ARM: bcm2835: Add the Raspberry Pi firmware driver

This gives us a function for making mailbox property channel requests
of the firmware, which is most notable in that it will let us get and
set clock rates.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index d8de6a8..9e06188 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -139,6 +139,13 @@
 	bool
 	depends on ARM || ARM64
 
+config RASPBERRYPI_FIRMWARE
+	tristate "Raspberry Pi Firmware Driver"
+	depends on BCM2835_MBOX
+	help
+	  This option enables support for communicating with the firmware on the
+	  Raspberry Pi.
+
 source "drivers/firmware/broadcom/Kconfig"
 source "drivers/firmware/google/Kconfig"
 source "drivers/firmware/efi/Kconfig"