[PATCH v2 0/4] nvmem: add support for the MediaTek mt6323 PMIC

[PATCH v2 0/4] 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.

The previous version of the series for all AUXADC, EFUSE and thermal
drivers was split after Krzysztof's comment [1].
    
Tested on the MediaTek mt6572 and mt8163 SoCs (Ben), both paired with a
mt6323.

[1]: https://lore.kernel.org/linux-mediatek/20260504-mt6323-v1-0-799b58b355ff@protonmail.com/T/#med30fad67a090be35f549231336b2dec295233f6

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@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 (4):
      dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE
      nvmem: add mt6323 PMIC EFUSE driver
      mfd: mt6397-core: add mt6323 EFUSE support
      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/mfd/mt6397-core.c                          |  3 +
 drivers/nvmem/Kconfig                              | 11 +++
 drivers/nvmem/Makefile                             |  2 +
 drivers/nvmem/mt6323-efuse.c                       | 85 ++++++++++++++++++++++
 7 files changed, 131 insertions(+)
---
base-commit: 028ef9c96e96197026887c0f092424679298aae8
change-id: 20260611-mt6323-nvmem-0c54a0f2fa9f

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

[PATCH v2 0/4] nvmem: add support for the MediaTek mt6323 PMIC

[Roman Vivchar]

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

The previous version of the series for all AUXADC, EFUSE and thermal
drivers was split after Krzysztof's comment [1].
    
Tested on the MediaTek mt6572 and mt8163 SoCs (Ben), both paired with a
mt6323.

[1]: https://lore.kernel.org/linux-mediatek/20260504-mt6323-v1-0-799b58b355ff@protonmail.com/T/#med30fad67a090be35f549231336b2dec295233f6

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@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 (4):
      dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE
      nvmem: add mt6323 PMIC EFUSE driver
      mfd: mt6397-core: add mt6323 EFUSE support
      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/mfd/mt6397-core.c                          |  3 +
 drivers/nvmem/Kconfig                              | 11 +++
 drivers/nvmem/Makefile                             |  2 +
 drivers/nvmem/mt6323-efuse.c                       | 85 ++++++++++++++++++++++
 7 files changed, 131 insertions(+)
---
base-commit: 028ef9c96e96197026887c0f092424679298aae8
change-id: 20260611-mt6323-nvmem-0c54a0f2fa9f

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

[PATCH v2 1/4] 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 05c121b0cb3d..beaa67bf0df2 100644
--- a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
+++ b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
@@ -145,6 +145,23 @@ 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
@@ -243,6 +260,10 @@ examples:
         interrupt-controller;
         #interrupt-cells = <2>;
 
+        efuse {
+          compatible = "mediatek,mt6323-efuse";
+        };
+
         leds {
             compatible = "mediatek,mt6323-led";
             #address-cells = <1>;

-- 
2.54.0

[PATCH v2 1/4] 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 05c121b0cb3d..beaa67bf0df2 100644
--- a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
+++ b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
@@ -145,6 +145,23 @@ 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
@@ -243,6 +260,10 @@ examples:
         interrupt-controller;
         #interrupt-cells = <2>;
 
+        efuse {
+          compatible = "mediatek,mt6323-efuse";
+        };
+
         leds {
             compatible = "mediatek,mt6323-led";
             #address-cells = <1>;

-- 
2.54.0

[PATCH v2 2/4] 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 | 85 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 103 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index d1cc0e12fe1f..910360f148c4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16256,6 +16256,11 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/mmc/mtk-sd.yaml
 F:	drivers/mmc/host/mtk-sd.c
 
+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 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..7a0ce4c7f565
--- /dev/null
+++ b/drivers/nvmem/mt6323-efuse.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2026 Roman Vivchar <rva333@protonmail.com>
+ */
+
+#include <linux/err.h>
+#include <linux/mod_devicetable.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 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;
+	struct regmap *regmap;
+
+	/* efuse -> mfd -> pwrap */
+	regmap = dev_get_regmap(dev->parent->parent, NULL);
+	if (!regmap)
+		return dev_err_probe(dev, -ENODEV, "failed to get regmap\n");
+
+	config.dev = dev;
+	config.priv = 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");

