[PATCH v2 2/2] iio: adc: add Nuvoton NCT720x ADC driver
Yu-Hsian Yang
j2anfernee at gmail.com
Tue Dec 10 16:20:45 AEDT 2024
Dear David Lechner,
Thanks for your comment.
David Lechner <dlechner at baylibre.com> 於 2024年12月6日 週五 上午2:22寫道：
>
> On 12/3/24 3:15 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.
>
> In the code, there are channels set up for differential inputs. Should we
> remove these until conversion and event support for them is added?
>
Okay, I would remove differential inputs until conversions are finished.
> >
> > Signed-off-by: Eason Yang <j2anfernee at gmail.com>
> > ---
> > MAINTAINERS | 1 +
> > drivers/iio/adc/Kconfig | 10 +
> > drivers/iio/adc/Makefile | 1 +
> > drivers/iio/adc/nct720x.c | 533 ++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 545 insertions(+)
> > create mode 100644 drivers/iio/adc/nct720x.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index bea10a846475..573b12f0cd4d 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -2799,6 +2799,7 @@ F: arch/arm/mach-npcm/
> > F: arch/arm64/boot/dts/nuvoton/
> > F: drivers/*/*/*npcm*
> > F: drivers/*/*npcm*
> > +F: drivers/iio/adc/nct720x.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..6eed518efa1c 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -1048,6 +1048,16 @@ config NAU7802
> > To compile this driver as a module, choose M here: the
> > module will be called nau7802.
> >
> > +config NCT720X
> > + 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 nct720x.
>
> Don't put "x" in the name, just call it nct7201. We always try to avoid
> using "x" in the IIO subsystem because too often it causes problems in
> the future.
>
Understand it, we would use nct7201 to replace nct720x for all parts.
> > +
> > 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..89f5b5d1a567 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-$(CONFIG_NCT720X) += nct720x.o
> > obj-$(CONFIG_NPCM_ADC) += npcm_adc.o
> > obj-$(CONFIG_PAC1921) += pac1921.o
> > obj-$(CONFIG_PAC1934) += pac1934.o
> > diff --git a/drivers/iio/adc/nct720x.c b/drivers/iio/adc/nct720x.c
> > new file mode 100644
> > index 000000000000..b28b5f4d7d70
> > --- /dev/null
> > +++ b/drivers/iio/adc/nct720x.c
> > @@ -0,0 +1,533 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Driver for Nuvoton nct7201 and nct7202 power monitor chips.
> > + *
> > + * Copyright (c) 2024 Nuvoton Inc.
>
> If there are datasheets available, it would be helpful to link to them here.
>
We would check the chip vendor.
> > + */
> > +
> > +#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>
> > +#include <linux/iio/sysfs.h>
>
> Unused header.
>
- #include <linux/iio/sysfs.h>
> > +
> > +#define VIN_MAX 12 /* Counted from 1 */
> > +#define NCT720X_IN_SCALING 4995
> > +#define NCT720X_IN_SCALING_FACTOR 10000
> > +
> > +#define REG_INTERRUPT_STATUS_1 0x0C
> > +#define REG_INTERRUPT_STATUS_2 0x0D
> > +#define REG_VOLT_LOW_BYTE 0x0F
> > +#define REG_CONFIGURATION 0x10
> > +#define BIT_CONFIGURATION_START BIT(0)
> > +#define BIT_CONFIGURATION_ALERT_MSK BIT(1)
> > +#define BIT_CONFIGURATION_CONV_RATE BIT(2)
> > +#define BIT_CONFIGURATION_RESET BIT(7)
> > +
> > +#define REG_ADVANCED_CONFIGURATION 0x11
> > +#define BIT_ADVANCED_CONF_MOD_ALERT BIT(0)
> > +#define BIT_ADVANCED_CONF_MOD_STS BIT(1)
> > +#define BIT_ADVANCED_CONF_FAULT_QUEUE BIT(2)
> > +#define BIT_ADVANCED_CONF_EN_DEEP_SHUTDOWN BIT(4)
> > +#define BIT_ADVANCED_CONF_EN_SMB_TIMEOUT BIT(5)
> > +#define BIT_ADVANCED_CONF_MOD_RSTIN BIT(7)
> > +
> > +#define REG_CHANNEL_INPUT_MODE 0x12
> > +#define REG_CHANNEL_ENABLE_1 0x13
> > +#define REG_CHANNEL_ENABLE_1_MASK GENMASK(7, 0)
> > +#define REG_CHANNEL_ENABLE_2 0x14
> > +#define REG_CHANNEL_ENABLE_2_MASK GENMASK(3, 0)
> > +#define REG_INTERRUPT_MASK_1 0x15
> > +#define REG_INTERRUPT_MASK_2 0x16
> > +#define REG_BUSY_STATUS 0x1E
> > +#define BIT_BUSY BIT(0)
> > +#define BIT_PWR_UP BIT(1)
> > +#define REG_ONE_SHOT 0x1F
> > +#define REG_SMUS_ADDRESS 0xFC
> > +#define REG_VIN_LIMIT_LSB_MASK GENMASK(4, 0)
> > +
> > +static const u8 REG_VIN[VIN_MAX] = {
>
> Usually ALL_CAPS is reserved for macros and static const data is
> lower_snake_case. Plus, prefer to always add the driver name as
> a namespace to help avoid conflics with more generic names.
