// SPDX-License-Identifier: GPL-2.0
// ChromeOS Embedded Controller extcon
//
// Copyright (C) 2017 Google, Inc.
// Author: Benson Leung <bleung@chromium.org>

#include <linux/extcon-provider.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/of.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>
#include <linux/sched.h>

struct cros_ec_extcon_info {
        struct device *dev;
        struct extcon_dev *edev;

        int port_id;

        struct cros_ec_device *ec;

        struct notifier_block notifier;

        unsigned int dr; /* data role */
        bool pr; /* power role (true if VBUS enabled) */
        bool dp; /* DisplayPort enabled */
        bool mux; /* SuperSpeed (usb3) enabled */
        unsigned int power_type;
};

static const unsigned int usb_type_c_cable[] = {
        EXTCON_USB,
        EXTCON_USB_HOST,
        EXTCON_DISP_DP,
        EXTCON_NONE,
};

enum usb_data_roles {
        DR_NONE,
        DR_HOST,
        DR_DEVICE,
};

/**
 * cros_ec_pd_command() - Send a command to the EC.
 * @info: pointer to struct cros_ec_extcon_info
 * @command: EC command
 * @version: EC command version
 * @outdata: EC command output data
 * @outsize: Size of outdata
 * @indata: EC command input data
 * @insize: Size of indata
 *
 * Return: 0 on success, <0 on failure.
 */
static int cros_ec_pd_command(struct cros_ec_extcon_info *info,
                              unsigned int command,
                              unsigned int version,
                              void *outdata,
                              unsigned int outsize,
                              void *indata,
                              unsigned int insize)
{
        struct cros_ec_command *msg;
        int ret;

        msg = kzalloc_flex(*msg, data, max(outsize, insize));
        if (!msg)
                return -ENOMEM;

        msg->version = version;
        msg->command = command;
        msg->outsize = outsize;
        msg->insize = insize;

        if (outsize)
                memcpy(msg->data, outdata, outsize);

        ret = cros_ec_cmd_xfer_status(info->ec, msg);
        if (ret >= 0 && insize)
                memcpy(indata, msg->data, insize);

        kfree(msg);
        return ret;
}

/**
 * cros_ec_usb_get_power_type() - Get power type info about PD device attached
 * to given port.
 * @info: pointer to struct cros_ec_extcon_info
 *
 * Return: power type on success, <0 on failure.
 */
static int cros_ec_usb_get_power_type(struct cros_ec_extcon_info *info)
{
        struct ec_params_usb_pd_power_info req;
        struct ec_response_usb_pd_power_info resp;
        int ret;

        req.port = info->port_id;
        ret = cros_ec_pd_command(info, EC_CMD_USB_PD_POWER_INFO, 0,
                                 &req, sizeof(req), &resp, sizeof(resp));
        if (ret < 0)
                return ret;

        return resp.type;
}

/**
 * cros_ec_usb_get_pd_mux_state() - Get PD mux state for given port.
 * @info: pointer to struct cros_ec_extcon_info
 *
 * Return: PD mux state on success, <0 on failure.
 */
static int cros_ec_usb_get_pd_mux_state(struct cros_ec_extcon_info *info)
{
        struct ec_params_usb_pd_mux_info req;
        struct ec_response_usb_pd_mux_info resp;
        int ret;

        req.port = info->port_id;
        ret = cros_ec_pd_command(info, EC_CMD_USB_PD_MUX_INFO, 0,
                                 &req, sizeof(req),
                                 &resp, sizeof(resp));
        if (ret < 0)
                return ret;

        return resp.flags;
}

/**
 * cros_ec_usb_get_role() - Get role info about possible PD device attached to a
 * given port.
 * @info: pointer to struct cros_ec_extcon_info
 * @polarity: pointer to cable polarity (return value)
 *
 * Return: role info on success, -ENOTCONN if no cable is connected, <0 on
 * failure.
 */
static int cros_ec_usb_get_role(struct cros_ec_extcon_info *info,
                                bool *polarity)
{
        struct ec_params_usb_pd_control pd_control;
        struct ec_response_usb_pd_control_v1 resp;
        int ret;

        pd_control.port = info->port_id;
        pd_control.role = USB_PD_CTRL_ROLE_NO_CHANGE;
        pd_control.mux = USB_PD_CTRL_MUX_NO_CHANGE;
        pd_control.swap = USB_PD_CTRL_SWAP_NONE;
        ret = cros_ec_pd_command(info, EC_CMD_USB_PD_CONTROL, 1,
                                 &pd_control, sizeof(pd_control),
                                 &resp, sizeof(resp));
        if (ret < 0)
                return ret;

        if (!(resp.enabled & PD_CTRL_RESP_ENABLED_CONNECTED))
                return -ENOTCONN;

