/****************************************************************************
* drivers/sensors/mlx90393.c
* Character driver for the MLX90393 3-Axis magnetometer.
*
* Copyright (C) 2016 DS-Automotion GmbH. All rights reserved.
* Author: Alexander Entinger <a.entinger@ds-automotion.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name NuttX nor the names of its 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 THE
* COPYRIGHT OWNER 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <errno.h>
#include <debug.h>
#include <string.h>
#include <semaphore.h>
#include <nuttx/kmalloc.h>
#include <nuttx/wqueue.h>
#include <nuttx/fs/fs.h>
#include <nuttx/sensors/mlx90393.h>
#include <nuttx/random.h>
#if defined(CONFIG_SPI) && defined(CONFIG_MLX90393)
/****************************************************************************
* Private
****************************************************************************/
struct mlx90393_sensor_data_s
{
int16_t x_mag; /* Measurement result for x axis */
int16_t y_mag; /* Measurement result for y axis */
int16_t z_mag; /* Measurement result for z axis */
uint16_t temperature; /* Measurement result for temperature sensor */
};
struct mlx90393_dev_s
{
FAR struct mlx90393_dev_s *flink; /* Supports a singly linked list
* of drivers */
FAR struct spi_dev_s *spi; /* Pointer to the SPI instance */
FAR struct mlx90393_config_s *config; /* Pointer to the configuration of
* the MLX90393 sensor */
sem_t datasem; /* Manages exclusive access to
* this structure */
struct mlx90393_sensor_data_s data; /* The data as measured by the
* sensor */
struct work_s work; /* The work queue is responsible
* for retrieving the data from
* the sensor after the arrival of
* new data was signalled in an
* interrupt */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static void mlx90393_start_burst_mode(FAR struct mlx90393_dev_s *dev);
static void mlx90393_read_measurement_data(FAR struct mlx90393_dev_s *dev);
static void mlx90393_read_register(FAR struct mlx90393_dev_s *dev,
uint8_t const reg_addr, uint16_t *reg_data);
static void mlx90393_write_register(FAR struct mlx90393_dev_s *dev,
uint8_t const reg_addr,
uint16_t const reg_data);
static void mlx90393_reset(FAR struct mlx90393_dev_s *dev);
static int mlx90393_interrupt_handler(int irq, FAR void *context);
static void mlx90393_worker(FAR void *arg);
static int mlx90393_open(FAR struct file *filep);
static int mlx90393_close(FAR struct file *filep);
static ssize_t mlx90393_read(FAR struct file *, FAR char *, size_t);
static ssize_t mlx90393_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int mlx90393_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_mlx90393_fops =
{
mlx90393_open,
mlx90393_close,
mlx90393_read,
mlx90393_write,
NULL,
mlx90393_ioctl
#ifndef CONFIG_DISABLE_POLL
, NULL
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, NULL
#endif
};
/* Single linked list to store instances of drivers */
static struct mlx90393_dev_s *g_mlx90393_list = NULL;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mlx90393_start_burst_mode
****************************************************************************/
static void mlx90393_start_burst_mode(FAR struct mlx90393_dev_s *dev)
{
/* Lock the SPI bus so that only one device can access it at the same time */
SPI_LOCK(dev->spi, true);
/* Set CS to low which selects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Start Burst Mode (Continous Measurement on all channels) */
SPI_SEND(dev->spi, MLX90393_SB | MLX90393_ZYXT_bm);
/* Write an idle byte to retrieve the status byte */
SPI_SEND(dev->spi, 0);
/* Set CS to high which deselects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: mlx90393_read_measurement_data
****************************************************************************/
static void mlx90393_read_measurement_data(FAR struct mlx90393_dev_s *dev)
{
int ret;
/* Lock the SPI bus so that only one device can access it at the same time */
SPI_LOCK(dev->spi, true);
/* Set CS to low which selects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Issue command to read measurement data on all channels */
SPI_SEND(dev->spi, MLX90393_RM | MLX90393_ZYXT_bm);
/* Write an idle byte to retrieve the status byte */
SPI_SEND(dev->spi, 0);
/* The data is output in the following order: T (MSB), T (LSB), X (MSB), X
* (LSB), Y (MSB), Y (LSB), Z (MSB), Z (LSB)
*/
uint16_t temperature = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
