mb/google/poppy/variants/nami: Enable Synaptics touchpad

BUG=b:74595037
TEST=
1. emerge-nami coreboot chromeos-bootimage
2. check touchpad function
3. evtest
/dev/input/event5:	PNP0C50:00 06CB:CD84

Change-Id: I47cb1b13881f0d52860f0afe4bbca7483409de54
Signed-off-by: ivy_jian <ivy_jian@compal.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/25913
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/poppy/variants/nami/devicetree.cb b/src/mainboard/google/poppy/variants/nami/devicetree.cb
index b1c278c..c7a4c05 100644
--- a/src/mainboard/google/poppy/variants/nami/devicetree.cb
+++ b/src/mainboard/google/poppy/variants/nami/devicetree.cb
@@ -271,6 +271,15 @@
 				register "wake" = "GPE0_DW2_16"
 				device i2c 15 on end
 			end
+			chip drivers/i2c/hid
+				register "generic.hid" = ""PNP0C50""
+				register "generic.desc" = ""Synaptics Touchpad""
+				register "generic.irq" = "ACPI_IRQ_EDGE_LOW(GPP_E3_IRQ)"
+				register "generic.wake" = "GPE0_DW2_16"
+				register "generic.probed" = "1"
+				register "hid_desc_reg_offset" = "0x20"
+				device i2c 0x2c on end
+			end
 		end # I2C #1
 		device pci 15.2 on
                         chip drivers/i2c/hid