>
> Example:
>
> static const u8 nct7201_reg_vin[NCT7201_VIN_MAX] = {
>
> Or (even better IMHO) just turn these into macros and avoid
> the tables:
>
> #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)
>
Add prefix NCT7201_ in above all above define and use macros to avoid
the tables, like below
#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)
#define NCT7201_REG_VIN_HIGH_LIMIT_LSB(i) (0x40 + (i) * 2)
#define NCT7201_REG_VIN_LOW_LIMIT_LSB(i) (0x41 + (i) * 2)
> > + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0 -7 */
> > + 0x08, 0x09, 0x0A, 0x0B, /* 8 - 11 */
> > +};
> > +static const u8 REG_VIN_HIGH_LIMIT[VIN_MAX] = {
> > + 0x20, 0x22, 0x24, 0x26, 0x28, 0x2A, 0x2C, 0x2E,
> > + 0x30, 0x32, 0x34, 0x36,
> > +};
> > +static const u8 REG_VIN_LOW_LIMIT[VIN_MAX] = {
> > + 0x21, 0x23, 0x25, 0x27, 0x29, 0x2B, 0x2D, 0x2F,
> > + 0x31, 0x33, 0x35, 0x37,
> > +};
> > +static const u8 REG_VIN_HIGH_LIMIT_LSB[VIN_MAX] = {
> > + 0x40, 0x42, 0x44, 0x46, 0x48, 0x4A, 0x4C, 0x4E,
> > + 0x50, 0x52, 0x54, 0x56,
> > +};
> > +static const u8 REG_VIN_LOW_LIMIT_LSB[VIN_MAX] = {
> > + 0x41, 0x43, 0x45, 0x47, 0x49, 0x4B, 0x4D, 0x4F,
> > + 0x51, 0x53, 0x55, 0x57,
> > +};
> > +static u8 nct720x_chan_to_index[] = {
>
> Should be const. Although, even better, just store this value in
> the address field, then we don't need the translation table.
>
> Right now, the address is always the same as the channel, so it
> is redundant anyway.
>
Remove nct720x_chan_to_index tables.
> > + 0 /* Not used */, 0, 1, 2, 3, 4, 5, 6,
> > + 7, 8, 9, 10, 11,
> > +};
> > +
> > +struct nct720x_chip_info {
> > + struct i2c_client *client;
> > + struct mutex access_lock; /* for multi-byte read and write operations */
> > + struct regmap *regmap;
> > + struct regmap *regmap16;
> > + int vin_max; /* number of VIN channels */
>
> We could rename this to num_vin_channels, then we wouldn't need
> a comment to explain it.
