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nuttx/drivers/sensors/lis3dh.c
Catalin Visinescu 081e4c478a drivers/: Multiple Drivers Are Registered With World Writable - Part 2 
Permissions (Part 2)

Description:

In kernel builds, any unprivileged process running on the NuttX
device can open /dev/efuse and attempt to read/write fuse content.
Reading the fuses may provide valuable information to an attacker
controlling the user process. The write operation, in extreme cases
where the fuse blocks are not locked, may brick the device.

DISCLAIMER: I tried to be strict with the settings, better to relax them
later if it's needed.

This is part of https://github.com/apache/nuttx/issues/19410

See https://github.com/apache/nuttx/issues/19410

Compiles ok.

Signed-off-by: Catalin Visinescu <catalin_visinescu@yahoo.com>
2026-07-15 15:27:28 +08:00

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/****************************************************************************
* drivers/sensors/lis3dh.c
*
* SPDX-License-Identifier: BSD-3-Clause
* SPDX-FileCopyrightText: Copyright (C) 2018 Extent3D. All rights reserved.
* SPDX-FileContributor: Matt Thompson <matt@extent3d.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.
*
****************************************************************************/
/* WARNING for developers:
*
* This driver uses the legacy style of writing sensor drivers for NuttX. The
* project has since decided to adopt a new sensor framework in order to
* have a consistent API and feature-set.
*
* Sensors which use the uORB framework are typically suffixed "_uorb". You
* can also visit the documentation about the new sensor framework to learn
* more.
*/
#warning "This is a deprecated legacy sensor driver."
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/debug.h>
#include <string.h>
#include <nuttx/arch.h>
#include <nuttx/kmalloc.h>
#include <nuttx/wqueue.h>
#include <nuttx/random.h>
#include <nuttx/fs/fs.h>
#include <nuttx/mutex.h>
#include <nuttx/semaphore.h>
#include <nuttx/sensors/lis3dh.h>
#include <nuttx/sensors/ioctl.h>
#if defined(CONFIG_SPI) && defined(CONFIG_LIS3DH)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define LIS3DH_QUEUE_MAX 32
#define LIS3DH_FIFOBUF_SIZE ((32 * 6) + 1)
/****************************************************************************
* Private Types
****************************************************************************/
struct lis3dh_dev_s
{
FAR struct lis3dh_config_s *config; /* Driver configuration */
FAR struct spi_dev_s *spi; /* Pointer to the SPI instance */
struct work_s work; /* Work Queue */
uint8_t power_mode; /* The power mode used to determine mg/digit */
uint8_t odr; /* The current output data rate */
sem_t readsem; /* Read notification semaphore */
uint8_t fifobuf[LIS3DH_FIFOBUF_SIZE]; /* Raw FIFO buffer */
struct lis3dh_sensor_data_s queue[LIS3DH_QUEUE_MAX];
mutex_t queuelock; /* Queue exclusive lock */
uint8_t queue_rpos; /* Queue read position */
uint8_t queue_wpos; /* Queue write position */
uint8_t queue_count; /* Number of elements in the queue */
};
struct lis3dh_sample_s
{
int16_t x;
int16_t y;
int16_t z;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static void lis3dh_read_register(FAR struct lis3dh_dev_s *dev,
uint8_t const reg_addr, uint8_t *reg_data);
static void lis3dh_write_register(FAR struct lis3dh_dev_s *dev,
uint8_t const reg_addr,
uint8_t const reg_data);
static void lis3dh_reset(FAR struct lis3dh_dev_s *dev);
static int lis3dh_ident(FAR struct lis3dh_dev_s *dev);
static int lis3dh_read_fifo(FAR struct lis3dh_dev_s *dev);
static int lis3dh_interrupt_handler(int irq, FAR void *context,
FAR void *arg);
static void lis3dh_worker(FAR void *arg);
static int lis3dh_irq_enable(FAR struct lis3dh_dev_s *dev, bool enable);
static int lis3dh_fifo_enable(FAR struct lis3dh_dev_s *dev);
static int lis3dh_open(FAR struct file *filep);
static int lis3dh_close(FAR struct file *filep);
static ssize_t lis3dh_read(FAR struct file *, FAR char *buffer,
size_t buflen);
static ssize_t lis3dh_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int lis3dh_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_lis3dh_fops =
{
lis3dh_open, /* open */
lis3dh_close, /* close */
lis3dh_read, /* read */
lis3dh_write, /* write */
NULL, /* seek */
lis3dh_ioctl, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: lis3dh_read_register
*
* Description:
* Read a single register from the LIS3DH sensor.
