pico: Implement GET_TEMP telecommand to return temperatura data

This commit implements a telecommand for temperature retrieval.  It
uses the port number (11) and temperature data type (float) defined in
MCS.

temp.c is modified to use zephyr's sensor API (fetch and get) for
temperature retrieval.  The Fetch and Get API is selected because the
Zephyr kernel of this satellite is version 3.7 and the newer Read and
Decode API is still unstable.

Signed-off-by: Riho Natsushima <nasshi7224@gmail.com>

pico/prj.conf

@@ -7,3 +7,5 @@ CONFIG_SERIAL=y
 CONFIG_UART_INTERRUPT_DRIVEN=y
 CONFIG_POSIX_API=y
 CONFIG_LOG=y
+CONFIG_SENSOR=y
+CONFIG_LM75=y

pico/src/pico_csp.c

@@ -12,6 +12,8 @@
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(csp, CONFIG_MAIN_LOG_LEVEL);
 
+#include "temp.h"
+
 #define ROUTER_STACK_SIZE (256U)
 #define SERVER_STACK_SIZE (1024U)
 #define ROUTER_PRIO       (0U)
@@ -24,6 +26,8 @@ LOG_MODULE_REGISTER(csp, CONFIG_MAIN_LOG_LEVEL);
 #define PICO_UART0_PARITY   (0U)
 #define PICO_CSP_ADDR       (26U)
 
+#define PORT_T (11U) /* for get temperature */
+
 extern csp_conf_t csp_conf;
 
 static void server(void);
@@ -82,6 +86,17 @@ static void server(void)
 		csp_packet_t *packet;
 		while ((packet = csp_read(conn, 50)) != NULL) {
 			switch (csp_conn_dport(conn)) {
+			case PORT_T:
+				float temp;
+				int result = get_temp(&temp);
+				if (result < 0) {
+					LOG_ERR("Failed to get temperature");
+				} else {
+					LOG_DBG("Temperature: %.2f℃", (double)temp);
+					memcpy(packet->data, &temp, sizeof(temp));
+					packet->length = sizeof(temp);
+					csp_send(conn, packet);
+				}
 			default:
 				csp_service_handler(packet);
 				break;

pico/src/temp.c

@@ -4,27 +4,51 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include "temp.h"
+
 #include <zephyr/drivers/i2c.h>
+#include <zephyr/device.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/sensor.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(temp, LOG_LEVEL_DBG);
 
 #define DEV_ADDR   (0x4e)
 #define START_ADDR (0x00)
 #define RESOLUTION (0.0625f)
 #define BIT_SHIFT  (4)
 
-int get_temp(const struct device *dev, float *temp)
-{
-	int ret;
-	uint8_t tmp[2];
+int get_temp(float *temp) {
+
+	const struct device *const temp_sensor = DEVICE_DT_GET_ANY(lm75);
+	struct sensor_value temp_val;
+	int r;
+	int rc;
+
+    	if (!device_is_ready(temp_sensor)) {
+		LOG_ERR("Temperature sensor device not ready");
+		return -ENODEV;
+	}
 
 	if (temp == NULL) {
 		return -EINVAL;
 	}
 
-	ret = i2c_burst_read(dev, DEV_ADDR, START_ADDR, tmp, sizeof(tmp));
-	if (ret == 0) {
-		tmp[1] = tmp[1] >> BIT_SHIFT;
-		*temp = (int8_t)tmp[0] + (float)tmp[1] * RESOLUTION;
+	rc = sensor_sample_fetch(temp_sensor);
+	if ( rc < 0 ) {
+		LOG_ERR("Failed to fetch sensor data, error: %d", rc);
+		return rc;
+	}
+
+	r = sensor_channel_get(temp_sensor, SENSOR_CHAN_AMBIENT_TEMP, &temp_val);
+	if ( r < 0 ) {
+		LOG_ERR("Failed to get sensor data, error: %d", r);
+		return r;
 	}
 
-	return ret;
+	*temp = (float)(temp_val.val1 + (float)(temp_val.val2) /1000000.0f);
+	LOG_DBG("Temperature: %d.%06d°C", temp_val.val1, temp_val.val2);
+
+    	return 0;
 }

pico/src/temp.h

@@ -6,6 +6,4 @@
 
 #pragma once
 
-#include <zephyr/device.h>
-
-int get_temp(const struct device *dev, float *temp);
+int get_temp(float *temp);

pico/uart1.overlay

@@ -24,3 +24,13 @@
 		};
 	};
 };
+
+&i2c0 {
+	status = "okay";
+	clock-frequency = <100000>;
+
+	lm75@4c{
+		compatible = "lm75";
+		reg = <0x4C>;
+	};
+};