summaryrefslogtreecommitdiffstats
path: root/drivers/nvmem/lpc18xx_otp.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/nvmem/lpc18xx_otp.c')
-rw-r--r--drivers/nvmem/lpc18xx_otp.c108
1 files changed, 108 insertions, 0 deletions
diff --git a/drivers/nvmem/lpc18xx_otp.c b/drivers/nvmem/lpc18xx_otp.c
new file mode 100644
index 000000000..16c92ea85
--- /dev/null
+++ b/drivers/nvmem/lpc18xx_otp.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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>
+ *
+ * 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");