temperature |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
uint16_t x_mag = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
x_mag |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
uint16_t y_mag = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
y_mag |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
uint16_t z_mag = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
z_mag |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
/* Set CS to high which deselects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
/* Aquire the semaphore before the data is copied */
ret = sem_wait(&dev->datasem);
if (ret != OK)
{
snerr("ERROR: Could not aquire dev->datasem: %d\n", ret);
return;
}
/* Copy retrieve data to internal data structure */
dev->data.temperature = temperature;
dev->data.x_mag = (int16_t) (x_mag);
dev->data.y_mag = (int16_t) (y_mag);
dev->data.z_mag = (int16_t) (z_mag);
/* Give back the semaphore */
sem_post(&dev->datasem);
/* Feed sensor data to entropy pool */
add_sensor_randomness((x_mag << 17) ^ (y_mag << 9) ^ (z_mag << 1) ^
temperature);
}
/****************************************************************************
* Name: mlx90393_start_burst_mode
****************************************************************************/
static void mlx90393_reset(FAR struct mlx90393_dev_s *dev)
{
/* Lock the SPI bus so that only one device can access it at the same time */
SPI_LOCK(dev->spi, true);
/* Set CS to low which selects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Issue reset command */
SPI_SEND(dev->spi, MLX90393_RT);
/* Write an idle byte to retrieve the status byte */
SPI_SEND(dev->spi, 0);
/* Set CS to high which deselects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
/* Wait a little so the device has time to perform a proper reset */
up_mdelay(100);
}
/****************************************************************************
* Name: mlx90393_read_register
****************************************************************************/
static void mlx90393_read_register(FAR struct mlx90393_dev_s *dev,
uint8_t const reg_addr, uint16_t *reg_data)
{
/* Lock the SPI bus so that only one device can access it at the same time */
SPI_LOCK(dev->spi, true);
/* Set CS to low which selects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Issue a read register command */
SPI_SEND(dev->spi, MLX90393_RR);
/* Send the register address which needs to be left shifted by 2 */
SPI_SEND(dev->spi, (reg_addr << 2));
/* Write an idle byte to retrieve the status byte */
SPI_SEND(dev->spi, 0);
*reg_data = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
*reg_data |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
/* Set CS to high which deselects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: mlx90393_write_register
****************************************************************************/
static void mlx90393_write_register(FAR struct mlx90393_dev_s *dev,
uint8_t const reg_addr,
uint16_t const reg_data)
{
/* Lock the SPI bus so that only one device can access it at the same time */
SPI_LOCK(dev->spi, true);
/* Set CS to low which selects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Issue a write register command */
SPI_SEND(dev->spi, MLX90393_WR);
/* Send the data high byte of the register */
SPI_SEND(dev->spi, (uint8_t) ((reg_data & 0xFF00) >> 8));
/* Send the data low byte of the register */
SPI_SEND(dev->spi, (uint8_t) (reg_data & 0x00FF));
/* Send the register address which needs to be left shifted by 2 */
SPI_SEND(dev->spi, (uint8_t) (reg_addr << 2));
/* Write an idle byte to retrieve the status byte */
SPI_SEND(dev->spi, 0);
/* Set CS to high which deselects the MLX90393 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: mlx90393_interrupt_handler
****************************************************************************/
static int mlx90393_interrupt_handler(int irq, FAR void *context)
{
/* This function should be called upon a rising edge on the MLX90393 INT pin
* since it signals that new data has been measured. (INT = DRDY).
*/
FAR struct mlx90393_dev_s *priv = 0;
int ret;
/* Find out which MLX90396 device caused the interrupt */
for (priv = g_mlx90393_list; priv && priv->config->irq != irq;
priv = priv->flink);
DEBUGASSERT(priv != NULL);
/* Task the worker with retrieving the latest sensor data. We should not do
* this in a interrupt since it might take too long. Also we cannot lock the
* SPI bus from within an interrupt.
