[PATCH v5 0/3] nvmem: add support for the MediaTek mt6323 PMIC

[PATCH v5 0/3] nvmem: add support for the MediaTek mt6323 PMIC

[Roman Vivchar via B4 Relay]

This series adds support for the EFUSE found on the MediaTek mt6323 PMIC.

Tested on the MediaTek mt6572 and mt8163 SoCs (Ben), both paired with a
mt6323.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>

---
Changes in v5:
- Reorder Makefile entries
- Use mt6323_regulators driver pattern for regmap instead of dev->parent->parent
- Link to v4: https://patch.msgid.link/20260911-mt6323-nvmem-v4-0-626dd17531dc@protonmail.com

Changes in v4:
- Rebase onto nvmem/for-next (8f596c13b6b7 ("dt-bindings: nvmem: qfprom: Add compatible for Qualcomm Maili"))
- Drop device-id/of.h header (Andy)
- Mediatek -> MediaTek in Kconfig
- Link to v3: https://patch.msgid.link/20260713-mt6323-nvmem-v3-0-205c39267a24@protonmail.com

Changes in v3:
- Rebase onto next-20260708
- EFUSE driver: Replace 'mod_devicetable.h' with explicit 'device-id/of.h'
- Drop MFD patch since it's applied
- Link to v2: https://patch.msgid.link/20260617-mt6323-nvmem-v2-0-4f30e36aa0f4@protonmail.com

Changes in v2:
- EFUSE driver: Sort variables in the mt6323_efuse_read (Andy)
- Link to v1: https://patch.msgid.link/20260611-mt6323-nvmem-v1-0-b5e1b9ce51f2@protonmail.com

Changes after split:
- EFUSE driver:
    - Remove 'linux/errno.h' header (Andy)
    - Remove explicit cast to u16 in the 'mt6323_efuse_read' (Andy)
    - Reword comment in the 'mt6323_efuse_read'
    - Capitalize MediaTek in the module description
- Link to a previous series: https://patch.msgid.link/20260512-mt6323-v2-0-3efcba579e88@protonmail.com

---
Roman Vivchar (3):
      dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE
      nvmem: add mt6323 PMIC EFUSE driver
      ARM: dts: mediatek: mt6323: add EFUSE support

 .../devicetree/bindings/mfd/mediatek,mt6397.yaml   | 21 ++++++
 MAINTAINERS                                        |  5 ++
 arch/arm/boot/dts/mediatek/mt6323.dtsi             |  4 ++
 drivers/nvmem/Kconfig                              | 11 +++
 drivers/nvmem/Makefile                             |  2 +
 drivers/nvmem/mt6323-efuse.c                       | 83 ++++++++++++++++++++++
 6 files changed, 126 insertions(+)
---
base-commit: 8f596c13b6b7fa9fa35091273c37f9b6e3fc2d0f
change-id: 20260611-mt6323-nvmem-0c54a0f2fa9f

Best regards,
--  
Roman Vivchar <rva333@protonmail.com>

[PATCH v5 0/3] nvmem: add support for the MediaTek mt6323 PMIC

[Roman Vivchar]

This series adds support for the EFUSE found on the MediaTek mt6323 PMIC.

Tested on the MediaTek mt6572 and mt8163 SoCs (Ben), both paired with a
mt6323.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>

---
Changes in v5:
- Reorder Makefile entries
- Use mt6323_regulators driver pattern for regmap instead of dev->parent->parent
- Link to v4: https://patch.msgid.link/20260911-mt6323-nvmem-v4-0-626dd17531dc@protonmail.com

Changes in v4:
- Rebase onto nvmem/for-next (8f596c13b6b7 ("dt-bindings: nvmem: qfprom: Add compatible for Qualcomm Maili"))
- Drop device-id/of.h header (Andy)
- Mediatek -> MediaTek in Kconfig
- Link to v3: https://patch.msgid.link/20260713-mt6323-nvmem-v3-0-205c39267a24@protonmail.com

Changes in v3:
- Rebase onto next-20260708
- EFUSE driver: Replace 'mod_devicetable.h' with explicit 'device-id/of.h'
- Drop MFD patch since it's applied
- Link to v2: https://patch.msgid.link/20260617-mt6323-nvmem-v2-0-4f30e36aa0f4@protonmail.com

Changes in v2:
- EFUSE driver: Sort variables in the mt6323_efuse_read (Andy)
- Link to v1: https://patch.msgid.link/20260611-mt6323-nvmem-v1-0-b5e1b9ce51f2@protonmail.com

