388 lines
12 KiB
C
388 lines
12 KiB
C
/****************************************************************************
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* drivers/sensors/ina226.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 <stdlib.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 <nuttx/kmalloc.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/ina226.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#if !defined(CONFIG_I2C)
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# error i2c support required
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#endif
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#ifndef CONFIG_INA226_I2C_FREQUENCY
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# define CONFIG_INA226_I2C_FREQUENCY 400000
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#endif
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#define I2C_NOSTARTSTOP_MSGS 2
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#define I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX 0
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#define I2C_NOSTARTSTOP_DATA_MSG_INDEX 1
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#define BV_LSB 1250LU /* Bus voltage LSB in microvolts */
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#define SV_LSB 250LU /* Shunt voltage LSB in microvolts times 10 */
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct ina226_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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uint16_t config; /* INA226 config shadow */
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int32_t shunt_resistor_value; /* micro-ohms, max 2.15 kohms */
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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 ina226_write16(FAR struct ina226_dev_s *priv, uint8_t regaddr,
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FAR uint16_t regvalue);
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static int ina226_read16(FAR struct ina226_dev_s *priv, uint8_t regaddr,
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FAR uint16_t *regvalue);
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static int ina226_readpower(FAR struct ina226_dev_s *priv,
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FAR struct ina226_s *buffer);
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/* Character driver methods */
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static int ina226_open(FAR struct file *filep);
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static int ina226_close(FAR struct file *filep);
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static ssize_t ina226_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t ina226_write(FAR struct file *filep, FAR const char *buffer,
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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_ina226fops =
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{
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ina226_open, /* open */
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ina226_close, /* close */
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ina226_read, /* read */
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ina226_write, /* write */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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static int ina226_access(FAR struct ina226_dev_s *priv,
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uint8_t start_register_address, bool reading,
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FAR uint8_t *register_value, uint8_t data_length)
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{
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struct i2c_msg_s msg[I2C_NOSTARTSTOP_MSGS];
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int ret;
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msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].frequency =
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CONFIG_INA226_I2C_FREQUENCY;
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msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].addr = priv->addr;
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msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].flags = 0;
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msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].buffer = &start_register_address;
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msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].length = 1;
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msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].addr =
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msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].addr;
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msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].flags = reading ? I2C_M_READ : 0;
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msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].buffer = register_value;
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msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].length = data_length;
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ret = I2C_TRANSFER(priv->i2c, msg, I2C_NOSTARTSTOP_MSGS);
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sninfo("start_register_address: "
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"0x%02X data_length: %d register_value: 0x%02x (0x%04x) ret: %d\n",
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start_register_address, data_length, *register_value,
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*((FAR uint16_t *)register_value), ret);
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return ret;
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}
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static int ina226_read16(FAR struct ina226_dev_s *priv, uint8_t regaddr,
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FAR uint16_t *regvalue)
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{
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uint8_t buf[2];
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int ret = ina226_access(priv, regaddr, true, buf, 2);
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if (ret == 0)
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{
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*regvalue = ((uint16_t)buf[0] << 8) | (uint16_t)buf[1];
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}
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return ret;
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}
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static int ina226_write16(FAR struct ina226_dev_s *priv, uint8_t regaddr,
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FAR uint16_t regvalue)
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{
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uint8_t buf[2];
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int ret;
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buf[0] = (regvalue >> 8) & 0xff;
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buf[1] = regvalue & 0xff;
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ret = ina226_access(priv, regaddr, false, buf, 2);
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return ret;
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}
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/****************************************************************************
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* Name: ina226_readpower
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*
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* Description:
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* Read the current and voltage register with special scaling
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*
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****************************************************************************/
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static int ina226_readpower(FAR struct ina226_dev_s *priv,
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FAR struct ina226_s *buffer)
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{
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uint16_t reg;
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int64_t tmp;
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int ret;
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/* Read the raw bus voltage */
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ret = ina226_read16(priv, INA226_REG_BUS_VOLTAGE, ®);
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if (ret < 0)
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{
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snerr("ERROR: ina226_read16 failed: %d\n", ret);
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return ret;
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}
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/* Convert register value to bus voltage */
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buffer->voltage = ((uint32_t)reg) * BV_LSB; /* 1 LSB 1,25mV */
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/* Read the raw shunt voltage */
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ret = ina226_read16(priv, INA226_REG_SHUNT_VOLTAGE, ®);
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if (ret < 0)
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{
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snerr("ERROR: ina226_read16 failed: %d\n", ret);
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return ret;
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}
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tmp = ((int64_t)(int16_t)reg);
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/* Convert shunt voltage to current across the shunt resistor.