*/
DEBUGASSERT(priv->work.worker == NULL);
ret = work_queue(HPWORK, &priv->work, mlx90393_worker, priv, 0);
if (ret < 0)
{
snerr("ERROR: Failed to queue work: %d\n", ret);
return ret;
}
else
{
return OK;
}
}
/****************************************************************************
* Name: mlx90393_worker
****************************************************************************/
static void mlx90393_worker(FAR void *arg)
{
FAR struct mlx90393_dev_s *priv = (FAR struct mlx90393_dev_s *)(arg);
DEBUGASSERT(priv != NULL);
/* Read out the latest sensor data */
mlx90393_read_measurement_data(priv);
}
/****************************************************************************
* Name: mlx90393_open
****************************************************************************/
static int mlx90393_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mlx90393_dev_s *priv = inode->i_private;
static int const NUM_REGS = 10;
int reg_addr;
DEBUGASSERT(priv != NULL);
/* Reset the device */
mlx90393_reset(priv);
#ifdef CONFIG_DEBUG_SENSORS_INFO
/* Read the content of ALL registers for debug purposes */
for (reg_addr = 0; reg_addr < NUM_REGS; reg_addr++)
{
uint16_t reg_content = 0;
mlx90393_read_register(priv, reg_addr, ®_content);
sninfo("R%d = %x\n", reg_addr, reg_content);
}
#endif
/* Start the burst mode */
mlx90393_start_burst_mode(priv);
return OK;
}
/****************************************************************************
* Name: mlx90393_close
****************************************************************************/
static int mlx90393_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mlx90393_dev_s *priv = inode->i_private;
DEBUGASSERT(priv != NULL);
/* Reset the device */
mlx90393_reset(priv);
return OK;
}
/****************************************************************************
* Name: mlx90393_read
****************************************************************************/
static ssize_t mlx90393_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mlx90393_dev_s *priv = inode->i_private;
FAR struct mlx90393_sensor_data_s *data;
int ret;
DEBUGASSERT(priv != NULL);
/* Check if enough memory was provided for the read call */
if (buflen < sizeof(FAR struct mlx90393_sensor_data_s))
{
snerr("ERROR: Not enough memory for reading out a sensor data sample\n");
return -ENOSYS;
}
/* Copy the sensor data into the buffer */
/* Aquire the semaphore before the data is copied */
ret = sem_wait(&priv->datasem);
if (ret < 0)
{
int errcode = errno;
snerr("ERROR: Could not aquire priv->datasem: %d\n", errcode);
return -errcode;
}
data = (FAR struct mlx90393_sensor_data_s *)buffer;
memset(data, 0, sizeof(FAR struct mlx90393_sensor_data_s));
data->x_mag = priv->data.x_mag;
data->y_mag = priv->data.y_mag;
data->z_mag = priv->data.z_mag;
data->temperature = priv->data.temperature;
/* Give back the semaphore */
sem_post(&priv->datasem);
return sizeof(FAR struct mlx90393_sensor_data_s);
}
/****************************************************************************
* Name: mlx90393_write
****************************************************************************/
static ssize_t mlx90393_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: mlx90393_ioctl
****************************************************************************/
static int mlx90393_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
int ret = OK;
switch (cmd)
{
/* Command was not recognized */
default:
snerr("ERROR: Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mlx90393_register
*
* Description:
* Register the MLX90393 character device as 'devpath'
*
* Input Parameters:
* devpath - The full path to the driver to register. E.g., "/dev/mag0"
* spi - An instance of the SPI interface to use to communicate with
* MLX90393
* config - Describes the configuration of the MLX90393 part.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int mlx90393_register(FAR const char *devpath, FAR struct spi_dev_s *spi,
FAR struct mlx90393_config_s *config)
{
FAR struct mlx90393_dev_s *priv;
int ret;
/* Sanity check */
DEBUGASSERT(spi != NULL);
DEBUGASSERT(config != NULL);
/* Initialize the MLX90393 device structure */
priv = (FAR struct mlx90393_dev_s *)kmm_malloc(sizeof(struct mlx90393_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->spi = spi;
priv->config = config;
priv->work.worker = NULL;
sem_init(&priv->datasem, 0, 1); /* Initialize sensor data access
* semaphore */
/* Setup SPI frequency and mode */
SPI_SETFREQUENCY(spi, MLX90393_SPI_FREQUENCY);
SPI_SETMODE(spi, MLX90393_SPI_MODE);
/* Attach the interrupt handler */
ret = priv->config->attach(priv->config, &mlx90393_interrupt_handler);
if (ret < 0)
{
snerr("ERROR: Failed to attach interrupt\n");
return -ENODEV;
}
/* Register the character driver */
ret = register_driver(devpath, &g_mlx90393_fops, 0666, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register driver: %d\n", ret);
kmm_free(priv);
sem_destroy(&priv->datasem);
return -ENODEV;
}
/* Since we support multiple MLX90393 devices are supported, we will need to
* add this new instance to a list of device instances so that it can be
* found by the interrupt handler based on the received IRQ number. */
priv->flink = g_mlx90393_list;
g_mlx90393_list = priv;
return OK;
}
#endif /* CONFIG_SPI && CONFIG_MLX90393 */