[PATCH v4 0/2] iio: adc: add Nuvoton NCT7201 ADC driver

[PATCH v4 0/2] iio: adc: add Nuvoton NCT7201 ADC driver

[Eason Yang]

Change since version 4:
 - Fix comments
 - Add interrupts and reset-gpios to the DT example
 - Use the FIELD_PREP and FIELD_GET
 - Add use_single_write in regmap_config
 - Use regmap_access_table

Change since version 3:
 - Fix comments
 - Don't put nct720"x" in the name, just call it nct7201
 - Remove differential inputs until conversions are finished
 - Add NCT7201_ prefix in all macros and avoid the tables
 - Correct event threshold values in raw units
 - Add with and without interrupt callback function to have the event
   config part and one that doesn't
 - Remove print an error message if regmap_wirte failed case

Change since version 2:
 - Remvoe read-vin-data-size property, default use read word vin data
 - Use regmap instead of i2c smbus API
 - IIO should be IIO_CHAN_INFO_RAW and _SCALE not _PROCESSED
 - Use dev_xxx_probe in probe function and dev_xxx in other functions
 - Use devm_iio_device_register replace of iio_device_register
 - Use guard(mutex) replace of mutex_lock
 - Use get_unaligned_le16 conversion API

Changes since version 1:
 - Add new property in iio:adc binding document
 - Add new driver for Nuvoton NCT720x driver

Eason Yang (2):
  dt-bindings: iio: adc: add NCT7201 ADCs
  iio: adc: add support for Nuvoton NCT7201

 .../bindings/iio/adc/nuvoton,nct7201.yaml     |  57 ++
 MAINTAINERS                                   |   2 +
 drivers/iio/adc/Kconfig                       |  11 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/nct7201.c                     | 487 ++++++++++++++++++
 5 files changed, 558 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
 create mode 100644 drivers/iio/adc/nct7201.c

-- 
2.34.1

[PATCH v4 1/2] dt-bindings: iio: adc: add NCT7201 ADCs

[Eason Yang]

Add a binding specification for the Nuvoton NCT7201/NCT7202 up to 12-bit
ADCs with I2C interface.

Signed-off-by: Eason Yang <j2anfernee@gmail.com>
---
 .../bindings/iio/adc/nuvoton,nct7201.yaml     | 57 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 58 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
new file mode 100644
index 000000000000..830c37fd9f22
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/nuvoton,nct7201.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton nct7201 and similar ADCs
+
+maintainers:
+  - Eason Yang <j2anfernee@gmail.com>
+
+description: |
+  The NCT7201/NCT7202 is a Nuvoton Hardware Monitor IC, contains up to 12 voltage
+  monitoring channels, with SMBus interface, and up to 4 sets SMBus address
+  selection by ADDR connection. It also provides ALERT# signal for event
+  notification and reset input RSTIN# to recover it from a fault condition.
+
+properties:
+  compatible:
+    enum:
+      - nuvoton,nct7201
+      - nuvoton,nct7202
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  reset-gpios:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@1d {
+            compatible = "nuvoton,nct7202";
+            reg = <0x1d>;
+            interrupt-parent = <&gpio3>;
+            interrupts = <30 IRQ_TYPE_LEVEL_LOW>;
+            reset-gpios = <&gpio3 28 GPIO_ACTIVE_LOW>;
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 3864d473f52f..fdc4aa5c7eff 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2831,6 +2831,7 @@ L:	openbmc@lists.ozlabs.org (moderated for non-subscribers)
 S:	Supported
 F:	Documentation/devicetree/bindings/*/*/*npcm*
 F:	Documentation/devicetree/bindings/*/*npcm*
+F:	Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
 F:	Documentation/devicetree/bindings/rtc/nuvoton,nct3018y.yaml
 F:	arch/arm/boot/dts/nuvoton/nuvoton-npcm*
 F:	arch/arm/mach-npcm/
-- 
2.34.1

[PATCH v4 2/2] iio: adc: add support for Nuvoton NCT7201

[Eason Yang]

Add Nuvoton NCT7201/NCT7202 system voltage monitor 12-bit ADC driver

NCT7201/NCT7202 supports up to 12 analog voltage monitor inputs and up to
4 SMBus addresses by ADDR pin. Meanwhile, ALERT# hardware event pins for
independent alarm signals, and the all threshold values could be set for
system protection without any timing delay. It also supports reset input
RSTIN# to recover system from a fault condition.

Currently, only single-edge mode conversion and threshold events support.

Signed-off-by: Eason Yang <j2anfernee@gmail.com>
---
 MAINTAINERS               |   1 +
 drivers/iio/adc/Kconfig   |  11 +
 drivers/iio/adc/Makefile  |   1 +
 drivers/iio/adc/nct7201.c | 487 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 500 insertions(+)
 create mode 100644 drivers/iio/adc/nct7201.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fdc4aa5c7eff..389cbbdae1a7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2838,6 +2838,7 @@ F:	arch/arm/mach-npcm/
 F:	arch/arm64/boot/dts/nuvoton/
 F:	drivers/*/*/*npcm*
 F:	drivers/*/*npcm*
+F:	drivers/iio/adc/nct7201.c
 F:	drivers/rtc/rtc-nct3018y.c
 F:	include/dt-bindings/clock/nuvoton,npcm7xx-clock.h
 F:	include/dt-bindings/clock/nuvoton,npcm845-clk.h
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 849c90203071..d97eccb1c685 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1048,6 +1048,17 @@ config NAU7802
 	  To compile this driver as a module, choose M here: the
 	  module will be called nau7802.
 