*
* Input Parameters:
* dev - Pointer to device driver instance
* reg_addr - LIS3DH register address
* reg_data - Pointer to uint8_t where read value will be stored
*
****************************************************************************/
static void lis3dh_read_register(FAR struct lis3dh_dev_s *dev,
uint8_t const reg_addr, uint8_t * reg_data)
{
uint8_t buffer[2];
/* 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 LIS3DH */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
buffer[0] = reg_addr | 0x80;
buffer[1] = 0;
SPI_EXCHANGE(dev->spi, buffer, buffer, 2);
*reg_data = buffer[1];
/* Set CS to high which deselects the LIS3DH */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: lis3dh_write_register
*
* Description:
* Write a single register to the LIS3DH sensor.
*
* Input Parameters:
* dev - Pointer to device driver instance
* reg_addr - LIS3DH register address
* reg_data - Value to write into the specified register address
*
****************************************************************************/
static void lis3dh_write_register(FAR struct lis3dh_dev_s *dev,
uint8_t const reg_addr,
uint8_t const reg_data)
{
uint8_t buffer[2];
/* 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 LIS3DH */
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
buffer[0] = reg_addr;
buffer[1] = reg_data;
SPI_EXCHANGE(dev->spi, buffer, buffer, 2);
/* Set CS to high which deselects the LIS3DH */
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
}
/****************************************************************************
* Name: lis3dh_reset
*
* Description:
* Perform a software reset of the LIS3DH sensor.
*
* Input Parameters:
* dev - Pointer to device driver instance
*
****************************************************************************/
static void lis3dh_reset(FAR struct lis3dh_dev_s *dev)
{
lis3dh_write_register(dev, LIS3DH_CTRL_REG5, LIS3DH_CTRL_REG5_BOOT);
up_mdelay(100);
}
/****************************************************************************
* Name: lis3dh_ident
*
* Description:
* Identify an LIS3DH sensor on the SPI bus using the WHO_AM_I register.
*
* Input Parameters:
* dev - Pointer to device driver instance
*
* Returned Value:
* OK if the device responded with the correct ID
* -ENODEV if the device did not respond with the correct ID
*
****************************************************************************/
static int lis3dh_ident(FAR struct lis3dh_dev_s *dev)
{
uint8_t reg;
lis3dh_read_register(dev, LIS3DH_WHO_AM_I, &reg);
if (reg == LIS3DH_DEVICE_ID)
{
return OK;
}
return -ENODEV;
}
/****************************************************************************
* Name: lis3dh_queue_push
*
* Description:
* Push a sensor measurement into the queue
*
* Input Parameters:
* dev - Pointer to device driver instance
*
****************************************************************************/
static int lis3dh_queue_push(FAR struct lis3dh_dev_s *dev,
struct lis3dh_sensor_data_s *data)
{
nxmutex_lock(&dev->queuelock);
if (dev->queue_count >= LIS3DH_QUEUE_MAX)
{
nxmutex_unlock(&dev->queuelock);
return -ENOMEM;
}
dev->queue_wpos++;
dev->queue[dev->queue_wpos % LIS3DH_QUEUE_MAX] = *data;
dev->queue_count++;
nxmutex_unlock(&dev->queuelock);
return OK;
}
/****************************************************************************
* Name: lis3dh_queue_pop
*
* Description:
* Pops a sensor measurement from the queue
*
* Input Parameters:
* dev - Pointer to device driver instance
*
* Returned Value:
* OK if a measurement was successfully dequeued
* -EAGAIN if the queue is empty
*
****************************************************************************/
static int lis3dh_queue_pop(FAR struct lis3dh_dev_s *dev,
struct lis3dh_sensor_data_s *data)
{
nxmutex_lock(&dev->queuelock);
if (dev->queue_count == 0)
{
nxmutex_unlock(&dev->queuelock);
return -EAGAIN;
}
dev->queue_rpos++;
*data = dev->queue[dev->queue_rpos % LIS3DH_QUEUE_MAX];
dev->queue_count--;
nxmutex_unlock(&dev->queuelock);
return OK;
}
/****************************************************************************
* Name: lis3dh_read_fifo
*
* Description:
* Reads the FIFO from the LIS3DH sensor, and pushes to the internal queue.