>
Okay, rename vin_max to num_vin_channels
> > + u32 vin_mask;
> > +};
> > +
> > +struct nct720x_adc_model_data {
> > + const char *model_name;
> > + const struct iio_chan_spec *channels;
> > + const int num_channels;
> > + int vin_max;
> > +};
Rename vin_max to num_vin_channels
> > +
> > +static const struct iio_event_spec nct720x_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 NCT720X_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 = nct720x_events, \
> > + .num_event_specs = ARRAY_SIZE(nct720x_events), \
> > + }
> > +
> > +#define NCT720X_VOLTAGE_CHANNEL_DIFF(chan1, chan2, addr) \
> > + { \
> > + .type = IIO_VOLTAGE, \
> > + .indexed = 1, \
> > + .channel = (chan1), \
> > + .channel2 = (chan2), \
> > + .differential = 1, \
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> > + .address = addr, \
> > + .event_spec = nct720x_events, \
> > + .num_event_specs = ARRAY_SIZE(nct720x_events), \
> > + }
> > +
> > +static const struct iio_chan_spec nct7201_channels[] = {
> > + NCT720X_VOLTAGE_CHANNEL(1, 1),
> > + NCT720X_VOLTAGE_CHANNEL(2, 2),
> > + NCT720X_VOLTAGE_CHANNEL(3, 3),
> > + NCT720X_VOLTAGE_CHANNEL(4, 4),
> > + NCT720X_VOLTAGE_CHANNEL(5, 5),
> > + NCT720X_VOLTAGE_CHANNEL(6, 6),
> > + NCT720X_VOLTAGE_CHANNEL(7, 7),
> > + NCT720X_VOLTAGE_CHANNEL(8, 8),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(1, 2, 1),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(3, 4, 3),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(5, 6, 5),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(7, 8, 7),
> > +};
Remove differential inputs.
- NCT720X_VOLTAGE_CHANNEL_DIFF(1, 2, 1),
- NCT720X_VOLTAGE_CHANNEL_DIFF(3, 4, 3),
- NCT720X_VOLTAGE_CHANNEL_DIFF(5, 6, 5),
- NCT720X_VOLTAGE_CHANNEL_DIFF(7, 8, 7),
> > +
> > +static const struct iio_chan_spec nct7202_channels[] = {
> > + NCT720X_VOLTAGE_CHANNEL(1, 1),
> > + NCT720X_VOLTAGE_CHANNEL(2, 2),
> > + NCT720X_VOLTAGE_CHANNEL(3, 3),
> > + NCT720X_VOLTAGE_CHANNEL(4, 4),
> > + NCT720X_VOLTAGE_CHANNEL(5, 5),
> > + NCT720X_VOLTAGE_CHANNEL(6, 6),
> > + NCT720X_VOLTAGE_CHANNEL(7, 7),
> > + NCT720X_VOLTAGE_CHANNEL(8, 8),
> > + NCT720X_VOLTAGE_CHANNEL(9, 9),
> > + NCT720X_VOLTAGE_CHANNEL(10, 10),
> > + NCT720X_VOLTAGE_CHANNEL(11, 11),
> > + NCT720X_VOLTAGE_CHANNEL(12, 12),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(1, 2, 1),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(3, 4, 3),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(5, 6, 5),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(7, 8, 7),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(9, 10, 9),
> > + NCT720X_VOLTAGE_CHANNEL_DIFF(11, 12, 11),
> > +};
Remove differential inputs.
- NCT720X_VOLTAGE_CHANNEL_DIFF(1, 2, 1),
- NCT720X_VOLTAGE_CHANNEL_DIFF(3, 4, 3),
- NCT720X_VOLTAGE_CHANNEL_DIFF(5, 6, 5),
- NCT720X_VOLTAGE_CHANNEL_DIFF(7, 8, 7),
- NCT720X_VOLTAGE_CHANNEL_DIFF(9, 10, 9),
- NCT720X_VOLTAGE_CHANNEL_DIFF(11, 12, 11),
> > +static int nct720x_read_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + int index = nct720x_chan_to_index[chan->address];
> > + u16 volt;
> > + unsigned int value;
> > + int err;
> > + struct nct720x_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, REG_VIN[index], &value);
> > + if (err < 0)
> > + return err;
> > + volt = (u16)value;
> > + *val = volt >> 3;
>
> It seems strange that this is 13 bits when the chips are 8 and 12 bit.
>
> > + return IIO_VAL_INT;
> > + case IIO_CHAN_INFO_SCALE:
> > + /* From the datasheet, we have to multiply by 0.0004995 */
>
> The scale is the same for both 8 bit and 12 bit chips?
>
> > + *val = 0;
> > + *val2 = 499500;
> > + return IIO_VAL_INT_PLUS_NANO;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +static int nct720x_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 nct720x_chip_info *chip = iio_priv(indio_dev);
> > + u16 volt;
> > + unsigned int value;
> > + int tmp, err;
> > + int index = nct720x_chan_to_index[chan->address];
> > +
> > + if (chan->type != IIO_VOLTAGE)
> > + return -EOPNOTSUPP;
> > +
> > + if (info != IIO_EV_INFO_VALUE)
> > + return -EINVAL;
>
> Do we need guard(mutex)(&chip->access_lock); here?
