// SPDX-License-Identifier: GPL-2.0-only
/*
 * Maxim Integrated MAX3355 USB OTG chip extcon driver
 *
 * Copyright (C)  2014-2015 Cogent Embedded, Inc.
 * Author: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
 */

#include <linux/extcon-provider.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>

struct max3355_data {
        struct extcon_dev *edev;
        struct gpio_desc *id_gpiod;
        struct gpio_desc *shdn_gpiod;
};

static const unsigned int max3355_cable[] = {
        EXTCON_USB,
        EXTCON_USB_HOST,
        EXTCON_NONE,
};

static irqreturn_t max3355_id_irq(int irq, void *dev_id)
{
        struct max3355_data *data = dev_id;
        int id = gpiod_get_value_cansleep(data->id_gpiod);

        if (id) {
                /*
                 * ID = 1 means USB HOST cable detached.
                 * As we don't have event for USB peripheral cable attached,
                 * we simulate USB peripheral attach here.
                 */
                extcon_set_state_sync(data->edev, EXTCON_USB_HOST, false);
                extcon_set_state_sync(data->edev, EXTCON_USB, true);
        } else {
                /*
                 * ID = 0 means USB HOST cable attached.
                 * As we don't have event for USB peripheral cable detached,
                 * we simulate USB peripheral detach here.
                 */
                extcon_set_state_sync(data->edev, EXTCON_USB, false);
                extcon_set_state_sync(data->edev, EXTCON_USB_HOST, true);
        }

        return IRQ_HANDLED;
}

static int max3355_probe(struct platform_device *pdev)
{
        struct max3355_data *data;
        struct gpio_desc *gpiod;
        int irq, err;

        data = devm_kzalloc(&pdev->dev, sizeof(struct max3355_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
        if (IS_ERR(gpiod)) {
                dev_err(&pdev->dev, "failed to get ID_OUT GPIO\n");
                return PTR_ERR(gpiod);
        }
        data->id_gpiod = gpiod;

        gpiod = devm_gpiod_get(&pdev->dev, "maxim,shdn", GPIOD_OUT_HIGH);
        if (IS_ERR(gpiod)) {
                dev_err(&pdev->dev, "failed to get SHDN# GPIO\n");
                return PTR_ERR(gpiod);
        }
        data->shdn_gpiod = gpiod;

        data->edev = devm_extcon_dev_allocate(&pdev->dev, max3355_cable);
        if (IS_ERR(data->edev)) {
                dev_err(&pdev->dev, "failed to allocate extcon device\n");
                return PTR_ERR(data->edev);
        }

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

        irq = gpiod_to_irq(data->id_gpiod);
        if (irq < 0) {
                dev_err(&pdev->dev, "failed to translate ID_OUT GPIO to IRQ\n");
                return irq;
        }

        err = devm_request_threaded_irq(&pdev->dev, irq, NULL, max3355_id_irq,
                                        IRQF_ONESHOT | IRQF_NO_SUSPEND |
                                        IRQF_TRIGGER_RISING |
                                        IRQF_TRIGGER_FALLING,
                                        pdev->name, data);
        if (err < 0) {
                dev_err(&pdev->dev, "failed to request ID_OUT IRQ\n");
                return err;
        }

        platform_set_drvdata(pdev, data);

        /* Perform initial detection */
        max3355_id_irq(irq, data);

        return 0;
}

static void max3355_remove(struct platform_device *pdev)
{
        struct max3355_data *data = platform_get_drvdata(pdev);

        gpiod_set_value_cansleep(data->shdn_gpiod, 0);
}

static const struct of_device_id max3355_match_table[] = {
        { .compatible = "maxim,max3355", },
        { }
};
MODULE_DEVICE_TABLE(of, max3355_match_table);

static struct platform_driver max3355_driver = {
        .probe          = max3355_probe,
        .remove         = max3355_remove,
        .driver         = {
                .name   = "extcon-max3355",
                .of_match_table = max3355_match_table,
        },
};

module_platform_driver(max3355_driver);

MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>");
MODULE_DESCRIPTION("Maxim MAX3355 extcon driver");
MODULE_LICENSE("GPL v2");