mb/google/volteer/eldrid: Describe the privacy_gpio

Add information regarding the privacy pin on the overridetree and the
gpio.

BUG=b:171888751

Change-Id: I1ab19a863715ba5a928dd7c16402d398e5475edc
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46964
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/mainboard/google/volteer/Kconfig

@@ -14,6 +14,7 @@ config BOARD_GOOGLE_BASEBOARD_VOLTEER
 	select DRIVERS_SPI_ACPI
 	select DRIVERS_SOUNDWIRE_ALC5682
 	select DRIVERS_SOUNDWIRE_MAX98373
+	select DRIVERS_USB_ACPI
 	select EC_GOOGLE_CHROMEEC
 	select EC_GOOGLE_CHROMEEC_BOARDID
 	select EC_GOOGLE_CHROMEEC_SKUID

src/mainboard/google/volteer/variants/eldrid/gpio.c

@@ -63,7 +63,7 @@ static const struct pad_config override_gpio_table[] = {
 	PAD_CFG_GPO(GPP_C23, 1, DEEP),
 
 	/* D4  : IMGCLKOUT0# ==> CAMMERA_SWITCH */
-	PAD_CFG_GPI(GPP_D4, NONE, DEEP),
+	PAD_CFG_GPI_INT(GPP_D4, NONE, PLTRST, EDGE_BOTH),
 	/* D6  : SRCCLKREQ1# ==> WLAN_CLKREQ_ODL */
 	PAD_CFG_NF(GPP_D6, NONE, DEEP, NF1),
 	/* D8  : SRCCLKREQ3# ==> SD_CLKREQ_ODL */

src/mainboard/google/volteer/variants/eldrid/overridetree.cb

@@ -227,6 +227,10 @@ chip soc/intel/tigerlake
 					chip drivers/usb/acpi
 						register "desc" = ""USB2 Camera""
 						register "type" = "UPC_TYPE_INTERNAL"
+						# The Linux Kernel does not allow an inverted BOTH_EDGE irq
+						# So we need to use GpioIO() instead of GpioInt()
+						# https://www.kernel.org/doc/Documentation/acpi/gpio-properties.txt
+						register "privacy_gpio"  = "ACPI_GPIO_INPUT_ACTIVE_LOW(GPP_D4)"
 						device ref usb2_port5 on end
 					end
 					chip drivers/usb/acpi