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* I(uA) = U(uV)/R(ohms)
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* = U(uV)/(R(uohms)/1000000)
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* = U(uV) * 1000000 / R(uohms)
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*
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* U(uV) = tmp*2,5
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*
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* We use a temporary 64-bit accumulator to avoid overflows.
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*/
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tmp = tmp * 2500000LL;
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tmp = tmp / (int64_t)priv->shunt_resistor_value;
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buffer->current = (int32_t)tmp;
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return OK;
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}
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/****************************************************************************
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* Name: ina226_open
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*
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* Description:
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* This function is called whenever the INA226 device is opened.
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*
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****************************************************************************/
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static int ina226_open(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct ina226_dev_s *priv = inode->i_private;
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return ina226_write16(priv, INA226_REG_CONFIG,
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priv->config | INA226_CONFIG_MODE_SBCONT);
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}
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/****************************************************************************
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* Name: ina226_close
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*
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* Description:
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* This routine is called when the INA226 device is closed.
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*
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****************************************************************************/
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static int ina226_close(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct ina226_dev_s *priv = inode->i_private;
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return ina226_write16(priv, INA226_REG_CONFIG,
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priv->config | INA226_CONFIG_MODE_PWRDOWN);
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}
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/****************************************************************************
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* Name: ina226_read
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****************************************************************************/
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static ssize_t ina226_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct ina226_dev_s *priv = inode->i_private;
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FAR struct ina226_s *ptr;
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ssize_t nsamples;
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int i;
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int ret;
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/* How many samples were requested to get? */
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nsamples = buflen / sizeof(struct ina226_s);
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ptr = (FAR struct ina226_s *)buffer;
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sninfo("buflen: %d nsamples: %d\n", buflen, nsamples);
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/* Get the requested number of samples */
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for (i = 0; i < nsamples; i++)
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{
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struct ina226_s pwr;
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/* Read the next struct ina226_s power value */
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ret = ina226_readpower(priv, &pwr);
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if (ret < 0)
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{
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snerr("ERROR: ina226_readpower failed: %d\n", ret);
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return (ssize_t)ret;
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}
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/* Save the power value in the user buffer */
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*ptr++ = pwr;
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}
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return nsamples * sizeof(struct ina226_s);
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}
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/****************************************************************************
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* Name: ina226_write
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****************************************************************************/
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static ssize_t ina226_write(FAR struct file *filep, FAR const char *buffer,
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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: ina226_register
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*
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* Description:
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* Register the INA226 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/pwrmntr0"
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* i2c - An instance of the I2C interface to use to communicate with INA226
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* addr - The I2C address of the INA226.
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* shuntval - the shunt resistor value in micro-ohms.
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* config - a combination of the constants defined earlier in this file.
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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 ina226_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
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uint8_t addr, int32_t shuntval, uint16_t config)
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{
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FAR struct ina226_dev_s *priv;
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int ret = 0;
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/* Sanity check */
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DEBUGASSERT(i2c != NULL);
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/* Initialize the ina226 device structure */
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priv = kmm_malloc(sizeof(struct ina226_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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priv->shunt_resistor_value = shuntval;
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/* Save the config (except opmode) */
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priv->config = config & ~INA226_CONFIG_MODE_MASK;
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/* Apply config, keep chip switched off */
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ret = ina226_write16(priv, INA226_REG_CONFIG,
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priv->config | INA226_CONFIG_MODE_PWRDOWN);
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if (ret < 0)
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{
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snerr("ERROR: Failed to apply config: %d\n", ret);
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goto errout;
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}
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/* Register the character driver */
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ret = register_driver(devpath, &g_ina226fops, 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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goto errout;
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}
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sninfo("(addr=0x%02x) registered at %s\n", priv->addr, devpath);
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return ret;
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errout:
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kmm_free(priv);
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return ret;
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}
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