apollolake: Add handler for finding ACPI path for GPIO

Add a handler for soc/intel/apollolake to return the ACPI path for
GPIOs.  There are 4 GPIO "communities" on apollolake that each have a
different ACPI device so return the appropriate name for the different
communities.

Change-Id: I596c178b7813ac6aaeb4f2685bb916f5b78e049b
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/14859
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/apollolake/gpio.c

@@ -114,3 +114,21 @@ void gpio_set(gpio_t gpio_num, int value)
 	reg |= !!value & PAD_CFG0_TX_STATE;
 	iosf_write(comm->port, config_offset, reg);
 }
+
+const char *gpio_acpi_path(gpio_t gpio_num)
+{
+	const struct pad_community *comm = gpio_get_community(gpio_num);
+
+	switch (comm->port) {
+	case GPIO_NORTH:
+		return "\\_SB.GPO0";
+	case GPIO_NORTHWEST:
+		return "\\_SB.GPO1";
+	case GPIO_WEST:
+		return "\\_SB.GPO2";
+	case GPIO_SOUTHWEST:
+		return "\\_SB.GPO3";
+	}
+
+	return NULL;
+}