// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ON pin driver for Dialog DA9052 PMICs
 *
 * Copyright(c) 2012 Dialog Semiconductor Ltd.
 *
 * Author: David Dajun Chen <dchen@diasemi.com>
 */

#include <linux/input.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>

#include <linux/mfd/da9052/da9052.h>
#include <linux/mfd/da9052/reg.h>

struct da9052_onkey {
        struct da9052 *da9052;
        struct input_dev *input;
        struct delayed_work work;
};

static void da9052_onkey_query(struct da9052_onkey *onkey)
{
        int ret;

        ret = da9052_reg_read(onkey->da9052, DA9052_STATUS_A_REG);
        if (ret < 0) {
                dev_err(onkey->da9052->dev,
                        "Failed to read onkey event err=%d\n", ret);
        } else {
                /*
                 * Since interrupt for deassertion of ONKEY pin is not
                 * generated, onkey event state determines the onkey
                 * button state.
                 */
                bool pressed = !(ret & DA9052_STATUSA_NONKEY);

                input_report_key(onkey->input, KEY_POWER, pressed);
                input_sync(onkey->input);

                /*
                 * Interrupt is generated only when the ONKEY pin
                 * is asserted.  Hence the deassertion of the pin
                 * is simulated through work queue.
                 */
                if (pressed)
                        schedule_delayed_work(&onkey->work,
                                                msecs_to_jiffies(50));
        }
}

static void da9052_onkey_work(struct work_struct *work)
{
        struct da9052_onkey *onkey = container_of(work, struct da9052_onkey,
                                                  work.work);

        da9052_onkey_query(onkey);
}

static irqreturn_t da9052_onkey_irq(int irq, void *data)
{
        struct da9052_onkey *onkey = data;

        da9052_onkey_query(onkey);

        return IRQ_HANDLED;
}

static int da9052_onkey_probe(struct platform_device *pdev)
{
        struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
        struct da9052_onkey *onkey;
        struct input_dev *input_dev;
        int error;

        if (!da9052) {
                dev_err(&pdev->dev, "Failed to get the driver's data\n");
                return -EINVAL;
        }

        onkey = kzalloc_obj(*onkey);
        input_dev = input_allocate_device();
        if (!onkey || !input_dev) {
                dev_err(&pdev->dev, "Failed to allocate memory\n");
                error = -ENOMEM;
                goto err_free_mem;
        }

        onkey->input = input_dev;
        onkey->da9052 = da9052;
        INIT_DELAYED_WORK(&onkey->work, da9052_onkey_work);

        input_dev->name = "da9052-onkey";
        input_dev->phys = "da9052-onkey/input0";
        input_dev->dev.parent = &pdev->dev;

        input_dev->evbit[0] = BIT_MASK(EV_KEY);
        __set_bit(KEY_POWER, input_dev->keybit);

        error = da9052_request_irq(onkey->da9052, DA9052_IRQ_NONKEY, "ONKEY",
                            da9052_onkey_irq, onkey);
        if (error < 0) {
                dev_err(onkey->da9052->dev,
                        "Failed to register ONKEY IRQ: %d\n", error);
                goto err_free_mem;
        }

        error = input_register_device(onkey->input);
        if (error) {
                dev_err(&pdev->dev, "Unable to register input device, %d\n",
                        error);
                goto err_free_irq;
        }

        platform_set_drvdata(pdev, onkey);
        return 0;

err_free_irq:
        da9052_free_irq(onkey->da9052, DA9052_IRQ_NONKEY, onkey);
        cancel_delayed_work_sync(&onkey->work);
err_free_mem:
        input_free_device(input_dev);
        kfree(onkey);

        return error;
}

static void da9052_onkey_remove(struct platform_device *pdev)
{
        struct da9052_onkey *onkey = platform_get_drvdata(pdev);

        da9052_free_irq(onkey->da9052, DA9052_IRQ_NONKEY, onkey);
        cancel_delayed_work_sync(&onkey->work);

        input_unregister_device(onkey->input);
        kfree(onkey);
}

static struct platform_driver da9052_onkey_driver = {
        .probe  = da9052_onkey_probe,
        .remove = da9052_onkey_remove,
        .driver = {
                .name   = "da9052-onkey",
        },
};
module_platform_driver(da9052_onkey_driver);

MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
MODULE_DESCRIPTION("Onkey driver for DA9052");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9052-onkey");