-- 
2.54.0

[PATCH v2 2/4] 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 | 85 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 103 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index d1cc0e12fe1f..910360f148c4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16256,6 +16256,11 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/mmc/mtk-sd.yaml
 F:	drivers/mmc/host/mtk-sd.c
 
+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 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..7a0ce4c7f565
--- /dev/null
+++ b/drivers/nvmem/mt6323-efuse.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2026 Roman Vivchar <rva333@protonmail.com>
+ */
+
+#include <linux/err.h>
+#include <linux/mod_devicetable.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 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;
+	struct regmap *regmap;
+
+	/* efuse -> mfd -> pwrap */
+	regmap = dev_get_regmap(dev->parent->parent, NULL);
+	if (!regmap)
+		return dev_err_probe(dev, -ENODEV, "failed to get regmap\n");
+
+	config.dev = dev;
+	config.priv = 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");

-- 
2.54.0

[PATCH v2 3/4] mfd: mt6397-core: add mt6323 EFUSE support

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@protonmail.com>

The mt6323 PMIC includes an EFUSE. Register the EFUSE in the mt6323
devices array to allow the corresponding driver to probe using compatible
string.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 drivers/mfd/mt6397-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
index 3e58d0764c7e..362737a1c4a9 100644
--- a/drivers/mfd/mt6397-core.c
+++ b/drivers/mfd/mt6397-core.c
@@ -125,6 +125,9 @@ static const struct resource mt6323_pwrc_resources[] = {
 
 static const struct mfd_cell mt6323_devs[] = {
 	{
+		.name = "mt6323-efuse",
+		.of_compatible = "mediatek,mt6323-efuse",
+	}, {
 		.name = "mt6323-rtc",
 		.num_resources = ARRAY_SIZE(mt6323_rtc_resources),
 		.resources = mt6323_rtc_resources,

-- 
2.54.0

[PATCH v2 3/4] mfd: mt6397-core: add mt6323 EFUSE support

[Roman Vivchar]

The mt6323 PMIC includes an EFUSE. Register the EFUSE in the mt6323
devices array to allow the corresponding driver to probe using compatible
string.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 drivers/mfd/mt6397-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
index 3e58d0764c7e..362737a1c4a9 100644
--- a/drivers/mfd/mt6397-core.c
+++ b/drivers/mfd/mt6397-core.c
@@ -125,6 +125,9 @@ static const struct resource mt6323_pwrc_resources[] = {
 
 static const struct mfd_cell mt6323_devs[] = {
 	{
+		.name = "mt6323-efuse",
+		.of_compatible = "mediatek,mt6323-efuse",
+	}, {
 		.name = "mt6323-rtc",
 		.num_resources = ARRAY_SIZE(mt6323_rtc_resources),
 		.resources = mt6323_rtc_resources,

-- 
2.54.0

[PATCH v2 4/4] 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 c230c865116d..807e000a7ff6 100644
--- a/arch/arm/boot/dts/mediatek/mt6323.dtsi
+++ b/arch/arm/boot/dts/mediatek/mt6323.dtsi
@@ -14,6 +14,10 @@ pmic: mt6323 {
 		interrupt-controller;
 		#interrupt-cells = <2>;
 
+		efuse {
+			compatible = "mediatek,mt6323-efuse";
+		};
+
 		mt6323_leds: leds {
 			compatible = "mediatek,mt6323-led";
 			#address-cells = <1>;

-- 
2.54.0

[PATCH v2 4/4] 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 c230c865116d..807e000a7ff6 100644
--- a/arch/arm/boot/dts/mediatek/mt6323.dtsi
+++ b/arch/arm/boot/dts/mediatek/mt6323.dtsi
@@ -14,6 +14,10 @@ pmic: mt6323 {
 		interrupt-controller;
 		#interrupt-cells = <2>;
 
