[PATCH v9 0/2] iio: adc: add Nuvoton NCT7201 ADC driver

[PATCH v9 0/2] iio: adc: add Nuvoton NCT7201 ADC driver

[Eason Yang]

Change since version 9:
 - Fix comments
 - Change vin_mask and mask from CPU-endian to little-endian
 - Fix access to restricted __le16

Change since version 8:
 - dev_err_probe(), move the definition from device.h to dev_printk.h
 - Use USEC_PER_MSEC rather than the hard coded value of 1000
 - Use one dev for both regmap and regmap16

Change since version 7:
 - Fix comments
 - Derive dev from the respective regmap
 - Generate the mask from the number of voltage input channels 

Change since version 6:
 - Fix comments
 - Add use_single_read in regmap_config
 - Remove unused definitions
 - Do not shadow the return code by -EIO and let regmap API caller to decide
 - Use simple English in all error messages
 - Use a local variable for the struct device pointers. This increases 
   code readability with shortened lines.
 - Use `fsleep` instead of `mdelay`
 - Use 16 bits type __le16 instead of u8 data[2]

Change since version 5:
 - Fix comments
 - Add NUVOTON NCT7201 IIO DRIVER section in MAINTAINERS
 - Add vdd-supply and vref-supply to the DT example
 - Remove mutex since the regmap should already have an internal lock
 - Remove redundant assigning values
 - Check errors on regmap_write

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     |  70 +++
 MAINTAINERS                                   |   7 +
 drivers/iio/adc/Kconfig                       |  11 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/nct7201.c                     | 462 ++++++++++++++++++
 5 files changed, 551 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
 create mode 100644 drivers/iio/adc/nct7201.c

-- 
2.34.1

[PATCH v9 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>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 .../bindings/iio/adc/nuvoton,nct7201.yaml     | 70 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 76 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..8ce7d415d956
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,nct7201.yaml
@@ -0,0 +1,70 @@
+# 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.
+
+  NCT7201 contains 8 voltage monitor inputs (VIN1~VIN8).
+  NCT7202 contains 12 voltage monitor inputs (VIN1~VIN12).
+
+properties:
+  compatible:
+    enum:
+      - nuvoton,nct7201
+      - nuvoton,nct7202
+
+  reg:
+    maxItems: 1
+
+  vdd-supply:
+    description:
+      A 3.3V to supply that powers the chip.
+
+  vref-supply:
+    description:
+      The regulator supply for the ADC reference voltage.
+
+  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>;
+            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 69511c3b2b76..85b031ad7082 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17373,6 +17373,12 @@ F:	drivers/nubus/
 F:	include/linux/nubus.h
 F:	include/uapi/linux/nubus.h
 
+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
+
 NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
 M:	Antonino Daplas <adaplas@gmail.com>
 L:	linux-fbdev@vger.kernel.org
-- 
2.34.1

[PATCH v9 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 all the 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 are
supported.

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 | 462 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 475 insertions(+)
 create mode 100644 drivers/iio/adc/nct7201.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 85b031ad7082..065202ab8fe7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17378,6 +17378,7 @@ 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
 
 NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
 M:	Antonino Daplas <adaplas@gmail.com>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 6529df1a498c..6d6af1b51b5e 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1092,6 +1092,17 @@ config NAU7802
 	  To compile this driver as a module, choose M here: the
 	  module will be called nau7802.
 
