diff options
Diffstat (limited to 'drivers/misc/mpu3050/compass/mpuak8975.c')
| -rwxr-xr-x | drivers/misc/mpu3050/compass/mpuak8975.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/misc/mpu3050/compass/mpuak8975.c b/drivers/misc/mpu3050/compass/mpuak8975.c new file mode 100755 index 00000000000..991de77dbd0 --- /dev/null +++ b/drivers/misc/mpu3050/compass/mpuak8975.c @@ -0,0 +1,188 @@ +/* + $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); + +/** + * @} + */ |