mb/google/zork: Switch USI_RESET to active low polarity for v3.6+

v3.6 of reference schematics have switched the polarity of reset
signal to touchscreen controller from active high to active low. This
change updates the default configuration in baseboard gpio tables to
set the reset GPIO to output low and override tables in variants to set the
reset GPIO to output high. Additionally, devicetree by default exposes
ACTIVE_LOW configuration for reset GPIO. In order to support pre-v3.6
boards, reset GPIO is updated to ACTIVE_HIGH based on board version.

BUG=b:161937506

Change-Id: I092f274d8eb1920a1cd6d3eccbe8f26b0b28928a
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44192
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 52 insertions, 1 deletions

diff --git a/src/mainboard/google/zork/variants/baseboard/ramstage_common.c b/src/mainboard/google/zork/variants/baseboard/ramstage_common.c
index 8a6fa47ceb..a55bdf2c81 100644
--- a/src/mainboard/google/zork/variants/baseboard/ramstage_common.c
+++ b/src/mainboard/google/zork/variants/baseboard/ramstage_common.c
@@ -6,14 +6,16 @@
 #include <device/device.h>
 #include <drivers/amd/i2s_machine_dev/chip.h>
 #include <drivers/i2c/generic/chip.h>
+#include <drivers/i2c/hid/chip.h>
 #include <drivers/usb/acpi/chip.h>
 #include <ec/google/chromeec/ec.h>
 #include <soc/gpio.h>
+#include <soc/iomap.h>
 #include <soc/pci_devs.h>
 
 extern struct chip_operations drivers_amd_i2s_machine_dev_ops;
 extern struct chip_operations drivers_i2c_generic_ops;
-
+extern struct chip_operations drivers_i2c_hid_ops;
 
 static void update_hp_int_odl(void)
 {
@@ -202,3 +204,52 @@ void variant_bluetooth_update(void)
 
 	baseboard_remove_bluetooth_reset_gpio();
 }
+
+void variant_touchscreen_update(void)
+{
+	DEVTREE_CONST struct device *mmio_dev = NULL;
+	struct device *child = NULL;
+
+	/*
+	 * By default, devicetree/overridetree entries for touchscreen device are configured to
+	 * match v3.6 of reference schematics. So, if the board is using v3.6+ schematics, no
+	 * additional work is required here. For maintaining support for pre-v3.6 boards, rest
+	 * of the code in this function finds all entries that correspond to touchscreen
+	 * devices (identified by reset_gpio being set to GPIO_140) and updates them as per
+	 * pre-v3.6 version of schematics:
+	 * 1. reset_gpio is marked as active high.
+	 */
+	if (variant_uses_v3_6_schematics())
+		return;
+
+	while (1) {
+		mmio_dev = dev_find_path(mmio_dev, DEVICE_PATH_MMIO);
+		if (mmio_dev == NULL)
+			break;
+		if (mmio_dev->path.mmio.addr == APU_I2C2_BASE)
+			break;
+	}
+
+	if (mmio_dev == NULL)
+		return;
+
+	while ((child = dev_bus_each_child(mmio_dev->link_list, child)) != NULL) {
+		struct drivers_i2c_generic_config *cfg;
+
+		if (child->chip_ops == &drivers_i2c_generic_ops) {
+			cfg = config_of(child);
+		} else if (child->chip_ops == &drivers_i2c_hid_ops) {
+			struct drivers_i2c_hid_config *hid_cfg;
+			hid_cfg = config_of(child);
+			cfg = &hid_cfg->generic;
+		} else {
+			continue;
+		}
+
+		/* If reset_gpio is set to GPIO_140, assume that this is touchscreen device. */
+		if (cfg->reset_gpio.pins[0] != GPIO_140)
+			continue;
+
+		cfg->reset_gpio.active_low = 0;
+	}
+}