/**************************************************************************** * drivers/sensors/mlx90393.c * Character driver for the MLX90393 3-Axis magnetometer. * * Copyright (C) 2016 DS-Automotion GmbH. All rights reserved. * Author: Alexander Entinger * * 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 #include #include #include #include #include #include #include #include #include #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 */ 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; nxsem_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_SENSORS_MLX90393 */