[PATCH 1/2 v2] ARM64: juno: add GPIO keys

[Linus Walleij]

The Juno board has two keys connected to a PL061 GPIO block,
in accordance to DDI0524B "ARM Versatile Express Juno Development
Platform" revision 1.0, table 2-4 "GPIO (0) and GPIO (1) used
for additional user key entry". By trial-and-error I found that
these are connected to the two keys named "power" and "home"
on the motherboard.

Register the GPIO block and these two keys in the device tree
using the PL061 GPIO driver and the generic gpio keys.

- Map POWER, HOME, VOL+ and VOL- to the obvious input events.
- Map RLOCK to KEY_SCREENLOCK/KEY_COFFEE unless someone can
  explain better what this is for.
- Map the NMI button to KEY_SYSREQ as this is used like so
  in the SYSREQ debugging hack.

Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v1->v2:
- Register the GPIO block at 0x1d0000 as gpio0, as it turns out
  there is an unused GPIO block at 0x1e0000 as well.
- Label using capital letters.
- Map all 6 keys. Only the two highest GPIO lines are unused.
- Daniel: please look at this: the Juno has an NMI button, not
  on the primary IRQ controller (GIC) but on a cascaded GPIO
  controller. I have waited for this to happen, what are your
  thoughts about the possibilities to handle this with the
  priority-escalation trick you were devising for GIC's with
  FIQ stolen by TrustZone? As the Juno is a typical server
  design I suspect this is what we have to deal with for the
  "server-with-an-NMI-pushbutton" use case.
---
 arch/arm64/boot/dts/arm/juno-motherboard.dtsi | 61 +++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/arch/arm64/boot/dts/arm/juno-motherboard.dtsi b/arch/arm64/boot/dts/arm/juno-motherboard.dtsi
index 351c95bda89e..fde0cfad09de 100644
--- a/arch/arm64/boot/dts/arm/juno-motherboard.dtsi
+++ b/arch/arm64/boot/dts/arm/juno-motherboard.dtsi
@@ -54,6 +54,55 @@
 				regulator-always-on;
 			};
 
+			gpio_keys {
+				compatible = "gpio-keys";
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				button at 1 {
+					debounce_interval = <50>;
+					wakeup = <1>;
+					linux,code = <116>;
+					label = "POWER";
+					gpios = <&iofpga_gpio0 0 0x4>;
+				};
+				button at 2 {
+					debounce_interval = <50>;
+					wakeup = <1>;
+					linux,code = <102>;
+					label = "HOME";
+					gpios = <&iofpga_gpio0 1 0x4>;
+				};
+				button at 3 {
+					debounce_interval = <50>;
+					wakeup = <1>;
+					linux,code = <152>;
+					label = "RLOCK";
+					gpios = <&iofpga_gpio0 2 0x4>;
+				};
+				button at 4 {
+					debounce_interval = <50>;
+					wakeup = <1>;
+					linux,code = <115>;
+					label = "VOL+";
+					gpios = <&iofpga_gpio0 3 0x4>;
+				};
+				button at 5 {
+					debounce_interval = <50>;
+					wakeup = <1>;
+					linux,code = <114>;
+					label = "VOL-";
+					gpios = <&iofpga_gpio0 4 0x4>;
+				};
+				button at 6 {
+					debounce_interval = <50>;
+					wakeup = <1>;
+					linux,code = <99>;
+					label = "NMI";
+					gpios = <&iofpga_gpio0 5 0x4>;
+				};
+			};
+
 			ethernet at 2,00000000 {
 				compatible = "smsc,lan9118", "smsc,lan9115";
 				reg = <2 0x00000000 0x10000>;
@@ -148,5 +197,17 @@
 					clocks = <&soc_smc50mhz>;
 					clock-names = "apb_pclk";
 				};
+
+				iofpga_gpio0: gpio at 1d0000 {
+					compatible = "arm,pl061", "arm,primecell";
+					reg = <0x1d0000 0x1000>;
+					interrupts = <6>;
+					clocks = <&soc_smc50mhz>;
+					clock-names = "apb_pclk";
+					gpio-controller;
+					#gpio-cells = <2>;
+					interrupt-controller;
+					#interrupt-cells = <2>;
+				};
 			};
 		};
-- 
1.9.3