ssb: add GPIO driver

Register a GPIO driver to access the GPIOs provided by the chip.
The GPIOs of the SoC should always start at 0 and the other GPIOs could
start at a random position. There is just one SoC in a system and when
they start at 0 the number is predictable.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4591
Acked-by: Florian Fainelli <florian@openwrt.org>
diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
index 6fe2d10..87f0ddf 100644
--- a/drivers/ssb/main.c
+++ b/drivers/ssb/main.c
@@ -798,6 +798,12 @@
 	ssb_chipcommon_init(&bus->chipco);
 	ssb_extif_init(&bus->extif);
 	ssb_mipscore_init(&bus->mipscore);
+	err = ssb_gpio_init(bus);
+	if (err == -ENOTSUPP)
+		ssb_dprintk(KERN_DEBUG PFX "GPIO driver not activated\n");
+	else if (err)
+		ssb_dprintk(KERN_ERR PFX
+			   "Error registering GPIO driver: %i\n", err);
 	err = ssb_fetch_invariants(bus, get_invariants);
 	if (err) {
 		ssb_bus_may_powerdown(bus);