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88806daf JE |
1 | /* |
2 | * NXP LPC18xx/43xx OTP memory NVMEM driver | |
3 | * | |
4 | * Copyright (c) 2016 Joachim Eastwood <manabian@gmail.com> | |
5 | * | |
6 | * Based on the imx ocotp driver, | |
7 | * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 | |
11 | * as published by the Free Software Foundation. | |
12 | * | |
13 | * TODO: add support for writing OTP register via API in boot ROM. | |
14 | */ | |
15 | ||
16 | #include <linux/io.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/nvmem-provider.h> | |
19 | #include <linux/of.h> | |
20 | #include <linux/of_device.h> | |
21 | #include <linux/platform_device.h> | |
22 | #include <linux/slab.h> | |
23 | ||
24 | /* | |
25 | * LPC18xx OTP memory contains 4 banks with 4 32-bit words. Bank 0 starts | |
26 | * at offset 0 from the base. | |
27 | * | |
28 | * Bank 0 contains the part ID for Flashless devices and is reseverd for | |
29 | * devices with Flash. | |
30 | * Bank 1/2 is generale purpose or AES key storage for secure devices. | |
31 | * Bank 3 contains control data, USB ID and generale purpose words. | |
32 | */ | |
33 | #define LPC18XX_OTP_NUM_BANKS 4 | |
34 | #define LPC18XX_OTP_WORDS_PER_BANK 4 | |
35 | #define LPC18XX_OTP_WORD_SIZE sizeof(u32) | |
36 | #define LPC18XX_OTP_SIZE (LPC18XX_OTP_NUM_BANKS * \ | |
37 | LPC18XX_OTP_WORDS_PER_BANK * \ | |
38 | LPC18XX_OTP_WORD_SIZE) | |
39 | ||
40 | struct lpc18xx_otp { | |
41 | void __iomem *base; | |
42 | }; | |
43 | ||
44 | static int lpc18xx_otp_read(void *context, unsigned int offset, | |
45 | void *val, size_t bytes) | |
46 | { | |
47 | struct lpc18xx_otp *otp = context; | |
48 | unsigned int count = bytes >> 2; | |
49 | u32 index = offset >> 2; | |
50 | u32 *buf = val; | |
51 | int i; | |
52 | ||
53 | if (count > (LPC18XX_OTP_SIZE - index)) | |
54 | count = LPC18XX_OTP_SIZE - index; | |
55 | ||
56 | for (i = index; i < (index + count); i++) | |
57 | *buf++ = readl(otp->base + i * LPC18XX_OTP_WORD_SIZE); | |
58 | ||
59 | return 0; | |
60 | } | |
61 | ||
62 | static struct nvmem_config lpc18xx_otp_nvmem_config = { | |
63 | .name = "lpc18xx-otp", | |
64 | .read_only = true, | |
65 | .word_size = LPC18XX_OTP_WORD_SIZE, | |
66 | .stride = LPC18XX_OTP_WORD_SIZE, | |
88806daf JE |
67 | .reg_read = lpc18xx_otp_read, |
68 | }; | |
69 | ||
70 | static int lpc18xx_otp_probe(struct platform_device *pdev) | |
71 | { | |
72 | struct nvmem_device *nvmem; | |
73 | struct lpc18xx_otp *otp; | |
74 | struct resource *res; | |
75 | ||
76 | otp = devm_kzalloc(&pdev->dev, sizeof(*otp), GFP_KERNEL); | |
77 | if (!otp) | |
78 | return -ENOMEM; | |
79 | ||
80 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
81 | otp->base = devm_ioremap_resource(&pdev->dev, res); | |
82 | if (IS_ERR(otp->base)) | |
83 | return PTR_ERR(otp->base); | |
84 | ||
85 | lpc18xx_otp_nvmem_config.size = LPC18XX_OTP_SIZE; | |
86 | lpc18xx_otp_nvmem_config.dev = &pdev->dev; | |
87 | lpc18xx_otp_nvmem_config.priv = otp; | |
88 | ||
b005b2f5 | 89 | nvmem = devm_nvmem_register(&pdev->dev, &lpc18xx_otp_nvmem_config); |
88806daf | 90 | |
b005b2f5 | 91 | return PTR_ERR_OR_ZERO(nvmem); |
88806daf JE |
92 | } |
93 | ||
94 | static const struct of_device_id lpc18xx_otp_dt_ids[] = { | |
95 | { .compatible = "nxp,lpc1850-otp" }, | |
96 | { }, | |
97 | }; | |
98 | MODULE_DEVICE_TABLE(of, lpc18xx_otp_dt_ids); | |
99 | ||
100 | static struct platform_driver lpc18xx_otp_driver = { | |
101 | .probe = lpc18xx_otp_probe, | |
88806daf JE |
102 | .driver = { |
103 | .name = "lpc18xx_otp", | |
104 | .of_match_table = lpc18xx_otp_dt_ids, | |
105 | }, | |
106 | }; | |
107 | module_platform_driver(lpc18xx_otp_driver); | |
108 | ||
109 | MODULE_AUTHOR("Joachim Eastwoood <manabian@gmail.com>"); | |
110 | MODULE_DESCRIPTION("NXP LPC18xx OTP NVMEM driver"); | |
111 | MODULE_LICENSE("GPL v2"); |