mb/google/guybrush: Add Elan Touchpad configuration

Enable Touchpad by configuring the enable GPIO to logic high. Add
touchpad configuration for ELAN touchpad.

BUG=b:182207444
TEST=Build and boot to OS in Guybrush. Ensure that the trackpad events
are detected using evtest.

Change-Id: Ib47fbb33f2b181eb85f6ded98a5b0ce08fbc7b64
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51962
Reviewed-by: Mathew King <mathewk@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/guybrush/variants/baseboard/gpio.c

@@ -22,7 +22,7 @@ static const struct soc_amd_gpio base_gpio_table[] = {
 	/* EN_PP3300_WLAN */
 	PAD_GPO(GPIO_6, LOW),
 	/* EN_PP3300_TCHPAD */
-	PAD_GPO(GPIO_7, LOW),
+	PAD_GPO(GPIO_7, HIGH),
 	/* EN_PWR_WWAN_X */
 	PAD_GPO(GPIO_8, LOW),
 	/* SOC_TCHPAD_INT_ODL */

src/mainboard/google/guybrush/variants/guybrush/overridetree.cb

@@ -61,4 +61,14 @@ chip soc/amd/cezanne
 		.early_init = true,
 	}"
 
+	device ref i2c_0 on
+		chip drivers/i2c/generic
+			register "hid" = ""ELAN0000""
+			register "desc" = ""ELAN Touchpad""
+			register "irq_gpio" = "ACPI_GPIO_IRQ_EDGE_LOW(GPIO_9)"
+			register "wake" = "GEVENT_22"
+			register "probed" = "1"
+			device i2c 15 on end
+		end
+	end # I2C0
 end	# chip soc/amd/cezanne