// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Driver for Samsung Q10 and related laptops: controls the backlight
 *
 *  Copyright (c) 2011 Frederick van der Wyck <fvanderwyck@gmail.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/backlight.h>
#include <linux/dmi.h>
#include <linux/acpi.h>

#define SAMSUNGQ10_BL_MAX_INTENSITY 7

static acpi_handle ec_handle;

static bool force;
module_param(force, bool, 0);
MODULE_PARM_DESC(force,
                "Disable the DMI check and force the driver to be loaded");

static int samsungq10_bl_set_intensity(struct backlight_device *bd)
{

        acpi_status status;
        int i;

        for (i = 0; i < SAMSUNGQ10_BL_MAX_INTENSITY; i++) {
                status = acpi_evaluate_object(ec_handle, "_Q63", NULL, NULL);
                if (ACPI_FAILURE(status))
                        return -EIO;
        }
        for (i = 0; i < bd->props.brightness; i++) {
                status = acpi_evaluate_object(ec_handle, "_Q64", NULL, NULL);
                if (ACPI_FAILURE(status))
                        return -EIO;
        }

        return 0;
}

static const struct backlight_ops samsungq10_bl_ops = {
        .update_status  = samsungq10_bl_set_intensity,
};

static int samsungq10_probe(struct platform_device *pdev)
{

        struct backlight_properties props;
        struct backlight_device *bd;

        memset(&props, 0, sizeof(struct backlight_properties));
        props.type = BACKLIGHT_PLATFORM;
        props.max_brightness = SAMSUNGQ10_BL_MAX_INTENSITY;
        bd = backlight_device_register("samsung", &pdev->dev, NULL,
                                       &samsungq10_bl_ops, &props);
        if (IS_ERR(bd))
                return PTR_ERR(bd);

        platform_set_drvdata(pdev, bd);

        return 0;
}

static void samsungq10_remove(struct platform_device *pdev)
{

        struct backlight_device *bd = platform_get_drvdata(pdev);

        backlight_device_unregister(bd);
}

static struct platform_driver samsungq10_driver = {
        .driver         = {
                .name   = KBUILD_MODNAME,
        },
        .probe          = samsungq10_probe,
        .remove         = samsungq10_remove,
};

static struct platform_device *samsungq10_device;

static int __init dmi_check_callback(const struct dmi_system_id *id)
{
        printk(KERN_INFO KBUILD_MODNAME ": found model '%s'\n", id->ident);
        return 1;
}

static const struct dmi_system_id samsungq10_dmi_table[] __initconst = {
        {
                .ident = "Samsung Q10",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Samsung"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "SQ10"),
                },
                .callback = dmi_check_callback,
        },
        {
                .ident = "Samsung Q20",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "SENS Q20"),
                },
                .callback = dmi_check_callback,
        },
        {
                .ident = "Samsung Q25",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "NQ25"),
                },
                .callback = dmi_check_callback,
        },
        {
                .ident = "Dell Latitude X200",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "X200"),
                },
                .callback = dmi_check_callback,
        },
        { },
};
MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);

static int __init samsungq10_init(void)
{
        if (!force && !dmi_check_system(samsungq10_dmi_table))
                return -ENODEV;

        ec_handle = ec_get_handle();

        if (!ec_handle)
                return -ENODEV;

        samsungq10_device = platform_create_bundle(&samsungq10_driver,
                                                   samsungq10_probe,
                                                   NULL, 0, NULL, 0);

        return PTR_ERR_OR_ZERO(samsungq10_device);
}

static void __exit samsungq10_exit(void)
{
        platform_device_unregister(samsungq10_device);
        platform_driver_unregister(&samsungq10_driver);
}

module_init(samsungq10_init);
module_exit(samsungq10_exit);

MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
MODULE_DESCRIPTION("Samsung Q10 Driver");
MODULE_LICENSE("GPL");