[PATCH 0/4] AUXADC driver for the MediaTek mt6323 PMIC

[PATCH 0/4] AUXADC driver for the MediaTek mt6323 PMIC

[Roman Vivchar via B4 Relay]

This series adds support for the 15-bit AUXADC hardware block 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.

The other parts (EFUSE and thermal) will probably be sent next week.

[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 after split:
- dt-bindings: Change 'MT63xx' to 'MT6350 series and similar' (Jonathan)
- AUXADC driver:
    - Add missing headers (Andy)
    - Fix AUXADC_TRIM_CH* values (Andy)
    - Rename masks to include their register name (Jonathan)
    - Fix formatting (Andy, Jonathan)
    - Replace channel address with actual register value (Jonathan), align the table
    - Replace IIO_TEMP with IIO_VOLTAGE, since the actual output is still mV, not mC
    - Rename constants to match their registers (Jonathan)
    - Remove 'if/else if/else' in the mt6323_auxadc_read_raw (Andy)
    - Add comments for fsleep, ADC range and resolution (Andy, Jonathan)
    - Remove useless error messages (Andy)
- Maintainers:
    - Explicitly include mt6323 in the name (Jonathan)
    - Squash with AUXADC driver commit (Krzysztof)
    - Set status back to 'Maintained'
- Link to a previous series: https://patch.msgid.link/20260512-mt6323-v2-0-3efcba579e88@protonmail.com

---
Roman Vivchar (4):
      dt-bindings: iio: adc: mediatek,mt6359-auxadc: add mt6323 PMIC AUXADC
      iio: adc: mt6323-auxadc: add mt6323 PMIC AUXADC driver
      mfd: mt6397-core: add mt6323 AUXADC support
      ARM: dts: mediatek: mt6323: add AUXADC support

 .../bindings/iio/adc/mediatek,mt6359-auxadc.yaml   |   3 +-
 MAINTAINERS                                        |   8 +
 arch/arm/boot/dts/mediatek/mt6323.dtsi             |   5 +
 drivers/iio/adc/Kconfig                            |  11 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/mt6323-auxadc.c                    | 299 +++++++++++++++++++++
 drivers/mfd/mt6397-core.c                          |   3 +
 .../dt-bindings/iio/adc/mediatek,mt6323-auxadc.h   |  24 ++
 8 files changed, 353 insertions(+), 1 deletion(-)
---
base-commit: 028ef9c96e96197026887c0f092424679298aae8
change-id: 20260525-mt6323-adc-3befce36cbf2

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

[PATCH 1/4] dt-bindings: iio: adc: mediatek,mt6359-auxadc: add mt6323 PMIC AUXADC

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@protonmail.com>

The MediaTek mt6323 PMIC includes an AUXADC used for battery voltage,
temperature, and other internal measurements.

Add the devicetree binding documentation and the associated header file
defining the ADC channel constants.

Also change the description to the 'MT6350 series and similar' because
the binding already includes more than mt635x series PMICs.

Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 .../bindings/iio/adc/mediatek,mt6359-auxadc.yaml   |  3 ++-
 .../dt-bindings/iio/adc/mediatek,mt6323-auxadc.h   | 24 ++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/mediatek,mt6359-auxadc.yaml b/Documentation/devicetree/bindings/iio/adc/mediatek,mt6359-auxadc.yaml
index 5d4ab701f51a..852eb7336a5a 100644
--- a/Documentation/devicetree/bindings/iio/adc/mediatek,mt6359-auxadc.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/mediatek,mt6359-auxadc.yaml
@@ -4,7 +4,7 @@
 $id: http://devicetree.org/schemas/iio/adc/mediatek,mt6359-auxadc.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: MediaTek MT6350 series PMIC AUXADC
+title: MediaTek MT6350 series and similar PMIC AUXADC
 
