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incubator-nuttx/drivers/sensors/lis3mdl.c

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/****************************************************************************
* drivers/sensors/lis3mdl.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/random.h>
#include <nuttx/fs/fs.h>
#include <nuttx/mutex.h>
#include <nuttx/sensors/lis3mdl.h>
#if defined(CONFIG_SPI) && defined(CONFIG_SENSORS_LIS3MDL)
/****************************************************************************
* Private
****************************************************************************/
struct lis3mdl_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 */
int16_t temperature; /* Measurement result for temperature sensor */
};
struct lis3mdl_dev_s
{
FAR struct lis3mdl_dev_s *flink; /* Supports a singly linked list of
* drivers */
FAR struct spi_dev_s *spi; /* Pointer to the SPI instance */
FAR struct lis3mdl_config_s *config; /* Pointer to the configuration
* of the LIS3MDL sensor */
mutex_t datalock; /* Manages exclusive access to this
* structure */
struct lis3mdl_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 lis3mdl_read_register(FAR struct lis3mdl_dev_s *dev,
uint8_t const reg_addr,
uint8_t *reg_data);
static void lis3mdl_write_register(FAR struct lis3mdl_dev_s *dev,
uint8_t const reg_addr,
uint8_t const reg_data);
static void lis3mdl_reset(FAR struct lis3mdl_dev_s *dev);
static void lis3mdl_read_measurement_data(FAR struct lis3mdl_dev_s *dev);
static void lis3mdl_read_magnetic_data(FAR struct lis3mdl_dev_s *dev,
uint16_t *x_mag, uint16_t *y_mag,
uint16_t *z_mag);
static void lis3mdl_read_temperature(FAR struct lis3mdl_dev_s *dev,
uint16_t *temperature);
static int lis3mdl_interrupt_handler(int irq, FAR void *context);
static void lis3mdl_worker(FAR void *arg);
static int lis3mdl_open(FAR struct file *filep);
static int lis3mdl_close(FAR struct file *filep);
static ssize_t lis3mdl_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t lis3mdl_write(FAR struct file *filep,
FAR const char *buffer,
size_t buflen);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_lis3mdl_fops =
{
lis3mdl_open, /* open */
lis3mdl_close, /* close */
lis3mdl_read, /* read */
lis3mdl_write, /* write */
};
/* Single linked list to store instances of drivers */
static struct lis3mdl_dev_s *g_lis3mdl_list = 0;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: lis3mdl_read_register
****************************************************************************/
static void lis3mdl_read_register(FAR struct lis3mdl_dev_s *dev,
uint8_t const reg_addr, uint8_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 LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Transmit the register address from where we want to read - the MSB
* needs to be set to indicate the read indication.
*/
SPI_SEND(dev->spi, reg_addr | 0x80);
/* Write an idle byte while receiving the required data */
*reg_data = (uint8_t) (SPI_SEND(dev->spi, 0));
/* Set CS to high which deselects the LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: lis3mdl_write_register
****************************************************************************/
static void lis3mdl_write_register(FAR struct lis3mdl_dev_s *dev,
uint8_t const reg_addr,
uint8_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 LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Transmit the register address from where we want to read */
SPI_SEND(dev->spi, reg_addr);
/* Transmit the content which should be written in the register */
SPI_SEND(dev->spi, reg_data);
/* Set CS to high which deselects the LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: lis3mdl_reset
****************************************************************************/
static void lis3mdl_reset(FAR struct lis3mdl_dev_s *dev)
{
lis3mdl_write_register(dev,
LIS3MDL_CTRL_REG_2,
LIS3MDL_CTRL_REG_2_SOFT_RST_BM);
up_mdelay(100);
}
/****************************************************************************
* Name: lis3mdl_interrupt_handler
****************************************************************************/
static void lis3mdl_read_measurement_data(FAR struct lis3mdl_dev_s *dev)
{
/* Magnetic data */
uint16_t x_mag = 0;
uint16_t y_mag = 0;
uint16_t z_mag = 0;
lis3mdl_read_magnetic_data(dev, &x_mag, &y_mag, &z_mag);
/* Temperature */
uint16_t temperature = 0;
lis3mdl_read_temperature(dev, &temperature);
/* Acquire the mutex before the data is copied */
int 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.x_mag = (int16_t) (x_mag);
dev->data.y_mag = (int16_t) (y_mag);
dev->data.z_mag = (int16_t) (z_mag);
dev->data.temperature = (int16_t) (temperature);
/* Give back the mutex */
nxmutex_unlock(&dev->datalock);
/* Feed sensor data to entropy pool */
add_sensor_randomness((x_mag << 16) ^ (y_mag << 10) ^ (z_mag << 2) ^
temperature);
}
/****************************************************************************
* Name: lis3mdl_read_magnetic_data
****************************************************************************/
static void lis3mdl_read_magnetic_data(FAR struct lis3mdl_dev_s *dev,
uint16_t * x_mag, uint16_t * y_mag,
uint16_t * z_mag)
{
/* 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 LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Transmit the register address from where we want to start reading
* 0x80 -> MSB is set -> Read Indication 0x40 -> MSB-1 (MS-Bit) is
* set -> auto increment of address when reading multiple bytes.
