// SPDX-License-Identifier: GPL-2.0
/*
 * Sensor HUB driver that discovers sensors behind a ChromeOS Embedded
 * Controller.
 *
 * Copyright 2019 Google LLC
 */

#include <linux/init.h>
#include <linux/device.h>
#include <linux/delay.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_data/cros_ec_sensorhub.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>

#define DRV_NAME                "cros-ec-sensorhub"
#define CROS_EC_CMD_INFO_RETRIES 50

static void cros_ec_sensorhub_free_sensor(void *arg)
{
        struct platform_device *pdev = arg;

        platform_device_unregister(pdev);
}

static int cros_ec_sensorhub_allocate_sensor(struct device *parent,
                                             char *sensor_name,
                                             int sensor_num)
{
        struct cros_ec_sensor_platform sensor_platforms = {
                .sensor_num = sensor_num,
        };
        struct platform_device *pdev;

        pdev = platform_device_register_data(parent, sensor_name,
                                             PLATFORM_DEVID_AUTO,
                                             &sensor_platforms,
                                             sizeof(sensor_platforms));
        if (IS_ERR(pdev))
                return PTR_ERR(pdev);

        return devm_add_action_or_reset(parent,
                                        cros_ec_sensorhub_free_sensor,
                                        pdev);
}

static int cros_ec_sensorhub_register(struct device *dev,
                                      struct cros_ec_sensorhub *sensorhub)
{
        int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
        struct cros_ec_command *msg = sensorhub->msg;
        struct cros_ec_dev *ec = sensorhub->ec;
        int ret, i, retries;
        char *name;


        msg->version = 1;
        msg->insize = sizeof(struct ec_response_motion_sense);
        msg->outsize = sizeof(struct ec_params_motion_sense);

        for (i = 0; i < sensorhub->sensor_num; i++) {
                sensorhub->params->cmd = MOTIONSENSE_CMD_INFO;
                sensorhub->params->info.sensor_num = i;

                retries = CROS_EC_CMD_INFO_RETRIES;
                do {
                        ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
                        if (ret == -EBUSY) {
                                /* The EC is still busy initializing sensors. */
                                usleep_range(5000, 6000);
                                retries--;
                        }
                } while (ret == -EBUSY && retries);

                if (ret < 0) {
                        dev_err(dev, "no info for EC sensor %d : %d/%d\n",
                                i, ret, msg->result);
                        continue;
                }
                if (retries < CROS_EC_CMD_INFO_RETRIES) {
                        dev_warn(dev, "%d retries needed to bring up sensor %d\n",
                                 CROS_EC_CMD_INFO_RETRIES - retries, i);
                }

                switch (sensorhub->resp->info.type) {
                case MOTIONSENSE_TYPE_ACCEL:
                        name = "cros-ec-accel";
                        break;
                case MOTIONSENSE_TYPE_BARO:
                        name = "cros-ec-baro";
                        break;
                case MOTIONSENSE_TYPE_GYRO:
                        name = "cros-ec-gyro";
                        break;
                case MOTIONSENSE_TYPE_MAG:
                        name = "cros-ec-mag";
                        break;
                case MOTIONSENSE_TYPE_PROX:
                        name = "cros-ec-prox";
                        break;
                case MOTIONSENSE_TYPE_LIGHT:
                        name = "cros-ec-light";
                        break;
                case MOTIONSENSE_TYPE_ACTIVITY:
                        name = "cros-ec-activity";
                        break;
                default:
                        dev_warn(dev, "unknown type %d\n",
                                 sensorhub->resp->info.type);
                        continue;
                }

                ret = cros_ec_sensorhub_allocate_sensor(dev, name, i);
                if (ret)
                        return ret;

                sensor_type[sensorhub->resp->info.type]++;
        }

        if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
                ec->has_kb_wake_angle = true;

        if (cros_ec_check_features(ec,
                                   EC_FEATURE_REFINED_TABLET_MODE_HYSTERESIS)) {
                ret = cros_ec_sensorhub_allocate_sensor(dev,
                                                        "cros-ec-lid-angle",
                                                        0);
                if (ret)
                        return ret;
        }