*
* Input Parameters:
* dev - Pointer to device driver instance
*
* Returned Value:
*
****************************************************************************/
static int lis3dh_read_fifo(FAR struct lis3dh_dev_s *dev)
{
uint8_t fifosrc;
uint8_t count;
int i;
/* Lock the SPI bus */
SPI_LOCK(dev->spi, true);
/* Read the FIFO source register */
dev->fifobuf[0] = LIS3DH_FIFO_SRC_REG | 0x80;
dev->fifobuf[1] = 0;
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
SPI_EXCHANGE(dev->spi, dev->fifobuf, dev->fifobuf, 2);
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
fifosrc = dev->fifobuf[1];
count = fifosrc & 0x1f;
if (fifosrc & LIS3DH_FIFO_SRC_REG_OVRN_FIFO)
{
snerr("FIFO overrun\n");
}
memset(dev->fifobuf, 0, LIS3DH_FIFOBUF_SIZE);
dev->fifobuf[0] = LIS3DH_OUT_X_L | 0xc0;
SPI_SELECT(dev->spi, dev->config->spi_devid, true);
SPI_EXCHANGE(dev->spi, dev->fifobuf, dev->fifobuf, 1 + count * 6);
SPI_SELECT(dev->spi, dev->config->spi_devid, false);
/* Unlock the SPI bus */
SPI_LOCK(dev->spi, false);
for (i = 0; i < count; i++)
{
struct lis3dh_sensor_data_s data;
uint16_t x_raw;
uint16_t y_raw;
uint16_t z_raw;
int16_t x_acc;
int16_t y_acc;
int16_t z_acc;
x_raw = (uint16_t)dev->fifobuf[(i * 6) + 1] |
(uint16_t)dev->fifobuf[(i * 6) + 2] << 8;
y_raw = (uint16_t)dev->fifobuf[(i * 6) + 3] |
(uint16_t)dev->fifobuf[(i * 6) + 4] << 8;
z_raw = (uint16_t)dev->fifobuf[(i * 6) + 5] |
(uint16_t)dev->fifobuf[(i * 6) + 6] << 8;
/* The sensor left justifies the data in the register, so we must
* shift it to the right depending on the selected power mode
*/
switch (dev->power_mode)
{
case LIS3DH_POWER_LOW: /* 8 bit measurements */
x_acc = (int16_t)x_raw >> 8;
y_acc = (int16_t)y_raw >> 8;
z_acc = (int16_t)z_raw >> 8;
data.x_acc = (float)x_acc * 0.016;
data.y_acc = (float)y_acc * 0.016;
data.z_acc = (float)z_acc * 0.016;
break;
case LIS3DH_POWER_NORMAL: /* 10 bit measurements */
x_acc = (int16_t)x_raw >> 6;
y_acc = (int16_t)y_raw >> 6;
z_acc = (int16_t)z_raw >> 6;
data.x_acc = (float)x_acc * 0.004;
data.y_acc = (float)y_acc * 0.004;
data.z_acc = (float)z_acc * 0.004;
break;
case LIS3DH_POWER_HIGH: /* 12 bit measurements */
x_acc = (int16_t)x_raw >> 4;
y_acc = (int16_t)y_raw >> 4;
z_acc = (int16_t)z_raw >> 4;
data.x_acc = (float)x_acc * 0.001;
data.y_acc = (float)y_acc * 0.001;
data.z_acc = (float)z_acc * 0.001;
break;
default:
snerr("Unknown power mode\n");
return -EINVAL;
}
if (lis3dh_queue_push(dev, &data) == OK)
{
nxsem_post(&dev->readsem);
}
}
return OK;
}
/****************************************************************************
* Name: lis3dh_interrupt_handler
*
* Description:
* Interrupt service routine, queues work on high priority work queue.
*
* Input Parameters:
* irq - Interrupt request number
* context - Context pointer
* arg - Pointer to device driver instance
*
* Returned Value:
* Returns OK to indicate the interrupt has been serviced.
