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[89.139.15.25]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4548e6a5b65sm28541785f8f.8.2026.05.11.12.11.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 May 2026 12:11:51 -0700 (PDT) From: Vladislav Kulikov To: jic23@kernel.org, krzk+dt@kernel.org, robh@kernel.org, conor+dt@kernel.org Cc: dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, andriy.shevchenko@intel.com, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Vladislav Kulikov Subject: [PATCH v3 2/2] iio: magnetometer: add driver for MEMSIC MMC5983MA Date: Mon, 11 May 2026 19:11:35 +0000 Message-ID: <20260511191135.36691-3-vlad.kulikov.c@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260511191135.36691-1-vlad.kulikov.c@gmail.com> References: <20260511191135.36691-1-vlad.kulikov.c@gmail.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Vladislav Kulikov --- MAINTAINERS | 1 + drivers/iio/magnetometer/Kconfig | 11 + drivers/iio/magnetometer/Makefile | 1 + drivers/iio/magnetometer/mmc5983.c | 345 +++++++++++++++++++++++++++++ 4 files changed, 358 insertions(+) create mode 100644 drivers/iio/magnetometer/mmc5983.c diff --git a/MAINTAINERS b/MAINTAINERS index 952fbf3020a4..b1d9d7b586a1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17175,6 +17175,7 @@ M: Vladislav Kulikov 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 diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig index fb313e591e85..ea2697fb5ab6 100644 --- a/drivers/iio/magnetometer/Kconfig +++ b/drivers/iio/magnetometer/Kconfig @@ -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 diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile index 5bd227f8c120..7fd9b3fd914e 100644 --- a/drivers/iio/magnetometer/Makefile +++ b/drivers/iio/magnetometer/Makefile @@ -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 diff --git a/drivers/iio/magnetometer/mmc5983.c b/drivers/iio/magnetometer/mmc5983.c new file mode 100644 index 000000000000..400406c824d7 --- /dev/null +++ b/drivers/iio/magnetometer/mmc5983.c @@ -0,0 +1,345 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * MMC5983 - MEMSIC 3-axis Magnetic Sensor + * + * Copyright (c) 2026, Vlad Kulikov + * + * IIO driver for MMC5983 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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, ®_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 "); +MODULE_DESCRIPTION("MEMSIC MMC5983 magnetic sensor driver"); +MODULE_LICENSE("GPL"); -- 2.43.0