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nuttx/drivers/sensors/l3gd20.c

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/****************************************************************************
* drivers/sensors/l3gd20.c
* Character driver for the ST L3GD20 3-Axis gyroscope.
*
* 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 <errno.h>
#include <debug.h>
#include <stdlib.h>
#include <string.h>
#include <nuttx/kmalloc.h>
#include <nuttx/wqueue.h>
#include <nuttx/random.h>
#include <nuttx/fs/fs.h>
#include <nuttx/sensors/l3gd20.h>
#if defined(CONFIG_SPI) && defined(CONFIG_SENSORS_L3GD20)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#if !defined(CONFIG_SCHED_HPWORK)
# error Hi-priority work queue support is required (CONFIG_SCHED_HPWORK)
#endif
/****************************************************************************
* Private Types
****************************************************************************/
struct l3gd20_dev_s
{
FAR struct l3gd20_dev_s *flink; /* Supports a singly linked list of
* drivers */
FAR struct spi_dev_s *spi; /* Pointer to the SPI instance */
FAR struct l3gd20_config_s *config; /* Pointer to the configuration of the
* L3GD20 sensor */
sem_t datasem; /* Manages exclusive access to this
* structure */
struct l3gd20_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
****************************************************************************/
#ifdef CONFIG_DEBUG_SENSORS_INFO
static void l3gd20_read_register(FAR struct l3gd20_dev_s *dev,
uint8_t const reg_addr, uint8_t *reg_data);
#endif
static void l3gd20_write_register(FAR struct l3gd20_dev_s *dev,
uint8_t const reg_addr,
uint8_t const reg_data);
static void l3gd20_reset(FAR struct l3gd20_dev_s *dev);
static void l3gd20_read_measurement_data(FAR struct l3gd20_dev_s *dev);
static void l3gd20_read_gyroscope_data(FAR struct l3gd20_dev_s *dev,
uint16_t *x_gyr, uint16_t *y_gyr,
uint16_t *z_gyr);
static void l3gd20_read_temperature(FAR struct l3gd20_dev_s *dev,
uint8_t * temperature);
static int l3gd20_interrupt_handler(int irq, FAR void *context,
FAR void *arg);
static void l3gd20_worker(FAR void *arg);
static int l3gd20_open(FAR struct file *filep);
static int l3gd20_close(FAR struct file *filep);
static ssize_t l3gd20_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t l3gd20_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int l3gd20_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_l3gd20_fops =
{
l3gd20_open,
l3gd20_close,
l3gd20_read,
l3gd20_write,
NULL,
l3gd20_ioctl,
NULL
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, NULL
#endif
};
/* Single linked list to store instances of drivers */
static struct l3gd20_dev_s *g_l3gd20_list = NULL;
/****************************************************************************
* Private Functions
****************************************************************************/
#ifdef CONFIG_DEBUG_SENSORS_INFO
/****************************************************************************
* Name: l3gd20_read_register
****************************************************************************/
static void l3gd20_read_register(FAR struct l3gd20_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 L3GD20 */
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 L3GD20 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
#endif
/****************************************************************************
* Name: l3gd20_write_register
****************************************************************************/
static void l3gd20_write_register(FAR struct l3gd20_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 L3GD20 */
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 L3GD20 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: l3gd20_reset
****************************************************************************/
static void l3gd20_reset(FAR struct l3gd20_dev_s *dev)
{
/* Reboot memory content */
l3gd20_write_register(dev, L3GD20_CTRL_REG_5, L3GD20_CTRL_REG_5_BOOT_BM);
up_mdelay(100);
}
/****************************************************************************
