495 lines
14 KiB
C
495 lines
14 KiB
C
/****************************************************************************
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* drivers/analog/ads7828.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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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <errno.h>
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#include <assert.h>
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#include <debug.h>
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#include <endian.h>
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#include <nuttx/arch.h>
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#include <nuttx/i2c/i2c_master.h>
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#include <nuttx/analog/adc.h>
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#include <nuttx/analog/ioctl.h>
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#include <nuttx/analog/ads7828.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#if defined(CONFIG_ADC_ADS7828)
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#define ADS7828_NUM_CHANNELS 8
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/* All conversions are started by writing a command byte to the ADS7828.
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* Below are the bit/ mask definitions for this byte.
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*/
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#define ADS7828_CMD_BYTE_MODE (1 << 7)
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#define ADS7828_CMD_BYTE_CHANNEL_SHIFT 4
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#define ADS7828_CMD_BYTE_CHANNEL_MASK (7 << ADS7828_CMD_BYTE_CHANNEL_SHIFT)
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#define ADS7828_CMD_BYTE_REF (1 << 3)
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#define ADS7828_CMD_BYTE_PWR_DOWN (1 << 2)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct ads7828_dev_s
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{
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FAR struct i2c_master_s *i2c;
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FAR const struct adc_callback_s *cb;
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uint8_t addr;
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/* List of channels to read on every convert trigger.
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* Bit position corresponds to channel. i.e. bit0 = 1 to read channel 0.
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*/
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uint8_t chanstrobed;
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/* Current configuration of the ADC. Encoded in its position in the
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* command byte that is sent to the ADS7828 to trigger a conversion
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*/
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uint8_t cmdbyte;
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/* ads7828 helpers */
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static int ads7828_manage_strobe(FAR struct ads7828_dev_s *priv,
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uint8_t channel, bool add_nremove);
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static int ads7828_readchannel(FAR struct ads7828_dev_s *priv,
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FAR struct adc_msg_s *msg);
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/* ADC methods */
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static int ads7828_bind(FAR struct adc_dev_s *dev,
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FAR const struct adc_callback_s *callback);
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static void ads7828_reset(FAR struct adc_dev_s *dev);
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static int ads7828_setup(FAR struct adc_dev_s *dev);
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static void ads7828_shutdown(FAR struct adc_dev_s *dev);
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static void ads7828_rxint(FAR struct adc_dev_s *dev, bool enable);
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static int ads7828_ioctl(FAR struct adc_dev_s *dev, int cmd,
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unsigned long arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct adc_ops_s g_adcops =
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{
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ads7828_bind, /* ao_bind */
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ads7828_reset, /* ao_reset */
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ads7828_setup, /* ao_setup */
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ads7828_shutdown, /* ao_shutdown */
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ads7828_rxint, /* ao_rxint */
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ads7828_ioctl /* ao_read */
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};
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static struct ads7828_dev_s g_adcpriv;
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static struct adc_dev_s g_adcdev =
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{
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&g_adcops, /* ad_ops */
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&g_adcpriv /* ad_priv */
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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: ads7828_manage_strobe
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*
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* Description:
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* Controls which channels are read on ANIOC_TRIGGER. By default all
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* channels are read.
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*
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* Returned Value:
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* 0 on success. Negated errno on failure.
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*
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****************************************************************************/
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static int ads7828_manage_strobe(FAR struct ads7828_dev_s *priv,
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uint8_t channel, bool add_nremove)
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{
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int ret = OK;
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if (priv == NULL || channel >= ADS7828_NUM_CHANNELS)
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{
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ret = -EINVAL;
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}
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else
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{
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uint8_t flag = 1U << channel;
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if (add_nremove)
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{
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priv->chanstrobed |= flag;
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}
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else
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{
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priv->chanstrobed &= ~flag;
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}
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}
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return ret;
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}
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/****************************************************************************
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* Name: ads7828_readchannel
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*
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* Description:
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* Reads a conversion from the ADC.
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*
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* Input Parameters:
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* msg - msg->am_channel should be set to the channel to be read.
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* msg->am_data will store the result of the read.
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*
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* Returned Value:
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* 0 on success. Negated errno on failure.
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*
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* Assumptions/Limitations:
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* NOTE: When used in single-ended mode, msg->am_channel will be converted
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* to the corresponding channel selection bits in the command byte.
