// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2019 NXP.
 */

#include <linux/err.h>
#include <linux/device.h>
#include <linux/firmware/imx/sci.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/property.h>

#define DEBOUNCE_TIME                           30
#define REPEAT_INTERVAL                         60

#define SC_IRQ_BUTTON                           1
#define SC_IRQ_GROUP_WAKE                       3

#define IMX_SC_MISC_FUNC_GET_BUTTON_STATUS      18

struct imx_key_drv_data {
        u32 keycode;
        bool keystate;  /* true: pressed, false: released */
        struct delayed_work check_work;
        struct input_dev *input;
        struct imx_sc_ipc *key_ipc_handle;
        struct notifier_block key_notifier;
};

struct imx_sc_msg_key {
        struct imx_sc_rpc_msg hdr;
        u32 state;
};

static int imx_sc_key_notify(struct notifier_block *nb,
                             unsigned long event, void *group)
{
        struct imx_key_drv_data *priv =
                                 container_of(nb,
                                              struct imx_key_drv_data,
                                              key_notifier);

        if ((event & SC_IRQ_BUTTON) && (*(u8 *)group == SC_IRQ_GROUP_WAKE)) {
                schedule_delayed_work(&priv->check_work,
                                      msecs_to_jiffies(DEBOUNCE_TIME));
                pm_wakeup_event(priv->input->dev.parent, 0);
        }

        return 0;
}

static void imx_sc_check_for_events(struct work_struct *work)
{
        struct imx_key_drv_data *priv =
                                 container_of(work,
                                              struct imx_key_drv_data,
                                              check_work.work);
        struct input_dev *input = priv->input;
        struct imx_sc_msg_key msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;
        bool state;
        int error;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_MISC;
        hdr->func = IMX_SC_MISC_FUNC_GET_BUTTON_STATUS;
        hdr->size = 1;

        error = imx_scu_call_rpc(priv->key_ipc_handle, &msg, true);
        if (error) {
                dev_err(&input->dev, "read imx sc key failed, error %d\n", error);
                return;
        }

        /*
         * The response data from SCU firmware is 4 bytes,
         * but ONLY the first byte is the key state, other
         * 3 bytes could be some dirty data, so we should
         * ONLY take the first byte as key state.
         */
        state = (bool)(msg.state & 0xff);

        if (state ^ priv->keystate) {
                priv->keystate = state;
                input_event(input, EV_KEY, priv->keycode, state);
                input_sync(input);
                if (!priv->keystate)
                        pm_relax(priv->input->dev.parent);
        }

        if (state)
                schedule_delayed_work(&priv->check_work,
                                      msecs_to_jiffies(REPEAT_INTERVAL));
}

static void imx_sc_key_action(void *data)
{
        struct imx_key_drv_data *priv = data;

        imx_scu_irq_group_enable(SC_IRQ_GROUP_WAKE, SC_IRQ_BUTTON, false);
        imx_scu_irq_unregister_notifier(&priv->key_notifier);
        cancel_delayed_work_sync(&priv->check_work);
}

static int imx_sc_key_probe(struct platform_device *pdev)
{
        struct imx_key_drv_data *priv;
        struct input_dev *input;
        int error;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        error = imx_scu_get_handle(&priv->key_ipc_handle);
        if (error)
                return error;

        if (device_property_read_u32(&pdev->dev, "linux,keycodes",
                                     &priv->keycode)) {
                dev_err(&pdev->dev, "missing linux,keycodes property\n");
                return -EINVAL;
        }

        INIT_DELAYED_WORK(&priv->check_work, imx_sc_check_for_events);

        input = devm_input_allocate_device(&pdev->dev);
        if (!input) {
                dev_err(&pdev->dev, "failed to allocate the input device\n");
                return -ENOMEM;
        }

        input->name = pdev->name;
        input->phys = "imx-sc-key/input0";
        input->id.bustype = BUS_HOST;

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

        error = input_register_device(input);
        if (error) {
                dev_err(&pdev->dev, "failed to register input device\n");
                return error;
        }

        priv->input = input;
        platform_set_drvdata(pdev, priv);

        error = imx_scu_irq_group_enable(SC_IRQ_GROUP_WAKE, SC_IRQ_BUTTON,
                                         true);
        if (error) {
                dev_err(&pdev->dev, "failed to enable scu group irq\n");
                return error;
        }

        error = devm_add_action_or_reset(&pdev->dev, imx_sc_key_action, priv);
        if (error)
                return error;

        priv->key_notifier.notifier_call = imx_sc_key_notify;
        error = imx_scu_irq_register_notifier(&priv->key_notifier);
        if (error)
                dev_err(&pdev->dev, "failed to register scu notifier\n");

        return error;
}

static const struct of_device_id imx_sc_key_ids[] = {
        { .compatible = "fsl,imx-sc-key" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx_sc_key_ids);

static struct platform_driver imx_sc_key_driver = {
        .driver = {
                .name = "imx-sc-key",
                .of_match_table = imx_sc_key_ids,
        },
        .probe = imx_sc_key_probe,
};
module_platform_driver(imx_sc_key_driver);

MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
MODULE_DESCRIPTION("i.MX System Controller Key Driver");
MODULE_LICENSE("GPL v2");