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iio: magnetometer: add driver for MEMSIC MMC5983MA

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Add support for the MEMSIC MMC5983MA 3-axis magnetometer. The driver
provides raw magnetic field readings via IIO sysfs with SET/RESET
offset cancellation for each measurement.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Vladislav Kulikov <vlad.kulikov.c@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Vladislav Kulikov 2026-05-11 19:11:35 +00:00 committed by Jonathan Cameron
parent ecedfa46a2
commit 243a738ccd
4 changed files with 361 additions and 0 deletions
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1
MAINTAINERS
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@ -17184,6 +17184,7 @@ M: Vladislav Kulikov <vlad.kulikov.c@gmail.com>
L: linux-iio@vger.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/iio/magnetometer/memsic,mmc5983.yaml
F: drivers/iio/magnetometer/mmc5983.c
MEN A21 WATCHDOG DRIVER
M: Johannes Thumshirn <morbidrsa@gmail.com>

11
drivers/iio/magnetometer/Kconfig
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@ -151,6 +151,17 @@ config MMC5633
To compile this driver as a module, choose M here: the module
will be called mmc5633
config MMC5983
tristate "MEMSIC MMC5983 3-axis magnetic sensor"
depends on I2C
select REGMAP_I2C
help
Say yes here to build support for the MEMSIC MMC5983 3-axis
magnetic sensor.
To compile this driver as a module, choose M here: the module
will be called mmc5983
config IIO_ST_MAGN_3AXIS
tristate "STMicroelectronics magnetometers 3-Axis Driver"
depends on (I2C || SPI_MASTER) && SYSFS

1
drivers/iio/magnetometer/Makefile
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@ -16,6 +16,7 @@ obj-$(CONFIG_MAG3110) += mag3110.o
obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
obj-$(CONFIG_MMC35240) += mmc35240.o
obj-$(CONFIG_MMC5633) += mmc5633.o
obj-$(CONFIG_MMC5983) += mmc5983.o
obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o
st_magn-y := st_magn_core.o

348
drivers/iio/magnetometer/mmc5983.c Normal file
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@ -0,0 +1,348 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* MMC5983 - MEMSIC 3-axis Magnetic Sensor
*
* Copyright (c) 2026, Vlad Kulikov <vlad.kulikov.c@gmail.com>
*
* IIO driver for MMC5983
*/
#include <linux/array_size.h>
#include <linux/bits.h>
#include <linux/cleanup.h>
#include <linux/delay.h>
#include <linux/dev_printk.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#include <linux/time.h>
#include <linux/types.h>
#define MMC5983_REG_XOUT0 0x00
#define MMC5983_REG_XOUT1 0x01
#define MMC5983_REG_YOUT0 0x02
#define MMC5983_REG_YOUT1 0x03
#define MMC5983_REG_ZOUT0 0x04
#define MMC5983_REG_ZOUT1 0x05
#define MMC5983_REG_XYZOUT2 0x06
#define MMC5983_REG_STATUS 0x08
#define MMC5983_REG_CTRL0 0x09
#define MMC5983_REG_CTRL1 0x0A
#define MMC5983_REG_CTRL2 0x0B
#define MMC5983_REG_CTRL3 0x0C
#define MMC5983_REG_ID 0x2F
#define MMC5983_PRODUCT_ID 0x30
#define MMC5983_STATUS_MEAS_M_DONE_BIT BIT(0)
#define MMC5983_STATUS_OTP_RD_DONE_BIT BIT(4)
#define MMC5983_CTRL0_TM_M_BIT BIT(0)
#define MMC5983_CTRL0_SET_BIT BIT(3)
#define MMC5983_CTRL0_RESET_BIT BIT(4)
#define MMC5983_CTRL0_OTP_RD_BIT BIT(6)
#define MMC5983_CTRL1_SW_RST_BIT BIT(7)
enum mmc5983_axis {
MMC5983_AXIS_X,
MMC5983_AXIS_Y,
MMC5983_AXIS_Z,
};
struct mmc5983_data {
struct regmap *regmap;
/* Protects chip access during SET/RESET measurement sequence */
struct mutex mutex;
};
#define MMC5983_CHANNEL(_axis) { \
.type = IIO_MAGN, \
.modified = 1, \
.channel2 = IIO_MOD_##_axis, \
.address = MMC5983_AXIS_##_axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
}
static const struct iio_chan_spec mmc5983_channels[] = {
MMC5983_CHANNEL(X),
MMC5983_CHANNEL(Y),
MMC5983_CHANNEL(Z),
};
static int mmc5983_pulse_coil(struct mmc5983_data *data, unsigned int coil_bit)
{
int ret;
ret = regmap_write(data->regmap, MMC5983_REG_CTRL0, coil_bit);
if (ret)
return ret;
/*
* Datasheet page 15: SET/RESET coil pulse is 500 ns.