 maintainers:
   - AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
@@ -19,6 +19,7 @@ description:
 properties:
   compatible:
     enum:
+      - mediatek,mt6323-auxadc
       - mediatek,mt6357-auxadc
       - mediatek,mt6358-auxadc
       - mediatek,mt6359-auxadc
diff --git a/include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h b/include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h
new file mode 100644
index 000000000000..6ee9a9ecffc1
--- /dev/null
+++ b/include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+
+#ifndef _DT_BINDINGS_MEDIATEK_MT6323_AUXADC_H
+#define _DT_BINDINGS_MEDIATEK_MT6323_AUXADC_H
+
+#define MT6323_AUXADC_BATON2		0
+#define MT6323_AUXADC_CH6		1
+#define MT6323_AUXADC_BAT_TEMP		2
+#define MT6323_AUXADC_CHIP_TEMP		3
+#define MT6323_AUXADC_VCDT		4
+#define MT6323_AUXADC_BATON1		5
+#define MT6323_AUXADC_ISENSE		6
+#define MT6323_AUXADC_BATSNS		7
+#define MT6323_AUXADC_ACCDET		8
+#define MT6323_AUXADC_AUDIO0		9
+#define MT6323_AUXADC_AUDIO1		10
+#define MT6323_AUXADC_AUDIO2		11
+#define MT6323_AUXADC_AUDIO3		12
+#define MT6323_AUXADC_AUDIO4		13
+#define MT6323_AUXADC_AUDIO5		14
+#define MT6323_AUXADC_AUDIO6		15
+#define MT6323_AUXADC_AUDIO7		16
+
+#endif

-- 
2.54.0

Re: [PATCH 1/4] dt-bindings: iio: adc: mediatek,mt6359-auxadc: add mt6323 PMIC AUXADC

[Conor Dooley]

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Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

[-- Attachment #2: signature.asc --]
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[PATCH 2/4] iio: adc: mt6323-auxadc: add mt6323 PMIC AUXADC driver

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@protonmail.com>

The mt6323 AUXADC is a 15-bit ADC used for system monitoring. This driver
provides support for reading various channels including battery and
charger voltages, battery and chip temperature, current sensing and
accessory detection.

Add a driver for the AUXADC found in the MediaTek mt6323 PMIC.

Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
Signed-off-by: Roman Vivchar <rva333@protonmail.com>
---
 MAINTAINERS                     |   8 ++
 drivers/iio/adc/Kconfig         |  11 ++
 drivers/iio/adc/Makefile        |   1 +
 drivers/iio/adc/mt6323-auxadc.c | 299 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 319 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index d1cc0e12fe1f..c9ad2417a3ef 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16256,6 +16256,14 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/mmc/mtk-sd.yaml
 F:	drivers/mmc/host/mtk-sd.c
 
+MEDIATEK MT6323 PMIC AUXADC DRIVER
+M:	Roman Vivchar <rva333@protonmail.com>
+L:	linux-iio@vger.kernel.org
+L:	linux-mediatek@lists.infradead.org (moderated for non-subscribers)
+S:	Maintained
+F:	drivers/iio/adc/mt6323-auxadc.c
+F:	include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h
+
 MEDIATEK MT6735 CLOCK & RESET DRIVERS
 M:	Yassine Oudjana <y.oudjana@protonmail.com>
 L:	linux-clk@vger.kernel.org
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 60038ae8dfc4..a03614b46041 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1137,6 +1137,17 @@ config MCP3911
 	  This driver can also be built as a module. If so, the module will be
 	  called mcp3911.
 
