1 /*
2 * Copyright (c) 2023 FTP Technologies
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #define DT_DRV_COMPAT microchip_mcp970x
8
9 #include <zephyr/drivers/adc.h>
10 #include <zephyr/drivers/sensor.h>
11
12 #include <zephyr/logging/log.h>
13 LOG_MODULE_REGISTER(mcp970x, CONFIG_SENSOR_LOG_LEVEL);
14
15 enum ic_family {
16 FAMILY_MCP9700_9700A,
17 FAMILY_MCP9701_9701A
18 };
19
20 /* Milli degrees C per degree C */
21 #define MC_PER_C 1000
22
23 #define MV_AT_0C_MCP9700_9700A 500
24 #define MV_AT_0C_MCP9701_9701A 400
25
26 #define T_COEFF_MCP9700_9700A 10
27 #define T_COEFF_MCP9701_9701A 19.5
28
29 struct mcp970x_config {
30 struct adc_dt_spec adc;
31 enum ic_family family;
32 };
33
34 struct mcp970x_data {
35 struct adc_sequence sequence;
36 int16_t raw;
37 };
38
fetch(const struct device * dev,enum sensor_channel chan)39 static int fetch(const struct device *dev, enum sensor_channel chan)
40 {
41 const struct mcp970x_config *config = dev->config;
42 struct mcp970x_data *data = dev->data;
43 int ret;
44
45 if ((chan != SENSOR_CHAN_AMBIENT_TEMP) && (chan != SENSOR_CHAN_ALL)) {
46 return -ENOTSUP;
47 }
48
49 ret = adc_read_dt(&config->adc, &data->sequence);
50 if (ret != 0) {
51 LOG_ERR("adc_read: %d", ret);
52 }
53
54 return ret;
55 }
56
get(const struct device * dev,enum sensor_channel chan,struct sensor_value * val)57 static int get(const struct device *dev, enum sensor_channel chan, struct sensor_value *val)
58 {
59 const struct mcp970x_config *config = dev->config;
60 struct mcp970x_data *data = dev->data;
61 int32_t raw_val = data->raw;
62 int32_t t;
63 int ret;
64
65 __ASSERT_NO_MSG(val != NULL);
66
67 if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
68 return -ENOTSUP;
69 }
70
71 ret = adc_raw_to_millivolts_dt(&config->adc, &raw_val);
72 if (ret != 0) {
73 LOG_ERR("to_mv: %d", ret);
74 return ret;
75 }
76
77 if (config->family == FAMILY_MCP9700_9700A) {
78 t = (MC_PER_C * (raw_val - MV_AT_0C_MCP9700_9700A)) / T_COEFF_MCP9700_9700A;
79 } else {
80 int32_t t_coeff = 10 * T_COEFF_MCP9701_9701A; /* float to int */
81
82 t = (MC_PER_C * 10 * (raw_val - MV_AT_0C_MCP9701_9701A)) / t_coeff;
83 }
84
85 val->val1 = t / MC_PER_C;
86 val->val2 = 1000 * (t % MC_PER_C);
87
88 LOG_DBG("%d of %d, %dmV, %dmC", data->raw, (1 << data->sequence.resolution) - 1, raw_val,
89 t);
90
91 return 0;
92 }
93
94 static DEVICE_API(sensor, mcp970x_api) = {
95 .sample_fetch = fetch,
96 .channel_get = get,
97 };
98
init(const struct device * dev)99 static int init(const struct device *dev)
100 {
101 const struct mcp970x_config *config = dev->config;
102 struct mcp970x_data *data = dev->data;
103 int ret;
104
105 if (!adc_is_ready_dt(&config->adc)) {
106 LOG_ERR("ADC is not ready");
107 return -ENODEV;
108 }
109
110 ret = adc_channel_setup_dt(&config->adc);
111 if (ret != 0) {
112 LOG_ERR("setup: %d", ret);
113 return ret;
114 }
115
116 ret = adc_sequence_init_dt(&config->adc, &data->sequence);
117 if (ret != 0) {
118 LOG_ERR("sequence: %d", ret);
119 return ret;
120 }
121
122 data->sequence.buffer = &data->raw;
123 data->sequence.buffer_size = sizeof(data->raw);
124
125 return 0;
126 }
127
128 #define MCP970X_INIT(inst) \
129 static struct mcp970x_data mcp970x_##inst##_data = {0}; \
130 \
131 static const struct mcp970x_config mcp970x_##inst##_config = { \
132 .adc = ADC_DT_SPEC_INST_GET(inst), \
133 .family = DT_INST_ENUM_IDX(inst, family), \
134 }; \
135 \
136 SENSOR_DEVICE_DT_INST_DEFINE(inst, &init, NULL, &mcp970x_##inst##_data, \
137 &mcp970x_##inst##_config, POST_KERNEL, \
138 CONFIG_SENSOR_INIT_PRIORITY, &mcp970x_api);
139
140 DT_INST_FOREACH_STATUS_OKAY(MCP970X_INIT)
141