+config NCT7201
+        tristate "Nuvoton NCT7201 and NCT7202 Power Monitor"
+        depends on I2C
+        select REGMAP_I2C
+        help
+          Say yes here to build support for Nuvoton NCT7201 and NCT7202
+          Voltage Monitor.
+
+          This driver can also be built as a module. If so, the module
+          will be called nct7201.
+
 config NPCM_ADC
 	tristate "Nuvoton NPCM ADC driver"
 	depends on ARCH_NPCM || COMPILE_TEST
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index ee19afba62b7..0108472e141c 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -94,6 +94,7 @@ obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
 obj-$(CONFIG_MP2629_ADC) += mp2629_adc.o
 obj-$(CONFIG_MXS_LRADC_ADC) += mxs-lradc-adc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
+obj-$(CONFIG_NCT7201) += nct7201.o
 obj-$(CONFIG_NPCM_ADC) += npcm_adc.o
 obj-$(CONFIG_PAC1921) += pac1921.o
 obj-$(CONFIG_PAC1934) += pac1934.o
diff --git a/drivers/iio/adc/nct7201.c b/drivers/iio/adc/nct7201.c
new file mode 100644
index 000000000000..c5d1540bcc00
--- /dev/null
+++ b/drivers/iio/adc/nct7201.c
@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Nuvoton nct7201 and nct7202 power monitor chips.
+ *
+ * Copyright (c) 2024-2025 Nuvoton Technology corporation.
+ */
+
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+#include <linux/unaligned.h>
+
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+
+#define NCT7201_VIN_MAX				12
+#define NCT7201_IN_SCALING				4995
+#define NCT7201_IN_SCALING_FACTOR			10000
+
+#define NCT7201_REG_INTERRUPT_STATUS_1			0x0C
+#define NCT7201_REG_INTERRUPT_STATUS_2			0x0D
+#define NCT7201_REG_VOLT_LOW_BYTE			0x0F
+#define NCT7201_REG_CONFIGURATION			0x10
+#define  NCT7201_BIT_CONFIGURATION_START		BIT(0)
+#define  NCT7201_BIT_CONFIGURATION_ALERT_MSK		BIT(1)
+#define  NCT7201_BIT_CONFIGURATION_CONV_RATE		BIT(2)
+#define  NCT7201_BIT_CONFIGURATION_RESET		BIT(7)
+
+#define NCT7201_REG_ADVANCED_CONFIGURATION		0x11
+#define  NCT7201_BIT_ADVANCED_CONF_MOD_ALERT		BIT(0)
+#define  NCT7201_BIT_ADVANCED_CONF_MOD_STS		BIT(1)
+#define  NCT7201_BIT_ADVANCED_CONF_FAULT_QUEUE		BIT(2)
+#define  NCT7201_BIT_ADVANCED_CONF_EN_DEEP_SHUTDOWN	BIT(4)
+#define  NCT7201_BIT_ADVANCED_CONF_EN_SMB_TIMEOUT	BIT(5)
+#define  NCT7201_BIT_ADVANCED_CONF_MOD_RSTIN		BIT(7)
+
+#define NCT7201_REG_CHANNEL_INPUT_MODE			0x12
+#define NCT7201_REG_CHANNEL_ENABLE_1			0x13
+#define  NCT7201_REG_CHANNEL_ENABLE_1_MASK		GENMASK(7, 0)
+#define NCT7201_REG_CHANNEL_ENABLE_2			0x14
+#define  NCT7201_REG_CHANNEL_ENABLE_2_MASK		GENMASK(3, 0)
+#define NCT7201_REG_INTERRUPT_MASK_1			0x15
+#define NCT7201_REG_INTERRUPT_MASK_2			0x16
+#define NCT7201_REG_BUSY_STATUS				0x1E
+#define  NCT7201_BIT_BUSY				BIT(0)
+#define  NCT7201_BIT_PWR_UP				BIT(1)
+#define NCT7201_REG_ONE_SHOT				0x1F
+#define NCT7201_REG_SMUS_ADDRESS			0xFC
+#define NCT7201_REG_VIN_MASK				GENMASK(15, 3)
+
+#define NCT7201_REG_VIN(i)				(i)
+#define NCT7201_REG_VIN_HIGH_LIMIT(i)			(0x20 + (i) * 2)
+#define NCT7201_REG_VIN_LOW_LIMIT(i)			(0x21 + (i) * 2)
+
+static const struct regmap_range nct7201_read_reg_range[] = {
+	regmap_reg_range(NCT7201_REG_INTERRUPT_STATUS_1, NCT7201_REG_BUSY_STATUS),
+	regmap_reg_range(NCT7201_REG_SMUS_ADDRESS, NCT7201_REG_SMUS_ADDRESS),
+};
+
+static const struct regmap_access_table nct7201_readable_regs_tbl = {
+	.yes_ranges = nct7201_read_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(nct7201_read_reg_range),
+};
+
+static const struct regmap_range nct7201_write_reg_range[] = {
+	regmap_reg_range(NCT7201_REG_CONFIGURATION, NCT7201_REG_INTERRUPT_MASK_2),
+	regmap_reg_range(NCT7201_REG_ONE_SHOT, NCT7201_REG_ONE_SHOT),
+};
+
+static const struct regmap_access_table nct7201_writeable_regs_tbl = {
+	.yes_ranges = nct7201_write_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(nct7201_write_reg_range),
+};
+
+static const struct regmap_range nct7201_read_vin_reg_range[] = {
+	regmap_reg_range(NCT7201_REG_VIN(0), NCT7201_REG_VIN(NCT7201_VIN_MAX - 1)),
+	regmap_reg_range(NCT7201_REG_VIN_HIGH_LIMIT(0),
+			 NCT7201_REG_VIN_LOW_LIMIT(NCT7201_VIN_MAX - 1)),
+};
+
+static const struct regmap_access_table nct7201_readable_vin_regs_tbl = {
+	.yes_ranges = nct7201_read_vin_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(nct7201_read_vin_reg_range),
+};
+
+static const struct regmap_range nct7201_write_vin_reg_range[] = {
+	regmap_reg_range(NCT7201_REG_VIN_HIGH_LIMIT(0),
+			 NCT7201_REG_VIN_LOW_LIMIT(NCT7201_VIN_MAX - 1)),
+};
+
+static const struct regmap_access_table nct7201_writeable_vin_regs_tbl = {
+	.yes_ranges = nct7201_write_vin_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(nct7201_write_vin_reg_range),
+};
+
+static const struct regmap_config nct7201_regmap8_config = {
+	.name = "vin-data-read-byte",
+	.reg_bits = 8,
+	.val_bits = 8,
+	.use_single_write = true,
+	.max_register = 0xff,
+	.rd_table = &nct7201_readable_regs_tbl,
+	.wr_table = &nct7201_writeable_regs_tbl,
+};
+
+static const struct regmap_config nct7201_regmap16_config = {
+	.name = "vin-data-read-word",
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = 0xff,
+	.rd_table = &nct7201_readable_vin_regs_tbl,
+	.wr_table = &nct7201_writeable_vin_regs_tbl,
+};
+
+struct nct7201_chip_info {
+	struct i2c_client *client;
+	struct mutex access_lock;
+	struct regmap *regmap;
+	struct regmap *regmap16;
+	int num_vin_channels;
+	u16 vin_mask;
+};
+
+struct nct7201_adc_model_data {
+	const char *model_name;
+	const struct iio_chan_spec *channels;
+	const int num_channels;
+	int num_vin_channels;
+};
+
+static const struct iio_event_spec nct7201_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+				 BIT(IIO_EV_INFO_ENABLE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+				 BIT(IIO_EV_INFO_ENABLE),
+	},
+};
+
+#define NCT7201_VOLTAGE_CHANNEL(chan, addr)				\
+	{								\
+		.type = IIO_VOLTAGE,					\
+		.indexed = 1,						\
+		.channel = chan,					\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+		.address = addr,					\
+		.event_spec = nct7201_events,				\
+		.num_event_specs = ARRAY_SIZE(nct7201_events),		\
+	}
+
+static const struct iio_chan_spec nct7201_channels[] = {
+	NCT7201_VOLTAGE_CHANNEL(1, 0),
+	NCT7201_VOLTAGE_CHANNEL(2, 1),
+	NCT7201_VOLTAGE_CHANNEL(3, 2),
+	NCT7201_VOLTAGE_CHANNEL(4, 3),
+	NCT7201_VOLTAGE_CHANNEL(5, 4),
+	NCT7201_VOLTAGE_CHANNEL(6, 5),
+	NCT7201_VOLTAGE_CHANNEL(7, 6),
+	NCT7201_VOLTAGE_CHANNEL(8, 7),
+};
+
+static const struct iio_chan_spec nct7202_channels[] = {
+	NCT7201_VOLTAGE_CHANNEL(1, 0),
+	NCT7201_VOLTAGE_CHANNEL(2, 1),
+	NCT7201_VOLTAGE_CHANNEL(3, 2),
+	NCT7201_VOLTAGE_CHANNEL(4, 3),
+	NCT7201_VOLTAGE_CHANNEL(5, 4),
+	NCT7201_VOLTAGE_CHANNEL(6, 5),
+	NCT7201_VOLTAGE_CHANNEL(7, 6),
+	NCT7201_VOLTAGE_CHANNEL(8, 7),
+	NCT7201_VOLTAGE_CHANNEL(9, 8),
+	NCT7201_VOLTAGE_CHANNEL(10, 9),
+	NCT7201_VOLTAGE_CHANNEL(11, 10),
+	NCT7201_VOLTAGE_CHANNEL(12, 11),
+};
+
+static int nct7201_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	u16 volt;
+	unsigned int value;
+	int err;
+	struct nct7201_chip_info *chip = iio_priv(indio_dev);
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	guard(mutex)(&chip->access_lock);
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		err = regmap_read(chip->regmap16, NCT7201_REG_VIN(chan->address), &value);
+		if (err < 0)
+			return err;
+		volt = value;
