116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
/* sensor_mcp9808.c - Driver for MCP9808 temperature sensor */
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/*
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* Copyright (c) 2016 Intel Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <errno.h>
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#include <kernel.h>
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#include <i2c.h>
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#include <init.h>
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#include <misc/byteorder.h>
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#include <misc/__assert.h>
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#include "mcp9808.h"
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int mcp9808_reg_read(struct mcp9808_data *data, uint8_t reg, uint16_t *val)
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{
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struct i2c_msg msgs[2] = {
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{
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.buf = ®,
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.len = 1,
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.flags = I2C_MSG_WRITE | I2C_MSG_RESTART,
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},
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{
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.buf = (uint8_t *)val,
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.len = 2,
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.flags = I2C_MSG_READ | I2C_MSG_STOP,
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},
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};
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if (i2c_transfer(data->i2c_master, msgs, 2, data->i2c_slave_addr)
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< 0) {
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return -EIO;
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}
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*val = sys_be16_to_cpu(*val);
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return 0;
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}
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static int mcp9808_sample_fetch(struct device *dev, enum sensor_channel chan)
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{
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struct mcp9808_data *data = dev->driver_data;
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL || chan == SENSOR_CHAN_TEMP);
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return mcp9808_reg_read(data, MCP9808_REG_TEMP_AMB, &data->reg_val);
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}
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static int mcp9808_channel_get(struct device *dev,
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enum sensor_channel chan,
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struct sensor_value *val)
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{
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struct mcp9808_data *data = dev->driver_data;
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_TEMP);
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val->type = SENSOR_VALUE_TYPE_INT_PLUS_MICRO;
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val->val1 = (data->reg_val & MCP9808_TEMP_INT_MASK) >>
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MCP9808_TEMP_INT_SHIFT;
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val->val2 = (data->reg_val & MCP9808_TEMP_FRAC_MASK) * 62500;
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if (data->reg_val & MCP9808_SIGN_BIT) {
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val->val1 -= 256;
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}
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return 0;
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}
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static const struct sensor_driver_api mcp9808_api_funcs = {
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.sample_fetch = mcp9808_sample_fetch,
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.channel_get = mcp9808_channel_get,
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.attr_set = mcp9808_attr_set,
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.trigger_set = mcp9808_trigger_set,
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};
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int mcp9808_init(struct device *dev)
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{
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struct mcp9808_data *data = dev->driver_data;
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data->i2c_master = device_get_binding(CONFIG_MCP9808_I2C_DEV_NAME);
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if (!data->i2c_master) {
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SYS_LOG_DBG("mcp9808: i2c master not found: %s",
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CONFIG_MCP9808_I2C_DEV_NAME);
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return -EINVAL;
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}
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data->i2c_slave_addr = CONFIG_MCP9808_I2C_ADDR;
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mcp9808_setup_interrupt(dev);
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dev->driver_api = &mcp9808_api_funcs;
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return 0;
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}
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struct mcp9808_data mcp9808_data;
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DEVICE_INIT(mcp9808, CONFIG_MCP9808_DEV_NAME, mcp9808_init, &mcp9808_data,
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NULL, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY);
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