/**************************************************************************** * drivers/sensors/ina226.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 #include #include #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #if !defined(CONFIG_I2C) # error i2c support required #endif #ifndef CONFIG_INA226_I2C_FREQUENCY # define CONFIG_INA226_I2C_FREQUENCY 400000 #endif #define I2C_NOSTARTSTOP_MSGS 2 #define I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX 0 #define I2C_NOSTARTSTOP_DATA_MSG_INDEX 1 #define BV_LSB 1250LU /* Bus voltage LSB in microvolts */ #define SV_LSB 250LU /* Shunt voltage LSB in microvolts times 10 */ /**************************************************************************** * Private Types ****************************************************************************/ struct ina226_dev_s { FAR struct i2c_master_s *i2c; /* I2C interface */ uint8_t addr; /* I2C address */ uint16_t config; /* INA226 config shadow */ int32_t shunt_resistor_value; /* micro-ohms, max 2.15 kohms */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* I2C Helpers */ static int ina226_write16(FAR struct ina226_dev_s *priv, uint8_t regaddr, FAR uint16_t regvalue); static int ina226_read16(FAR struct ina226_dev_s *priv, uint8_t regaddr, FAR uint16_t *regvalue); static int ina226_readpower(FAR struct ina226_dev_s *priv, FAR struct ina226_s *buffer); /* Character driver methods */ static int ina226_open(FAR struct file *filep); static int ina226_close(FAR struct file *filep); static ssize_t ina226_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t ina226_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int ina226_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_ina226fops = { ina226_open, ina226_close, ina226_read, ina226_write, NULL, ina226_ioctl, NULL #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ static int ina226_access(FAR struct ina226_dev_s *priv, uint8_t start_register_address, bool reading, FAR uint8_t *register_value, uint8_t data_length) { struct i2c_msg_s msg[I2C_NOSTARTSTOP_MSGS]; int ret; msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].frequency = CONFIG_INA226_I2C_FREQUENCY; msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].addr = priv->addr; msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].flags = 0; msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].buffer = &start_register_address; msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].length = 1; msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].addr = msg[I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX].addr; msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].flags = reading ? I2C_M_READ : 0; msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].buffer = register_value; msg[I2C_NOSTARTSTOP_DATA_MSG_INDEX].length = data_length; ret = I2C_TRANSFER(priv->i2c, msg, I2C_NOSTARTSTOP_MSGS); sninfo("start_register_address: " "0x%02X data_length: %d register_value: 0x%02x (0x%04x) ret: %d\n", start_register_address, data_length, *register_value, *((FAR uint16_t *)register_value), ret); return ret; } static int ina226_read16(FAR struct ina226_dev_s *priv, uint8_t regaddr, FAR uint16_t *regvalue) { uint8_t buf[2]; int ret = ina226_access(priv, regaddr, true, buf, 2); if (ret == 0) { *regvalue = ((uint16_t)buf[0] << 8) | (uint16_t)buf[1]; } return ret; } static int ina226_write16(FAR struct ina226_dev_s *priv, uint8_t regaddr, FAR uint16_t regvalue) { uint8_t buf[2]; int ret; buf[0] = (regvalue >> 8) & 0xff; buf[1] = regvalue & 0xff; ret = ina226_access(priv, regaddr, false, buf, 2); return ret; } /**************************************************************************** * Name: ina226_readpower * * Description: * Read the current and voltage register with special scaling * ****************************************************************************/ static int ina226_readpower(FAR struct ina226_dev_s *priv, FAR struct ina226_s *buffer) { uint16_t reg; int64_t tmp; int ret; /* Read the raw bus voltage */ ret = ina226_read16(priv, INA226_REG_BUS_VOLTAGE, ®); if (ret < 0) { snerr("ERROR: ina226_read16 failed: %d\n", ret); return ret; } /* Convert register value to bus voltage */ buffer->voltage = ((uint32_t)reg) * BV_LSB; /* 1 LSB 1,25mV */ /* Read the raw shunt voltage */ ret = ina226_read16(priv, INA226_REG_SHUNT_VOLTAGE, ®); if (ret < 0) { snerr("ERROR: ina226_read16 failed: %d\n", ret); return ret; } tmp = ((int64_t)(int16_t)reg); /* Convert shunt voltage to current across the shunt resistor. * I(uA) = U(uV)/R(ohms) * = U(uV)/(R(uohms)/1000000) * = U(uV) * 1000000 / R(uohms) * * U(uV) = tmp*2,5 * * We use a temporary 64-bit accumulator to avoid overflows. */ tmp = tmp * 2500000LL; tmp = tmp / (int64_t)priv->shunt_resistor_value; buffer->current = (int32_t)tmp; return OK; } /**************************************************************************** * Name: ina226_open * * Description: * This function is called whenever the INA226 device is opened. * ****************************************************************************/ static int ina226_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct ina226_dev_s *priv = inode->i_private; return ina226_write16(priv, INA226_REG_CONFIG, priv->config | INA226_CONFIG_MODE_SBCONT); } /**************************************************************************** * Name: ina226_close * * Description: * This routine is called when the INA226 device is closed. * ****************************************************************************/ static int ina226_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct ina226_dev_s *priv = inode->i_private; return ina226_write16(priv, INA226_REG_CONFIG, priv->config | INA226_CONFIG_MODE_PWRDOWN); } /**************************************************************************** * Name: ina226_read ****************************************************************************/ static ssize_t ina226_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct ina226_dev_s *priv = inode->i_private; FAR struct ina226_s *ptr; ssize_t nsamples; int i; int ret; /* How many samples were requested to get? */ nsamples = buflen / sizeof(struct ina226_s); ptr = (FAR struct ina226_s *)buffer; sninfo("buflen: %d nsamples: %d\n", buflen, nsamples); /* Get the requested number of samples */ for (i = 0; i < nsamples; i++) { struct ina226_s pwr; /* Read the next struct ina226_s power value */ ret = ina226_readpower(priv, &pwr); if (ret < 0) { snerr("ERROR: ina226_readpower failed: %d\n", ret); return (ssize_t)ret; } /* Save the power value in the user buffer */ *ptr++ = pwr; } return nsamples * sizeof(struct ina226_s); } /**************************************************************************** * Name: ina226_write ****************************************************************************/ static ssize_t ina226_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Name: ina226_ioctl ****************************************************************************/ static int ina226_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { return -ENOTTY; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: ina226_register * * Description: * Register the INA226 character device as 'devpath' * * Input Parameters: * devpath - The full path to the driver to register. E.g., "/dev/pwrmntr0" * i2c - An instance of the I2C interface to use to communicate with INA226 * addr - The I2C address of the INA226. * shuntval - the shunt resistor value in micro-ohms. * config - a combination of the constants defined earlier in this file. * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int ina226_register(FAR const char *devpath, FAR struct i2c_master_s *i2c, uint8_t addr, int32_t shuntval, uint16_t config) { FAR struct ina226_dev_s *priv; int ret = 0; /* Sanity check */ DEBUGASSERT(i2c != NULL); /* Initialize the ina226 device structure */ priv = (FAR struct ina226_dev_s *)kmm_malloc(sizeof(struct ina226_dev_s)); if (priv == NULL) { snerr("ERROR: Failed to allocate instance\n"); return -ENOMEM; } priv->i2c = i2c; priv->addr = addr; priv->shunt_resistor_value = shuntval; /* Save the config (except opmode) */ priv->config = config & ~INA226_CONFIG_MODE_MASK; /* Apply config, keep chip switched off */ ret = ina226_write16(priv, INA226_REG_CONFIG, priv->config | INA226_CONFIG_MODE_PWRDOWN); if (ret < 0) { snerr("ERROR: Failed to apply config: %d\n", ret); goto errout; } /* Register the character driver */ ret = register_driver(devpath, &g_ina226fops, 0666, priv); if (ret < 0) { snerr("ERROR: Failed to register driver: %d\n", ret); goto errout; } sninfo("(addr=0x%02x) registered at %s\n", priv->addr, devpath); return ret; errout: kmm_free(priv); return ret; }