| /**************************************************************************** |
| * drivers/analog/ads7828.c |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. The |
| * ASF licenses this file to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance with the |
| * License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| * License for the specific language governing permissions and limitations |
| * under the License. |
| * |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Included Files |
| ****************************************************************************/ |
| |
| #include <nuttx/config.h> |
| |
| #include <stdio.h> |
| #include <sys/types.h> |
| #include <stdint.h> |
| #include <stdbool.h> |
| #include <errno.h> |
| #include <assert.h> |
| #include <debug.h> |
| #include <endian.h> |
| |
| #include <nuttx/arch.h> |
| #include <nuttx/i2c/i2c_master.h> |
| #include <nuttx/analog/adc.h> |
| #include <nuttx/analog/ioctl.h> |
| #include <nuttx/analog/ads7828.h> |
| |
| /**************************************************************************** |
| * Pre-processor Definitions |
| ****************************************************************************/ |
| |
| #if defined(CONFIG_ADC_ADS7828) |
| |
| #define ADS7828_NUM_CHANNELS 8 |
| |
| /* All conversions are started by writing a command byte to the ADS7828. |
| * Below are the bit/ mask definitions for this byte. |
| */ |
| |
| #define ADS7828_CMD_BYTE_MODE (1 << 7) |
| #define ADS7828_CMD_BYTE_CHANNEL_SHIFT 4 |
| #define ADS7828_CMD_BYTE_CHANNEL_MASK (7 << ADS7828_CMD_BYTE_CHANNEL_SHIFT) |
| #define ADS7828_CMD_BYTE_REF (1 << 3) |
| #define ADS7828_CMD_BYTE_PWR_DOWN (1 << 2) |
| |
| /**************************************************************************** |
| * Private Types |
| ****************************************************************************/ |
| |
| struct ads7828_dev_s |
| { |
| FAR struct i2c_master_s *i2c; |
| FAR const struct adc_callback_s *cb; |
| uint8_t addr; |
| |
| /* List of channels to read on every convert trigger. |
| * Bit position corresponds to channel. i.e. bit0 = 1 to read channel 0. |
| */ |
| |
| uint8_t chanstrobed; |
| |
| /* Current configuration of the ADC. Encoded in its position in the |
| * command byte that is sent to the ADS7828 to trigger a conversion |
| */ |
| |
| uint8_t cmdbyte; |
| }; |
| |
| /**************************************************************************** |
| * Private Function Prototypes |
| ****************************************************************************/ |
| |
| /* ads7828 helpers */ |
| |
| static int ads7828_manage_strobe(FAR struct ads7828_dev_s *priv, |
| uint8_t channel, bool add_nremove); |
| static int ads7828_readchannel(FAR struct ads7828_dev_s *priv, |
| FAR struct adc_msg_s *msg); |
| |
| /* ADC methods */ |
| |
| static int ads7828_bind(FAR struct adc_dev_s *dev, |
| FAR const struct adc_callback_s *callback); |
| static void ads7828_reset(FAR struct adc_dev_s *dev); |
| static int ads7828_setup(FAR struct adc_dev_s *dev); |
| static void ads7828_shutdown(FAR struct adc_dev_s *dev); |
| static void ads7828_rxint(FAR struct adc_dev_s *dev, bool enable); |
| static int ads7828_ioctl(FAR struct adc_dev_s *dev, int cmd, |
| unsigned long arg); |
| |
| /**************************************************************************** |
| * Private Data |
| ****************************************************************************/ |
| |
| static const struct adc_ops_s g_adcops = |
| { |
| ads7828_bind, /* ao_bind */ |
| ads7828_reset, /* ao_reset */ |
| ads7828_setup, /* ao_setup */ |
| ads7828_shutdown, /* ao_shutdown */ |
| ads7828_rxint, /* ao_rxint */ |
| ads7828_ioctl /* ao_read */ |
| }; |
| |
| static struct ads7828_dev_s g_adcpriv; |
| |
| static struct adc_dev_s g_adcdev = |
| { |
| &g_adcops, /* ad_ops */ |
| &g_adcpriv /* ad_priv */ |
| }; |
| |
| /**************************************************************************** |
| * Private Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: ads7828_manage_strobe |
| * |
| * Description: |
| * Controls which channels are read on ANIOC_TRIGGER. By default all |
| * channels are read. |
| * |
| * Returned Value: |
| * 0 on success. Negated errno on failure. |
| * |
| ****************************************************************************/ |
| |
