reset: Add Raspberry Pi 4 firmware reset controller

Raspberry Pi 4's co-processor controls some of the board's HW
initialization process, but it's up to Linux to trigger it when
relevant. Introduce a reset controller capable of interfacing with
RPi4's co-processor that models these firmware initialization routines as
reset lines.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 58ba0c6..6d53561 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -153,4 +153,15 @@
 	depends on DM_RESET
 	help
 	  Support generic syscon mapped register reset devices.
+
+config RESET_RASPBERRYPI
+	bool "Raspberry Pi 4 Firmware Reset Controller Driver"
+	depends on DM_RESET && ARCH_BCM283X
+	default USB_XHCI_PCI
+	help
+	  Raspberry Pi 4's co-processor controls some of the board's HW
+	  initialization process, but it's up to Linux to trigger it when
+	  relevant. This driver provides a reset controller capable of
+	  interfacing with RPi4's co-processor and model these firmware
+	  initialization routines as reset lines.
 endmenu