WIP: userland proximity driver

Signed-off-by: Baocheng Su <[email protected]>

recipes-core/iot2050-proximity-driver/files/src/Makefile

@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: Copyright (c) Siemens AG, 2025
+# SPDX-FileContributor: Authored by Su Bao Cheng <[email protected]>
+
+CROSS_COMPILE ?= aarch64-linux-gnu-
+
+CC = $(CROSS_COMPILE)gcc
+
+LDFLAGS = -lsystemd
+
+TARGET = iot2050-pxmtd
+
+INSTALL ?= install
+
+DESTDIR ?= /
+
+SRC = main.c \
+	dbus-service.c \
+	sensor.c
+
+.PHONY: all clean install
+
+all: $(TARGET)
+
+$(TARGET): $(SRC)
+	$(CC) $(CFLAGS) -o $(TARGET) $(SRC) $(LDFLAGS)
+
+clean:
+	rm -f $(TARGET)
+
+install:
+	$(INSTALL) -v -d $(DESTDIR)/usr/bin
+	$(INSTALL) -v -d $(DESTDIR)/etc/dbus-1/system.d
+	$(INSTALL) -v -m 0755 $(TARGET) $(DESTDIR)/usr/bin
+	$(INSTALL) -v -m 0644 com.siemens.iot2050.pxmt.conf \
+		$(DESTDIR)/etc/dbus-1/system.d
+	$(INSTALL) -v -d ${DESTDIR}/lib/systemd/system/
+	$(INSTALL) -v -m 0644 iot2050-proximity-driver.service\
+		${DESTDIR}/lib/systemd/system/

recipes-core/iot2050-proximity-driver/files/src/com.siemens.iot2050.pxmt.conf

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+<!DOCTYPE busconfig PUBLIC
+ "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig>
+  <policy user="root">
+    <allow own="com.siemens.iot2050.pxmt"/>
+    <allow send_interface="com.siemens.iot2050.pxmt"/>
+  </policy>
+</busconfig>

recipes-core/iot2050-proximity-driver/files/src/dbus-service.c

@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: MIT
+ * SPDX-FileCopyrightText: Copyright (c) Siemens AG, 2025
+ * SPDX-FileContributor: Authored by Su Bao Cheng <[email protected]>
+ */
+
+#include <systemd/sd-bus.h>
+#include <errno.h>
+#include <sys/capability.h>
+#include "dbus-service.h"
+
+typedef int (*retrieve_callback_t)(uint16_t *);
+
+static retrieve_callback_t iot2050_pxmtd_retrieve_cb = NULL;
+
+static int iot2050_pxmtd_retrieve(sd_bus_message *m,
+				  void *userdata,
+				  sd_bus_error *ret_error)
+{
+	if (!iot2050_pxmtd_retrieve_cb)
+		return -ENXIO;
+
+	uint16_t ps_val;
+	int ret = iot2050_pxmtd_retrieve_cb(&ps_val);
+	if (ret < 0)
+		return ret;
+
+	return sd_bus_reply_method_return(m, "q", ps_val);
+}
+
+static const sd_bus_vtable iot2050_pxmtd_vtable[] = {
+	SD_BUS_VTABLE_START(0),
+	SD_BUS_METHOD("Retrieve",
+		      SD_BUS_NO_ARGS,
+		      "q",
+		      iot2050_pxmtd_retrieve,
+		      SD_BUS_VTABLE_UNPRIVILEGED),
+	SD_BUS_VTABLE_END
+};
+
+int dbus_serve(retrieve_callback_t cb)
+{
+	sd_bus_slot *slot = NULL;
+	sd_bus *bus = NULL;
+	int ret;
+
+	ret = sd_bus_open_system(&bus);
+	if (ret < 0) {
+		fprintf(stderr, "Failed to connect to system bus: %s\n",
+			strerror(-ret));
+		goto out;
+	}
+
+	iot2050_pxmtd_retrieve_cb = cb;
+
+	ret = sd_bus_add_object_vtable(bus, &slot,
+				       "/com/siemens/iot2050/pxmt",
+				       "com.siemens.iot2050.pxmt",
+				       iot2050_pxmtd_vtable, NULL);
+	if (ret < 0) {
+		fprintf(stderr, "Failed to set dbus service property: %s\n",
+			strerror(-ret));
+		goto out;
+	}
+
+        ret = sd_bus_request_name(bus, "com.siemens.iot2050.pxmt", 0);
+        if (ret < 0) {
+                fprintf(stderr, "Failed to acquire service name: %s\n",
+			strerror(-ret));
+                goto out;
+        }
+
+        for (;;) {
+                ret = sd_bus_process(bus, NULL);
+                if (ret < 0) {
+                        fprintf(stderr, "Failed to process bus: %s\n",
+				strerror(-ret));
+                        goto out;
+                }
+                if (ret > 0)
+                        continue;
+
+                ret = sd_bus_wait(bus, (uint64_t) -1);
+                if (ret < 0) {
+                        fprintf(stderr, "Failed to wait on bus: %s\n",
+				strerror(-ret));
+                        goto out;
+                }
+        }
+
+	ret = 0;
+out:
+	sd_bus_slot_unref(slot);
+	sd_bus_unref(bus);
+
+	return ret;
+}

recipes-core/iot2050-proximity-driver/files/src/dbus-service.h

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+/* SPDX-License-Identifier: MIT
+ * SPDX-FileCopyrightText: Copyright (c) Siemens AG, 2025
+ * SPDX-FileContributor: Authored by Su Bao Cheng <[email protected]>
+ */
+
+#ifndef IOT2050_PXMTD_DBUS_SERVICE_H
+#define IOT2050_PXMTD_DBUS_SERVICE_H
+
+#include <stdint.h>
+
+typedef int (*retrieve_callback_t)(uint16_t *);
+
+int dbus_serve(retrieve_callback_t cb);
+
+#endif /* IOT2050_PXMTD_DBUS_SERVICE_H */

recipes-core/iot2050-proximity-driver/files/src/iot2050-proximity-driver.service

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+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: Copyright (c) Siemens AG, 2025
+# SPDX-FileContributor: Authored by Su Bao Cheng <[email protected]>
+
+[Unit]
+Description=Userspace driver for the proximity sensor of IOT2050
+# Only run on IOT2050-SM variant
+ConditionFirmware=device-tree-compatible(siemens,iot2050-advanced-sm)
+ConditionVirtualization=!container
+
+[Service]
+Type=dbus
+BusName=com.siemens.iot2050.pxmt
+ExecStart=/usr/bin/iot2050-pxmtd
+Restart=always
+RestartSec=5
+ProtectSystem=strict
+ProtectHome=true
+NoNewPrivileges=true
+User=root
+
+[Install]
+WantedBy=multi-user.target
+Alias=dbus-com.siemens.iot2050.pxmt.service

recipes-core/iot2050-proximity-driver/files/src/main.c

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+/* SPDX-License-Identifier: MIT
+ * SPDX-FileCopyrightText: Copyright (c) Siemens AG, 2025
+ * SPDX-FileContributor: Authored by Su Bao Cheng <[email protected]>
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "sensor.h"
+#include "dbus-service.h"
+
+int main()
+{
+	setbuf(stdout, NULL);
+
+	int ret = init_sensor();
+	if (ret < 0) {
+		fprintf(stderr, "Failed to initialize the sensor: %s\n",
+			strerror(-ret));
+		exit(EXIT_FAILURE);
+	}
+
+	return dbus_serve(retrieve_sensor_data) == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}