// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2024 NXP.
 */

#include <linux/input.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/scmi_protocol.h>
#include <linux/scmi_imx_protocol.h>
#include <linux/suspend.h>

#define DEBOUNCE_TIME           30
#define REPEAT_INTERVAL         60

struct scmi_imx_bbm {
        struct scmi_protocol_handle *ph;
        const struct scmi_imx_bbm_proto_ops *ops;
        struct notifier_block nb;
        int keycode;
        int keystate;  /* 1:pressed */
        bool suspended;
        struct delayed_work check_work;
        struct input_dev *input;
};

static void scmi_imx_bbm_pwrkey_check_for_events(struct work_struct *work)
{
        struct scmi_imx_bbm *bbnsm = container_of(to_delayed_work(work),
                                                  struct scmi_imx_bbm, check_work);
        struct scmi_protocol_handle *ph = bbnsm->ph;
        struct input_dev *input = bbnsm->input;
        u32 state = 0;
        int ret;

        ret = bbnsm->ops->button_get(ph, &state);
        if (ret) {
                pr_err("%s: %d\n", __func__, ret);
                return;
        }

        pr_debug("%s: state: %d, keystate %d\n", __func__, state, bbnsm->keystate);

        /* only report new event if status changed */
        if (state ^ bbnsm->keystate) {
                bbnsm->keystate = state;
                input_event(input, EV_KEY, bbnsm->keycode, state);
                input_sync(input);
                pm_relax(bbnsm->input->dev.parent);
                pr_debug("EV_KEY: %x\n", bbnsm->keycode);
        }

        /* repeat check if pressed long */
        if (state)
                schedule_delayed_work(&bbnsm->check_work, msecs_to_jiffies(REPEAT_INTERVAL));
}

static int scmi_imx_bbm_pwrkey_event(struct scmi_imx_bbm *bbnsm)
{
        struct input_dev *input = bbnsm->input;

        pm_wakeup_event(input->dev.parent, 0);

        /*
         * Directly report key event after resume to make no key press
         * event is missed.
         */
        if (READ_ONCE(bbnsm->suspended)) {
                bbnsm->keystate = 1;
                input_event(input, EV_KEY, bbnsm->keycode, 1);
                input_sync(input);
                WRITE_ONCE(bbnsm->suspended, false);
        }

        schedule_delayed_work(&bbnsm->check_work, msecs_to_jiffies(DEBOUNCE_TIME));

        return 0;
}

static void scmi_imx_bbm_pwrkey_act(void *pdata)
{
        struct scmi_imx_bbm *bbnsm = pdata;

        cancel_delayed_work_sync(&bbnsm->check_work);
}

static int scmi_imx_bbm_key_notifier(struct notifier_block *nb, unsigned long event, void *data)
{
        struct scmi_imx_bbm *bbnsm = container_of(nb, struct scmi_imx_bbm, nb);
        struct scmi_imx_bbm_notif_report *r = data;

        if (r->is_button) {
                pr_debug("BBM Button Power key pressed\n");
                scmi_imx_bbm_pwrkey_event(bbnsm);
        } else {
                /* Should never reach here */
                pr_err("Unexpected BBM event: %s\n", __func__);
        }

        return 0;
}

static int scmi_imx_bbm_pwrkey_init(struct scmi_device *sdev)
{
        const struct scmi_handle *handle = sdev->handle;
        struct device *dev = &sdev->dev;
        struct scmi_imx_bbm *bbnsm = dev_get_drvdata(dev);
        struct input_dev *input;
        int ret;

        if (device_property_read_u32(dev, "linux,code", &bbnsm->keycode)) {
                bbnsm->keycode = KEY_POWER;
                dev_warn(dev, "key code is not specified, using default KEY_POWER\n");
        }

        INIT_DELAYED_WORK(&bbnsm->check_work, scmi_imx_bbm_pwrkey_check_for_events);

        input = devm_input_allocate_device(dev);
        if (!input) {
                dev_err(dev, "failed to allocate the input device for SCMI IMX BBM\n");
                return -ENOMEM;
        }

        input->name = dev_name(dev);
        input->phys = "bbnsm-pwrkey/input0";
        input->id.bustype = BUS_HOST;

        input_set_capability(input, EV_KEY, bbnsm->keycode);

        ret = devm_add_action_or_reset(dev, scmi_imx_bbm_pwrkey_act, bbnsm);
        if (ret) {
                dev_err(dev, "failed to register remove action\n");
                return ret;
        }

        bbnsm->input = input;

        bbnsm->nb.notifier_call = &scmi_imx_bbm_key_notifier;
        ret = handle->notify_ops->devm_event_notifier_register(sdev, SCMI_PROTOCOL_IMX_BBM,
                                                               SCMI_EVENT_IMX_BBM_BUTTON,
                                                               NULL, &bbnsm->nb);

        if (ret)
                dev_err(dev, "Failed to register BBM Button Events %d:", ret);

        ret = input_register_device(input);
        if (ret) {
                dev_err(dev, "failed to register input device\n");
                return ret;
        }

        return 0;
}

static int scmi_imx_bbm_key_probe(struct scmi_device *sdev)
{
        const struct scmi_handle *handle = sdev->handle;
        struct device *dev = &sdev->dev;
        struct scmi_protocol_handle *ph;
        struct scmi_imx_bbm *bbnsm;
        int ret;

        if (!handle)
                return -ENODEV;

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

        bbnsm->ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_IMX_BBM, &ph);
        if (IS_ERR(bbnsm->ops))
                return PTR_ERR(bbnsm->ops);

        bbnsm->ph = ph;

        device_init_wakeup(dev, true);

        dev_set_drvdata(dev, bbnsm);

        ret = scmi_imx_bbm_pwrkey_init(sdev);
        if (ret)
                device_init_wakeup(dev, false);

        return ret;
}

static int __maybe_unused scmi_imx_bbm_key_suspend(struct device *dev)
{
        struct scmi_imx_bbm *bbnsm = dev_get_drvdata(dev);

        WRITE_ONCE(bbnsm->suspended, true);

        return 0;
}

static int __maybe_unused scmi_imx_bbm_key_resume(struct device *dev)
{
        return 0;
}

static SIMPLE_DEV_PM_OPS(scmi_imx_bbm_pm_key_ops, scmi_imx_bbm_key_suspend,
                         scmi_imx_bbm_key_resume);

static const struct scmi_device_id scmi_id_table[] = {
        { SCMI_PROTOCOL_IMX_BBM, "imx-bbm-key" },
        { },
};
MODULE_DEVICE_TABLE(scmi, scmi_id_table);

static struct scmi_driver scmi_imx_bbm_key_driver = {
        .driver = {
                .pm = &scmi_imx_bbm_pm_key_ops,
        },
        .name = "scmi-imx-bbm-key",
        .probe = scmi_imx_bbm_key_probe,
        .id_table = scmi_id_table,
};
module_scmi_driver(scmi_imx_bbm_key_driver);

MODULE_AUTHOR("Peng Fan <peng.fan@nxp.com>");
MODULE_DESCRIPTION("IMX SM BBM Key driver");
MODULE_LICENSE("GPL");