*/
SPI_SEND(dev->spi, (LIS3MDL_OUT_X_L_REG | 0x80 | 0x40)); /* RX */
*x_mag = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
*x_mag |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
*y_mag = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
*y_mag |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
*z_mag = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
*z_mag |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
/* Set CS to high which deselects the LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: lis3mdl_read_temperature
****************************************************************************/
static void lis3mdl_read_temperature(FAR struct lis3mdl_dev_s *dev,
uint16_t * temperature)
{
/* 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 LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
/* Transmit the register address from where we want to start reading
* 0x80 -> MSB is set -> Read Indication 0x40 -> MSB-1 (MS-Bit) is
* set -> auto increment of address when reading multiple bytes.
*/
SPI_SEND(dev->spi, (LIS3MDL_TEMP_OUT_L_REG | 0x80 | 0x40));
/* RX */
*temperature = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
*temperature |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
/* Set CS to high which deselects the LIS3MDL */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: lis3mdl_interrupt_handler
****************************************************************************/
static int lis3mdl_interrupt_handler(int irq, FAR void *context)
{
/* This function should be called upon a rising edge on the LIS3MDL DRDY
* pin since it signals that new data has been measured.
*/
FAR struct lis3mdl_dev_s *priv = 0;
int ret;
/* Find out which LIS3MDL device caused the interrupt */
for (priv = g_lis3mdl_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, lis3mdl_worker, priv, 0);
if (ret < 0)
{
snerr("ERROR: Failed to queue work: %d\n", ret);
return ret;
}
else
{
return OK;
}
}
/****************************************************************************
* Name: lis3mdl_worker
****************************************************************************/
static void lis3mdl_worker(FAR void *arg)
{
FAR struct lis3mdl_dev_s *priv = (FAR struct lis3mdl_dev_s *)(arg);
DEBUGASSERT(priv != NULL);
/* Read out the latest sensor data */
lis3mdl_read_measurement_data(priv);
}
/****************************************************************************
* Name: lis3mdl_open
****************************************************************************/
static int lis3mdl_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lis3mdl_dev_s *priv = inode->i_private;
uint8_t reg_content;
uint8_t reg_addr;
DEBUGASSERT(priv != NULL);
/* Perform a reset */
lis3mdl_reset(priv);
/* Enable * - the maximum full scale mode. * Full scale = +/- 1.6 mT (16
* Gauss).
*/
lis3mdl_write_register(priv,
LIS3MDL_CTRL_REG_2,
LIS3MDL_CTRL_REG_2_FS_1_BM |
LIS3MDL_CTRL_REG_2_FS_0_BM);
/* Enable - temperature sensor - ultra high performance mode (UMP) for X
* and Y - fast output data rates This results in a output data rate of
* 155 Hz for X and Y.