| static int ads7828_manage_strobe(FAR struct ads7828_dev_s *priv, |
| uint8_t channel, bool add_nremove) |
| { |
| int ret = OK; |
| |
| if (priv == NULL || channel >= ADS7828_NUM_CHANNELS) |
| { |
| ret = -EINVAL; |
| } |
| else |
| { |
| uint8_t flag = 1U << channel; |
| |
| if (add_nremove) |
| { |
| priv->chanstrobed |= flag; |
| } |
| else |
| { |
| priv->chanstrobed &= ~flag; |
| } |
| } |
| |
| return ret; |
| } |
| |
| /**************************************************************************** |
| * Name: ads7828_readchannel |
| * |
| * Description: |
| * Reads a conversion from the ADC. |
| * |
| * Input Parameters: |
| * msg - msg->am_channel should be set to the channel to be read. |
| * msg->am_data will store the result of the read. |
| * |
| * Returned Value: |
| * 0 on success. Negated errno on failure. |
| * |
| * Assumptions/Limitations: |
| * NOTE: When used in single-ended mode, msg->am_channel will be converted |
| * to the corresponding channel selection bits in the command byte. |
| * In differential mode, msg->am_channel is used as the channel |
| * selection bits. The corresponding "channels" are as follows: |
| * |
| * msg->am_channel Analog Source |
| * 0 +CH0, -CH1 |
| * 1 +CH2, -CH3 |
| * 2 +CH4, -CH5 |
| * 3 +CH6, -CH7 |
| * 4 +CH1, -CH0 |
| * 5 +CH3, -CH2 |
| * 6 +CH5, -CH4 |
| * 7 +CH7, -CH6 |
| * |
| ****************************************************************************/ |
| |
| static int ads7828_readchannel(FAR struct ads7828_dev_s *priv, |
| FAR struct adc_msg_s *msg) |
| { |
| int ret = OK; |
| if (priv == NULL || msg == NULL) |
| { |
| ret = -EINVAL; |
| } |
| else |
| { |
| struct i2c_msg_s i2cmsg[2]; |
| uint8_t channel = msg->am_channel; |
| |
| /* Convert single-ended channels to write encoding. */ |
| |
| if (priv->cmdbyte & ADS7828_CMD_BYTE_MODE) |
| { |
| channel = channel / 2; |
| |
| if (msg->am_channel % 2 != 0) |
| { |
| channel += 4; |
| } |
| } |
| |
| uint8_t cmdbyte = channel << ADS7828_CMD_BYTE_CHANNEL_SHIFT; |
| cmdbyte |= priv->cmdbyte; |
| |
| i2cmsg[0].frequency = CONFIG_ADS7828_FREQUENCY; |
| i2cmsg[0].addr = priv->addr; |
| i2cmsg[0].flags = I2C_M_NOSTOP; |
| i2cmsg[0].buffer = &cmdbyte; |
| i2cmsg[0].length = sizeof(cmdbyte); |
| |
| i2cmsg[1].frequency = CONFIG_ADS7828_FREQUENCY; |
| i2cmsg[1].addr = priv->addr; |
| i2cmsg[1].flags = I2C_M_READ; |
| |
| uint16_t buf; |
| i2cmsg[1].buffer = (uint8_t *)(&buf); |
| i2cmsg[1].length = sizeof(buf); |
| ret = I2C_TRANSFER(priv->i2c, i2cmsg, 2); |
| if (ret < 0) |
| { |
| aerr("ADS7828 I2C transfer failed: %d", ret); |
| } |
| |
| msg->am_data = be16toh(buf); |
| } |
| |
| return ret; |
| } |
| |
| /**************************************************************************** |
| * Name: ads7828_bind |
| * |
| * Description: |
| * Bind the upper-half driver callbacks to the lower-half implementation. |
| * This must be called early in order to receive ADC event notifications. |
| * |
| ****************************************************************************/ |
| |
| static int ads7828_bind(FAR struct adc_dev_s *dev, |
| FAR const struct adc_callback_s *callback) |
| { |
| FAR struct ads7828_dev_s *priv = (FAR struct ads7828_dev_s *)dev->ad_priv; |
| |
| DEBUGASSERT(priv != NULL); |
| priv->cb = callback; |
| return OK; |
| } |
| |
| /**************************************************************************** |
| * Name: ads7828_reset |
| * |
| * Description: |
| * Reset the ADC device. Called early to initialize the hardware. This |
| * is called, before ao_setup() and on error conditions. |
| * |
| ****************************************************************************/ |
| |
| static void ads7828_reset(FAR struct adc_dev_s *dev) |
| { |
| FAR struct ads7828_dev_s *priv = (FAR struct ads7828_dev_s *)dev->ad_priv; |
| |
| priv->cmdbyte = 0; |
| priv->chanstrobed = 0xffu; |
| } |
| |
| /**************************************************************************** |
| * Name: ads7828_setup |
| * |
| * Description: |
| * Configure the ADC. This method is called the first time that the ADC |
| * device is opened. The ADS7828 is quite simple and nothing special is |
| * needed to be done. |
| * |
| ****************************************************************************/ |
| |
| static int ads7828_setup(FAR struct adc_dev_s *dev) |
| { |
| return OK; |
| } |
| |
| /**************************************************************************** |
