// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2025 Alexey Charkov <alchark@gmail.com>
 * Based on aspeed-socinfo.c
 */

#include <linux/dev_printk.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/sys_soc.h>

static const struct {
        const char *name;
        const u32 id;
} chip_id_table[] = {
        /* VIA */
        { "VT8420", 0x3300 },
        { "VT8430", 0x3357 },
        { "VT8500", 0x3400 },

        /* WonderMedia */
        { "WM8425", 0x3429 },
        { "WM8435", 0x3437 },
        { "WM8440", 0x3451 },
        { "WM8505", 0x3426 },
        { "WM8650", 0x3465 },
        { "WM8750", 0x3445 },
        { "WM8850", 0x3481 },
        { "WM8880", 0x3498 },
};

static const char *sccid_to_name(u32 sccid)
{
        u32 id = sccid >> 16;
        unsigned int i;

        for (i = 0 ; i < ARRAY_SIZE(chip_id_table) ; ++i) {
                if (chip_id_table[i].id == id)
                        return chip_id_table[i].name;
        }

        return "Unknown";
}

static int wmt_socinfo_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct soc_device_attribute *attrs;
        struct soc_device *soc_dev;
        char letter, digit;
        void __iomem *reg;
        u32 sccid;

        reg = devm_of_iomap(&pdev->dev, np, 0, NULL);
        if (IS_ERR(reg))
                return PTR_ERR(reg);

        sccid = readl(reg);

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

        /*
         * Machine: VIA APC Rock
         * Family: WM8850
         * Revision: A2
         * SoC ID: raw silicon revision id (34810103 in hexadecimal)
         */

        attrs->family = sccid_to_name(sccid);

        letter = (sccid >> 8) & 0xf;
        letter = (letter - 1) + 'A';
        digit = sccid & 0xff;
        digit = (digit - 1) + '0';
        attrs->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL,
                                         "%c%c", letter, digit);

        attrs->soc_id = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%08x", sccid);

        if (!attrs->revision || !attrs->soc_id)
                return -ENOMEM;

        soc_dev = soc_device_register(attrs);
        if (IS_ERR(soc_dev))
                return PTR_ERR(soc_dev);

        dev_info(&pdev->dev,
                 "VIA/WonderMedia %s rev %s (%s)\n",
                 attrs->family,
                 attrs->revision,
                 attrs->soc_id);

        platform_set_drvdata(pdev, soc_dev);
        return 0;
}

static void wmt_socinfo_remove(struct platform_device *pdev)
{
        struct soc_device *soc_dev = platform_get_drvdata(pdev);

        soc_device_unregister(soc_dev);
}

static const struct of_device_id wmt_socinfo_ids[] = {
        { .compatible = "via,vt8500-scc-id" },
        { /* Sentinel */ },
};

static struct platform_driver wmt_socinfo = {
        .probe = wmt_socinfo_probe,
        .remove = wmt_socinfo_remove,
        .driver = {
                .name = "wmt-socinfo",
                .of_match_table = wmt_socinfo_ids,
        },
};
module_platform_driver(wmt_socinfo);

MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
MODULE_DESCRIPTION("VIA/WonderMedia socinfo driver");
MODULE_LICENSE("GPL");