Add devicetree bindings for the Melexis MLX90393
3-axis magnetometer and temperature sensor.

The device supports magnetic field and temperature measurements over I2C and SPI interfaces.

This initial binding documents the I2C interface.

Signed-off-by Nikhil Gautam <[email protected]>

---
 .../iio/magnetometer/melexis,mlx90393.yaml    | 54 +++++++++++++++++++
 MAINTAINERS                                   |  6 +++
 2 files changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/melexis,mlx90393.yaml

Add devicetree bindings for the Melexis MLX90393
3-axis magnetometer and temperature sensor.

The device supports magnetic field and temperature measurements over I2C and SPI interfaces.

This initial binding documents the I2C interface.

Signed-off-by Nikhil Gautam <[email protected]>

---
 .../iio/magnetometer/melexis,mlx90393.yaml    | 54 +++++++++++++++++++
 MAINTAINERS                                   |  6 +++
 2 files changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/melexis,mlx90393.yaml

Documentation/devicetree/bindings/iio/magnetometer/melexis,mlx90393.yaml new file +22 -0

new file mode 100644
index 000000000000..33ab0be66345
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/magnetometer/melexis,mlx90393.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Melexis MLX90393 magnetometer sensor
+
+maintainers:
+  - Nikhil Gautam <[email protected]>
+
+description:
+  Melexis MLX90393 3-axis magnetometer and temperature sensor.
+
+properties:
+  compatible:
+    const: melexis,mlx90393
+
+  reg:
+    maxItems: 1
+
+  interrupts:

Documentation/devicetree/bindings/iio/magnetometer/melexis,mlx90393.yaml new file +22 -0

+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        magnetometer@c {
+            compatible = "melexis,mlx90393";
+            reg = <0x0c>;
+
+            interrupt-parent = <&gpio>;
+            interrupts = <17 IRQ_TYPE_EDGE_RISING>;
+
+            trigger-gpios = <&gpio 18 GPIO_ACTIVE_HIGH>;
+        };
+    };

MAINTAINERS +6 -0

index a92290fffa16..469ae3f9aa0f 100644
@@ -15501,6 +15501,12 @@ F:	Documentation/scsi/megaraid.rst
 F:	drivers/scsi/megaraid.*
 F:	drivers/scsi/megaraid/
 
+MELEXIS MLX90393 MAGNETOMETER DRIVER
+M:	Nikhil Gautam <[email protected]>
+L:	[email protected]
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/magnetometer/melexis,mlx90393.yaml
+
 MELEXIS MLX90614 DRIVER
 M:	Crt Mori <[email protected]>
 L:	[email protected]

Add Industrial I/O subsystem support for the Melexis MLX90393 3-axis magnetometer and temperature sensor.

The driver currently supports:

raw magnetic field measurements
raw temperature measurements
configurable gain/scale selection
configurable oversampling ratio
direct mode operation

The MLX90393 supports both I2C and SPI interfaces. This initial implementation adds support for the I2C interface.

The device uses a command-based communication protocol rather than a conventional register-addressed interface. A small transport abstraction layer is therefore used instead of regmap to share the common sensor logic between the current I2C implementation and future SPI support without duplicating code.

+ * Datasheet: https://media.melexis.com/-/media/files/documents/datasheets/mlx90393-datasheet-melexis.pdf

drivers/iio/magnetometer/mlx90393_core.c new file +2 -0

+#include <linux/unaligned.h>
+#include <linux/units.h>

drivers/iio/magnetometer/mlx90393_core.c new file +12 -0

+	void *bus_context;
+	const struct mlx90393_transfer_ops *ops;
+	u8 gain_sel;
+	u8 hallconf;
+
+	u8 res_xy;
+	u8 res_z;
+
+	u8 dig_filt;
+	u8 osr;
+	u8 osr2;
+};

drivers/iio/magnetometer/mlx90393_core.c new file +12 -0

+	/* XY axis */
+	{
+		{ 751, 1502, 3004, 6009},
+		{ 601, 1202, 2403, 4840},
+		{ 451, 901, 1803, 3605},
+		{ 376, 751, 1502, 3004},
+		{ 300, 601, 1202, 2403},
+		{ 250, 501, 1001, 2003},
+		{ 200, 401, 801, 1602},
+		{ 150, 300, 601, 1202},
+	},
+	/* Z axis */

