/**************************************************************************** * drivers/sensors/ltc4151.c * Character driver for the LTC 4151 Power Sensor * * Copyright (C) 2017 Giorgio Groß. All rights reserved. * Author: Giorgio Groß * * 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 #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 int ltc4151_open(FAR struct file *filep); static int ltc4151_close(FAR struct file *filep); 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); static int ltc4151_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_ltc4151fops = { ltc4151_open, ltc4151_close, ltc4151_read, ltc4151_write, NULL, ltc4151_ioctl, NULL #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL #endif }; /**************************************************************************** * 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_open * * Description: * This function is called whenever the LTC4151 device is opened. * ****************************************************************************/ static int ltc4151_open(FAR struct file *filep) { return OK; } /**************************************************************************** * Name: ltc4151_close * * Description: * This routine is called when the LTC4151 device is closed. * ****************************************************************************/ static int ltc4151_close(FAR struct file *filep) { 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; } /**************************************************************************** * Name: ltc4151_ioctl ****************************************************************************/ static int ltc4151_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { return -ENOTTY; } /**************************************************************************** * 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 */