_fn,
                                   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                                   "SSP_Int", data);
        if (ret < 0) {
                dev_err(&spi->dev, "Irq request fail\n");
                goto err_setup_irq;
        }

        /* Let's start with enabled one so irq balance could be ok */
        data->shut_down = false;

        /* just to avoid unbalanced irq set wake up */
        enable_irq_wake(data->spi->irq);

        data->fw_dl_state = ssp_check_fwbl(data);
        if (data->fw_dl_state == SSP_FW_DL_STATE_NONE) {
                ret = ssp_initialize_mcu(data);
                if (ret < 0) {
                        dev_err(&spi->dev, "Initialize_mcu failed\n");
                        goto err_read_reg;
                }
        } else {
                dev_err(&spi->dev, "Firmware version not supported\n");
                ret = -EPERM;
                goto err_read_reg;
        }

        return 0;

err_read_reg:
        free_irq(data->spi->irq, data);
err_setup_irq:
        mutex_destroy(&data->pending_lock);
        mutex_destroy(&data->comm_lock);

        dev_err(&spi->dev, "Probe failed!\n");

        return ret;
}

static int ssp_remove(struct spi_device *spi)
{
        struct ssp_data *data = spi_get_drvdata(spi);

        if (ssp_command(data, SSP_MSG2SSP_AP_STATUS_SHUTDOWN, 0) < 0)
                dev_err(&data->spi->dev,
                        "SSP_MSG2SSP_AP_STATUS_SHUTDOWN failed\n");

        ssp_enable_mcu(data, false);
        ssp_disable_wdt_timer(data);

        ssp_clean_pending_list(data);

        free_irq(data->spi->irq, data);

        del_timer_sync(&data->wdt_timer);
        cancel_work_sync(&data->work_wdt);

        mutex_destroy(&data->comm_lock);
        mutex_destroy(&data->pending_lock);

        mfd_remove_devices(&spi->dev);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int ssp_suspend(struct device *dev)
{
        int ret;
        struct ssp_data *data = spi_get_drvdata(to_spi_device(dev));

        data->last_resume_state = SSP_MSG2SSP_AP_STATUS_SUSPEND;

        if (atomic_read(&data->enable_refcount) > 0)
                ssp_disable_wdt_timer(data);

        ret = ssp_command(data, SSP_MSG2SSP_AP_STATUS_SUSPEND, 0);
        if (ret < 0) {
                dev_err(&data->spi->dev,
                        "%s SSP_MSG2SSP_AP_STATUS_SUSPEND failed\n", __func__);

                ssp_enable_wdt_timer(data);
                return ret;
        }

        data->time_syncing = false;
        disable_irq(data->spi->irq);

        return 0;
}

static int ssp_resume(struct device *dev)
{
        int ret;
        struct ssp_data *data = spi_get_drvdata(to_spi_device(dev));

        enable_irq(data->spi->irq);

        if (atomic_read(&data->enable_refcount) > 0)
                ssp_enable_wdt_timer(data);

        ret = ssp_command(data, SSP_MSG2SSP_AP_STATUS_RESUME, 0);
        if (ret < 0) {
                dev_err(&data->spi->dev,
                        "%s SSP_MSG2SSP_AP_STATUS_RESUME failed\n", __func__);
                ssp_disable_wdt_timer(data);
                return ret;
        }

        /* timesyncing is set by MCU */
        data->last_resume_state = SSP_MSG2SSP_AP_STATUS_RESUME;

        return 0;
}
#endif /* CONFIG_PM_SLEEP */

static const struct dev_pm_ops ssp_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(ssp_suspend, ssp_resume)
};

static struct spi_driver ssp_driver = {
        .probe = ssp_probe,
        .remove = ssp_remove,
        .driver = {
                .pm = &ssp_pm_ops,
                .of_match_table = of_match_ptr(ssp_of_match),
                .name = "sensorhub"
        },
};

module_spi_driver(ssp_driver);

MODULE_DESCRIPTION("ssp sensorhub driver");
MODULE_AUTHOR("Samsung Electronics");
MODULE_LICENSE("GPL");