+		*val = FIELD_GET(NCT7201_REG_VIN_MASK, volt);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* From the datasheet, we have to multiply by 0.0004995 */
+		*val = 0;
+		*val2 = 499500;
+		return IIO_VAL_INT_PLUS_NANO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int nct7201_read_event_value(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir,
+				    enum iio_event_info info,
+				    int *val, int *val2)
+{
+	struct nct7201_chip_info *chip = iio_priv(indio_dev);
+	u16 volt;
+	unsigned int value;
+	int err;
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	if (info != IIO_EV_INFO_VALUE)
+		return -EINVAL;
+
+	if (dir == IIO_EV_DIR_FALLING) {
+		err = regmap_read(chip->regmap16, NCT7201_REG_VIN_LOW_LIMIT(chan->address),
+				  &value);
+		if (err < 0)
+			return err;
+		volt = value;
+	} else {
+		err = regmap_read(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
+				  &value);
+		if (err < 0)
+			return err;
+		volt = value;
+	}
+
+	*val = FIELD_GET(NCT7201_REG_VIN_MASK, volt);
+
+	return IIO_VAL_INT;
+}
+
+static int nct7201_write_event_value(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir,
+				     enum iio_event_info info,
+				     int val, int val2)
+{
+	struct nct7201_chip_info *chip = iio_priv(indio_dev);
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	if (info != IIO_EV_INFO_VALUE)
+		return -EOPNOTSUPP;
+
+	if (dir == IIO_EV_DIR_FALLING)
+		regmap_write(chip->regmap16, NCT7201_REG_VIN_LOW_LIMIT(chan->address),
+			     FIELD_PREP(NCT7201_REG_VIN_MASK, val));
+	else
+		regmap_write(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
+			     FIELD_PREP(NCT7201_REG_VIN_MASK, val));
+
+	return 0;
+}
+
+static int nct7201_read_event_config(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir)
+{
+	struct nct7201_chip_info *chip = iio_priv(indio_dev);
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	return !!(chip->vin_mask & BIT(chan->address));
+}
+
+static int nct7201_write_event_config(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan,
+				      enum iio_event_type type,
+				      enum iio_event_direction dir,
+				      bool state)
+{
+	struct nct7201_chip_info *chip = iio_priv(indio_dev);
+	unsigned int mask;
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	mask = BIT(chan->address);
+
+	if (!state && (chip->vin_mask & mask))
+		chip->vin_mask &= ~mask;
+	else if (state && !(chip->vin_mask & mask))
+		chip->vin_mask |= mask;
+
+	if (chip->num_vin_channels <= 8)
+		regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1, chip->vin_mask);
+	else
+		regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
+				  &chip->vin_mask, sizeof(chip->vin_mask));
+
+	return 0;
+}
+
+static const struct iio_info nct7201_info = {
+	.read_raw = nct7201_read_raw,
+	.read_event_config = nct7201_read_event_config,
+	.write_event_config = nct7201_write_event_config,
+	.read_event_value = nct7201_read_event_value,
+	.write_event_value = nct7201_write_event_value,
+};
+
+static const struct iio_info nct7201_info_no_irq = {
+	.read_raw = nct7201_read_raw,
+};
+
+static const struct nct7201_adc_model_data nct7201_model_data = {
+	.model_name = "nct7201",
+	.channels = nct7201_channels,
+	.num_channels = ARRAY_SIZE(nct7201_channels),
+	.num_vin_channels = 8,
+};
+
+static const struct nct7201_adc_model_data nct7202_model_data = {
+	.model_name = "nct7202",
+	.channels = nct7202_channels,
+	.num_channels = ARRAY_SIZE(nct7202_channels),
+	.num_vin_channels = 12,
+};
+
+static int nct7201_init_chip(struct nct7201_chip_info *chip)
+{
+	u8 data[2];
+	unsigned int value;
+	int err;
+
+	regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
+		     NCT7201_BIT_CONFIGURATION_RESET);
+
+	/*
+	 * After about 25 msecs, the device should be ready and then
+	 * the Power Up bit will be set to 1. If not, wait for it.
+	 */
+	mdelay(25);
+	err = regmap_read(chip->regmap, NCT7201_REG_BUSY_STATUS, &value);
+	if (err < 0)
+		return err;
+	if (!(value & NCT7201_BIT_PWR_UP))
+		return dev_err_probe(&chip->client->dev, -EIO,
+				     "Failed to power up after reset\n");
+
+	/* Enable Channel */
+	if (chip->num_vin_channels <= 8) {
+		data[0] = NCT7201_REG_CHANNEL_ENABLE_1_MASK;
+		err = regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1, data[0]);
+		if (err < 0)
+			return dev_err_probe(&chip->client->dev, -EIO,
+					     "Failed to write NCT7201_REG_CHANNEL_ENABLE_1\n");
+	} else {
+		data[0] = NCT7201_REG_CHANNEL_ENABLE_1_MASK;
+		data[1] = NCT7201_REG_CHANNEL_ENABLE_2_MASK;
+		err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
+					data, ARRAY_SIZE(data));
+		if (err < 0)
+			return dev_err_probe(&chip->client->dev, -EIO,
+					    "Failed to write NCT7201_REG_CHANNEL_ENABLE_1 and NCT7201_REG_CHANNEL_ENABLE_2\n");
+	}
+
+	value = get_unaligned_le16(data);
+	chip->vin_mask = value;
+
+	/* Start monitoring if needed */
+	err = regmap_read(chip->regmap, NCT7201_REG_CONFIGURATION, &value);
+	if (err < 0)
+		return dev_err_probe(&chip->client->dev, -EIO,
+				     "Failed to read NCT7201_REG_CONFIGURATION\n");
+
+	regmap_set_bits(chip->regmap, NCT7201_REG_CONFIGURATION, NCT7201_BIT_CONFIGURATION_START);
+
+	return 0;
+}
+
+static int nct7201_probe(struct i2c_client *client)
+{
+	const struct nct7201_adc_model_data *model_data;
+	struct nct7201_chip_info *chip;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	model_data = i2c_get_match_data(client);
+	if (!model_data)
+		return -EINVAL;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
+	if (!indio_dev)
+		return -ENOMEM;
+	chip = iio_priv(indio_dev);
+
+	chip->regmap = devm_regmap_init_i2c(client, &nct7201_regmap8_config);
+	if (IS_ERR(chip->regmap))
+		return dev_err_probe(&client->dev, PTR_ERR(chip->regmap),
+			"Failed to init regmap\n");
+
+	chip->regmap16 = devm_regmap_init_i2c(client, &nct7201_regmap16_config);
+	if (IS_ERR(chip->regmap16))
+		return dev_err_probe(&client->dev, PTR_ERR(chip->regmap16),
+			"Failed to init regmap16\n");
+
+	chip->num_vin_channels = model_data->num_vin_channels;
+
+	ret = devm_mutex_init(&client->dev, &chip->access_lock);
+	if (ret)
+		return ret;
+
+	chip->client = client;
+
+	ret = nct7201_init_chip(chip);
+	if (ret < 0)
+		return ret;
+
+	indio_dev->name = model_data->model_name;
+	indio_dev->channels = model_data->channels;
+	indio_dev->num_channels = model_data->num_channels;
+	if (client->irq)
+		indio_dev->info = &nct7201_info;
+	else
+		indio_dev->info = &nct7201_info_no_irq;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id nct7201_id[] = {
+	{ .name = "nct7201", .driver_data = (kernel_ulong_t)&nct7201_model_data },
+	{ .name = "nct7202", .driver_data = (kernel_ulong_t)&nct7202_model_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, nct7201_id);
+
+static const struct of_device_id nct7201_of_match[] = {
+	{
+		.compatible = "nuvoton,nct7201",
+		.data = &nct7201_model_data,
+	},
+	{
+		.compatible = "nuvoton,nct7202",
+		.data = &nct7202_model_data,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, nct7201_of_match);
+
+static struct i2c_driver nct7201_driver = {
+	.driver = {
+		.name	= "nct7201",
+		.of_match_table = nct7201_of_match,
+	},
+	.probe = nct7201_probe,
+	.id_table = nct7201_id,
+};
+module_i2c_driver(nct7201_driver);
+
+MODULE_AUTHOR("Eason Yang <j2anfernee@gmail.com>");
+MODULE_DESCRIPTION("Nuvoton NCT7201 voltage monitor driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1