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* In differential mode, msg->am_channel is used as the channel
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* selection bits. The corresponding "channels" are as follows:
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*
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* msg->am_channel Analog Source
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* 0 +CH0, -CH1
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* 1 +CH2, -CH3
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* 2 +CH4, -CH5
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* 3 +CH6, -CH7
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* 4 +CH1, -CH0
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* 5 +CH3, -CH2
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* 6 +CH5, -CH4
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* 7 +CH7, -CH6
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*
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****************************************************************************/
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static int ads7828_readchannel(FAR struct ads7828_dev_s *priv,
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FAR struct adc_msg_s *msg)
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{
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int ret = OK;
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if (priv == NULL || msg == NULL)
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{
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ret = -EINVAL;
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}
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else
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{
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struct i2c_msg_s i2cmsg[2];
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uint8_t channel = msg->am_channel;
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/* Convert single-ended channels to write encoding. */
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if (priv->cmdbyte & ADS7828_CMD_BYTE_MODE)
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{
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channel = channel / 2;
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if (msg->am_channel % 2 != 0)
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{
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channel += 4;
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}
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}
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uint8_t cmdbyte = channel << ADS7828_CMD_BYTE_CHANNEL_SHIFT;
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cmdbyte |= priv->cmdbyte;
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i2cmsg[0].frequency = CONFIG_ADS7828_FREQUENCY;
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i2cmsg[0].addr = priv->addr;
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i2cmsg[0].flags = I2C_M_NOSTOP;
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i2cmsg[0].buffer = &cmdbyte;
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i2cmsg[0].length = sizeof(cmdbyte);
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i2cmsg[1].frequency = CONFIG_ADS7828_FREQUENCY;
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i2cmsg[1].addr = priv->addr;
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i2cmsg[1].flags = I2C_M_READ;
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uint16_t buf;
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i2cmsg[1].buffer = (uint8_t *)(&buf);
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i2cmsg[1].length = sizeof(buf);
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ret = I2C_TRANSFER(priv->i2c, i2cmsg, 2);
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if (ret < 0)
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{
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aerr("ADS7828 I2C transfer failed: %d", ret);
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}
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msg->am_data = be16toh(buf);
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}
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return ret;
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}
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/****************************************************************************
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* Name: ads7828_bind
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*
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* Description:
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* Bind the upper-half driver callbacks to the lower-half implementation.
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* This must be called early in order to receive ADC event notifications.
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*
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****************************************************************************/
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static int ads7828_bind(FAR struct adc_dev_s *dev,
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FAR const struct adc_callback_s *callback)
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{
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FAR struct ads7828_dev_s *priv = (FAR struct ads7828_dev_s *)dev->ad_priv;
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DEBUGASSERT(priv != NULL);
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priv->cb = callback;
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return OK;
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}
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/****************************************************************************
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* Name: ads7828_reset
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*
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* Description:
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* Reset the ADC device. Called early to initialize the hardware. This
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* is called, before ao_setup() and on error conditions.
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*
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****************************************************************************/
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static void ads7828_reset(FAR struct adc_dev_s *dev)
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{
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FAR struct ads7828_dev_s *priv = (FAR struct ads7828_dev_s *)dev->ad_priv;
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priv->cmdbyte = 0;
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priv->chanstrobed = 0xffu;
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}
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/****************************************************************************
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* Name: ads7828_setup
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*
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* Description:
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* Configure the ADC. This method is called the first time that the ADC
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* device is opened. The ADS7828 is quite simple and nothing special is
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* needed to be done.
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*
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****************************************************************************/
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static int ads7828_setup(FAR struct adc_dev_s *dev)
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{
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return OK;
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}
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/****************************************************************************
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* Name: ads7828_shutdown
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*
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* Description:
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* Disable the ADC. This method is called when the ADC device is closed.
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* This method should reverse the operation of the setup method, but as
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* the ADS7828 is quite simple does not need to do anything.
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*
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****************************************************************************/
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static void ads7828_shutdown(FAR struct adc_dev_s *dev)
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{
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}
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/****************************************************************************
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* Name: ads7828_rxint
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*
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* Description:
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* Needed for ADC upper-half compatibility but conversion interrupts
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* are not supported by the ADC7828.
