// SPDX-License-Identifier: GPL-2.0+
//
// Copyright 2022 NXP.

#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeirq.h>
#include <linux/regmap.h>

#define BBNSM_CTRL              0x8
#define BBNSM_INT_EN            0x10
#define BBNSM_EVENTS            0x14
#define BBNSM_PAD_CTRL          0x24

#define BBNSM_BTN_PRESSED       BIT(7)
#define BBNSM_PWR_ON            BIT(6)
#define BBNSM_BTN_OFF           BIT(5)
#define BBNSM_EMG_OFF           BIT(4)
#define BBNSM_PWRKEY_EVENTS     (BBNSM_PWR_ON | BBNSM_BTN_OFF | BBNSM_EMG_OFF)
#define BBNSM_DP_EN             BIT(24)

#define DEBOUNCE_TIME           30
#define REPEAT_INTERVAL         60

struct bbnsm_pwrkey {
        struct regmap *regmap;
        int irq;
        int keycode;
        int keystate;  /* 1:pressed */
        bool suspended;
        struct timer_list check_timer;
        struct input_dev *input;
};

static void bbnsm_pwrkey_check_for_events(struct timer_list *t)
{
        struct bbnsm_pwrkey *bbnsm = timer_container_of(bbnsm, t, check_timer);
        struct input_dev *input = bbnsm->input;
        u32 state;

        regmap_read(bbnsm->regmap, BBNSM_EVENTS, &state);

        state = state & BBNSM_BTN_PRESSED ? 1 : 0;

        /* 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);
        }

        /* repeat check if pressed long */
        if (state)
                mod_timer(&bbnsm->check_timer,
                          jiffies + msecs_to_jiffies(REPEAT_INTERVAL));
}

static irqreturn_t bbnsm_pwrkey_interrupt(int irq, void *dev_id)
{
        struct platform_device *pdev = dev_id;
        struct bbnsm_pwrkey *bbnsm = platform_get_drvdata(pdev);
        struct input_dev *input = bbnsm->input;
        u32 event;

        regmap_read(bbnsm->regmap, BBNSM_EVENTS, &event);
        if (!(event & BBNSM_BTN_OFF))
                return IRQ_NONE;

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

        /*
         * Directly report key event after resume to make sure key press
         * event is never missed.
         */
        if (bbnsm->suspended) {
                bbnsm->keystate = 1;
                input_event(input, EV_KEY, bbnsm->keycode, 1);
                input_sync(input);
                /* Fire at most once per suspend/resume cycle */
                bbnsm->suspended = false;
        }

        mod_timer(&bbnsm->check_timer,
                   jiffies + msecs_to_jiffies(DEBOUNCE_TIME));

        /* clear PWR OFF */
        regmap_write(bbnsm->regmap, BBNSM_EVENTS, BBNSM_BTN_OFF);

        return IRQ_HANDLED;
}

static void bbnsm_pwrkey_act(void *pdata)
{
        struct bbnsm_pwrkey *bbnsm = pdata;

        timer_shutdown_sync(&bbnsm->check_timer);
}

static int bbnsm_pwrkey_probe(struct platform_device *pdev)
{
        struct bbnsm_pwrkey *bbnsm;
        struct input_dev *input;
        struct device_node *np = pdev->dev.of_node;
        int error;

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

        bbnsm->regmap = syscon_node_to_regmap(np->parent);
        if (IS_ERR(bbnsm->regmap)) {
                dev_err(&pdev->dev, "bbnsm pwerkey get regmap failed\n");
                return PTR_ERR(bbnsm->regmap);
        }

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

        bbnsm->irq = platform_get_irq(pdev, 0);
        if (bbnsm->irq < 0)
                return -EINVAL;

        /* config the BBNSM power related register */
        regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, BBNSM_DP_EN, BBNSM_DP_EN);

        /* clear the unexpected interrupt before driver ready */
        regmap_write_bits(bbnsm->regmap, BBNSM_EVENTS, BBNSM_PWRKEY_EVENTS,
                          BBNSM_PWRKEY_EVENTS);

        timer_setup(&bbnsm->check_timer, bbnsm_pwrkey_check_for_events, 0);

        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 = "bbnsm-pwrkey/input0";
        input->id.bustype = BUS_HOST;

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

        /* input customer action to cancel release timer */
        error = devm_add_action(&pdev->dev, bbnsm_pwrkey_act, bbnsm);
        if (error) {
                dev_err(&pdev->dev, "failed to register remove action\n");
                return error;
        }

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

        error = devm_request_irq(&pdev->dev, bbnsm->irq, bbnsm_pwrkey_interrupt,
                                 IRQF_SHARED, pdev->name, pdev);
        if (error) {
                dev_err(&pdev->dev, "interrupt not available.\n");
                return error;
        }

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

        device_init_wakeup(&pdev->dev, true);
        error = dev_pm_set_wake_irq(&pdev->dev, bbnsm->irq);
        if (error)
                dev_warn(&pdev->dev, "irq wake enable failed.\n");

        return 0;
}

static void bbnsm_pwrkey_remove(struct platform_device *pdev)
{
        dev_pm_clear_wake_irq(&pdev->dev);
        device_init_wakeup(&pdev->dev, false);
}

static int __maybe_unused bbnsm_pwrkey_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct bbnsm_pwrkey *bbnsm = platform_get_drvdata(pdev);

        bbnsm->suspended = true;

        return 0;
}

static int __maybe_unused bbnsm_pwrkey_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct bbnsm_pwrkey *bbnsm = platform_get_drvdata(pdev);

        bbnsm->suspended = false;

        return 0;
}

static SIMPLE_DEV_PM_OPS(bbnsm_pwrkey_pm_ops, bbnsm_pwrkey_suspend,
                bbnsm_pwrkey_resume);

static const struct of_device_id bbnsm_pwrkey_ids[] = {
        { .compatible = "nxp,imx93-bbnsm-pwrkey" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, bbnsm_pwrkey_ids);

static struct platform_driver bbnsm_pwrkey_driver = {
        .driver = {
                .name = "bbnsm_pwrkey",
                .pm = &bbnsm_pwrkey_pm_ops,
                .of_match_table = bbnsm_pwrkey_ids,
        },
        .probe = bbnsm_pwrkey_probe,
        .remove = bbnsm_pwrkey_remove,

};
module_platform_driver(bbnsm_pwrkey_driver);

MODULE_AUTHOR("Jacky Bai <ping.bai@nxp.com>");
MODULE_DESCRIPTION("NXP bbnsm power key Driver");
MODULE_LICENSE("GPL");