On Wed, Nov 06, 2024 at 10:39:16AM +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 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.
...
> + * Copyright (c) 2022 Nuvoton Inc.
2024?
...
+ array_size.h
+ bits.h
> +#include <linux/delay.h>
> +#include <linux/device.h>
+ err.h
> +#include <linux/i2c.h>
> +#include <linux/iio/events.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
Move these to be a separate group...
> +#include <linux/init.h>
+ mod_devicetable.h
> +#include <linux/module.h>
> +#include <linux/mutex.h>
+ types.h
...somewhere here after a blank line.
...
> +static const u8 REG_VIN[VIN_MAX] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05,
> + 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B};
Better to have it done like this
static const u8 REG_VIN[VIN_MAX] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0 - 7 */
0x08, 0x09, 0x0A, 0x0B, /* 8 - 11 */
};
Note the following: the values are placed on separate lines with trailing
commas on each line and with grouping by powwer-of-2 per line.
> +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[] = {
> + 0, /* Not used */
> + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
> +};
Ditto for the above initialisers.
> +
> +
One blank line is enough.
> +/* List of supported devices */
> +enum nct720x_chips {
> + nct7201, nct7202
Leave trailing comma.
> +};
...
> +/* Read 1-byte register. Returns unsigned byte data or -ERRNO on error. */
> +static int nct720x_read_reg(struct nct720x_chip_info *chip, u8 reg)
> +{
> + struct i2c_client *client = chip->client;
> +
> + return i2c_smbus_read_byte_data(client, reg);
> +}
> +
> +/* Read 1-byte register. Returns unsigned word data or -ERRNO on error. */
> +static int nct720x_read_word_swapped_reg(struct nct720x_chip_info *chip, u8 reg)
> +{
> + struct i2c_client *client = chip->client;
> +
> + return i2c_smbus_read_word_swapped(client, reg);
> +}
> +
> +/*
> + * Read 2-byte register. Returns register in big-endian format or
> + * -ERRNO on error.
> + */
> +static int nct720x_read_reg16(struct nct720x_chip_info *chip, u8 reg)
> +{
> + struct i2c_client *client = chip->client;
> + int ret, low;
> + mutex_lock(&chip->access_lock);
If you are going with this, use cleanup.h.
> + ret = i2c_smbus_read_byte_data(client, reg);
> + if (ret >= 0) {
> + low = ret;
> + ret = i2c_smbus_read_byte_data(client, reg + 1);
> + if (ret >= 0)
> + ret = low | (ret << 8);
Hmm... Does it require to have two separate transactions? In case of regmap,
can't bulk transfer be performed for that?
> + }
> +
> + mutex_unlock(&chip->access_lock);
> + return ret;
> +}
I have no explanations why regmap I2C can't be used.
...
> +/* Write 1-byte register. Returns 0 or -ERRNO on error. */
> +static int nct720x_write_reg(struct nct720x_chip_info *chip, u8 reg, u8 val)
> +{
> + struct i2c_client *client = chip->client;
> + int err;
> +
> + err = i2c_smbus_write_byte_data(client, reg, val);
> + /* wait for write command to be finished */
Is there any justification for the chosen value (I mean datasheet
recommendations or so)?
> + mdelay(10);
> +
> + return err;
> +}
...
> +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];
> + int v1, v2, volt, err;
> + struct nct720x_chip_info *chip = iio_priv(indio_dev);
> +
> + if (chan->type != IIO_VOLTAGE)
> + return -EOPNOTSUPP;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_PROCESSED:
> + mutex_lock(&chip->access_lock);
> + if (chip->use_read_byte_vin) {
> + /*
> + * MNTVIN Low Byte together with MNTVIN High Byte
> + * forms the 13-bit count value. If MNTVIN High
> + * Byte readout is read successively, the
> + * NCT7201/NCT7202 will latch the MNTVIN Low Byte
> + * for next read.
> + */
> + v1 = nct720x_read_reg(chip, REG_VIN[index]);
> + if (v1 < 0) {
> + err = v1;
> + goto abort;
> + }
> +
> + v2 = nct720x_read_reg(chip, REG_VOLT_LOW_BYTE);
> + if (v2 < 0) {
> + err = v2;
> + goto abort;
> + }
> + volt = (v1 << 8) | v2; /* Convert back to 16-bit value */
Hmm... I would expect volt to be __be16, but since you have two separate reads
it's probably fine.
> + } else {
> + /* NCT7201/NCT7202 also supports read word-size data */
> + volt = nct720x_read_word_swapped_reg(chip, REG_VIN[index]);
> + }
> +
> + /* Voltage(V) = 13bitCountValue * 0.0004995 */
> + volt = (volt >> 3) * NCT720X_IN_SCALING;
> + *val = volt / 10000;
> + mutex_unlock(&chip->access_lock);
> + return IIO_VAL_INT;
> + default:
> + return -EINVAL;
> + }
> +abort:
> + mutex_unlock(&chip->access_lock);
> + return err;
Yeah, this will gone with cleanup.h in use.
Ditto for all other places like this.
> +}
...
> +{
> + struct nct720x_chip_info *chip = iio_priv(indio_dev);
> + int index, err = 0;
> + long v1, v2, volt;
Why long? Wouldn't int / unsigned int suffice for v1 / v2?
> +
> + index = nct720x_chan_to_index[chan->address];
> + volt = (val * 10000) / NCT720X_IN_SCALING;
Please, use named constant for 10000 as you used it at least twice in the code.
