// SPDX-License-Identifier: GPL-2.0
/*
 * cros_ec_sensors - Driver for Chrome OS Embedded Controller sensors.
 *
 * Copyright (C) 2016 Google, Inc
 *
 * This driver uses the cros-ec interface to communicate with the Chrome OS
 * EC about sensors data. Data access is presented through iio sysfs.
 */

#include <linux/device.h>
#include <linux/iio/buffer.h>
#include <linux/iio/common/cros_ec_sensors_core.h>
#include <linux/iio/iio.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define CROS_EC_SENSORS_MAX_CHANNELS 4

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

        struct iio_chan_spec channels[CROS_EC_SENSORS_MAX_CHANNELS];
};

static int cros_ec_sensors_read(struct iio_dev *indio_dev,
                          struct iio_chan_spec const *chan,
                          int *val, int *val2, long mask)
{
        struct cros_ec_sensors_state *st = iio_priv(indio_dev);
        s16 data = 0;
        s64 val64;
        int i;
        int ret;
        int idx = chan->scan_index;

        mutex_lock(&st->core.cmd_lock);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = st->core.read_ec_sensors_data(indio_dev, 1 << idx, &data);
                if (ret < 0)
                        break;
                ret = IIO_VAL_INT;
                *val = data;
                break;
        case IIO_CHAN_INFO_CALIBBIAS:
                st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
                st->core.param.sensor_offset.flags = 0;

                ret = cros_ec_motion_send_host_cmd(&st->core, 0);
                if (ret < 0)
                        break;

                /* Save values */
                for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
                        st->core.calib[i].offset =
                                st->core.resp->sensor_offset.offset[i];
                ret = IIO_VAL_INT;
                *val = st->core.calib[idx].offset;
                break;
        case IIO_CHAN_INFO_CALIBSCALE:
                st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
                st->core.param.sensor_offset.flags = 0;

                ret = cros_ec_motion_send_host_cmd(&st->core, 0);
                if (ret == -EPROTO || ret == -EOPNOTSUPP) {
                        /* Reading calibscale is not supported on older EC. */
                        *val = 1;
                        *val2 = 0;
                        ret = IIO_VAL_INT_PLUS_MICRO;
                        break;
                } else if (ret) {
                        break;
                }

                /* Save values */
                for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
                        st->core.calib[i].scale =
                                st->core.resp->sensor_scale.scale[i];

                *val = st->core.calib[idx].scale >> 15;
                *val2 = ((st->core.calib[idx].scale & 0x7FFF) * 1000000LL) /
                        MOTION_SENSE_DEFAULT_SCALE;
                ret = IIO_VAL_INT_PLUS_MICRO;
                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;

                ret = cros_ec_motion_send_host_cmd(&st->core, 0);
                if (ret < 0)
                        break;

                val64 = st->core.resp->sensor_range.ret;
                switch (st->core.type) {
                case MOTIONSENSE_TYPE_ACCEL:
                        /*
                         * EC returns data in g, iio exepects m/s^2.
                         * Do not use IIO_G_TO_M_S_2 to avoid precision loss.
                         */
                        *val = div_s64(val64 * 980665, 10);
                        *val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
                        ret = IIO_VAL_FRACTIONAL;
                        break;
                case MOTIONSENSE_TYPE_GYRO:
                        /*
                         * EC returns data in dps, iio expects rad/s.
                         * Do not use IIO_DEGREE_TO_RAD to avoid precision
                         * loss. Round to the nearest integer.
                         */
                        *val = 0;
                        *val2 = div_s64(val64 * 3141592653ULL,
                                        180 << (CROS_EC_SENSOR_BITS - 1));
                        ret = IIO_VAL_INT_PLUS_NANO;
                        break;
                case MOTIONSENSE_TYPE_MAG:
                        /*
                         * EC returns data in 16LSB / uT,
                         * iio expects Gauss
                         */
                        *val = val64;
                        *val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
                        ret = IIO_VAL_FRACTIONAL;
                        break;
                default:
                        ret = -EINVAL;
                }
                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_sensors_write(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val, int val2, long mask)
{
        struct cros_ec_sensors_state *st = iio_priv(indio_dev);
        int i;
        int ret;
        int idx = chan->scan_index;

        mutex_lock(&st->core.cmd_lock);

        switch (mask) {
        case IIO_CHAN_INFO_CALIBBIAS:
                st->core.calib[idx].offset = val;

