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 | 488 ++++++++++++++++++++++++++++++++++++++
4 files changed, 501 insertions(+)
create mode 100644 drivers/iio/adc/nct7201.c
diff --git a/MAINTAINERS b/MAINTAINERS
index f9ec68d4d8b4..d155780e5ee0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17307,6 +17307,7 @@ 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..fe1ac8a28ab6
--- /dev/null
+++ b/drivers/iio/adc/nct7201.c
@@ -0,0 +1,488 @@
+// 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/device.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_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 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(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 < 0)
+ 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);
+ if (err < 0)
+ return err;
+ } else {
+ err = regmap_read(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
+ &value);
+ if (err < 0)
+ 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 = 0;
+
+ 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));
+ if (err < 0)
+ return err;
+ } else {
+ err = regmap_write(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
+ FIELD_PREP(NCT7201_REG_VIN_MASK, val));
+ if (err < 0)
+ return err;
+ }
+
+ 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;
+ int err;
+
+ if (chan->type != IIO_VOLTAGE)
+ return -EOPNOTSUPP;
+
+ mask = BIT(chan->address);
+
+ 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_1,
+ chip->vin_mask);
+ if (err < 0)
+ return err;
+ } else {
+ err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
+ &chip->vin_mask, sizeof(chip->vin_mask));
+ if (err < 0)
+ return err;
+ }
+
+ 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] = {0};
+ unsigned int value;
+ int err;
+
+ err = regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
+ NCT7201_BIT_CONFIGURATION_RESET);
+ if (err < 0)
+ return dev_err_probe(&chip->client->dev, -EIO,
+ "Failed to write NCT7201_REG_CONFIGURATION\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.
+ */
+ 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");
+ }
+ chip->vin_mask = get_unaligned_le16(data);
+
+ /* 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;
+
+ 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");
--
2.34.1On Wed, Apr 09, 2025 at 09:23:51AM +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/device.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>
...
> +#define NCT7201_VIN_MAX 12
Is this in volts? Can you add a unit suffix?
...
> +#define NCT7201_IN_SCALING 4995
Interesting number, just want to confirm it's indeed 4995 and not 4095.
...
> +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);
> + if (err < 0)
> + return err;
> + } else {
> + err = regmap_read(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> + &value);
> + if (err < 0)
> + return err;
> + }
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;
Here and elsewhere why ' < 0' is used? Do you expect positive return values
from those?
> + *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 = 0;
Useless assignment.
> + 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));
> + if (err < 0)
> + return err;
> + } else {
> + err = regmap_write(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> + FIELD_PREP(NCT7201_REG_VIN_MASK, val));
> + if (err < 0)
> + return err;
> + }
> +
> + return 0;
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_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;
> + int err;
> +
> + if (chan->type != IIO_VOLTAGE)
> + return -EOPNOTSUPP;
> +
> + mask = BIT(chan->address);
> +
> + 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_1,
> + chip->vin_mask);
> + if (err < 0)
> + return err;
> + } else {
> + err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
> + &chip->vin_mask, sizeof(chip->vin_mask));
> + if (err < 0)
> + return err;
> + }
> +
> + return 0;
Same as above.
> +}
...
> +static int nct7201_init_chip(struct nct7201_chip_info *chip)
> +{
> + u8 data[2] = {0};
'0' is not needed. Shouldn't this be __le16 or __be16 instead?
> + unsigned int value;
> + int err;
> +
> + err = regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
> + NCT7201_BIT_CONFIGURATION_RESET);
> + if (err < 0)
> + return dev_err_probe(&chip->client->dev, -EIO,
struct device *dev = &chip->client->dev;
at the top of the function will help a lot in tiding up the below code.
Shadowed error code, why?
> + "Failed to write NCT7201_REG_CONFIGURATION\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.
> + */
> + mdelay(25);
No sleep? Why? Can't you use fsleep()?
> + 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,
Shadowed error code, why?
> + "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,
Why error code is shadowed?
> + "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,
Ditto.
> + "Failed to write NCT7201_REG_CHANNEL_ENABLE_1 and NCT7201_REG_CHANNEL_ENABLE_2\n");
> + }
Just make it 16-bit type, define one value and use just simple English
in the error message: "Failed to write channel enable mask\n");
Same to all your error messages.
> + chip->vin_mask = get_unaligned_le16(data);
> +
> + /* 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;
No error check? Why?
> +}
...
> +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 -EINVAL;
ENODEV is more suitable here.
> +
> + 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;
> + chip->client = client;
How exactly is _client_ used elsewhere? Shouldn't it be just a struct device
pointer?
> + ret = nct7201_init_chip(chip);
> + if (ret < 0)
Do you expect positive returned values? What is their meaning?
Why do you skip them?
> + 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);
> +}
--
With Best Regards,
Andy Shevchenko
Dear Andy,
Thanks for the review and the comments.
Will fix all.
Andy Shevchenko <andriy.shevchenko@linux.intel.com> 於 2025年4月10日 週四 上午12:19寫道：
>
> On Wed, Apr 09, 2025 at 09:23:51AM +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/device.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>
>
> ...
>
> > +#define NCT7201_VIN_MAX 12
>
> Is this in volts? Can you add a unit suffix?
Rename it as
#define NCT7201_MAX_CHANNEL 12
>
> ...