+config NCT7201
+	tristate "Nuvoton Instruments NCT7201 and NCT7202 Power Monitor"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for the 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 3e918c3eec69..54e8a7541af6 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -97,6 +97,7 @@ 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..0dadf699162a
--- /dev/null
+++ b/drivers/iio/adc/nct7201.c
@@ -0,0 +1,462 @@
+// 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/bitfield.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.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_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			0x13
+#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)				(0x00 + i)
+#define NCT7201_REG_VIN_HIGH_LIMIT(i)			(0x20 + (i) * 2)
+#define NCT7201_REG_VIN_LOW_LIMIT(i)			(0x21 + (i) * 2)
+#define NCT7201_MAX_CHANNEL				12
+
+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_MAX_CHANNEL - 1)),
+	regmap_reg_range(NCT7201_REG_VIN_HIGH_LIMIT(0),
+			 NCT7201_REG_VIN_LOW_LIMIT(NCT7201_MAX_CHANNEL - 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_MAX_CHANNEL - 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_read = true,
+	.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 regmap *regmap;
+	struct regmap *regmap16;
+	int num_vin_channels;
+	__le16 vin_mask;
+};
+
+struct nct7201_adc_model_data {
+	const char *model_name;
+	const struct iio_chan_spec *channels;
+	unsigned 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(num)					\
+	{								\
+		.type = IIO_VOLTAGE,					\
+		.indexed = 1,						\
+		.channel = num + 1,					\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+		.address = num,						\
+		.event_spec = nct7201_events,				\
+		.num_event_specs = ARRAY_SIZE(nct7201_events),		\
+	}
+
+static const struct iio_chan_spec nct7201_channels[] = {
+	NCT7201_VOLTAGE_CHANNEL(0),
+	NCT7201_VOLTAGE_CHANNEL(1),
+	NCT7201_VOLTAGE_CHANNEL(2),
+	NCT7201_VOLTAGE_CHANNEL(3),
+	NCT7201_VOLTAGE_CHANNEL(4),
+	NCT7201_VOLTAGE_CHANNEL(5),
+	NCT7201_VOLTAGE_CHANNEL(6),
+	NCT7201_VOLTAGE_CHANNEL(7),
+};
+
+static const struct iio_chan_spec nct7202_channels[] = {
+	NCT7201_VOLTAGE_CHANNEL(0),
+	NCT7201_VOLTAGE_CHANNEL(1),
+	NCT7201_VOLTAGE_CHANNEL(2),
+	NCT7201_VOLTAGE_CHANNEL(3),
+	NCT7201_VOLTAGE_CHANNEL(4),
+	NCT7201_VOLTAGE_CHANNEL(5),
+	NCT7201_VOLTAGE_CHANNEL(6),
+	NCT7201_VOLTAGE_CHANNEL(7),
+	NCT7201_VOLTAGE_CHANNEL(8),
+	NCT7201_VOLTAGE_CHANNEL(9),
+	NCT7201_VOLTAGE_CHANNEL(10),
+	NCT7201_VOLTAGE_CHANNEL(11),
+};
+
+static int nct7201_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct nct7201_chip_info *chip = iio_priv(indio_dev);
+	unsigned int value;
+	int err;
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		err = regmap_read(chip->regmap16, NCT7201_REG_VIN(chan->address), &value);
+		if (err)
+			return err;
+		*val = FIELD_GET(NCT7201_REG_VIN_MASK, value);
+		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);
+	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);
+	else
+		err = regmap_read(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
+				  &value);
+	if (err)
+		return err;
+
+	*val = FIELD_GET(NCT7201_REG_VIN_MASK, value);
+
+	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);
+	int err;
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	if (info != IIO_EV_INFO_VALUE)
+		return -EOPNOTSUPP;
+
+	if (dir == IIO_EV_DIR_FALLING)
+		err = regmap_write(chip->regmap16, NCT7201_REG_VIN_LOW_LIMIT(chan->address),
+				   FIELD_PREP(NCT7201_REG_VIN_MASK, val));
+	else
+		err = regmap_write(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
+				   FIELD_PREP(NCT7201_REG_VIN_MASK, val));
+
+	return err;
+}
+
+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 !!(le16_to_cpu(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);
+	__le16 mask = cpu_to_le16(BIT(chan->address));
+	int err;
+
+	if (chan->type != IIO_VOLTAGE)
+		return -EOPNOTSUPP;
+
+	if (state)
+		chip->vin_mask |= mask;
+	else
+		chip->vin_mask &= ~mask;
+
+	if (chip->num_vin_channels <= 8)
+		err = regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE,
+				   le16_to_cpu(chip->vin_mask));
+	else
+		err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE,
+					&chip->vin_mask, sizeof(chip->vin_mask));
+
+	return err;
+}
+
+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)
+{
+	struct device *dev = regmap_get_device(chip->regmap);
+	__le16 data = cpu_to_le16(GENMASK(chip->num_vin_channels - 1, 0));
+	unsigned int value;
+	int err;
+
+	err = regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
+			   NCT7201_BIT_CONFIGURATION_RESET);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to reset chip\n");
+
+	/*
+	 * 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.
+	 */
+	fsleep(25 * USEC_PER_MSEC);
+
+	err = regmap_read(chip->regmap, NCT7201_REG_BUSY_STATUS, &value);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to read busy status\n");
+	if (!(value & NCT7201_BIT_PWR_UP))
+		return dev_err_probe(dev, -EIO, "Failed to power up after reset\n");
+
+	/* Enable Channels */
+	if (chip->num_vin_channels <= 8)
+		err = regmap_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE,
+				   le16_to_cpu(data));
+	else
+		err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE,
+					&data, sizeof(data));
+	if (err)
+		return dev_err_probe(dev, err, "Failed to enable channels\n");
+
+	err = regmap_bulk_read(chip->regmap, NCT7201_REG_CHANNEL_ENABLE,
+			       &chip->vin_mask, sizeof(chip->vin_mask));
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Failed to read channel enable register\n");
+
+	/* Start monitoring if needed */
+	err = regmap_set_bits(chip->regmap, NCT7201_REG_CONFIGURATION,
+			      NCT7201_BIT_CONFIGURATION_START);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to start monitoring\n");
+
+	return 0;
+}
+
+static int nct7201_probe(struct i2c_client *client)
+{
+	const struct nct7201_adc_model_data *model_data;
+	struct device *dev = &client->dev;
+	struct nct7201_chip_info *chip;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	model_data = i2c_get_match_data(client);
+	if (!model_data)
+		return -ENODEV;
+
+	indio_dev = devm_iio_device_alloc(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(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(dev, PTR_ERR(chip->regmap16),
+				     "Failed to init regmap16\n");
+
+	chip->num_vin_channels = model_data->num_vin_channels;
+
+	ret = nct7201_init_chip(chip);
+	if (ret)
+		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(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 v9 2/2] iio: adc: add support for Nuvoton NCT7201

