1 /*
2 * Copyright (c) 2024 Adrien Leravat
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #define DT_DRV_COMPAT hc_sr04
8
9 #include <zephyr/kernel.h>
10 #include <zephyr/drivers/gpio.h>
11 #include <zephyr/drivers/sensor.h>
12 #include <zephyr/logging/log.h>
13
14 LOG_MODULE_REGISTER(HC_SR04, CONFIG_SENSOR_LOG_LEVEL);
15
16 #define HC_SR04_MM_PER_MS 171
17
18 static const uint32_t hw_cycles_per_ms = sys_clock_hw_cycles_per_sec() / 1000;
19
20 struct hcsr04_data {
21 const struct device *dev;
22 struct gpio_callback gpio_cb;
23 struct k_sem sem;
24 uint32_t start_cycles;
25 atomic_t echo_high_cycles;
26 };
27
28 struct hcsr04_config {
29 struct gpio_dt_spec trigger_gpios;
30 struct gpio_dt_spec echo_gpios;
31 };
32
33 static void hcsr04_gpio_callback(const struct device *dev, struct gpio_callback *cb, uint32_t pins);
34
hcsr04_configure_gpios(const struct hcsr04_config * cfg)35 static int hcsr04_configure_gpios(const struct hcsr04_config *cfg)
36 {
37 int ret;
38
39 if (!gpio_is_ready_dt(&cfg->trigger_gpios)) {
40 LOG_ERR("GPIO '%s' not ready", cfg->trigger_gpios.port->name);
41 return -ENODEV;
42 }
43 ret = gpio_pin_configure_dt(&cfg->trigger_gpios, GPIO_OUTPUT_LOW);
44 if (ret < 0) {
45 LOG_ERR("Failed to configure '%s' as output: %d", cfg->trigger_gpios.port->name,
46 ret);
47 return ret;
48 }
49
50 if (!gpio_is_ready_dt(&cfg->echo_gpios)) {
51 LOG_ERR("GPIO '%s' not ready", cfg->echo_gpios.port->name);
52 return -ENODEV;
53 }
54 ret = gpio_pin_configure_dt(&cfg->echo_gpios, GPIO_INPUT);
55 if (ret < 0) {
56 LOG_ERR("Failed to configure '%s' as output: %d", cfg->echo_gpios.port->name, ret);
57 return ret;
58 }
59
60 return 0;
61 }
62
hcsr04_configure_interrupt(const struct hcsr04_config * cfg,struct hcsr04_data * data)63 static int hcsr04_configure_interrupt(const struct hcsr04_config *cfg, struct hcsr04_data *data)
64 {
65 int ret;
66
67 /* Disable initially to avoid spurious interrupts. */
68 ret = gpio_pin_interrupt_configure(cfg->echo_gpios.port, cfg->echo_gpios.pin,
69 GPIO_INT_DISABLE);
70 if (ret < 0) {
71 LOG_ERR("Failed to configure '%s' as interrupt: %d", cfg->echo_gpios.port->name,
72 ret);
73 return -EIO;
74 }
75 gpio_init_callback(&data->gpio_cb, &hcsr04_gpio_callback, BIT(cfg->echo_gpios.pin));
76 ret = gpio_add_callback(cfg->echo_gpios.port, &data->gpio_cb);
77 if (ret < 0) {
78 LOG_ERR("Failed to add callback on '%s': %d", cfg->echo_gpios.port->name, ret);
79 return -EIO;
80 }
81 return 0;
82 }
83
hcsr04_init(const struct device * dev)84 static int hcsr04_init(const struct device *dev)
85 {
86 const struct hcsr04_config *cfg = dev->config;
87 struct hcsr04_data *data = dev->data;
88 int ret;
89
90 k_sem_init(&data->sem, 0, 1);
91
92 ret = hcsr04_configure_gpios(cfg);
93 if (ret < 0) {
94 return ret;
95 }
96
97 ret = hcsr04_configure_interrupt(cfg, data);
98 if (ret < 0) {
99 return ret;
100 }
101
102 return 0;
103 }
104
