driver: bmm150 measurement compensation

Using Bosh reference document, compensate X,Y,Z axis
based on internal registers and R HALL values.

Change compass unites to 1/16 uT per LSB.

Reference:
https://github.com/suribi/Thunder-Kernel/blob/master/mediatek/custom/common/kernel/magnetometer/bmm150/bmm150.c

BRANCH=smaug
TEST=Check compass value in user space.
BUG=chrome-os-partner:39900

Change-Id: I0c480521771ef6004ac6e5182cc1d27e82c5bc7c
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/285020
Reviewed-by: Alec Berg <alecaberg@chromium.org>

1 files changed, 214 insertions, 0 deletions

diff --git a/driver/mag_bmm150.c b/driver/mag_bmm150.c
new file mode 100644
index 0000000000..54a4598e77
--- /dev/null
+++ b/driver/mag_bmm150.c
@@ -0,0 +1,214 @@
+/* Copyright 2015 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * BMM150 compass behing a BMI160
+ */
+
+#include "accelgyro.h"
+#include "common.h"
+#include "console.h"
+#include "driver/accelgyro_bmi160.h"
+#include "driver/mag_bmm150.h"
+#include "hooks.h"
+#include "i2c.h"
+#include "task.h"
+#include "timer.h"
+#include "util.h"
+
+#define CPUTS(outstr) cputs(CC_ACCEL, outstr)
+#define CPRINTF(format, args...) cprintf(CC_ACCEL, format, ## args)
+#define CPRINTS(format, args...) cprints(CC_ACCEL, format, ## args)
+
+
+/****************************************************************************
+* Copyright (C) 2011 - 2014 Bosch Sensortec GmbH
+*
+****************************************************************************/
+/***************************************************************************
+* License:
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*
+*   Redistributions of source code must retain the above copyright
+*   notice, this list of conditions and the following disclaimer.
+*
+*   Redistributions in binary form must reproduce the above copyright
+*   notice, this list of conditions and the following disclaimer in the
+*   documentation and/or other materials provided with the distribution.
+*
+*   Neither the name of the copyright holder nor the names of the
+*   contributors may be used to endorse or promote products derived from
+*   this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
+*
+* The information provided is believed to be accurate and reliable.
+* The copyright holder assumes no responsibility for the consequences of use
+* of such information nor for any infringement of patents or
+* other rights of third parties which may result from its use.
+* No license is granted by implication or otherwise under any patent or
+* patent rights of the copyright holder.
+*/
+
+#include "mag_bmm150.h"
+
+#define BMI150_READ_16BIT_COM_REG(store_, addr_) do { \
+	int val; \
+	raw_mag_read8(s->i2c_addr, (addr_), &val); \
+	store_ = val; \
+	raw_mag_read8(s->i2c_addr, (addr_) + 1, &val); \
+	store_ |= (val << 8); \
+} while (0)
+
+
+int bmm150_init(const struct motion_sensor_t *s)
+{
+	int ret;
+	int val;
+	struct bmm150_comp_registers *regs = BMM150_COMP_REG(s);
+
+	/* Set the compass from Suspend to Sleep */
+	ret = raw_mag_write8(s->i2c_addr, BMM150_PWR_CTRL, BMM150_PWR_ON);
+	/* Now we can read the device id */
+	ret = raw_mag_read8(s->i2c_addr, BMM150_CHIP_ID, &val);
+	if (ret)
+		return EC_ERROR_UNKNOWN;
+
+	if (val != BMM150_CHIP_ID_MAJOR)
+		return EC_ERROR_ACCESS_DENIED;
+
+	/* Read the private registers for compensation */
+	ret = raw_mag_read8(s->i2c_addr, BMM150_REGA_DIG_X1, &val);
+	if (ret)
+		return EC_ERROR_UNKNOWN;
+	regs->dig1[X] = val;
+	raw_mag_read8(s->i2c_addr, BMM150_REGA_DIG_Y1, &val);