*
****************************************************************************/
static int lis3dh_interrupt_handler(int irq, FAR void *context,
FAR void *arg)
{
/* The interrupt handler is called when the FIFO watermark is reached */
FAR struct lis3dh_dev_s *priv = (FAR struct lis3dh_dev_s *)arg;
int ret;
DEBUGASSERT(priv != NULL);
if (work_available(&priv->work))
{
ret = work_queue(HPWORK, &priv->work, lis3dh_worker, priv, 0);
if (ret < 0)
{
snerr("ERROR: Failed to queue work: %d\n", ret);
return ret;
}
}
return OK;
}
/****************************************************************************
* Name: lis3dh_worker
*
* Description:
* Worker callback executed from high priority work queue.
* Performs reading the FIFO from the sensor and pushing samples to
* the internal device driver queue.
*
* Input Parameters:
* arg - Pointer to device driver instance
*
****************************************************************************/
static void lis3dh_worker(FAR void *arg)
{
FAR struct lis3dh_dev_s *priv = (FAR struct lis3dh_dev_s *)(arg);
DEBUGASSERT(priv != NULL);
/* Read the FIFO and fill the queue */
lis3dh_read_fifo(priv);
}
/****************************************************************************
* Name: lis3dh_set_power_mode
*
* Description:
* Sets the power mode of the sensor.
*
* Input Parameters:
* dev - Pointer to device driver instance
* power_mode - LIS3DH_POWER_*
*
* Returned Value:
* OK - Power mode was set successfully
* -EINVAL - Invalid power mode argument
*
****************************************************************************/
static int lis3dh_set_power_mode(FAR struct lis3dh_dev_s *dev,
uint8_t power_mode)
{
uint8_t ctrl1;
uint8_t ctrl4;
switch (power_mode)
{
case LIS3DH_POWER_LOW:
lis3dh_read_register(dev, LIS3DH_CTRL_REG1, &ctrl1);
lis3dh_read_register(dev, LIS3DH_CTRL_REG4, &ctrl4);
ctrl1 |= LIS3DH_CTRL_REG1_LPEN;
ctrl4 &= ~LIS3DH_CTRL_REG4_HR;
lis3dh_write_register(dev, LIS3DH_CTRL_REG1, ctrl1);
lis3dh_write_register(dev, LIS3DH_CTRL_REG4, ctrl4);
break;
case LIS3DH_POWER_NORMAL:
lis3dh_read_register(dev, LIS3DH_CTRL_REG1, &ctrl1);
lis3dh_read_register(dev, LIS3DH_CTRL_REG4, &ctrl4);
ctrl1 &= ~LIS3DH_CTRL_REG1_LPEN;
ctrl4 &= ~LIS3DH_CTRL_REG4_HR;
lis3dh_write_register(dev, LIS3DH_CTRL_REG1, ctrl1);
lis3dh_write_register(dev, LIS3DH_CTRL_REG4, ctrl4);
break;
case LIS3DH_POWER_HIGH:
lis3dh_read_register(dev, LIS3DH_CTRL_REG1, &ctrl1);
lis3dh_read_register(dev, LIS3DH_CTRL_REG4, &ctrl4);
ctrl1 &= ~LIS3DH_CTRL_REG1_LPEN;
ctrl4 |= LIS3DH_CTRL_REG4_HR;
lis3dh_write_register(dev, LIS3DH_CTRL_REG1, ctrl1);
lis3dh_write_register(dev, LIS3DH_CTRL_REG4, ctrl4);
break;
default:
return -EINVAL;
break;
}
dev->power_mode = power_mode;
sninfo("Power mode set to %d\n", power_mode);
return OK;
}
/****************************************************************************
* Name: lis3dh_set_odr
*
* Description:
* Sets the output data rate of the sensor.
*
* Input Parameters:
* dev - Pointer to device driver instance
* odr - LIS3DH_ODR_*
*
* Returned Value:
* OK - Power mode was set successfully
* -EINVAL - Invalid odr argument
*
****************************************************************************/
static int lis3dh_set_odr(FAR struct lis3dh_dev_s *dev, uint8_t odr)
{
uint8_t ctrl1;
if (odr > LIS3DH_CTRL_REG1_ODR_LP_5376HZ)
{
return -EINVAL;
}
lis3dh_read_register(dev, LIS3DH_CTRL_REG1, &ctrl1);
ctrl1 |= LIS3DH_CTRL_REG1_ODR(odr) & LIS3DH_CTRL_REG1_ODR_MASK;
lis3dh_write_register(dev, LIS3DH_CTRL_REG1, ctrl1);
/* Cache the current ODR in the device structure */
dev->odr = odr;
sninfo("Output data rate set to %d\n", odr);
return OK;
}
/****************************************************************************
* Name: lis3dh_irq_enable
*
* Description:
* Enable or disable sensor interrupt generation on FIFO watermark.
