1 /*
2 * Copyright (c) 2016 Intel Corporation
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #define DT_DRV_COMPAT seeed_grove_light
8
9 #include <zephyr/drivers/adc.h>
10 #include <zephyr/device.h>
11 #include <zephyr/devicetree.h>
12 #include <math.h>
13 #include <zephyr/drivers/sensor.h>
14 #include <zephyr/kernel.h>
15 #include <zephyr/logging/log.h>
16
17 LOG_MODULE_REGISTER(grove_light, CONFIG_SENSOR_LOG_LEVEL);
18
19 /* The effect of gain and reference voltage must cancel. */
20 #ifdef CONFIG_ADC_NRFX_SAADC
21 #define GROVE_GAIN ADC_GAIN_1_4
22 #define GROVE_REF ADC_REF_VDD_1_4
23 #define GROVE_RESOLUTION 12
24 #else
25 #define GROVE_GAIN ADC_GAIN_1
26 #define GROVE_REF ADC_REF_VDD_1
27 #define GROVE_RESOLUTION 12
28 #endif
29
30
31 struct gls_data {
32 const struct device *adc;
33 struct adc_channel_cfg ch_cfg;
34 uint16_t raw;
35 };
36
37 struct gls_config {
38 const struct device *adc;
39 uint8_t adc_channel;
40 };
41
42 static struct adc_sequence_options options = {
43 .interval_us = 12,
44 .extra_samplings = 0,
45 };
46
47 static struct adc_sequence adc_table = {
48 .options = &options,
49 };
50
gls_sample_fetch(const struct device * dev,enum sensor_channel chan)51 static int gls_sample_fetch(const struct device *dev,
52 enum sensor_channel chan)
53 {
54 const struct gls_config *cfg = dev->config;
55
56 return adc_read(cfg->adc, &adc_table);
57 }
58
gls_channel_get(const struct device * dev,enum sensor_channel chan,struct sensor_value * val)59 static int gls_channel_get(const struct device *dev,
60 enum sensor_channel chan,
61 struct sensor_value *val)
62 {
63 struct gls_data *drv_data = dev->data;
64 uint16_t analog_val = drv_data->raw;
65 double ldr_val, dval;
66
67 /*
68 * The formula for converting the analog value to lux is taken from
69 * the UPM project:
70 * https://github.com/intel-iot-devkit/upm/blob/master/src/grove/grove.cxx#L161
71 */
72 ldr_val = (BIT(GROVE_RESOLUTION) - 1.0 - analog_val) * 10.0 / analog_val;
73 dval = 10000.0 / pow(ldr_val * 15.0, 4.0/3.0);
74
75 val->val1 = (int32_t)dval;
76 val->val2 = ((int32_t)(dval * 1000000)) % 1000000;
77
78 return 0;
79 }
80
81 static const struct sensor_driver_api gls_api = {
82 .sample_fetch = &gls_sample_fetch,
83 .channel_get = &gls_channel_get,
84 };
85
gls_init(const struct device * dev)86 static int gls_init(const struct device *dev)
87 {
88 struct gls_data *drv_data = dev->data;
89 const struct gls_config *cfg = dev->config;
90
91 if (!device_is_ready(cfg->adc)) {
92 LOG_ERR("ADC device is not ready.");
93 return -EINVAL;
94 }
95
96 /*Change following parameters according to board if necessary*/
97 drv_data->ch_cfg = (struct adc_channel_cfg){
98 .gain = GROVE_GAIN,
99 .reference = GROVE_REF,
100 .acquisition_time = ADC_ACQ_TIME_DEFAULT,
101 .channel_id = cfg->adc_channel,
102 #ifdef CONFIG_ADC_NRFX_SAADC
103 .input_positive = SAADC_CH_PSELP_PSELP_AnalogInput0 + cfg->adc_channel,
104 #endif
105 };
106 adc_table.buffer = &drv_data->raw;
107 adc_table.buffer_size = sizeof(drv_data->raw);
108 adc_table.resolution = GROVE_RESOLUTION;
109 adc_table.channels = BIT(cfg->adc_channel);
110
111 adc_channel_setup(cfg->adc, &drv_data->ch_cfg);
112
113 return 0;
114 }
115
116 #define GLS_DEFINE(inst) \
117 static struct gls_data gls_data_##inst; \
118 \
119 static const struct gls_config gls_cfg_##inst = { \
120 .adc = DEVICE_DT_GET(DT_INST_IO_CHANNELS_CTLR(inst)), \
121 .adc_channel = DT_INST_IO_CHANNELS_INPUT(inst), \
122 }; \
123 \
124 SENSOR_DEVICE_DT_INST_DEFINE(inst, &gls_init, NULL, \
125 &gls_data_##inst, &gls_cfg_##inst, POST_KERNEL, \
126 CONFIG_SENSOR_INIT_PRIORITY, &gls_api); \
127
128 DT_INST_FOREACH_STATUS_OKAY(GLS_DEFINE)
129