[Jonathan Cameron]

On Mon,  5 May 2025 17:26:00 +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 all the 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 are
> supported.

As below. Setup of threshold events seems to be here, but not the interrupt
handler that would call iio_push_event() to actually notify userspace they
occurred.  Is the intent they are getting wired to something else?

Even if that is the intent we normally cross wire them to the host as well
so as to be able to find out what happened.  The use in here of client->irq
implies such wiring but no sign of it being handled.


Jonathan


> 
> 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 | 462 ++++++++++++++++++++++++++++++++++++++
>  4 files changed, 475 insertions(+)
>  create mode 100644 drivers/iio/adc/nct7201.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 85b031ad7082..065202ab8fe7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17378,6 +17378,7 @@ 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
>  
>  NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
>  M:	Antonino Daplas <adaplas@gmail.com>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 6529df1a498c..6d6af1b51b5e 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -1092,6 +1092,17 @@ config NAU7802
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called nau7802.
>  
> +config NCT7201
> +	tristate "Nuvoton Instruments NCT7201 and NCT7202 Power Monitor"
> +	depends on I2C
> +	select REGMAP_I2C
> +	help
> +	  If you say yes here you get support for the 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 3e918c3eec69..54e8a7541af6 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -97,6 +97,7 @@ 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..0dadf699162a
> --- /dev/null
> +++ b/drivers/iio/adc/nct7201.c
> @@ -0,0 +1,462 @@

> +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),
> +	},
I'd missed this before but you spend lots of time setting up event
detectors etc which all looks good, but where are they actually signalled?

The irq handler seems to be missing.

> +};

> +static int nct7201_init_chip(struct nct7201_chip_info *chip)
> +{
> +	struct device *dev = regmap_get_device(chip->regmap);
> +	__le16 data = cpu_to_le16(GENMASK(chip->num_vin_channels - 1, 0));
> +	unsigned int value;
> +	int err;
> +
> +	err = regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
> +			   NCT7201_BIT_CONFIGURATION_RESET);
> +	if (err)
> +		return dev_err_probe(dev, err, "Failed to reset chip\n");
> +
> +	/*
> +	 * 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.

Trivial but you don't "wait for it."  That's the right choice here but the comment is
misleading.

> +	 */
> +	fsleep(25 * USEC_PER_MSEC);
> +
> +	err = regmap_read(chip->regmap, NCT7201_REG_BUSY_STATUS, &value);
> +	if (err)
> +		return dev_err_probe(dev, err, "Failed to read busy status\n");
> +	if (!(value & NCT7201_BIT_PWR_UP))
> +		return dev_err_probe(dev, -EIO, "Failed to power up after reset\n");
> +

Re: [PATCH v9 2/2] iio: adc: add support for Nuvoton NCT7201

[Andy Shevchenko]

On Mon, May 05, 2025 at 05:26:00PM +0800, 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 all the 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 are
> supported.

...

> +#include <linux/array_size.h>
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/delay.h>
> +#include <linux/dev_printk.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>

+ time.h

> +#include <linux/types.h>
> +#include <linux/unaligned.h>

-- 
With Best Regards,
Andy Shevchenko