> + v1 = volt >> 5;
> + v2 = (volt & 0x1f) << 3;
In the similar way it seems like some endianess and bit width manipulations.
Can v be an array of u8:s which you just fill with put_unaligned_be16() or so?
> + if (chan->type != IIO_VOLTAGE)
> + return -EOPNOTSUPP;
> +
> + if (info == IIO_EV_INFO_VALUE) {
> + if (dir == IIO_EV_DIR_FALLING) {
> + mutex_lock(&chip->access_lock);
> + err = nct720x_write_reg(chip, REG_VIN_LOW_LIMIT[index], v1);
> + if (err < 0) {
> + pr_err("Failed to write REG_VIN%d_LOW_LIMIT\n", index + 1);
> + goto abort;
> + }
> +
> + err = nct720x_write_reg(chip, REG_VIN_LOW_LIMIT_LSB[index], v2);
> + if (err < 0) {
> + pr_err("Failed to write REG_VIN%d_LOW_LIMIT_LSB\n", index + 1);
> + goto abort;
> + }
> + } else {
> + mutex_lock(&chip->access_lock);
> + err = nct720x_write_reg(chip, REG_VIN_HIGH_LIMIT[index], v1);
> + if (err < 0) {
> + pr_err("Failed to write REG_VIN%d_HIGH_LIMIT\n", index + 1);
> + goto abort;
> + }
> +
> + err = nct720x_write_reg(chip, REG_VIN_HIGH_LIMIT_LSB[index], v2);
> + if (err < 0) {
> + pr_err("Failed to write REG_VIN%d_HIGH_LIMIT_LSB\n", index + 1);
> + goto abort;
> + }
> + }
> + }
> +abort:
> + mutex_unlock(&chip->access_lock);
> + return err;
> +}
...
> + strscpy(info->type, "nct720x", I2C_NAME_SIZE);
Use 2-argument strscpy().
...
> +static const struct i2c_device_id nct720x_id[];
Remove this. It's not needed.
...
> +static int nct720x_init_chip(struct nct720x_chip_info *chip)
> +{
> + int value = 0;
Why signed?
> + int err = 0;
Redundant assignments.
> + /* Initial reset */
> + err = nct720x_write_reg(chip, REG_CONFIGURATION, CONFIGURATION_INIT);
> + if (err) {
> + pr_err("Failed to write REG_CONFIGURATION\n");
> + return err;
> + }
> +
> + /* Enable Channel */
> + err = nct720x_write_reg(chip, REG_CHANNEL_ENABLE_1, 0xff);
Magic 0xff.
Should be GENMASK() ? Anything else?
> + if (err) {
> + pr_err("Failed to write REG_CHANNEL_ENABLE_1\n");
> + return err;
> + }
> +
> + if (chip->type == nct7202) {
> + err = nct720x_write_reg(chip, REG_CHANNEL_ENABLE_2, 0xf);
Ditto.
> + if (err) {
> + pr_err("Failed to write REG_CHANNEL_ENABLE_2\n");
> + return err;
> + }
> + }
> +
> + value = nct720x_read_reg16(chip, REG_CHANNEL_ENABLE_1);
> + if (value < 0)
> + return value;
> + chip->vin_mask = value;
> +
> + /* Start monitoring if needed */
> + value = nct720x_read_reg(chip, REG_CONFIGURATION);
> + if (value < 0) {
> + pr_err("Failed to read REG_CONFIGURATION\n");
> + return value;
> + }
> +
> + value |= CONFIGURATION_START;
> + err = nct720x_write_reg(chip, REG_CONFIGURATION, value);
> + if (err < 0) {
> + pr_err("Failed to write REG_CONFIGURATION\n");
> + return err;
> + }
> +
> + return 0;
> +}
...
> + ret = of_property_read_u32(client->dev.of_node, "read-vin-data-size", &tmp);
No OF-centric APIs in a new code, please.
Use device_property_read_u32() and include property.h for that.
> + if (ret < 0) {
> + pr_err("read-vin-data-size property not found\n");
> + return ret;
> + }
...
> + mutex_init(&chip->access_lock);
ret = devm_mutex_init(...);
...
> + /* this is only used for device removal purposes */
> + i2c_set_clientdata(client, indio_dev);
Will be gone after removing ->remove().
...
> + iio_device_register(indio_dev);
No error checks? In any case devm_ variant especially needs this.
> + return 0;
return devm_iio_device_register(...);
...
> +static const struct i2c_device_id nct720x_id[] = {
> + { "nct7201", nct7201 },
> + { "nct7202", nct7202 },
Please, use chip_info custom data structure instead of enum values.
> + {}
> +};
> +MODULE_DEVICE_TABLE(i2c, nct720x_id);
> +
> +static const struct of_device_id nct720x_of_match[] = {
> + {
> + .compatible = "nuvoton,nct7201",
> + .data = (void *)nct7201
> + },
> + {
> + .compatible = "nuvoton,nct7202",
> + .data = (void *)nct7202
As per above and leave trailing commas.
> + },
> + { },
Drop trailing comma in the terminator entries.
> +};
> +
Redundant blank line.
> +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,
> + .remove = nct720x_remove,
> + .id_table = nct720x_id,
> + .detect = nct720x_detect,
> + .address_list = nct720x_address_list,
> +};
> +
Redundant blank line.
> +module_i2c_driver(nct720x_driver);
--
With Best Regards,
Andy Shevchenko