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*
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****************************************************************************/
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static void ads7828_rxint(FAR struct adc_dev_s *dev, bool enable)
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{
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}
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/****************************************************************************
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* Name: ads7828_ioctl
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*
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* Description:
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* All ioctl calls will be routed through this method
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*
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****************************************************************************/
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static int ads7828_ioctl(FAR struct adc_dev_s *dev, int cmd,
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unsigned long arg)
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{
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FAR struct ads7828_dev_s *priv = (FAR struct ads7828_dev_s *)dev->ad_priv;
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int ret = OK;
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switch (cmd)
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{
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case ANIOC_TRIGGER:
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{
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struct adc_msg_s msg;
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int i;
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for (i = 0; (i < ADS7828_NUM_CHANNELS) && (ret == OK); i++)
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{
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if ((priv->chanstrobed >> i) & 1u)
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{
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msg.am_channel = i;
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ret = ads7828_readchannel(priv, &msg);
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if (ret == OK)
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{
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priv->cb->au_receive(&g_adcdev, i, msg.am_data);
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}
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}
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}
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}
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break;
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/* Add a channel to list of channels read on ANIOC_TRIGGER */
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case ANIOC_ADS7828_ADD_CHAN:
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{
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ret = ads7828_manage_strobe(priv, (uint8_t)arg, true);
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}
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break;
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/* Remove a channel from list of channels read on ANIOC_TRIGGER */
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case ANIOC_ADS7828_REMOVE_CHAN:
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{
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ret = ads7828_manage_strobe(priv, (uint8_t)arg, false);
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}
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break;
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/* Read a single channel from the ADC */
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case ANIOC_ADS7828_READ_CHANNEL:
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{
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FAR struct adc_msg_s *msg = (FAR struct adc_msg_s *)arg;
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ret = ads7828_readchannel(priv, msg);
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}
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break;
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/* Set the ADC reference voltage */
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case ANIOC_ADS7828_SET_REF:
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{
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if (arg == ADS7828_REF_INTERNAL)
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{
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priv->cmdbyte |= ADS7828_CMD_BYTE_REF;
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}
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else if (arg == ADS7828_REF_EXTERNAL)
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{
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priv->cmdbyte &= ~ADS7828_CMD_BYTE_REF;
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}
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else
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{
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ret = -EINVAL;
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}
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}
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break;
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/* Set mode to single-ended or differential-mode */
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case ANIOC_ADS7828_MODE:
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{
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if (arg == ADS7828_SINGLE_ENDED)
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{
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priv->cmdbyte |= ADS7828_CMD_BYTE_MODE;
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}
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else if (arg == ADS7828_DIFFERENTIAL)
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{
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priv->cmdbyte &= ~ADS7828_CMD_BYTE_MODE;
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}
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else
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{
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ret = -EINVAL;
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}
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}
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break;
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/* Set whether to power down ADC between conversions or not */
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case ANIOC_ADS7828_POWER_SAVE:
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{
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if ((bool)arg)
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{
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priv->cmdbyte &= ~ADS7828_CMD_BYTE_PWR_DOWN;
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}
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else
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{
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priv->cmdbyte |= ADS7828_CMD_BYTE_PWR_DOWN;
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}
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}
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break;
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/* Command was not recognized */
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default:
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ret = -ENOTTY;
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aerr("ADS7828 ERROR: Unrecognized cmd: %d\n", cmd);
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break;
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}
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return ret;
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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: ads7828_initialize
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*
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* Description:
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* Initialize the selected adc
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*
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* Input Parameters:
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* i2c - Pointer to a I2C master struct for the bus the ADC resides on.
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* addr - I2C address of the ADC
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*
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* Returned Value:
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* Valid ADC device structure reference on success; a NULL on failure
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*
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****************************************************************************/
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FAR struct adc_dev_s *ads7828_initialize(FAR struct i2c_master_s *i2c,
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uint8_t addr)
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{
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DEBUGASSERT(i2c != NULL);
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/* Driver state data */
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FAR struct ads7828_dev_s *priv;
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priv = (FAR struct ads7828_dev_s *)g_adcdev.ad_priv;
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priv->cb = NULL;
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priv->i2c = i2c;
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priv->addr = addr;
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priv->cmdbyte = 0;
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priv->chanstrobed = 0xffu;
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return &g_adcdev;
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}
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#endif
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