>
No, if read word, we don't need mutex here.
> > +
> > + if (dir == IIO_EV_DIR_FALLING) {
> > + err = regmap_read(chip->regmap16, REG_VIN_LOW_LIMIT[index], &value);
> > + if (err < 0)
> > + return err;
> > + volt = (u16)value;
> > + } else {
> > + err = regmap_read(chip->regmap16, REG_VIN_HIGH_LIMIT[index], &value);
> > + if (err < 0)
> > + return err;
> > + volt = (u16)value;
> > + }
> > +
> > + /* Voltage(V) = 13bitCountValue * 0.0004995 */
> > + tmp = (volt >> 3) * NCT720X_IN_SCALING;
> > + *val = tmp / NCT720X_IN_SCALING_FACTOR;
>
> I'm pretty sure event threshold values need to be in raw units to match
> the `in_voltageY_raw` attributes, so the scaling factor would not be
> applied here.
>
- /* Voltage(V) = 13bitCountValue * 0.0004995 */
- tmp = (volt >> 3) * NCT720X_IN_SCALING;
- val = tmp / NCT720X_IN_SCALING_FACTOR;
+ *val = volt >> 3;
> > +
> > + return IIO_VAL_INT;
> > +}
> > +
> > +static int nct720x_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 nct720x_chip_info *chip = iio_priv(indio_dev);
> > + int index, err = 0;
> > + long v1, v2, volt;
> > +
> > + index = nct720x_chan_to_index[chan->address];
> > + volt = (val * NCT720X_IN_SCALING_FACTOR) / NCT720X_IN_SCALING;
>
> Same applies here.
>
- long v1, v2, volt;
+ long v1, v2;
- volt = (val * NCT720X_IN_SCALING_FACTOR) / NCT720X_IN_SCALING;
> > + v1 = volt >> 5;
> > + v2 = (volt & REG_VIN_LIMIT_LSB_MASK) << 3;
>
> Looks like FIELD_PREP() could be used here.
>
- v1 = volt >> 5;
- v2 = (volt & REG_VIN_LIMIT_LSB_MASK) << 3;
+ v1 = val >> 5;
+ v2 = FIELD_PREP(NCT7201_REG_VIN_LIMIT_LSB_MASK, val) << 3;
> > +
> > + if (chan->type != IIO_VOLTAGE)
> > + return -EOPNOTSUPP;
> > +
> > + if (info == IIO_EV_INFO_VALUE) {
> > + if (dir == IIO_EV_DIR_FALLING) {
> > + guard(mutex)(&chip->access_lock);
> > + err = regmap_write(chip->regmap, REG_VIN_LOW_LIMIT[index], v1);
> > + if (err < 0)
> > + dev_err(&indio_dev->dev, "Failed to write REG_VIN%d_LOW_LIMIT\n",
> > + index + 1);
> > +
> > + err = regmap_write(chip->regmap, REG_VIN_LOW_LIMIT_LSB[index], v2);
> > + if (err < 0)
> > + dev_err(&indio_dev->dev, "Failed to write REG_VIN%d_LOW_LIMIT_LSB\n",
> > + index + 1);
> > +
> > + } else {
> > + guard(mutex)(&chip->access_lock);
> > + err = regmap_write(chip->regmap, REG_VIN_HIGH_LIMIT[index], v1);
> > + if (err < 0)
> > + dev_err(&indio_dev->dev, "Failed to write REG_VIN%d_HIGH_LIMIT\n",
> > + index + 1);
> > +
> > + err = regmap_write(chip->regmap, REG_VIN_HIGH_LIMIT_LSB[index], v2);
> > + if (err < 0)
> > + dev_err(&indio_dev->dev, "Failed to write REG_VIN%d_HIGH_LIMIT_LSB\n",
> > + index + 1);
> > + }
> > + }
> > + return err;
> > +}
> > +
> > +static int nct720x_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 nct720x_chip_info *chip = iio_priv(indio_dev);
> > + int index = nct720x_chan_to_index[chan->address];
> > +
> > + if (chan->type != IIO_VOLTAGE)
> > + return -EOPNOTSUPP;
> > +
> > + return !!(chip->vin_mask & BIT(index));
> > +}
> > +
> > +static int nct720x_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)
> > +{
> > + int err = 0;
> > + struct nct720x_chip_info *chip = iio_priv(indio_dev);
> > + int index = nct720x_chan_to_index[chan->address];
> > + unsigned int mask;
> > +
> > + if (chan->type != IIO_VOLTAGE)
> > + return -EOPNOTSUPP;
> > +
> > + mask = BIT(index);
> > +
> > + if (!state && (chip->vin_mask & mask))