Re: [PATCH v4 1/2] dt-bindings: iio: adc: add NCT7201 ADCs

[David Lechner]

On 2/21/25 3:09 AM, Eason Yang wrote:
> Add a binding specification for the Nuvoton NCT7201/NCT7202 up to 12-bit
> ADCs with I2C interface.
> 
> Signed-off-by: Eason Yang <j2anfernee@gmail.com>
> ---
>  .../bindings/iio/adc/nuvoton,nct7201.yaml     | 57 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 58 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> new file mode 100644
> index 000000000000..830c37fd9f22
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> @@ -0,0 +1,57 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/nuvoton,nct7201.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Nuvoton nct7201 and similar ADCs
> +
> +maintainers:
> +  - Eason Yang <j2anfernee@gmail.com>
> +
> +description: |
> +  The NCT7201/NCT7202 is a Nuvoton Hardware Monitor IC, contains up to 12 voltage
> +  monitoring channels, with SMBus interface, and up to 4 sets SMBus address
> +  selection by ADDR connection. It also provides ALERT# signal for event
> +  notification and reset input RSTIN# to recover it from a fault condition.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - nuvoton,nct7201
> +      - nuvoton,nct7202
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  reset-gpios:
> +    maxItems: 1
> +

Maybe this was brought up before, but no power supply?

> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        adc@1d {
> +            compatible = "nuvoton,nct7202";
> +            reg = <0x1d>;
> +            interrupt-parent = <&gpio3>;
> +            interrupts = <30 IRQ_TYPE_LEVEL_LOW>;
> +            reset-gpios = <&gpio3 28 GPIO_ACTIVE_LOW>;
> +        };
> +    };
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3864d473f52f..fdc4aa5c7eff 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2831,6 +2831,7 @@ L:	openbmc@lists.ozlabs.org (moderated for non-subscribers)
>  S:	Supported
>  F:	Documentation/devicetree/bindings/*/*/*npcm*
>  F:	Documentation/devicetree/bindings/*/*npcm*
> +F:	Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml

This (ARM/NUVOTON NPCM ARCHITECTURE) doesn't look like the right place for
adding a stand-alone chip. You will need to start a new section like:

NUVOTON NCT7201 IIO DRIVER

>  F:	Documentation/devicetree/bindings/rtc/nuvoton,nct3018y.yaml
>  F:	arch/arm/boot/dts/nuvoton/nuvoton-npcm*
>  F:	arch/arm/mach-npcm/

Re: [PATCH v4 2/2] iio: adc: add support for Nuvoton NCT7201

[David Lechner]

On 2/21/25 3:09 AM, Eason Yang wrote:
> Add Nuvoton NCT7201/NCT7202 system voltage monitor 12-bit ADC driver
> 
> NCT7201/NCT7202 supports up to 12 analog voltage monitor inputs and up to
> 4 SMBus addresses by ADDR pin. Meanwhile, ALERT# hardware event pins for
> independent alarm signals, and the all threshold values could be set for
> system protection without any timing delay. It also supports reset input
> RSTIN# to recover system from a fault condition.
> 
> Currently, only single-edge mode conversion and threshold events support.
> 
> Signed-off-by: Eason Yang <j2anfernee@gmail.com>
> ---
>  MAINTAINERS               |   1 +
>  drivers/iio/adc/Kconfig   |  11 +
>  drivers/iio/adc/Makefile  |   1 +
>  drivers/iio/adc/nct7201.c | 487 ++++++++++++++++++++++++++++++++++++++
>  4 files changed, 500 insertions(+)
>  create mode 100644 drivers/iio/adc/nct7201.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fdc4aa5c7eff..389cbbdae1a7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2838,6 +2838,7 @@ F:	arch/arm/mach-npcm/
>  F:	arch/arm64/boot/dts/nuvoton/
>  F:	drivers/*/*/*npcm*
>  F:	drivers/*/*npcm*
> +F:	drivers/iio/adc/nct7201.c

Same comment as DT bindings, this is ARM/NUVOTON NPCM ARCHITECTURE.
We need a new section for this chip since it is stand-alone.

>  F:	drivers/rtc/rtc-nct3018y.c
>  F:	include/dt-bindings/clock/nuvoton,npcm7xx-clock.h
>  F:	include/dt-bindings/clock/nuvoton,npcm845-clk.h

...

> diff --git a/drivers/iio/adc/nct7201.c b/drivers/iio/adc/nct7201.c
> new file mode 100644
> index 000000000000..c5d1540bcc00
> --- /dev/null
> +++ b/drivers/iio/adc/nct7201.c
> @@ -0,0 +1,487 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Driver for Nuvoton nct7201 and nct7202 power monitor chips.
> + *
> + * Copyright (c) 2024-2025 Nuvoton Technology corporation.
> + */
> +
> +#include <linux/array_size.h>
> +#include <linux/bits.h>
> +#include <linux/cleanup.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>

Are we really using something from the init header?

> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/regmap.h>
> +#include <linux/types.h>
> +#include <linux/unaligned.h>
> +
> +#include <linux/iio/events.h>
> +#include <linux/iio/iio.h>
> +

...

> +static int nct7201_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int *val, int *val2, long mask)
> +{
> +	u16 volt;
> +	unsigned int value;
> +	int err;
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	guard(mutex)(&chip->access_lock);

The regmap should already have an intneral lock, so this mutex seems
reduandnt in it's current usage.

> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		err = regmap_read(chip->regmap16, NCT7201_REG_VIN(chan->address), &value);
> +		if (err < 0)
> +			return err;
> +		volt = value;
> +		*val = FIELD_GET(NCT7201_REG_VIN_MASK, volt);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		/* From the datasheet, we have to multiply by 0.0004995 */
> +		*val = 0;
> +		*val2 = 499500;
> +		return IIO_VAL_INT_PLUS_NANO;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int nct7201_read_event_value(struct iio_dev *indio_dev,
> +				    const struct iio_chan_spec *chan,
> +				    enum iio_event_type type,
> +				    enum iio_event_direction dir,
> +				    enum iio_event_info info,
> +				    int *val, int *val2)
> +{
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +	u16 volt;
> +	unsigned int value;
> +	int err;
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	if (info != IIO_EV_INFO_VALUE)
> +		return -EINVAL;
> +
> +	if (dir == IIO_EV_DIR_FALLING) {
> +		err = regmap_read(chip->regmap16, NCT7201_REG_VIN_LOW_LIMIT(chan->address),
> +				  &value);
> +		if (err < 0)
> +			return err;
> +		volt = value;

Assigning to volt seems reduant. We can just pass value to
FIELD_GET() below.

> +	} else {
> +		err = regmap_read(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> +				  &value);
> +		if (err < 0)
> +			return err;
> +		volt = value;
> +	}
> +
> +	*val = FIELD_GET(NCT7201_REG_VIN_MASK, volt);
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static int nct7201_write_event_value(struct iio_dev *indio_dev,
> +				     const struct iio_chan_spec *chan,
> +				     enum iio_event_type type,
> +				     enum iio_event_direction dir,
> +				     enum iio_event_info info,
> +				     int val, int val2)
> +{
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	if (info != IIO_EV_INFO_VALUE)
> +		return -EOPNOTSUPP;
> +
> +	if (dir == IIO_EV_DIR_FALLING)
> +		regmap_write(chip->regmap16, NCT7201_REG_VIN_LOW_LIMIT(chan->address),
> +			     FIELD_PREP(NCT7201_REG_VIN_MASK, val));

No error checking? Could just return here directly.

> +	else
> +		regmap_write(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> +			     FIELD_PREP(NCT7201_REG_VIN_MASK, val));
> +
> +	return 0;
> +}
> +

...

> +static int nct7201_write_event_config(struct iio_dev *indio_dev,
> +				      const struct iio_chan_spec *chan,
> +				      enum iio_event_type type,
> +				      enum iio_event_direction dir,
> +				      bool state)
> +{
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +	unsigned int mask;
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	mask = BIT(chan->address);
> +
> +	if (!state && (chip->vin_mask & mask))
> +		chip->vin_mask &= ~mask;
> +	else if (state && !(chip->vin_mask & mask))
> +		chip->vin_mask |= mask;

This would be easier to read as:

	if (state)
		chip->vin_mask |= mask;
	else
		chip->vin_mask &= ~mask;

> +
> +	if (chip->num_vin_channels <= 8)
> +		regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1, chip->vin_mask);

No error checking?

> +	else
> +		regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
> +				  &chip->vin_mask, sizeof(chip->vin_mask));
> +
> +	return 0;
> +}
> +

...

> +static int nct7201_init_chip(struct nct7201_chip_info *chip)
> +{
> +	u8 data[2];
> +	unsigned int value;
> +	int err;
> +
> +	regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
> +		     NCT7201_BIT_CONFIGURATION_RESET);

Check error return?

> +
> +	/*
> +	 * After about 25 msecs, the device should be ready and then
> +	 * the Power Up bit will be set to 1. If not, wait for it.
> +	 */
> +	mdelay(25);
> +	err = regmap_read(chip->regmap, NCT7201_REG_BUSY_STATUS, &value);
> +	if (err < 0)
> +		return err;
> +	if (!(value & NCT7201_BIT_PWR_UP))
> +		return dev_err_probe(&chip->client->dev, -EIO,
> +				     "Failed to power up after reset\n");
> +
> +	/* Enable Channel */
> +	if (chip->num_vin_channels <= 8) {
> +		data[0] = NCT7201_REG_CHANNEL_ENABLE_1_MASK;
> +		err = regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1, data[0]);
> +		if (err < 0)
> +			return dev_err_probe(&chip->client->dev, -EIO,
> +					     "Failed to write NCT7201_REG_CHANNEL_ENABLE_1\n");
> +	} else {
> +		data[0] = NCT7201_REG_CHANNEL_ENABLE_1_MASK;
> +		data[1] = NCT7201_REG_CHANNEL_ENABLE_2_MASK;
> +		err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
> +					data, ARRAY_SIZE(data));
> +		if (err < 0)
> +			return dev_err_probe(&chip->client->dev, -EIO,
> +					    "Failed to write NCT7201_REG_CHANNEL_ENABLE_1 and NCT7201_REG_CHANNEL_ENABLE_2\n");
> +	}
> +
> +	value = get_unaligned_le16(data);

Does it matter that data[1] may be uninitialized and contain random value here?

> +	chip->vin_mask = value;

Don't really need the intermediate value assignment here.

> +
> +	/* Start monitoring if needed */
> +	err = regmap_read(chip->regmap, NCT7201_REG_CONFIGURATION, &value);
> +	if (err < 0)
> +		return dev_err_probe(&chip->client->dev, -EIO,
> +				     "Failed to read NCT7201_REG_CONFIGURATION\n");
> +
> +	regmap_set_bits(chip->regmap, NCT7201_REG_CONFIGURATION, NCT7201_BIT_CONFIGURATION_START);
> +
> +	return 0;
> +}
> +

Re: [PATCH v4 1/2] dt-bindings: iio: adc: add NCT7201 ADCs

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 3014 bytes --]

On Fri, Feb 21, 2025 at 05:09:17PM +0800, Eason Yang wrote:
> Add a binding specification for the Nuvoton NCT7201/NCT7202 up to 12-bit
> ADCs with I2C interface.
> 
> Signed-off-by: Eason Yang <j2anfernee@gmail.com>
> ---
>  .../bindings/iio/adc/nuvoton,nct7201.yaml     | 57 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 58 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> new file mode 100644
> index 000000000000..830c37fd9f22
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> @@ -0,0 +1,57 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/nuvoton,nct7201.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Nuvoton nct7201 and similar ADCs
> +
> +maintainers:
> +  - Eason Yang <j2anfernee@gmail.com>
> +
> +description: |
> +  The NCT7201/NCT7202 is a Nuvoton Hardware Monitor IC, contains up to 12 voltage
> +  monitoring channels, with SMBus interface, and up to 4 sets SMBus address
> +  selection by ADDR connection. It also provides ALERT# signal for event
> +  notification and reset input RSTIN# to recover it from a fault condition.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - nuvoton,nct7201
> +      - nuvoton,nct7202

When you respin, please add a note about what differs between these
devices that requires different handling in the driver.

Cheers,
Conor.

> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  reset-gpios:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        adc@1d {
> +            compatible = "nuvoton,nct7202";
> +            reg = <0x1d>;
> +            interrupt-parent = <&gpio3>;
> +            interrupts = <30 IRQ_TYPE_LEVEL_LOW>;
> +            reset-gpios = <&gpio3 28 GPIO_ACTIVE_LOW>;
> +        };
> +    };
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3864d473f52f..fdc4aa5c7eff 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2831,6 +2831,7 @@ L:	openbmc@lists.ozlabs.org (moderated for non-subscribers)
>  S:	Supported
>  F:	Documentation/devicetree/bindings/*/*/*npcm*
>  F:	Documentation/devicetree/bindings/*/*npcm*
> +F:	Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
>  F:	Documentation/devicetree/bindings/rtc/nuvoton,nct3018y.yaml
>  F:	arch/arm/boot/dts/nuvoton/nuvoton-npcm*
>  F:	arch/arm/mach-npcm/
> -- 
> 2.34.1
> 

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Re: [PATCH v4 0/2] iio: adc: add Nuvoton NCT7201 ADC driver

[Jonathan Cameron]

On Fri, 21 Feb 2025 17:09:16 +0800
Eason Yang <j2anfernee@gmail.com> wrote:

Hi Eason,

Not sure if I asked this before, but this is a device that seems
to be typically used for hardware monitoring and there are a number
of similar sounding device in drivers/hwmon/  

That raises a couple of questions:
1) Is it compatible with any of those existing drivers?
2) Why IIO rather than HWMON?

There isn't normally a problem with having a hardware monitoring
related device supported by IIO, it is just good to know if your
usecase makes that a good idea.  We have the iio-hwmon bridge
driver to solve the problem of a device than can be used either
as a generic ADC or as a hwmon type monitoring device (which tends
to have more alarms etc)

Jonathan


> Change since version 4:
>  - Fix comments
>  - Add interrupts and reset-gpios to the DT example
>  - Use the FIELD_PREP and FIELD_GET
>  - Add use_single_write in regmap_config
>  - Use regmap_access_table
> 
> Change since version 3:
>  - Fix comments
>  - Don't put nct720"x" in the name, just call it nct7201
>  - Remove differential inputs until conversions are finished
>  - Add NCT7201_ prefix in all macros and avoid the tables
>  - Correct event threshold values in raw units
>  - Add with and without interrupt callback function to have the event
>    config part and one that doesn't
>  - Remove print an error message if regmap_wirte failed case
> 
> Change since version 2:
>  - Remvoe read-vin-data-size property, default use read word vin data
>  - Use regmap instead of i2c smbus API
>  - IIO should be IIO_CHAN_INFO_RAW and _SCALE not _PROCESSED
>  - Use dev_xxx_probe in probe function and dev_xxx in other functions
>  - Use devm_iio_device_register replace of iio_device_register
>  - Use guard(mutex) replace of mutex_lock
>  - Use get_unaligned_le16 conversion API
> 
> Changes since version 1:
>  - Add new property in iio:adc binding document
>  - Add new driver for Nuvoton NCT720x driver
> 
> Eason Yang (2):
>   dt-bindings: iio: adc: add NCT7201 ADCs
>   iio: adc: add support for Nuvoton NCT7201
> 
>  .../bindings/iio/adc/nuvoton,nct7201.yaml     |  57 ++
>  MAINTAINERS                                   |   2 +
>  drivers/iio/adc/Kconfig                       |  11 +
>  drivers/iio/adc/Makefile                      |   1 +
>  drivers/iio/adc/nct7201.c                     | 487 ++++++++++++++++++
>  5 files changed, 558 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
>  create mode 100644 drivers/iio/adc/nct7201.c
> 

Re: [PATCH v4 2/2] iio: adc: add support for Nuvoton NCT7201

[Jonathan Cameron]

On Fri, 21 Feb 2025 17:09:18 +0800
Eason Yang <j2anfernee@gmail.com> wrote:

> Add Nuvoton NCT7201/NCT7202 system voltage monitor 12-bit ADC driver
> 
> NCT7201/NCT7202 supports up to 12 analog voltage monitor inputs and up to
> 4 SMBus addresses by ADDR pin. Meanwhile, ALERT# hardware event pins for
> independent alarm signals, and the all threshold values could be set for
> system protection without any timing delay. It also supports reset input
> RSTIN# to recover system from a fault condition.
> 
> Currently, only single-edge mode conversion and threshold events support.
> 
> Signed-off-by: Eason Yang <j2anfernee@gmail.com>
Hi Eason

A few comments from me. May well overlap in some places with other feedback.

Jonathan

> diff --git a/drivers/iio/adc/nct7201.c b/drivers/iio/adc/nct7201.c
> new file mode 100644
> index 000000000000..c5d1540bcc00
> --- /dev/null
> +++ b/drivers/iio/adc/nct7201.c
> @@ -0,0 +1,487 @@

> +
> +#define NCT7201_VOLTAGE_CHANNEL(chan, addr)				\
> +	{								\
> +		.type = IIO_VOLTAGE,					\
> +		.indexed = 1,						\
> +		.channel = chan,					\
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> +		.address = addr,					\
> +		.event_spec = nct7201_events,				\
> +		.num_event_specs = ARRAY_SIZE(nct7201_events),		\
> +	}
> +
> +static const struct iio_chan_spec nct7201_channels[] = {
> +	NCT7201_VOLTAGE_CHANNEL(1, 0),
> +	NCT7201_VOLTAGE_CHANNEL(2, 1),
> +	NCT7201_VOLTAGE_CHANNEL(3, 2),
> +	NCT7201_VOLTAGE_CHANNEL(4, 3),
> +	NCT7201_VOLTAGE_CHANNEL(5, 4),
> +	NCT7201_VOLTAGE_CHANNEL(6, 5),
> +	NCT7201_VOLTAGE_CHANNEL(7, 6),
> +	NCT7201_VOLTAGE_CHANNEL(8, 7),
> +};
> +
> +static const struct iio_chan_spec nct7202_channels[] = {
> +	NCT7201_VOLTAGE_CHANNEL(1, 0),
> +	NCT7201_VOLTAGE_CHANNEL(2, 1),
> +	NCT7201_VOLTAGE_CHANNEL(3, 2),
> +	NCT7201_VOLTAGE_CHANNEL(4, 3),
> +	NCT7201_VOLTAGE_CHANNEL(5, 4),
> +	NCT7201_VOLTAGE_CHANNEL(6, 5),
> +	NCT7201_VOLTAGE_CHANNEL(7, 6),
> +	NCT7201_VOLTAGE_CHANNEL(8, 7),
> +	NCT7201_VOLTAGE_CHANNEL(9, 8),
> +	NCT7201_VOLTAGE_CHANNEL(10, 9),
> +	NCT7201_VOLTAGE_CHANNEL(11, 10),
> +	NCT7201_VOLTAGE_CHANNEL(12, 11),
We normally number channels from 0 which would simplify this but I don't really
mind if you want to keep the offset of 1.  Maybe just have one macro
parameter though and do the +1 in the macro.
> +};

