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incubator-nuttx/drivers/sensors/mlx90393.c

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/****************************************************************************
* drivers/sensors/mlx90393.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <string.h>
#include <nuttx/kmalloc.h>
#include <nuttx/wqueue.h>
#include <nuttx/fs/fs.h>
#include <nuttx/mutex.h>
#include <nuttx/sensors/mlx90393.h>
#include <nuttx/random.h>
#if defined(CONFIG_SPI) && defined(CONFIG_SENSORS_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 */
mutex_t datalock; /* 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);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_mlx90393_fops =
{
mlx90393_open, /* open */
mlx90393_close, /* close */
mlx90393_read, /* read */
mlx90393_write, /* write */
};
/* 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 (Continuous 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);
/* Acquire the mutex before the data is copied */
ret = nxmutex_lock(&dev->datalock);
if (ret != OK)
{
snerr("ERROR: Could not acquire dev->datalock: %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 mutex */
nxmutex_unlock(&dev->datalock);
/* 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, &reg_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(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 */
/* Acquire the mutex before the data is copied */
ret = nxmutex_lock(&priv->datalock);
if (ret < 0)
{
snerr("ERROR: Could not acquire priv->datalock: %d\n", ret);
return ret;
}
data = (FAR struct mlx90393_sensor_data_s *)buffer;
memset(data, 0, sizeof(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 mutex */
nxmutex_unlock(&priv->datalock);
return sizeof(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;
}
/****************************************************************************
* 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;
nxmutex_init(&priv->datalock); /* Initialize sensor data access mutex */
/* 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");
nxmutex_destroy(&priv->datalock);
kmm_free(priv);
return ret;
}
/* 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);
nxmutex_destroy(&priv->datalock);
kmm_free(priv);
return ret;
}
/* 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_SENSORS_MLX90393 */
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