>
> > +#define NCT7201_IN_SCALING 4995
> > +#define NCT720X_IN_SCALING_FACTOR 10000
> Interesting number, just want to confirm it's indeed 4995 and not 4095.
>
These definitions are for real voltage calculations,
the formula is Voltage(V) = 13bitCountValue * 0.0004995
However, the definitions are not used anymore.
So remove them.
> ...
>
> > +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);
> > + if (err < 0)
> > + return err;
> > + } else {
> > + err = regmap_read(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> > + &value);
> > + if (err < 0)
> > + return err;
> > + }
>
> 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;
>
> Here and elsewhere why ' < 0' is used? Do you expect positive return values
> from those?
>
In regmap_read function, A value of zero will be returned on success,
a negative errno will be returned in error cases.
We don't have a positive return case.
> > + *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 = 0;
>
> Useless assignment.
>
> > + 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));
> > + if (err < 0)
> > + return err;
> > + } else {
> > + err = regmap_write(chip->regmap16, NCT7201_REG_VIN_HIGH_LIMIT(chan->address),
> > + FIELD_PREP(NCT7201_REG_VIN_MASK, val));
> > + if (err < 0)
> > + return err;
> > + }
> > +
> > + return 0;
>
> 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_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;
> > + int err;
> > +
> > + if (chan->type != IIO_VOLTAGE)
> > + return -EOPNOTSUPP;
> > +
> > + mask = BIT(chan->address);
> > +
> > + 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_1,
> > + chip->vin_mask);
> > + if (err < 0)
> > + return err;
> > + } else {
> > + err = regmap_bulk_write(chip->regmap, NCT7201_REG_CHANNEL_ENABLE_1,
> > + &chip->vin_mask, sizeof(chip->vin_mask));
> > + if (err < 0)
> > + return err;
> > + }
> > +
> > + return 0;
>
> Same as above.
>
> > +}
>
> ...
>
> > +static int nct7201_init_chip(struct nct7201_chip_info *chip)
> > +{
> > + u8 data[2] = {0};
>
> '0' is not needed. Shouldn't this be __le16 or __be16 instead?
>
+ __be16 data = NCT7201_REG_CHANNEL_ENABLE_MASK;
> > + unsigned int value;
> > + int err;
> > +
> > + err = regmap_write(chip->regmap, NCT7201_REG_CONFIGURATION,
> > + NCT7201_BIT_CONFIGURATION_RESET);
> > + if (err < 0)
> > + return dev_err_probe(&chip->client->dev, -EIO,
>
> struct device *dev = &chip->client->dev;
>
> at the top of the function will help a lot in tiding up the below code.
>
> Shadowed error code, why?
>
Do not shadow the return code by -EIO and let the regmap API caller decide.
> > + "Failed to write NCT7201_REG_CONFIGURATION\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.
> > + */
> > + mdelay(25);
>
> No sleep? Why? Can't you use fsleep()?
>
+ msleep(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,
>
> Shadowed error code, why?
Do not shadow the return code by -EIO and let the regmap API caller decide.
>
> > + "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,
>
> Why error code is shadowed?
>
Do not shadow the return code by -EIO and let the regmap API caller decide.
> > + "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,
>
> Ditto.
>
> > + "Failed to write NCT7201_REG_CHANNEL_ENABLE_1 and NCT7201_REG_CHANNEL_ENABLE_2\n");
> > + }
>
> Just make it 16-bit type, define one value and use just simple English
> in the error message: "Failed to write channel enable mask\n");
>
> Same to all your error messages.
>
We would examine all the error messages in simple English.
> > + chip->vin_mask = get_unaligned_le16(data);
> > +
> > + /* 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;
>
> No error check? Why?
>
+ 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");
> > +}
>
> ...
>
> > +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 -EINVAL;
>
> ENODEV is more suitable here.
>
+ return -ENODEV
> > +
> > + 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;
>
> > + chip->client = client;
>
> How exactly is _client_ used elsewhere? Shouldn't it be just a struct device
> pointer?
Yes, it is just a struct device pointer.
In nct7201_init_chip(chip), we would use the chip->client->dev as
dev_err_probe() parameter
>
> > + ret = nct7201_init_chip(chip);
> > + if (ret < 0)
>
> Do you expect positive returned values? What is their meaning?
> Why do you skip them?
>
No, we don't expect positive return values.
> > + 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);
> > +}
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
On Mon, Apr 14, 2025 at 09:40:35PM +0800, Yu-Hsian Yang wrote: > Andy Shevchenko <andriy.shevchenko@linux.intel.com> 於 2025年4月10日 週四 上午12:19寫道： > > On Wed, Apr 09, 2025 at 09:23:51AM +0800, Eason Yang wrote: ... > > Here and elsewhere why ' < 0' is used? Do you expect positive return values > > from those? > > In regmap_read function, A value of zero will be returned on success, > a negative errno will be returned in error cases. > We don't have a positive return case. So, can we remove ' < 0' parts where they are not required, please? ... > > > + chip->client = client; > > > > How exactly is _client_ used elsewhere? Shouldn't it be just a struct device > > pointer? > > Yes, it is just a struct device pointer. > In nct7201_init_chip(chip), we would use the chip->client->dev as > dev_err_probe() parameter Just save there struct device *dev and use chip->dev instead. -- With Best Regards, Andy Shevchenko
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