/**************************************************************************** * drivers/sensors/mcp9844.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 #if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_MCP9844) /**************************************************************************** * Pre-process Definitions ****************************************************************************/ #ifndef CONFIG_MCP9844_I2C_FREQUENCY # define CONFIG_MCP9844_I2C_FREQUENCY 400000 #endif /**************************************************************************** * Private Types ****************************************************************************/ struct mcp9844_dev_s { FAR struct i2c_master_s *i2c; /* I2C interface */ uint8_t addr; /* I2C address */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* I2C helper functions */ static int mcp9844_read_u16(FAR struct mcp9844_dev_s *priv, uint8_t const regaddr, FAR uint16_t *value); static int mcp9844_write_u16(FAR struct mcp9844_dev_s *priv, uint8_t const regaddr, uint16_t const regval); /* Character driver methods */ static int mcp9844_open(FAR struct file *filep); static int mcp9844_close(FAR struct file *filep); static ssize_t mcp9844_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t mcp9844_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int mcp9844_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_mcp9844_fops = { mcp9844_open, mcp9844_close, mcp9844_read, mcp9844_write, NULL, mcp9844_ioctl, NULL }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: mcp9844_read_u16 * * Description: * Read a 16 bit valie from the MCP9844 at the address regaddr. * ****************************************************************************/ static int mcp9844_read_u16(FAR struct mcp9844_dev_s *priv, uint8_t const regaddr, FAR uint16_t *value) { struct i2c_config_s config; uint8_t buffer[2]; int ret = -1; /* Set up the I2C configuration */ config.frequency = CONFIG_MCP9844_I2C_FREQUENCY; config.address = priv->addr; config.addrlen = 7; /* Write the register address */ ret = i2c_write(priv->i2c, &config, ®addr, 1); if (ret < 0) { snerr ("i2c_write failed: %d\n", ret); return ret; } /* Restart and read 16-bits from the register */ ret = i2c_read(priv->i2c, &config, buffer, 2); if (ret < 0) { snerr ("i2c_read failed: %d\n", ret); return ret; } /* Copy the content of the buffer to the location of the uint16_t pointer */ *value = (((uint16_t)(buffer[0])) << 8) + ((uint16_t)(buffer[1])); sninfo("addr: %02x value: %08x ret: %d\n", regaddr, *value, ret); return OK; } /**************************************************************************** * Name: mcp9844_write_u16 * * Description: * Write to a 16-bit register of the MCP9844. * ****************************************************************************/ static int mcp9844_write_u16(FAR struct mcp9844_dev_s *priv, uint8_t const regaddr, uint16_t const regval) { struct i2c_config_s config; sninfo("addr: %02x value: %08x\n", regaddr, regval); /* Set up a 3 byte message to send */ uint8_t const BUFFER_SIZE = 3; uint8_t buffer[BUFFER_SIZE]; buffer[0] = regaddr; buffer[1] = (uint8_t)(regval >> 8); buffer[2] = (uint8_t)(regval); /* Set up the I2C configuration */ config.frequency = CONFIG_MCP9844_I2C_FREQUENCY; config.address = priv->addr; config.addrlen = 7; /* Write the register address followed by the data (no RESTART) */ return i2c_write(priv->i2c, &config, buffer, BUFFER_SIZE); } /**************************************************************************** * Name: mcp9844_open * * Description: * This function is called whenever the MCP9844 device is opened. * ****************************************************************************/ static int mcp9844_open(FAR struct file *filep) { return OK; } /**************************************************************************** * Name: mcp9844_close * * Description: * This routine is called when the MCP9844 device is closed. * ****************************************************************************/ static int mcp9844_close(FAR struct file *filep) { return OK; } /**************************************************************************** * Name: mcp9844_read ****************************************************************************/ static ssize_t mcp9844_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Name: mcp9844_write ****************************************************************************/ static ssize_t mcp9844_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Name: lm75_ioctl ****************************************************************************/ static int mcp9844_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode = filep->f_inode; FAR struct mcp9844_dev_s *priv = inode->i_private; int ret = OK; switch (cmd) { /* Read from the ambient temperature register. Arg: uint16_t* pointer */ case SNIOC_READTEMP: { FAR struct mcp9844_temp_arg_s *temp_result = (FAR struct mcp9844_temp_arg_s *)((uintptr_t)arg); DEBUGASSERT(temp_result != NULL); /* Read the ambient temperature value from the device */ uint16_t raw_temperature = 0; ret = mcp9844_read_u16(priv, MCP9844_TEMP_REG, &raw_temperature); /* Convert from the proprietary sensor temperature data * representation to a more user-friendly version. */ if (ret == OK) { /* Feed sensor data to entropy pool */ add_sensor_randomness(raw_temperature); /* BIT15 - 13 contain information if preset temperature values * have been exceeded or undercut. BIT12 is now not any longer * needed since we do have the sign information retrieved. * We do not need them for the temperature so those bits * need to be masked out. */ raw_temperature &= 0x0fff; /* 0x0fff = 0b 0000 1111 1111 1111 */ /* The post comma temperature value is encoded in BIT3 to * BIT0 */ temp_result->temp_post_comma = (uint8_t)(raw_temperature & 0x000f); /* The pre comma temperature value is encoded in BIT11 to * BIT4 */ temp_result->temp_pre_comma = (int8_t)(raw_temperature >> 4); } else { snerr("ERROR: ioctl::SNIOC_READTEMP - mcp9844_read_u16 failed" " - no temperature retrieved\n"); } } break; case SNIOC_SETRESOLUTION: { ret = mcp9844_write_u16(priv, MCP9844_RESO_REG, (uint16_t)(arg)); if (ret != OK) { snerr("ERROR: ioctl::SNIOC_SETRESOLUTION - mcp9844_write_u16" "failed - no resolution set\n"); } } break; case SNIOC_SHUTDOWN: { uint16_t config_reg; /* Perform a read-modify-write cycle on the config register */ ret = mcp9844_read_u16(priv, MCP9844_CONF_REG, &config_reg); if (ret == OK) { config_reg |= MCP9844_CONF_REG_SHDN; ret = mcp9844_write_u16(priv, MCP9844_CONF_REG, config_reg); if (ret != OK) { snerr("ERROR: ioctl::SNIOC_SHUTDOWN - " "mcp9844_write_u16 failed\n"); } } else { snerr("ERROR: ioctl::SNIOC_SHUTDOWN - " "mcp9844_read_u16 failed\n"); } } break; case SNIOC_POWERUP: { uint16_t config_reg; /* Perform a read-modify-write cycle on the config register */ ret = mcp9844_read_u16(priv, MCP9844_CONF_REG, &config_reg); if (ret == OK) { config_reg &= ~MCP9844_CONF_REG_SHDN; ret = mcp9844_write_u16(priv, MCP9844_CONF_REG, config_reg); if (ret != OK) { snerr("ERROR: ioctl::SNIOC_POWERUP - " "mcp9844_write_u16 failed\n"); } } else { snerr("ERROR: ioctl::SNIOC_POWERUP - " "mcp9844_read_u16 failed\n"); } } break; default: snerr("ERROR: Unrecognized cmd: %d\n", cmd); ret = -ENOTTY; break; } return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: mcp9844_register * * Description: * Register the MCP9844 character device as 'devpath' * * Input Parameters: * devpath - The full path to the driver to register. E.g., "/dev/temp0" * i2c - An instance of the I2C interface to use to communicate with * MCP9844 * addr - The I2C address of the MCP9844. * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int mcp9844_register(FAR const char *devpath, FAR struct i2c_master_s *i2c, uint8_t addr) { /* Sanity check */ DEBUGASSERT(i2c != NULL); /* Initialize the MCP9844 device structure */ FAR struct mcp9844_dev_s *priv = (FAR struct mcp9844_dev_s *)kmm_malloc(sizeof(struct mcp9844_dev_s)); if (priv == NULL) { snerr("ERROR: Failed to allocate instance\n"); return -ENOMEM; } priv->i2c = i2c; priv->addr = addr; /* Register the character driver */ int ret = register_driver(devpath, &g_mcp9844_fops, 0666, priv); if (ret < 0) { snerr("ERROR: Failed to register driver: %d\n", ret); kmm_free(priv); } return ret; } #endif /* CONFIG_I2C && CONFIG_LM75_I2C */