        *polarity = resp.polarity;

        return resp.role;
}

/**
 * cros_ec_pd_get_num_ports() - Get number of EC charge ports.
 * @info: pointer to struct cros_ec_extcon_info
 *
 * Return: number of ports on success, <0 on failure.
 */
static int cros_ec_pd_get_num_ports(struct cros_ec_extcon_info *info)
{
        struct ec_response_usb_pd_ports resp;
        int ret;

        ret = cros_ec_pd_command(info, EC_CMD_USB_PD_PORTS,
                                 0, NULL, 0, &resp, sizeof(resp));
        if (ret < 0)
                return ret;

        return resp.num_ports;
}

static const char *cros_ec_usb_role_string(unsigned int role)
{
        return role == DR_NONE ? "DISCONNECTED" :
                (role == DR_HOST ? "DFP" : "UFP");
}

static const char *cros_ec_usb_power_type_string(unsigned int type)
{
        switch (type) {
        case USB_CHG_TYPE_NONE:
                return "USB_CHG_TYPE_NONE";
        case USB_CHG_TYPE_PD:
                return "USB_CHG_TYPE_PD";
        case USB_CHG_TYPE_PROPRIETARY:
                return "USB_CHG_TYPE_PROPRIETARY";
        case USB_CHG_TYPE_C:
                return "USB_CHG_TYPE_C";
        case USB_CHG_TYPE_BC12_DCP:
                return "USB_CHG_TYPE_BC12_DCP";
        case USB_CHG_TYPE_BC12_CDP:
                return "USB_CHG_TYPE_BC12_CDP";
        case USB_CHG_TYPE_BC12_SDP:
                return "USB_CHG_TYPE_BC12_SDP";
        case USB_CHG_TYPE_OTHER:
                return "USB_CHG_TYPE_OTHER";
        case USB_CHG_TYPE_VBUS:
                return "USB_CHG_TYPE_VBUS";
        case USB_CHG_TYPE_UNKNOWN:
                return "USB_CHG_TYPE_UNKNOWN";
        default:
                return "USB_CHG_TYPE_UNKNOWN";
        }
}

static bool cros_ec_usb_power_type_is_wall_wart(unsigned int type,
                                                unsigned int role)
{
        switch (type) {
        /* FIXME : Guppy, Donnettes, and other chargers will be miscategorized
         * because they identify with USB_CHG_TYPE_C, but we can't return true
         * here from that code because that breaks Suzy-Q and other kinds of
         * USB Type-C cables and peripherals.
         */
        case USB_CHG_TYPE_PROPRIETARY:
        case USB_CHG_TYPE_BC12_DCP:
                return true;
        case USB_CHG_TYPE_PD:
        case USB_CHG_TYPE_C:
        case USB_CHG_TYPE_BC12_CDP:
        case USB_CHG_TYPE_BC12_SDP:
        case USB_CHG_TYPE_OTHER:
        case USB_CHG_TYPE_VBUS:
        case USB_CHG_TYPE_UNKNOWN:
        case USB_CHG_TYPE_NONE:
        default:
                return false;
        }
}

static int extcon_cros_ec_detect_cable(struct cros_ec_extcon_info *info,
                                       bool force)
{
        struct device *dev = info->dev;
        int role, power_type;
        unsigned int dr = DR_NONE;
        bool pr = false;
        bool polarity = false;
        bool dp = false;
        bool mux = false;
        bool hpd = false;

        power_type = cros_ec_usb_get_power_type(info);
        if (power_type < 0) {
                dev_err(dev, "failed getting power type err = %d\n",
                        power_type);
                return power_type;
        }

        role = cros_ec_usb_get_role(info, &polarity);
        if (role < 0) {
                if (role != -ENOTCONN) {
                        dev_err(dev, "failed getting role err = %d\n", role);
                        return role;
                }
                dev_dbg(dev, "disconnected\n");
        } else {
                int pd_mux_state;

                dr = (role & PD_CTRL_RESP_ROLE_DATA) ? DR_HOST : DR_DEVICE;
                pr = (role & PD_CTRL_RESP_ROLE_POWER);
                pd_mux_state = cros_ec_usb_get_pd_mux_state(info);
                if (pd_mux_state < 0)
                        pd_mux_state = USB_PD_MUX_USB_ENABLED;

                dp = pd_mux_state & USB_PD_MUX_DP_ENABLED;
                mux = pd_mux_state & USB_PD_MUX_USB_ENABLED;
                hpd = pd_mux_state & USB_PD_MUX_HPD_IRQ;

                dev_dbg(dev,
                        "connected role 0x%x pwr type %d dr %d pr %d pol %d mux %d dp %d hpd %d\n",
                        role, power_type, dr, pr, polarity, mux, dp, hpd);
        }