Changes after split:
- EFUSE driver:
    - Remove 'linux/errno.h' header (Andy)
    - Remove explicit cast to u16 in the 'mt6323_efuse_read' (Andy)
    - Reword comment in the 'mt6323_efuse_read'
    - Capitalize MediaTek in the module description
- Link to a previous series: https://patch.msgid.link/20260512-mt6323-v2-0-3efcba579e88@protonmail.com

---
Roman Vivchar (3):
      dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE
      nvmem: add mt6323 PMIC EFUSE driver
      ARM: dts: mediatek: mt6323: add EFUSE support

 .../devicetree/bindings/mfd/mediatek,mt6397.yaml   | 21 ++++++
 MAINTAINERS                                        |  5 ++
 arch/arm/boot/dts/mediatek/mt6323.dtsi             |  4 ++
 drivers/nvmem/Kconfig                              | 11 +++
 drivers/nvmem/Makefile                             |  2 +
 drivers/nvmem/mt6323-efuse.c                       | 83 ++++++++++++++++++++++
 6 files changed, 126 insertions(+)
---
base-commit: 8f596c13b6b7fa9fa35091273c37f9b6e3fc2d0f
change-id: 20260611-mt6323-nvmem-0c54a0f2fa9f

Best regards,
--  
Roman Vivchar <rva333@protonmail.com>

[PATCH v5 1/3] dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@protonmail.com>

The MediaTek mt6323 PMIC includes an EFUSE used for storing calibration
data.

Add the devicetree binding documentation for the MediaTek mt6323 EFUSE.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 .../devicetree/bindings/mfd/mediatek,mt6397.yaml    | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
index 3cbc0dc12c31..d2de227ae7a6 100644
--- a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
+++ b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
@@ -159,6 +159,23 @@ properties:
     required:
       - compatible
 
+  efuse:
+    type: object
+    unevaluatedProperties: false
+    description:
+      The efuse is responsible for storing calibration data, such as thermal
+      sensor calibration.
+
+    properties:
+      compatible:
+        const: mediatek,mt6323-efuse
+
+      nvmem-layout:
+        $ref: /schemas/nvmem/layouts/nvmem-layout.yaml#
+
+    required:
+      - compatible
+
   leds:
     type: object
     additionalProperties: false
@@ -307,6 +324,10 @@ examples:
         interrupt-controller;
         #interrupt-cells = <2>;
 
+        efuse {
+          compatible = "mediatek,mt6323-efuse";
+        };
+
         leds {
             compatible = "mediatek,mt6323-led";
             #address-cells = <1>;

-- 
2.55.0

[PATCH v5 1/3] dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE

[Roman Vivchar]

The MediaTek mt6323 PMIC includes an EFUSE used for storing calibration
data.

Add the devicetree binding documentation for the MediaTek mt6323 EFUSE.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 .../devicetree/bindings/mfd/mediatek,mt6397.yaml    | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
index 3cbc0dc12c31..d2de227ae7a6 100644
--- a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
+++ b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
@@ -159,6 +159,23 @@ properties:
     required:
       - compatible
 
+  efuse:
+    type: object
+    unevaluatedProperties: false
+    description:
+      The efuse is responsible for storing calibration data, such as thermal
+      sensor calibration.
+
+    properties:
+      compatible:
+        const: mediatek,mt6323-efuse
+
+      nvmem-layout:
+        $ref: /schemas/nvmem/layouts/nvmem-layout.yaml#
+
+    required:
+      - compatible
+
   leds:
     type: object
     additionalProperties: false
@@ -307,6 +324,10 @@ examples:
         interrupt-controller;
         #interrupt-cells = <2>;
 
+        efuse {
+          compatible = "mediatek,mt6323-efuse";
+        };
+
         leds {
             compatible = "mediatek,mt6323-led";
             #address-cells = <1>;

-- 
2.55.0

[PATCH v5 2/3] nvmem: add mt6323 PMIC EFUSE driver

[Roman Vivchar via B4 Relay]

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)
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 MAINTAINERS                  |  5 +++
 drivers/nvmem/Kconfig        | 11 ++++++
 drivers/nvmem/Makefile       |  2 ++
 drivers/nvmem/mt6323-efuse.c | 83 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 101 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 3a19da74d00c..6ec0ed61260c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16718,6 +16718,11 @@ S:	Maintained
 F:	drivers/iio/adc/mt6323-auxadc.c
 F:	include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h
 
