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-rw-r--r--src/mainboard/google/reef/variants/snappy/devicetree.cb11
1 files changed, 11 insertions, 0 deletions
diff --git a/src/mainboard/google/reef/variants/snappy/devicetree.cb b/src/mainboard/google/reef/variants/snappy/devicetree.cb
index f40c3307c6..6adf94c1b3 100644
--- a/src/mainboard/google/reef/variants/snappy/devicetree.cb
+++ b/src/mainboard/google/reef/variants/snappy/devicetree.cb
@@ -198,6 +198,17 @@ chip soc/intel/apollolake
register "desc" = ""Melfas Touchscreen""
register "irq" = "ACPI_IRQ_EDGE_LOW(GPIO_21_IRQ)"
register "probed" = "1"
+ # Melfas TS IC doesn't have reset pin design, current FW also not
+ # declare "ce-gpios" in ACPI _DSD to let Melfas TS driver to know
+ # "enable gpio#152 (VTSP) but because of kernel bug & Melfas TS driver
+ # is unable to separate clear power sequence path for certain
+ # TS IC (ex: MIT-410) and kernel will still obstain GPIO from _CRS
+ # by index "0" since no matched "gpio" in ACPI _DSD.
+ # coreboot needs to have "dummy pin" as workaround in order to let
+ # kernel driver grab "useless" GPIO to prevent Melfas TS driver cut
+ # power by driver itself.
+ register "reset_gpio" = "ACPI_GPIO_OUTPUT_ACTIVE_HIGH(GPIO_36)"
+ register "reset_delay_ms" = "1"
register "enable_gpio" = "ACPI_GPIO_OUTPUT_ACTIVE_HIGH(GPIO_152)"
register "enable_delay_ms" = "5"
register "has_power_resource" = "1"