* Name: l3gd20_read_measurement_data
****************************************************************************/
static void l3gd20_read_measurement_data(FAR struct l3gd20_dev_s *dev)
{
uint16_t x_gyr = 0;
uint16_t y_gyr = 0;
uint16_t z_gyr = 0;
uint8_t temperature = 0;
int ret;
/* Read Gyroscope */
l3gd20_read_gyroscope_data(dev, &x_gyr, &y_gyr, &z_gyr);
/* Read Temperature */
l3gd20_read_temperature(dev, &temperature);
/* Acquire the semaphore before the data is copied */
ret = nxsem_wait(&dev->datasem);
if (ret < 0)
{
snerr("ERROR: Could not acquire dev->datasem: %d\n", ret);
return;
}
/* Copy retrieve data to internal data structure */
dev->data.x_gyr = (int16_t) (x_gyr);
dev->data.y_gyr = (int16_t) (y_gyr);
dev->data.z_gyr = (int16_t) (z_gyr);
/* Give back the semaphore */
nxsem_post(&dev->datasem);
/* Feed sensor data to entropy pool */
add_sensor_randomness((x_gyr << 16) ^ (y_gyr << 8) ^ (z_gyr << 0));
}
/****************************************************************************
* Name: l3gd20_read_gyroscope_data
****************************************************************************/
static void l3gd20_read_gyroscope_data(FAR struct l3gd20_dev_s *dev,
uint16_t * x_gyr, uint16_t * y_gyr,
uint16_t * z_gyr)
{
/* 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 L3GD20 */
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, (L3GD20_OUT_X_L_REG | 0x80 | 0x40)); /* RX */
*x_gyr = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
*x_gyr |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
*y_gyr = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
*y_gyr |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
*z_gyr = ((uint16_t) (SPI_SEND(dev->spi, 0)) << 0); /* LSB */
*z_gyr |= ((uint16_t) (SPI_SEND(dev->spi, 0)) << 8); /* MSB */
/* Set CS to high which deselects the L3GD20 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: l3gd20_read_temperature
****************************************************************************/
static void l3gd20_read_temperature(FAR struct l3gd20_dev_s *dev,
FAR uint8_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 L3GD20 */
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
*/
SPI_SEND(dev->spi, (L3GD20_OUT_TEMP_REG | 0x80));
/* RX */
*temperature = (SPI_SEND(dev->spi, 0));
/* Set CS to high which deselects the L3GD20 */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: l3gd20_interrupt_handler
****************************************************************************/
static int l3gd20_interrupt_handler(int irq, FAR void *context,
FAR void *arg)
{
/* This function should be called upon a rising edge on the L3GD20 new data
* interrupt pin since it signals that new data has been measured.
*/
FAR struct l3gd20_dev_s *priv = 0;
int ret;
/* Find out which L3GD20 device caused the interrupt */
for (priv = g_l3gd20_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, l3gd20_worker, priv, 0);
if (ret < 0)
{
snerr("ERROR: Failed to queue work: %d\n", ret);
return ret;
}
return OK;
}
/****************************************************************************
* Name: l3gd20_worker
****************************************************************************/
static void l3gd20_worker(FAR void *arg)
{
FAR struct l3gd20_dev_s *priv = (FAR struct l3gd20_dev_s *)(arg);
DEBUGASSERT(priv != NULL);
/* Read out the latest sensor data */
l3gd20_read_measurement_data(priv);
}
/****************************************************************************
* Name: l3gd20_open
****************************************************************************/
static int l3gd20_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct l3gd20_dev_s *priv = inode->i_private;
#ifdef CONFIG_DEBUG_SENSORS_INFO
uint8_t reg_content;
uint8_t reg_addr;
#endif
DEBUGASSERT(priv != NULL);
/* Perform a reset */
l3gd20_reset(priv);
/* Enable DRDY signal on INT 2 */
l3gd20_write_register(priv,
L3GD20_CTRL_REG_3,
L3GD20_CTRL_REG_3_I2_DRDY_BM);
/* Enable the maximum full scale mode.
* Enable block data update for gyro sensor data.
* This should prevent race conditions when reading sensor data.