*/
lis3mdl_write_register(priv,
LIS3MDL_CTRL_REG_1,
LIS3MDL_CTRL_REG_1_TEMP_EN_BM |
LIS3MDL_CTRL_REG_1_OM_1_BM |
LIS3MDL_CTRL_REG_1_OM_0_BM |
LIS3MDL_CTRL_REG_1_FAST_ODR_BM);
/* Enable * - ultra high performance mode (UMP) for Z * This should result
* to the same output data rate as for X and Y.
*/
lis3mdl_write_register(priv,
LIS3MDL_CTRL_REG_4,
LIS3MDL_CTRL_REG_4_OMZ_1_BM |
LIS3MDL_CTRL_REG_4_OMZ_0_BM);
/* Enable * - block data update for magnetic sensor data * This should
* prevent race conditions when reading sensor data.
*/
lis3mdl_write_register(priv,
LIS3MDL_CTRL_REG_5,
LIS3MDL_CTRL_REG_5_BDU_BM);
/* Enable continuous conversion mode - the device starts measuring now. */
lis3mdl_write_register(priv, LIS3MDL_CTRL_REG_3, 0);
/* Read measurement data to ensure DRDY is low */
lis3mdl_read_measurement_data(priv);
/* Read back the content of all control registers for debug purposes */
reg_content = 0;
for (reg_addr = LIS3MDL_CTRL_REG_1;
reg_addr <= LIS3MDL_CTRL_REG_5;
reg_addr++)
{
lis3mdl_read_register(priv, reg_addr, &reg_content);
sninfo("R#%04x = %04x\n", reg_addr, reg_content);
}
lis3mdl_read_register(priv, LIS3MDL_STATUS_REG, &reg_content);
sninfo("STATUS_REG = %04x\n", reg_content);
return OK;
}
/****************************************************************************
* Name: lis3mdl_close
****************************************************************************/
static int lis3mdl_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lis3mdl_dev_s *priv = inode->i_private;
DEBUGASSERT(priv != NULL);
/* Perform a reset */
lis3mdl_reset(priv);
return OK;
}
/****************************************************************************
* Name: lis3mdl_read
****************************************************************************/
static ssize_t lis3mdl_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lis3mdl_dev_s *priv = inode->i_private;
FAR struct lis3mdl_sensor_data_s *data;
int ret;
DEBUGASSERT(priv != NULL);
/* Check if enough memory was provided for the read call */
if (buflen < sizeof(FAR struct lis3mdl_sensor_data_s))
{
snerr("ERROR: "
"Not enough memory for reading out a sensor data sample\n");
return -ENOSYS;
}
/* 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;
}
/* Copy the sensor data into the buffer */
data = (FAR struct lis3mdl_sensor_data_s *)buffer;
memset(data, 0, sizeof(FAR struct lis3mdl_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(FAR struct lis3mdl_sensor_data_s);
}
/****************************************************************************
* Name: lis3mdl_write
****************************************************************************/
static ssize_t lis3mdl_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lis3mdl_register
*
* Description:
* Register the LIS3MDL 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
* LIS3MDL
* config - configuration for the LIS3MDL driver. For details see
* description above.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int lis3mdl_register(FAR const char *devpath, FAR struct spi_dev_s *spi,
FAR struct lis3mdl_config_s const *config)
{
FAR struct lis3mdl_dev_s *priv;
int ret;
/* Sanity check */
DEBUGASSERT(spi != NULL);
DEBUGASSERT(config != NULL);
/* Initialize the LIS3MDL device structure */
priv = (FAR struct lis3mdl_dev_s *)
kmm_malloc(sizeof(struct lis3mdl_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, LIS3MDL_SPI_FREQUENCY);
SPI_SETMODE(spi, LIS3MDL_SPI_MODE);
/* Attach the interrupt handler */
ret = priv->config->attach(priv->config, &lis3mdl_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_lis3mdl_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 LIS3MDL 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_lis3mdl_list;
g_lis3mdl_list = priv;
return OK;
}
#endif /* CONFIG_SPI && CONFIG_SENSORS_LIS3MDL */
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