1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Apple SoC eFuse driver
4 *
5 * Copyright (C) The Asahi Linux Contributors
6 */
7
8#include <linux/io.h>
9#include <linux/mod_devicetable.h>
10#include <linux/module.h>
11#include <linux/nvmem-provider.h>
12#include <linux/platform_device.h>
13
14struct apple_efuses_priv {
15	void __iomem *fuses;
16};
17
18static int apple_efuses_read(void *context, unsigned int offset, void *val,
19			     size_t bytes)
20{
21	struct apple_efuses_priv *priv = context;
22	u32 *dst = val;
23
24	while (bytes >= sizeof(u32)) {
25		*dst++ = readl_relaxed(priv->fuses + offset);
26		bytes -= sizeof(u32);
27		offset += sizeof(u32);
28	}
29
30	return 0;
31}
32
33static int apple_efuses_probe(struct platform_device *pdev)
34{
35	struct apple_efuses_priv *priv;
36	struct resource *res;
37	struct nvmem_config config = {
38		.dev = &pdev->dev,
39		.add_legacy_fixed_of_cells = true,
40		.read_only = true,
41		.reg_read = apple_efuses_read,
42		.stride = sizeof(u32),
43		.word_size = sizeof(u32),
44		.name = "apple_efuses_nvmem",
45		.id = NVMEM_DEVID_AUTO,
46		.root_only = true,
47	};
48
49	priv = devm_kzalloc(config.dev, sizeof(*priv), GFP_KERNEL);
50	if (!priv)
51		return -ENOMEM;
52
53	priv->fuses = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
54	if (IS_ERR(priv->fuses))
55		return PTR_ERR(priv->fuses);
56
57	config.priv = priv;
58	config.size = resource_size(res);
59
60	return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config));
61}
62
63static const struct of_device_id apple_efuses_of_match[] = {
64	{ .compatible = "apple,efuses", },
65	{}
66};
67
68MODULE_DEVICE_TABLE(of, apple_efuses_of_match);
69
70static struct platform_driver apple_efuses_driver = {
71	.driver = {
72		.name = "apple_efuses",
73		.of_match_table = apple_efuses_of_match,
74	},
75	.probe = apple_efuses_probe,
76};
77
78module_platform_driver(apple_efuses_driver);
79
80MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
81MODULE_LICENSE("GPL");
82