hcsr04_gpio_callback(const struct device * dev,struct gpio_callback * cb,uint32_t pins)105 static void hcsr04_gpio_callback(const struct device *dev, struct gpio_callback *cb, uint32_t pins)
106 {
107 struct hcsr04_data *data = CONTAINER_OF(cb, struct hcsr04_data, gpio_cb);
108 const struct hcsr04_config *cfg = data->dev->config;
109
110 if (gpio_pin_get(dev, cfg->echo_gpios.pin) == 1) {
111 data->start_cycles = k_cycle_get_32();
112 } else {
113 atomic_set(&data->echo_high_cycles, k_cycle_get_32() - data->start_cycles);
114 gpio_pin_interrupt_configure_dt(&cfg->echo_gpios, GPIO_INT_DISABLE);
115 k_sem_give(&data->sem);
116 }
117 }
118
hcsr04_sample_fetch(const struct device * dev,enum sensor_channel chan)119 static int hcsr04_sample_fetch(const struct device *dev, enum sensor_channel chan)
120 {
121 const struct hcsr04_config *cfg = dev->config;
122 struct hcsr04_data *data = dev->data;
123 int ret;
124
125 ret = gpio_pin_interrupt_configure_dt(&cfg->echo_gpios, GPIO_INT_EDGE_BOTH);
126 if (ret < 0) {
127 LOG_ERR("Failed to set configure echo pin as interrupt: %d", ret);
128 return ret;
129 }
130
131 /* Generate 10us trigger */
132 ret = gpio_pin_set_dt(&cfg->trigger_gpios, 1);
133 if (ret < 0) {
134 LOG_ERR("Failed to set trigger pin: %d", ret);
135 return ret;
136 }
137
138 k_busy_wait(10);
139
140 ret = gpio_pin_set_dt(&cfg->trigger_gpios, 0);
141 if (ret < 0) {
142 LOG_ERR("Failed to set trigger pin: %d", ret);
143 return ret;
144 }
145
146 if (k_sem_take(&data->sem, K_MSEC(10)) != 0) {
147 LOG_ERR("Echo signal was not received");
148 return -EIO;
149 }
150 return 0;
151 }
152
hcsr04_channel_get(const struct device * dev,enum sensor_channel chan,struct sensor_value * val)153 static int hcsr04_channel_get(const struct device *dev, enum sensor_channel chan,
154 struct sensor_value *val)
155 {
156 const struct hcsr04_data *data = dev->data;
157 uint32_t distance_mm;
158
159 if (chan != SENSOR_CHAN_DISTANCE) {
160 return -ENOTSUP;
161 }
162
163 distance_mm = HC_SR04_MM_PER_MS * atomic_get(&data->echo_high_cycles) /
164 hw_cycles_per_ms;
165 return sensor_value_from_milli(val, distance_mm);
166 }
167
168 static DEVICE_API(sensor, hcsr04_driver_api) = {
169 .sample_fetch = hcsr04_sample_fetch,
170 .channel_get = hcsr04_channel_get
171 };
172
173
174 #define HC_SR04_INIT(index) \
175 static struct hcsr04_data hcsr04_data_##index = { \
176 .dev = DEVICE_DT_INST_GET(index), \
177 .start_cycles = 0, \
178 .echo_high_cycles = ATOMIC_INIT(0), \
179 }; \
180 static struct hcsr04_config hcsr04_config_##index = { \
181 .trigger_gpios = GPIO_DT_SPEC_INST_GET(index, trigger_gpios), \
182 .echo_gpios = GPIO_DT_SPEC_INST_GET(index, echo_gpios), \
183 }; \
184 \
185 SENSOR_DEVICE_DT_INST_DEFINE(index, &hcsr04_init, NULL, &hcsr04_data_##index, \
186 &hcsr04_config_##index, POST_KERNEL, \
187 CONFIG_SENSOR_INIT_PRIORITY, &hcsr04_driver_api); \
188
189 DT_INST_FOREACH_STATUS_OKAY(HC_SR04_INIT)
190
