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/* * Copyright (c) 2016 Intel Corporation * * SPDX-License-Identifier: Apache-2.0 */ #include <adc.h> #include <device.h> #include <math.h> #include <sensor.h> #include <zephyr.h> #define SYS_LOG_DOMAIN "GROVE_LIGHT_SENSOR" #define SYS_LOG_LEVEL CONFIG_SYS_LOG_GROVE_LEVEL #include <logging/sys_log.h> struct gls_data { struct device *adc; struct adc_seq_entry sample; struct adc_seq_table adc_table; uint8_t adc_buffer[4]; }; static int gls_sample_fetch(struct device *dev, enum sensor_channel chan) { struct gls_data *drv_data = dev->driver_data; return adc_read(drv_data->adc, &drv_data->adc_table); } static int gls_channel_get(struct device *dev, enum sensor_channel chan, struct sensor_value *val) { struct gls_data *drv_data = dev->driver_data; uint16_t analog_val; double ldr_val, dval; /* rescale sample from 12bit (Zephyr) to 10bit (Grove) */ analog_val = ((uint16_t)drv_data->adc_buffer[1] << 8) | drv_data->adc_buffer[0]; analog_val = analog_val >> 2; /* * The formula for converting the analog value to lux is taken from * the UPM project: * https://github.com/intel-iot-devkit/upm/blob/master/src/grove/grove.cxx#L161 */ ldr_val = (1023.0 - analog_val) * 10.0 / analog_val; dval = 10000.0 / pow(ldr_val * 15.0, 4.0/3.0); val->val1 = (int32_t)dval; val->val2 = ((int32_t)(dval * 1000000)) % 1000000; return 0; } static const struct sensor_driver_api gls_api = { .sample_fetch = &gls_sample_fetch, .channel_get = &gls_channel_get, }; static int gls_init(struct device *dev) { struct gls_data *drv_data = dev->driver_data; drv_data->adc = device_get_binding(CONFIG_GROVE_LIGHT_SENSOR_ADC_DEV_NAME); if (drv_data->adc == NULL) { SYS_LOG_ERR("Failed to get ADC device."); return -EINVAL; } drv_data->sample.sampling_delay = 12; drv_data->sample.channel_id = CONFIG_GROVE_LIGHT_SENSOR_ADC_CHANNEL; drv_data->sample.buffer = drv_data->adc_buffer; drv_data->sample.buffer_length = 4; drv_data->adc_table.entries = &drv_data->sample; drv_data->adc_table.num_entries = 1; adc_enable(drv_data->adc); dev->driver_api = &gls_api; return 0; } static struct gls_data gls_data; DEVICE_INIT(gls_dev, CONFIG_GROVE_LIGHT_SENSOR_NAME, &gls_init, &gls_data, NULL, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY); |