Re: [PATCH v6 5/5] iio: magnetometer: Add mmc5633 sensor

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Tue, Oct 14, 2025 at 12:40:04PM -0400, Frank Li wrote:
> Add mmc5633 sensor basic support.
> - Support read 20 bits X/Y/Z magnetic.
> - Support I3C HDR mode to send start measurememt command.
> - Support I3C HDR mode to read all sensors data by one command.

...

> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/i3c/device.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/init.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/pm.h>
> +#include <linux/regmap.h>
> +#include <linux/unaligned.h>

Follow IWYU principle, many are missing.

...

> +#define MMC5633_STATUS1_MEAS_T_DONE_BIT	BIT(7)
> +#define MMC5633_STATUS1_MEAS_M_DONE_BIT	BIT(6)

+ bits.h

...

> +#define MMC5633_WAIT_SET_RESET_US	1000

Perhaps (1 * MSEC_PER_USEC) ?

...

> +#define MMC5633_HDR_CTRL0_MEAS_M	0x01
> +#define MMC5633_HDR_CTRL0_MEAS_T	0x03
> +#define MMC5633_HDR_CTRL0_SET		0X05

Keep the style of the values consistent.

> +#define MMC5633_HDR_CTRL0_RESET		0x07

...

> +struct mmc5633_data {
> +	struct device *dev;
> +	struct i3c_device *i3cdev;
> +	struct mutex mutex; /* protect to finish one whole measurement */

+ mutex.h

> +	struct regmap *regmap;
> +};

...

> +static int mmc5633_get_samp_freq_index(struct mmc5633_data *data,
> +				       int val, int val2)
> +{
> +	int i;

Why signed?

> +	for (i = 0; i < ARRAY_SIZE(mmc5633_samp_freq); i++)

+ array_size.h

> +		if (mmc5633_samp_freq[i].val == val &&
> +		    mmc5633_samp_freq[i].val2 == val2)
> +			return i;
> +	return -EINVAL;
> +}

...

> +static int mmc5633_init(struct mmc5633_data *data)
> +{
> +	unsigned int reg_id, ret;

Have you ever compiled this?
Why ret is unsigned?

> +	ret = regmap_read(data->regmap, MMC5633_REG_ID, &reg_id);
> +	if (ret < 0)
> +		return dev_err_probe(data->dev, ret,
> +				     "Error reading product id\n");

+ dev_printk.h

> +	/*
> +	 * Make sure we restore sensor characteristics, by doing
> +	 * a SET/RESET sequence, the axis polarity being naturally
> +	 * aligned after RESET.
> +	 */
> +	ret = regmap_write(data->regmap, MMC5633_REG_CTRL0, MMC5633_CTRL0_SET);
> +	if (ret < 0)
> +		return ret;

> +	fsleep(MMC5633_WAIT_SET_RESET_US);

Do you have a reference to a datasheet? Perhaps add a small comment with it.

> +	ret = regmap_write(data->regmap, MMC5633_REG_CTRL0, MMC5633_CTRL0_RESET);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* set default sampling frequency */
> +	return regmap_update_bits(data->regmap, MMC5633_REG_CTRL1,
> +				  MMC5633_CTRL1_BW_MASK,
> +				  FIELD_PREP(MMC5633_CTRL1_BW_MASK, 0));
> +}

...

> +static int mmc5633_take_measurement(struct mmc5633_data *data, int address)
> +{
> +	unsigned int reg_status;
> +	int ret;
> +	int val;
> +
> +	val = (address == MMC5633_TEMPERATURE) ? MMC5633_CTRL0_MEAS_T : MMC5633_CTRL0_MEAS_M;
> +	ret = regmap_write(data->regmap, MMC5633_REG_CTRL0, val);
> +	if (ret < 0)
> +		return ret;
> +
> +	val = (address == MMC5633_TEMPERATURE) ?
> +	      MMC5633_STATUS1_MEAS_T_DONE_BIT : MMC5633_STATUS1_MEAS_M_DONE_BIT;
> +	ret = regmap_read_poll_timeout(data->regmap, MMC5633_REG_STATUS1, reg_status,
> +				       reg_status & val, 10000, 10000 * 100);

10 * MSEC_PER_USEC, 100 * 10 * MSEC_PER_USEC

> +	if (ret) {
> +		dev_err(data->dev, "data not ready\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}

...

> +static int mmc5633_read_measurement(struct mmc5633_data *data, int address, void *buf, size_t sz)
> +{
> +	u8 data_cmd[2], status[2];
> +	int ret, val, ready;
> +
> +	if (mmc5633_is_support_hdr(data)) {
> +		struct i3c_xfer xfers_wr_cmd[] = {
> +			{
> +				.cmd = 0x3b,
> +				.len = 2,
> +				.data.out = data_cmd,
> +			}
> +		};

> +

Redundant blank line.

> +		struct i3c_xfer xfers_rd_sta_cmd[] = {
> +			{
> +				.cmd = 0x23 | BIT(7), /* RDSTA CMD */
> +				.len = 2,
> +				.data.in = status,
> +			},
> +		};
> +

Ditto.

> +		struct i3c_xfer xfers_rd_data_cmd[] = {
> +			{
> +				.cmd = 0x22 | BIT(7), /* RDLONG CMD */
> +				.len = sz,
> +				.data.in = buf,
> +			},
> +		};
> +
> +		data_cmd[0] = 0;
> +		data_cmd[1] = (address == MMC5633_TEMPERATURE) ?
> +			      MMC5633_HDR_CTRL0_MEAS_T : MMC5633_HDR_CTRL0_MEAS_M;
> +
> +		ret = i3c_device_do_xfers(data->i3cdev, xfers_wr_cmd, 1, I3C_HDR_DDR);
> +		if (ret < 0)
> +			return ret;
> +
> +		ready = (address == MMC5633_TEMPERATURE) ?
> +			MMC5633_STATUS1_MEAS_T_DONE_BIT : MMC5633_STATUS1_MEAS_M_DONE_BIT;
> +		ret = read_poll_timeout(i3c_device_do_xfers, val,
> +					val ||
> +					status[0] & ready,
> +					10000, 10000 * 100, 0,

Use MSEC_PER_USEC as per above.