        /*
         * When there is no USB host (e.g. USB PD charger),
         * we are not really a UFP for the AP.
         */
        if (dr == DR_DEVICE &&
            cros_ec_usb_power_type_is_wall_wart(power_type, role))
                dr = DR_NONE;

        if (force || info->dr != dr || info->pr != pr || info->dp != dp ||
            info->mux != mux || info->power_type != power_type) {
                bool host_connected = false, device_connected = false;

                dev_dbg(dev, "Type/Role switch! type = %s role = %s\n",
                        cros_ec_usb_power_type_string(power_type),
                        cros_ec_usb_role_string(dr));
                info->dr = dr;
                info->pr = pr;
                info->dp = dp;
                info->mux = mux;
                info->power_type = power_type;

                if (dr == DR_DEVICE)
                        device_connected = true;
                else if (dr == DR_HOST)
                        host_connected = true;

                extcon_set_state(info->edev, EXTCON_USB, device_connected);
                extcon_set_state(info->edev, EXTCON_USB_HOST, host_connected);
                extcon_set_state(info->edev, EXTCON_DISP_DP, dp);
                extcon_set_property(info->edev, EXTCON_USB,
                                    EXTCON_PROP_USB_VBUS,
                                    (union extcon_property_value)(int)pr);
                extcon_set_property(info->edev, EXTCON_USB_HOST,
                                    EXTCON_PROP_USB_VBUS,
                                    (union extcon_property_value)(int)pr);
                extcon_set_property(info->edev, EXTCON_USB,
                                    EXTCON_PROP_USB_TYPEC_POLARITY,
                                    (union extcon_property_value)(int)polarity);
                extcon_set_property(info->edev, EXTCON_USB_HOST,
                                    EXTCON_PROP_USB_TYPEC_POLARITY,
                                    (union extcon_property_value)(int)polarity);
                extcon_set_property(info->edev, EXTCON_DISP_DP,
                                    EXTCON_PROP_USB_TYPEC_POLARITY,
                                    (union extcon_property_value)(int)polarity);
                extcon_set_property(info->edev, EXTCON_USB,
                                    EXTCON_PROP_USB_SS,
                                    (union extcon_property_value)(int)mux);
                extcon_set_property(info->edev, EXTCON_USB_HOST,
                                    EXTCON_PROP_USB_SS,
                                    (union extcon_property_value)(int)mux);
                extcon_set_property(info->edev, EXTCON_DISP_DP,
                                    EXTCON_PROP_USB_SS,
                                    (union extcon_property_value)(int)mux);
                extcon_set_property(info->edev, EXTCON_DISP_DP,
                                    EXTCON_PROP_DISP_HPD,
                                    (union extcon_property_value)(int)hpd);

                extcon_sync(info->edev, EXTCON_USB);
                extcon_sync(info->edev, EXTCON_USB_HOST);
                extcon_sync(info->edev, EXTCON_DISP_DP);

        } else if (hpd) {
                extcon_set_property(info->edev, EXTCON_DISP_DP,
                                    EXTCON_PROP_DISP_HPD,
                                    (union extcon_property_value)(int)hpd);
                extcon_sync(info->edev, EXTCON_DISP_DP);
        }

        return 0;
}

static int extcon_cros_ec_event(struct notifier_block *nb,
                                unsigned long queued_during_suspend,
                                void *_notify)
{
        struct cros_ec_extcon_info *info;
        struct cros_ec_device *ec;
        u32 host_event;

        info = container_of(nb, struct cros_ec_extcon_info, notifier);
        ec = info->ec;

        host_event = cros_ec_get_host_event(ec);
        if (host_event & (EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU) |
                          EC_HOST_EVENT_MASK(EC_HOST_EVENT_USB_MUX))) {
                extcon_cros_ec_detect_cable(info, false);
                return NOTIFY_OK;
        }

        return NOTIFY_DONE;
}

static int extcon_cros_ec_probe(struct platform_device *pdev)
{
        struct cros_ec_extcon_info *info;
        struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        int numports, ret;

        info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        info->dev = dev;
        info->ec = ec;