+		efuse {
+			compatible = "mediatek,mt6323-efuse";
+		};
+
 		mt6323_leds: leds {
 			compatible = "mediatek,mt6323-led";
 			#address-cells = <1>;

-- 
2.54.0

Re: [PATCH v2 3/4] mfd: mt6397-core: add mt6323 EFUSE support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unchecked grandparent pointer dereference in mt6323_efuse_probe.
--

commit 9ff4fcd2490678b446194f62f1baf75c41828eff
Author: Roman Vivchar <rva333@protonmail.com>
Subject: mfd: mt6397-core: add mt6323 EFUSE support

This commit adds the mt6323 EFUSE to the mt6323 devices array in the MFD core.
This registration allows the corresponding efuse driver to probe using its
compatible string.

> diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
> index 3e58d0764c7e0..362737a1c4a9a 100644
> --- a/drivers/mfd/mt6397-core.c
> +++ b/drivers/mfd/mt6397-core.c
> @@ -125,6 +125,9 @@ static const struct resource mt6323_pwrc_resources[] = {
>  
>  static const struct mfd_cell mt6323_devs[] = {
>  	{
> +		.name = "mt6323-efuse",
> +		.of_compatible = "mediatek,mt6323-efuse",

[Severity: High]
Does adding this compatible string expose an unchecked pointer dereference
in the efuse driver?

Looking at mt6323_efuse_probe() in drivers/nvmem/mt6323-efuse.c:

mt6323_efuse_probe() {
    ...
    regmap = dev_get_regmap(dev->parent->parent, NULL);
    ...
}

If the driver is instantiated directly from a top-level device tree node via
this compatible string instead of as an MFD child, dev->parent will point to
the root platform bus. Because the platform bus has no parent,
dev->parent->parent evaluates to a NULL pointer.

Passing this NULL device pointer to dev_get_regmap() causes devres_find() to
unconditionally dereference it. Would it be safer to add a NULL check on
dev->parent and dev->parent->parent in the driver before doing this lookup
to prevent a kernel panic?

>  	}, {
>  		.name = "mt6323-rtc",

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260617-mt6323-nvmem-v2-0-4f30e36aa0f4@protonmail.com?part=3

Re: [PATCH v2 1/4] dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing core NVMEM schema reference for an NVMEM provider node.
--

commit 3b91c0fc686c29119bcba167256b72fe3a4c7b96
Author: Roman Vivchar <rva333@protonmail.com>
dt-bindings: mfd: mediatek: mt6397: add mt6323 PMIC EFUSE

This commit adds devicetree binding documentation for the MediaTek mt6323
EFUSE. The efuse component is responsible for storing calibration data
within the mt6323 PMIC.

> diff --git a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
> index 05c121b0cb3d8..beaa67bf0df2c 100644
> --- a/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
> +++ b/Documentation/devicetree/bindings/mfd/mediatek,mt6397.yaml
> @@ -145,6 +145,23 @@ 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#

[Severity: Low]
Does this node need a reference to the core NVMEM schema?

Because the efuse node acts as an NVMEM provider and uses 
unevaluatedProperties: false, it will currently reject standard NVMEM
properties like read-only and wp-gpios if they are specified in the
device tree.

Including a $ref to /schemas/nvmem/nvmem.yaml# would natively support
nvmem-layout and permit standard NVMEM provider features to pass validation.

> +
> +    required:
> +      - compatible
> +

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260617-mt6323-nvmem-v2-0-4f30e36aa0f4@protonmail.com?part=1

Re: [PATCH v2 4/4] ARM: dts: mediatek: mt6323: add EFUSE support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unchecked dereference of dev->parent when getting regmap.
--

commit f140540f16666ffd0b4a44edcb3b4ac15d83d749
Author: Roman Vivchar <rva333@protonmail.com>
ARM: dts: mediatek: mt6323: add EFUSE support

This commit adds the devicetree node for the mt6323 efuse to the mt6323
PMIC definition. It introduces the mediatek,mt6323-efuse compatible string
to instantiate the driver.

