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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 <device.h>
#include <i2c.h>
#include <sensor.h>
#include <misc/__assert.h>
#include "max44009.h"
static int max44009_reg_read(struct max44009_data *drv_data, uint8_t reg,
uint8_t *val, bool send_stop)
{
struct i2c_msg msgs[2] = {
{
.buf = ®,
.len = 1,
.flags = I2C_MSG_WRITE,
},
{
.buf = val,
.len = 1,
.flags = I2C_MSG_READ,
},
};
if (send_stop) {
msgs[1].flags |= I2C_MSG_STOP;
}
if (i2c_transfer(drv_data->i2c, msgs, 2, MAX44009_I2C_ADDRESS) != 0) {
return -EIO;
}
return 0;
}
static int max44009_reg_write(struct max44009_data *drv_data, uint8_t reg,
uint8_t val)
{
uint8_t tx_buf[2] = {reg, val};
return i2c_write(drv_data->i2c, tx_buf, sizeof(tx_buf),
MAX44009_I2C_ADDRESS);
}
static int max44009_reg_update(struct max44009_data *drv_data, uint8_t reg,
uint8_t mask, uint8_t val)
{
uint8_t old_val = 0;
uint8_t new_val = 0;
if (max44009_reg_read(drv_data, reg, &old_val, true) != 0) {
return -EIO;
}
new_val = old_val & ~mask;
new_val |= val & mask;
return max44009_reg_write(drv_data, reg, new_val);
}
static int max44009_attr_set(struct device *dev, enum sensor_channel chan,
enum sensor_attribute attr,
const struct sensor_value *val)
{
struct max44009_data *drv_data = dev->driver_data;
uint8_t value;
uint32_t cr;
if (chan != SENSOR_CHAN_LIGHT) {
return -ENOTSUP;
}
switch (attr) {
case SENSOR_ATTR_SAMPLING_FREQUENCY:
if (val->type != SENSOR_VALUE_TYPE_INT_PLUS_MICRO) {
return -ENOTSUP;
}
/* convert rate to mHz */
cr = val->val1 * 1000 + val->val2 / 1000;
/* the sensor supports 1.25Hz or continuous conversion */
switch (cr) {
case 1250:
value = 0;
break;
default:
value = MAX44009_CONTINUOUS_SAMPLING;
}
if (max44009_reg_update(drv_data, MAX44009_REG_CONFIG,
MAX44009_SAMPLING_CONTROL_BIT,
value) != 0) {
SYS_LOG_DBG("Failed to set attribute!");
return -EIO;
}
return 0;
default:
return -ENOTSUP;
}
return 0;
}
static int max44009_sample_fetch(struct device *dev, enum sensor_channel chan)
{
struct max44009_data *drv_data = dev->driver_data;
uint8_t val_h, val_l;
__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL || chan == SENSOR_CHAN_LIGHT);
drv_data->sample = 0;
if (max44009_reg_read(drv_data, MAX44009_REG_LUX_HIGH_BYTE, &val_h,
false) != 0) {
return -EIO;
}
if (max44009_reg_read(drv_data, MAX44009_REG_LUX_LOW_BYTE, &val_l,
true) != 0) {
return -EIO;
}
drv_data->sample = ((uint16_t)val_h) << 8;
drv_data->sample += val_l;
return 0;
}
static int max44009_channel_get(struct device *dev, enum sensor_channel chan,
struct sensor_value *val)
{
struct max44009_data *drv_data = dev->driver_data;
uint32_t uval;
if (chan != SENSOR_CHAN_LIGHT) {
return -ENOTSUP;
}
/**
* sample consists of 4 bits of exponent and 8 bits of mantissa
* bits 15 to 12 are exponent bits
* bits 11 to 8 and 3 to 0 are the mantissa bits
*/
uval = drv_data->sample;
uval = (uval & MAX44009_MANTISSA_LOW_NIBBLE_MASK) +
((uval & MAX44009_MANTISSA_HIGH_NIBBLE_MASK) >> 4);
uval = uval << (drv_data->sample >> MAX44009_SAMPLE_EXPONENT_SHIFT);
/* lux is the integer of sample output multiplied by 0.045. */
val->type = SENSOR_VALUE_TYPE_INT_PLUS_MICRO;
val->val1 = (uval * 45) / 1000;
val->val2 = ((uval * 45) % 1000) * 1000;
return 0;
}
static const struct sensor_driver_api max44009_driver_api = {
.attr_set = max44009_attr_set,
.sample_fetch = max44009_sample_fetch,
.channel_get = max44009_channel_get,
};
int max44009_init(struct device *dev)
{
struct max44009_data *drv_data = dev->driver_data;
drv_data->i2c = device_get_binding(CONFIG_MAX44009_I2C_DEV_NAME);
if (drv_data->i2c == NULL) {
SYS_LOG_DBG("Failed to get pointer to %s device!",
CONFIG_MAX44009_I2C_DEV_NAME);
return -EINVAL;
}
dev->driver_api = &max44009_driver_api;
return 0;
}
static struct max44009_data max44009_drv_data;
DEVICE_INIT(max44009, CONFIG_MAX44009_DRV_NAME, max44009_init,
&max44009_drv_data, NULL, POST_KERNEL,
CONFIG_SENSOR_INIT_PRIORITY);
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