* Vendor sample code waits 500 us before the next operation.
*/
fsleep(500);
return 0;
}
static int mmc5983_take_measurement(struct mmc5983_data *data, int m[3])
{
unsigned int status;
u8 buf[7];
int ret;
ret = regmap_write(data->regmap, MMC5983_REG_CTRL0,
MMC5983_CTRL0_TM_M_BIT);
if (ret)
return ret;
/*
* Datasheet page 15: measurement time is 8 ms at BW=00 (default,
* slowest setting). Use a 50 ms timeout for margin.
*/
ret = regmap_read_poll_timeout(data->regmap, MMC5983_REG_STATUS,
status,
status & MMC5983_STATUS_MEAS_M_DONE_BIT,
10 * USEC_PER_MSEC,
50 * USEC_PER_MSEC);
if (ret)
return ret;
ret = regmap_bulk_read(data->regmap, MMC5983_REG_XOUT0, buf,
sizeof(buf));
if (ret)
return ret;
m[0] = (buf[0] << 10) | (buf[1] << 2) | ((buf[6] >> 6) & 0x3);
m[1] = (buf[2] << 10) | (buf[3] << 2) | ((buf[6] >> 4) & 0x3);
m[2] = (buf[4] << 10) | (buf[5] << 2) | ((buf[6] >> 2) & 0x3);
return 0;
}
static int mmc5983_read_raw(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, int *val,
int *val2, long mask)
{
struct mmc5983_data *data = iio_priv(indio_dev);
int m1[3], m2[3];
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW: {
guard(mutex)(&data->mutex);
/* SET: magnetize sensor elements in forward direction */
ret = mmc5983_pulse_coil(data, MMC5983_CTRL0_SET_BIT);
if (ret)
return ret;
ret = mmc5983_take_measurement(data, m1);
if (ret)
return ret;
/* RESET: magnetize sensor elements in reverse direction */
ret = mmc5983_pulse_coil(data, MMC5983_CTRL0_RESET_BIT);
if (ret)
return ret;
ret = mmc5983_take_measurement(data, m2);
if (ret)
return ret;
*val = (m1[chan->address] - m2[chan->address]) / 2;
return IIO_VAL_INT;
}
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = 61035;
return IIO_VAL_INT_PLUS_NANO;
default:
return -EINVAL;
}
}
static const struct iio_info mmc5983_info = {
.read_raw = mmc5983_read_raw,
};
static bool mmc5983_is_writeable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MMC5983_REG_CTRL0:
case MMC5983_REG_CTRL1:
case MMC5983_REG_CTRL2:
case MMC5983_REG_CTRL3:
return true;
default:
return false;
}
}
static bool mmc5983_is_readable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MMC5983_REG_XOUT0:
case MMC5983_REG_XOUT1:
case MMC5983_REG_YOUT0:
case MMC5983_REG_YOUT1:
case MMC5983_REG_ZOUT0:
case MMC5983_REG_ZOUT1:
case MMC5983_REG_XYZOUT2:
case MMC5983_REG_STATUS:
case MMC5983_REG_CTRL0:
case MMC5983_REG_CTRL1:
case MMC5983_REG_CTRL2:
case MMC5983_REG_CTRL3:
case MMC5983_REG_ID:
return true;
default:
return false;
}
}
static bool mmc5983_is_volatile_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MMC5983_REG_XOUT0:
case MMC5983_REG_XOUT1:
case MMC5983_REG_YOUT0:
case MMC5983_REG_YOUT1:
case MMC5983_REG_ZOUT0:
case MMC5983_REG_ZOUT1:
case MMC5983_REG_XYZOUT2:
case MMC5983_REG_STATUS:
case MMC5983_REG_CTRL0:
case MMC5983_REG_CTRL1:
return true;
default:
return false;
}
}