> +static int nct7201_read_event_value(struct iio_dev *indio_dev,
> +				    const struct iio_chan_spec *chan,
> +				    enum iio_event_type type,
> +				    enum iio_event_direction dir,
> +				    enum iio_event_info info,
> +				    int *val, int *val2)
> +{
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +	u16 volt;
> +	unsigned int value;
> +	int err;
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	if (info != IIO_EV_INFO_VALUE)
> +		return -EINVAL;
> +
> +	if (dir == IIO_EV_DIR_FALLING) {
> +		err = regmap_read(chip->regmap16, NCT7201_REG_VIN_LOW_LIMIT(chan->address),
> +				  &value);
> +		if (err < 0)
> +			return err;
> +		volt = value;
> +	} else {
> +		err = regmap_read(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> +				  &value);
> +		if (err < 0)
> +			return err;
> +		volt = value;
No real point in assigning to volt here, 
> +	}
> +
> +	*val = FIELD_GET(NCT7201_REG_VIN_MASK, volt);
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static int nct7201_write_event_value(struct iio_dev *indio_dev,
> +				     const struct iio_chan_spec *chan,
> +				     enum iio_event_type type,
> +				     enum iio_event_direction dir,
> +				     enum iio_event_info info,
> +				     int val, int val2)
> +{
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	if (info != IIO_EV_INFO_VALUE)
> +		return -EOPNOTSUPP;
> +
> +	if (dir == IIO_EV_DIR_FALLING)
> +		regmap_write(chip->regmap16, NCT7201_REG_VIN_LOW_LIMIT(chan->address),
> +			     FIELD_PREP(NCT7201_REG_VIN_MASK, val));
> +	else
> +		regmap_write(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> +			     FIELD_PREP(NCT7201_REG_VIN_MASK, val));
Check for error returns.
> +
> +	return 0;
> +}
> +
> +static int nct7201_read_event_config(struct iio_dev *indio_dev,
> +				     const struct iio_chan_spec *chan,
> +				     enum iio_event_type type,
> +				     enum iio_event_direction dir)
> +{
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	return !!(chip->vin_mask & BIT(chan->address));
> +}
> +
> +static int nct7201_write_event_config(struct iio_dev *indio_dev,
> +				      const struct iio_chan_spec *chan,
> +				      enum iio_event_type type,
> +				      enum iio_event_direction dir,
> +				      bool state)
> +{
> +	struct nct7201_chip_info *chip = iio_priv(indio_dev);
> +	unsigned int mask;
> +
> +	if (chan->type != IIO_VOLTAGE)
> +		return -EOPNOTSUPP;
> +
> +	mask = BIT(chan->address);
> +
> +	if (!state && (chip->vin_mask & mask))
> +		chip->vin_mask &= ~mask;
> +	else if (state && !(chip->vin_mask & mask))
> +		chip->vin_mask |= mask;
> +
> +	if (chip->num_vin_channels <= 8)
> +		regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1, chip->vin_mask);
> +	else
> +		regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
> +				  &chip->vin_mask, sizeof(chip->vin_mask));

Check errors on these writes.

> +
> +	return 0;
> +}

> +static int nct7201_init_chip(struct nct7201_chip_info *chip)
> +{
> +	u8 data[2];
> +	unsigned int value;
> +	int err;
> +
> +	regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
> +		     NCT7201_BIT_CONFIGURATION_RESET);

Check for errors on all accesses to the device.  It can get
fiddly in paths where you are already handling an error but
that's not the case here.

> +
> +	/*
> +	 * After about 25 msecs, the device should be ready and then
> +	 * the Power Up bit will be set to 1. If not, wait for it.

Wrap to 80 chars.

> +	 */
> +	mdelay(25);
> +	err = regmap_read(chip->regmap, NCT7201_REG_BUSY_STATUS, &value);
> +	if (err < 0)
> +		return err;
> +	if (!(value & NCT7201_BIT_PWR_UP))
> +		return dev_err_probe(&chip->client->dev, -EIO,
> +				     "Failed to power up after reset\n");
> +
> +	/* Enable Channel */
> +	if (chip->num_vin_channels <= 8) {
> +		data[0] = NCT7201_REG_CHANNEL_ENABLE_1_MASK;
> +		err = regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1, data[0]);
> +		if (err < 0)
> +			return dev_err_probe(&chip->client->dev, -EIO,
> +					     "Failed to write NCT7201_REG_CHANNEL_ENABLE_1\n");
> +	} else {
> +		data[0] = NCT7201_REG_CHANNEL_ENABLE_1_MASK;
> +		data[1] = NCT7201_REG_CHANNEL_ENABLE_2_MASK;
> +		err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
> +					data, ARRAY_SIZE(data));
> +		if (err < 0)
> +			return dev_err_probe(&chip->client->dev, -EIO,
> +					    "Failed to write NCT7201_REG_CHANNEL_ENABLE_1 and NCT7201_REG_CHANNEL_ENABLE_2\n");
> +	}
> +
> +	value = get_unaligned_le16(data);
> +	chip->vin_mask = value;

Local variable doesn't seem to add any benefits so just assign vin_mask directly.

> +
> +	/* Start monitoring if needed */
> +	err = regmap_read(chip->regmap, NCT7201_REG_CONFIGURATION, &value);
> +	if (err < 0)
> +		return dev_err_probe(&chip->client->dev, -EIO,
> +				     "Failed to read NCT7201_REG_CONFIGURATION\n");
> +
> +	regmap_set_bits(chip->regmap, NCT7201_REG_CONFIGURATION, NCT7201_BIT_CONFIGURATION_START);
> +
> +	return 0;
> +}
> +
> +static int nct7201_probe(struct i2c_client *client)
> +{
> +	const struct nct7201_adc_model_data *model_data;
> +	struct nct7201_chip_info *chip;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	model_data = i2c_get_match_data(client);
> +	if (!model_data)
> +		return -EINVAL;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +	chip = iio_priv(indio_dev);
> +
> +	chip->regmap = devm_regmap_init_i2c(client, &nct7201_regmap8_config);
> +	if (IS_ERR(chip->regmap))
> +		return dev_err_probe(&client->dev, PTR_ERR(chip->regmap),
> +			"Failed to init regmap\n");

Where it doesn't lead to really long lines, align all parameters to just
after the opening bracket.


> +
> +	chip->regmap16 = devm_regmap_init_i2c(client, &nct7201_regmap16_config);
> +	if (IS_ERR(chip->regmap16))
> +		return dev_err_probe(&client->dev, PTR_ERR(chip->regmap16),
> +			"Failed to init regmap16\n");
> +
> +	chip->num_vin_channels = model_data->num_vin_channels;
> +
> +	ret = devm_mutex_init(&client->dev, &chip->access_lock);
> +	if (ret)
> +		return ret;
> +
> +	chip->client = client;
> +
> +	ret = nct7201_init_chip(chip);
> +	if (ret < 0)
> +		return ret;
> +
> +	indio_dev->name = model_data->model_name;
> +	indio_dev->channels = model_data->channels;
> +	indio_dev->num_channels = model_data->num_channels;
> +	if (client->irq)
> +		indio_dev->info = &nct7201_info;
> +	else
> +		indio_dev->info = &nct7201_info_no_irq;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}

Re: [PATCH v4 2/2] iio: adc: add support for Nuvoton NCT7201

[Paul Menzel]

Dear Eason,


Thank you for your patch.

Am 21.02.25 um 10:09 schrieb Eason Yang:
> Add Nuvoton NCT7201/NCT7202 system voltage monitor 12-bit ADC driver
> 
> NCT7201/NCT7202 supports up to 12 analog voltage monitor inputs and up to
> 4 SMBus addresses by ADDR pin. Meanwhile, ALERT# hardware event pins for
> independent alarm signals, and the all threshold values could be set for

… and all the threshold values …

> system protection without any timing delay. It also supports reset input
> RSTIN# to recover system from a fault condition.
> 
> Currently, only single-edge mode conversion and threshold events support.

… are supported.