*
* Input Parameters:
* dev - Pointer to device driver instance
* enable - Boolean to enable or disable the interrupt generation
*
* Returned Value:
* OK - Interrupt generation register written.
*
****************************************************************************/
static int lis3dh_irq_enable(FAR struct lis3dh_dev_s *dev, bool enable)
{
uint8_t reg;
reg = 0;
if (enable == true)
{
reg = LIS3DH_CTRL_REG3_I1_WTM;
}
lis3dh_write_register(dev, LIS3DH_CTRL_REG3, reg);
return OK;
}
/****************************************************************************
* Name: lis3dh_irq_enable
*
* Description:
* Enable or disable sensor interrupt generation on FIFO watermark.
*
* Input Parameters:
* dev - Pointer to device driver instance
* enable - Boolean to enable or disable the interrupt generation
*
* Returned Value:
* OK - Interrupt generation register written.
*
****************************************************************************/
static int lis3dh_fifo_enable(FAR struct lis3dh_dev_s *dev)
{
uint8_t reg;
lis3dh_write_register(dev, LIS3DH_FIFO_CTRL_REG,
LIS3DH_FIFO_CTRL_REG_MODE_STREAM | 28);
lis3dh_read_register(dev, LIS3DH_CTRL_REG5, &reg);
reg |= LIS3DH_CTRL_REG5_FIFO_EN;
lis3dh_write_register(dev, LIS3DH_CTRL_REG5, reg);
return OK;
}
/****************************************************************************
* Name: lis3dh_enable
*
* Description:
* Enable sensor measurements into the on-chip FIFO.
*
* Input Parameters:
* priv - Pointer to device driver instance
*
* Returned Value:
* OK - Sensor measurements enabled.
*
****************************************************************************/
static int lis3dh_enable(FAR struct lis3dh_dev_s *priv)
{
uint8_t reg;
/* Select the default power mode */
lis3dh_set_power_mode(priv, LIS3DH_POWER_NORMAL);
/* Select the default output data rate */
lis3dh_set_odr(priv, LIS3DH_ODR_1344HZ);
reg = LIS3DH_CTRL_REG4_BDU | LIS3DH_CTRL_REG4_FS_2G;
lis3dh_write_register(priv, LIS3DH_CTRL_REG4, reg);
lis3dh_fifo_enable(priv);
/* Enable X, Y, and Z axes */
lis3dh_read_register(priv, LIS3DH_CTRL_REG1, &reg);
reg |= LIS3DH_CTRL_REG1_ZEN | LIS3DH_CTRL_REG1_YEN | LIS3DH_CTRL_REG1_XEN;
lis3dh_write_register(priv, LIS3DH_CTRL_REG1, reg);
return OK;
}
/****************************************************************************
* Name: lis3dh_open
*
* Description:
* Character device open call.
*
* Input Parameters:
* filep - Pointer to struct file
*
* Returned Value:
* -ENODEV - Device was not identified on the SPI bus.
* OK - Sensor device was opened successfully.
*
****************************************************************************/
static int lis3dh_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lis3dh_dev_s *priv = inode->i_private;
DEBUGASSERT(priv != NULL);
/* Perform a reset */
lis3dh_reset(priv);
if (lis3dh_ident(priv) < 0)
{
snerr("ERROR: Failed to identify LIS3DH on SPI bus\n");
return -ENODEV;
}
/* Attach the interrupt line */
(priv->config->irq_attach)(priv->config, lis3dh_interrupt_handler, priv);
/* Enable interrupt generation on the sensor */
lis3dh_irq_enable(priv, true);
/* Enable measurements on the sensor */
if (lis3dh_enable(priv) < 0)
{
snerr("ERROR: Failed to enable LIS3DH\n");
return -ENODEV;
}
return OK;
}
/****************************************************************************
* Name: lis3dh_close
*
* Description:
* Character device close call.
*
* Input Parameters:
* filep - Pointer to struct file
*
* Returned Value:
* OK - Sensor device was closed successfully.
