drivers/soc/vt8500/wmt-socinfo.c

// 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");