/**************************************************************************** * drivers/sensors/ltc4151.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 #include #include #if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_LTC4151) /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #ifndef CONFIG_LTC4151_I2C_FREQUENCY # define CONFIG_LTC4151_I2C_FREQUENCY 400000 #endif #define I2C_NOSTARTSTOP_MSGS 2 #define I2C_NOSTARTSTOP_ADDRESS_MSG_INDEX 0 #define I2C_NOSTARTSTOP_DATA_MSG_INDEX 1 /**************************************************************************** * Private ****************************************************************************/ struct ltc4151_dev_s { FAR struct i2c_master_s *i2c; /* I2C interface */ uint8_t addr; /* I2C address */ float shunt_resistor_value; /* [ohm] */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* I2C Helpers */ static int ltc4151_read16(FAR struct ltc4151_dev_s *priv, uint8_t regaddr, FAR uint16_t *regvalue); static int ltc4151_readpower(FAR struct ltc4151_dev_s *priv, FAR struct ltc4151_s *buffer); /* Character driver methods */ static ssize_t ltc4151_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t ltc4151_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_ltc4151fops = { NULL, /* open */ NULL, /* close */ ltc4151_read, /* read */ ltc4151_write, /* write */ }; /**************************************************************************** * Private Functions ****************************************************************************/ static int ltc4151_read_reg(FAR struct ltc4151_dev_s *priv, uint8_t start_register_address, 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_LTC4151_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 = I2C_M_READ; 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 ltc4151_read16(FAR struct ltc4151_dev_s *priv, uint8_t regaddr, FAR uint16_t *regvalue) { int ret = ltc4151_read_reg(priv, regaddr, (FAR uint8_t *)regvalue, sizeof(*regvalue)); /* Bytes are 8bit_msb.4bit_0.4bit_lsb = 16bit */ *regvalue = ((*regvalue & LTC4151_VALUE_MSB_MASK) << 4) | ((*regvalue & LTC4151_VALUE_LSB_MASK) >> 8); return ret; } /**************************************************************************** * Name: ltc4151_readpower * * Description: * Read the current and voltage register with special scaling * ****************************************************************************/ static int ltc4151_readpower(FAR struct ltc4151_dev_s *priv, FAR struct ltc4151_s *buffer) { float float_current; float float_voltage; uint16_t current_reg; uint16_t volt_reg; int ret; /* Read the raw temperature data (b16_t) */ ret = ltc4151_read16(priv, LTC4151_CURR_REG, ¤t_reg); if (ret < 0) { snerr("ERROR: ltc4151_read16 failed: %d\n", ret); return ret; } ret = ltc4151_read16(priv, LTC4151_VOLT_REG, &volt_reg); if (ret < 0) { snerr("ERROR: ltc4151_read16 failed: %d\n", ret); return ret; } /* Current is passed as delta voltage, to get the current divide it by the * used resistors resistance. * * float_current = register in 20 micro volt, shunt in ohm -> result in * milliampere */ float_current = (((float)current_reg) * 20.0 / (1000.0 * priv->shunt_resistor_value)); buffer->current = ftob16(float_current); sninfo("current_reg=0x%04x float_current=%d\n", current_reg, (int)float_current); /* fload_voltage = register in 25 micro volt -> result in volt */ float_voltage = ((float)volt_reg) * 25.0 / 1000.0; buffer->voltage = ftob16(float_voltage); sninfo("volt_reg=0x%04x float_voltage=%d\n", volt_reg, (int)float_voltage); return OK; } /**************************************************************************** * Name: ltc4151_read ****************************************************************************/ static ssize_t ltc4151_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct ltc4151_dev_s *priv = inode->i_private; FAR struct ltc4151_s *ptr; ssize_t nsamples; int i; int ret; /* How many samples were requested to get? */ nsamples = buflen / sizeof(struct ltc4151_s); ptr = (FAR struct ltc4151_s *)buffer; sninfo("buflen: %d nsamples: %d\n", buflen, nsamples); /* Get the requested number of samples */ for (i = 0; i < nsamples; i++) { struct ltc4151_s pwr; /* Read the next struct ltc4151_s power value */ ret = ltc4151_readpower(priv, &pwr); if (ret < 0) { snerr("ERROR: ltc4151_readtemp failed: %d\n", ret); return (ssize_t)ret; } /* Save the temperature value in the user buffer */ *ptr++ = pwr; } return nsamples * sizeof(struct ltc4151_s); } /**************************************************************************** * Name: ltc4151_write ****************************************************************************/ static ssize_t ltc4151_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: ltc4151_register * * Description: * Register the LTC4151 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 * LTC4151 * addr - The I2C address of the LTC4151. The base I2C address of the * LTC4151 is 0x6f. Bits 0-3 can be controlled to get 10 unique * addresses from 0x66 through 0x6f. * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int ltc4151_register(FAR const char *devpath, FAR struct i2c_master_s *i2c, uint8_t addr, float shunt_resistor_value) { FAR struct ltc4151_dev_s *priv; int ret; /* Sanity check */ DEBUGASSERT(i2c != NULL); DEBUGASSERT(addr == CONFIG_LTC4151_ADDR0 || addr == CONFIG_LTC4151_ADDR1 || addr == CONFIG_LTC4151_ADDR2 || addr == CONFIG_LTC4151_ADDR3 || addr == CONFIG_LTC4151_ADDR4 || addr == CONFIG_LTC4151_ADDR5 || addr == CONFIG_LTC4151_ADDR6 || addr == CONFIG_LTC4151_ADDR7 || addr == CONFIG_LTC4151_ADDR8 || addr == CONFIG_LTC4151_ADDR9); /* Initialize the ltc4151 device structure */ priv = (FAR struct ltc4151_dev_s *) kmm_malloc(sizeof(struct ltc4151_dev_s)); if (priv == NULL) { snerr("ERROR: Failed to allocate instance\n"); return -ENOMEM; } priv->i2c = i2c; priv->addr = addr; priv->shunt_resistor_value = shunt_resistor_value; /* Register the character driver */ ret = register_driver(devpath, &g_ltc4151fops, 0666, priv); if (ret < 0) { snerr("ERROR: Failed to register driver: %d\n", ret); kmm_free(priv); } sninfo("ltc4151 (addr=0x%02x) registered at %s\n", priv->addr, devpath); return ret; } #endif /* CONFIG_I2C && CONFIG_SENSORS_LTC4151 */