> +					data->i3cdev, xfers_rd_sta_cmd, 1, I3C_HDR_DDR);

> +

Redundant blank line, and instead...

> +		if (ret || val) {
> +			dev_err(data->dev, "data not ready\n");
> +			return ret ? ret : -EIO;
> +		}

...split this conditional to the linear ones.

> +		return i3c_device_do_xfers(data->i3cdev, xfers_rd_data_cmd, 1, I3C_HDR_DDR);
> +	}
> +
> +	/* Fallback to use SDR/I2C mode */
> +	ret = mmc5633_take_measurement(data, address);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (address == MMC5633_TEMPERATURE)
> +		/*
> +		 * Put tempeature to last byte of buff to align HDR case.
> +		 * I3C will early terminate data read if previous data is not
> +		 * available.
> +		 */
> +		return regmap_bulk_read(data->regmap, MMC5633_REG_TOUT, buf + sz - 1, 1);


> +	return regmap_bulk_read(data->regmap, MMC5633_REG_XOUT_L, buf, sz);
> +}

...

> +#define MMC5633_ALL_SIZE (3 * 3 + 1) /* each channel have 3 byte and TEMP */

have --> has and put comment on top of the definition.

...

> +	char buf[MMC5633_ALL_SIZE];
> +	unsigned int reg;
> +	int ret, i;

Why is 'i' signed?

> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		scoped_guard(mutex, &data->mutex) {

+ cleanup.h

> +			ret = mmc5633_read_measurement(data, chan->address, buf, MMC5633_ALL_SIZE);
> +			if (ret < 0)
> +				return ret;
> +		}
> +
> +		ret = mmc5633_get_raw(data, chan->address, buf, val);
> +		if (ret < 0)
> +			return ret;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		if (chan->type == IIO_MAGN) {
> +			*val = 0;
> +			*val2 = 62500;
> +		} else {
> +			*val = 0;
> +			*val2 = 800000000; /* 0.8C */
> +		}
> +		return IIO_VAL_INT_PLUS_NANO;
> +	case IIO_CHAN_INFO_OFFSET:
> +		if (chan->type == IIO_TEMP) {
> +			*val = -75;
> +			return IIO_VAL_INT;
> +		}
> +		return -EINVAL;
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		scoped_guard(mutex, &data->mutex) {
> +			ret = regmap_read(data->regmap, MMC5633_REG_CTRL1, &reg);
> +			if (ret < 0)
> +				return ret;
> +		}
> +
> +		i = FIELD_GET(MMC5633_CTRL1_BW_MASK, reg);

+ bitfield.h

> +		if (i >= ARRAY_SIZE(mmc5633_samp_freq))
> +			return -EINVAL;
> +
> +		*val = mmc5633_samp_freq[i].val;
> +		*val2 = mmc5633_samp_freq[i].val2;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	default:
> +		return -EINVAL;
> +	}

...

> +static bool mmc5633_is_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case MMC5633_REG_CTRL0:
> +	case MMC5633_REG_CTRL1:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}

+ types.h

...

> +static int mmc5633_common_probe(struct device *dev, struct regmap *regmap,
> +				char *name, struct i3c_device *i3cdev)
> +{
> +	struct mmc5633_data *data;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;

+ errno.h

> +	dev_set_drvdata(dev, indio_dev);

+ device.h

> +	data = iio_priv(indio_dev);
> +
> +	data->regmap = regmap;
> +	data->i3cdev = i3cdev;
> +	data->dev = dev;
> +
> +	ret = devm_mutex_init(dev, &data->mutex);
> +	if (ret)
> +		return ret;
> +
> +	indio_dev->info = &mmc5633_info;
> +	indio_dev->name = name;
> +	indio_dev->channels = mmc5633_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(mmc5633_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = mmc5633_init(data);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "mmc5633 chip init failed\n");
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}

...

> +static DEFINE_SIMPLE_DEV_PM_OPS(mmc5633_pm_ops, mmc5633_suspend,
> +				mmc5633_resume);

One line (despite of being longer than 80).

...

> +static const struct of_device_id mmc5633_of_match[] = {
> +	{ .compatible = "memsic,mmc5603", },
> +	{ .compatible = "memsic,mmc5633", },

Remove inner commas.

> +	{ }
> +};

...

> +static int mmc5633_i3c_probe(struct i3c_device *i3cdev)
> +{
> +	struct device *dev = i3cdev_to_dev(i3cdev);
> +	struct regmap *regmap;
> +
> +	regmap = devm_regmap_init_i3c(i3cdev, &mmc5633_regmap_config);
> +	if (IS_ERR(regmap))

+ err.h

> +		return dev_err_probe(dev, PTR_ERR(regmap),
> +				     "Failed to register i3c regmap\n");
> +
> +	return mmc5633_common_probe(dev, regmap, "mmc5633_i3c", i3cdev);
> +}

...

> +static struct i3c_driver mmc5633_i3c_driver = {
> +	.driver = {
> +		.name = "mmc5633_i3c",
> +	},
> +	.probe = mmc5633_i3c_probe,
> +	.id_table = mmc5633_i3c_ids,
> +};

> +

Redundant blank line.

> +module_i3c_i2c_driver(mmc5633_i3c_driver, &mmc5633_i2c_driver)

-- 
With Best Regards,
Andy Shevchenko