+config MEDIATEK_MT6323_AUXADC
+	tristate "MediaTek MT6323 PMIC AUXADC driver"
+	depends on MFD_MT6397
+	help
+	  Say yes here to enable support for MediaTek MT6323 PMIC Auxiliary ADC.
+	  This driver provides multiple channels for system monitoring,
+	  such as battery voltage, PMIC temperature, and others.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called mt6323-auxadc.
+
 config MEDIATEK_MT6359_AUXADC
 	tristate "MediaTek MT6359 PMIC AUXADC driver"
 	depends on MFD_MT6397
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index c76550415ff1..58161750d6e3 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_MCP320X) += mcp320x.o
 obj-$(CONFIG_MCP3422) += mcp3422.o
 obj-$(CONFIG_MCP3564) += mcp3564.o
 obj-$(CONFIG_MCP3911) += mcp3911.o
+obj-$(CONFIG_MEDIATEK_MT6323_AUXADC) += mt6323-auxadc.o
 obj-$(CONFIG_MEDIATEK_MT6359_AUXADC) += mt6359-auxadc.o
 obj-$(CONFIG_MEDIATEK_MT6360_ADC) += mt6360-adc.o
 obj-$(CONFIG_MEDIATEK_MT6370_ADC) += mt6370-adc.o
diff --git a/drivers/iio/adc/mt6323-auxadc.c b/drivers/iio/adc/mt6323-auxadc.c
new file mode 100644
index 000000000000..da6c11a5079c
--- /dev/null
+++ b/drivers/iio/adc/mt6323-auxadc.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2026 Roman Vivchar <rva333@protonmail.com>
+ *
+ * Based on drivers/iio/adc/mt6359-auxadc.c
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/stringify.h>
+#include <linux/time.h>
+#include <linux/types.h>
+
+#include <linux/mfd/mt6323/registers.h>
+
+#include <dt-bindings/iio/adc/mediatek,mt6323-auxadc.h>
+
+#define AUXADC_STRUP_CON10_RSTB_SEL	BIT(7)
+#define AUXADC_STRUP_CON10_RSTB_SW	BIT(5)
+
+#define AUXADC_TOP_CKPDN2_CTL_CK	BIT(5)
+
+#define AUXADC_TRIM_CH2_MASK		GENMASK(11, 10)
+#define AUXADC_TRIM_CH4_MASK		GENMASK(9, 8)
+#define AUXADC_TRIM_CH5_MASK		GENMASK(5, 4)
+#define AUXADC_TRIM_CH6_MASK		GENMASK(3, 2)
+
+#define AUXADC_CON27_VREF18_ENB_MD	BIT(15)
+#define AUXADC_CON27_MD_STATUS		BIT(0)
+
+#define AUXADC_CON19_GPS_STATUS		BIT(1)
+
+#define AUXADC_CON26_VREF18_SELB	BIT(1)
+#define AUXADC_CON26_DECI_GDLY_SEL	BIT(0)
+
+#define AUXADC_CON11_VBUF_EN		BIT(4)
+
+#define AUXADC_CON19_DECI_GDLY_MASK	GENMASK(15, 14)
+#define AUXADC_ADC19_BUSY_MASK		GENMASK(15, 1)
+#define AUXADC_READY_MASK		BIT(15)
+#define AUXADC_DATA_MASK		GENMASK(14, 0)
+
+#define AUXADC_CON9_OSR_MASK		GENMASK(12, 10)
+#define AUXADC_DEFAULT_OSR		3
+
+#define AUXADC_LOW_CHANNEL_MASK		GENMASK(9, 0)
+#define AUXADC_AUDIO_CHANNEL_MASK	GENMASK(8, 0)
+
+#define MTK_PMIC_IIO_CHAN(_name, _chan, _addr, _ch_type)        \
+{                                                               \
+	.type = _ch_type,                                       \
+	.indexed = 1,                                           \
+	.channel = _chan,                                       \
+	.address = _addr,                                       \
+	.datasheet_name = __stringify(_name),                   \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
+			      BIT(IIO_CHAN_INFO_SCALE),         \
+}
+
+static const struct iio_chan_spec mt6323_auxadc_channels[] = {
