1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * NXP LPC18xx/43xx OTP memory NVMEM driver |
4 | * |
5 | * Copyright (c) 2016 Joachim Eastwood <manabian@gmail.com> |
6 | * |
7 | * Based on the imx ocotp driver, |
8 | * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de> |
9 | * |
10 | * TODO: add support for writing OTP register via API in boot ROM. |
11 | */ |
12 | |
13 | #include <linux/io.h> |
14 | #include <linux/module.h> |
15 | #include <linux/nvmem-provider.h> |
16 | #include <linux/of.h> |
17 | #include <linux/platform_device.h> |
18 | #include <linux/slab.h> |
19 | |
20 | /* |
21 | * LPC18xx OTP memory contains 4 banks with 4 32-bit words. Bank 0 starts |
22 | * at offset 0 from the base. |
23 | * |
24 | * Bank 0 contains the part ID for Flashless devices and is reseverd for |
25 | * devices with Flash. |
26 | * Bank 1/2 is generale purpose or AES key storage for secure devices. |
27 | * Bank 3 contains control data, USB ID and generale purpose words. |
28 | */ |
29 | #define LPC18XX_OTP_NUM_BANKS 4 |
30 | #define LPC18XX_OTP_WORDS_PER_BANK 4 |
31 | #define LPC18XX_OTP_WORD_SIZE sizeof(u32) |
32 | #define LPC18XX_OTP_SIZE (LPC18XX_OTP_NUM_BANKS * \ |
33 | LPC18XX_OTP_WORDS_PER_BANK * \ |
34 | LPC18XX_OTP_WORD_SIZE) |
35 | |
36 | struct lpc18xx_otp { |
37 | void __iomem *base; |
38 | }; |
39 | |
40 | static int lpc18xx_otp_read(void *context, unsigned int offset, |
41 | void *val, size_t bytes) |
42 | { |
43 | struct lpc18xx_otp *otp = context; |
44 | unsigned int count = bytes >> 2; |
45 | u32 index = offset >> 2; |
46 | u32 *buf = val; |
47 | int i; |
48 | |
49 | if (count > (LPC18XX_OTP_SIZE - index)) |
50 | count = LPC18XX_OTP_SIZE - index; |
51 | |
52 | for (i = index; i < (index + count); i++) |
53 | *buf++ = readl(addr: otp->base + i * LPC18XX_OTP_WORD_SIZE); |
54 | |
55 | return 0; |
56 | } |
57 | |
58 | static struct nvmem_config lpc18xx_otp_nvmem_config = { |
59 | .name = "lpc18xx-otp" , |
60 | .read_only = true, |
61 | .word_size = LPC18XX_OTP_WORD_SIZE, |
62 | .stride = LPC18XX_OTP_WORD_SIZE, |
63 | .reg_read = lpc18xx_otp_read, |
64 | }; |
65 | |
66 | static int lpc18xx_otp_probe(struct platform_device *pdev) |
67 | { |
68 | struct nvmem_device *nvmem; |
69 | struct lpc18xx_otp *otp; |
70 | |
71 | otp = devm_kzalloc(dev: &pdev->dev, size: sizeof(*otp), GFP_KERNEL); |
72 | if (!otp) |
73 | return -ENOMEM; |
74 | |
75 | otp->base = devm_platform_ioremap_resource(pdev, index: 0); |
76 | if (IS_ERR(ptr: otp->base)) |
77 | return PTR_ERR(ptr: otp->base); |
78 | |
79 | lpc18xx_otp_nvmem_config.size = LPC18XX_OTP_SIZE; |
80 | lpc18xx_otp_nvmem_config.dev = &pdev->dev; |
81 | lpc18xx_otp_nvmem_config.priv = otp; |
82 | |
83 | nvmem = devm_nvmem_register(dev: &pdev->dev, cfg: &lpc18xx_otp_nvmem_config); |
84 | |
85 | return PTR_ERR_OR_ZERO(ptr: nvmem); |
86 | } |
87 | |
88 | static const struct of_device_id lpc18xx_otp_dt_ids[] = { |
89 | { .compatible = "nxp,lpc1850-otp" }, |
90 | { }, |
91 | }; |
92 | MODULE_DEVICE_TABLE(of, lpc18xx_otp_dt_ids); |
93 | |
94 | static struct platform_driver lpc18xx_otp_driver = { |
95 | .probe = lpc18xx_otp_probe, |
96 | .driver = { |
97 | .name = "lpc18xx_otp" , |
98 | .of_match_table = lpc18xx_otp_dt_ids, |
99 | }, |
100 | }; |
101 | module_platform_driver(lpc18xx_otp_driver); |
102 | |
103 | MODULE_AUTHOR("Joachim Eastwoood <manabian@gmail.com>" ); |
104 | MODULE_DESCRIPTION("NXP LPC18xx OTP NVMEM driver" ); |
105 | MODULE_LICENSE("GPL v2" ); |
106 | |