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b6b7ef93 SP |
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 | .read_only = true, | |
40 | .reg_read = apple_efuses_read, | |
41 | .stride = sizeof(u32), | |
42 | .word_size = sizeof(u32), | |
43 | .name = "apple_efuses_nvmem", | |
44 | .id = NVMEM_DEVID_AUTO, | |
45 | .root_only = true, | |
46 | }; | |
47 | ||
48 | priv = devm_kzalloc(config.dev, sizeof(*priv), GFP_KERNEL); | |
49 | if (!priv) | |
50 | return -ENOMEM; | |
51 | ||
52 | priv->fuses = devm_platform_get_and_ioremap_resource(pdev, 0, &res); | |
53 | if (IS_ERR(priv->fuses)) | |
54 | return PTR_ERR(priv->fuses); | |
55 | ||
56 | config.priv = priv; | |
57 | config.size = resource_size(res); | |
58 | ||
59 | return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config)); | |
60 | } | |
61 | ||
62 | static const struct of_device_id apple_efuses_of_match[] = { | |
63 | { .compatible = "apple,efuses", }, | |
64 | {} | |
65 | }; | |
66 | ||
67 | MODULE_DEVICE_TABLE(of, apple_efuses_of_match); | |
68 | ||
69 | static struct platform_driver apple_efuses_driver = { | |
70 | .driver = { | |
71 | .name = "apple_efuses", | |
72 | .of_match_table = apple_efuses_of_match, | |
73 | }, | |
74 | .probe = apple_efuses_probe, | |
75 | }; | |
76 | ||
77 | module_platform_driver(apple_efuses_driver); | |
78 | ||
79 | MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); | |
80 | MODULE_LICENSE("GPL"); |