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path: root/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
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Diffstat (limited to 'drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c')
-rw-r--r--drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c356
1 files changed, 356 insertions, 0 deletions
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
new file mode 100644
index 000000000000..02735af152c8
--- /dev/null
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
@@ -0,0 +1,356 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 TDK-InvenSense, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/string.h>
+
+#include "inv_mpu_aux.h"
+#include "inv_mpu_iio.h"
+#include "inv_mpu_magn.h"
+
+/*
+ * MPU9250 magnetometer is an AKM AK8963 chip on I2C aux bus
+ */
+#define INV_MPU_MAGN_I2C_ADDR 0x0C
+
+#define INV_MPU_MAGN_REG_WIA 0x00
+#define INV_MPU_MAGN_BITS_WIA 0x48
+
+#define INV_MPU_MAGN_REG_ST1 0x02
+#define INV_MPU_MAGN_BIT_DRDY 0x01
+#define INV_MPU_MAGN_BIT_DOR 0x02
+
+#define INV_MPU_MAGN_REG_DATA 0x03
+
+#define INV_MPU_MAGN_REG_ST2 0x09
+#define INV_MPU_MAGN_BIT_HOFL 0x08
+#define INV_MPU_MAGN_BIT_BITM 0x10
+
+#define INV_MPU_MAGN_REG_CNTL1 0x0A
+#define INV_MPU_MAGN_BITS_MODE_PWDN 0x00
+#define INV_MPU_MAGN_BITS_MODE_SINGLE 0x01
+#define INV_MPU_MAGN_BITS_MODE_FUSE 0x0F
+#define INV_MPU_MAGN_BIT_OUTPUT_BIT 0x10
+
+#define INV_MPU_MAGN_REG_CNTL2 0x0B
+#define INV_MPU_MAGN_BIT_SRST 0x01
+
+#define INV_MPU_MAGN_REG_ASAX 0x10
+#define INV_MPU_MAGN_REG_ASAY 0x11
+#define INV_MPU_MAGN_REG_ASAZ 0x12
+
+/* Magnetometer maximum frequency */
+#define INV_MPU_MAGN_FREQ_HZ_MAX 50
+
+static bool inv_magn_supported(const struct inv_mpu6050_state *st)
+{
+ switch (st->chip_type) {
+ case INV_MPU9250:
+ case INV_MPU9255:
+ return true;
+ default:
+ return false;
+ }
+}
+
+/* init magnetometer chip */
+static int inv_magn_init(struct inv_mpu6050_state *st)
+{
+ uint8_t val;
+ uint8_t asa[3];
+ int ret;
+
+ /* check whoami */
+ ret = inv_mpu_aux_read(st, INV_MPU_MAGN_I2C_ADDR, INV_MPU_MAGN_REG_WIA,
+ &val, sizeof(val));
+ if (ret)
+ return ret;
+ if (val != INV_MPU_MAGN_BITS_WIA)
+ return -ENODEV;
+
+ /* reset chip */
+ ret = inv_mpu_aux_write(st, INV_MPU_MAGN_I2C_ADDR,
+ INV_MPU_MAGN_REG_CNTL2,
+ INV_MPU_MAGN_BIT_SRST);
+ if (ret)
+ return ret;
+
+ /* read fuse ROM data */
+ ret = inv_mpu_aux_write(st, INV_MPU_MAGN_I2C_ADDR,
+ INV_MPU_MAGN_REG_CNTL1,
+ INV_MPU_MAGN_BITS_MODE_FUSE);
+ if (ret)
+ return ret;
+
+ ret = inv_mpu_aux_read(st, INV_MPU_MAGN_I2C_ADDR, INV_MPU_MAGN_REG_ASAX,
+ asa, sizeof(asa));
+ if (ret)
+ return ret;
+
+ /* switch back to power-down */
+ ret = inv_mpu_aux_write(st, INV_MPU_MAGN_I2C_ADDR,
+ INV_MPU_MAGN_REG_CNTL1,
+ INV_MPU_MAGN_BITS_MODE_PWDN);
+ if (ret)
+ return ret;
+
+ /*
+ * Sensitivity adjustement and scale to Gauss
+ *
+ * Hadj = H * (((ASA - 128) * 0.5 / 128) + 1)
+ * Factor simplification:
+ * Hadj = H * ((ASA + 128) / 256)
+ *
+ * Sensor sentivity
+ * 0.15 uT in 16 bits mode
+ * 1 uT = 0.01 G and value is in micron (1e6)
+ * sensitvity = 0.15 uT * 0.01 * 1e6
+ *
+ * raw_to_gauss = Hadj * 1500
+ */
+ st->magn_raw_to_gauss[0] = (((int32_t)asa[0] + 128) * 1500) / 256;
+ st->magn_raw_to_gauss[1] = (((int32_t)asa[1] + 128) * 1500) / 256;
+ st->magn_raw_to_gauss[2] = (((int32_t)asa[2] + 128) * 1500) / 256;
+
+ return 0;
+}
+
+/**
+ * inv_mpu_magn_probe() - probe and setup magnetometer chip
+ * @st: driver internal state
+ *
+ * Returns 0 on success, a negative error code otherwise
+ *
+ * It is probing the chip and setting up all needed i2c transfers.
