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/*
$License:
Copyright (C) 2010 InvenSense Corporation, All Rights Reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
$
*/
/**
* @defgroup COMPASSDL (Motion Library - Accelerometer Driver Layer)
* @brief Provides the interface to setup and handle an accelerometers
* connected to the secondary I2C interface of the gyroscope.
*
* @{
* @file AK8975.c
* @brief Magnetometer setup and handling methods for AKM 8975 compass.
*/
/* ------------------ */
/* - Include Files. - */
/* ------------------ */
#include <string.h>
#ifdef __KERNEL__
#include <linux/module.h>
#endif
#include "mpu.h"
#include "mlsl.h"
#include "mlos.h"
#include <log.h>
#undef MPL_LOG_TAG
#define MPL_LOG_TAG "MPL-compass"
#define AK8975_REG_ST1 (0x02)
#define AK8975_REG_HXL (0x03)
#define AK8975_REG_ST2 (0x09)
#define AK8975_REG_CNTL (0x0A)
#define AK8975_CNTL_MODE_POWER_DOWN (0x00)
#define AK8975_CNTL_MODE_SINGLE_MEASUREMENT (0x01)
int ak8975_suspend(void *mlsl_handle,
struct ext_slave_descr *slave,
struct ext_slave_platform_data *pdata)
{
int result = ML_SUCCESS;
result =
MLSLSerialWriteSingle(mlsl_handle, pdata->address,
AK8975_REG_CNTL,
AK8975_CNTL_MODE_POWER_DOWN);
MLOSSleep(1); /* wait at least 100us */
ERROR_CHECK(result);
return result;
}
int ak8975_resume(void *mlsl_handle,
struct ext_slave_descr *slave,
struct ext_slave_platform_data *pdata)
{
int result = ML_SUCCESS;
result =
MLSLSerialWriteSingle(mlsl_handle, pdata->address,
AK8975_REG_CNTL,
AK8975_CNTL_MODE_SINGLE_MEASUREMENT);
ERROR_CHECK(result);
return result;
}
int ak8975_read(void *mlsl_handle,
struct ext_slave_descr *slave,
struct ext_slave_platform_data *pdata, unsigned char *data)
{
unsigned char regs[8];
unsigned char *stat = ®s[0];
unsigned char *stat2 = ®s[7];
int result = ML_SUCCESS;
int status = ML_SUCCESS;
result =
MLSLSerialRead(mlsl_handle, pdata->address, AK8975_REG_ST1,
8, regs);
ERROR_CHECK(result);
/*
* ST : data ready -
* Measurement has been completed and data is ready to be read.
*/
if (*stat & 0x01) {
memcpy(data, ®s[1], 6);
status = ML_SUCCESS;
}
/*
* ST2 : data error -
* occurs when data read is started outside of a readable period;
* data read would not be correct.
* Valid in continuous measurement mode only.
* In single measurement mode this error should not occour but we
* stil account for it and return an error, since the data would be
* corrupted.
* DERR bit is self-clearing when ST2 register is read.
*/
if (*stat2 & 0x04)
status = ML_ERROR_COMPASS_DATA_ERROR;
/*
* ST2 : overflow -
* the sum of the absolute values of all axis |X|+|Y|+|Z| < 2400uT.
* This is likely to happen in presence of an external magnetic
* disturbance; it indicates, the sensor data is incorrect and should
* be ignored.
* An error is returned.
* HOFL bit clears when a new measurement starts.
*/
if (*stat2 & 0x08)
status = ML_ERROR_COMPASS_DATA_OVERFLOW;
/*
* ST : overrun -
* the previous sample was not fetched and lost.
* Valid in continuous measurement mode only.
* In single measurement mode this error should not occour and we
* don't consider this condition an error.
* DOR bit is self-clearing when ST2 or any meas. data register is
* read.
*/
if (*stat & 0x02) {
/* status = ML_ERROR_COMPASS_DATA_UNDERFLOW; */
status = ML_SUCCESS;
}
/*
* trigger next measurement if:
* - stat is non zero;
* - if stat is zero and stat2 is non zero.
* Won't trigger if data is not ready and there was no error.
*/
if (*stat != 0x00 || *stat2 != 0x00) {
result =
MLSLSerialWriteSingle(mlsl_handle, pdata->address,
AK8975_REG_CNTL,
AK8975_CNTL_MODE_SINGLE_MEASUREMENT);
ERROR_CHECK(result);
}
return status;
}
struct ext_slave_descr ak8975_descr = {
/*.init = */ NULL,
/*.exit = */ NULL,
/*.suspend = */ ak8975_suspend,
/*.resume = */ ak8975_resume,
/*.read = */ ak8975_read,
/*.config = */ NULL,
/*.get_config = */ NULL,
/*.name = */ "ak8975",
/*.type = */ EXT_SLAVE_TYPE_COMPASS,
/*.id = */ COMPASS_ID_AKM,
/*.reg = */ 0x01,
/*.len = */ 9,
/*.endian = */ EXT_SLAVE_LITTLE_ENDIAN,
/*.range = */ {9830, 4000}
};
struct ext_slave_descr *ak8975_get_slave_descr(void)
{
return &ak8975_descr;
}
EXPORT_SYMBOL(ak8975_get_slave_descr);
/**
* @}
*/
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