+};

drivers/iio/magnetometer/mlx90393_core.c new file +6 -0

+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),\
+	.info_mask_separate_available = \
+		BIT(IIO_CHAN_INFO_SCALE),  \
+	.info_mask_shared_by_type_available = \
+		BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
+}

+ * Datasheet: Table 8, Page no. 12

+static int mlx90393_get_tconv_us(struct mlx90393_data *data)

drivers/iio/magnetometer/mlx90393_core.c new file +17 -0

+	int m = 3; /* X,Y,Z */
+
+	/*
+	 * TCONVM = 67 + 64 * 2^OSR * (2 + 2^DIG_FILT)
+	 */
+	tconvm = 67 + (64 * BIT(osr) * (2 + BIT(df)));
+
+	/*
+	 * TCONVT = 67 + 192 * 2^OSR2
+	 */
+	tconvt = 67 + (192 * BIT(osr2));
+	/*
+	 * Total conversion time:
+	 * TSTBY + TACTIVE + m * TCONVM + TCONVT + TCONV_END
+	 */
+	return 220 + 360 + (m * tconvm) + tconvt + 120;
+}

drivers/iio/magnetometer/mlx90393_core.c new file +3 -0

+{
+	return data->ops->xfer(data->bus_context, tx, tx_len, rx, rx_len);
+}

(quoted diff) +2 -0

+	return mlx90393_write_reg(data, reg, reg_val);
+}

drivers/iio/magnetometer/mlx90393_core.c new file +1 -0

+	fsleep(mlx90393_get_tconv_us(data));

drivers/iio/magnetometer/mlx90393_core.c new file +8 -0

+		if (mlx90393_scale_table[axis][i][res] == val2) {
+			*gain = i;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
 

drivers/iio/magnetometer/mlx90393_core.c new file +12 -0

+	ret = mlx90393_find_scale(data, z_axis, val, val2, &gain);
+	if (ret)
+		return ret;
+
+	ret = mlx90393_update_bits(data, MLX90393_REG_CONF1, MLX90393_CONF1_GAIN_SEL,
+				   gain);
+	if (ret)
+		return ret;
+
+	data->gain_sel = gain;
+	return 0;
+}

drivers/iio/magnetometer/mlx90393_core.c new file +8 -0

+		if (mlx90393_osr_avail[i] == val) {
+			*osr = i;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}

drivers/iio/magnetometer/mlx90393_core.c new file +4 -0

+static int mlx90393_set_osr(struct mlx90393_data *data, int val)
+{
+	int osr;
+	int ret;

drivers/iio/magnetometer/mlx90393_core.c new file +6 -0

+	if (ret)
+		return ret;
+
+	data->osr = osr;
+	return 0;
+}

drivers/iio/magnetometer/mlx90393_core.c new file +7 -0

+	if (ret)
+		return ret;
+
+	data->osr2 = val;
+
+	return 0;
+}

drivers/iio/magnetometer/mlx90393_core.c new file +4 -0

+static int mlx90393_write_raw(struct iio_dev *indio_dev,
+			      const struct iio_chan_spec *chan,
+			      int val, int val2,
+			      long mask)

drivers/iio/magnetometer/mlx90393_core.c new file +17 -0

+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO: {
+		guard(mutex)(&data->lock);
+		switch (chan->type) {
+		case IIO_TEMP:
+			return mlx90393_set_temp_osr2(data, val);
+
+		case IIO_MAGN:
+			return mlx90393_set_osr(data, val);
+
+		default:
+			return -EINVAL;
+		}
+	}
+	default:
+		return -EINVAL;
+	}
+}

drivers/iio/magnetometer/mlx90393_core.c new file +7 -0

+static int mlx90393_read_raw(struct iio_dev *indio_dev,
+			     const struct iio_chan_spec *chan,
+			     int *val, int *val2, long mask)
+{
+	struct mlx90393_data *data = iio_priv(indio_dev);
+	int ret;
+

drivers/iio/magnetometer/mlx90393_core.c new file +14 -0

+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_MAGN:
+			return mlx90393_get_scale(data, chan, val, val2);
+
+		case IIO_TEMP:
+			/*
+			 * Datasheet Table 7: Thermal Specification
+			 */
+			*val = 0;
+			*val2 = 22124;
+			return IIO_VAL_INT_PLUS_MICRO;
+
+		default:

+

drivers/iio/magnetometer/mlx90393_core.c new file +16 -0

+		*val = -45114;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		switch (chan->type) {
+		case IIO_TEMP:
+			return mlx90393_get_temp_osr2(data, val);
+		case IIO_MAGN:
+			return mlx90393_get_osr(data, val);
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}

drivers/iio/magnetometer/mlx90393_core.c new file +7 -0

+static int mlx90393_read_avail(struct iio_dev *indio_dev,
+			       const struct iio_chan_spec *chan,
+			       const int **vals,
+			       int *type,
+			       int *length,
+			       long mask)
+{

drivers/iio/magnetometer/mlx90393_core.c new file +28 -0

+		for (unsigned int i = 0; i < MLX90393_GAIN_MAX; i++) {
+			scale_avail[i][0] = 0;
+			scale_avail[i][1] =
+				mlx90393_scale_table[axis][i][res];
+		}
+
+		*vals = &scale_avail[0][0];
+		*type = IIO_VAL_INT_PLUS_NANO;
+		*length = MLX90393_GAIN_MAX * MLX90393_AXIS_MAX;
+		return IIO_AVAIL_LIST;
+	}
+
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		if (chan->type == IIO_TEMP) {
+			*vals = mlx90393_osr2_avail;
+			*type = IIO_VAL_INT;
+			*length = MLX90393_OSR2_MAX;
+		} else {
+			*vals = mlx90393_osr_avail;
+			*type = IIO_VAL_INT;
+			*length = MLX90393_OSR_MAX;
+		}
+		return IIO_AVAIL_LIST;
+
+	default:
+		return -EINVAL;
+	}
+}

drivers/iio/magnetometer/mlx90393_core.c new file +16 -0

+static int mlx90393_init(struct mlx90393_data *data)
+{
+	int ret;
+	u16 reg;
+
+	/* Exit mode */
+	ret = mlx90393_write_cmd(data, MLX90393_CMD_EX);
+	if (ret)
+		return ret;
+
+	/*
+	 * Datasheet section 15.4.1.2 (RT command), Figure 16:
+	 * Wait 1 ms after EX command before issuing RT.
+	 */
+	fsleep(1 * USEC_PER_MSEC);
+

drivers/iio/magnetometer/mlx90393_core.c new file +20 -0

+
+	ret = mlx90393_read_reg(data, MLX90393_REG_CONF1, &reg);
+	if (ret)
+		return ret;
+
+	data->gain_sel = FIELD_GET(MLX90393_CONF1_GAIN_SEL, reg);
+	data->hallconf = FIELD_GET(MLX90393_CONF1_HALLCONF, reg);
+
+	ret = mlx90393_read_reg(data, MLX90393_REG_CONF3, &reg);
+	if (ret)
+		return ret;
+
+	data->res_xy = FIELD_GET(MLX90393_CONF3_RES_X, reg);
+	data->res_z = FIELD_GET(MLX90393_CONF3_RES_Z, reg);
+	data->dig_filt = FIELD_GET(MLX90393_CONF3_DIG_FILT, reg);
+	data->osr = FIELD_GET(MLX90393_CONF3_OSR, reg);
+	data->osr2 = FIELD_GET(MLX90393_CONF3_OSR2, reg);
+
+	return 0;
+}

drivers/iio/magnetometer/mlx90393_i2c.c new file +12 -0

+		[0] = {
+			.addr = client->addr,
+			.len = tx_len,
+			.buf = (u8 *)tx,
+		},
+		[1] = {
+			.addr = client->addr,
+			.flags = I2C_M_RD,
+			.len = rx_len,
+			.buf = rx,
+		},
+	};

+module_i2c_driver(mlx90393_i2c_driver);

Subject: [PATCH v3 0/2] iio: magnetometer: add support for Melexis MLX90393