+MEDIATEK MT6323 PMIC NVMEM DRIVER
+M:	Roman Vivchar <rva333@protonmail.com>
+S:	Maintained
+F:	drivers/nvmem/mt6323-efuse.c
+
 MEDIATEK MT6735 CLOCK & RESET DRIVERS
 M:	Yassine Oudjana <y.oudjana@protonmail.com>
 L:	linux-clk@vger.kernel.org
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index c36c2a4c2a0b..5115c46beb97 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -328,6 +328,17 @@ 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 2bbfb9ff1885..5e70bad9f0f9 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -53,6 +53,8 @@ obj-$(CONFIG_NVMEM_MESON_MX_EFUSE)	+= nvmem_meson_mx_efuse.o
 nvmem_meson_mx_efuse-y			:= meson-mx-efuse.o
 obj-$(CONFIG_NVMEM_MICROCHIP_OTPC)	+= nvmem-microchip-otpc.o
 nvmem-microchip-otpc-y			:= microchip-otpc.o
+obj-$(CONFIG_NVMEM_MT6323_EFUSE)	+= nvmem_mt6323-efuse.o
+nvmem_mt6323-efuse-y			:= mt6323-efuse.o
 obj-$(CONFIG_NVMEM_MTK_EFUSE)		+= nvmem_mtk-efuse.o
 nvmem_mtk-efuse-y			:= mtk-efuse.o
 obj-$(CONFIG_NVMEM_MXS_OCOTP)		+= nvmem-mxs-ocotp.o
diff --git a/drivers/nvmem/mt6323-efuse.c b/drivers/nvmem/mt6323-efuse.c
new file mode 100644
index 000000000000..de5e30215c22
--- /dev/null
+++ b/drivers/nvmem/mt6323-efuse.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2026 Roman Vivchar <rva333@protonmail.com>
+ */
+
+#include <linux/err.h>
+#include <linux/mfd/mt6397/core.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+#include <linux/mfd/mt6323/registers.h>
+
+#define MT6323_EFUSE_DOUT_BASE	MT6323_EFUSE_DOUT_0_15
+#define MT6323_EFUSE_SIZE	24
+
+static int mt6323_efuse_read(void *context, unsigned int offset, void *val,
+			     size_t bytes)
+{
+	struct regmap *map = context;
+	u16 *buf = val;
+	u32 tmp;
+	int ret;
+
+	/*
+	 * A manual loop using regmap_read is required because PWRAP is not
+	 * a continuous MMIO space, but rather a FSM that doesn't implement the
+	 * necessary read callback for the regmap_read_raw and regmap_read_bulk
+	 * functions.
+	 */
+	for (size_t i = 0; i < bytes; i += sizeof(*buf)) {
+		ret = regmap_read(map, MT6323_EFUSE_DOUT_BASE + offset + i, &tmp);
+		if (ret)
+			return ret;
+
+		*buf++ = tmp;
+	}
+
+	return 0;
+}
+
+static int mt6323_efuse_probe(struct platform_device *pdev)
+{
+	struct mt6397_chip *mt6323 = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	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;
+
+	if (!mt6323 || !mt6323->regmap)
+		return dev_err_probe(dev, -ENODEV, "failed to get parent\n");
+
+	config.dev = dev;
+	config.priv = mt6323->regmap;
+
+	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" },
+	{ }
+};
+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");

-- 
2.55.0

[PATCH v5 2/3] nvmem: add mt6323 PMIC EFUSE driver

[Roman Vivchar]

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)
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 MAINTAINERS                  |  5 +++
 drivers/nvmem/Kconfig        | 11 ++++++
 drivers/nvmem/Makefile       |  2 ++
 drivers/nvmem/mt6323-efuse.c | 83 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 101 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 3a19da74d00c..6ec0ed61260c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16718,6 +16718,11 @@ S:	Maintained
 F:	drivers/iio/adc/mt6323-auxadc.c
 F:	include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h
 