        if (np) {
                u32 port;

                ret = of_property_read_u32(np, "google,usb-port-id", &port);
                if (ret < 0) {
                        dev_err(dev, "Missing google,usb-port-id property\n");
                        return ret;
                }
                info->port_id = port;
        } else {
                info->port_id = pdev->id;
        }

        numports = cros_ec_pd_get_num_ports(info);
        if (numports < 0) {
                dev_err(dev, "failed getting number of ports! ret = %d\n",
                        numports);
                return numports;
        }

        if (info->port_id >= numports) {
                dev_err(dev, "This system only supports %d ports\n", numports);
                return -ENODEV;
        }

        info->edev = devm_extcon_dev_allocate(dev, usb_type_c_cable);
        if (IS_ERR(info->edev)) {
                dev_err(dev, "failed to allocate extcon device\n");
                return -ENOMEM;
        }

        ret = devm_extcon_dev_register(dev, info->edev);
        if (ret < 0) {
                dev_err(dev, "failed to register extcon device\n");
                return ret;
        }

        extcon_set_property_capability(info->edev, EXTCON_USB,
                                       EXTCON_PROP_USB_VBUS);
        extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
                                       EXTCON_PROP_USB_VBUS);
        extcon_set_property_capability(info->edev, EXTCON_USB,
                                       EXTCON_PROP_USB_TYPEC_POLARITY);
        extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
                                       EXTCON_PROP_USB_TYPEC_POLARITY);
        extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
                                       EXTCON_PROP_USB_TYPEC_POLARITY);
        extcon_set_property_capability(info->edev, EXTCON_USB,
                                       EXTCON_PROP_USB_SS);
        extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
                                       EXTCON_PROP_USB_SS);
        extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
                                       EXTCON_PROP_USB_SS);
        extcon_set_property_capability(info->edev, EXTCON_DISP_DP,
                                       EXTCON_PROP_DISP_HPD);

        info->dr = DR_NONE;
        info->pr = false;

        platform_set_drvdata(pdev, info);

        /* Get PD events from the EC */
        info->notifier.notifier_call = extcon_cros_ec_event;
        ret = blocking_notifier_chain_register(&info->ec->event_notifier,
                                               &info->notifier);
        if (ret < 0) {
                dev_err(dev, "failed to register notifier\n");
                return ret;
        }

        /* Perform initial detection */
        ret = extcon_cros_ec_detect_cable(info, true);
        if (ret < 0) {
                dev_err(dev, "failed to detect initial cable state\n");
                goto unregister_notifier;
        }

        return 0;

unregister_notifier:
        blocking_notifier_chain_unregister(&info->ec->event_notifier,
                                           &info->notifier);
        return ret;
}

static void extcon_cros_ec_remove(struct platform_device *pdev)
{
        struct cros_ec_extcon_info *info = platform_get_drvdata(pdev);

        blocking_notifier_chain_unregister(&info->ec->event_notifier,
                                           &info->notifier);
}

#ifdef CONFIG_PM_SLEEP
static int extcon_cros_ec_suspend(struct device *dev)
{
        return 0;
}

static int extcon_cros_ec_resume(struct device *dev)
{
        int ret;
        struct cros_ec_extcon_info *info = dev_get_drvdata(dev);

        ret = extcon_cros_ec_detect_cable(info, true);
        if (ret < 0)
                dev_err(dev, "failed to detect cable state on resume\n");

        return 0;
}

static const struct dev_pm_ops extcon_cros_ec_dev_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(extcon_cros_ec_suspend, extcon_cros_ec_resume)
};

#define DEV_PM_OPS      (&extcon_cros_ec_dev_pm_ops)
#else
#define DEV_PM_OPS      NULL
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_OF
static const struct of_device_id extcon_cros_ec_of_match[] = {
        { .compatible = "google,extcon-usbc-cros-ec" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, extcon_cros_ec_of_match);
#endif /* CONFIG_OF */

static struct platform_driver extcon_cros_ec_driver = {
        .driver = {
                .name  = "extcon-usbc-cros-ec",
                .of_match_table = of_match_ptr(extcon_cros_ec_of_match),
                .pm = DEV_PM_OPS,
        },
        .remove  = extcon_cros_ec_remove,
        .probe   = extcon_cros_ec_probe,
};

module_platform_driver(extcon_cros_ec_driver);

MODULE_DESCRIPTION("ChromeOS Embedded Controller extcon driver");
MODULE_AUTHOR("Benson Leung <bleung@chromium.org>");
MODULE_LICENSE("GPL v2");