> > + chip->vin_mask &= ~mask;
> > + else if (state && !(chip->vin_mask & mask))
> > + chip->vin_mask |= mask;
> > +
> > + guard(mutex)(&chip->access_lock);
> > +
> > + err = regmap_write(chip->regmap, REG_CHANNEL_ENABLE_1,
> > + chip->vin_mask & REG_CHANNEL_ENABLE_1_MASK);
> > + if (err < 0)
> > + dev_err(&indio_dev->dev, "Failed to write REG_CHANNEL_ENABLE_1\n");
> > +
> > + if (chip->vin_max == 12) {
> > + err = regmap_write(chip->regmap, REG_CHANNEL_ENABLE_2, chip->vin_mask >> 8);
> > + if (err < 0)
> > + dev_err(&indio_dev->dev, "Failed to write REG_CHANNEL_ENABLE_2\n");
> > + }
> > + return err;
> > +}
> > +
> > +static const struct iio_info nct720x_info = {
> > + .read_raw = nct720x_read_raw,
> > + .read_event_config = nct720x_read_event_config,
> > + .write_event_config = nct720x_write_event_config,
> > + .read_event_value = nct720x_read_event_value,
> > + .write_event_value = nct720x_write_event_value,
> > +};
> > +
> > +static const struct nct720x_adc_model_data nct7201_model_data = {
> > + .model_name = "nct7201",
> > + .channels = nct7201_channels,
> > + .num_channels = ARRAY_SIZE(nct7201_channels),
> > + .vin_max = 8,
> > +};
> > +
> > +static const struct nct720x_adc_model_data nct7202_model_data = {
> > + .model_name = "nct7202",
> > + .channels = nct7202_channels,
> > + .num_channels = ARRAY_SIZE(nct7202_channels),
> > + .vin_max = 12,
> > +};
> > +
> > +static int nct720x_init_chip(struct nct720x_chip_info *chip)
> > +{
> > + u8 data[2];
> > + unsigned int value;
> > + int err;
> > +
> > + err = regmap_write(chip->regmap, REG_CONFIGURATION, BIT_CONFIGURATION_RESET);
> > + if (err) {
> > + dev_err(&chip->client->dev, "Failed to write REG_CONFIGURATION\n");
> > + return err;
>
> Better would be `return dev_err_probe()`. But it is very rare for
> regmap_write() to fail so usually we don't print an error message
> for these.
>
We would remove print an error message for all remap_write failed.
> > + }
> > +
> > + /*
> > + * 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.
>
> I don't see anything that looks like waiting after checking the power
> up bit.
>
Since 25 msecs is simulated by HW in the lab for all registers can be accessed.
Then we would check one register if it is ready to access,
> > + */
> > + mdelay(25);
> > + err = regmap_read(chip->regmap, REG_BUSY_STATUS, &value);
> > + if (err < 0)
> > + return err;
> > + if (!(value & BIT_PWR_UP))
> > + return err;
>
> Won't this return 0? It seems like it should be returning an error code.
>
> Better would be something like:
>
> return dev_err_probe(dev, -EIO, "failed to power up after reset\n");
>
Thanks for your comment.
- return err;
+ return dev_err_probe(&chip->client->dev, -EIO, "failed to power up
after reset\n");
> > +
> > + /* Enable Channel */
> > + err = regmap_write(chip->regmap, REG_CHANNEL_ENABLE_1, REG_CHANNEL_ENABLE_1_MASK);
> > + if (err) {
> > + dev_err(&chip->client->dev, "Failed to write REG_CHANNEL_ENABLE_1\n");
> > + return err;
> > + }
> > +
> > + if (chip->vin_max == 12) {
> > + err = regmap_write(chip->regmap, REG_CHANNEL_ENABLE_2, REG_CHANNEL_ENABLE_2_MASK);
> > + if (err) {
> > + dev_err(&chip->client->dev, "Failed to write REG_CHANNEL_ENABLE_2\n");
> > + return err;
> > + }
> > + }
> > +
> > + guard(mutex)(&chip->access_lock);
>
> Why guard here and not before other regmap access in this function?
