/*
 * cros_ec_baro - Driver for barometer sensor behind CrosEC.
 *
 * Copyright (C) 2017 Google, Inc
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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/delay.h>
#include <linux/device.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/kernel.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

#include "../common/cros_ec_sensors/cros_ec_sensors_core.h"

/*
 * One channel for pressure, the other for timestamp.
 */
#define CROS_EC_BARO_MAX_CHANNELS (1 + 1)

/* State data for ec_sensors iio driver. */
struct cros_ec_baro_state {
        /* Shared by all sensors */
        struct cros_ec_sensors_core_state core;

        struct iio_chan_spec channels[CROS_EC_BARO_MAX_CHANNELS];
};

static int cros_ec_baro_read(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int *val, int *val2, long mask)
{
        struct cros_ec_baro_state *st = iio_priv(indio_dev);
        u16 data = 0;
        int ret = IIO_VAL_INT;
        int idx = chan->scan_index;

        mutex_lock(&st->core.cmd_lock);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (cros_ec_sensors_read_cmd(indio_dev, 1 << idx,
                                             (s16 *)&data) < 0)
                        ret = -EIO;
                *val = data;
                break;
        case IIO_CHAN_INFO_SCALE:
                st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
                st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;

                if (cros_ec_motion_send_host_cmd(&st->core, 0)) {
                        ret = -EIO;
                        break;
                }
                *val = st->core.resp->sensor_range.ret;

                /* scale * in_pressure_raw --> kPa */
                *val2 = 10 << CROS_EC_SENSOR_BITS;
                ret = IIO_VAL_FRACTIONAL;
                break;
        default:
                ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
                                                mask);
                break;
        }

        mutex_unlock(&st->core.cmd_lock);

        return ret;
}

static int cros_ec_baro_write(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int val, int val2, long mask)
{
        struct cros_ec_baro_state *st = iio_priv(indio_dev);
        int ret = 0;

        mutex_lock(&st->core.cmd_lock);

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
                st->core.param.sensor_range.data = val;

                /* Always roundup, so caller gets at least what it asks for. */
                st->core.param.sensor_range.roundup = 1;

                if (cros_ec_motion_send_host_cmd(&st->core, 0))
                        ret = -EIO;
                break;
        default:
                ret = cros_ec_sensors_core_write(&st->core, chan, val, val2,
                                                 mask);
                break;
        }

        mutex_unlock(&st->core.cmd_lock);

        return ret;
}

static const struct iio_info cros_ec_baro_info = {
        .read_raw = &cros_ec_baro_read,
        .write_raw = &cros_ec_baro_write,
        .driver_module = THIS_MODULE,
};

static int cros_ec_baro_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
        struct cros_ec_device *ec_device;
        struct iio_dev *indio_dev;
        struct cros_ec_baro_state *state;
        struct iio_chan_spec *channel;
        int ret;

        if (!ec_dev || !ec_dev->ec_dev) {
                dev_warn(dev, "No CROS EC device found.\n");
                return -EINVAL;
        }
        ec_device = ec_dev->ec_dev;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
        if (!indio_dev)
                return -ENOMEM;

        ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
        if (ret)
                return ret;

        indio_dev->info = &cros_ec_baro_info;
        state = iio_priv(indio_dev);
        state->core.type = state->core.resp->info.type;
        state->core.loc = state->core.resp->info.location;
        channel = state->channels;
        /* Common part */
        channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
        channel->info_mask_shared_by_all =
                BIT(IIO_CHAN_INFO_SCALE) |
                BIT(IIO_CHAN_INFO_SAMP_FREQ) |
                BIT(IIO_CHAN_INFO_FREQUENCY);
        channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
        channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
        channel->scan_type.shift = 0;
        channel->scan_index = 0;
        channel->ext_info = cros_ec_sensors_ext_info;
        channel->scan_type.sign = 'u';

        state->core.calib[0] = 0;

        /* Sensor specific */
        switch (state->core.type) {
        case MOTIONSENSE_TYPE_BARO:
                channel->type = IIO_PRESSURE;
                break;
        default:
                dev_warn(dev, "Unknown motion sensor\n");
                return -EINVAL;
        }

        /* Timestamp */
        channel++;
        channel->type = IIO_TIMESTAMP;
        channel->channel = -1;
        channel->scan_index = 1;
        channel->scan_type.sign = 's';
        channel->scan_type.realbits = 64;
        channel->scan_type.storagebits = 64;

        indio_dev->channels = state->channels;
        indio_dev->num_channels = CROS_EC_BARO_MAX_CHANNELS;

        state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;

        ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
                                              cros_ec_sensors_capture, NULL);
        if (ret)
                return ret;

        return devm_iio_device_register(dev, indio_dev);
}

static const struct platform_device_id cros_ec_baro_ids[] = {
        {
                .name = "cros-ec-baro",
        },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, cros_ec_baro_ids);

static struct platform_driver cros_ec_baro_platform_driver = {
        .driver = {
                .name   = "cros-ec-baro",
        },
        .probe          = cros_ec_baro_probe,
        .id_table       = cros_ec_baro_ids,
};
module_platform_driver(cros_ec_baro_platform_driver);

MODULE_DESCRIPTION("ChromeOS EC barometer sensor driver");
MODULE_LICENSE("GPL v2");