                /* Send to EC for each axis, even if not complete */
                st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
                st->core.param.sensor_offset.flags =
                        MOTION_SENSE_SET_OFFSET;
                for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
                        st->core.param.sensor_offset.offset[i] =
                                st->core.calib[i].offset;
                st->core.param.sensor_offset.temp =
                        EC_MOTION_SENSE_INVALID_CALIB_TEMP;

                ret = cros_ec_motion_send_host_cmd(&st->core, 0);
                break;
        case IIO_CHAN_INFO_CALIBSCALE:
                st->core.calib[idx].scale = val;
                /* Send to EC for each axis, even if not complete */

                st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
                st->core.param.sensor_offset.flags =
                        MOTION_SENSE_SET_OFFSET;
                for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
                        st->core.param.sensor_scale.scale[i] =
                                st->core.calib[i].scale;
                st->core.param.sensor_scale.temp =
                        EC_MOTION_SENSE_INVALID_CALIB_TEMP;

                ret = cros_ec_motion_send_host_cmd(&st->core, 0);
                break;
        case IIO_CHAN_INFO_SCALE:
                if (st->core.type == MOTIONSENSE_TYPE_MAG) {
                        ret = -EINVAL;
                        break;
                }
                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;

                ret = cros_ec_motion_send_host_cmd(&st->core, 0);
                if (ret == 0) {
                        st->core.range_updated = true;
                        st->core.curr_range = val;
                }
                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 ec_sensors_info = {
        .read_raw = &cros_ec_sensors_read,
        .write_raw = &cros_ec_sensors_write,
        .read_avail = &cros_ec_sensors_core_read_avail,
};

static int cros_ec_sensors_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct iio_dev *indio_dev;
        struct cros_ec_sensors_state *state;
        struct iio_chan_spec *channel;
        int ret, i;

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

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

        indio_dev->info = &ec_sensors_info;
        state = iio_priv(indio_dev);
        for (channel = state->channels, i = CROS_EC_SENSOR_X;
             i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
                /* Common part */
                channel->info_mask_separate =
                        BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_CALIBBIAS) |
                        BIT(IIO_CHAN_INFO_CALIBSCALE);
                channel->info_mask_shared_by_all =
                        BIT(IIO_CHAN_INFO_SCALE) |
                        BIT(IIO_CHAN_INFO_SAMP_FREQ);
                channel->info_mask_shared_by_all_available =
                        BIT(IIO_CHAN_INFO_SAMP_FREQ);
                channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
                channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
                channel->scan_index = i;
                channel->ext_info = cros_ec_sensors_ext_info;
                channel->modified = 1;
                channel->channel2 = IIO_MOD_X + i;
                channel->scan_type.sign = 's';

                /* Sensor specific */
                switch (state->core.type) {
                case MOTIONSENSE_TYPE_ACCEL:
                        channel->type = IIO_ACCEL;
                        break;
                case MOTIONSENSE_TYPE_GYRO:
                        channel->type = IIO_ANGL_VEL;
                        break;
                case MOTIONSENSE_TYPE_MAG:
                        channel->type = IIO_MAGN;
                        break;
                default:
                        dev_err(&pdev->dev, "Unknown motion sensor\n");
                        return -EINVAL;
                }
        }

        /* Timestamp */
        channel->type = IIO_TIMESTAMP;
        channel->channel = -1;
        channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
        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_SENSORS_MAX_CHANNELS;

        /* There is only enough room for accel and gyro in the io space */
        if ((state->core.ec->cmd_readmem != NULL) &&
            (state->core.type != MOTIONSENSE_TYPE_MAG))
                state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
        else
                state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;

        return cros_ec_sensors_core_register(dev, indio_dev,
                        cros_ec_sensors_push_data);
}

static const struct platform_device_id cros_ec_sensors_ids[] = {
        {
                .name = "cros-ec-accel",
        },
        {
                .name = "cros-ec-gyro",
        },
        {
                .name = "cros-ec-mag",
        },
        { }
};
MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);

static struct platform_driver cros_ec_sensors_platform_driver = {
        .driver = {
                .name   = "cros-ec-sensors",
                .pm     = &cros_ec_sensors_pm_ops,
        },
        .probe          = cros_ec_sensors_probe,
        .id_table       = cros_ec_sensors_ids,
};
module_platform_driver(cros_ec_sensors_platform_driver);

MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
MODULE_LICENSE("GPL v2");