/**************************************************************************** * drivers/sensors/ina219.c * Character driver for the INA219 Power Sensor * * Copyright (C) 2017 Sebastien Lorquet. All rights reserved. * Author: Sebastien Lorquet * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #if !defined(CONFIG_I2C) # error i2c support required #endif #define INA219_REG_CONFIG 0 /* See below */ #define INA219_REG_SHUNT_VOLTAGE 1 /* Shunt voltage in 10 uV units */ #define INA219_REG_BUS_VOLTAGE 2 /* Bus votlage in 4 mV units */ #define INA219_REG_POWER 3 /* Requires prior calibration */ #define INA219_REG_CURRENT 4 /* Requires prior calibration */ #define INA219_REG_CALIBRATION 5 /* Calibration value to compute current */ /* Operating modes - not controllable by user */ #define INA219_CONFIG_OPMODE_SHIFT 0 #define INA219_CONFIG_OPMODE_MASK (7 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_PWRDOWN (0 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_STRIG (1 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_BTRIG (2 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_SBTRIG (3 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_OFF (4 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_SCONT (5 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_BCONT (6 << INA219_CONFIG_OPMODE_SHIFT) #define INA219_CONFIG_OPMODE_SBCONT (7 << INA219_CONFIG_OPMODE_SHIFT) #ifndef CONFIG_INA219_I2C_FREQUENCY # define CONFIG_INA219_I2C_FREQUENCY 400000 #endif #define I2C_NOSTARTSTOP_MSGS 2 #define I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX 0 #define I2C_NOSTARTSTOP_DATA_MSG_INDEX 1 /**************************************************************************** * Private Types ****************************************************************************/ struct ina219_dev_s { FAR struct i2c_master_s *i2c; /* I2C interface */ uint8_t addr; /* I2C address */ uint16_t config; /* INA 219 config shadow */ int32_t shunt_resistor_value; /* micro-ohms, max 2.15 kohms */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* I2C Helpers */ static int ina219_write16(FAR struct ina219_dev_s *priv, uint8_t regaddr, FAR uint16_t regvalue); static int ina219_read16(FAR struct ina219_dev_s *priv, uint8_t regaddr, FAR uint16_t *regvalue); static int ina219_readpower(FAR struct ina219_dev_s *priv, FAR struct ina219_s *buffer); /* Character driver methods */ static int ina219_open(FAR struct file *filep); static int ina219_close(FAR struct file *filep); static ssize_t ina219_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t ina219_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int ina219_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_ina219fops = { ina219_open, ina219_close, ina219_read, ina219_write, NULL, ina219_ioctl, NULL #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ static int ina219_access(FAR struct ina219_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_INA219_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 ina219_read16(FAR struct ina219_dev_s *priv, uint8_t regaddr, FAR uint16_t *regvalue) { uint8_t buf[2]; int ret = ina219_access(priv, regaddr, true, buf, 2); if (ret == 0) { *regvalue = ((uint16_t)buf[0] << 8) | (uint16_t)buf[1]; } return ret; } static int ina219_write16(FAR struct ina219_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 = ina219_access(priv, regaddr, false, buf, 2); return ret; } /**************************************************************************** * Name: ina219_readpower * * Description: * Read the current and voltage register with special scaling * ****************************************************************************/ static int ina219_readpower(FAR struct ina219_dev_s *priv, FAR struct ina219_s *buffer) { uint16_t reg; int64_t tmp; int ret; /* Read the raw bus voltage */ ret = ina219_read16(priv, INA219_REG_BUS_VOLTAGE, ®); if (ret < 0) { snerr("ERROR: ina219_read16 failed: %d\n", ret); return ret; } /* Convert register value to bus voltage */ reg >>= 3; /* 3 LSB of reg contains status bits */ buffer->voltage = ((uint32_t)reg) * 4000LU; /* Read the raw shunt voltage */ ret = ina219_read16(priv, INA219_REG_SHUNT_VOLTAGE, ®); if (ret < 0) { snerr("ERROR: ina219_read16 failed: %d\n", ret); return ret; } /* Convert register value to shunt voltage */ tmp = ((int64_t)(int16_t)reg) * 10LL; /* micro volts across shunt */ /* 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) * We use a temporary 64-bit accumulator to avoid overflows. */ tmp = tmp * 1000000LL; tmp = tmp / (int64_t)priv->shunt_resistor_value; buffer->current = (int32_t)tmp; sninfo("Voltage: %u uV, Current: %d uA\n", buffer->voltage, buffer->current); return OK; } /**************************************************************************** * Name: ina219_open * * Description: * This function is called whenever the INA219 device is opened. * ****************************************************************************/ static int ina219_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct ina219_dev_s *priv = inode->i_private; return ina219_write16(priv, INA219_REG_CONFIG, priv->config | INA219_CONFIG_OPMODE_SBCONT); } /**************************************************************************** * Name: ina219_close * * Description: * This routine is called when the INA219 device is closed. * ****************************************************************************/ static int ina219_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct ina219_dev_s *priv = inode->i_private; return ina219_write16(priv, INA219_REG_CONFIG, priv->config | INA219_CONFIG_OPMODE_OFF); } /**************************************************************************** * Name: ina219_read ****************************************************************************/ static ssize_t ina219_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct ina219_dev_s *priv = inode->i_private; FAR struct ina219_s *ptr; ssize_t nsamples; int i; int ret; /* How many samples were requested to get? */ nsamples = buflen / sizeof(struct ina219_s); ptr = (FAR struct ina219_s *)buffer; sninfo("buflen: %d nsamples: %d\n", buflen, nsamples); /* Get the requested number of samples */ for (i = 0; i < nsamples; i++) { struct ina219_s pwr; /* Read the next struct ina219_s power value */ ret = ina219_readpower(priv, &pwr); if (ret < 0) { snerr("ERROR: ina219_readpower failed: %d\n", ret); return (ssize_t)ret; } /* Save the temperature value in the user buffer */ *ptr++ = pwr; } return nsamples * sizeof(struct ina219_s); } /**************************************************************************** * Name: ina219_write ****************************************************************************/ static ssize_t ina219_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Name: ina219_ioctl ****************************************************************************/ static int ina219_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { return -ENOTTY; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: ina219_register * * Description: * Register the INA219 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 INA219 * addr - The I2C address of the INA219. * shuntval - the shunt resistor value in micro-ohms. * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int ina219_register(FAR const char *devpath, FAR struct i2c_master_s *i2c, uint8_t addr, int32_t shuntval, uint16_t config) { FAR struct ina219_dev_s *priv; int ret = 0; /* Sanity check */ DEBUGASSERT(i2c != NULL); /* Initialize the ina219 device structure */ priv = (FAR struct ina219_dev_s *)kmm_malloc(sizeof(struct ina219_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 & ~INA219_CONFIG_OPMODE_MASK; /* Apply config, keep chip switched off */ ret = ina219_write16(priv, INA219_REG_CONFIG, priv->config | INA219_CONFIG_OPMODE_OFF); if (ret < 0) { snerr("ERROR: Failed to apply config: %d\n", ret); goto errout; } /* Register the character driver */ ret = register_driver(devpath, &g_ina219fops, 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; }