+	MTK_PMIC_IIO_CHAN(baton2,    MT6323_AUXADC_BATON2,    MT6323_AUXADC_ADC6,  IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(ch6,       MT6323_AUXADC_CH6,       MT6323_AUXADC_ADC11, IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(bat_temp,  MT6323_AUXADC_BAT_TEMP,  MT6323_AUXADC_ADC5,  IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(chip_temp, MT6323_AUXADC_CHIP_TEMP, MT6323_AUXADC_ADC4,  IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(vcdt,      MT6323_AUXADC_VCDT,      MT6323_AUXADC_ADC2,  IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(baton1,    MT6323_AUXADC_BATON1,    MT6323_AUXADC_ADC3,  IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(isense,    MT6323_AUXADC_ISENSE,    MT6323_AUXADC_ADC1,  IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(batsns,    MT6323_AUXADC_BATSNS,    MT6323_AUXADC_ADC0,  IIO_VOLTAGE),
+	MTK_PMIC_IIO_CHAN(accdet,    MT6323_AUXADC_ACCDET,    MT6323_AUXADC_ADC7,  IIO_VOLTAGE),
+};
+
+/**
+ * struct mt6323_auxadc - Main driver structure
+ * @regmap:        Regmap from PWRAP
+ * @lock:          Mutex to serialize AUXADC reading vs configuration
+ *
+ * The MediaTek MT6323 (as well as a lot of other PMICs) has the following hierarchy:
+ * PMIC AUXADC <- PMIC MFD <- SoC PWRAP (wrapper for PWRAP FSM)
+ *
+ * Therefore, PWRAP regmap should be obtained using dev->parent->parent.
+ */
+struct mt6323_auxadc {
+	struct regmap *regmap;
+	struct mutex lock;
+};
+
+static int mt6323_auxadc_prepare_channel(struct mt6323_auxadc *auxadc)
+{
+	struct regmap *map = auxadc->regmap;
+	u32 val;
+	int ret;
+
+	ret = regmap_read(map, MT6323_AUXADC_CON19, &val);
+	if (ret)
+		return ret;
+
+	/* The ADC is idle. */
+	if (!(val & AUXADC_CON19_DECI_GDLY_MASK))
+		return 0;
+
+	ret = regmap_read_poll_timeout(map, MT6323_AUXADC_ADC19, val,
+				       !(val & AUXADC_ADC19_BUSY_MASK),
+				       10, 500);
+	if (ret)
+		return ret;
+
+	return regmap_clear_bits(map, MT6323_AUXADC_CON19,
+				 AUXADC_CON19_DECI_GDLY_MASK);
+}
+
+static int mt6323_auxadc_request(struct mt6323_auxadc *auxadc,
+				 unsigned long channel)
+{
+	struct regmap *map = auxadc->regmap;
+	int ret;
+
+	ret = regmap_set_bits(map, MT6323_AUXADC_CON11, AUXADC_CON11_VBUF_EN);
+	if (ret)
+		return ret;
+
+	ret = regmap_clear_bits(map, MT6323_AUXADC_CON22, BIT(channel));
+	if (ret)
+		return ret;
+
+	return regmap_set_bits(map, MT6323_AUXADC_CON22, BIT(channel));
+}
+
+static int mt6323_auxadc_read(struct mt6323_auxadc *auxadc,
+			      const struct iio_chan_spec *chan, int *out)
+{
+	struct regmap *map = auxadc->regmap;
+	u32 reg = chan->address;
+	u32 val;
+	int ret;
+
+	ret = regmap_read_poll_timeout(map, reg, val, (val & AUXADC_READY_MASK),
+				       1 * USEC_PER_MSEC, 100 * USEC_PER_MSEC);
+	if (ret)
+		return ret;
+
+	*out = FIELD_GET(AUXADC_DATA_MASK, val);
+
+	return 0;
+}
+
+static int mt6323_auxadc_read_raw(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan,
+				  int *val, int *val2, long mask)
+{
+	struct mt6323_auxadc *auxadc = iio_priv(indio_dev);
+	int ret, mult;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->channel == MT6323_AUXADC_ISENSE ||
+		    chan->channel == MT6323_AUXADC_BATSNS)
+			mult = 4;
+		else
+			mult = 1;
+
+		/* 1800mV full range with 15-bit resolution. */
+		*val = mult * 1800;
+		*val2 = 15;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
