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 | |
14 | struct apple_efuses_priv { |
15 | void __iomem *fuses; |
16 | }; |
17 | |
18 | static 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 | |
33 | static 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(dev: config.dev, size: sizeof(*priv), GFP_KERNEL); |
50 | if (!priv) |
51 | return -ENOMEM; |
52 | |
53 | priv->fuses = devm_platform_get_and_ioremap_resource(pdev, index: 0, res: &res); |
54 | if (IS_ERR(ptr: priv->fuses)) |
55 | return PTR_ERR(ptr: priv->fuses); |
56 | |
57 | config.priv = priv; |
58 | config.size = resource_size(res); |
59 | |
60 | return PTR_ERR_OR_ZERO(ptr: devm_nvmem_register(dev: config.dev, cfg: &config)); |
61 | } |
62 | |
63 | static const struct of_device_id apple_efuses_of_match[] = { |
64 | { .compatible = "apple,efuses" , }, |
65 | {} |
66 | }; |
67 | |
68 | MODULE_DEVICE_TABLE(of, apple_efuses_of_match); |
69 | |
70 | static 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 | |
78 | module_platform_driver(apple_efuses_driver); |
79 | |
80 | MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>" ); |
81 | MODULE_LICENSE("GPL" ); |
82 | |