// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
 *
 * Copyright (C) 2014 Google, Inc.
 */

#include <linux/dmi.h>
#include <linux/kconfig.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/platform_data/cros_ec_chardev.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/slab.h>

#define DRV_NAME "cros-ec-dev"

static struct class cros_class = {
        .owner          = THIS_MODULE,
        .name           = "chromeos",
};

/**
 * struct cros_feature_to_name - CrOS feature id to name/short description.
 * @id: The feature identifier.
 * @name: Device name associated with the feature id.
 * @desc: Short name that will be displayed.
 */
struct cros_feature_to_name {
        unsigned int id;
        const char *name;
        const char *desc;
};

/**
 * struct cros_feature_to_cells - CrOS feature id to mfd cells association.
 * @id: The feature identifier.
 * @mfd_cells: Pointer to the array of mfd cells that needs to be added.
 * @num_cells: Number of mfd cells into the array.
 */
struct cros_feature_to_cells {
        unsigned int id;
        const struct mfd_cell *mfd_cells;
        unsigned int num_cells;
};

static const struct cros_feature_to_name cros_mcu_devices[] = {
        {
                .id     = EC_FEATURE_FINGERPRINT,
                .name   = CROS_EC_DEV_FP_NAME,
                .desc   = "Fingerprint",
        },
        {
                .id     = EC_FEATURE_ISH,
                .name   = CROS_EC_DEV_ISH_NAME,
                .desc   = "Integrated Sensor Hub",
        },
        {
                .id     = EC_FEATURE_SCP,
                .name   = CROS_EC_DEV_SCP_NAME,
                .desc   = "System Control Processor",
        },
        {
                .id     = EC_FEATURE_TOUCHPAD,
                .name   = CROS_EC_DEV_TP_NAME,
                .desc   = "Touchpad",
        },
};

static const struct mfd_cell cros_ec_cec_cells[] = {
        { .name = "cros-ec-cec", },
};

static const struct mfd_cell cros_ec_rtc_cells[] = {
        { .name = "cros-ec-rtc", },
};

static const struct mfd_cell cros_ec_sensorhub_cells[] = {
        { .name = "cros-ec-sensorhub", },
};

static const struct mfd_cell cros_usbpd_charger_cells[] = {
        { .name = "cros-usbpd-charger", },
        { .name = "cros-usbpd-logger", },
};

static const struct mfd_cell cros_usbpd_notify_cells[] = {
        { .name = "cros-usbpd-notify", },
};

static const struct cros_feature_to_cells cros_subdevices[] = {
        {
                .id             = EC_FEATURE_CEC,
                .mfd_cells      = cros_ec_cec_cells,
                .num_cells      = ARRAY_SIZE(cros_ec_cec_cells),
        },
        {
                .id             = EC_FEATURE_RTC,
                .mfd_cells      = cros_ec_rtc_cells,
                .num_cells      = ARRAY_SIZE(cros_ec_rtc_cells),
        },
        {
                .id             = EC_FEATURE_USB_PD,
                .mfd_cells      = cros_usbpd_charger_cells,
                .num_cells      = ARRAY_SIZE(cros_usbpd_charger_cells),
        },
};

static const struct mfd_cell cros_ec_platform_cells[] = {
        { .name = "cros-ec-chardev", },
        { .name = "cros-ec-debugfs", },
        { .name = "cros-ec-sysfs", },
        { .name = "cros-ec-pchg", },
};

static const struct mfd_cell cros_ec_lightbar_cells[] = {
        { .name = "cros-ec-lightbar", }
};

static const struct mfd_cell cros_ec_vbc_cells[] = {
        { .name = "cros-ec-vbc", }
};

static void cros_ec_class_release(struct device *dev)
{
        kfree(to_cros_ec_dev(dev));
}

static int ec_device_probe(struct platform_device *pdev)
{
        int retval = -ENOMEM;
        struct device_node *node;
        struct device *dev = &pdev->dev;
        struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
        struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
        int i;

        if (!ec)
                return retval;

        dev_set_drvdata(dev, ec);
        ec->ec_dev = dev_get_drvdata(dev->parent);
        ec->dev = dev;
        ec->cmd_offset = ec_platform->cmd_offset;
        ec->features[0] = -1U; /* Not cached yet */
        ec->features[1] = -1U; /* Not cached yet */
        device_initialize(&ec->class_dev);

        for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
                /*
                 * Check whether this is actually a dedicated MCU rather
                 * than an standard EC.
                 */
                if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
                        dev_info(dev, "CrOS %s MCU detected\n",
                                 cros_mcu_devices[i].desc);
                        /*
                         * Help userspace differentiating ECs from other MCU,
                         * regardless of the probing order.
                         */
                        ec_platform->ec_name = cros_mcu_devices[i].name;
                        break;
                }
        }