> diff --git a/arch/arm/boot/dts/mediatek/mt6323.dtsi b/arch/arm/boot/dts/mediatek/mt6323.dtsi
> index c230c865116d0..807e000a7ff64 100644
> --- a/arch/arm/boot/dts/mediatek/mt6323.dtsi
> +++ b/arch/arm/boot/dts/mediatek/mt6323.dtsi
> @@ -14,6 +14,10 @@ pmic: mt6323 {
>  		interrupt-controller;
>  		#interrupt-cells = <2>;
>  
> +		efuse {
> +			compatible = "mediatek,mt6323-efuse";

[Severity: High]
Does binding to this compatible string introduce a regression under certain
devicetree configurations?

Looking at drivers/nvmem/mt6323-efuse.c:mt6323_efuse_probe(), the driver
blindly traverses the parent hierarchy:

	/* efuse -> mfd -> pwrap */
	regmap = dev_get_regmap(dev->parent->parent, NULL);

If the device is instantiated directly at the root of a Device Tree
or via a malformed overlay, it lacks a grandparent. In this case,
dev->parent is initialized to &platform_bus, and evaluating
dev->parent->parent results in a null pointer.

Passing a null pointer as the device to dev_get_regmap() triggers an
immediate kernel panic during probe(), because the underlying
devres_find() unconditionally dereferences the dev pointer.

Could the driver verify that the parent hierarchy exists before
attempting to traverse it and retrieve the regmap?

> +		};
> +

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260617-mt6323-nvmem-v2-0-4f30e36aa0f4@protonmail.com?part=4

Re: [PATCH v2 2/4] nvmem: add mt6323 PMIC EFUSE driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Unchecked traversal of device parent pointers causes a NULL pointer dereference.
- [High] Buffer overflow in the NVMEM read callback for unaligned read requests.
--

commit 6d793839a1a7e502029cf9f7b58d011fec9486e7
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..7a0ce4c7f5658
> --- /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)) {
> +		ret = regmap_read(map, MT6323_EFUSE_DOUT_BASE + offset + i, &tmp);
> +		if (ret)
> +			return ret;
> +
> +		*buf++ = tmp;

[Severity: High]
What happens if an internal client requests to read an odd number of bytes?

Since this loop unconditionally writes a 16-bit word on each iteration, an odd
bytes length would cause the loop to execute an extra time and write past the
end of the destination buffer. Because nvmem_device_read() does not enforce
word_size alignment on internal requests, this could corrupt adjacent memory
if the caller allocated a buffer matching the exact requested size.

Could the driver explicitly reject unaligned lengths or safely handle partial
word writes?

> +	}
> +
> +	return 0;
> +}
> +
> +static int mt6323_efuse_probe(struct platform_device *pdev)
> +{
> +	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;
> +	struct regmap *regmap;
> +
> +	/* efuse -> mfd -> pwrap */
> +	regmap = dev_get_regmap(dev->parent->parent, NULL);

[Severity: High]
Could this lead to a NULL pointer dereference if the device tree hierarchy
is malformed?

If the device is instantiated at the top level or independently of the
expected MFD and PMIC wrapper structure, dev->parent could map to the
platform bus, making dev->parent->parent NULL. Passing a NULL pointer to
dev_get_regmap() will cause a kernel panic when it attempts to lock the
devres lock.

Would it be safer to verify that dev->parent and dev->parent->parent are
non-NULL before passing the grandparent pointer?

> +	if (!regmap)
> +		return dev_err_probe(dev, -ENODEV, "failed to get regmap\n");

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260617-mt6323-nvmem-v2-0-4f30e36aa0f4@protonmail.com?part=2