+ * Noop if there is no magnetometer in the chip.
+ */
+int inv_mpu_magn_probe(struct inv_mpu6050_state *st)
+{
+ int ret;
+
+ /* quit if chip is not supported */
+ if (!inv_magn_supported(st))
+ return 0;
+
+ /* configure i2c master aux port */
+ ret = inv_mpu_aux_init(st);
+ if (ret)
+ return ret;
+
+ /* check and init mag chip */
+ ret = inv_magn_init(st);
+ if (ret)
+ return ret;
+
+ /*
+ * configure mpu i2c master accesses
+ * i2c SLV0: read sensor data, 7 bytes data(6)-ST2
+ * Byte swap data to store them in big-endian in impair address groups
+ */
+ ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0),
+ INV_MPU6050_BIT_I2C_SLV_RNW | INV_MPU_MAGN_I2C_ADDR);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0),
+ INV_MPU_MAGN_REG_DATA);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),
+ INV_MPU6050_BIT_SLV_EN |
+ INV_MPU6050_BIT_SLV_BYTE_SW |
+ INV_MPU6050_BIT_SLV_GRP |
+ INV_MPU9X50_BYTES_MAGN);
+ if (ret)
+ return ret;
+
+ /* i2c SLV1: launch single measurement */
+ ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(1),
+ INV_MPU_MAGN_I2C_ADDR);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(1),
+ INV_MPU_MAGN_REG_CNTL1);
+ if (ret)
+ return ret;
+
+ /* add 16 bits mode */
+ ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(1),
+ INV_MPU_MAGN_BITS_MODE_SINGLE |
+ INV_MPU_MAGN_BIT_OUTPUT_BIT);
+ if (ret)
+ return ret;
+
+ return regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(1),
+ INV_MPU6050_BIT_SLV_EN | 1);
+}
+
+/**
+ * inv_mpu_magn_set_rate() - set magnetometer sampling rate
+ * @st: driver internal state
+ * @fifo_rate: mpu set fifo rate
+ *
+ * Returns 0 on success, a negative error code otherwise
+ *
+ * Limit sampling frequency to the maximum value supported by the
+ * magnetometer chip. Resulting in duplicated data for higher frequencies.
+ * Noop if there is no magnetometer in the chip.
+ */
+int inv_mpu_magn_set_rate(const struct inv_mpu6050_state *st, int fifo_rate)
+{
+ uint8_t d;
+
+ /* quit if chip is not supported */
+ if (!inv_magn_supported(st))
+ return 0;
+
+ /*
+ * update i2c master delay to limit mag sampling to max frequency
+ * compute fifo_rate divider d: rate = fifo_rate / (d + 1)
+ */
+ if (fifo_rate > INV_MPU_MAGN_FREQ_HZ_MAX)
+ d = fifo_rate / INV_MPU_MAGN_FREQ_HZ_MAX - 1;
+ else
+ d = 0;
+
+ return regmap_write(st->map, INV_MPU6050_REG_I2C_SLV4_CTRL, d);
+}
+
+/**
+ * inv_mpu_magn_set_orient() - fill magnetometer mounting matrix
+ * @st: driver internal state
+ *
+ * Returns 0 on success, a negative error code otherwise
+ *
+ * Fill magnetometer mounting matrix using the provided chip matrix.