+	case IIO_CHAN_INFO_RAW:
+		scoped_guard(mutex, &auxadc->lock) {
+			ret = mt6323_auxadc_prepare_channel(auxadc);
+			if (ret)
+				return ret;
+
+			ret = mt6323_auxadc_request(auxadc, chan->channel);
+			if (ret)
+				return ret;
+
+			/* Hardware limitation: the AUXADC needs a delay to become ready. */
+			fsleep(300);
+
+			ret = mt6323_auxadc_read(auxadc, chan, val);
+			if (ret)
+				return ret;
+		}
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mt6323_auxadc_init(struct mt6323_auxadc *auxadc)
+{
+	struct regmap *map = auxadc->regmap;
+	int ret;
+
+	ret = regmap_set_bits(map, MT6323_STRUP_CON10,
+			      AUXADC_STRUP_CON10_RSTB_SW |
+			      AUXADC_STRUP_CON10_RSTB_SEL);
+	if (ret)
+		return ret;
+
+	ret = regmap_set_bits(map, MT6323_TOP_CKPDN2, AUXADC_TOP_CKPDN2_CTL_CK);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(map, MT6323_AUXADC_CON10,
+				 AUXADC_TRIM_CH2_MASK | AUXADC_TRIM_CH4_MASK |
+				 AUXADC_TRIM_CH5_MASK | AUXADC_TRIM_CH6_MASK,
+				 FIELD_PREP(AUXADC_TRIM_CH2_MASK, 1) |
+				 FIELD_PREP(AUXADC_TRIM_CH4_MASK, 1) |
+				 FIELD_PREP(AUXADC_TRIM_CH5_MASK, 1) |
+				 FIELD_PREP(AUXADC_TRIM_CH6_MASK, 1));
+	if (ret)
+		return ret;
+
+	ret = regmap_set_bits(map, MT6323_AUXADC_CON27,
+			      AUXADC_CON27_VREF18_ENB_MD |
+			      AUXADC_CON27_MD_STATUS);
+	if (ret)
+		return ret;
+
+	ret = regmap_set_bits(map, MT6323_AUXADC_CON19, AUXADC_CON19_GPS_STATUS);
+	if (ret)
+		return ret;
+
+	ret = regmap_set_bits(map, MT6323_AUXADC_CON26,
+			      AUXADC_CON26_VREF18_SELB |
+			      AUXADC_CON26_DECI_GDLY_SEL);
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(map, MT6323_AUXADC_CON9, AUXADC_CON9_OSR_MASK,
+				  FIELD_PREP(AUXADC_CON9_OSR_MASK, AUXADC_DEFAULT_OSR));
+}
+
+static const struct iio_info mt6323_auxadc_iio_info = {
+	.read_raw = mt6323_auxadc_read_raw,
+};
+
+static int mt6323_auxadc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mt6323_auxadc *auxadc;
+	struct iio_dev *iio;
+	struct regmap *regmap;
+	int ret;
+
+	regmap = dev_get_regmap(dev->parent->parent, NULL);
+	if (!regmap)
+		return dev_err_probe(dev, -ENODEV, "failed to get regmap\n");
+
+	iio = devm_iio_device_alloc(dev, sizeof(*auxadc));
+	if (!iio)
+		return -ENOMEM;
+
+	auxadc = iio_priv(iio);
+	auxadc->regmap = regmap;
+
+	ret = devm_mutex_init(dev, &auxadc->lock);
+	if (ret)
+		return ret;
+
+	ret = mt6323_auxadc_init(auxadc);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to initialize auxadc\n");
+
+	iio->name = "mt6323-auxadc";
+	iio->info = &mt6323_auxadc_iio_info;
+	iio->modes = INDIO_DIRECT_MODE;
+	iio->channels = mt6323_auxadc_channels;
+	iio->num_channels = ARRAY_SIZE(mt6323_auxadc_channels);
+
+	return devm_iio_device_register(dev, iio);
+}
+
+static const struct of_device_id mt6323_auxadc_of_match[] = {
+	{ .compatible = "mediatek,mt6323-auxadc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mt6323_auxadc_of_match);
+
+static struct platform_driver mt6323_auxadc_driver = {
+	.driver = {
+		.name = "mt6323-auxadc",
+		.of_match_table = mt6323_auxadc_of_match,
+	},
+	.probe	= mt6323_auxadc_probe,
+};
+module_platform_driver(mt6323_auxadc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MediaTek MT6323 PMIC AUXADC Driver");