        return 0;
}

static int cros_ec_sensorhub_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
        struct cros_ec_sensorhub *data;
        struct cros_ec_command *msg;
        int ret, i, sensor_num;

        msg = devm_kzalloc(dev, sizeof(struct cros_ec_command) +
                           max((u16)sizeof(struct ec_params_motion_sense),
                               ec->ec_dev->max_response), GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;

        data = devm_kzalloc(dev, sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        mutex_init(&data->cmd_lock);

        data->dev = dev;
        data->ec = ec;
        data->msg = msg;
        data->params = (struct ec_params_motion_sense *)msg->data;
        data->resp = (struct ec_response_motion_sense *)msg->data;

        dev_set_drvdata(dev, data);

        /* Check whether this EC is a sensor hub. */
        if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE)) {
                sensor_num = cros_ec_get_sensor_count(ec);
                if (sensor_num < 0) {
                        dev_err(dev,
                                "Unable to retrieve sensor information (err:%d)\n",
                                sensor_num);
                        return sensor_num;
                }
                if (sensor_num == 0) {
                        dev_err(dev, "Zero sensors reported.\n");
                        return -EINVAL;
                }
                data->sensor_num = sensor_num;

                /*
                 * Prepare the ring handler before enumering the
                 * sensors.
                 */
                if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
                        ret = cros_ec_sensorhub_ring_allocate(data);
                        if (ret)
                                return ret;
                }

                /* Enumerate the sensors.*/
                ret = cros_ec_sensorhub_register(dev, data);
                if (ret)
                        return ret;

                /*
                 * When the EC does not have a FIFO, the sensors will query
                 * their data themselves via sysfs or a software trigger.
                 */
                if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
                        ret = cros_ec_sensorhub_ring_add(data);
                        if (ret)
                                return ret;
                        /*
                         * The msg and its data is not under the control of the
                         * ring handler.
                         */
                        return devm_add_action_or_reset(dev,
                                        cros_ec_sensorhub_ring_remove,
                                        data);
                }

        } else {
                /*
                 * If the device has sensors but does not claim to
                 * be a sensor hub, we are in legacy mode.
                 */
                data->sensor_num = 2;
                for (i = 0; i < data->sensor_num; i++) {
                        ret = cros_ec_sensorhub_allocate_sensor(dev,
                                                "cros-ec-accel-legacy", i);
                        if (ret)
                                return ret;
                }
        }


        return 0;
}

#ifdef CONFIG_PM_SLEEP
/*
 * When the EC is suspending, we must stop sending interrupt,
 * we may use the same interrupt line for waking up the device.
 * Tell the EC to stop sending non-interrupt event on the iio ring.
 */
static int cros_ec_sensorhub_suspend(struct device *dev)
{
        struct cros_ec_sensorhub *sensorhub = dev_get_drvdata(dev);
        struct cros_ec_dev *ec = sensorhub->ec;

        if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
                return cros_ec_sensorhub_ring_fifo_enable(sensorhub, false);
        return 0;
}

static int cros_ec_sensorhub_resume(struct device *dev)
{
        struct cros_ec_sensorhub *sensorhub = dev_get_drvdata(dev);
        struct cros_ec_dev *ec = sensorhub->ec;

        if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
                return cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(cros_ec_sensorhub_pm_ops,
                cros_ec_sensorhub_suspend,
                cros_ec_sensorhub_resume);

static const struct platform_device_id cros_ec_sensorhub_id[] = {
        { DRV_NAME, 0 },
        {}
};
MODULE_DEVICE_TABLE(platform, cros_ec_sensorhub_id);

static struct platform_driver cros_ec_sensorhub_driver = {
        .driver = {
                .name = DRV_NAME,
                .pm = &cros_ec_sensorhub_pm_ops,
        },
        .probe = cros_ec_sensorhub_probe,
        .id_table = cros_ec_sensorhub_id,
};

module_platform_driver(cros_ec_sensorhub_driver);

MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
MODULE_DESCRIPTION("ChromeOS EC MEMS Sensor Hub Driver");
MODULE_LICENSE("GPL");