[PATCH] ARM: tegra: Add embedded controller to ASUS SL101

[Florian Krischer <florian.krischer@fkr.dev>]

The ASUS Eee Pad Slider SL101 has an embedded controller for its
built-in sliding keyboard.

Describe the EC on the PTA/GEN2 I2C mux leg. The EC responds at 0x19,
with DockRAM at 0x1b. AP_WAKE is GPIO S2 and EC_REQUEST is GPIO S3.

The node has been tested on a physical SL101 with EC model
ASUS-EP102-DOCK and firmware SL101-0202. With the ASUS Transformer EC
MFD/serio driver and the SL101 event-protocol fixups, the built-in
keyboard works through serio/atkbd.

This patch depends on the ASUS Transformer EC binding that provides the
"asus,sl101-ec-dock" compatible.

Signed-off-by: Florian Krischer <florian.krischer@fkr.dev>
---
 arch/arm/boot/dts/nvidia/tegra20-asus-sl101.dts | 13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/arch/arm/boot/dts/nvidia/tegra20-asus-sl101.dts
+++ b/arch/arm/boot/dts/nvidia/tegra20-asus-sl101.dts
@@ -59,3 +59,16 @@
 		};
 	};
 };
+
+&lvds_ddc {
+	embedded-controller@19 {
+		compatible = "asus,sl101-ec-dock";
+		reg = <0x19>, <0x1b>;
+		reg-names = "ec", "dockram";
+
+		interrupt-parent = <&gpio>;
+		interrupts = <TEGRA_GPIO(S, 2) IRQ_TYPE_LEVEL_LOW>;
+
+		request-gpios = <&gpio TEGRA_GPIO(S, 3) GPIO_ACTIVE_LOW>;
+	};
+};
--