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/*
* Copyright (c) 2016 Intel Corporation
*
* Licensed 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.
*/
#include <i2c.h>
#include <init.h>
#include <misc/__assert.h>
#include <misc/byteorder.h>
#include <sensor.h>
#include <string.h>
#include "hts221.h"
static int hts221_channel_get(struct device *dev,
enum sensor_channel chan,
struct sensor_value *val)
{
struct hts221_data *drv_data = dev->driver_data;
int32_t conv_val;
__ASSERT_NO_MSG(chan == SENSOR_CHAN_TEMP || SENSOR_CHAN_HUMIDITY);
/*
* see "Interpreting humidity and temperature readings" document
* for more details
*/
if (chan == SENSOR_CHAN_TEMP) {
conv_val = (int32_t)(drv_data->t1_degc_x8 -
drv_data->t0_degc_x8) *
(drv_data->t_sample - drv_data->t0_out) /
(drv_data->t1_out - drv_data->t0_out) +
drv_data->t0_degc_x8;
/* convert temperature x8 to degrees Celsius */
val->val1 = conv_val / 8;
val->val2 = (conv_val % 8) * (1000000 / 8);
} else { /* SENSOR_CHAN_HUMIDITY */
conv_val = (int32_t)(drv_data->h1_rh_x2 - drv_data->h0_rh_x2) *
(drv_data->rh_sample - drv_data->h0_t0_out) /
(drv_data->h1_t0_out - drv_data->h0_t0_out) +
drv_data->h0_rh_x2;
/* convert humidity x2 to mili-percent */
val->val1 = conv_val * 500;
val->val2 = 0;
}
return 0;
}
static int hts221_sample_fetch(struct device *dev, enum sensor_channel chan)
{
struct hts221_data *drv_data = dev->driver_data;
uint8_t buf[4];
__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
if (i2c_burst_read(drv_data->i2c, HTS221_I2C_ADDR,
HTS221_REG_DATA_START | HTS221_AUTOINCREMENT_ADDR,
buf, 4) < 0) {
SYS_LOG_ERR("Failed to fetch data sample.");
return -EIO;
}
drv_data->rh_sample = sys_le16_to_cpu(buf[0] | (buf[1] << 8));
drv_data->t_sample = sys_le16_to_cpu(buf[2] | (buf[3] << 8));
return 0;
}
static int hts221_read_conversion_data(struct hts221_data *drv_data)
{
uint8_t buf[16];
if (i2c_burst_read(drv_data->i2c, HTS221_I2C_ADDR,
HTS221_REG_CONVERSION_START |
HTS221_AUTOINCREMENT_ADDR, buf, 16) < 0) {
SYS_LOG_ERR("Failed to read conversion data.");
return -EIO;
}
drv_data->h0_rh_x2 = buf[0];
drv_data->h1_rh_x2 = buf[1];
drv_data->t0_degc_x8 = sys_le16_to_cpu(buf[2] | ((buf[5] & 0x3) << 8));
drv_data->t1_degc_x8 = sys_le16_to_cpu(buf[3] | ((buf[5] & 0xC) << 6));
drv_data->h0_t0_out = sys_le16_to_cpu(buf[6] | (buf[7] << 8));
drv_data->h1_t0_out = sys_le16_to_cpu(buf[10] | (buf[11] << 8));
drv_data->t0_out = sys_le16_to_cpu(buf[12] | (buf[13] << 8));
drv_data->t1_out = sys_le16_to_cpu(buf[14] | (buf[15] << 8));
return 0;
}
static const struct sensor_driver_api hts221_driver_api = {
#if CONFIG_HTS221_TRIGGER
.trigger_set = hts221_trigger_set,
#endif
.sample_fetch = hts221_sample_fetch,
.channel_get = hts221_channel_get,
};
int hts221_init(struct device *dev)
{
struct hts221_data *drv_data = dev->driver_data;
uint8_t id, idx;
drv_data->i2c = device_get_binding(CONFIG_HTS221_I2C_MASTER_DEV_NAME);
if (drv_data->i2c == NULL) {
SYS_LOG_ERR("Could not get pointer to %s device.",
CONFIG_HTS221_I2C_MASTER_DEV_NAME);
return -EINVAL;
}
/* check chip ID */
if (i2c_reg_read_byte(drv_data->i2c, HTS221_I2C_ADDR,
HTS221_REG_WHO_AM_I, &id) < 0) {
SYS_LOG_ERR("Failed to read chip ID.");
return -EIO;
}
if (id != HTS221_CHIP_ID) {
SYS_LOG_ERR("Invalid chip ID.");
return -EINVAL;
}
/* check if CONFIG_HTS221_ODR is valid */
for (idx = 0; idx < ARRAY_SIZE(hts221_odr_strings); idx++) {
if (!strcmp(hts221_odr_strings[idx], CONFIG_HTS221_ODR)) {
break;
}
}
if (idx == ARRAY_SIZE(hts221_odr_strings)) {
SYS_LOG_ERR("Invalid ODR value.");
return -EINVAL;
}
if (i2c_reg_write_byte(drv_data->i2c, HTS221_I2C_ADDR, HTS221_REG_CTRL1,
(idx + 1) << HTS221_ODR_SHIFT | HTS221_BDU_BIT |
HTS221_PD_BIT) < 0) {
SYS_LOG_ERR("Failed to configure chip.");
return -EIO;
}
if (hts221_read_conversion_data(drv_data) < 0) {
SYS_LOG_ERR("Failed to read conversion data.");
return -EINVAL;
}
#ifdef CONFIG_HTS221_TRIGGER
if (hts221_init_interrupt(dev) < 0) {
SYS_LOG_ERR("Failed to initialize interrupt.");
return -EIO;
}
#endif
dev->driver_api = &hts221_driver_api;
return 0;
}
struct hts221_data hts221_driver;
DEVICE_INIT(hts221, CONFIG_HTS221_NAME, hts221_init, &hts221_driver,
NULL, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY);
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