| * Name: ads7828_shutdown |
| * |
| * Description: |
| * Disable the ADC. This method is called when the ADC device is closed. |
| * This method should reverse the operation of the setup method, but as |
| * the ADS7828 is quite simple does not need to do anything. |
| * |
| ****************************************************************************/ |
| |
| static void ads7828_shutdown(FAR struct adc_dev_s *dev) |
| { |
| } |
| |
| /**************************************************************************** |
| * Name: ads7828_rxint |
| * |
| * Description: |
| * Needed for ADC upper-half compatibility but conversion interrupts |
| * are not supported by the ADC7828. |
| * |
| ****************************************************************************/ |
| |
| static void ads7828_rxint(FAR struct adc_dev_s *dev, bool enable) |
| { |
| } |
| |
| /**************************************************************************** |
| * Name: ads7828_ioctl |
| * |
| * Description: |
| * All ioctl calls will be routed through this method |
| * |
| ****************************************************************************/ |
| |
| static int ads7828_ioctl(FAR struct adc_dev_s *dev, int cmd, |
| unsigned long arg) |
| { |
| FAR struct ads7828_dev_s *priv = (FAR struct ads7828_dev_s *)dev->ad_priv; |
| int ret = OK; |
| |
| switch (cmd) |
| { |
| case ANIOC_TRIGGER: |
| { |
| struct adc_msg_s msg; |
| int i; |
| |
| for (i = 0; (i < ADS7828_NUM_CHANNELS) && (ret == OK); i++) |
| { |
| if ((priv->chanstrobed >> i) & 1u) |
| { |
| msg.am_channel = i; |
| ret = ads7828_readchannel(priv, &msg); |
| if (ret == OK) |
| { |
| priv->cb->au_receive(&g_adcdev, i, msg.am_data); |
| } |
| } |
| } |
| } |
| break; |
| |
| /* Add a channel to list of channels read on ANIOC_TRIGGER */ |
| |
| case ANIOC_ADS7828_ADD_CHAN: |
| { |
| ret = ads7828_manage_strobe(priv, (uint8_t)arg, true); |
| } |
| break; |
| |
| /* Remove a channel from list of channels read on ANIOC_TRIGGER */ |
| |
| case ANIOC_ADS7828_REMOVE_CHAN: |
| { |
| ret = ads7828_manage_strobe(priv, (uint8_t)arg, false); |
| } |
| break; |
| |
| /* Read a single channel from the ADC */ |
| |
| case ANIOC_ADS7828_READ_CHANNEL: |
| { |
| FAR struct adc_msg_s *msg = (FAR struct adc_msg_s *)arg; |
| ret = ads7828_readchannel(priv, msg); |
| } |
| break; |
| |
| /* Set the ADC reference voltage */ |
| |
| case ANIOC_ADS7828_SET_REF: |
| { |
| if (arg == ADS7828_REF_INTERNAL) |
| { |
| priv->cmdbyte |= ADS7828_CMD_BYTE_REF; |
| } |
| else if (arg == ADS7828_REF_EXTERNAL) |
| { |
| priv->cmdbyte &= ~ADS7828_CMD_BYTE_REF; |
| } |
| else |
| { |
| ret = -EINVAL; |
| } |
| } |
| break; |
| |
| /* Set mode to single-ended or differential-mode */ |
| |
| case ANIOC_ADS7828_MODE: |
| { |
| if (arg == ADS7828_SINGLE_ENDED) |
| { |
| priv->cmdbyte |= ADS7828_CMD_BYTE_MODE; |
| } |
| else if (arg == ADS7828_DIFFERENTIAL) |
| { |
| priv->cmdbyte &= ~ADS7828_CMD_BYTE_MODE; |
| } |
| else |
| { |
| ret = -EINVAL; |
| } |
| } |
| break; |
| |
| /* Set whether to power down ADC between conversions or not */ |
| |
| case ANIOC_ADS7828_POWER_SAVE: |
| { |
| if ((bool)arg) |
| { |
| priv->cmdbyte &= ~ADS7828_CMD_BYTE_PWR_DOWN; |
| } |
| else |
| { |
| priv->cmdbyte |= ADS7828_CMD_BYTE_PWR_DOWN; |
| } |
| } |
| break; |
| |
| /* Command was not recognized */ |
| |
| default: |
| ret = -ENOTTY; |
| aerr("ADS7828 ERROR: Unrecognized cmd: %d\n", cmd); |
| break; |
| } |
| |
| return ret; |
| } |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: ads7828_initialize |
| * |
| * Description: |
| * Initialize the selected adc |
| * |
| * Input Parameters: |
| * i2c - Pointer to a I2C master struct for the bus the ADC resides on. |
| * addr - I2C address of the ADC |
| * |
| * Returned Value: |
| * Valid ADC device structure reference on success; a NULL on failure |
| * |
| ****************************************************************************/ |
| |
| FAR struct adc_dev_s *ads7828_initialize(FAR struct i2c_master_s *i2c, |
| uint8_t addr) |
| { |
| DEBUGASSERT(i2c != NULL); |
| |
| /* Driver state data */ |
| |
| FAR struct ads7828_dev_s *priv; |
| priv = (FAR struct ads7828_dev_s *)g_adcdev.ad_priv; |
| |
| priv->cb = NULL; |
| priv->i2c = i2c; |
| priv->addr = addr; |
| priv->cmdbyte = 0; |
| priv->chanstrobed = 0xffu; |
| |
| return &g_adcdev; |
| } |
| |
| #endif |
