Add PS/2 GPIO Bit-banging driver

drivers/ps2/CMakeLists.txt

@@ -6,3 +6,4 @@ zephyr_library_sources_ifdef(CONFIG_PS2_XEC		ps2_mchp_xec.c)
 zephyr_library_sources_ifdef(CONFIG_USERSPACE           ps2_handlers.c)
 zephyr_library_sources_ifdef(CONFIG_PS2_NPCX		ps2_npcx_channel.c)
 zephyr_library_sources_ifdef(CONFIG_PS2_NPCX		ps2_npcx_controller.c)
+zephyr_library_sources_ifdef(CONFIG_PS2_GPIO		ps2_gpio.c)

drivers/ps2/Kconfig

@@ -12,6 +12,7 @@ if PS2
 
 source "drivers/ps2/Kconfig.xec"
 source "drivers/ps2/Kconfig.npcx"
+source "drivers/ps2/Kconfig.gpio"
 
 module = PS2
 module-str = ps2

drivers/ps2/Kconfig.gpio

@@ -0,0 +1,41 @@
+# Copyright (c) 2017 Linaro Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+DT_COMPAT_PS2_GPIO := gpio-ps2
+
+config PS2_GPIO
+	bool "GPIO bit banging PS/2 support"
+	default $(dt_compat_enabled,$(DT_COMPAT_PS2_GPIO))
+	help
+	  Enable software driven (bit banging) PS/2 support using GPIO pins
+
+if PS2_GPIO
+
+# PS/2 events must be processed within 30-50us. Therefore we shift the
+# BT_CTLR_LLL_PRIO from 0 to 1 and BT_CTLR_ULL_* priorities from 1 to 2.
+# We then set the gpio priority to 0.
+#
+# On top of this, the following has to be added to the device tree:
+# &gpiote {
+# 	interrupts = < 0x6 0 >;
+# };
+#
+# This allows the PS/2 interrupts to be triggered in time.
+
+config BT_CTLR_ADVANCED_FEATURES
+	default y
+
+config BT_CTLR_LLL_PRIO
+	default 1
+
+config BT_CTLR_ULL_HIGH_PRIO
+	default 2
+
+config BT_CTLR_ULL_LOW_PRIO
+	default 2
+
+config PS2_GPIO_INTERRUPT_LOG_ENABLED
+	bool "Enable extensive interrupt logging."
+	default n
+
+endif # PS2_GPIO