+MEDIATEK MT6323 PMIC NVMEM DRIVER
+M:	Roman Vivchar <rva333@protonmail.com>
+S:	Maintained
+F:	drivers/nvmem/mt6323-efuse.c
+
 MEDIATEK MT6735 CLOCK & RESET DRIVERS
 M:	Yassine Oudjana <y.oudjana@protonmail.com>
 L:	linux-clk@vger.kernel.org
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index c36c2a4c2a0b..5115c46beb97 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -328,6 +328,17 @@ 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 2bbfb9ff1885..5e70bad9f0f9 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -53,6 +53,8 @@ obj-$(CONFIG_NVMEM_MESON_MX_EFUSE)	+= nvmem_meson_mx_efuse.o
 nvmem_meson_mx_efuse-y			:= meson-mx-efuse.o
 obj-$(CONFIG_NVMEM_MICROCHIP_OTPC)	+= nvmem-microchip-otpc.o
 nvmem-microchip-otpc-y			:= microchip-otpc.o
+obj-$(CONFIG_NVMEM_MT6323_EFUSE)	+= nvmem_mt6323-efuse.o
+nvmem_mt6323-efuse-y			:= mt6323-efuse.o
 obj-$(CONFIG_NVMEM_MTK_EFUSE)		+= nvmem_mtk-efuse.o
 nvmem_mtk-efuse-y			:= mtk-efuse.o
 obj-$(CONFIG_NVMEM_MXS_OCOTP)		+= nvmem-mxs-ocotp.o
diff --git a/drivers/nvmem/mt6323-efuse.c b/drivers/nvmem/mt6323-efuse.c
new file mode 100644
index 000000000000..de5e30215c22
--- /dev/null
+++ b/drivers/nvmem/mt6323-efuse.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2026 Roman Vivchar <rva333@protonmail.com>
+ */
+
+#include <linux/err.h>
+#include <linux/mfd/mt6397/core.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+#include <linux/mfd/mt6323/registers.h>
+
+#define MT6323_EFUSE_DOUT_BASE	MT6323_EFUSE_DOUT_0_15
+#define MT6323_EFUSE_SIZE	24
+
+static int mt6323_efuse_read(void *context, unsigned int offset, void *val,
+			     size_t bytes)
+{
+	struct regmap *map = context;
+	u16 *buf = val;
+	u32 tmp;
+	int ret;
+
+	/*
+	 * A manual loop using regmap_read is required because PWRAP is not
+	 * a continuous MMIO space, but rather a FSM that doesn't implement the
+	 * necessary read callback for the regmap_read_raw and regmap_read_bulk
+	 * functions.
+	 */
+	for (size_t i = 0; i < bytes; i += sizeof(*buf)) {
+		ret = regmap_read(map, MT6323_EFUSE_DOUT_BASE + offset + i, &tmp);
+		if (ret)
+			return ret;
+
+		*buf++ = tmp;
+	}
+
+	return 0;
+}
+
+static int mt6323_efuse_probe(struct platform_device *pdev)
+{
+	struct mt6397_chip *mt6323 = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	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;
+
+	if (!mt6323 || !mt6323->regmap)
+		return dev_err_probe(dev, -ENODEV, "failed to get parent\n");
+
+	config.dev = dev;
+	config.priv = mt6323->regmap;
+
+	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" },
+	{ }
+};
+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");

-- 
2.55.0

[PATCH v5 3/3] ARM: dts: mediatek: mt6323: add EFUSE support

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@protonmail.com>

Add the devicetree node for the mt6323 efuse.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 arch/arm/boot/dts/mediatek/mt6323.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/mediatek/mt6323.dtsi b/arch/arm/boot/dts/mediatek/mt6323.dtsi
index c070f4b0936c..c2d08d29cee7 100644
--- a/arch/arm/boot/dts/mediatek/mt6323.dtsi
+++ b/arch/arm/boot/dts/mediatek/mt6323.dtsi
@@ -19,6 +19,10 @@ mt6323_adc: adc {
 			#io-channel-cells = <1>;
 		};
 
+		efuse {
+			compatible = "mediatek,mt6323-efuse";
+		};
+
 		mt6323_leds: leds {
 			compatible = "mediatek,mt6323-led";
 			#address-cells = <1>;

-- 
2.55.0

[PATCH v5 3/3] ARM: dts: mediatek: mt6323: add EFUSE support

[Roman Vivchar]

Add the devicetree node for the mt6323 efuse.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 arch/arm/boot/dts/mediatek/mt6323.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/mediatek/mt6323.dtsi b/arch/arm/boot/dts/mediatek/mt6323.dtsi
index c070f4b0936c..c2d08d29cee7 100644
--- a/arch/arm/boot/dts/mediatek/mt6323.dtsi
+++ b/arch/arm/boot/dts/mediatek/mt6323.dtsi
@@ -19,6 +19,10 @@ mt6323_adc: adc {
 			#io-channel-cells = <1>;
 		};
 
+		efuse {
+			compatible = "mediatek,mt6323-efuse";
+		};
+
 		mt6323_leds: leds {
 			compatible = "mediatek,mt6323-led";
 			#address-cells = <1>;