*/
l3gd20_write_register(priv,
L3GD20_CTRL_REG_4,
L3GD20_CTRL_REG_4_BDU_BM |
L3GD20_CTRL_REG_4_FS_1_BM |
L3GD20_CTRL_REG_4_FS_0_BM);
/* Enable X,Y,Z axis
* DR=00 -> Output data rate = 95 Hz, Cut-off = 12.5
*/
l3gd20_write_register(priv,
L3GD20_CTRL_REG_1,
L3GD20_CTRL_REG_1_POWERDOWN_BM |
L3GD20_CTRL_REG_1_X_EN_BM |
L3GD20_CTRL_REG_1_Y_EN_BM |
L3GD20_CTRL_REG_1_Z_EN_BM);
/* Read measurement data to ensure DRDY is low */
l3gd20_read_measurement_data(priv);
/* Read back the content of all control registers for debug purposes */
#ifdef CONFIG_DEBUG_SENSORS_INFO
reg_content = 0;
l3gd20_read_register(priv, L3GD20_WHO_AM_I, &reg_content);
sninfo("WHO_AM_I_REG = %04x\n", reg_content);
for (reg_addr = L3GD20_CTRL_REG_1;
reg_addr <= L3GD20_CTRL_REG_5;
reg_addr++)
{
l3gd20_read_register(priv, reg_addr, &reg_content);
sninfo("R#%04x = %04x\n", reg_addr, reg_content);
}
l3gd20_read_register(priv, L3GD20_STATUS_REG, &reg_content);
sninfo("STATUS_REG = %04x\n", reg_content);
#endif
return OK;
}
/****************************************************************************
* Name: l3gd20_close
****************************************************************************/
static int l3gd20_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct l3gd20_dev_s *priv = inode->i_private;
DEBUGASSERT(priv != NULL);
/* Perform a reset */
l3gd20_reset(priv);
return OK;
}
/****************************************************************************
* Name: l3gd20_read
****************************************************************************/
static ssize_t l3gd20_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct l3gd20_dev_s *priv = inode->i_private;
FAR struct l3gd20_sensor_data_s *data;
int ret;
DEBUGASSERT(priv != NULL);
/* Check if enough memory was provided for the read call */
if (buflen < sizeof(FAR struct l3gd20_sensor_data_s))
{
snerr("ERROR: Not enough memory for reading out a sensor data"
" sample\n");
return -ENOSYS;
}
/* Acquire the semaphore before the data is copied */
ret = nxsem_wait(&priv->datasem);
if (ret < 0)
{
snerr("ERROR: Could not acquire priv->datasem: %d\n", ret);
return ret;
}
/* Copy the sensor data into the buffer */
data = (FAR struct l3gd20_sensor_data_s *)buffer;
memset(data, 0, sizeof(FAR struct l3gd20_sensor_data_s));
data->x_gyr = priv->data.x_gyr;
data->y_gyr = priv->data.y_gyr;
data->z_gyr = priv->data.z_gyr;
data->temperature = priv->data.temperature;
/* Give back the semaphore */
nxsem_post(&priv->datasem);
return sizeof(FAR struct l3gd20_sensor_data_s);
}
/****************************************************************************
* Name: l3gd20_write
****************************************************************************/
static ssize_t l3gd20_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: l3gd20_ioctl
****************************************************************************/
static int l3gd20_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
int ret = OK;
switch (cmd)
{
/* @TODO */
/* Command was not recognized */
default:
snerr("ERROR: Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: l3gd20_register
*
* Description:
* Register the L3DF20 character device as 'devpath'.
*
* Input Parameters:
* devpath - The full path to the driver to register, e.g., "/dev/gyr0".
* spi - An SPI driver instance.
* config - configuration for the L3GD20 driver.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int l3gd20_register(FAR const char *devpath, FAR struct spi_dev_s *spi,
FAR struct l3gd20_config_s *config)
{
FAR struct l3gd20_dev_s *priv;
int ret = OK;
/* Sanity check */
DEBUGASSERT(spi != NULL);
DEBUGASSERT(config != NULL);
/* Initialize the L3GD20 device structure */
priv = (FAR struct l3gd20_dev_s *)kmm_malloc(sizeof(struct l3gd20_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
ret = -ENOMEM;
goto errout;
}
priv->spi = spi;
priv->config = config;
priv->work.worker = NULL;
priv->data.x_gyr = 0;
priv->data.y_gyr = 0;
priv->data.z_gyr = 0;
priv->data.temperature = 0;
/* Initialize sensor data access semaphore */
nxsem_init(&priv->datasem, 0, 1);
/* Setup SPI frequency and mode */
SPI_SETFREQUENCY(spi, L3GD20_SPI_FREQUENCY);
SPI_SETMODE(spi, L3GD20_SPI_MODE);
/* Attach the interrupt handler */
ret = priv->config->attach(priv->config, &l3gd20_interrupt_handler);
if (ret < 0)
{
snerr("ERROR: Failed to attach interrupt\n");
goto errout;
}
/* Register the character driver */
ret = register_driver(devpath, &g_l3gd20_fops, 0666, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register driver: %d\n", ret);
kmm_free(priv);
nxsem_destroy(&priv->datasem);
goto errout;
}
/* Since we support multiple L3GD20 devices, 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_l3gd20_list;
g_l3gd20_list = priv;
errout:
return ret;
}
#endif /* CONFIG_SPI && CONFIG_SENSORS_L3GD20 */
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