// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017-18 Linaro Limited

#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/reboot-mode.h>
#include <linux/regmap.h>

#define PON_SOFT_RB_SPARE               0x8f

#define GEN1_REASON_SHIFT               2
#define GEN2_REASON_SHIFT               1

#define NO_REASON_SHIFT                 0

struct qcom_pon {
        struct device *dev;
        struct regmap *regmap;
        u32 baseaddr;
        struct reboot_mode_driver reboot_mode;
        long reason_shift;
};

static int qcom_pon_reboot_mode_write(struct reboot_mode_driver *reboot,
                                    unsigned int magic)
{
        struct qcom_pon *pon = container_of
                        (reboot, struct qcom_pon, reboot_mode);
        int ret;

        ret = regmap_update_bits(pon->regmap,
                                 pon->baseaddr + PON_SOFT_RB_SPARE,
                                 GENMASK(7, pon->reason_shift),
                                 magic << pon->reason_shift);
        if (ret < 0)
                dev_err(pon->dev, "update reboot mode bits failed\n");

        return ret;
}

static int qcom_pon_probe(struct platform_device *pdev)
{
        struct qcom_pon *pon;
        long reason_shift;
        int error;

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

        pon->dev = &pdev->dev;

        pon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
        if (!pon->regmap) {
                dev_err(&pdev->dev, "failed to locate regmap\n");
                return -ENODEV;
        }

        error = of_property_read_u32(pdev->dev.of_node, "reg",
                                     &pon->baseaddr);
        if (error)
                return error;

        reason_shift = (long)of_device_get_match_data(&pdev->dev);

        if (reason_shift != NO_REASON_SHIFT) {
                pon->reboot_mode.dev = &pdev->dev;
                pon->reason_shift = reason_shift;
                pon->reboot_mode.write = qcom_pon_reboot_mode_write;
                error = devm_reboot_mode_register(&pdev->dev, &pon->reboot_mode);
                if (error) {
                        dev_err(&pdev->dev, "can't register reboot mode\n");
                        return error;
                }
        }

        platform_set_drvdata(pdev, pon);

        return devm_of_platform_populate(&pdev->dev);
}

static const struct of_device_id qcom_pon_id_table[] = {
        { .compatible = "qcom,pm8916-pon", .data = (void *)GEN1_REASON_SHIFT },
        { .compatible = "qcom,pm8941-pon", .data = (void *)NO_REASON_SHIFT },
        { .compatible = "qcom,pms405-pon", .data = (void *)GEN1_REASON_SHIFT },
        { .compatible = "qcom,pm8998-pon", .data = (void *)GEN2_REASON_SHIFT },
        { .compatible = "qcom,pmk8350-pon", .data = (void *)GEN2_REASON_SHIFT },
        { }
};
MODULE_DEVICE_TABLE(of, qcom_pon_id_table);

static struct platform_driver qcom_pon_driver = {
        .probe = qcom_pon_probe,
        .driver = {
                .name = "qcom-pon",
                .of_match_table = qcom_pon_id_table,
        },
};
module_platform_driver(qcom_pon_driver);

MODULE_DESCRIPTION("Qualcomm Power On driver");
MODULE_LICENSE("GPL v2");