-- 
2.54.0

Re: [PATCH 2/4] iio: adc: mt6323-auxadc: add mt6323 PMIC AUXADC driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Unchecked pointer dereference of `dev->parent` and `dev->parent->parent` when fetching the PMIC wrapper regmap.
- [High] Channel interference and power leak due to missing teardown of active channels and voltage buffer.
--

commit 3ea46406f2075e002ef31a93fd209e78c86e9790
Author: Roman Vivchar <rva333@protonmail.com>

iio: adc: mt6323-auxadc: add mt6323 PMIC AUXADC driver

The mt6323 AUXADC is a 15-bit ADC used for system monitoring. This driver
provides support for reading various channels including battery and
charger voltages, battery and chip temperature, current sensing and
accessory detection.
    
Add a driver for the AUXADC found in the MediaTek mt6323 PMIC.

> diff --git a/drivers/iio/adc/mt6323-auxadc.c b/drivers/iio/adc/mt6323-auxadc.c
> new file mode 100644
> index 0000000000000..da6c11a5079c0
> --- /dev/null
> +++ b/drivers/iio/adc/mt6323-auxadc.c
[ ... ]
> +static int mt6323_auxadc_request(struct mt6323_auxadc *auxadc,
> +				 unsigned long channel)
> +{
> +	struct regmap *map = auxadc->regmap;
> +	int ret;
> +
> +	ret = regmap_set_bits(map, MT6323_AUXADC_CON11, AUXADC_CON11_VBUF_EN);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_clear_bits(map, MT6323_AUXADC_CON22, BIT(channel));
> +	if (ret)
> +		return ret;
> +
> +	return regmap_set_bits(map, MT6323_AUXADC_CON22, BIT(channel));
> +}

[Severity: High]
Does this leave previously requested channels active in MT6323_AUXADC_CON22?

Since it only clears and sets the bit for the currently requested channel,
multiple channel bits could accumulate in the register over time. Could this
cause hardware contention or mixed readings when channels are used
sequentially?

[ ... ]
> +static int mt6323_auxadc_read_raw(struct iio_dev *indio_dev,
> +				  const struct iio_chan_spec *chan,
> +				  int *val, int *val2, long mask)
> +{
> +	struct mt6323_auxadc *auxadc = iio_priv(indio_dev);
> +	int ret, mult;
> +
> +	switch (mask) {
[ ... ]
> +	case IIO_CHAN_INFO_RAW:
> +		scoped_guard(mutex, &auxadc->lock) {
> +			ret = mt6323_auxadc_prepare_channel(auxadc);
> +			if (ret)
> +				return ret;
> +
> +			ret = mt6323_auxadc_request(auxadc, chan->channel);
> +			if (ret)
> +				return ret;
> +
> +			/* Hardware limitation: the AUXADC needs a delay to become ready. */
> +			fsleep(300);
> +
> +			ret = mt6323_auxadc_read(auxadc, chan, val);
> +			if (ret)
> +				return ret;
> +		}
> +		return IIO_VAL_INT;

[Severity: High]
Does this leak power by leaving AUXADC_CON11_VBUF_EN enabled after the
reading finishes?

It appears the voltage buffer is enabled in mt6323_auxadc_request() but never
disabled once the conversion completes and exits here. Also, the active
channel is never cleared.

[ ... ]
> +static int mt6323_auxadc_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct mt6323_auxadc *auxadc;
> +	struct iio_dev *iio;
> +	struct regmap *regmap;
> +	int ret;
> +
> +	regmap = dev_get_regmap(dev->parent->parent, NULL);

[Severity: High]
Is it possible for dev->parent->parent to be NULL here?

If this driver is instantiated directly via a Device Tree node (because of
its of_match_table) rather than as an MFD child, dev->parent would evaluate
to the platform_bus, making dev->parent->parent NULL.

