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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * NXP LPC18xx/43xx OTP memory NVMEM driver4 *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 starts22 * at offset 0 from the base.23 *24 * Bank 0 contains the part ID for Flashless devices and is reseverd for25 * 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 430#define LPC18XX_OTP_WORDS_PER_BANK 431#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 36struct lpc18xx_otp {37 void __iomem *base;38};39 40static 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(otp->base + i * LPC18XX_OTP_WORD_SIZE);54 55 return 0;56}57 58static 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 66static int lpc18xx_otp_probe(struct platform_device *pdev)67{68 struct nvmem_device *nvmem;69 struct lpc18xx_otp *otp;70 71 otp = devm_kzalloc(&pdev->dev, sizeof(*otp), GFP_KERNEL);72 if (!otp)73 return -ENOMEM;74 75 otp->base = devm_platform_ioremap_resource(pdev, 0);76 if (IS_ERR(otp->base))77 return PTR_ERR(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(&pdev->dev, &lpc18xx_otp_nvmem_config);84 85 return PTR_ERR_OR_ZERO(nvmem);86}87 88static const struct of_device_id lpc18xx_otp_dt_ids[] = {89 { .compatible = "nxp,lpc1850-otp" },90 { },91};92MODULE_DEVICE_TABLE(of, lpc18xx_otp_dt_ids);93 94static 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};101module_platform_driver(lpc18xx_otp_driver);102 103MODULE_AUTHOR("Joachim Eastwoood <manabian@gmail.com>");104MODULE_DESCRIPTION("NXP LPC18xx OTP NVMEM driver");105MODULE_LICENSE("GPL v2");106