>
> Since this is only called during probe, we probably don't need the guard.
>
Okay.
> > + err = regmap_read(chip->regmap, REG_CHANNEL_ENABLE_1, &value);
> > + if (err < 0)
> > + return err;
> > + data[0] = (u8)value;
> > +
> > + err = regmap_read(chip->regmap, REG_CHANNEL_ENABLE_2, &value);
> > + if (err < 0)
> > + return err;
> > + data[1] = (u8)value;
> > +
> > + value = get_unaligned_le16(data);
> > + chip->vin_mask = value;
> > +
> > + /* Start monitoring if needed */
> > + err = regmap_read(chip->regmap, REG_CONFIGURATION, &value);
> > + if (err < 0) {
> > + dev_err(&chip->client->dev, "Failed to read REG_CONFIGURATION\n");
> > + return value;
> > + }
> > +
> > + value |= BIT_CONFIGURATION_START;
> > + err = regmap_write(chip->regmap, REG_CONFIGURATION, value);
> > + if (err < 0) {
> > + dev_err(&chip->client->dev, "Failed to write REG_CONFIGURATION\n");
> > + return err;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static const struct regmap_config nct720x_regmap8_config = {
> > + .name = "vin-data-read-byte",
> > + .reg_bits = 8,
> > + .val_bits = 8,
> > + .max_register = 0xff,
> > + .cache_type = REGCACHE_NONE,
> > +};
> > +
> > +static const struct regmap_config nct720x_regmap16_config = {
> > + .name = "vin-data-read-word",
> > + .reg_bits = 8,
> > + .val_bits = 16,
> > + .max_register = 0xff,
> > + .cache_type = REGCACHE_NONE,
>
> REGCACHE_NONE is the default, so can be omitted.
>
Remove it.
> > +};
> > +
> > +static int nct720x_probe(struct i2c_client *client)
> > +{
> > + const struct nct720x_adc_model_data *model_data;
> > + struct nct720x_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, &nct720x_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, &nct720x_regmap16_config);
> > + if (IS_ERR(chip->regmap16))
> > + return dev_err_probe(&client->dev, PTR_ERR(chip->regmap16),
> > + "Failed to init regmap16\n");
> > +
> > + chip->vin_max = model_data->vin_max;
> > +
> > + ret = devm_mutex_init(&client->dev, &chip->access_lock);
> > + if (ret)
> > + return ret;
> > +
> > + chip->client = client;
> > +
> > + ret = nct720x_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;
> > + indio_dev->info = &nct720x_info;
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > +
> > + return devm_iio_device_register(&client->dev, indio_dev);
> > +}
> > +
> > +static const struct i2c_device_id nct720x_id[] = {
> > + { "nct7201", (kernel_ulong_t)&nct7201_model_data },
> > + { "nct7202", (kernel_ulong_t)&nct7202_model_data },
>
> To be consistent with [1], please add .name = and .driver_data = in this table.
>
> [1]: https://lore.kernel.org/linux-iio/20241204150036.1695824-2-u.kleine-koenig@baylibre.com/
>
- { "nct7201", (kernel_ulong_t)&nct7201_model_data },
- { "nct7202", (kernel_ulong_t)&nct7202_model_data },
+ { .name = "nct7201", .driver_data = (kernel_ulong_t)&nct7201_model_data },
+ { .name = "nct7202", .driver_data = (kernel_ulong_t)&nct7202_model_data },
> > + { }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, nct720x_id);
> > +
> > +static const struct of_device_id nct720x_of_match[] = {
> > + {
> > + .compatible = "nuvoton,nct7201",
> > + .data = &nct7201_model_data,
> > + },
> > + {
> > + .compatible = "nuvoton,nct7202",
> > + .data = &nct7202_model_data,
> > + },
> > + { }
> > +};
> > +MODULE_DEVICE_TABLE(of, nct720x_of_match);
> > +
> > +static struct i2c_driver nct720x_driver = {
> > + .driver = {
> > + .name = "nct720x",
> > + .of_match_table = nct720x_of_match,
> > + },
> > + .probe = nct720x_probe,
> > + .id_table = nct720x_id,
> > +};
> > +module_i2c_driver(nct720x_driver);
> > +
> > +MODULE_AUTHOR("Eason Yang <j2anfernee at gmail.com>");
> > +MODULE_DESCRIPTION("Nuvoton NCT720x voltage monitor driver");
> > +MODULE_LICENSE("GPL");
>
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