Passing NULL to dev_get_regmap() causes an immediate kernel panic in
devres_find() when it attempts to acquire a spinlock. Should we verify the
parent hierarchy before dereferencing it?

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260602-mt6323-adc-v1-0-68ec737508ee@protonmail.com?part=2

Re: [PATCH 2/4] iio: adc: mt6323-auxadc: add mt6323 PMIC AUXADC driver

[Nuno Sá]

On Tue, 2026-06-02 at 15:46 +0300, Roman Vivchar via B4 Relay wrote:
> From: Roman Vivchar <rva333@protonmail.com>
> 
> The mt6323 AUXADC is a 15-bit ADC used for system monitoring. This driver
> provides support for reading various channels including battery and
> charger voltages, battery and chip temperature, current sensing and
> accessory detection.
> 
> Add a driver for the AUXADC found in the MediaTek mt6323 PMIC.
> 
> Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd
> Generation)
> Signed-off-by: Roman Vivchar <rva333@protonmail.com>
> ---
>  MAINTAINERS                     |   8 ++
>  drivers/iio/adc/Kconfig         |  11 ++
>  drivers/iio/adc/Makefile        |   1 +
>  drivers/iio/adc/mt6323-auxadc.c | 299 ++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 319 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d1cc0e12fe1f..c9ad2417a3ef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16256,6 +16256,14 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/mmc/mtk-sd.yaml
>  F:	drivers/mmc/host/mtk-sd.c
>  
> +MEDIATEK MT6323 PMIC AUXADC DRIVER
> +M:	Roman Vivchar <rva333@protonmail.com>
> +L:	linux-iio@vger.kernel.org
> +L:	linux-mediatek@lists.infradead.org (moderated for non-subscribers)
> +S:	Maintained
> +F:	drivers/iio/adc/mt6323-auxadc.c
> +F:	include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h

The above file was not added in this patch

...

> +
> +static const struct iio_chan_spec mt6323_auxadc_channels[] = {
> +	MTK_PMIC_IIO_CHAN(baton2,    MT6323_AUXADC_BATON2,    MT6323_AUXADC_ADC6, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(ch6,       MT6323_AUXADC_CH6,       MT6323_AUXADC_ADC11,
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(bat_temp,  MT6323_AUXADC_BAT_TEMP,  MT6323_AUXADC_ADC5, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(chip_temp, MT6323_AUXADC_CHIP_TEMP, MT6323_AUXADC_ADC4, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(vcdt,      MT6323_AUXADC_VCDT,      MT6323_AUXADC_ADC2, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(baton1,    MT6323_AUXADC_BATON1,    MT6323_AUXADC_ADC3, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(isense,    MT6323_AUXADC_ISENSE,    MT6323_AUXADC_ADC1, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(batsns,    MT6323_AUXADC_BATSNS,    MT6323_AUXADC_ADC0, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(accdet,    MT6323_AUXADC_ACCDET,    MT6323_AUXADC_ADC7, 
> IIO_VOLTAGE),
> +};

All of the above are IIO_VOLTAGE. Just remove _ch_type then.

> +
> +/**
> + * struct mt6323_auxadc - Main driver structure
> + * @regmap:        Regmap from PWRAP
> + * @lock:          Mutex to serialize AUXADC reading vs configuration
> + *
> + * The MediaTek MT6323 (as well as a lot of other PMICs) has the following
> hierarchy:
> + * PMIC AUXADC <- PMIC MFD <- SoC PWRAP (wrapper for PWRAP FSM)
> + *
> + * Therefore, PWRAP regmap should be obtained using dev->parent->parent.
> + */

The above kerneldoc seems unnecessary to me.

> +struct mt6323_auxadc {
> +	struct regmap *regmap;
> +	struct mutex lock;
> +};

...