        /*
         * Add the class device
         */
        ec->class_dev.class = &cros_class;
        ec->class_dev.parent = dev;
        ec->class_dev.release = cros_ec_class_release;

        retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
        if (retval) {
                dev_err(dev, "dev_set_name failed => %d\n", retval);
                goto failed;
        }

        retval = device_add(&ec->class_dev);
        if (retval)
                goto failed;

        /* check whether this EC is a sensor hub. */
        if (cros_ec_get_sensor_count(ec) > 0) {
                retval = mfd_add_hotplug_devices(ec->dev,
                                cros_ec_sensorhub_cells,
                                ARRAY_SIZE(cros_ec_sensorhub_cells));
                if (retval)
                        dev_err(ec->dev, "failed to add %s subdevice: %d\n",
                                cros_ec_sensorhub_cells->name, retval);
        }

        /*
         * The following subdevices can be detected by sending the
         * EC_FEATURE_GET_CMD Embedded Controller device.
         */
        for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
                if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
                        retval = mfd_add_hotplug_devices(ec->dev,
                                                cros_subdevices[i].mfd_cells,
                                                cros_subdevices[i].num_cells);
                        if (retval)
                                dev_err(ec->dev,
                                        "failed to add %s subdevice: %d\n",
                                        cros_subdevices[i].mfd_cells->name,
                                        retval);
                }
        }

        /*
         * Lightbar is a special case. Newer devices support autodetection,
         * but older ones do not.
         */
        if (cros_ec_check_features(ec, EC_FEATURE_LIGHTBAR) ||
            dmi_match(DMI_PRODUCT_NAME, "Link")) {
                retval = mfd_add_hotplug_devices(ec->dev,
                                        cros_ec_lightbar_cells,
                                        ARRAY_SIZE(cros_ec_lightbar_cells));
                if (retval)
                        dev_warn(ec->dev, "failed to add lightbar: %d\n",
                                 retval);
        }

        /*
         * The PD notifier driver cell is separate since it only needs to be
         * explicitly added on platforms that don't have the PD notifier ACPI
         * device entry defined.
         */
        if (IS_ENABLED(CONFIG_OF) && ec->ec_dev->dev->of_node) {
                if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
                        retval = mfd_add_hotplug_devices(ec->dev,
                                        cros_usbpd_notify_cells,
                                        ARRAY_SIZE(cros_usbpd_notify_cells));
                        if (retval)
                                dev_err(ec->dev,
                                        "failed to add PD notify devices: %d\n",
                                        retval);
                }
        }

        /*
         * The following subdevices cannot be detected by sending the
         * EC_FEATURE_GET_CMD to the Embedded Controller device.
         */
        retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
                                         ARRAY_SIZE(cros_ec_platform_cells));
        if (retval)
                dev_warn(ec->dev,
                         "failed to add cros-ec platform devices: %d\n",
                         retval);

        /* Check whether this EC instance has a VBC NVRAM */
        node = ec->ec_dev->dev->of_node;
        if (of_property_read_bool(node, "google,has-vbc-nvram")) {
                retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
                                                ARRAY_SIZE(cros_ec_vbc_cells));
                if (retval)
                        dev_warn(ec->dev, "failed to add VBC devices: %d\n",
                                 retval);
        }

        return 0;

failed:
        put_device(&ec->class_dev);
        return retval;
}

static int ec_device_remove(struct platform_device *pdev)
{
        struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);

        mfd_remove_devices(ec->dev);
        device_unregister(&ec->class_dev);
        return 0;
}

static const struct platform_device_id cros_ec_id[] = {
        { DRV_NAME, 0 },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, cros_ec_id);

static struct platform_driver cros_ec_dev_driver = {
        .driver = {
                .name = DRV_NAME,
        },
        .id_table = cros_ec_id,
        .probe = ec_device_probe,
        .remove = ec_device_remove,
};

static int __init cros_ec_dev_init(void)
{
        int ret;

        ret  = class_register(&cros_class);
        if (ret) {
                pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
                return ret;
        }

        /* Register the driver */
        ret = platform_driver_register(&cros_ec_dev_driver);
        if (ret < 0) {
                pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
                goto failed_devreg;
        }
        return 0;

failed_devreg:
        class_unregister(&cros_class);
        return ret;
}

static void __exit cros_ec_dev_exit(void)
{
        platform_driver_unregister(&cros_ec_dev_driver);
        class_unregister(&cros_class);
}

module_init(cros_ec_dev_init);
module_exit(cros_ec_dev_exit);

MODULE_ALIAS("platform:" DRV_NAME);
MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
MODULE_VERSION("1.0");
MODULE_LICENSE("GPL");