311 lines
8.5 KiB
C
311 lines
8.5 KiB
C
/****************************************************************************
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* drivers/sensors/veml6070.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/* Character driver for the Vishay UV-A Light Sensor VEML6070 */
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <stdlib.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/signal.h>
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#include <nuttx/random.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/i2c/i2c_master.h>
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#include <nuttx/sensors/veml6070.h>
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#if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_VEML6070)
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/****************************************************************************
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* Pre-process Definitions
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****************************************************************************/
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#ifndef CONFIG_VEML6070_I2C_FREQUENCY
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# define CONFIG_VEML6070_I2C_FREQUENCY 100000
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#endif
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct veml6070_dev_s
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{
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FAR struct i2c_master_s *i2c; /* I2C interface */
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uint8_t addr; /* I2C address */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/* I2C Helpers */
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static int veml6070_read8(FAR struct veml6070_dev_s *priv, int offset,
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FAR uint8_t *regval);
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static int veml6070_write8(FAR struct veml6070_dev_s *priv,
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uint8_t regval);
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/* Character driver methods */
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static ssize_t veml6070_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t veml6070_write(FAR struct file *filep,
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FAR const char *buffer, size_t buflen);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_veml6070_fops =
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{
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NULL, /* open */
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NULL, /* close */
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veml6070_read, /* read */
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veml6070_write, /* write */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: veml6070_read8
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*
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* Description:
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* Read 8-bit register
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*
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****************************************************************************/
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static int veml6070_read8(FAR struct veml6070_dev_s *priv, int offset,
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FAR uint8_t *regval)
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{
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struct i2c_config_s config;
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uint8_t data[1];
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int ret = -1;
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/* Set up the I2C configuration */
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config.frequency = CONFIG_VEML6070_I2C_FREQUENCY;
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config.address = priv->addr + offset;
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config.addrlen = 7;
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/* Read 8-bits from the device */
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ret = i2c_read(priv->i2c, &config, data, 1);
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if (ret < 0)
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{
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snerr ("i2c_read failed: %d\n", ret);
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return ret;
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}
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/* Copy the content of the buffer to the location of the uint8_t pointer */
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*regval = data[0];
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sninfo("value: %08x ret: %d\n", *regval, ret);
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return OK;
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}
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/****************************************************************************
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* Name: veml6070_write8
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*
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* Description:
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* Write from an 8-bit register
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*
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****************************************************************************/
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static int veml6070_write8(FAR struct veml6070_dev_s *priv, uint8_t regval)
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{
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struct i2c_config_s config;
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int ret;
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sninfo("value: %02x\n", regval);
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/* Set up the I2C configuration */
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config.frequency = CONFIG_VEML6070_I2C_FREQUENCY;
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config.address = priv->addr;
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config.addrlen = 7;
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/* Write 8 bits to device */
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ret = i2c_write(priv->i2c, &config, ®val, 1);
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if (ret < 0)
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{
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snerr("ERROR: i2c_write failed: %d\n", ret);
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}
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return ret;
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}
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/****************************************************************************
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* Name: veml6070_read
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****************************************************************************/
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static ssize_t veml6070_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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int ret;
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FAR struct inode *inode;
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FAR struct veml6070_dev_s *priv;
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int msb = 1;
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uint16_t regdata;
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DEBUGASSERT(filep);
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inode = filep->f_inode;
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DEBUGASSERT(inode && inode->i_private);
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priv = (FAR struct veml6070_dev_s *)inode->i_private;
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/* Check if the user is reading the right size */
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if (buflen != 2)
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{
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snerr("ERROR: You need to read 2 bytes from this sensor!\n");
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return -EINVAL;
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}
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/* Enable the sensor */
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ret = veml6070_write8(priv, VEML6070_CMD_RSV & ~VEML6070_CMD_SD);
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if (ret < 0)
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{
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snerr("ERROR: Failed to enable the VEML6070!\n");
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return -EINVAL;
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}
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/* 1T for Rset 270Kohms is 125ms */
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nxsig_usleep(125000);
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/* Read the MSB first */
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ret = veml6070_read8(priv, msb, (FAR uint8_t *) ®data);
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if (ret < 0)
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{
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snerr("ERROR: Error reading light sensor!\n");
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return ret;
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}
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buffer[1] = regdata;
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/* Read the LSB */
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msb = 0;
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ret = veml6070_read8(priv, msb, (FAR uint8_t *) ®data);
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if (ret < 0)
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{
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snerr("ERROR: Error reading light sensor!\n");
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return ret;
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}
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buffer[0] = regdata;
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/* Feed sensor data to entropy pool */
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add_sensor_randomness((buffer[1] << 16) ^ buffer[0]);
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return buflen;
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}
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/****************************************************************************
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* Name: veml6070_write
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****************************************************************************/
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static ssize_t veml6070_write(FAR struct file *filep,
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FAR const char *buffer, size_t buflen)
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{
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return -ENOSYS;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: veml6070_register
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*
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* Description:
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* Register the VEML6070 character device as 'devpath'
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*
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* Input Parameters:
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* devpath - The full path to the driver to register. E.g., "/dev/uvlight0"
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* i2c - An instance of the I2C interface to use to communicate with
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* VEML6070
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* addr - The I2C address of the VEML6070.
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*
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* Returned Value:
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* Zero (OK) on success; a negated errno value on failure.
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*
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****************************************************************************/
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int veml6070_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
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uint8_t addr)
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{
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int ret;
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/* Sanity check */
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DEBUGASSERT(i2c != NULL);
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/* Initialize the VEML6070 device structure */
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FAR struct veml6070_dev_s *priv =
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(FAR struct veml6070_dev_s *)kmm_malloc(sizeof(struct veml6070_dev_s));
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if (priv == NULL)
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{
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snerr("ERROR: Failed to allocate instance\n");
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return -ENOMEM;
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}
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priv->i2c = i2c;
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priv->addr = addr;
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/* Initialize the device (shut it down) */
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ret = veml6070_write8(priv, VEML6070_CMD_RSV | VEML6070_CMD_SD);
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if (ret < 0)
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{
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snerr("ERROR: Failed to initialize the VEML6070!\n");
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return ret;
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}
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/* Register the character driver */
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ret = register_driver(devpath, &g_veml6070_fops, 0666, priv);
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if (ret < 0)
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{
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snerr("ERROR: Failed to register driver: %d\n", ret);
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kmm_free(priv);
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}
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return ret;
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}
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#endif /* CONFIG_I2C && CONFIG_SENSORS_VEML6070 */
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