> 
> +
> +static int mt6323_auxadc_read_raw(struct iio_dev *indio_dev,
> +				  const struct iio_chan_spec *chan,
> +				  int *val, int *val2, long mask)
> +{
> +	struct mt6323_auxadc *auxadc = iio_priv(indio_dev);
> +	int ret, mult;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		if (chan->channel == MT6323_AUXADC_ISENSE ||
> +		    chan->channel == MT6323_AUXADC_BATSNS)
> +			mult = 4;
> +		else
> +			mult = 1;
> +
> +		/* 1800mV full range with 15-bit resolution. */
> +		*val = mult * 1800;
> +		*val2 = 15;
> +
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	case IIO_CHAN_INFO_RAW:
> +		scoped_guard(mutex, &auxadc->lock) {
> +			ret = mt6323_auxadc_prepare_channel(auxadc);
> +			if (ret)
> +				return ret;
> +
> +			ret = mt6323_auxadc_request(auxadc, chan->channel);
> +			if (ret)
> +				return ret;
> +
> +			/* Hardware limitation: the AUXADC needs a delay to become
> ready. */
> +			fsleep(300);
> +
> +			ret = mt6323_auxadc_read(auxadc, chan, val);
> +			if (ret)
> +				return ret;

Could be return mt6323_auxadc_read(...)

- Nuno Sá
> 
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("MediaTek MT6323 PMIC AUXADC Driver");

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

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@protonmail.com>

The mt6323 PMIC includes an AUXADC. Register the AUXADC 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..013b0857fb54 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-auxadc",
+		.of_compatible = "mediatek,mt6323-auxadc",
+	}, {
 		.name = "mt6323-rtc",
 		.num_resources = ARRAY_SIZE(mt6323_rtc_resources),
 		.resources = mt6323_rtc_resources,

-- 
2.54.0

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

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unvalidated parent pointer dereference causes a kernel oops on invalid Device Tree.
--

commit d38d038f6b60f5f733b7e5174e9d4dc5a41d7cec
Author: Roman Vivchar <rva333@protonmail.com>

mfd: mt6397-core: add mt6323 AUXADC support

This commit registers the AUXADC in the mt6323 devices array to allow the
corresponding driver to probe using the newly added compatible string.

> diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
> index 3e58d0764c7e0..013b0857fb548 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-auxadc",
> +		.of_compatible = "mediatek,mt6323-auxadc",

[Severity: High]
Does adding this compatible string expose an unhandled edge case in the
auxadc driver?

If this device is instantiated directly from a Device Tree without an MFD
parent (e.g., at the DT root), dev->parent could be the platform bus
(which has a NULL parent) or NULL itself.

Looking at mt6323_auxadc_probe() in drivers/iio/adc/mt6323-auxadc.c:

    regmap = dev_get_regmap(dev->parent->parent, NULL);

Could blindly dereferencing dev->parent->parent here, or passing a NULL
device to dev_get_regmap() (which calls devres_find()), result in a
kernel oops if probed as a root node?

> +	}, {
>  		.name = "mt6323-rtc",
>  		.num_resources = ARRAY_SIZE(mt6323_rtc_resources),

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260602-mt6323-adc-v1-0-68ec737508ee@protonmail.com?part=3

[PATCH 4/4] ARM: dts: mediatek: mt6323: add AUXADC support

[Roman Vivchar via B4 Relay]

From: Roman Vivchar <rva333@protonmail.com>

Add the devicetree node for the mt6323 AUXADC.

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 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/boot/dts/mediatek/mt6323.dtsi b/arch/arm/boot/dts/mediatek/mt6323.dtsi
index c230c865116d..c070f4b0936c 100644
--- a/arch/arm/boot/dts/mediatek/mt6323.dtsi
+++ b/arch/arm/boot/dts/mediatek/mt6323.dtsi
@@ -14,6 +14,11 @@ pmic: mt6323 {
 		interrupt-controller;
 		#interrupt-cells = <2>;
 
+		mt6323_adc: adc {
+			compatible = "mediatek,mt6323-auxadc";
+			#io-channel-cells = <1>;
+		};
+
 		mt6323_leds: leds {
 			compatible = "mediatek,mt6323-led";
 			#address-cells = <1>;

-- 
2.54.0