It’d be great if you added a datasheet name and revision, and, if 
publicly available, a URL.

> Signed-off-by: Eason Yang <j2anfernee@gmail.com>
> ---
>   MAINTAINERS               |   1 +
>   drivers/iio/adc/Kconfig   |  11 +
>   drivers/iio/adc/Makefile  |   1 +
>   drivers/iio/adc/nct7201.c | 487 ++++++++++++++++++++++++++++++++++++++
>   4 files changed, 500 insertions(+)
>   create mode 100644 drivers/iio/adc/nct7201.c

[…]


Kind regards,

Paul

Re: [PATCH v4 1/2] dt-bindings: iio: adc: add NCT7201 ADCs

[Yu-Hsian Yang]

Dear David Lechner,

Thanks again for the review, I'll do the changes here and send next patch.

David Lechner <dlechner@baylibre.com> 於 2025年2月21日 週五 下午11:56寫道：
>
> On 2/21/25 3:09 AM, Eason Yang wrote:
> > Add a binding specification for the Nuvoton NCT7201/NCT7202 up to 12-bit
> > ADCs with I2C interface.
> >
> > Signed-off-by: Eason Yang <j2anfernee@gmail.com>
> > ---
> >  .../bindings/iio/adc/nuvoton,nct7201.yaml     | 57 +++++++++++++++++++
> >  MAINTAINERS                                   |  1 +
> >  2 files changed, 58 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> > new file mode 100644
> > index 000000000000..830c37fd9f22
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> > @@ -0,0 +1,57 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/nuvoton,nct7201.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Nuvoton nct7201 and similar ADCs
> > +
> > +maintainers:
> > +  - Eason Yang <j2anfernee@gmail.com>
> > +
> > +description: |
> > +  The NCT7201/NCT7202 is a Nuvoton Hardware Monitor IC, contains up to 12 voltage
> > +  monitoring channels, with SMBus interface, and up to 4 sets SMBus address
> > +  selection by ADDR connection. It also provides ALERT# signal for event
> > +  notification and reset input RSTIN# to recover it from a fault condition.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - nuvoton,nct7201
> > +      - nuvoton,nct7202
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  reset-gpios:
> > +    maxItems: 1
> > +
>
> Maybe this was brought up before, but no power supply?
>

  vdd-supply:
    description:
      A 3.3V to supply that powers the chip.

  vref-supply:
    description:
      The regulator supply for the ADC reference voltage.

> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +
> > +    #include <dt-bindings/gpio/gpio.h>
> > +    #include <dt-bindings/interrupt-controller/irq.h>
> > +
> > +    i2c {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        adc@1d {
> > +            compatible = "nuvoton,nct7202";
> > +            reg = <0x1d>;

            vdd-supply = <&vdd>;
            vref-supply = <&vref>;

> > +            interrupt-parent = <&gpio3>;
> > +            interrupts = <30 IRQ_TYPE_LEVEL_LOW>;
> > +            reset-gpios = <&gpio3 28 GPIO_ACTIVE_LOW>;
> > +        };
> > +    };
> > +...
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 3864d473f52f..fdc4aa5c7eff 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -2831,6 +2831,7 @@ L:      openbmc@lists.ozlabs.org (moderated for non-subscribers)
> >  S:   Supported
> >  F:   Documentation/devicetree/bindings/*/*/*npcm*
> >  F:   Documentation/devicetree/bindings/*/*npcm*
> > +F:   Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml

Remove F:   Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
>
> This (ARM/NUVOTON NPCM ARCHITECTURE) doesn't look like the right place for
> adding a stand-alone chip. You will need to start a new section like:
>
> NUVOTON NCT7201 IIO DRIVER
>

NUVOTON NCT7201 IIO DRIVER
M: Eason Yang <j2anfernee@gmail.com>
L: linux-iio@vger.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
F: drivers/iio/adc/nct7201.c

> >  F:   Documentation/devicetree/bindings/rtc/nuvoton,nct3018y.yaml
> >  F:   arch/arm/boot/dts/nuvoton/nuvoton-npcm*
> >  F:   arch/arm/mach-npcm/
>

Re: [PATCH v4 0/2] iio: adc: add Nuvoton NCT7201 ADC driver

[Yu-Hsian Yang]

Dear Jonathan,

Thanks again for the review

Jonathan Cameron <jic23@kernel.org> 於 2025年2月22日 週六 下午11:25寫道：
>
> On Fri, 21 Feb 2025 17:09:16 +0800
> Eason Yang <j2anfernee@gmail.com> wrote:
>
> Hi Eason,
>
> Not sure if I asked this before, but this is a device that seems
> to be typically used for hardware monitoring and there are a number
> of similar sounding device in drivers/hwmon/
>
> That raises a couple of questions:
> 1) Is it compatible with any of those existing drivers?

No, we need a new driver to do the ADC conversion for NCT7201/NCT7202.

> 2) Why IIO rather than HWMON?

A driver for NCT7201 with more functionality is available in the iio
adc subsystem.
If the chip is used for hardware monitoring, the iio->hwmon bridge
should be used.
>
> There isn't normally a problem with having a hardware monitoring
> related device supported by IIO, it is just good to know if your
> usecase makes that a good idea.  We have the iio-hwmon bridge
> driver to solve the problem of a device than can be used either
> as a generic ADC or as a hwmon type monitoring device (which tends
> to have more alarms etc)

Yes, we also verify the iio-hwmon bridge.

>
> Jonathan
>
>
> > Change since version 4:
> >  - Fix comments
> >  - Add interrupts and reset-gpios to the DT example
> >  - Use the FIELD_PREP and FIELD_GET
> >  - Add use_single_write in regmap_config
> >  - Use regmap_access_table
> >
> > Change since version 3:
> >  - Fix comments
> >  - Don't put nct720"x" in the name, just call it nct7201
> >  - Remove differential inputs until conversions are finished
> >  - Add NCT7201_ prefix in all macros and avoid the tables
> >  - Correct event threshold values in raw units
> >  - Add with and without interrupt callback function to have the event
> >    config part and one that doesn't
> >  - Remove print an error message if regmap_wirte failed case
> >
> > Change since version 2:
> >  - Remvoe read-vin-data-size property, default use read word vin data
> >  - Use regmap instead of i2c smbus API
> >  - IIO should be IIO_CHAN_INFO_RAW and _SCALE not _PROCESSED
> >  - Use dev_xxx_probe in probe function and dev_xxx in other functions
> >  - Use devm_iio_device_register replace of iio_device_register
> >  - Use guard(mutex) replace of mutex_lock
> >  - Use get_unaligned_le16 conversion API
> >
> > Changes since version 1:
> >  - Add new property in iio:adc binding document
> >  - Add new driver for Nuvoton NCT720x driver
> >
> > Eason Yang (2):
> >   dt-bindings: iio: adc: add NCT7201 ADCs
> >   iio: adc: add support for Nuvoton NCT7201
> >
> >  .../bindings/iio/adc/nuvoton,nct7201.yaml     |  57 ++
> >  MAINTAINERS                                   |   2 +
> >  drivers/iio/adc/Kconfig                       |  11 +
> >  drivers/iio/adc/Makefile                      |   1 +
> >  drivers/iio/adc/nct7201.c                     | 487 ++++++++++++++++++
> >  5 files changed, 558 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
> >  create mode 100644 drivers/iio/adc/nct7201.c
> >
>