*
****************************************************************************/
static int lis3dh_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lis3dh_dev_s *priv = inode->i_private;
DEBUGASSERT(priv != NULL);
/* Perform a reset */
lis3dh_reset(priv);
/* Detach the interrupt line */
(priv->config->irq_detach)(priv->config);
return OK;
}
/****************************************************************************
* Name: lis3dh_read
*
* Description:
* Character device read call. Blocks until requested buffer size is full.
*
* Input Parameters:
* filep - Pointer to struct file
* buffer - Pointer to user buffer
* buflen - Size of user buffer in bytes
*
* Returned Value:
* Returns the number of bytes written to the buffer.
* -EINVAL - Supplied buffer length invalid
*
****************************************************************************/
static ssize_t lis3dh_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lis3dh_dev_s *priv = inode->i_private;
FAR struct lis3dh_sensor_data_s *data;
int count;
int remain;
DEBUGASSERT(priv != NULL);
if ((buflen % sizeof(FAR struct lis3dh_sensor_data_s)) != 0)
{
snerr("ERROR: Provided buffer must be multiple of sensor data size\n");
return -EINVAL;
}
/* Get the number of samples the user has requested */
count = buflen / sizeof(struct lis3dh_sensor_data_s);
/* Cast a pointer into the user buffer */
data = (FAR struct lis3dh_sensor_data_s *)buffer;
for (remain = count; remain > 0; remain--)
{
/* Wait for data to be available in the queue */
nxsem_wait(&priv->readsem);
/* Pop a sample off of the queue */
lis3dh_queue_pop(priv, data);
data++;
}
return count * sizeof(struct lis3dh_sensor_data_s);
}
/****************************************************************************
* Name: lis3dh_write
*
* Description:
* Character device write call. Not supported.
*
* Input Parameters:
* filep - Pointer to struct file
* buffer - Pointer to user buffer
* buflen - Size of user buffer in bytes
*
* Returned Value:
* -ENOSYS
*
****************************************************************************/
static ssize_t lis3dh_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: lis3dh_ioctl
*
* Description:
* Character device ioctl call. Sets device parameters.
*
* Input Parameters:
* filep - Pointer to struct file
* cmd - SNIOC_*
* arg - ioctl specific argument
*
* Returned Value:
* OK - The command was executed successfully.
* -ENOTTY - The request command is not applicable to the driver.
*
****************************************************************************/
static int lis3dh_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lis3dh_dev_s *priv = inode->i_private;
int ret = OK;
switch (cmd)
{
case SNIOC_SET_POWER_MODE:
ret = lis3dh_set_power_mode(priv, arg);
break;
case SNIOC_SET_DATA_RATE:
ret = lis3dh_set_odr(priv, arg);
break;
default:
snerr("ERROR: Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lis3dh_register
*
* Description:
* Register the LIS3DH character device at the specified device path
*
* Input Parameters:
* devpath - Full path of device node to register ie "/dev/accel0"
* spi - SPI bus device instance
* config - Driver instance configuration structure
*
* Returned Value:
* OK on success or a negative errno value on failure.
*
****************************************************************************/
int lis3dh_register(FAR const char *devpath, FAR struct spi_dev_s *spi,
FAR struct lis3dh_config_s *config)
{
FAR struct lis3dh_dev_s *priv;
int ret;
DEBUGASSERT(spi != NULL);
/* Initialize the LIS3DH device structure */
priv = kmm_malloc(sizeof(struct lis3dh_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->config = config;
priv->spi = spi;
priv->work.worker = NULL;
priv->queue_count = 0;
/* Initialize queue mutex */
nxmutex_init(&priv->queuelock);
/* Initialize read notification semaphore */
nxsem_init(&priv->readsem, 0, 0);
/* Setup SPI frequency and mode */
SPI_SETFREQUENCY(spi, LIS3DH_SPI_FREQUENCY);
SPI_SETMODE(spi, LIS3DH_SPI_MODE);
/* Register the character driver */
ret = register_driver(devpath, &g_lis3dh_fops, 0600, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register driver: %d\n", ret);
nxmutex_destroy(&priv->queuelock);
nxsem_destroy(&priv->readsem);
kmm_free(priv);
return ret;
}
return OK;
}
#endif /* CONFIG_SPI && CONFIG_LIS3DH */
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