-- 
2.55.0

Re: [PATCH v5 2/3] nvmem: add mt6323 PMIC EFUSE driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
- [High] nvmem: buffer overflow and unaligned memory access in efuse read loop
- [Medium] nvmem: EFUSE data exposed with host-dependent endianness
- [Medium] nvmem: NULL pointer dereference in probe when parent is missing
- [Medium] nvmem: module autoloading fails without MODULE_ALIAS
--

commit 3543415716c7fda0e6f5e6edb62e4ed761b35afd
Author: Roman Vivchar <rva333@protonmail.com>

nvmem: add mt6323 PMIC EFUSE driver

This commit adds 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.

diff --git a/drivers/nvmem/mt6323-efuse.c b/drivers/nvmem/mt6323-efuse.c
new file mode 100644
index 0000000000000..de5e30215c22d
--- /dev/null
+++ b/drivers/nvmem/mt6323-efuse.c
[ ... ]
> +static int mt6323_efuse_read(void *context, unsigned int offset, void *val,
> +			     size_t bytes)
> +{
> +	struct regmap *map = context;
> +	u16 *buf = val;
> +	u32 tmp;
> +	int ret;
> +
> +	/*
> +	 * A manual loop using regmap_read is required because PWRAP is not
> +	 * a continuous MMIO space, but rather a FSM that doesn't implement the
> +	 * necessary read callback for the regmap_read_raw and regmap_read_bulk
> +	 * functions.
> +	 */
> +	for (size_t i = 0; i < bytes; i += sizeof(*buf)) {

[Severity: High]
Could this loop overflow the allocated val buffer and cause unaligned memory
accesses?

The NVMEM core API nvmem_device_read() does not enforce that the requested
bytes count is a multiple of word_size. If an in-kernel consumer requests an
odd number of bytes (for example, 1 or 3), the loop will run an extra
iteration and unconditionally write a full 16-bit word. This will overflow
the caller's allocated val buffer by 1 byte.

Additionally, if val is not 16-bit aligned, this causes an unaligned memory
access.

> +		ret = regmap_read(map, MT6323_EFUSE_DOUT_BASE + offset + i, &tmp);
> +		if (ret)
> +			return ret;
> +
> +		*buf++ = tmp;

[Severity: Medium]
Does this expose the EFUSE data with a host-dependent endianness?

The regmap_read() function returns a CPU-endian 32-bit integer, which is
assigned to tmp. Writing this integer into a 16-bit buffer using native CPU
byte order means that on big-endian architectures, the bytes will be swapped
compared to little-endian architectures, breaking the expected NVMEM byte
stream consistency.

> +	}
> +
> +	return 0;
> +}
> +
> +static int mt6323_efuse_probe(struct platform_device *pdev)
> +{
> +	struct mt6397_chip *mt6323 = dev_get_drvdata(pdev->dev.parent);

[Severity: Medium]
Will this cause a NULL pointer dereference if the parent device pointer is
missing?

The driver has an of_match_table. If it is instantiated directly from a root
Device Tree node rather than being instantiated as an MFD child, the parent
device pointer pdev->dev.parent will be NULL. Calling dev_get_drvdata() on a
NULL parent dereferences it immediately without checks, leading to a crash.

[ ... ]
> +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");

[Severity: Medium]
Will module autoloading fail without a MODULE_ALIAS declaration here?

On systems where the Device Tree lacks the mediatek,mt6323-efuse node, the
MFD core will still instantiate the child device by name, producing a modalias
of platform:mt6323-efuse. Because the driver lacks a MODULE_ALIAS declaration
for platform:mt6323-efuse, udev cannot match the modalias, and the module
might never be automatically loaded on boot.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260921-mt6323-nvmem-v5-0-2f5d308369f0@protonmail.com?part=2

Re: (subset) [PATCH v5 0/3] nvmem: add support for the MediaTek mt6323 PMIC

[Srinivas Kandagatla]

On Mon, 21 Sep 2026 10:50:01 +0300, Roman Vivchar wrote:
> This series adds support for the EFUSE found on the MediaTek mt6323 PMIC.
> 
> Tested on the MediaTek mt6572 and mt8163 SoCs (Ben), both paired with a
> mt6323.
> 
> 

Applied, thanks!

[1/3] dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE
      commit: c29abe7af10aa891da6c0b68274258232ee3a1a7
[2/3] nvmem: add mt6323 PMIC EFUSE driver
      commit: 70a3d85e936cb43165331b9ea470b311a5beeeaa

Best regards,
-- 
Srinivas Kandagatla <srini@kernel.org>