+ */
+int inv_mpu_magn_set_orient(struct inv_mpu6050_state *st)
+{
+ const char *orient;
+ char *str;
+ int i;
+
+ /* fill magnetometer orientation */
+ switch (st->chip_type) {
+ case INV_MPU9250:
+ case INV_MPU9255:
+ /* x <- y */
+ st->magn_orient.rotation[0] = st->orientation.rotation[3];
+ st->magn_orient.rotation[1] = st->orientation.rotation[4];
+ st->magn_orient.rotation[2] = st->orientation.rotation[5];
+ /* y <- x */
+ st->magn_orient.rotation[3] = st->orientation.rotation[0];
+ st->magn_orient.rotation[4] = st->orientation.rotation[1];
+ st->magn_orient.rotation[5] = st->orientation.rotation[2];
+ /* z <- -z */
+ for (i = 0; i < 3; ++i) {
+ orient = st->orientation.rotation[6 + i];
+ /* use length + 2 for adding minus sign if needed */
+ str = devm_kzalloc(regmap_get_device(st->map),
+ strlen(orient) + 2, GFP_KERNEL);
+ if (str == NULL)
+ return -ENOMEM;
+ if (strcmp(orient, "0") == 0) {
+ strcpy(str, orient);
+ } else if (orient[0] == '-') {
+ strcpy(str, &orient[1]);
+ } else {
+ str[0] = '-';
+ strcpy(&str[1], orient);
+ }
+ st->magn_orient.rotation[6 + i] = str;
+ }
+ break;
+ default:
+ st->magn_orient = st->orientation;
+ break;
+ }
+
+ return 0;
+}
+
+/**
+ * inv_mpu_magn_read() - read magnetometer data
+ * @st: driver internal state
+ * @axis: IIO modifier axis value
+ * @val: store corresponding axis value
+ *
+ * Returns 0 on success, a negative error code otherwise
+ */
+int inv_mpu_magn_read(const struct inv_mpu6050_state *st, int axis, int *val)
+{
+ unsigned int user_ctrl, status;
+ __be16 data[3];
+ uint8_t addr;
+ uint8_t d;
+ unsigned int period_ms;
+ int ret;
+
+ /* quit if chip is not supported */
+ if (!inv_magn_supported(st))
+ return -ENODEV;
+
+ /* Mag data: X - Y - Z */
+ switch (axis) {
+ case IIO_MOD_X:
+ addr = 0;
+ break;
+ case IIO_MOD_Y:
+ addr = 1;
+ break;
+ case IIO_MOD_Z:
+ addr = 2;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* set sample rate to max mag freq */
+ d = INV_MPU6050_FIFO_RATE_TO_DIVIDER(INV_MPU_MAGN_FREQ_HZ_MAX);
+ ret = regmap_write(st->map, st->reg->sample_rate_div, d);
+ if (ret)
+ return ret;
+
+ /* start i2c master, wait for xfer, stop */
+ user_ctrl = st->chip_config.user_ctrl | INV_MPU6050_BIT_I2C_MST_EN;
+ ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
+ if (ret)
+ return ret;
+
+ /* need to wait 2 periods + half-period margin */
+ period_ms = 1000 / INV_MPU_MAGN_FREQ_HZ_MAX;
+ msleep(period_ms * 2 + period_ms / 2);
+ user_ctrl = st->chip_config.user_ctrl;
+ ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
+ if (ret)
+ return ret;
+
+ /* restore sample rate */
+ d = st->chip_config.divider;
+ ret = regmap_write(st->map, st->reg->sample_rate_div, d);
+ if (ret)
+ return ret;
+
+ /* check i2c status and read raw data */
+ ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);
+ if (ret)
+ return ret;
+
+ if (status & INV_MPU6050_BIT_I2C_SLV0_NACK ||
+ status & INV_MPU6050_BIT_I2C_SLV1_NACK)
+ return -EIO;
+
+ ret = regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA,
+ data, sizeof(data));
+ if (ret)
+ return ret;
+
+ *val = (int16_t)be16_to_cpu(data[addr]);
+
+ return IIO_VAL_INT;
+}