xbee: added new recipe for XBee hardware initialization

This recipe adds a script and a related systemd service that
configures two GPIOs (user defined, or else platform-defaults) as
output and sets them to the appropriate value for initializing the
XBee socket:
 - XBEE_SLEEP_RQ: is set low, for running the XBee
 - XBEE_RESET_N: is set low and then high, to reset the XBee

The service triggers on the condition that the UART TTY device node
pointed to by variable XBEE_UART exists.

Signed-off-by: Hector Palacios <hector.palacios@digi.com>

https://jira.digi.com/browse/DEL-6366

meta-digi-arm/conf/machine/ccimx8x-sbc-express.conf

@@ -32,6 +32,10 @@ SERIAL_CONSOLES ?= "115200;ttyLP2"
 # Bluetooth tty
 BT_TTY ?= "ttyLP1"
 
+# XBee
+XBEE_RESET_N_GPIO ?= "397"
+XBEE_SLEEP_RQ_GPIO ?= "400"
+
 # U-Boot script to be copied to the boot image
 BOOT_SCRIPTS = "boot.scr:boot.scr"
 

meta-digi-arm/conf/machine/ccimx8x-sbc-pro.conf

@@ -32,6 +32,10 @@ SERIAL_CONSOLES ?= "115200;ttyLP2"
 # Bluetooth tty
 BT_TTY ?= "ttyLP1"
 
+# XBee
+XBEE_RESET_N_GPIO ?= "220"
+XBEE_SLEEP_RQ_GPIO ?= "216"
+
 # U-Boot script to be copied to the boot image
 BOOT_SCRIPTS = "boot.scr:boot.scr"
 

meta-digi-arm/conf/machine/include/ccimx8x.inc

@@ -34,6 +34,7 @@ MACHINE_EXTRA_RDEPENDS += " \
     mca-tool \
     parted \
     u-boot-fw-utils \
+    xbee-init \
 "
 
 MACHINE_EXTRA_RRECOMMENDS += " \

meta-digi-dey/recipes-connectivity/xbee/xbee.bb

@@ -0,0 +1,40 @@
+# Copyright (C) 2019 Digi International Inc.
+
+SUMMARY = "Digi XBee initialization"
+DESCRIPTION = "Initialization scripts for XBee hardware of Digi boards"
+SECTION = "base"
+LICENSE = "GPL-2.0"
+LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/GPL-2.0;md5=801f80980d171dd6425610833a22dbe6"
+
+SRC_URI = " \
+    file://xbee-init \
+    file://xbee-init.service \
+"
+S = "${WORKDIR}"
+
+do_install() {
+	install -d ${D}${sysconfdir}/init.d/
+	install -m 0755 ${WORKDIR}/xbee-init ${D}${sysconfdir}/
+	ln -sf /etc/xbee-init ${D}${sysconfdir}/init.d/xbee-init
+	sed -i -e "s,##XBEE_RESET_N_GPIO##,${XBEE_RESET_N_GPIO},g" \
+	       -e "s,##XBEE_SLEEP_RQ_GPIO##,${XBEE_SLEEP_RQ_GPIO},g" \
+	       ${D}${sysconfdir}/xbee-init
+
+	install -d ${D}${systemd_unitdir}/system/
+	install -m 0644 ${WORKDIR}/xbee-init.service ${D}${systemd_unitdir}/system/
+}
+
+PACKAGES =+ "${PN}-init"
+FILES_${PN}-init = " \
+    ${sysconfdir}/xbee-init \
+    ${sysconfdir}/init.d/xbee-init \
+    ${systemd_unitdir}/system/xbee-init.service \
+"
+INITSCRIPT_PACKAGES += "${PN}-init"
+INITSCRIPT_NAME_${PN}-init = "xbee-init"
+INITSCRIPT_PARAMS_${PN}-init = "start 19 2 3 4 5 . stop 21 0 1 6 ."
+
+SYSTEMD_SERVICE_${PN}-init = "xbee-init.service"
+
+PACKAGE_ARCH = "${MACHINE_ARCH}"
+COMPATIBLE_MACHINE = "(ccimx8x)"

meta-digi-dey/recipes-connectivity/xbee/xbee/xbee-init

@@ -0,0 +1,70 @@
+#!/bin/sh
+
+# Linux GPIOs on XBee lines
+XBEE_RESET_N_GPIO="##XBEE_RESET_N_GPIO##"
+XBEE_SLEEP_RQ_GPIO="##XBEE_SLEEP_RQ_GPIO##"
+
+# request_gpio <gpio_nr>
+request_gpio_out() {
+	local SG_GPIONR="${1}"
+	local SG_GPIOPATH="/sys/class/gpio/gpio${SG_GPIONR}"
+
+	[ -d "${SG_GPIOPATH}" ] || printf "%s" "${SG_GPIONR}" > /sys/class/gpio/export
+	printf out > "${SG_GPIOPATH}/direction" && sleep .2
+}
+
+# free_gpio <gpio_nr>
+free_gpio() {
+	local SG_GPIONR="${1}"
+	local SG_GPIOPATH="/sys/class/gpio/gpio${SG_GPIONR}"
+
+	[ -d "${SG_GPIOPATH}" ] && printf "%s" "${SG_GPIONR}" > /sys/class/gpio/unexport
+}
+
+# set_gpio_value <gpio_nr> <value>
+set_gpio_value() {
+	local SG_GPIONR="${1}"
+	local SG_GPIOVAL="${2}"
+	local SG_GPIOPATH="/sys/class/gpio/gpio${SG_GPIONR}"
+
+	printf out > "${SG_GPIOPATH}/direction" && sleep .2
+	printf "${SG_GPIOVAL}" > "${SG_GPIOPATH}/value" && sleep .2
+}
+
+xbee_init() {
+	# Power cycle XBEE_RESET_N
+	request_gpio_out ${XBEE_RESET_N_GPIO}
+	set_gpio_value ${XBEE_RESET_N_GPIO} 0
+	set_gpio_value ${XBEE_RESET_N_GPIO} 1
+
+	# Set low XBEE_SLEEP_RQ
+	request_gpio_out ${XBEE_SLEEP_RQ_GPIO}
+	set_gpio_value ${XBEE_SLEEP_RQ_GPIO} 0
+}
+
+xbee_stop() {
+	free_gpio ${XBEE_RESET_N_GPIO}
+	free_gpio ${XBEE_SLEEP_RQ_GPIO}
+}
+
+case "$1" in
+	start)
+		echo -n "Starting XBee hardware: "
+		xbee_init
+		echo "done."
+		;;
+	stop)
+		echo -n "Stopping XBee hardware: "
+		xbee_stop
+		echo "done."
+		;;
+	restart)
+		$0 stop
+		sleep 1
+		$0 start
+		;;
+	*)
+		echo "Usage: $0 {start|stop|restart}"
+		exit 1
+		;;
+esac

meta-digi-dey/recipes-connectivity/xbee/xbee/xbee-init.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=XBee GPIOs initialization
+Before=ModemManager.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/etc/xbee-init start
+ExecStop=/etc/xbee-init stop
+
+[Install]
+WantedBy=multi-user.target