static const struct regmap_config mmc5983_regmap_config = {
.name = "mmc5983_regmap",
.reg_bits = 8,
.val_bits = 8,
.max_register = MMC5983_REG_ID,
.writeable_reg = mmc5983_is_writeable_reg,
.readable_reg = mmc5983_is_readable_reg,
.volatile_reg = mmc5983_is_volatile_reg,
};
static int mmc5983_init(struct mmc5983_data *data)
{
struct regmap *regmap = data->regmap;
struct device *dev = regmap_get_device(regmap);
unsigned int reg_id, status;
int ret;
ret = regmap_read(regmap, MMC5983_REG_ID, &reg_id);
if (ret)
return dev_err_probe(dev, ret, "Error reading product id\n");
if (reg_id != MMC5983_PRODUCT_ID)
dev_info(dev, "unexpected product id 0x%02x\n", reg_id);
ret = regmap_write(regmap, MMC5983_REG_CTRL1, MMC5983_CTRL1_SW_RST_BIT);
if (ret)
return ret;
/* Datasheet page 15: power-on time after SW_RST is 10 ms */
fsleep(10 * USEC_PER_MSEC);
ret = regmap_write(regmap, MMC5983_REG_CTRL0, MMC5983_CTRL0_OTP_RD_BIT);
if (ret)
return ret;
/*
* Datasheet page 15: OTP read completes and self-clears. No separate
* OTP refresh timeout is specified, so use the 10 ms power-on time as
* a conservative upper bound.
*/
ret = regmap_read_poll_timeout(regmap, MMC5983_REG_STATUS, status,
status & MMC5983_STATUS_OTP_RD_DONE_BIT,
USEC_PER_MSEC,
10 * USEC_PER_MSEC);
if (ret)
return ret;
/* SET: magnetize sensor elements in forward direction */
ret = mmc5983_pulse_coil(data, MMC5983_CTRL0_SET_BIT);
if (ret)
return ret;
/* RESET: magnetize sensor elements in reverse direction */
return mmc5983_pulse_coil(data, MMC5983_CTRL0_RESET_BIT);
}
static int mmc5983_probe(struct i2c_client *i2c)
{
struct device *dev = &i2c->dev;
struct mmc5983_data *data;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
ret = devm_mutex_init(dev, &data->mutex);
if (ret)
return ret;
data->regmap = devm_regmap_init_i2c(i2c, &mmc5983_regmap_config);
if (IS_ERR(data->regmap))
return dev_err_probe(dev, PTR_ERR(data->regmap),
"failed to allocate register map\n");
indio_dev->info = &mmc5983_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->name = "mmc5983";
indio_dev->channels = mmc5983_channels;
indio_dev->num_channels = ARRAY_SIZE(mmc5983_channels);
ret = mmc5983_init(data);
if (ret)
return dev_err_probe(dev, ret, "mmc5983 chip init failed\n");
return devm_iio_device_register(dev, indio_dev);
}
static const struct of_device_id mmc5983_of_match[] = {
{ .compatible = "memsic,mmc5983" },
{ }
};
MODULE_DEVICE_TABLE(of, mmc5983_of_match);
static const struct i2c_device_id mmc5983_id[] = {
{ "mmc5983" },
{ }
};
MODULE_DEVICE_TABLE(i2c, mmc5983_id);
static struct i2c_driver mmc5983_driver = {
.driver = {
.name = "mmc5983",
.of_match_table = mmc5983_of_match,
},
.probe = mmc5983_probe,
.id_table = mmc5983_id,
};
module_i2c_driver(mmc5983_driver);
MODULE_AUTHOR("Vladislav Kulikov <vlad.kulikov.c@gmail.com>");
MODULE_DESCRIPTION("MEMSIC MMC5983 magnetic sensor driver");
MODULE_LICENSE("GPL");