/*
* NXP LPC18xx/43xx OTP memory NVMEM driver
*
* Copyright (c) 2016 Joachim Eastwood <manabian@gmail.com>
*
* Based on the imx ocotp driver,
* Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* TODO: add support for writing OTP register via API in boot ROM.
*/
#include <linux/io.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
/*
* LPC18xx OTP memory contains 4 banks with 4 32-bit words. Bank 0 starts
* at offset 0 from the base.
*
* Bank 0 contains the part ID for Flashless devices and is reseverd for
* devices with Flash.
* Bank 1/2 is generale purpose or AES key storage for secure devices.
* Bank 3 contains control data, USB ID and generale purpose words.
*/
#define LPC18XX_OTP_NUM_BANKS 4
#define LPC18XX_OTP_WORDS_PER_BANK 4
#define LPC18XX_OTP_WORD_SIZE sizeof(u32)
#define LPC18XX_OTP_SIZE (LPC18XX_OTP_NUM_BANKS * \
LPC18XX_OTP_WORDS_PER_BANK * \
LPC18XX_OTP_WORD_SIZE)
struct lpc18xx_otp {
void __iomem *base;
};
static int lpc18xx_otp_read(void *context, unsigned int offset,
void *val, size_t bytes)
{
struct lpc18xx_otp *otp = context;
unsigned int count = bytes >> 2;
u32 index = offset >> 2;
u32 *buf = val;
int i;
if (count > (LPC18XX_OTP_SIZE - index))
count = LPC18XX_OTP_SIZE - index;
for (i = index; i < (index + count); i++)
*buf++ = readl(otp->base + i * LPC18XX_OTP_WORD_SIZE);
return 0;
}
static struct nvmem_config lpc18xx_otp_nvmem_config = {
.name = "lpc18xx-otp",
.read_only = true,
.word_size = LPC18XX_OTP_WORD_SIZE,
.stride = LPC18XX_OTP_WORD_SIZE,
.reg_read = lpc18xx_otp_read,
};
static int lpc18xx_otp_probe(struct platform_device *pdev)
{
struct nvmem_device *nvmem;
struct lpc18xx_otp *otp;
struct resource *res;
otp = devm_kzalloc(&pdev->dev, sizeof(*otp), GFP_KERNEL);
if (!otp)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
otp->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(otp->base))
return PTR_ERR(otp->base);
lpc18xx_otp_nvmem_config.size = LPC18XX_OTP_SIZE;
lpc18xx_otp_nvmem_config.dev = &pdev->dev;
lpc18xx_otp_nvmem_config.priv = otp;
nvmem = devm_nvmem_register(&pdev->dev, &lpc18xx_otp_nvmem_config);
return PTR_ERR_OR_ZERO(nvmem);
}
static const struct of_device_id lpc18xx_otp_dt_ids[] = {
{ .compatible = "nxp,lpc1850-otp" },
{ },
};
MODULE_DEVICE_TABLE(of, lpc18xx_otp_dt_ids);
static struct platform_driver lpc18xx_otp_driver = {
.probe = lpc18xx_otp_probe,
.driver = {
.name = "lpc18xx_otp",
.of_match_table = lpc18xx_otp_dt_ids,
},
};
module_platform_driver(lpc18xx_otp_driver);
MODULE_AUTHOR("Joachim Eastwoood <manabian@gmail.com>");
MODULE_DESCRIPTION("NXP LPC18xx OTP NVMEM driver");
MODULE_LICENSE("GPL v2");