+	regs->dig1[Y] = val;
+	raw_mag_read8(s->i2c_addr, BMM150_REGA_DIG_X2, &val);
+	regs->dig2[X] = val;
+	raw_mag_read8(s->i2c_addr, BMM150_REGA_DIG_Y2, &val);
+	regs->dig2[Y] = val;
+
+	raw_mag_read8(s->i2c_addr, BMM150_REGA_DIG_XY1, &val);
+	regs->dig_xy1 = val;
+
+	raw_mag_read8(s->i2c_addr, BMM150_REGA_DIG_XY2, &val);
+	regs->dig_xy2 = val;
+
+	BMI150_READ_16BIT_COM_REG(regs->dig_z1, BMM150_REGA_DIG_Z1_LSB);
+	BMI150_READ_16BIT_COM_REG(regs->dig_z2, BMM150_REGA_DIG_Z2_LSB);
+	BMI150_READ_16BIT_COM_REG(regs->dig_z3, BMM150_REGA_DIG_Z3_LSB);
+	BMI150_READ_16BIT_COM_REG(regs->dig_z4, BMM150_REGA_DIG_Z4_LSB);
+	BMI150_READ_16BIT_COM_REG(regs->dig_xyz1, BMM150_REGA_DIG_XYZ1_LSB);
+
+	/*
+	 * Set the compass forced mode, to sleep after each measure.
+	 */
+	ret = raw_mag_write8(s->i2c_addr, BMM150_OP_CTRL,
+			BMM150_OP_MODE_FORCED << BMM150_OP_MODE_OFFSET);
+
+	return ret;
+}
+
+void bmm150_temp_compensate_xy(const struct motion_sensor_t *s,
+			       vector_3_t raw,
+			       vector_3_t comp,
+			       int r)
+{
+	int inter, axis;
+	struct bmm150_comp_registers *regs = BMM150_COMP_REG(s);
+	if (r == 0)
+		inter = 0;
+	else
+		inter = ((int)regs->dig_xyz1 << 14) / r - (1 << 14);
+
+	for (axis = X; axis <= Y; axis++) {
+		if (raw[axis] == BMM150_FLIP_OVERFLOW_ADCVAL) {
+			comp[axis] = BMM150_OVERFLOW_OUTPUT;
+			continue;
+		}
+		/*
+		 * The formula is, using 4 LSB for precision:
+		 * (mdata_x * ((((dig_xy2 * i^2 / 268435456) +
+		 *              i * dig_xy1) / 16384) + 256) *
+		 *  (dig2 + 160)) / 8192 + dig1 * 8.0f
+		 * To prevent precision loss, we calculate at << 12:
+		 * 1 / 268435456 = 1 >> 28 = 1 >> (7 + 9 + 12)
+		 * 1 / 16384 = 1 >> (-7 + 9 + 12)
+		 * 256 = 1 << (20 - 12)
+		 */
+		comp[axis] = (int)regs->dig_xy2 * ((inter * inter) >> 7);
+		comp[axis] += inter * ((int)regs->dig_xy1 << 7);
+		comp[axis] >>= 9;
+		comp[axis] += 1 << (8 + 12);
+		comp[axis] *= (int)regs->dig2[axis] + 160;
+		comp[axis] >>= 12;
+		comp[axis] *= raw[axis];
+		comp[axis] >>= 13;
+		comp[axis] += (int)regs->dig1[axis] << 3;
+	}
+}
+
+void bmm150_temp_compensate_z(const struct motion_sensor_t *s,
+			      vector_3_t raw,
+			      vector_3_t comp,
+			      int r)
+{
+	int dividend, divisor;
+	struct bmm150_comp_registers *regs = BMM150_COMP_REG(s);
+
+	if (raw[Z] == BMM150_HALL_OVERFLOW_ADCVAL) {
+		comp[Z] = BMM150_OVERFLOW_OUTPUT;
+		return;
+	}
+	/*
+	 * The formula is
+	 * ((z - dig_z4) * 131072 - dig_z3 * (r - dig_xyz1)) /
+	 * ((dig_z2 + dig_z1 * r / 32768) * 4);
+	 *
+	 * We spread 4 so we multiply by 131072 / 4 == (1<<15) only.
+	 */
+	dividend = (raw[Z] - (int)regs->dig_z4) << 15;
+	dividend -= (regs->dig_z3 * (r - (int)regs->dig_xyz1)) >> 2;
+	/* add 1 << 15 to round to next integer. */
+	divisor = (int)regs->dig_z1 * (r << 1) + (1 << 15);
+	divisor >>= 16;
+	divisor += (int)regs->dig_z2;
+	comp[Z] = dividend / divisor;
+	if (comp[Z] > (1 << 15) || comp[Z] < -(1 << 15))
+		comp[Z] = BMM150_OVERFLOW_OUTPUT;
+}
+
+void bmm150_normalize(const struct motion_sensor_t *s,
+		      vector_3_t v,
+		      uint8_t *data)
+{
+	uint16_t r;
+	vector_3_t raw;
+
+	/* X and Y are two's complement 13 bits vectors */
+	raw[X] = ((int16_t)(data[0] | (data[1] << 8))) >> 3;
+	raw[Y] = ((int16_t)(data[2] | (data[3] << 8))) >> 3;
+	/* X and Y are two's complement 15 bits vectors */
+	raw[Z] = ((int16_t)(data[4] | (data[5] << 8))) >> 1;
+
+	/* RHALL value to compensate with - unsigned 14 bits */
+	r = (data[6] | (data[7] << 8)) >> 2;
+
+	bmm150_temp_compensate_xy(s, raw, v, r);
+	bmm150_temp_compensate_z(s, raw, v, r);
+}
+