[PATCH 05/13] nvmem: add mt6323 PMIC EFUSE driver

Roman Vivchar via B4 Relay
2026-05-04T18:24:59Z

From: Roman Vivchar <rva333@protonmail.com>

Add support for the EFUSE controller found in the Mediatek MT6323 PMIC.
The MT6323 EFUSE stores 24 bytes of hardware-related data, such as
thermal sensor calibration values.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
drivers/nvmem/Kconfig | 11 ++++++
drivers/nvmem/Makefile | 2 ++
drivers/nvmem/mt6323-efuse.c | 86 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 99 insertions(+)

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 74ddbd0f79b0..db248a3c4e87 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -227,6 +227,17 @@ config NVMEM_MTK_EFUSE
This driver can also be built as a module. If so, the module
will be called efuse-mtk.

+config NVMEM_MT6323_EFUSE
+ tristate "Mediatek MT6323 PMIC EFUSE support"
+ depends on ARCH_MEDIATEK || COMPILE_TEST
+ depends on MFD_MT6397
+ help
+ This is a driver to access hardware related data like sensor
+ calibration, etc.
+
+ This driver can also be built as a module. If so, the module
+ will be called efuse-mt6323.
+
config NVMEM_MXS_OCOTP
tristate "Freescale MXS On-Chip OTP Memory Support"
depends on ARCH_MXS || COMPILE_TEST
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 7252b8ec88d4..0e2b73f42b25 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -48,6 +48,8 @@ obj-$(CONFIG_NVMEM_MICROCHIP_OTPC) += nvmem-microchip-otpc.o
nvmem-microchip-otpc-y := microchip-otpc.o
obj-$(CONFIG_NVMEM_MTK_EFUSE) += nvmem_mtk-efuse.o
nvmem_mtk-efuse-y := mtk-efuse.o
+obj-$(CONFIG_NVMEM_MT6323_EFUSE) += nvmem_mt6323-efuse.o
+nvmem_mt6323-efuse-y := mt6323-efuse.o
obj-$(CONFIG_NVMEM_MXS_OCOTP) += nvmem-mxs-ocotp.o
nvmem-mxs-ocotp-y := mxs-ocotp.o
obj-$(CONFIG_NVMEM_NINTENDO_OTP) += nvmem-nintendo-otp.o
diff --git a/drivers/nvmem/mt6323-efuse.c b/drivers/nvmem/mt6323-efuse.c
new file mode 100644
index 000000000000..0c1b405fbc89
--- /dev/null
+++ b/drivers/nvmem/mt6323-efuse.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2026 Roman Vivchar <rva333@protonmail.com>
+ */
+
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/mfd/mt6323/registers.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define MT6323_EFUSE_DOUT_BASE MT6323_EFUSE_DOUT_0_15
+#define MT6323_EFUSE_SIZE 24
+
+struct mt6323_efuse {
+ struct regmap *regmap;
+};
+
+static int mt6323_efuse_read(void *context, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct mt6323_efuse *efuse = context;
+ u32 tmp;
+ u16 *buf = val;
+ int i, ret;
+
+ for (i = 0; i < bytes; i += 2) {
+ ret = regmap_read(efuse->regmap,
+ MT6323_EFUSE_DOUT_BASE + offset + i, &tmp);
+ if (ret)
+ return ret;
+ buf[i / 2] = tmp;
+ }
+ return 0;
+}
+
+static int mt6323_efuse_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mt6323_efuse *priv;
+ struct nvmem_config config = {
+ .name = "mt6323-efuse",
+ .stride = 2,
+ .word_size = 2,
+ .size = MT6323_EFUSE_SIZE,
+ .reg_read = mt6323_efuse_read,
+ };
+ struct nvmem_device *nvmem;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ /* efuse -> mfd -> pwrap */
+ priv->regmap = dev_get_regmap(dev->parent->parent, NULL);
+ if (!priv->regmap)
+ return -ENODEV;
+
+ config.dev = dev;
+ config.priv = priv;
+
+ nvmem = devm_nvmem_register(dev, &config);
+ return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static const struct of_device_id mt6323_efuse_of_match[] = {
+ { .compatible = "mediatek,mt6323-efuse" },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mt6323_efuse_of_match);
+
+static struct platform_driver mt6323_efuse_driver = {
+ .probe = mt6323_efuse_probe,
+ .driver = {
+ .name = "mt6323-efuse",
+ .of_match_table = mt6323_efuse_of_match,
+ },
+};
+module_platform_driver(mt6323_efuse_driver);
+
+MODULE_DESCRIPTION("Mediatek MT6323 PMIC EFUSE driver");
+MODULE_LICENSE("GPL");

--
2.53.0