mb/google/volteer: Implement touchscreen power sequencing

For touchscreens on volteer variants, drive the enable GPIO high
starting in romstage, then disable the reset GPIO in ramstage. This will
allow coreboot to detect the presence of i2c touchscreens during ACPI
SSDT generation (implemented in a subsequent commit).

BUG=b:121309055
TEST=tested with rest of patch train

Change-Id: Ie4c3b94594253ced6a875af78e6390cda8dcbc7d
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71181
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/mainboard/google/volteer/variants/trondo/gpio.c b/src/mainboard/google/volteer/variants/trondo/gpio.c
index 4ec02c5167..b759e3f1e0 100644
--- a/src/mainboard/google/volteer/variants/trondo/gpio.c
+++ b/src/mainboard/google/volteer/variants/trondo/gpio.c
@@ -292,3 +292,18 @@ const struct pad_config *variant_sleep_gpio_table(u8 slp_typ, size_t *num)
 	*num = 0;
 	return NULL;
 }
+
+/* GPIOs needed to be set in romstage. */
+static const struct pad_config romstage_gpio_table[] = {
+	/* Enable touchscreen, hold in reset */
+	/* A8  : I2S2_SFRM ==> EN_PP3300_TOUCHSCREEN */
+	PAD_CFG_GPO(GPP_A8, 1, DEEP),
+	/* C10 : UART0_RTS# ==> USI_RST_L */
+	PAD_CFG_GPO(GPP_C10, 0, DEEP),
+};
+
+const struct pad_config *variant_romstage_gpio_table(size_t *num)
+{
+	*num = ARRAY_SIZE(romstage_gpio_table);
+	return romstage_gpio_table;
+}