138 lines
3.0 KiB
C
138 lines
3.0 KiB
C
/* mpr.c - Driver for Honeywell MPR pressure sensor series */
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/*
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* Copyright (c) 2020 Sven Herrmann
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT honeywell_mpr
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#include <errno.h>
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#include <kernel.h>
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#include <sys/__assert.h>
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#include <drivers/sensor.h>
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#include <drivers/i2c.h>
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#include <sys/byteorder.h>
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#include <init.h>
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#include <logging/log.h>
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#include "mpr.h"
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#include "mpr_configuration.h"
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LOG_MODULE_REGISTER(MPR, CONFIG_SENSOR_LOG_LEVEL);
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static int mpr_init(struct device *dev)
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{
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struct mpr_data *data = dev->driver_data;
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const struct mpr_config *cfg = dev->config_info;
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data->i2c_master = device_get_binding(cfg->i2c_bus);
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if (!data->i2c_master) {
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LOG_ERR("mpr: i2c master not found: %s", cfg->i2c_bus);
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return -EINVAL;
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}
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return 0;
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}
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static int mpr_read_reg(struct device *dev)
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{
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struct mpr_data *data = dev->driver_data;
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const struct mpr_config *cfg = dev->config_info;
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u8_t write_buf[] = { MPR_OUTPUT_MEASUREMENT_COMMAND, 0x00, 0x00 };
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u8_t read_buf[4] = { 0x0 };
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int rc = i2c_write(data->i2c_master, write_buf, sizeof(write_buf),
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cfg->i2c_addr);
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if (rc < 0) {
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return rc;
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}
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u8_t retries = MPR_REG_READ_MAX_RETRIES;
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for (; retries > 0; retries--) {
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k_sleep(K_MSEC(MPR_REG_READ_DATA_CONV_DELAY_MS));
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rc = i2c_read(data->i2c_master, read_buf, sizeof(read_buf),
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cfg->i2c_addr);
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if (rc < 0) {
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return rc;
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}
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if (!(*read_buf & MPR_STATUS_MASK_POWER_ON)
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|| (*read_buf & MPR_STATUS_MASK_INTEGRITY_TEST_FAILED)
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|| (*read_buf & MPR_STATUS_MASK_MATH_SATURATION)) {
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return -EIO;
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}
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if (!(*read_buf & MPR_STATUS_MASK_BUSY)) {
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break;
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}
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}
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if (retries == 0) {
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return -EIO;
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}
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data->reg_val = (read_buf[1] << 16)
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| (read_buf[2] << 8)
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| read_buf[3];
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return 0;
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}
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/* (reg_value - out_min) * (p_max - p_min)
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* pressure = --------------------------------------- + p_min
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* out_max - out_min
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*
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* returns pressure [kPa] * 10^6
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*/
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static inline void mpr_convert_reg(const u32_t *reg, s64_t *value)
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{
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*value = (*reg - MPR_OUTPUT_MIN) * (MPR_P_MAX - MPR_P_MIN);
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*value *= MPR_CONVERSION_FACTOR;
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*value /= MPR_OUTPUT_RANGE;
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*value += MPR_P_MIN;
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}
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static int mpr_sample_fetch(struct device *dev, enum sensor_channel chan)
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{
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL || chan == SENSOR_CHAN_PRESS);
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return mpr_read_reg(dev);
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}
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static int mpr_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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const struct mpr_data *data = dev->driver_data;
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_PRESS);
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s64_t value;
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mpr_convert_reg(&data->reg_val, &value);
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val->val1 = value / 1000000;
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val->val2 = value % 1000000;
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return 0;
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}
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static const struct sensor_driver_api mpr_api_funcs = {
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.sample_fetch = mpr_sample_fetch,
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.channel_get = mpr_channel_get,
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};
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static struct mpr_data mpr_data;
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static const struct mpr_config mpr_cfg = {
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.i2c_bus = DT_INST_BUS_LABEL(0),
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.i2c_addr = DT_INST_REG_ADDR(0),
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};
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DEVICE_AND_API_INIT(mpr, DT_INST_LABEL(0), mpr_init, &mpr_data,
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&mpr_cfg, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,
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&mpr_api_funcs);
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